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Phasmids: A Neotropical Walking Stick   Leave a comment


Wildlife, nature, fauna and flora of Costa Rica.

Sticking to the Twigs

There are some animals that live out in the open, right in front of your eyes, and yet you never see them.  That is because they don’t want to be seen.  Only when mistakenly they venture forth onto a background that reveals their presence will you have the opportunity to marvel at their disguises.  One such group of animals are the Phasmatodea, more commonly known as Walking Sticks or Stick Insects.

Last week I saw one that had made such an error.  It had left the vegetation where it lives perfectly concealed from view and had wandered onto the screen of my cabin.  There it stood out like a sore thumb.  Thankfully for the phasmid it was my eyes that saw it before those of any potential predator.  If removed the unfortunate creature and placed it back amongst some twigs from which I could take its picture but also from where it could make its way back into the obscurity of the vegetation.

Phamatodea: Walking stick in Costa Rican Rainforest

The long spindly legs and body of a Walking Stick make enable it to avoid the attention of predators

The body and legs of the walking stick are long and spindly.  They are either green or brown in color and quite often, as this one was, a mixture of the two.  The body and legs are grooved and have small thorns.  They resemble so perfectly a twig that, even when you are looking directly at them, they are imperceptible.  Some species have wings but not the one I was looking at.  They are vegetarian and tend to be host specific.  Walking sticks reach the zenith of their diversity in tropical forests such as these, of the 2,500 species identified so far, 30% live in the Neotropics.

As well as the perfectly camouflaged body form the phasmids use other means by which to complete the illusion.  This one, when disturbed, would rock back and forth as a twig being blown in a breeze.  Then it would freeze and hold the front legs as well as the long filamentous antennae out in front of its head to make to enhance its long twig-like form.

In and Out of the Rainbow

There has been a new wave of plant life that has come into bloom over the past week or so.  The cycle of change in the forest is such that throughout the year you are never short of something new to see or hear each time you venture out onto one of the trails.  As the flowers of certain species turn to fruit, then so do others come into bloom.  The flowers and fruit provide a continual annual transition of color and form.  You only have to keep your eyes open as you walk and you will be rewarded with a visual sensory feast.

Last week one of the most obvious additions to the floral display was the Recadito, (Palicourea guianensis) of the family: Rubiaceae.  The multi-clustered bright yellow flowers are borne on a vivid red stalk at the end of the branches.  They are visited a lot by butterflies, especially if found growing at the forest edge.  It is a small tree with large leaves and is reasonably common in wet habitat from Mexico to Bolivia.  There are 27 species of Palicourea to be found in Costa Rica, 3 of which occur on the Osa Peninsula.

Rubaceae of the Osa Peninsula, Costa Rica.

The distinctive floral display of Recadito, (Palicouria guianensis)

Another related plant, but much smaller and subtler is the Cafecito, (Psychotria capitata).  It too, belongs in the family: Rubiaceae but it is a very large genus, 115 of which live in Costa Rica, 40 of those on the Osa Peninsula.  They are not always easy to identify to species level.  This one, Psychotria capitata has small white flowers which when pollinated give rise to small purple berries.  At that point it resembles a rather swollen blackberry fruit.

Cafecito, (Psychotria capitata), Osa Peninsula, Costa Rica.

Delicate white flowers of the unobtrusive Cafecito, (Psychotria capitata)

Crosier for a Green Bishop

Ferns, or pteridophytes, are non-flowering vascular plants that most people who enjoy walking in the countryside will be familiar with.  You will not see fruits or seeds as ferns produce tiny dust-like spores produced in special spore cases on the underside of the leaves.  There are about 800 species of fern in Costa Rica but their form is so distinctive that they are not too difficult to recognize as such.  They are mostly low growing in shady areas of the forest but there are some that grow to a substantial size, the tree ferns.  These behemoths of the pteridophyte world, along with the cycads, were the dominant form of terrestrial vegetation before flowering plants evolved, and can be regarded as the “Food of the Dinosaurs”.

There are tree ferns found growing in these forests but they don’t reach the giant statures of those in other parts of the world.  Most of the ferns here are of the low growing type.  When a new leaf is produced it lies in the center of the plant, wound around itself like a green rope on a spool.  As the days pass it unfurls up and outward, revealing leaves that appear as an organic fractal, repeating the pattern on a smaller and ever smaller basis.  Eventually as the stalk has reached its maximum growth, the final part resembles a Bishop’s Crozier, which ultimately uncurls and the side-branching leaves and leaflets open out to reveal the familiar frond.

Pteridophytes of the Osa Peninsula, Costa Rica.

An unfurling fern frond

Mustachioed Murderer

Walking through the forest I entered a more open spot where the sun was lighting up a clearing.  I noticed something move very quickly on the forest floor.  It settled on the surface of a leaf.  I knew what it was but to begin with I was a little puzzled as it looked to possess four large eyes, so in my mind I was looking at one insect perched on top of another.  I bent down to take a closer look and I could now see my mistake.  There were most certainly two very large distinctive eyes but the dark markings contrasting with the yellow ground color of the thorax gave it the appearance of a second insect sitting on its back.  I could now also confirm my identification as that of a Robber Fly, family: Asilidae.

Robber flies are true flies of the order: Diptera and therefore only possess one pair of wings.  A distinctive feature of the robber flies is the cluster of hairs at the front of the head that give them a look of an Edwardian gentleman sporting a rather luxurious mustache.  This is known as a mystax, which is taken from the Greek word for mustache.

Why would a fly have a protective mustache of bristles protecting the front of the head?  The Robber Flies are accomplished predators and will hunt down any arthropod of a suitable size, not too small, not too large, that makes the unfortunate mistake of entering into the killer’s field of view.  The Robber Fly has large eyes and respond with speed to a potential meal.  It uses the stiletto-like piercing mouthparts to stab its victim and to inject a saliva which contains a deadly cocktail of neurotoxins and cell destroying enzymes which render the prey to a corpse being digested from within.  The fly then sucks out the pre-digested meal.  They have no hesitation in attacking wasps and ants which themselves are capable of inflicting a fatal bite or sting.  The mustache serves to protect the fly from such retribution.

Asilidae: Robber fly on the Osa Peninsula, Costa Rica.

Assassin with stilleto ; Robber fly with cockroach prey

Robber Flies prefer sunny gaps in the forest, which is exactly where I found this one.  They sit on a perch located low to the ground and wait for a meal to pass by.  Their reaction speed is so fast that in a blur of the eye they can snatch a flying insect out of the air.  You can see in the photograph that this one had just caught a tropical cockroach.  Don’t try to catch one in your hand as a stab from that proboscis is very painful.

There are about 7,500 species of Robber Fly distributed around the planet, preferring warmer areas that are arid or receive only seasonal rainfall.  They are not that hard to find, pick a sunny light gap and then you just have to sit and watch for that quick movement.

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

An Orgy of Green Pain   6 comments


Philip Davison Nature Diaries. Bosque del Cabo Rain Forest Lodge.

Parachuting into an Orgy

The past week has been a mixture of sun and rain.  The days have been gloomy with heavy, brooding overcast skies.  Occasionally the clouds part and the sun has shone down to light up the shadows.  But the menacing grey blanket that covering the area from north to south and east to west always threatened to unleash a downpour.  Sometimes the drizzle filled the air from dawn to dusk but you knew there was more to come.  By late afternoon the light rain would turn to heavy and by the time the sun had set below the horizon then the heavens would open drenching one and all.

The amphibians have been enjoying the onset of the rainy season, their numbers increasing over the last month but these more persistent nightly deluges have had the frogs collecting in huge numbers and rejoicing in a reproductive frenzy.  One frog that responds to torrential rain is the Parachuting Red-eyed Green Tree Frog, (Agalychnis spurrelli).

Agalychnis spurrelli. Hylidae. Pseudomedusinae.

Parachuting Red-eyed Green Tree Frog, (Agalychnis spurrelli)

One evening, just after sunset it started to rain heavily and by next morning we had experienced 11 inches of rain.  That was the trigger that stimulated hundreds of Parachuting Red-eyed Green Tree Frogs to leave the canopy, which is where they reside out of view, and launch themselves into the air.  This frog has a uniformly colored dark mossy green upper side.  Its flanks are a pale lemon yellow.  It has large heavily webbed hands and feet of the same buttery hue and, of course, it has the large red eyes.  As they leap out of the canopy they spread the fingers and toes so the webbing is stretched tight, quite literally into a parachute of living tissue, which allows the frogs to glide down to the vegetation surrounding the pond without ill effect.

Each male quickly establishes a territorial perch from which he begins to call in an attempt to entice an egg-laden female his way.  The call is a short, soft, almost electronically-sounding sound.  Selecting a male on the quality of his call, the deeper the sound the better, the female makes her way over to the chosen chorister, he jumps on her back and they set off to visit the pond.  The female absorbs water through her skin and fills her bladder.  Now the female, not only with a body full of eggs but also carrying the male on her back, makes her way to a deposition site.  She chooses a broad leaf overhanging the surface of the pond and she commences to lay a sheet of eggs across the leaf.  At the same time as she releases the eggs from her body the male fertilizes them.  This normally take place just before daylight.

Parachuting Red-eyed Green Tree Frog. Osa Peninsula. Costa Rica. Philip Davison.

Parachuting Red-eyed Green Tree Frog Eggs.

As dawn breaks and the sun rises, the frogs have to get out of the light and into the dark as quickly as possible.  They don’t have time to get back to the canopy, parachuting down was a quick descent but the ascent involves a 100 foot climb and there is little time.  The sun continues to steadfastly climb in the sky.  Hundreds of frogs are now scrambling desperately to escape the skin-drying effects of its harsh rays.  This was the point at which I arrived, just in time to see countless small green goblinesque figures running along branches in a desperate effort to find a not already fully accommodated shelter.  I was not the only one.  A Bare-throated Tiger Heron had found itself an early morning breakfast bonanza and was picking off the unfortunate amphibians one after the other.

The larvae will develop in the eggs for about 7 or 8 days before the gelatinous mass liquidizes and the wiggling tadpoles drop into the pond water.  There they will complete the tadpole stage and if they make it through the aquatic stage will finally emerge after 7 or 8 weeks as a tiny froglet which will eventually have to make its way to the tree tops.  The Parachuting Red-eyed Green Tree Frog is an explosive breeder and these episodes can only be witnessed following those biblical-like rain storms.

Agalychnis spurrelli. Bosque del Cabo.

Parachuting Red-eyed Green Tree Frogs After Sunrise

Showing Off in the Green Room

The forest flora can be flamboyant and gaudy or subtle and subdued.  The blooms may appear abruptly in a visual feast or occur in small numbers isolated and hidden in the dark green depths the subcanopy.  Some plants flower but once a year, a spectacular show drawing the eye like a beacon which is setting the tree tops ablaze and illuminating the forest canopy in a patchwork of color on natures silvian canvas.  It is no wonder that the largest percentage of insect life resides and thrives at the tree tops.  Here you will find a kaleidoscope of dancing butterflies waltzing from bloom to bloom in search of the energy rich nectar, so vital in allowing these ephemeral beauties to complete the final stage of their short adult lives.  Other plants may flower continuously throughout the year but only producing one or two blooms at a time.

It is not just the butterflies that rely upon the flowers.  Many other insects are attracted by their rich colors and evocative scents.  The plants will sometimes target birds or mammals to do their bidding.  The plants offer the animals rewards but there is method to their bribery.  These are windless forests; a zephyr is the strongest a current of air that will move through the trees.  Pollen needs to be transported from one plant to another in order for the plants to reproduce.  It helps if the plant can target and reward a specific agent to enable its pollen to be deposited in the flower of the same species.

The plants cannot rely on wind for seed dispersal either.  Once more they have evolved the means by which to encourage animals into becoming innocent vectors of transfer and movement of the seeds that will potentially give rise to the next generation.

Over the last week as I was walking along the paths through the forest I could see some of those secretive flowers blooming in the shadows as well as some bright vivid forms, their colorful flower heads breaking up the somber borders of the trails.  One of the more subtle blooms was that of the Spiral Ginger,  (Costus scaber).  The flowering head is a rather stout, deep red spike composed of bracts, each of which will produce a bloom.

Costus scaber. Costaceae. Osa Peninsula. Costa Rica.

Spiral Ginger, (Costus scaber)

The fiery orange, yellow-tipped flower sticking out of the bract attracts in hummingbirds which are the principal pollinator of this species.  The colors red, orange and yellow are commonly used by plants to attract hummingbirds, these being the colors in the spectrum that are complementary to the background green of the leaves.  These are also very hot colors whereas green is a cool color and so they readily stand out, particularly to animals that have keen color vision such as birds.  The hummingbirds hover in front of the flowers and probe within searching for the nectaries.  As they do so, the head and bill pick up pollen from the anthers which is transferred to the stigma of the next flower it visits thereby effectively pollinating the plant.

The family Costaceae is closely related to the ginger family: Zingerberaceae.  Most gingers are Asian but there are some gingers native to the Neotropics.  Most costas are American but there are some costas that are native to Asia.  There are 23 species of costa native to Costa Rica, 14 of which are found on the Osa Peninsula.  As they all look similar it is not too hard to identify them as costas but it is a little more difficult to identify them to species level.

Queen of Pain

Insects are fascinating creatures to photograph.  Once you have downloaded the image and zoom in, as long as the picture is in sharp focus, then the body form and colors become compelling.  All of the joints, the body plates and the detail of the head and wings will keep the naturalist mesmerized.  You can conjecture as to the function of all those different hairs and how the body parts articulate.  Not only that but how does the creature live, what is life history and what are the multitudinous, complex interconnected threads that tie it into the ecosystem of its habitat.  Insects complete their lives in almost as many ways as there are species.  Many insect’s lives are a mystery to us, we simply have no idea how they get from egg to adult.  That is not surprising as there are more species of insect on the planet than any other group of animals.  Because we don’t know, then that makes us more eager to study and discover more information to unravel those mysteries.

One groups of animals, the Hymenoptera, bees, wasps and ants, provide an endless source of material for research.  Many of them have well documented life histories and they work to a general pattern but there are variations.  I saw this wasp guarding its brood in a nest under a leaf in the tropical garden.

Although the wasp appeared to be alone, it was one of the social wasps belonging to the family: Vespidae.  The nest is made of carton which is a chewed up fibrous vegetable material, quite often wood, which forms the cells into which the eggs are laid.  The egg hatches and the larva develops, growing rapidly on a diet of chewed up insect prey captured by the queen.  The queen only uses her sting for defense, the prey is caught and chewed-up in the mandibles.  A pale larva lacking in pigment, can be seen in one of the cells.   When the larva pupates, the entrance of the cell is capped by a carton lid from which a new adult will emerge sometime later.

Polistinae sp. Hymenoptera. Vesperidae. Polistinae.

Paper Wasp Queen on Nest, (Polistinae sp)

There were, in fact, two wasps sitting on the nest.  This suggests that they belong to the subfamily: Polistinae.  These colonies consist of one or two queens both of which are responsible for the construction of the nest and raising the offspring without the aid of other workers.

Even if nobody told you, then you would learn very quickly from painful experience to leave wasps alone.  The black and yellow coloration of bees, wasps and hornets is the most visible of all color combinations.  As I have already mentioned, the wasp does not use its sting to subdue prey but rather uses it to defend itself.  But, as in many cases, it is better to use a deterrent rather than become involved in a physical battle where even though you may win, the probability is that you will sustain some damage yourself.  To ward off any potential threat, the wasps use threatening coloration.  It does not take too many painful encounters before most creatures would learn to avoid anything sporting that vividly distinctive black and yellow.

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

Butterflies of Matapalo   2 comments


Philip Davison Nature Diaries. Bosque del Cabo Rain Forest Lodge.

Life as Normal

Last week we had the continuing alternation of sun and rain.  The frogs are still out in force, in fact several new species have joined the nightly chorus of amorous males.  The significant newcomer that has appeared in ever increasing numbers has been the Mexican White-lipped Frog, (Leptodactylus fragilis).  This species typically calls from the damp ditches very close to the pond but it is heard more often than it is seen.

Butterflies Abound

The clement weather conditions have allowed the late start to the butterfly season to persist until later in the year.  Last week there were some very bright, sunny, clear blue skies which is always good for butterfly watchers, particularly if the nectar producing plants are in flower.  The butterflies did not disappoint and came out in force.

Many of the bright, gaudy butterflies seen flying around the grounds belong to the family Nymphalidae.  This family of butterflies is found all over the world except Antarctic.  They are known as brush-foot butterflies due to the front two legs being reduced in size and covered with hairs.

The bright sunny conditions make it problematic to take pictures of the butterflies because of the high light levels and the fact that they are very active.  A flowering nectar plant provides the best opportunity in these situations as you can pick one blossom and invariably it will be visited by a succession of individuals.  In one of the tropical gardens a blooming Lantana camara was providing that opportunity.

Two fast flying vivid orange butterflies, the Gulf Fritillary, (Agraulis vanillae), and the Iulia Longwing, (Dryas iulia), settled momentarily.  They are both members of the subfamily: Heliconiinae.  The Heliconiinae, except for a few species, are confined to the Neotropics where they proliferate in diversity.   The caterpillars of this subfamily typically feed on passion vine and hence are commonly known as passion vine butterflies.

Agraulis vanillae. Nymphalidae. Heliconiinae.

Gulf Fritillary

The leaves of the passion vine larval foodplant contain cyanide in the form of a cyanogenic glycoside.  The caterpillars have an enzyme that allow them to sequester the cyanide molecule which serves to protect them from being eaten.

Dryas iulia. Nymphalidae. Heliconiinae.

Iulia Longwing

Another related butterfly landed close by, the Zebra Longwing, (Heliconius charitonius).  I have been trying to take a decent photograph of this butterfly for some time but it just will not stay still.  I managed to get an image but not the best.  Two more heliconiids were flitting from flower to flower, the Postman, (Heliconius erato), and the Hecale Longwing, (Heliconius hecale).

Heliconius charitonius. Nymphalidae. Heliconiinae.

Zebra Longwing, (Heliconius charitonius)

The adult heliconiids, just as the larval stage, use chemical defenses in the form of cyanide.  The adults feed not only on nectar but also pollen.  Pollen is nitrogen-rich and this allows the adult butterflies to produce cyanide which is stored in the body.  Having a chemical defense is not effective if the predators are unaware of it.  To that effect the heliconiid adults advertise themselves using brightly colors, the color groupings of which the predators quickly learn to associate with a foul-tasting meal which they will ignore in the future.  This is known as aposematic, or warning, coloration.

Heliconius erato. Nymphalidae. Heliconiinae

Postman, (Heliconius erato)

But that aposematic coloration lends itself very well to two forms of mimicry.  Non-poisonous butterflies mimic poisonous butterflies which is known as Batesian mimicry.  Also, many poisonous butterflies are co-mimics of one another in a series of mimicry complexes known as Mullerian mimicry.  Mimicry really does work and quite often it takes a stationary butterfly and a trained eye to distinguish one species from another.

Heliconius hecale. Nymphalidae. Heliconiinae.

Hecale Longwing, (Heliconius hecale)

One other nymphalid that was flying around the Lantana was a small Theona Checkerspot, (Chosyne theona).  These butterflies tend to have bold orange and yellow markings on a black background earning them the name checkerspots.  Many of the checkerspots exhibit variations largely due to environmentally sensitive temperature changes.  Just as their heliconiid cousins, they would appear to be distasteful to birds which will avoid feeding on them.  I quite often see them in open areas flying very close to the ground.

Chlosyne theona. Nymphalidae. Nymphalinae.

Theona Checkerspot, (Chlosyne theona)

The forest too provided a couple more nymphalids, the Blue-grey Satyr, (Magneuptychia libye), on the ground and the Sunset Daggerwing, (Marpesia furcula), higher up in the vegetation.  The Sunset Daggerwing was a species that I really wanted a good photograph of as it is quite exquisitely colored.  The males are the most striking but this was a female.  After watching it fly back and forth along the vegetation bordering the path it finally settled beneath a leaf only six feet off the ground which gave me the opportunity to get the picture.  Fortunately it opened its wings several times which enabled me to capture the dorsal and ventral surfaces of the wings.

Magneuptychia libye. Nymphalidae. Satyrinae.

Blue-gray Satyr, (Magneuptychia libye)

Marpesia furcula. Nymphalidae. Biblidinae.

Sunset Daggerwing, (Marpesia furcula)

Sunset Daggerwing. Philip Davison. Felipe del Bosque.

Sunset Daggerwing, (Marpesia furcula)

One final forest butterfly that settled in a position not too far above my head was a cattleheart in the genus Parides.  These are not the easiest of butterflies to identify in the field, especially in subdued lighting and with the wings closed.  They are all a deep velvety black with the markings on the upper surface of the wings being yellow bars and red spots.  It is these markings that help identify them to species level but even these features can be variable and confusing.  I am almost sure that this was a male Wedge-spotted Cattleheart, Parides lycimenes, but not 100% sure.

Parides lycimenes. Papilionidae. Papilioninae.

Wedge-spotted Cattleheart, (Parides lycimenes)

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

A Gruesome End   2 comments


Philip Davison Nature Diaries. Bosque del Cabo Rain Forest Lodge.

Life as Normal

The weather pattern has now been set for the next three or four months.  The sun shines during the day and the rain comes down at night.  At least that has been the situation over the past week and if records from previous years tell us anything then that it how things should more or less remain until September.

Life continues here irrespective of the weather conditions.  One question I am asked a lot is “What do the animals do when it is raining?”  The animal life here is adapted to living in a rain forest so what happens is that everything continues as normal.

At the moment there are large groups of White-nosed Coatis, (Nasua narica), around the grounds.  The coatis are related to raccoons and like their cousins will feed on just about anything they find whether it be grubs and land crabs that they dig out of the ground, eggs and chicks stolen from birds’ nests or simply the abundance of fruit that has fallen to the ground.  The males are solitary and I found this one engrossed in a feeding frenzy with the jack fruits that were littering the ground beneath the tree that had produced them.  He was so preoccupied with the sweet treat that my presence was of no concern.

Nasua narica Carnivora Procyonidae

White-nosed Coati, (Nasua narica)

The females are gregarious and can be found in large groups which consist of the adult females and young of varying ages.  They are a little more wary than the males and if approached will run for the cover of dense vegetation.  This week some visitors to the lodge were greeted in the early morning by White-faced Monkeys, (Cebus capuchinus), in the tree over the cabin and a large group of White-nosed Coatis on the lawn in front.  All of a sudden the monkeys went berserk, barking a frantic alarm call.  The coatis bolted for the forest. That was a bad mistake as a few moments later a female Puma, (Puma concolor), emerged carrying one of the baby coatis in her mouth.  The guests experienced mixed emotions of being both sad and thrilled at the same time.

A few weeks ago I had a fledgling male Black-throated Trogon, (Trogon rufus), land beside me as I walked through the forest.  This time it was the turn of a female.  The females are not as vividly colored as the males.  The back is a soft brown and the belly is a pale yellow although it still has the eye ring and the black and white barred tail.

Trogon rufus. Trogonidae

Black-throated Trogon, (Trogon rufus) Female

Eaten Alive

Over many years of having lived in the area there are creatures that I have seen but have never been fortunate to take a photograph of.  It may well have been that I was not carrying the camera or that the sighting was too fleeting or that the subject would not stay in one spot long enough.  For whatever the reason the result was the same, a feeling of frustration.

One such insect that had evaded me for so long was one of the most predatory hymenopterans with a gruesome life history, the Tarantula Hawk.  These are impressively large wasps and one you most certainly not want to be stung by.  The female is the predator and she is constantly on the move in search of prey for her offspring, the living flesh of a spider.  As I am walking around, I have encountered over the years, individuals that land, with the antennae and wings in constant motion.  She alights and then takes flight almost immediately giving no chance of taking a photograph.  They are distinctive in size and tend to be bluey/black in color with bright orange wings.  This one also had orange antennae.

Pepsis aquila. Hymenoptera. Pompilidae. Pepsinae.

Tarantula Hawk, (Pepsis aquila)

This week I was lucky.  I found one resting at night, immobile and easy to trap, with the intention being of photographing her the next morning.  Once the sun rose I chose a suitable spot, set up the camera and tipped her onto the log in front of the lens.  I managed to snap a few images before she warmed up, cleaned herself, climbed up the tree trunk and took to the air.

Tarantula hawks belong to the family Pompilidae which has a large number of species many of which are spider hunters.  The genus Pepsis consists of about 300 species mainly distributed throughout Central and South America.  The adults are commonly seen taking nectar from flowers.

The large size of the Tarantula hawk enable it to hunt larger prey, as the name suggest, tarantulas.  It is thought that the females are particular about the species of tarantula that they hunt.  When a female finds a victim she will touch it with her antennae, the spider has a particular chemical odor that will identify it as the unfortunate chosen one.

Having made her selection the killer wasp grabs the tarantula by the leg and attempts to turn it over so she can inflict the paralyzing sting to the underbelly.  This is not without some danger to the wasp as its large prey can occasionally reverse the role and kill the killer.  Invariably though she delivers the coup de grace and the now immobilized spider can be dragged by the wasp to the spiders own burrow, there she lays a single egg, buries the victim and leaves it to its grisly fate.  While grappling in this life or death battle with the spider, the female wasp emits a pungent odor, the scent of imminent victory, whose real function is unknown.

As if being buried alive was not dismal enough, the egg hatches and because the spider is only paralyzed, not killed, the larva begins to consume the living flesh of the spider.  Eventually, once the feast is concluded, the larva spins a silken cocoon, pupates and sometime later a new assassin will emerge and repeat the process.

I see many smaller Pompilid wasps as I walk the trials.  I have watched them catch, sting and drag Wandering Spiders, (Cuppienius spp), to a burrow in a similar fashion.  Normally they are solitary but last week I noticed a group in a collective frenzy on the forest floor.  There seemed to be something at the center of the group that had captured their attention but I could not make out what it was.  The wasps were tumbling over each other to get at the object of interest but whatever it might have been will remain a mystery.

Pompilid sp. Hymenoptera. Pompilidae. Pepsinae.

Pompilid sp Searching for Something

One final wasp that I saw last week, or rather the nest of a wasp, was the unmistakable construction of a Mud-dauber Wasp belonging to the family Sphecidae.  These wasps are found globally but only six of the known species are native to the Neotropics.  What they may lack in species diversity they make up for in numbers, they are very common.

The tubes are made from mud that the wasp has collected from damp ground and fashioned into elongated cells.  These wasps, like the two species mentioned above are spider feeders.  These ones hunt smaller spiders which are dispatched in the same fashion.  Each of the mud cells is packed with paralyzed victims upon which an egg has been laid.  When the cell is full it is sealed and the spiders are left to suffer in immobilized silence.   These cells I noticed on the side of a tree but it is not uncommon to find them on the outer walls of buildings.

Sphecidae sp. Hymenoptera. Sphecidae.

Mud-dauber Wasp Nest – Cells of Lingering Death

Nameless Wonders

The fungi continue to produce their distinctive fruiting bodies.  Some of them are very eye-catching and some of them are compelling due to their strange appearance.  The stunning yellow mushrooms were found growing from the soil beneath the bamboos.  They were large but brittle, when touched they fell over.  Mushrooms appear overnight and only last a short time as they release the fungal spores into the air.  I found the second group of fruiting bodies growing from a dead branch on the forest floor.  They look like miniature branched corals reaching up and pointing to the heavens.  They were very small but the gregarious, monochrome white-tipped black stipes certainly attracted attention.

Agaricales sp. Osa Peninsula. Costa Rica.

Unidentified Mushroom

Xylaria sp. Xylariaceae.

Candle Snuff Fungus, (Xylaria sp)

Looking But Not Seeing

Harvestmen or Daddy Long Legs are strangely fascinating creatures.  They are, along with the spiders and scorpions, arachnids.  There are approximately 5,000 species of Harvestmen in the Order: Opiliones and most of them are found in the Neotropics.  Many people are familiar with these odd-looking creatures with the small globular body suspended between eight long filamentous legs.  The pedipalps at the front of the head are small and have weak claws at the tips.  They are commonly found on tree trunks where they hunt and feed on small arthropods such as mites and springtails.  They have the undeserved reputation of being one of the most venomous animals on the planet.  There is no factual basis for that claim but once one person says it and another repeats in then it becomes a fact with no standing in reality.

Opiliones

Daddy Long-legs with Legs Covered in Mosquitoes

They would appear to be very vulnerable to predation but they do have ways of avoiding becoming a meal.  They are generally nocturnal and cryptically colored so they blend in with the background.  If physically attacked then they can drop the leg that has been caught, (appendotomy).  The leg continues to twitch serving to hold the attacker’s attention.  They also have repugnatorial glands on the body from which they release a variety of foul smelling chemicals which repel a continuing attack.  If predatory ants are on the hunt, the harvestman lifts itself as high as the legs allow and then remains motionless.  The ants will only attack if they detect motion.

Having taken the photograph and then looked at it in detail I noticed something that I had not seen when I was looking at the animal on the tree, it’s legs were being covered by what appeared to be blood-sucking mosquitoes.  Searching online I could find very few records of mosquitoes feeding on the blood of other arthropods.  Obviously the harvestman has not developed a means by which to keep these specialist predators at bay but without further investigation it may well be that the mosquitoes were simply using the legs as a place to rest.

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

Unseen Wet and Dry Daggers   2 comments


Philip Davison Nature Diaries. Bosque del Cabo Rain Forest Lodge.

Dry Days, Wet Nights

The rainy season has arrived.  The initial rains were not too heavy but persistent.  Last week there was more or less constant rain all day, but light rain.  This week there have been sunny days with the rain falling at night.  For the past four days there has been only one rainy day and the night time skies have been clear and star filled.

The vegetation looks refreshed having been washed of a dry season’s worth of accumulated dust and dirt.  Verdant green is now the predominant color.  A lot of the trees are flowering and fruiting which is good news for those nectar or fruiting eating creatures.  Many of the non-native tropical ornamental plants found growing around the grounds have been planted for the beautiful floral and foliage displays they produce.  At the moment the Queen’s Crepe Myrtle, (Lagerstroemia speciosa), have the low growing crowns covered in deep lilac blooms.  That produces a sumptuous contrast to the deep green background of the forest.

Queen's Crepe Myrtle. Lythraceae. Osa Peninsula. Costa Rica.

Queen’s Crepe Myrtle, (Lagerstroemia speciosa)

The frogs have turned up at the breeding pond in reasonably large numbers.  Whereas in the dry season there are only one or two individuals of one or two species, we are now experiencing the presence of various species that have been noticeable by their absence over the past five months.  As it is only the beginning of the wet season, the intermittent dry days mixed with wet days cause nightly fluctuations in the numbers seen.  Given a few weeks then the amphibian breeding season will really take off and we will start to see large numbers of frog egg masses around the ponds.

Of course, when the number of frogs and frogs eggs increases so will the number of predators that prey upon them.  The number of Cat-eyed Snakes, (Leptodeira septentrionalis), seen around the pond at night has increased many fold.  Last week I found a small Terciopelo, (Bothrops asper), hunting small frogs in the vegetation at the pond edge.  It won’t be long before the large Terciopelos arrive to feed on the larger frogs, more particularly the giant Savage’s Thin-fingered Frog, (Leptodactylus savagei).

There were several Puma, (Puma concolor), and Ocelots, (Leopardis pardalis) caught walking past the trail cameras over the past week.  The cameras allow the lodge to monitor the presence of a great deal of wildlife, mammals more particularly, the roam the trails in the absence of people.

Colored Shelving

Frogs are not the only organism to have been stimulated into action.  The damp conditions have resulted in many fungi mycelia, which ramify throughout the soil and decaying vegetation, to produce fruiting bodies.  Most of them resemble the mushrooms and toadstools that we are familiar with at higher latitudes.  They commonly proliferate through the forests and fields with the oncome of autumn.  Here in the constantly damp conditions of a tropical rain forest you can find fungal fruiting bodies all year round, but at this time of year the sudden increase in humidity encourages a temporary reproductive burst.

Agaricales. Fungi. Costa Rica. Philip Davison

Unidentified Agaric Mushroom

Bosque del Cabo Rain Forest Lodge.

Weird and Wonderful Fungal Fruiting Bodies

In Europe and North America there is a great deal of readily available reference material to help identify mushrooms.  Here that is not the case.  But you don’t have to always put a name to something to enjoy the beauty of its color and form.  As they are relatively immobile they also make good photographic subjects.

Leucocoprinus sp

Leucocoprinus sp

Fungi are one of the vitally important constituents of the forest community and help the rain forest to function in the manner that it does.  The constant warm, damp conditions under the canopy provide an excellent incubator for fungal and bacterial action.  Although by no means are these the only two agents of decay and decomposition they are however two vitally important parts of that process.  Dead organic material rots very quickly, leaves as quickly as two weeks and fallen trees sometimes within two years.  The nutrients resulting from this rapid breakdown enter the soil but do not stay for long in the soil.  They are taken up by the vegetation almost as fast as they are produced.  Rain forest soils, apart from the top inch or so, do tend to be very nutrient poor, most the of the nutrients are above ground, locked up as part of the physical makeup of the plant life.

Fungus. Bosque del Cabo

Unidentified Fungal Fruiting Body

Many plants are rather poor at extracting nutrients from the soil.  To that affect the plant roots have a relationship with a fungal mycelium.  Quite often these relationships are specific, a certain plant species only having a relationship with its own species of fungus.  The fungal mycelium is very efficient at taking nutrients from the ground, a certain percentage of which are passed through the tree roots into the plant.  Fungi on the other hand are not photosynthetic and receive sugars produced by the plants in the reverse direction.

Sulfur shelf Fungus. Bosque del Cabo.

Sulfur Shelf Fungus, (Laetiporus sulphureus)

Not all fungi produce the familiar mushroom.  Take a close look and you will see a huge variety of other forms in the forest such as bracket fungi, cup fungi or cauliflower fungi.  They are all fascinating, not only in their life histories, but also in terms of their aesthetic qualities.

Bracket Fungus. Philip Davison.

Mysterious Bracket Fungus

Once Seen, Not Forgotten

There are some butterflies that I see throughout the year.  There are some butterflies that are seasonal.  Then there are those butterflies I only see occasionally.  Finally there are butterflies I have only ever seen once and then never again.  Many butterflies spend their adult days at the top of the canopy.  Forest edges are always a good location to find butterflies as are nectar plants in gardens.  Some butterflies are secretive and won’t venture out into the open, preferring dark secluded, undisturbed areas within the forest.

Last week I managed to find two of the occasionally seen butterflies on the same day and in the less visited areas of the forest.  Over the course of 17 years living in the area I have only found one or two individuals of these species.  I have not been able to take a decent photograph of either of them.  Last week that changed.

While walking along a forest trail, I noticed a small butterfly flitting back and forth from one plant to the next, always landing beneath the leaf, stopping for a few seconds and then taking flight once more.  I knew I had no chance of taking a photo if it continued in this manner.  I stayed still, camera ready in hand, and waited to see if it would rest for a longer period of time.  My patience was rewarded as it flew beneath a leaf in front of me and stopped.  I slowly lifted the camera to my eye and hoped that I would not disturb it.  My luck was in and it remained in position despite the flash firing so I finally managed to take a reasonable picture.

Callicore lyca. Biblidinae. Nymphalidae. Lepidoptera.

Aegina Numberwing, (Callicore lyca)

This butterfly is an Aegina Numberwing, (Callicore lyca).  The genus Callicore is restricted to Mexico, down through Central America and into South America.  They are generally found in the upper layers of the forest, typically in the subcanopy, and rarely venture down to ground level, only doing so to feed on rotten fruit.  I just happened to be in the right place at the right time to find this individual making a sortie to low levels.

Not so far along the trail a bright blue creature with a texture resembling velvet flashed past me.  By the time I noticed and looked to see what it might be, it had gone.  I continued walking and it seemed that this was to be a lucky day.  The creature, which I could now see as a butterfly, had crossed in front of me and flew over the top of low growing vegetation just a foot or so above the ground.  Once again it would not settle so I stood and watched its wandering path.  Unlike the last species, this one was briefly landing on top of the leaves.  Finally it stopped for a few moments not too far from where I was standing and I managed to capture the image.

Theorema eumenia. Theclinae. Lycaenidae. Lepidoptera.

Pale-tipped Cycadian, (Theorema eumenia)

The butterfly was a beautiful Pale-tipped Cycadian, (Theorema eumenia).  The cycadians belong in the family: Lycaenidae along with the hairstreaks.  They tend to be small butterflies and are quite often overlooked.  Had it not been for the sumptuous blue of the upper wing surfaces then I may have missed this individual.  When perched the wings are closed and the undersurface is black with pale v-shaped spots, shot through here and there with metallic blue.

One final butterfly that I managed to take a photograph of was one of the daggerwings.  This time I was out in the open in bright sunny conditions.  The gravel path was still damp from the previous night’s rain and in several spots there were rapidly drying puddles.  Many butterflies like to visit damp ground to engage in mudpuddling where they imbibe nutrient rich moisture.  That does not happen much in this area but one group of butterflies I do see indulging themselves in this way are the daggerwings of the genus Marpesia.

Marpesia alcibiades. Biblidinae. Nymphalidae. Lepidoptera.

Alcibiades Daggerwing, (Maresia alcibiades)

There are six species of Marpesia I find here, some more frequently than others.  The name reveals the distinctive feature, the tip of the hindwing has a long drawn out dagger-like extension.  Daggerwings are found in North, Central and South America as well as the Caribbean Islands.  This species is Marpesia alcibiades.  It is rarely recorded in the wild but that may be due to the fact that it is easily mistaken for several other similar looking species.  Here I found myself faced with a choice of five individuals at my feet.  I ended up on my belly lying prone on the ground to get the shot.  That fills another blank space in the collection.

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

Mysteries of the Natural World   Leave a comment


Philip Davison Nature Diaries. Bosque del Cabo Rain Forest Lodge.

Frog Chorus

The week has been dry and sunny but with the clouds progressively becoming a more frequent feature.  Increasingly the skies are becoming overcast and the azure blue of the dry season has been replaced by a blanket of grey.  The sun manages to peep through for a while but then is lost once more behind an obscuring haze, only the faint outline of its orange disc visible to the naked eye.

The amphibian population is gathered and ready for the real rains to begin.  There are more male frogs setting up territories at each location around the pond.  The Savage’s Thin-fingered frog and the Marine Toads prefer the pond edge.  The Banana Frogs and the Small-headed Frogs situate themselves on the vegetation floating on the water.  A little higher up the Milky Frogs have taken up their positions on the upper surfaces of the leaves overhanging the water.  Finally the Red-eyed Green Tree Frogs can be heard calling from nearer the tops of the vegetation.  When the rains do arrive, with the typical early May deluges, the activity around the pond will increase exponentially.  More species will arrive, particularly the ones that reproduce directly in the water.  It is just a matter of time.

Red-eyed Green Tree Frog. Hylidae. Phyllomedusinae.

Red-eyed Green Tree Frog, (Agalychnis callidryas). Male. Calling.

Skipping Over Marked Metal

Butterflies exhibit a variety of dimorphisms.  They may be sexually dimorphic, strongly or otherwise, males and females may look like completely different species. They maybe seasonally dimorphic, wet season forms differing from dry season forms.  They may be geographically polymorphic with one species varying in size, color and markings over a wide geographical range to the point where you would once again think you were looking at totally different species.

One of the more commonly seen riodinids, or metalmark butterflies, in the forests of Bosque del Cabo is Metacharis victrix.  I regularly see the fiery orange females but not so often the males which are much more of a deep brick red.  They have the frustrating habit of perching on the underside of leaves so to capture the image you have to get on the ground, lie on your back and point the camera upwards.

Metacharis victrix. Riodinidae. Riodininae

Metacharis victrix. Male.

They are frequently found in bright understory light gaps.  The larval food plant is any one of the Heisteria species of which, Heisteria accuminata, is very abundant in this area.

Heisteria accuminata. Olacacea

Heisteria accuminata. Fruit

The skippers are a difficult family of butterflies to identify too.  A great many of them are very small, sometimes no bigger than an adult human fingernail.  To add to the problem of identity, there are so many of them and they quite often they are muted shades of brown.  It does take a certain level of expertise to identify them to species level.

Last week I had one land close to me and fortunately stay still.  Skippers are prone to taking flight at the slightest disturbance and are also averse to the camera flash going off.  This individual was the Perching Saliana (Saliana esperi).  The earthy brown of the hindwing underside has a contrasting creamy flash.  There are two pale windows in the dark half of the wing.

Perching Saliana. Hesperiidae. Hesperiinae.

Perching Saliana, (Saliana esperi)

It’s a Mystery

As much as I would love to study moths as well as butterflies, time does not allow this luxury.   There are up 14,000 species of butterfly and moth in Costa Rica, the majority being moths.  Many of the moths we have no idea of their life histories.  So when a moth does turn up that I can take a photograph of, if I cannot arrive at an identity then I do not fret over the fact, I just enjoy it for what it is, a beautiful thing to behold.

Unidentified Moth. Philip Davison.

Unidentified Moth

Actually that holds true for many insects.  Costa Rica has an estimated 365,000 named species of insects within its territory, that is 1,000 species for every day of the year, which would require exceptional identification skills.  Identity to species level is best left in the hands of those who specialize in a particular group.  I found a stinkbug sitting on a leaf that made a wonderful subject but I have not been able to name it to species level.

Stinkbug. Hemiptera. Heteroptera.

Unidentified Stinkbug

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

Sisters Singing to Ruffled Youth   Leave a comment


Philip Davison Nature Diaries. Bosque del Cabo Rain Forest Lodge.

Frog Chorus

Once again there have been several nights of rain over the past week.  It won’t be long before the rains become the norm and we move into seven months of the wet season.  The frogs have responded by turning up en masse.  The initial explosive Milky Frog, (Trachycephala venulosa), breeding period will reach an early peak and then they will disappear for the next eleven months, hidden out of sight deep in the vegetation and tree tops.  Throughout the dry season there have been the persistent calls of one or two Banana Frogs, (Dendropsophus ebreccatus).  The calls were in vain as no females were present to respond to them.  Now, however, over the past week many more males have turned up, each one setting up its territory on a seperate Water Hyacinth leaf.  The females have also turned up so the leaves should be covered in egg masses before too long.  Up in the tree tops the forlorn calls of one or two Red-eyed Green Tree Frogs, (Agalychnis callydryas), has turned into a chorus and I have already witnessed several egg laying episodes.  Another frog that has not been heard throughout the dry season turned up at the pond, the Small-headed Frog, (Dendropsophus microcephala).  At first glance it looks like a Banana Frog but it has a yellow line that runs down its sides and lacks the small bright yellow patch beneath the eye on the top jaw that is so distinctive of the Banana lookalike.

Small-headed Frog. Hylidae. Hylinae. Osa Peninsula. Costa Rica.

Small-headed Frog, (Dendropsophus microcephalus). Male.

Finding Rare Sisters

As the amphibian numbers increase, so do the butterfly numbers decrease.  There are still plenty around both in terms of individuals and species but over the next few months these will disappear and dwindle to only occasional sightings.  One butterfly I managed to get a photograph of this week was the Boeotia Sister, (Adelpha boeotia).

Boeotia Sister. Philip Davison.

Boeotia Sister, (Adelpha boeotia)

The genus: Adelpha, commonly known as the “Sisters”, is a notoriously difficult group to identify to species level.  The features distinguishing each species need to be seen in detail and that is generally only possible if they are at rest and that never seemingly is the case, they are very active, always on the wing.  Of course some are more distinct than others and when you are familiar with the species in your area that helps too.  A common feature of the genus is the white band traversing the dorsal surface of the wings which may extend over both wings or be replaced to a greater or lesser extent on the forewing by orange.  There are thirty species in Costa Rica and they are found in almost all terrestrial habitats.  They never occur in large numbers.  The adults feed on rotting fruit and I was lucky enough to find this individual on the ground feeding from fallen fermenting figs.

Disheveled Youth

On my day out walking the butterfly transect, as I returned across the bridge a juvenile Black-throated Trogon, (Trogon rufus), landed right beside my head.  The bridge traverses a ravine running through the canopy.  At this point you are essentially at the top of the trees.  The trogon looked just newly fledged.  Unfortunately I had a macro lens attached to the front of the camera which was set to photograph butterflies at close range.  I couldn’t miss the opportunity being presented though and with no time to change anything I just lifted the camera and pressed the shutter button.  As the flash went off, the young bird took to the air and disappeared.  But I did at least get one photo.

Black-throated Trogon. Felipe del Bosque. Bosque del Cabo.

Black-throated Trogon, (Trogon rufus). Juvenile

The trogons are fairly sedentary birds.  The male and female can normally be found very close to one another so if you find one then the other will not be too far away.  The plumage can be quite spectacular with the males being brighter than the softer colored females.  The Black-throated Trogon male has a bright metallic green head, back and upper chest.  The belly is bright yellow and of course it has the black throat after which it is named.  The bill is bright yellow and it has a blue eye ring.  The call is a soft trilling sound.  They feed on small fruits and insects.

Flower to Fruit

Some of the fruit trees around the grounds have been coming into flower over the last week.  Guavas, (Psidium gaujava), are native to Costa Rica but are cultivated all over the world.  They flower and fruit several times over the course of the year.  The white flowers are found singly and have a faint perfume.  Later the fruits appear.  They are green with a sweet pink flesh inside which contains the seeds.

Guava. Bosque del Cabo.

Guava, (Psidium guajava) Flower

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

Posted April 24, 2017 by felipedelbosque in Uncategorized