Archive for the ‘Costa Rica’ Tag

BIODIVERSITY MOST ORDINARY   1 comment


Veridion Adventures. Philip Davison. Rainforest animals. Rainforest plants

Day by day the rains lessen.  Day by day the sun is breaking through a little more, warming up the ground and consequently the air.  Evaporation causes the relative humidity to rise.  We are almost there, almost into the dry season.  It won’t be long before we start to lament the lack of precipitation but let us at least enjoy the first few dry weeks without complaint.  There have now been 3 dry sunny days in succession.  It doesn’t take long for the muddy trails to start drying out.

Biodiversity Most Ordinary: Net-winged Planthopper

There are certain insects that you see regularly in a variety of locations but they don’t excite your interest because there is nothing outstanding about them; no bright color, no unusual shape or weird behavior.  They are just a general insect.

Net-winged Planthoppers fall into this category of ordinary.  I see them but I am never inspired to point the lens in their direction.  Last week as I was searching the vegetation, scrutinizing the grass blades and poking around on the ground looking for a subject that I may have never seen before, one of the Net-winged Planthoppers landed in front of me.  Well here was an opportunity to photograph something even if the subject was mundane.

Rainforest insects. Hemiptera. Homoptera. Nogodinidae. Biolleyana costalis. Net-winged Planthopper. Costa Rica. Philip Davison. Veridion Adventures.

Net-winged Planthopper, (Biolleyana costalis)

I am probably doing the Net-winged Planthopper a disservice as they are as important as everything else within the complex system of interactions that make up the tropical rainforest ecosystem.  They are true bugs and belong in the homopteran family: Nogodinidae, which taxonomically is regarded as being Neotropical.  Information regarding their life histories are non-existent at worst to scarce at best.  I think this individual is one of the 3 known Biollyana species, possibly Biolleyana costalis.  They are plant sap feeders and use the long piercing mouthparts to tap into the plant’s vascular system.

There are 22 families of planthoppers consisting of approximately 12, 500 species.  Despite their method of feeding, very few of them are vectors for plant borne diseases and are not especially known as agricultural pests.

Biodiversity Most Ordinary: Better Red Than Dead

Not too far from the Net-winged Planthopper I found another puzzling creature.  My initial thought was that this is a Hemipteran nymph, probably Heteroptera but as to what family I do not know.

What caught my eye was the fact that this nymph was colored fiery red and I found it on a bright red Heliconia flower.  This invites certain questions.  Red is a commonly found color used by plants for their flowers in a tropical rainforest.  Red is the complementary color to green.  It is a very hot color whereas green is very cool color.  Red will vividly stand out from a surrounding sea of green vegetation.  Many pollinators have acute color vision and will spot the potential food source, (normally nectar), advertised by the plant.  The payback is the transference of pollen and therefore the completion of reproduction for the stationary plant.

Rainforest Insects. Hemiptera. Heteroptera. Costa Rica. Philip Davison. Veridion Adventures.

Heteroptera nymph

So does the adult bug select for red flowers on which to lay its eggs and the sap-sucking nymph that hatches is red and blends in with its host plant?  Might it be that the nymph upon hatching feeds on the plant tissue and takes in the plants red pigments such as carotenes, which it then stores to subsequently give it the matching color?  It may well be that is was simply a coincidence and the red nymph just happened to be on a red flower, there are many red heteropteran nymphs that feed on green leaves which defies logic as they then become very visible.  But nature has its ways, which unlike the red nymphs on green leaves, is not always obvious.

Biodiversity Most Ordinary: Tales of the Flesh

Flies are distained by most people, and with good reason; they can be both annoying and dangerous.  For the most part, flies possess wings, atypical for insects – only one pair of wings.  Adult flies are liquid feeders and that embraces just about all liquids, including blood, particularly vertebrate blood.  The larvae feed on liquids and solids.

Excellent fliers with unspeakably bad habits, (from a human point of view), and the ability to travel over long distances give the Diptera, (True Flies), a reputation as one of the most serious vectors of human borne disease and pathogens.

Flies require protein in their diet, a first-rate source of which is blood, mammalian blood, human blood.  Mosquitoes are probably the most widely know vectors used by blood living parasites as vectors between species and individuals within a species.  Mosquitoes are not alone, they are joined by Black Flies, Sand Flies and Horse Flies as bringing nuisance, illness and death to their victims.

This Flesh Fly, (Sarcophagidae sp), was perched on a log in the sun.  Flesh Flies could be regarded as a typical dipteran, to look at there is nothing outstanding.  They are not particularly large or have strange anatomical features.  There are about 600 species of Flesh Flies in the neotropics and to the layman they mostly all look the same.

Rainforest Insects. Diptera. Sarcophagidae. Flesh Fly. Costa Rica. Philip Davison. Veridion Adventures.

Flesh Fly, (Sarcophagidae sp)

Because they are common and widespread, their unsavory habit of feeding on carrion and excrement as well as associating with humans points the finger of accusation in being the mechanical vector in disease transmission.  Unlike most dipterans Flesh Flies are ovoviviparous, the larvae hatch from the eggs as they are laid.  In some cases this may be an open wound in a mammal where the maggot immediately begins to consume the rotting tissue, hence the name Flesh Fly.  Who knows what this individual might have been carrying on its feet and liquid feeding tongue but I was never going to get close enough to find out.

Philip Davison Is a Biologist, Writer and Photographer Based in Costa Rica

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RAINFOREST DIVERSITY: SOMETHING FOR EVERYONE   2 comments


Veridion Adventures. Philip Davison. Rainforest animals. Rainforest plants

There is still no let up in the rainy conditions.  The good news is that the days are more overcast than dark and the rain is now falling more as a drizzle rather than a deluge.  As with recent weeks the sun has been shining once in a while so hopefully as we move into December the rains will abate and we will be able to say the dry season has started.

Rainforest Diversity – Beetles

The wet conditions have kept me indoors more than I would like.  On those occasions that I have been out and about there was not too much animal life to point the camera at.  When you read about the diversity of fauna and flora contained within a tropical rainforest you would expect to be surrounded by a non-stop progression of subjects.  That is not always the case.  However if you persist and concentrate on looking a little more closely at the vegetation then something is bound to turn up.

Beetles are the most numerously named group of animals on the planet.  Surely there have to be beetles wherever you look.  Well they aren’t as obvious as you might imagine.  Many of them are secretive, ground-living or wood-boring insects.  Looking diligently at the leaves as I made my way along a sunny path and hoping for at least one or two individuals of any insect to be out I saw a small beetle that I had never seen before.  Given that Costa Rica has 47,000 named species of beetle and I would never profess to being a specialist coleopterist, then the fact that I did not know what species I was looking at should come as no surprise.

Rainforest beetles. Coleoptera. Cerambycidae. Cerambycinae. Long-horned Beetle. Costa Rica. Philip Davison. Veridion Adventures.

Long-horned Beetle, (Cerambycinae sp)

I can generally make an immediate I.D. to family level and that was not hard with this one.  The length of the antennae were the give away, the very long length, far longer than the body.  This was a small Long-horned Beetle, family: Cerambycidae.  This one also had a long pronotum, (the area behind the head), and a very long body.  I was guessing it belonged in the subfamily: Cerambycinae.  I now had to go and research online to see if I could find the genus and species.  Alas, my scrutinizing a great many photographs failed to result in a match but at least I have the image should I find further reference material in the future.

Rainforest Diversity – Fungi

The beetles are matched by the fungi in terms of numbers and also a lack of reference material for the non-specialist to identify them to species level.  Many of the biologists working with tropical taxa tend to be specialists.  I am more of a generalist and enjoy all forms of life; plants, animals, fungi and no matter whether they are extant or extinct.  My areas of specialty are butterflies, reptiles and amphibians.  It can be frustrating sometimes when a name cannot be found as that might reveal information about the life-history of the organism and its role in the ecosystem.  Essentially it helps establish those links that increase our understanding of the system, what happens if those links are severed and conservation management strategies that would be required to stop the system collapsing.

Rainforest fungi. Agaricales. Hygrophoraceae. Costa Rica. Osa Peninsula. Philip Davison. Veridion Adventures.

Dried Mushroom, (Hygrocybe sp?)

So it was that I found a mushroom growing from the side of a rotten tree trunk.  I had seen and photographed this species before and, like so many others, had not been abled to identify it to species level.  There are 2000 named species of fungi in Costa Rica but estimates of how many species actually exist in this small country are as high as 70 000, so you can see the problem, you may be looking at one of the 68 000 estimated species that have not as yet been discovered.

This specimen was somewhat dried out and partly eaten.  The aspect gives a good view of the gills under the cap.  Given the features I have to work with I would guess the genus to be Hygrocybe, but I would not be held to that.  Within the gills you can also see a fungus fly.  These are flies that lay their eggs in the mushroom and when the larvae emerge they are surrounded by a ready food supply.

Rainforest Diversity – Spiders

Spiders are the eighth most numerously named group of animals on the planet.  As with the beetles and fungi, reference material is sparse for Costa Rican species.  However, this was one I did know.  It is not an uncommon spider.  They are nocturnal and build very distinctive horizontal webs.  It is an Orchard Spider, (Leucauge venusta).

They are not large spiders and can be easily overlooked.  But if you get up close you will find it has rather lovely markings.  The opisthosoma is patterned with curving bands colored with white, red, yellow and blue.

Rainforest Spiders. Arachnida. Araneae. Tetragnathidae. Leucauge venusta. Orchard Spider. Osa Peninsula. Costa Rica. Philip Davison. Veridion Adventures.

Orchard Spider, (Leucauge venusta)

Orchard Spiders are prone to being parasitized by Ichneumonid Wasps.  The wasp finds the spider and injects an egg into its abdomen.  The egg hatches and the wasp larva proceeds to suck the spider’s internal bodily fluids.  Outwardly this does not seem to affect the spider’s behavior and it continues web building as normal.  But then something insidious happens.  The wasp larva produces a chemical that allows it to sequester the spiders brain.  The chemical changes the spiders web building behavior and it produces a web which is not conducive to capturing insects but rather acts as a protective silken home for the pupating wasp.  The zombified spider, now of no value to the wasp, dies.  Nature can be both cruel and fascinating at the same time.

Rainforest Diversity – Butterflies

For someone passionate about butterflies I am in the right country.  Rainforests cover 6% the total land surface of the Earth and yet contain an estimated 50% of the worlds biodiversity.  Costa Rica, with only 0.3% of the planets terrestrial area is estimated to house 5% of the world’s total biodiversity.  The Osa Peninsula in the south west of the country is one of the most biodiverse localities in Costa Rica.  There are a lot of butterflies here.  I have recorded approximately 400 of the 1250 species to be found in this small Central American Republic, that is 32% found at Cabo Matapalo, the tip of this tiny piece of land sticking out into the Pacific Ocean.

Even here on Cabo Matapalo there is a large diversity of habitat and different butterflies prefer different conditions.  Many of the butterflies live up at canopy level and are beyond daily recording techniques.  There are butterflies that prefer open sunny gardened areas, some can be more commonly found along forest edges.  Then there are those presence will only be recorded in the gloomy and shadowy world that exists beneath the canopy, some at higher levels and some always hugging the ground.

I have nothing against bright, gaudy coloration but my liking is for more cryptic and subtle forms which when examined close up are every bit as beautiful as their showy cousins.  Among the more subdued colored butterflies are the Browns or Satyrs belonging to the family: Nymphalidae, subfamily: Satyrinae.  The Satyrinae are notable for the number of eyespots on the underside of the wings.  The ground colors are browns and grays patterned with ochres and umbers.

Rainforest Butterflies. Nymphalidae. Satyrinae. Pareuptychia ocirrhoe. Two-band Satyr. Osa Peninsula. Costa Rica. Philip Davison. Veridion Adventures.

Two-band Satyr, (Pareuptychia ocirrhoe)

The Two-banded Satyr, (Pareuptychia ocrirrhoe), has white dorsal wing surfaces and a bouncy flight close to the ground which gives it a flickering appearance.  I found this one flying along the forest edge on a very overcast day.  They respond quickly to movement so you have to approach slowly and deliberately in order for them to stay perched.

The Two-banded Satyr is normally found singly.  The larvae feed on grasses, (Poaceae), and the adults feed on rotting fruit and fungi, a diet that may account for them living longer, (several weeks), than other butterflies, (several days).

Philip Davison Is a Biologist, Writer and Photographer Based in Costa Rica

ARMY ANTS:  A LIVING WAVE OF BLACK DEATH   6 comments


Veridion Adventures. Philip Davison. Rainforest animals. Rainforest plants

November is upon us.  The wet season continues, relentless heavy rain falling if not all day then at least part thereof.  One day last week over 14 inches of rain fall in an overnight deluge.  The following day the forest trails were more akin to newly formed streams, the water flowing downhill until it reached a point where it could tumble into the main creek that runs through the grounds, swelling its volume and increasing its velocity to that of a raging torrent.   There have been some dry, sunny days and if the weather continues its normal pattern then progressively as we move through the month the number of rainless days should increase.

I have been away for a month and upon my return, as with each and every year, the first thing I hear is the call of the Summer Tanager, (Piranga rubra), which has spent the summer in North America.  Not much has changed in the area while I was away.   The resident wildlife can still be found without any effort.  The White-nosed Coati, (Nasua narica), populations are growing at a steady and sustained rate.  I have never seen as many wandering the grounds as I do now.  The solitary males are normally bold creatures, but the females tend to be shy and retiring.  Now, however, the females and their young will allow you to approach very close without scurrying off into the shelter of the trees.

Rainforest lizards. Costa Rica. Polychrotidae. Anolis osae. Osa Anole. Philip Davison. Veridion Adventures.

Osa Anolis, (Anolis osae)

The wet conditions have proved to be conducive in allowing the amphibians to continue their courtship and breeding.  There are not so many egg masses present as in the main breeding period, (May – July), but there are still several species spawning on a nightly basis.  Feeding on the eggs are the Cat-eyed Snakes, (Leptodeira septentrionalis), which can be found every night by the pond.  The ever-present anoles of several species can be seen in the forest.  The commonest and most obvious is the Osa Anole, (Anolis osae), with its bright orange dewlap.  If one male is signaling to another to leave his territory then you can’t miss that flash of color against the dark background.

Ants Are Everywhere

Ants are ubiquitous insects in the forest.  On the trees you will see lines of Tiger Ants, (Camponotus sericeiventris), walking in line, foraging for food.  They receive their name from the black and yellow coloration rather than an aggressive nature.  In the lawns you would be well advised to avoid stepping in those small powdering mounds of earth that betray the presence of Fire Ants, (Solonopsis sp), living just beneath the surface.  I have never known anything so small cause so much pain as the fire ants.  The problem is that they are so small you don’t know you are covered in them until they start to bite and they all do so together.  It would be almost impossible to miss the presence of Leaf-cutter Ants, (Atta cephalotes), in these forests, whether it be descending the tree trunks with freshly cut leaf fragments or seeing lines of ants moving as a green river, snaking across the forest floor as they make their way back to, the nests with, what essentially is composting material for their fungus gardens.  Leaf-cutter Ant nests occur every 100 meters or so in whatever direction throughout the forest and can easily be identified by the large waste tips of excavated material marking the nests’ peripheral boundaries.

Rainforest insects. Hymenoptera. Formicidae. Atta cephalotes. Leaf-cutter Ant. Philip Davison. Veridion Adventures.

Pebble-capped towers formed by heavy rain on Leaf-cutter Ant nest waste tip

Army Ants:  A Living Wave of Black Death

It is a warm day, the rain has stopped, the sun is shining and you are quietly walking through the forest, binoculars strung around your neck and camera in hand.  The air is still and there is little sound bar the occasional call of a bird here and there and the soft white noise of calling insects which is not too intrusive.  You walk in a state of reverie, not thinking about anything in particular, your eyes scanning the vegetation for small subjects to photograph or watching for movement that may indicate a bird or mammal is moving across your path.  It is a day for enjoying your surroundings and contemplating the life contained within.  You are blissfully unaware of the carnage being carried out in the forest ahead.

As you make your way forward you start to hear more birds calling.  Some of the sounds you are familiar with; a Black-hooded Antshrike, (Thamnophilus bridgesi), Bicolored Antbirds, (Gymnophythis leucaspis), and Chestnut-backed Antbirds, (Myrmeciza exul).  This seems as if it might provide some good photographic opportunities so you make sure the camera is ready with the correct settings.  Now some other birds fly past you and land on the tree trunks, most of them a variety of treecreepers; Streak-headed, (Lepidocolaptes souleyetii), Tawny-winged, (Dendrocincla anabatina), and Ruddy, (Dendrocinclo homochroa).  The bird calls are increasing in intensity, excitement and volume as you make your way to where they seem to be congregating.  As you approach you can see them briefy dropping from the vegetation to the ground and back up again.  There is another sound, a hum which pervades the air.  Having left your dreamlike state and become more acutely aware you see that you are surrounded by flies buzzing everywhere. You see one or two Gray-headed Tanagers, (Eucomectis penicillata), amongst the mixed bird flock, the presence of which along with the flies provide the clues as to what is happening.   Finally you hear, a sound like softly falling rain and yet there is not a cloud in the sky.  From about 5 meters in front of you and advancing rapidly towards you like a sheet of black polythene being pulled across the forest floor is a foraging front of Army Ants, (Echiton burchellii); a living wave of black death.

Rainforest ants. Hymenoptera. Formicidae. Dorylinae. Eciton burchellii. Army Ant. Costa Rica. Philip Davison. Veridion Adventures.

Army Ant, (Eciton burchellii), on the march

The feet of thousands of miniature assassins moving as one across the dried leaves give the illusion of rain falling.  You stand dumbstruck by the scene playing out in front of you.  As the procession of annihilation moves closer you can see down by your feet beetles, cockroaches and crickets running for their lives.  These are the lucky few.  The killers are insatiable.  Any small creature unfortunate enough to caught in their unrelenting path will be overwhelmed, stung to death, and then decapitated, dismembered and disemboweled.  The wickedly sharp mandibles of the army ant hunters slash and cut through exoskeleton, muscle and connective tissue.  The victim’s mutilated body fragments are then carried away by the mindless insect ghouls to provide a feast macabre for the larvae.  As fascinating to witness as this bloodbath at the macro level is, you had better move.  The ants are now crossing the path all around your feet. You might be too big for them to tackle, but the long stinger and virulent toxin can cause a lot of pain.

Rainforest insects. Hymenoptera. Formicidae. Dorylinae. Eciton burchellii. Army Ant. Costa Rica. Philip Davison. Veridion Adventures.

Army Ants, (Eciton burchellii), carrying severed spider leg back to feed larvae

For those insects capable of flight and able to escape the ravaging mandibles of the ants, the danger is not over.  The birds were attracted to the ant swarm to take advantage of the free meal they provide by flushing insects from their hiding places.  Gray-headed Tanagers are obligative followers of the army ants.  Wherever they are, you will find the tanagers.  The flies are there for the same reason.  These are Coffin Flies, (Phoridae sp).  When an insect attempts to escape by taking flight, the parasitic phorid fly swoops in, lays an egg and flies out again.  The eggs will hatch and the grub will eat the victim.

Army Ants are one of the major predators in the forest.  They rank alongside Boa Constrictors, Harpy Eagles and Jaguars as one of the top of the food pyramid predators in the forest.  They are a nomadic ant and they have to be nomadic because being such a super-efficient predator, should they settle in any one area for any length of time, they would deplete it of all small forms of life very quickly.

They have 2 three week cycles; a nomadic stage when they move in a flowing column of ants, the queen travelling with them, until they find a new hunting ground.  They do not construct a nest, they make a bivouac, generally at the base of a tree, which is a huge ball of ants held together by the interlinking of legs. The queen moves to center and swells up.  She starts to lay approx. 60, 000 eggs per day.  When the eggs hatch and the larvae emerge, the emit a pheromone which elicits a hunting response from the other workers.  They then move through the forest in a front anything up to 60 feet, (20 meters), across and take all small forms of life in their path: insects, small frogs, small lizards, small snakes, fledgling birds, if it is there then they will have it.  Once it has been butchered into small pieces, these are taken back via feeder columns to the bivouac to feed the larvae.  When the larvae pupate, the hunting response is switched off and  they return to the nomadic stage making their way through the forest once again.

A New Assassin

Rainforest ants. Hymenoptera. Formicidae. Dorylinae. Nomamyrmex sp. Army Ant. Costa Rica. Philip Davison. Veridion Adventures

Army Ant, (Nomamyrmex sp) carrying pupa from Leaf-cutter Ant, (Atta cephalotes), nest

There are many species of Army Ant and the species described above is the most commonly found in the area Echiton burchellii.  Last week I found a species that I had never seen before.  As well as slaughtering prey items on the forest floor, army ants will also enter the nests of other ants and take out the eggs, larvae, pupae, workers and queen.  They one ant they fight shy of taking on are the Leaf-cutter Ants.  There may be several hundred thousand in an army ant colony, there can be up to 8 million in a leaf-cutter ant colony.  The soldier leaf-cutters are huge and equipped with razor sharp mandibles.  They are programmed to fight to the death.  The army ants would lose so many of their own numbers if they were to raid a leaf-cutter ant nest.  Even if they come across them on a trail they will not interfere with them.

Rainforest animals. Hymenoptera. Formicidae. Atta cephalotes. Leaf-cutter Ant. Philip Davison. Veridion Adventures.

Leaf-cutter Ant, (Atta cephalotes), soldier

It was to my surprise therefore when last week a watched for the first time an army ant raid on a leaf-cutter ant nest.  Luckily I had the camera in my hand and found a place to lie down and take photos.  On this occasion the leaf-cutters seemed to be helpless to stop the nest being ransacked.  When I downloaded the images and looked at the images I did not recognize the species at all.  Despite their distinctive flat, square heads, extensive searching produced no I.D.  Eventually I found one photo and some information.  The genus is Nomamyrmex and it contains two species.  I am not sure which one I had been watching but I was happy to have witnessed an event I had never seen before being carried out by an ant I had never seen before and had the photos to prove it.

Rainforest insects. Hymenoptera. Formicidae. Dorylinae. Nomamyrmex sp. Army Ant. Philip Davison. Veridion Adventures.

Army Ants, (Nomamyrmex sp), raiding Leaf-cutter Ant, (Atta cephalotes), nest

Philip Davison Is a Biologist, Writer and Photographer Based in Costa Rica

 

CUCKOO WASPS:  A DAZZLING PARASITE   2 comments


Wildlife, nature, fauna and flora of Costa Rica.

Now the weather has taken a significant change.  The rains that are expected to fall in September have started in earnest.  The rain is now falling all day and on most days.  This is good news for the frogs and this year the breeding continues on without a drop in intensity.  Every night there are large numbers of calling males.  The females are obviously responding because every morning there are lots of freshly spawned eggs.

After 17 years of data collection for my study, “Using amphibian and butterfly populations as a measure of environmental health”, I have decided to call it a day and now have to sit down and analyze the data.  Essentially I have been collecting data on population dynamics of butterflies and amphibians as well as recording daily weather conditions.  I look at changes in butterfly populations measured against temperature and amphibian populations measured against precipitation.  There are a great many other variables to be taken into consideration but watch this space for news of what the data might be showing us.

Butterflies in the Sun

Due to the constant rain and the trails running like streams, I have not been able to spend as much time outside as I would normally wish.  However, on the one day I did manage to get out and take some photographs I was rewarded with a mixed bag of goodies of which only one was new to me.

One morning the sun was shining and the butterflies were taking advantage of its warming rays.  The Lantana camara bushes are always a big nectar draw for the butterflies and this day proved to be no different.  Although there were nowhere near the number of species found during drier periods of the year there were enough to try and take a few shots.

One very small but distinctive butterfly that I have a particular liking for, (I don’t know why), is the Tropical Checkered Skipper, (Pyrgus oileus).  It is a fairly common skipper with a wide geographical distribution from southern North America and through into Costa Rica.  At a distance the black and white checkered pattern make it stand out against the green of the grass where it is normally found flying close to the ground.  When seen close up the wings and body are covered in a grey/blue fur.  The females tend to be a darker overall color.  The caterpillars feed on plants in the family: Malvaceae, of which there are several species growing in abundance locally.

Rainforests. Butterflies. Costa Rica. Veridion Adventures. Hesperiidae. Pyrginae. Pyrgus oileus.

Tropical Checkered Skipper, (Pyrgus oileus)

They belong in the family: Hesperiidae and the subfamily: Pyrginae or Spreadwing Skippers due to their habit of basking with the wings wide open.  There are approximately 50 species in the genus: Pyrgus and they can be found throughout Europe, Asia, North, Central and South America.  You are more likely to find Tropical Checkered Skippers in open sunny locations which is where I found this one.

Feeding on the nectar of the same patch of Lantana was yet another Spreadwing Skipper but one which looked completely different to the Checkered Skipper.  This was a Long-tailed Skipper, (Urbanus proteus), notable for the two long tail-like extensions of the hind wings.  There are several species of Long-tailed Skippers in the immediate area but each one has distinctive markings to the wings.  The dorsal surface of the abdomen and the wings are covered in metallic green hairs.  Again it is a widespread species ranging from southern North America, down through Central America and into South America.  The larvae feed on leguminous vines of which there are many species growing locally.  In North America it is sometimes considered a pest as it feeds on commercially grown beans.

Rainforests. Butterflies. Costa Rica. Veridion Adventures. Hesperiidae. Pyrginae. Urbanus proteus

Long-tailed Skipper, (Urbanus proteus)

This individual can be seen using its proboscis to probe for and suck nectar from the Lantana blooms.  One of the changes I have documented over the past 17 years is the progressive increase in annual average temperatures. One of the impacts this may have on butterfly populations is with increasing temperatures there will be increasing evaporation of the nectar.  This in turn causes an exponential increase in nectar viscosity.  We could end up with a situation whereby if the temperature increases to the point where the nectar is too viscous for the butterflies to suck up, then they may well not be able to feed, bringing about starvation, death and a collapse in butterfly numbers.  This is one of many variables I have to take into consideration when looking at the fact that we have had a 35% decline in butterfly species over the past 17 years.

Cuckoo Wasps: A Dazzling Parasite

While watching the butterflies flit back and forth, only stopping momentarily to take a feed of nectar, I noticed a tiny metallic green insect, only about 10mm long.  It was on top of a leaf at eye level and not moving.  It was striking in that the green was very reflective, it looked like a piece of metallic foil.  I was looking at a Cuckoo Wasp.  I have only ever photographed one in the past so if this one did not move then here was a second opportunity beckoning.  I slowly lifted the camera and got the shot but as I moved my position for a head on photo it took to the air and disappeared.

Cuckoo wasps are solitary wasps of the order: Hymenoptera, which includes bees, wasps and ants amongst others.  They belong in the family: Chrysididae, after the Greek word Chrysis – golden vessel.  They are also known as Jewel Wasps and they certainly have a jewel-like quality to them.  The refraction of light produces the spectacular metallic coloration, similar to the iridescent blues of the Blue Morpho butterflies.  In this case it is the multi-layered waxy cuticle of the wasp’s exoskeleton that produces the refraction.  There are about 3,000 named species of Cuckoo Wasps and they are found in most parts of the planet.

Rainforest insects. Hymenoptera. Chrysididae. Cuckoo Wasp.

Dazzling parasite, Cuckoo Wasp, (Chrysididae sp)

The name Cuckoo Wasp refers to the fact that, depending on species, they are either parasitoids or kleptoparasites preying upon other wasps.  Like any parasite dealing with a dangerous host it has to have evolved behavioral methods that allow it to get in and get out without being discovered or be killed.  To that end it has a very sneaky strategy.

A female Cuckoo Wasp will case the joint she is about to infiltrate.  She watches and waits for a female Digger Wasp to begin making a burrow.  When the Digger Wasp starts to bring in paralyzed prey on which to lay her eggs, the Cuckoo Wasp either hangs onto the immobilized victim and will be dragged into the burrow, or she waits until the Digger Wasp has left on another foraging trip and she will stealthily slip into the burrow.  If caught in the act, all is not lost.  Some species of Cuckoo Wasp have a concave underside and can roll into a ball.  The sting of the enraged host will not penetrate the heavily pitted exoskeleton of this now globe-like emerald.  The host has to physically carry the Cuckoo in the nest out in its jaws where it will then sit and watch till it can strike again.

Having subverted the hosts defenses, the female Cuckoo Wasp lays its eggs.  Some species are kleptoparasites, once the egg hatches and the larva emerges it will kill and eat the host larva and then consumes the food the host female is providing for it.  It remains undetected by mimicking the chemical signature odor of the host.  Others wait for the host larva to grow and then kill and consume it before it pupates.  Then like its avian namesake, it is the Cuckoo that thrives within the nest of its unwitting host and eventually emerges as a new parasite.  They parasitize a wide variety of hosts from solitary wasps and bees, to sawflies and walking sticks.  Unlike many other wasps where the ovipositor is modified into a lethal sting, the Cuckoo Wasp has a modified ovipositor and reduced venom sac so has no potentially lethal means of attack or defense.

Who would of thought as I photographed this gorgeous glowing emerald insect that it would have such an insidious life history.

A Collection of Queens

Another wasp nest that I have been walking past over the past month or so has been not only gradually increasing in size but is now populated by more adult wasps tending it.  It is the nest of one of the Social Paper Wasps, (Polistes sp).  The original queen had created a few cells beneath a leaf in each of which she laid an egg.  The eggs hatched, the larvae she provided with a food of chewed up insects until they were large enough.  She then capped the cell of the now pupa and waited for it to emerge.  The new wasp is one of the original queen’s offspring and like their mother they are equally capable of mating and reproducing.

Rainforest insects. Paper Wasps. Hymenoptera. Vesperidae. Polistinae. Costa Rica. Veridion Adventures.

Female Paper Wasp, (Polistes sp), guarding her nest.

To begin with they help with the nest, building more cells, tending the larval siblings, foraging for food and helping the nest to increase in size.  The cells are constructed from masticated vegetative material.  Prey is caught and chewed up for the larvae to feed.  The sting is only used defensively.  They will attack any potential predator that approaches too close.  So, my approach was one of great stealth.  I took a few took a few exposures but the flash was beginning to antagonize them and one took flight and started buzzing around my head which was my cue to slowly back off and leave them to their business.

The other females usually have reduced ovarian systems but dominance of the original queen is not always assured.  Fights break out and a new queen can become established within the hierarchy taking over the major reproductive role.  When the male wasps emerge, they may stay on the nest for some time before leaving.

Philip Davison Is a Biologist, Writer and Photographer Based in Costa Rica

OGRE-FACED SPIDER: STARING YOU DOWN   4 comments


Wildlife, nature, fauna and flora of Costa Rica.

The weather is beginning to change.  There are now more rainy days with brief intervals of sun, generally shining in the morning.  Most of the nights are wet, with the rain beginning in the early hours of the evening then continuing through till dawn.  The rain is not heavy but it is constant.  This will now be the pattern until mid-November.  The opportunities to get out and take photographs is going to become more and more limited as the days and weeks go by.

Ogre-faced Spider

Sometimes you just have to be lucky and find yourself in the right place at the right time.  Many years ago I had taken some photographs of a particular species of spider and since then had been hoping to see this species again to get a close up of one of its startling features, the eyes.  I have come across it several times over the years but, unfortunately, never when I was carrying the camera.  Last week my luck changed and I found one without actually looking for it and I did have my camera in hand.

The spider in question is an Ogre-faced Spider, (Deinopis sp), of the family: Deinopidae.  Once you see the spider in close up then the reason for the name will be revealed.  Those two large, forward-facing eyes give the appearance of a mythical ogre staring at you.

Rainforest animals. Rainforest Spiders. Ogre-faced spider. Deinopidae. Costa Rica.

Ogre-faced Spider, (Deinopis sp), easier to see at an angle

The Ogre-faced spiders are not typical orb-weavers, they belong to a group known as lace-web weavers and have evolved a different means of employing silk to catch prey.  There are only 57 species of Ogre-faced spiders but they are found throughout the tropics.  They have long legs and a long abdomen, (opisthosoma).  If they do move, it is slowly and deliberately.  The coloration matches the tree bark on which they are commonly found hanging in a head down position.  During the day they lie flat against the tree to avoid being seen.  But as the sun sets they move into position and set about constructing the ingenious part of its prey capturing trap which is held between the front two pairs of legs.

These four legs have a dry silk frame strung between them.  Attached to the frame is a net made from sticky elastic silk.  An unsuspecting prey item passing below the spider is in for a nasty surprise.  The spider, connected by a dragline drops and opens the front four legs which extend the net.  It is dropped onto of the victim and when the legs are drawn together again the net closed and ensnares the spiders next meal.  The web is shaken a few times to ensure the prey is completely enmeshed, all the while the spider is wrapping in more silk from the spinnerets and continually biting its prey to inject the venom.  The secured and now deceased prey is held in the palps while the spider feeds and at the same time constructs a new net ready for the next meal to arrive.

Spiders. Rainforests. Costa Rica. Ogre-faced Spider.

The long-legged, long-bodied Ogre-faced Spider

The feature I was interested in were the eyes.  At 1.4mm in diameter, these forward-facing eyes are the largest simple eyes possessed of any land invertebrate.  The eyes have an equivalent camera f/stop of 0.6 which enable them to see very well in dark conditions, the time when the spider hunts.  This, combined with retinal receptors capable of absorbing the smallest amount of ambient light, 2000 x more than other spiders, means they can hunt in, what to you and I, is total darkness.  You can’t see the spider but the spider can see you.  Also, this one was a male as can be seen from the enlarged pedipalps under the front of the head.  These are used during spider mating.

Rainforest animals. Rainforest Spiders. Spiders. Deinopis sp. Ogre-faced Spider. Costa Rica.

Now you can see those eyes and the features that give it the name; Ogre-faced Spider

Weirdness on the Web

It has been a spidery kind of week.  When I was out walking the trails I noticed a small web strung across the path with what I first thought was a small spider removing the papery veil of a Jacaranda seed that had landed there.  In the past I have seen various orb-weavers cutting the silk securing an unrequired piece of material that had land in the web, hold it out with their legs until free of the web and let it drop to the ground.  Not too far down the same trail I saw a similar thing so I decided to take a closer look.  The spider itself was very small and with the naked eye it looked strange, I had not seen this species before and could not quite make out the form.  Something just wasn’t right.

Rainforest animals. Rainforest Spiders. Micrathenidae. Micrathena gracilis. Costa Rica.

Spiny Micrathena hanging from web, viewed from behind

I took several photographs and looked on the camera screen.  The body of the spider was unlike any I had previously seen.  The abdomen, (opisthosoma), was drawn up dorsally and expanded laterally.  It was covered in a series of fleshy, thorn-like protuberances.  I was looking at a Spined Micrathena, (Micrathena gracilis).  During the course of the day I found 3 of these spiders, which is strange because I had never seen this species before.  Later, when back online and researching more information, I learned it is quite common and widespread.  Oh well, new for me and happy to have finally made its acquaintance.

Rainforest animals. Rainforest Spiders. Micrathenidae. Spiny Micrathena. Costa Rica.

Dorsal view of Spiny Micrathena Spider

Only a few meters down the trail from where I photographed the Spined Micrathena I found another web traversing the path at about 6 feet above the ground.  Sitting in the center was yet one more spider that I was unfamiliar with.  I knew it was one of the Spiny-bodied Spiders, of which I have found a variety of different species over the years.  Unlike Micrathena gracilis above, most Spiny-bodied Spiders are brightly colored and elongated with spines and thorns projecting from the body, sometimes giving them an arrow-shape.  I knew this was a Micrathena, the body was long with black centered red spots on a yellow background and with only two more fleshy spines pointing backwards from the abdomen.  Extensive searching failed to produce a name for this species.  So two new spiders in one day and within several feet of each other.

Rainforest animals. Rainforest Spiders. Spiny-bodied Spider. Micrathenidae. Costa Rica.

Strange Spiny-bodied Spider, (Micrathena sp), awaiting identification

Finally I noticed a small web strung not too far above my head in the open garden area.  In the center of the web was a small brightly-colored but very distinctively spider.  The abdomen was vivid lemon yellow with a series of black spots drawn out sideways into an oval shape bearing ferocious looking thorns around the edge.  This was another Spiny-bodied Spider, (Gasteracantha cancriformis).

Rainforest Spiders. Rainforest animals. Gasteracanthinae. Spiny-bodied Spider. Costa Rica.

Spiny-bodied Spider, (Gasteracantha cancriformis)

They are a very common species but are so small that you generally don’t notice them until you walk into the web.  To avoid this situation the silken strands securing the web are flocked with fluffy pieces of silk to make it more obvious to larger creatures.  They come in various color, yellow, white and red being the commonest.  They are very widespread, being found from southern U.S. to northern Brazil and everywhere in-between including the Caribbean Islands.

It is a very short-lived spider; the females die after producing an egg cocoon and the males die a short time after mating.  In certain locations it is another spider that has a reputation it does not deserve.  Some of the native populations regard it as being very venomous.  It is quite harmless.

Philip Davison Is a Biologist, Writer and Photographer Based in Costa Rica

BEETLES: HIDING IN CLEAR VIEW   6 comments


Wildlife, nature, fauna and flora of Costa Rica.

It has been another week of sunny days and rainy nights.  Last month the immediate area experienced almost 28 inches, (706 mm), of rain.  That is approximately 1 inch per day.  However, as to be expected, the pattern of precipitation was not that evenly spread.  There were several nights with really heavy downpours which accounted for a third of the total.  There were more nights when it rained hard but not in a deluge and then there were nights when there was no rain.

Atop Cabo Matapalo, at 500 feet, (150 m), above sea level, there is little chance of flooding, all the water is runoff.  This time of year the ground is saturated so when there is a torrential downpour the water may remain on the surface forming large areas of standing water which quickly drains away.  The creek water level is high and rushes down the channels, falling over rapids, cascades and waterfalls and finally flowing into the sea.  After a night of very heavy rainfall, the creek will have turned murky brown with the volume of sediment it is carrying.  Given a few days of sun the water will have returned to its crystal-clear state, inviting you to plunge into its cooling depths as a relief from the hot and humid atmosphere of the forest.

A Typical Rainy Season Day In The Forest

You wake in the morning, opening your eyes but still not fully conscious.  You had a good night’s sleep, restful and undisturbed, but were brought out of your slumber by a distant roaring sound.  It is still dark outside so what time is it?  Early, pre-dawn, and the roar is heard again, this time joined seconds later by a response, louder roaring but much closer to your cabin.  All of a sudden the roars are echoing around the forest.  To many, the first-time visitors to a Central American rainforest, this could only be large ferocious beasts gathering to collectively do you harm.  To the more savvy, seasoned visitor this is a familiar wake-up alarm call, Howler Monkeys, announcing their location to one another so that different troops can keep their distance during the course of the day.

It did its job as far as you are concerned, you are now fully awake.  The first light of dawn starts to brighten the sky, throwing the form of the trees into dark silhouettes.  Here you are only 8⁰ north of the equator so the dawn twilight does not last for long.  The sun rises rapidly and the grey sky turns blue.  The birds are awake now.  Flying overhead are noisy macaws and parrots heading off from their roosts to the feeding grounds.  Their squawking and screeching is not the most melodious of avian calls.  From within the forest the Chestnut-backed Antbird, Black-hooded Antshrike and the Bright-rumped Atilla are some of the first choristers to greet the new day.   The males are vocally drawing up the bounds of their territories.

It is after breakfast and the sun is now high in the azure sky.  The temperatures have rapidly risen from the cool chill from when you opened your eyes.  The air is still.  You grab your camera and head off into the shade of the forest.  The only sound is that of cicadas, their loud calls increasing in intensity, volume and pitch as the morning progresses.  Here and there from different points in the unseen depths of the forest, obscured from your vision by the trunks of the trees are more birds calling.  The familiar “Who cooks for you” of the Short-billed pigeon, the high-pitched squeaky call of the Black-mandibled Toucan, it sounds more like a rusty pulley that needs oiling than the call of a bird.

You see many things close at hand to photograph, flowers, fruit, a beetle, a praying mantis, small frogs and lizards.  Up above you the Spider Monkeys put on an impressive display of acrobatics as they swing through the tree tops.  You can’t miss Spider Monkeys with their high-pitched chattering and high-energy crashing through the tree tops.  This is in complete contrast to the languid slow moving and deeply voiced Howler Monkeys.  You come across a troop of White-faced Monkeys, more leisurely in their pursuit of a meal.  You see them peeling away bark and turning leaves, always gleaning, looking for the small creatures that make up the bulk of their diet.

It is approaching midday.  The sun is directly overhead.  Despite being beneath the shade of the canopy, the temperatures have risen dramatically.  Combined with the high humidity, conditions have become like those in a well stoked sauna.  If the air was still outside the forest, within its confines there is not a breath of air.  The sweat is rolling down your face and your clothes are now soaked.  Thankfully you brought a lot of water with you and a packed lunch.  Time to take a break for some respite in order to recover you waning energy levels.

As you sit, taking in the sounds around you, a rumbling can be heard off in the distance, thunder.  You finish your sandwiches, take a swig of water, pack everything into your bag and head off down the trail once more.  You stop to photograph a line of Leaf-cutter Ants.  You need to get close to the ground and have some patience to capture the individual caste members.  You are rewarded a little later with a swarm of Army Ants, incessant in their drive forward flushing out non-flying arthropods.  They are accompanied by a mixed flock of ant-birds, woodpeckers, woodcreepers and Grey-headed Tanagers, all in a heightened state of excitement as they feed on the flying insects driven out of hiding by the Army Ant assassins.  Lots of photographic opportunities here.

It is now much later; the almost unbearable temperatures have dropped and the sun is sinking fast towards the western horizon.  Also, that rumbling is getting louder and the sky is rapidly darkening in the east.  You have filled your memory card with images so it may be astute to pick up the pace now and head back to base.  Before too long a breeze picks up and the tree crowns begin to sway.  Loose leaves and small twigs come tumbling down from the canopy.  It is rapidly darkening and the breeze becomes a wind.  The trees are now swaying more violently and you can hear branches being snapped and crashing down.  All of the monkeys start to shriek in objection to their homes being shaken in this manner.  The advancing storm has no ears and cares not for their protestations. Light rain begins to fall.

Within a shorter time than you would have liked, the sky above you has turned black.  The rumbling thunder has become loud and explosive, now accompanied by almost instantaneous flashes of lightning.  The rain comes out of the heavens with an ever-increasing intensity.  The canopy is being lashed.  Leaves and branches are torn from the trees by the sheer weight and force of the water being poured upon them.  Lightning is cracking and fissing around you, the storm is immediately overhead, these are thunderflashes and this is not a safe place to be.  The path at your feet which moments earlier was soft and damp is now a running river albeit only a couple of inches in depth.  The question is should you stop and find shelter or should you persevere on.  You chose the latter option.

Your step quickens, not too fast as you don’t want to slip and fall.  You hear a sharp crack above you, then a loud snap and a huge branch comes tumbling with force through the understory.  It hits the ground so hard that it stands upright as if it had been planted.  The flashes are lighting up the whole sky in a blinding white light.  Each boom of thunder causes you to flinch.  It is raining so heavily that you can barely open your eyes due to the stinging pain it causes you.  But you are almost there, the path out of the forest is up some stairs and around a bend on the trail.  The steps are now a series of cascades but the tumbling water does not hinder your stride.  You will soon be back in the dry comfort of your cabin.

Just as you step out of the forest and into the open garden area, the driving rain suddenly subsides to that of a light summer shower.  The black sky starts to lighten and the deep rumbles roll off into the distance.  Each flicker of lightning is still causing flashes but now over on the horizon.  Thankfully you had the foresight to pack all of your equipment into a waterproof camera bag before the deluge descended and it seems to have served its purpose well.  The rain becomes drizzle and finally peters out then stops.  The sky is now pale grey and the sun sinks to the point where the final rays light up the underside of the clouds in a deep orange.  You have just experienced a typical September day in a Costa Rican rainforest.

Beetles Hiding In Clear View

Beetles, there are thousands of species and yet if you go out with the intention of finding them you may become aware very quickly that they are not as obvious as you have thought.  Turning over rocks or peeling rotten bark from fallen trees may produce one or two species but nothing in profusion.  That is why when I head off into the forest it is never with the purpose of photographing anything specific, not unless I have seen something that I wanted to return to.  Some people go out having birds or mammals as their goal, I am always looking for smaller things, as regular readers of the blog will already know.  The camera will have my favorite 105mm macro lens attached and will be set to take photos of all manner of mini beasts in darker conditions.  The shots will be hand held as I only take the tripod if I have a certain subject in mind.

Last week I found two different species of beetle out in the open aspect of a sunny forest edge.  They were in separate locations but within the same area.  They were both sitting on top of a leaf, in bright sunshine and would not stay still.  I had to keep maneuvering around the subject to try and get a decent image.  Every time I had things set, they would turn their backs to me and wander off along the opposite length of the leaf.  Finally, after much repositioning, I managed to obtain some acceptable photographs.  One of the problems with photographing beetles is the hard, smooth and glossy exoskeleton that many of them have.  It reflects the light from the flash gun.  To obtain the depth of field that I prefer, with a moving subject I have to use very small apertures and by necessity I need to add extra light with flash.

The first beetle is a Pleasing Fungus Beetle, (Cypherotylus asperus), in the family: Erotylidae.  I am not sure why they are pleasing but fungus beetle refers to their main dietary item which may come as no surprise, fungus.  The bright red blotches against a black background is aposematic, or warning coloration.  If molested or attacked, the Pleasing Fungus Beetle emits a foul-smelling odor that would cause most would be predators to back off.

Rainforest animals. Rainforest insects. Rainforest Beetles. Coleoptera. Erotylidae. Cypherotylus asperus.

Pleasing Fungus Beetle, (Cypherotylus asperus)

The second beetle is a Leaf Beetle in the family: Chrysomelidae.  They typically have the domed body, clubbed antennae and are multi-colored.  But as there are almost 50,000 species in this family I have, so far, been stumped as to which species this is.  Should any beetle expert be reading this and would like to provide a name I would be most grateful.  The clue to the diet is once more in the name.  They feed on the leaves of a variety of vegetation.

Rainforest animals. Rainforest Insects. Beetles. Coleoptera. Chrysomelidae.

Leaf Beetle, (Chrysomelidae sp)

The Earth Moved

Walking through the forest you can often have your attention momentarily attracted by some small movement down in the leaf litter.  It may be ants, spiders, lizards, frogs or a myriad of other small creatures that live concealed beneath the carpet of rotting leaves.  It is the tread of your footfall that will disturb them and have them run for cover out of harm’s way.  Depending on the speed of the animal you may lose sight of it very quickly.  Some move from leaf to leaf.  Generally if any of these litter living denizens gets below the leaves it will be gone and unless you are lucky you will just have to imagine what you saw.  Occasionally though one will freeze when exposed to the light.  Last week, my size 13 boot thudding into the ground caused a tiny frog to jump out of the imminent descending disaster.

There are several small frogs that inhabit the dark and damp environment of the forest floor.  The squat body shape of this one revealed its identity almost immediately.  It was one of the rather delightfully named dirt frogs, this one being a Stejneger’s Dirt Frog, (Craugastor stejnegerianus).

Rainforest animals. Rainforest amphibians. Frogs. Anura. Craugastoridae. Craugastor stejnegerianus.

A tiny Stejneger’s Dirt Frog, (Craugastor stejnegerianus)

The dirt frogs are totally terrestrial frogs, they live their whole life on the forest floor and never need to go to water as many amphibians do.  They still have moist skins through which they largely breath and therefore by necessity can’t leave the confines of the damp environment under the trees.   There are several species that live in this area and Stejneger’s Dirt Frog is one of the commonest.

They belong to the family: Craugastoridae or the Fleshbelly Frogs.  Typical of this family is the reproductive habit of direct development which negates the necessity of them having to return to water to reproduce.  The frogs pair up, (I can’t say I have ever heard these frogs calling), and the female lays her eggs amongst the leaf litter on the forest floor.  There are only about 20 – 30 eggs but they are fairly large in comparison to the adults.  The egg is packed with yolk and the tadpole develops within the egg, there is no free-swimming tadpole stage.  After about 8 weeks a tiny copy of the adult emerges.

Rainforest animals. Rainforest amphibians. Rainforest Frogs. Anura. Craugastoridae. Craugastor stejnegerianus. Osa Peninsula. Costa Rica.

Dorsal view of Stejneger’s Dirt Frog, (Craugastor stejnegerianus)

As you are walking through the forest, if you keep your gaze lowered scanning the ground then you will surely see a small piece of the earth move.  Given closer inspection then you will probably find you are looking at a dirt frog.  But take a photograph as they are not always easy to identify.

Fying Dragons.

A few weeks ago I managed to photograph a dragonfly with black bases to the wings, a Black-winged Dragonlet, (Erythrodiplax funerea).  This week I managed to capture another dragonfly but with the inverse situation of having black tips to the wings, the Large Woodskimmer, (Uracis fastigiata).  This one was found in a different area to the previously mentioned species but they had been there for several weeks.  This species was found in secondary forest, in a light gap and always close to the ground.  Once again my attempts to take a picture were always doomed to failure because every time I lifted the camera to my eye, they would fly off.  But as we know with photography patience is a virtue and finally after several weeks I got lucky.  This one stayed still long enough for me to get several pictures.

Rainforest animals. Rainforest Insects. Dragonflies. Odonata. Libellulidae. Uracis fastigiata

Large Woodskimmer, (Uracis fatigiata)

Unlike the dragonflies which can be found in open sunny locations around a body of water that have fast flight and hover, these forest species seem to be more sedentary and perch on low vegetation and only seem to move if disturbed.  Having excellent eyesight adapted to detect movement it does not take much to disturb them.  It could be that they are sit and wait predators just diligently watching for the right sized meal to pass by before taking off to capture it.

Philip Davison Is a Biologist, Writer and Photographer Based in Costa Rica

Sun and Moon, Bananas and Lichen.   2 comments


Philip Davison. Costa Rica. Blog. Nature Diaries

Sunny September

The clement weather conditions are continuing to prevail.  The rain we are receiving is most certainly intense but by no means prolonged.  If there is one day of rain it is being followed by two days of sun.  This time of year there are very few visitors.  September and October are not big holiday periods.  For anyone who does want to visit Costa Rica at this time of year you can certainly avoid the crowds but you also run the risk of being confined to your cabin unless you want to suffer a constant soaking.  For those of us who do live here then the quiet time and unseasonably dry and sunny conditions give us time to go and explore a little more or in my case catch up with the writing.

I’m Lichen That

One night when I was out doing my nightly frog counts I came across one of the Anolis lizards that I see more often up in the canopy, a Lichen Anole, (Anolis pentaprion).  This individual was sleeping but when I turned the lights on to video the creature in its state of slumber the instant change from night to apparent day woke it.  Not only did the lizard stir but the increase in light levels drew in some of the insects including one of the few species of night-flying wasps, Apoica pallida.  It landed near the lizard’s head so presenting itself as an easy meal the advantage of which it was not going to refuse despite having only just being disturbed from its sleep.  With a quick snap of the jaws the wasp was caught, chewed up and down the body and then swallowed.  The Anolis then soporifically walked up the small branch on which it was clinging, climbed atop a leaf into a darker location than it was now finding itself, closed its eyes and went back to sleep.

Anolis lizards are a very diverse genus with many closely related genera belonging to the family: Polychrotidae.  There are well over 200 species of Anolis and each species quite often is divided into a number of subspecies.  Anolis lizards are similar to geckos in that they have an anatomically specialized structure to the toes, (lamellae), that allow then to climb with ease including smooth vertical walls and even panes of glass.  Anolis lizards are generally small and unless you notice some movement as they jump through the vegetation then they can easily be overlooked.  In terms of ecology smaller species inhabit the lower levels of the forest and conversely larger species the higher levels.

Anolis pentaprion

Lichen Anole

Although the family is species rich, it is not always easy to identify the individuals to species level.  One factor that does help is the males have a loose flap of skin under the chin called a dewlap.  Thankfully each species has a different color dewlap, particularly pronounced in this area.  The loose skin is attached to a rod of cartilage fixed at the jaw over which the lizard has muscular control.  The lowering of the cartilage extends the skin revealing the brightly colored flag which is in stark contrast to the more usual body color and it is used to intimidate and scare rival males from the territory or used to court females.  Certainly if you see that bright flash of color appear as if from nowhere then there will be a second individual you may not be so aware of but it will be somewhere close by in the vicinity.  The dewlap of the Lichen Anole is a deep purple edged with magenta and is not as large as in some other species.  Most females do not possess a dewlap and because there is a strong sexual dimorphism can prove a little more difficult to identify.  Here on the Osa Peninsula there are only seven species of Anole and they are all fairly distinct in appearance both male and females.

Many Moons

There are two particular species that seem to have reacted to this year’s slightly abnormal weather conditions.  One is a butterfly and the other is a frog.  They have both been recorded in numbers in excess of those normally found.

The Luna Satyr, (Pierella luna), is a largish brown butterfly that is normally found throughout the year but for the most part as solitary individuals or in small groups.  It is found flying very close to the forest floor in the dark, dank, shady conditions beneath the forest canopy.  You will quite often only notice it when it momentarily passes by your feet, wings beating slowly, as it moves from one side of the path to the other.  It will disappear under the vegetation and when it settles the muted grays and browns of its now still wings blend it immediately into the background.  It prefers the denser aspect of secondary forest as opposed to the more open situation beneath primary forest.  This may have something to do with the distribution of its larval host plant, species in the family: Heliconiaceae, many of which can be found in secondary forest habitat.

This year when walking along trails through secondary forest Luna Satyr could be found in huge numbers much larger than experienced before.  I am not sure what triggered the population explosion but the adults have not been hard to find, sometimes in groups numbering ten or more.  The slightest disturbance caused by your footfall will have them momentarily take to the air before quickly alighting once more on the ground.

Pierella luna

Luna Satyr

A Big Bunch

The Banana Frog, (Dendropsophus ebreccatus), is one of those small tree frogs that you can more or less guarantee you will see if you go to the pond at night.  They are ever present throughout the year.  At the height of the amphibian breeding season which starts when the rains arrive in April, gets into full swing in May and draws to a close by the end of August, the Banana Frog males can be both seen and heard in reasonably large numbers every night.  Those numbers reduce outside of the breeding season to the point where during the dry season it might only be one forlorn male out calling but there will always be one.

The males emerge as the sun slowly sinks beneath the western horizon.  They set up their territories on the Water Lettuce or Water Hyacinth and call vigorously with a protracted “Eeeack”.  The larger egg bearing females emerge a little later, select a male on the quality of his call, makes her way over to the male of choice, they pair up and later she lays a sheet of small jelly coated eggs on the surface of a leaf which the male fertilizes.  The eggs develop here for 7 or 8 days, the tadpoles wriggle free and slip below the surface of the water from where they will emerge about 8 weeks later as small froglets.

Whereas this time of year when all the other frog species have either disappeared from the breeding pond or are present in only small numbers, the Banana Frog has seen a surge in numbers.  There are presently in the region of 20 calling males every evening.  It could well be that they are taking advantage of the lack of competition from other species, although there are not too many other species that do use the Water lettuce, (Pistia stratiote), and Water Hyacinth, (Eichhornia crassipes).  The tadpoles of other frogs do have to compete for space and food once they have entered the water, some of which may be larger and/or more voracious than D. ebreccatus tadpoles.  It may simply be the fact that there is still a lot of rain which is perfect for the eggs but that is the norm every year.  Whatever the reason if you could down to the pond at the minute after sunset you will be greeted by a vociferous chorus of amorous Banana Frogs.

Dendropsophus ebreccatus

Banana Frog

Seeing You Walk for the First Time

Last week I happened across an insect that has proved to be somewhat difficult to identify.  What initially caught my eye were the colors, most strikingly the bright yellow.  The head was small but the body was long and soft.  The wings too were brightly colored but in green.  My first thoughts were that it was some kind of Phasmid or Walking Stick, more precisely a winged walking stick.  It did not seem to be disturbed when I moved it from the bare white stucco wall where its colors were making it rather conspicuous to some nearby vegetation where it was less obvious.  Not moving is part of a Phasmids game plan though.  I took some photos and headed off to my reference library.

Phasmid

Winged Walking Stick

As with most insects that I see for the first time after 16 years of living here I just know the identification is going to be difficult.  Insects are so prohibitively numerous in number of species, especially tropical insects.  The reference material available is limited and by no means exhaustive.  So after some searching I was not really any further forward than still being confident it was a winged phasmid.  Time to scour that great resource the internet.  Scrutinizing photo after photo all I could conclude that it was a winged phasmid but there was nothing I could see that looked remotely like this individual.  So if there are any phasmid experts that may be reading this and could enlighten me as to a genus or species I would love to hear from you.

Phasmid

Winged Walking Stick

Philip Davison is a biologist, writer and photographer based in Costa Rica.

 

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