A Passion for Ant Killing Lions   4 comments


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

No change in the weather this week.  We have had another seven days of hot, sunny weather.  There were two days when the clouds had formed and the sky remained overcast but no rain resulted although the temperatures plummeted from 104⁰F to 96⁰F.

The butterfly numbers are increasing but still way below what would be expected for this time of year which is normally the peak of butterfly activity.  Around the pond at night, the Savage’s Thin-fingered Frogs are starting to gather in greater numbers.  The pond is the last remaining damp area on site.  The flowering period for many of the trees has finished and now some of them have started fruiting.

The major excitement this week has been the presence of a female Puma, (Puma concolor).  She had been seen in several different locations around the grounds.  The high-pitched barking alarm call of the Spider Monkeys is always an indication of where the cat is passing by.  One day, as the sun was setting, the alarm calls of agitated monkeys and agoutis started the fill the air.  The cat was on the prowl.

She left the cover of the forest and walked through an open garden.  That is where I spotted her.  She was in no hurry and it was patently obvious that she could see me.  She crossed the driveway and made her way into some dense vegetation.  The monkeys settling down in that area for the evening were suddenly stirred into action and more alarm calls began to build eventually reaching a fever pitch.

She emerged from the tangle of dense vegetation and slowly walked toward the edge of the cliff overlooking the ocean.  An Agouti that was in the same vicinity saw the cat, let out a loud shriek and ran off with its hair stood on end.  The cat immediately looked alert but then just as quickly lost interest.  She sat down and started to clean herself before lying down for a few minutes.  She then rose to her feet, turned her back on me and walked off into the rapidly darkening forest.

There was another predator that I managed to get very close to this week.  Very close.  While I was out conducting my butterfly counts I found a juvenile Broad-winged Hawk, (Buteo platypterus), sitting on a low cut tree stump on a trail through an open area of forest.  It was an ideal opportunity to take a photo.  I fully expected the bird to take off and fly away but it remained where it was and just looked at me.  I approached closer and closer but very slowly, each time taking a photo.  Eventually I ended up lying on the ground within touching distance but the bird never even flinched.  I kept a wary eye to my surroundings as it was not beyond the possibility that the parent birds would be keeping watch and attack should I get too close but nothing happened.

Broad-winged Hawk. Accipitridae. Philip Davison.

Juvenile Broad-winged Hawk, (Buteo platypterus)

Broad-winged Hawks are migratory throughout North, Central and South America.  They tend to hunt in the understory of the forest from where they swoop down and take small rodents and lizards from the ground.  The broad wings and short tail are a good visual identification feature.

Buteo platypterus

Close up of Juvenile Broad-winged Hawk, (Buteo platypterus)

A New Passion For Flags

Along the forest trails there are several species of Passion Vine currently in flower but this week I found one species that I had never seen before.  I returned with the camera and took photos for the record and to identify this new species.  –

There are sixteen species of Passion Vine to be found in the forests of the Osa Peninsula.  One is seen throughout the year at Bosque del Cabo Rain Forest Lodge, the Scarlet Passion Vine, (Passiflora vitifolia).  It is hard to miss the bright red flowers suspended on thin, fleshy, green stems that grow up from the ground and entwine the vegetation.  Two others flower only occasionally.

The new species, Passiflora pittieri, is normally found in primary forest but at the top of the canopy or in light gaps.  The flower is very distinctive with its pale cream petals and a corona of yellow-tipped orange filaments and pink-flushed anthers.  This one appears to be insect pollinated as I could see bees visiting the blooms.

Passifloraceae. Bosque del Cabo.

Passiflora pittieri

The leaves of this species are highly cyanogenic.  When physically damaged they release cyanide which would normally deter most creatures from eating them.  But where there is a system then there is a way round the system.  There are many species of longwing butterfly the larvae of which feed on the leaves of various species of passion vine.  The larvae have an enzyme that allow them to sequester the cyanide molecule and use it in turn as a toxic defense.  The caterpillars can only eat the young leaves as the older leaves will have become too unpalatable.

Cydno Longwing. Nymphalidae.

Cydno Longwing, (Heliconius cydno)

Heliconius sapho. Heliconiinae

Sapho Longwing, (Heliconius sapho)

Another insect associated with passion flowers are the flag-legged bugs.  These phytophagous, or leaf-eating, members of the Order: Hemiptera, Su

border: Heteroptera and Family: Coreidae can usually be found clustered around the flowers of passion vine.  Their rearmost legs have a large expanded flat and colored section.

Flag-legged Bug. Hemiptera. Heteroptera.

Flag-legged Bug, (Anisoscelis flavolineata)

Flag-legged Bug. Philip Davison. Bosque del Cabo

Flag-legged Bug, (Coreidae sp)

If a predator approaches a Flag-legged Bug, then the insect will wave one of its two brightly colored expanded rear legs.  This provides a target for the attacker which will end up with little more than a leg for its efforts while the bug will have flown away.  Many Flag-legged Bugs will be observed with either one or both rear legs missing.

The Pit of no Escape

This time of year with the ground having become very dry and friable, there are many small crater-like pits that have appeared all over the trails.  It would appear as if a miniature meteor storm had hit the area.  Further investigation, more particularly by disturbing the sides of the crater wall, will result in small grains of sand erupting upwards towards the source of the disturbance.  Buried and hidden at the bottom of the pit is a larva of an insect closely related to Lacewings and Owlflies, the Antlion, and it is this larva which is responsible for throwing the sand grains.

Myrmelon sp. Neuroptera.

Antlion, (Myrmelon sp), Pit

The Antlions belong to the Family: Myrmeleotidae within the Order: Neuroptera.  Only antlions of the Genus: Myrmelon create the pits.  The larva excavates the steep-sided pit and places itself at the bottom, just beneath the surface and covers itself with the fine sand.  They don’t just feed on ants, any small insect venturing within the crater rim will find itself struggling to leave.  The more it struggles to climb out, the more loose material it will dislodge causing it to slip towards the bottom.  The predatory larva lying in wait will now begin its performance of death to bring down the final curtain on the life of its victim.

Myrmelon sp

Mandibles of Antlion, (Myrmelon sp), Larva Grabbing Hapless Ant

Using the front legs the larval antlion flicks sand up at the ant desperately trying to escape the steep sided crater.  This serves to drag it further down towards the bottom of the pit.  When it finally slips all the way down, then the mandibles of the larva snap shut around the prey’s body.  This is what I was observing.  The unfortunate ant was struggling to escape the deadly grip of the mandibles but to no avail.  Sharp projections on the inside of the mandibles pierce the ants body and the larva sucks the juice out of the ant.  Once it has finished the remaining dry and drained carcass is flicked out of the pit while the larva awaits a fresh potential food item to enter.

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

Grumpy and Toxic if Touched   Leave a comment


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

Last week continued to be hot and sunny.  There was not a drop of rain.  The trails through the forest are now becoming heavily cracked.  The lawns around the lodge are definitely more brown than green.  The forest however remains vibrant, there is no sign of drought stress.  The huge volume of water that fell as rain last November has ensured that the creek is still running quite well, more so than would be expected for this time of year.  The dry season is typically when a lot of leaf fall occurs.  That is the case at the moment.  The trails are cleared and a few days later there is a layer dry, brittle brown leaf covering the path once more.  Some of the trees that have been in bloom over recent weeks are coming to the end of the flowering period.

Felipe del Bosque. Philip Davison.

The Forest Floor is Rapidly Drying and Cracking Up.

Brushing Toxic Hair

Although I spend my days monitoring butterfly populations and see plenty of the adults flying around, it is only very occasionally that I see the larvae or caterpillars.  It may well be that because I am not actively searching for them that I am not seeing them.  There are over 7,000 named species of butterfly in the Neotropics and that number is dwarfed by the number of moth species.  Many butterflies and even more moths have unknown life histories.  Quite often we don’t know what the larval form looks like or what host plant they feed on.

Unidentified Moth Caterpillar.

Unidentified Moth Caterpillar

Caterpillars are the feeding and growing period of the butterfly or moth life cycle.  Feed and grow they do and at an amazing rate.  Caterpillars are quite often restricted to feeding on a single species of plant, sometimes on a few species within one genus or sometimes several species in the same family.  Each species does not have a large variety of choices.  After hatching from the egg, the caterpillar can increase in size by over a hundred times before it pupates.

Being a large, constantly and rapidly growing creature, the caterpillar has to remain unseen by predators or if seen, then has to have a secondary range of defenses such as irritating spines or hairs or to feed on plants poisonous to other creatures, store the toxins within its own tissues and warn off potential predators with bright warning, (aposomatic), coloration.

Over recent weeks I have stumbled across several caterpillars as I was out walking around the forests of the Osa Peninsula.  I was not looking for them, they just happened to catch my eye.  Any caterpillar sporting a battery of spines or hairs is one that you should avoid handling.  The spines and hairs may exude toxin secretions that can cause intense irritation.

Saddleback Moth Caterpillar. Osa Peninsula. Costa Rica.

Saddleback Moth, (Acharia hyperoche), Caterpillar.

The caterpillar of the Saddleback Moth, (Acharia hyperoche), usually hides on the underside of the palm leaves on which it is feeding.  It has green coloration that helps it blend in with its background.  The saddle marking may help to break up its outline.  If the ruse does not work and it is spotted by a keen-eyed predator, then it has a second line of defense.  The body anterior, posterior, laterally and dorsally has fleshy protuberances that carry batteries of sharp urticating spines.  The slightest brush against this living, toxic slug-like creature will result in a red itchy rash and a certain degree of pain.  Many other species of moth in the same family, Limacodidae, are protected in the same fashion.

Limacodidae. Philip Davison. Bosque del Cabo Rainforest Lodge.

Unidentified Limacodidae species.

Another group of species which belong to the Silkmoth family, Saturniidae, more particularly of the subfamily, Hemileucinae and the genus Automeris also have caterpillars which protect themselves in a similar fashion.  The body is green and quite literally covered in urticating bristles.  The adult Automeris moths are very distinctive too.  The dorsal surface of the forewings are colored and patterned to resemble dead leaves.  Should anything disturb these particular leaves though they are in for a shock.  The forewings swing forward which reveals two large eye-spots on the dorsal surface of the hindwings.  As far as the predator is concerned it could well be looking at a much larger predator staring back at it from the ground.

Automeris sp.

Automeris sp. Caterpillar

Saturniidae. Hemileucinae.

Automeris sp. Adult.

Sometimes it may prove prudent to let a potential predator know that you are likely to cause them harm when touched.  Some of the Dagger Moths, (Acronicta spp), caterpillars are covered in long lemon yellow hairs with contrasting black tufts.  If touched these hairs can break and become embedded in the skin.  The longer black hairs are attached to a gland than secretes a toxin that will leave a nasty little rash on human skin.

Acronicta sp.

Dagger Moth sp. Caterpillar.

As well as the finding  of caterpillars is difficult, then locating the chrysalis’s is equally, if not more, challenging.  Admittedly I don’t go looking for them and so if I do discover one then it is entirely by chance.  The one species that I find more than others is the Narrow-banded Owl-butterfly, (Opsiphanes tamarindi).  That may be due to the fact that the larvae feed on Heliconia, Maranta and Bananas of which there are many plants around the bar and restaurant areas of Bosque del Cabo.  A chrysalis has little by way to defend itself and so crypsis might be the best option.  Green coloration is a good way of camouflaging yourself against a background of green vegetation.  This one I noticed hanging from the underside of a leaf beside the bar.

Narrow-banded Owl-butterfly. Nymphalidae. Morphinae.

Narrow-banded Owl-butterfly, (Opsiphanes tamarindi). Chrysalis.

Grumpy Big Head

There are six species of Anolis lizards living on the Osa Peninsula.  On the grounds of Bosque del Cabo Rainforest lodge I have encountered five of those species and the remaining one as an ,isolated population several miles away.

When I was out walking the Titi Trail this week I saw a the Big-headed Anole, (Anolis capito), lying languidly on the root of a large fig tree.  As I slowly approached with the camera in hand, it opened one of its eyes and looked at me with a doleful expression as if to say don’t even think of bothering me.  But I did take some photographs and each time the flash went off the lizard moved, almost imperceptibly, further around the root in a direction away from me.

Big-headed Anole. Polychrotinae. Igunaidae.

Big-headed Anole, (Anolis capito).

The Big-headed Anole is one of the larger anolis lizards in this area.  It attains a length of 9 inches including the tail.  It’s body color is a mottling of greens, greys and browns.  It can be found on the trunks of trees where it normally perches head down waiting for food items, arthropods or small lizards, to pass by.

Slender Anole.

Slender Anole, (Anolis limifrons).

Two of the more commonly seen anolis lizards are the Slender Anole, (Anolis limifrons), and the Golfo Dulce Anole, (Anolis osae).  Both of these species can be commonly found around human habitation.  The Slender Anole as the name suggests is a small slim species, mottled brown in color and with a white underbelly.  The Golfo Dulce Anolis is slightly more robust and uniform brown in color, (at least the males), with a distinctive white stripe along the body behind the shoulder.  Both of these species live close to the ground, again facing head down but usually at the end of large leaves.

Golfo Dulce Anolis. Polychrotinae. Iguanidae.

Golfo Dulce Anole, (Anolis osae)

Green Canopy Anole. Osa Peninsula. Costa Rica.

Green Canopy Anole, (Anolis biporcatus)

The last two species in this immediate area is the Green Canopy Anole, (Anolis biporcatus), and the Lichen Anole, (Anolis pentaprion).  They both tend to live higher up in the canopy.  I see the Canopy Anole more often at night where I find it lying asleep on the tops of leaves.  It’s bright lime green coloration stands out quite nicely in the beam of a flashlight.  The Lichen Anole I have found at the top of the canopy.  It is grey in color with pale spots.  Both of these two anoles I only find very occasionally whereas the other three can be found without much effort.

Lichen Anole. Polychrotinae. Iguanidae.

Lichen Anole, (Anolis pentaprion)

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

 

 

Mornings Glorious Dragons and Damsels   4 comments


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

The transition from the wet into the dry season is normally marked by a variety of changes that are both easy to see and hear.  So far those changes have not been that obvious for 2017.  The unusually heavy rains during November and December last year would appear to have delayed, if not completely altered a lot of plant and animal behaviors.  But now, some two months after expecting to see certain changes, they are beginning to take place.

There has been a late start to the flowering season for many trees.  This week some of the trees that would have been expected to flower in December are now flowering in February.  One notable example is the Ajo Tree, (Caryocar costarincensis).  Its bright lemon yellow blooms can now be seen littering the forest floor on many of the trails.  Take a trip up into the tree tops on the canopy platform and you will find many species of tree crowns covered in flowers.  This is turn attracts many butterflies and they can be seen flying from flower to flower, tree to tree, all around the sunlit forest canopy.

Caryocar costaricensis. Caryocaraceae.

Ajo Tree, (Caryocar costaricensis). Flowers.

Rain forests in general can be windless areas.  The forests of the Osa Peninsula experience very little wind except when a heavy rain approaches pushing a pocket of air in front of it.  The plants therefore have to rely for the most part on animals to carry out both pollination and seed dispersal. Bats are very important pollinators and seed dispersers.  Bats prefer musky odors to sweet odors.  This results in the plants emitting various scents that humans would not be expecting, being used to the more fragrant sweet smell of flowers.  The bats however are attracted by the scent of garlic.  The nectar feeding bats have a long muzzle and a long sticky tongue.  While they are feeding on the nectar, the long anthers of the flower dust pollen over the head and shoulders of the bat which then flies off to visit another flower transferring the pollen and effecting pollination.

In subtle contrast to the green of the hedgerow vegetation are the strong purples of the Morning Glory, (Ipomea) which are currently flowering.  This is a vine which wends its way through the hedges.  The purple color is attractive to insects.  The flowers prefer the full sun despite the name “Morning Glory” which refers to the flowers unfurling at first light of dawn.

Ipomoea sp. Convolvulaceae.

Morning Glory, (Ipomoea sp)

The butterflies are starting to be seen in greater numbers but the levels fall a long way short of what would be expected at this time of year.  The height of the butterfly season is between February and March but so far the visible populations, particularly of some species, are noticeably down.

Metacharis victrix. Riodinidae

Metacharis victrix

At night the number of amphibians is starting to diminish.  For some time now the number of species has reduced to 4 or 5 but the number of individuals of each species has dwindled to only one or two hopeful males calling for a mate.  It is highly unlikely that there will be a response at this time of year.  The Savage’s Thin-fingered Frogs, (Leptodactylus savagei), are increasing slightly in numbers around the pond.  As the area continues to dry the pond is the only damp refuge and these large amphibians start to congregate around the pond edge sometimes entering the water where they can be found floating.

Floral Descent

Whereas many of the plants have been slow to flower, some of the orchids have not..  To see the orchids you generally need to up in the forest canopy, 88% of the Costa Rican orchids are epiphytic, they are up at the top of the trees.  But occasionally you may be lucky to see some that have found a suitable location nearer to the ground.  When not in bloom it is easy to miss them as many orchids have small insignificant flowers,  but  not all, others when in flower can have quite a showy display.  Orchidaceae is a very species rich family of flowering plants rivalled only by the Asteraceae or daisy family in terms of numbers.  Being so diverse makes them hard to identify.  Many people admire them for their aesthetic, if sometimes subtle, beauty.  They are therefore a group of greater interest to orchid specialists in terms of identification and geographical distribution.  Equaled by the diversity of species and form of the flowers are the number of ways in which orchids become pollinated.  Some of them have evolved means of attracting pollinators that would seem to be, on first reading, the stuff purely of science fiction.

Around the gardens and forests there are orchids that are slightly more obvious.  Growing on some of the garden trees as epiphytes are the white-flowered, night-perfumed Lady of the Night, (Brassavola nodosa).  At night the white flowers give off a heavy sweet perfume that attracts in hawkmoths.  The moths hover in front of the flower and using the long proboscis probe for nectar.  While doing so they become covered in pollen which is then transferred to the next flower they visit.  Not too far away growing in the borders are the Bamboo Orchids, (Arundina graminifolia).  This is a terrestrial orchid native to south east Asia.  It is however widely grown in Costa Rican gardens.  The purple bee pollinated blooms are born on long thin stems that resemble a bamboo stem.

Brassavola nodosa. Orchidaceae

Lady of the Night, (Brassavola nodosa)

On the forest trails growing low down and in locations near to water you may find, (Stanhopea cirrhata).  Stanhopea species emit an scent that attracts certain species of orchid bee.  The males gather the scent which they mix with other plant volatiles to produce their own perfumes.  The structure of the Stanhopea orchid is such that while the bee is gathering the scent a pollen package is attached to the bee which unwittingly transfers it to the next orchid it visits.

Stanhopea cirrhata. Orchidaceae.

Stanhopea cirrhata

There are some orchids whose flowers are as green as their leaves. Numbering amongst them is the Vanilla Orchid, (Vanilla planifolia).  In the wild Vanilla orchids are pollinated by orchid bees but when commercially grown and pollinated by hand.  Growing on the sides of trees are some of the green flowered Epidendrum Orchids.  There are about 160 species of Epidendrum in Costa Rica which makes them a little difficult to identify.

Vanilla planifolia. Orchidaceae.

Vanilla Orchid, (Vanilla planifolia)

Epidendrum sp. Orchidaceae.

Epidendrum sp

Dragons and Damsels

If you spend enough time by any body of water around the grounds then you are likely to see some of the Odonates; dragonflies and damselflies.  The dragonflies can more commonly be found still bodies of water such as the pond whereas the damselflies seem to frequent areas closer to running water such as the creek.  They can also be seen in the gardens and throughout the forest too.  You can tell a dragon from a damsel when they land as the dragonflies perch with the wings out to the sides whereas the damselflies perch with the wings folded together over the back.

You have to have patience to photograph dragon and damselflies.  They react to the slightest movement near them by taking to the air.  They do have favored perches though so if you set the camera up on a tripod or simply rest in a comfortable position, camera in hand, they well almost always return in short time and alight at the place from which they took off.

Erythemis versiculosa. Libellulidae. Odonata.

Great Pondhawk, (Erythemis vesiculosa)

Erythrodiplax fervida. Libellulidae. Odonata.

Red-mantled Dragonlet, (Erythrodiplax fervida)

Micrathyria didyma. Libellulidae. Odonata.

Three-striped Dasher, (Micrathyria didyma)

Megaloprepus caerulatus. Pseudostigmatidae. Odonata.

Helicopter Damselfly, (Megaloprepus caerulatus)

Mecisogaster ornata. Pseudostigmatidae. Odonata.

Ornate Helicopter Damselfly, (Mecisogaster ornata)

Hetaerina orissa

Hetaerina orissa

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

A Brush With Passionate Bats   4 comments


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

As the dry season progresses and the temperatures continue to soar then the ground begins to dry and crack.  Nearly two months into the dry season and the grass has lost its green appearance turning a pale brown.  A layer of dirt is building up on the leaves of the plants, particularly on the roadside verges where cars have thrown up a dust storm with every passing, giving the vegetation a dull, tired look.  The cicadas have started to call during the day but not with the intensity you would expect at this time of year.  As the sun starts to sink low on the horizon the cicadas go silent, momentarily, until the sundown cicadas pick up the volume once more.  The butterflies are increasing in numbers but way below the levels normally associated with nine weeks into the dry season.  I have been fortunate enough to see one new species that I have never encountered before, a tiny little Alcandra Skipper, (Gorgothion alcandra), that I would probably not have noticed if it had not been for my looking at two other larger butterflies in the same location.

Gorgothion alcandra. Hesperiidae. Pyrginae

Alcandra Skipper, (Gorgothion alcandra)

Eurema daira. Pieridae. Coliadinae.

Barred Yellow, (Eurema daira)

Whitened Eyed-metalmark. Riodinidae. Riodininae

Whitened Eyed-metalmark, (Mesosemia zonalis)

Brushes for the Bats

Most of the trees that would normally be expected to have started blooming are devoid of flowers.  However, there are exceptions.  The Pochote tree, (Pachira quinata), which is not native to the tropical wet forests of south west Costa Rica but rather the dry forests of the north west, is currently producing a huge number of creamy colored flowers that resemble shaving brushes.  During the course of one night it can produce many flowers which are pollinated by bats and hawkmoths.  Next day the spent blooms all fall and litter the ground beneath the tree.  Another tree in the same family, Malvaceae, is also flowering at the moment, the Barrigon, (Pseudobombax septenatum).  Like the Pochote the flowers are creamy white but the anthers are more numerous and dense.  They are, once more, bat pollinated.

Pachira quinata. Malvaceae.

Pochote Flower, (Pachira quinata)

Pseudobombax septenatum. Malvaceae.

Barrigon Flower, (Pseudobombax septenatum)

Passion for Sky Blue

Some of the vines are now flowering.  The Sky Vine, (Thunbergia grandiflora), as well as two species of passion vine, the Perfumed Passionflower, (Passiflora vitifolia), and the Giant Grenadilla, (Passiflora quadrangularis), have both produced a colorful display of blooms this week.  The Sky Vine winds its way through the tree tops and is largely goes unnoticed until it flowers.  Then the large blueish purple trumpet shaped flowers can be seen decorating the canopy in contrast to the green of the leaves.  Sky Vine originates from India but has been long cultivated in Costa Rican gardens from where it escaped into the wild.  The flowers are pollinated by bees during the day and by bats at night.

Thunbergia grandiflora. Acanthaceae.

Sky Vine Flowers, (Thunbergia grandiflora)

Both of the passion vines are more obvious at a lower level.  There are over 400 species of Passion Vine but the flowers are all more or less similar in form and function.  In the centre of the flower is a nectar producing disc.  A corona of stiff hair-like structures surrounds this.  These protect the nectar supply from non-pollinating creatures  The Perfumed Passion Vine has scarlet red flowers which attract pollinators, in this case hummingbirds.  The Giant Grenadilla has very showy purple flowers which are pollinated by large bees.

Passiflora vitifolia. Passifloraceae.

Perfumed Passion Vine Flower, (Passiflora vitifolia)

Passiflora quadrangularis. Philip Davison. Felipe del Bosque.

Grand Grenadilla Flower, (Passiflora quadrangularis)

Why Passion Vine is the common question.  The deeply religious early Spanish settlers could see within the structure of the flowers a symbolic representation of the Passion of Christ.  The three styles being the nails, the five anthers being Christs wounds, the corona is the crown of thorns, the tendrils –  the whips, the pointed leaves – the Holy Lance and the ten petals are the ten faithful apostles.

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

Jumping in Dutch Red Dirt   2 comments


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

The days are now consistently sunny, hot and dry.  Changes are happening in the observable flora and fauna.  Butterfly numbers are increasing in terms of both the number of species and the number of individuals.  But the numbers are still very much lower than would be expected for this time of year.  It could well be that the extended and intense rains of November resulted in the death of many larvae and pupae.  It may take time for those numbers to recover, especially considering the continuing decline seen over the recent two decades.

This time of year is usually noteworthy for the trees and other rain forest plants coming into flower.  There is some visual evidence of several trees coming into bloom but once again not in the number or variety associated with the onset of the dry season.

One other creature notable by its absence at the moment are the cicadas.  January is regarded as the start of a three month period when, during the day at least, your eyes are subject to a continual sonic bombardment of an indescribable intensity.  The larval stage of the cicada is spent below the ground where they feed on sap from plant roots.  It is not beyond the bounds of possibility that many of the larvae were drowned thereby reducing the number of emerging adults which are generally to found in millions this time of year.  For many people that aural attack will not be missed but the ramifications on the ecosystem may have long lasting effects.

Red Alert

One feature of the transition from the wet into the dry season that is very evident as you walk through the forest at this time of year is the production of new leaf.  The feature that makes the new leaf so obvious is the color – red.  Cabo Matapalo is on the South West tip of the Osa Peninsula, Costa Rica.  The location is only 8⁰ North of the Equator.  Any sunlight hitting the earth’s surface at this latitude is therefore intense sunlight and significantly high in ultra violet radiation.  Ultra violet radiation damages developing tissue.  The plants produce a red pigment called anthocyanin which is deposited over the developing chloroplasts and protects them from irradiation.

Anthocyanin

Red is the Color of New Leaf in the Rain Forest

As the chloroplasts mature the plant reabsorbs the anthocyanin and now lays it down as a layer on the bottom of the leaf surface.  Light hitting the forest floor is only 1% of that hitting the canopy so light is of a premium.  Light hitting the leaf will pass through and be bounced off the underlying red layer and reflected back up through the leaf surface so that any light required by the plant to carry out photosynthesis it missed on the way down it will pick up on the way back through.

Many of the young leaves hang droopily facing down.  Those that have no anthocyanin and not having developed much chlorophyll, look pale and ghostly in the in the gloom beneath the canopy.  At this point they are flaccid and not until water is absorbed by the cells do they become turgid and assume their horizontal light gathering aspect.

Fatima Fiesta

One of the butterflies that exhibits very profound seasonal fluctuations is the White Banded Fatima, (Anartia fatima).  It is one of the commonest Costa Rica butterflies.  It is hard to miss with the white bands on the wings contrasting starkly with the dark brown ground color as it flies in open sunny areas such as gardens and disturbed ground.  It can be seen visiting a wide variety of nectar plants.

Whtie-banded Fatima. Nymphalidae. Nymphalinae

White-banded Fatima, (Anartia fatima)

White-banded Fatimas can be found throughout the year in greater or lesser numbers.  This week the numbers started to increase very rapidly.  In some locations there were dozens of them, all looking fresh and new.  But once they reach a peak in numbers and the short-lived reproductive frenzy is over then it will not take long for them to start to take on a tattier appearance and finally within a couple of weeks they will have more or less all gone again.  But later in the year the cycle will repeat.

Dirty Frogs

As the dry season progresses then the creatures that live on the forest floor take shelter in the moister damp conditions beneath the leaves that litter the ground during the heat of the day.  As you walk on the trails and your feet disturb those leaves that disturbance will flush the smaller creatures from their hiding places.  You will see displaced skinks, beetles and frogs seeking safe refuge from your footfall and the sunlight.

Rough-skinned Dirt Frog. Anura. Craugastoridae

Rough-skinned Dirt Frog, (Craugastor rugosus)

There are several small frogs that inhabit the forest floor.  These are the rain frogs mostly in the genus: Craugastoridae.  On the forest trails there are two species in particular that you may come across, the Rough-skinned Dirt Frog, (Craugastor rugosus), and Stejneger’s Dirt Frog, (Craugastor stejnegerianus).  The Rough-skinned Dirt Frog, as the name suggests, has a skin covered in many protuberances.  Stejneger’s Dirt Frog on the other hand has a smoother skin and a generally darker area behind the eye.

Stejneger's Dirt Frog. Frogs

Stejneger’s Dirt Frog, (Craugastor stejnegerianus)

Both these species have life histories that have allowed them to decrease their dependency on water and become more terrestrial in habit, certainly in respect to reproduction.  Whereas most amphibians must return to the water to breed, the rain frogs pair up and lay their eggs amongst the leaf litter on the forest floor.  The microclimate beneath the leaves is damper than that above which suits both the frogs and their eggs, it stops them from drying up.  Aquatic egg-laying frogs face the problem of having many predators in the water that will feed on the eggs and the tadpoles.  Rain frogs do not face the same intense predation pressure and can therefore produce fewer but larger eggs.  The larger size of the egg allows full development of the tadpole within a protective gelatinous coating.  A larger amount of yolk is provided which supplies enough sustenance for the frog to complete development and emerge four or five weeks later as a tiny copy of the adult.

Craugastor stejnegerianus. Amphibia.

Stejneger’s Dirt Frog – One too many flashes and It’s Away.

Jumping in Color

Moments after photographing Stejnegers’ Dirt Frog I noticed a tiny black speck of a leaf which moved in a very distinctive and familiar fashion.  The almost indiscernible black dot was a jumping spider.  It had turned to look at me which is how it gave away its presence.  I had to turn the camera lens on it and take same photographs to truly appreciate the amazing little creature I had in front of me.

Jumping spiders belong to the most diverse spider family: Salticidae of which there are more than 5,000 named species around the world.  In Costa Rica there is not a wealth of reference material you can consult in an effort to make an identification.  Sometimes family level is about as far as you can go.

Jumping Spider. Osa Peninsula.

Unidentified Jumping Spider, (Salticidae).

The most distinctive feature of the jumping spiders is the large anterior forward facing eyes.  These give the spider the ability to see things at close range.  They can be seen orientating themselves to watch you.  That is what this one was doing with me.  Unlike their web-building relatives, the jumping spiders hunt their prey down.  Once they identify a potential meal they will pursue it and at the last moment pounce on it, deliver the venomous bite and consume it.

Their visual abilities allow them to use coloration as a cue in mating.  The males may have brightly colored legs and pedipalps to court the females.  This species had bright blue legs and yellow pedipalps.  When a male sees a female he performs a series a ritual dance moves which include lifting his legs in a certain sequence as well as moving in a series of set maneuvers in front of her.  All the while the female is watching, scrutinizing the performance.  One blunder and she will leave having no further interest.  Each species of jumping spider has a very specific dance routine thereby negating the change of courting the wrong type of girl.

Salticidae. Spiders.

Unidentified Jumping Spider. Look at Those Eyes.

Dutch Piper

One of the most distinctive flowers of the forest understory is that of the Aristolochia vines otherwise known as the Dutchman’s Pipe Vine.  As with most flowers the sole purpose is the achieve reproduction through pollination.  Many plants have evolved ingenious means by which to use the flowers as a means to this end.  The Dutchman’s Pipe is one of them.

The flowers are named after their resemble to the carved tobacco smoking pipes used in Holland.  But to a carrion fly they look somewhat different.  Carrion flies are attracted to the fetid odor of rotting flesh.  The flowers of this species of Dutchman’s Pipe, (Aristolochia gaudotii).   give off a scent which mimics the stench of a putrefying body.  The pale yellow base color reticulated with maroon blotches visually emphasize the illusion.

Dutchman's Pipe. Aristolochiaceae.

Dutchman’s Pipe, (Aristolochia gaudotii)

The flies land but find themselves incapable of maintaining a footing on the slippery oily inner surface of the flower and slip down into the interior.  They are unable to make an immediate escape as their exit is blocked by a barrage of downward pointing stiff hairs.  They are trapped.  During the period of vegetative incarceration, the fly struggles violently in order to gain its freedom.  This results in the body becoming covered in pollen.  The following day the stiff hairs wither and the fly finds its exit clear only to fly off and respond to the same trickery.  This time it transfers the pollen thereby pollinating the flower after which it will be released from its temporary floral prison with a fresh coating of pollen.

Aristolochia gaudotii. Carrion Fly.

Dutchman’s Pipe. Looking Down Through the Prison Bars.

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

Observation Lists for Week Ending Monday 16th January.

Mammals

Mexican Mouse Opossum

Nine-banded Armadillo

Greater White-lined Bat

Capuchin Monkey

Central American Spider Monkey

Golden-mantled Howler Monkey

Alfaro’s Pygmy Squirrel

Red-tailed Squirrel

Agouti

Northern Raccoon

White-nosed Coati

Collared Peccary

Birds

Great Tinamou

Great Curassow

Crested Guan

Brown Pelican

Black Vulture

Turkey Vulture

Crested Caracara

Short-billed Pigeon

Orange-chinned Parakeet

Scarlet Macaw

Red-lored Amazon

Mealy Amazon

Common Paureque

Black-throated Trogon

Black-mandibled Toucan

Fiery-billed Aracari

Black-hooded Antshrike

Chestnut-backed Antbird

Golden-crowned Spadebill

Bright-rumped Atilla

Dusky-capped Flycatcher

Great Kiskadee

Rufous Piha

Masked Tityra

Red-capped Manakin

House Wren

Summer Tanager

Reptiles

Common Basilisk

Slender Anole

Golfo Dulce Anole

Asian House Gecko

Central America Smooth Gecko

Litter Skink

Central American Whiptail

Delicate Whiptail

Cat-eyed Snake

Amphibians

Marine Toad

Fitzinger’s Rain Frog

Rough-skinned Dirt Frog

Stejneger’s Rain Frog

Red-eyed Green Tree Frog

Banana Frog

Gladiator Frog

Masked Smilisca

Savage’s Thin-fingered Frog

In The Heat of The Night   Leave a comment


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

It has now been over a month since the unusually heavy rains ceased falling.  During the intervening period of time there has been barely a drop of water and the rain that has fallen conveniently fell overnight.  How quickly the ground has dried though.  The places on the trails where some of the run off was flowing has now stopped completely.  Most the trails have hardened and become firm under foot once again.  The temperatures too have started to creep up and up with midday temperatures hitting the 100⁰ F, (40⁰ C), mark.  At night the sky is clear and bright.  With no cloud cover the temperatures go back down again hitting a pre-dawn low of around 71⁰ F, (22⁰ C).

This is the season when we start to see the trees producing flowers.  Several trees have already started blooming as have some of the orchids.  In the gardens the flowers attract insects, more notably the butterflies.  As you walk down the forest trails, gaps in the canopy allow light to penetrate to the forest floor and these open sunny glades seem to be favored by both dragonflies and damselflies.  Birds are actively seeking out nesting sites.  So, there is no shortage of subjects to photograph as you leisurely wind your way around the grounds.

Night of the Pale Parasols

Sometimes a structure will appear as if overnight that will then catch the observant eye.  They don’t have to be large structures but there will be something about them that make them stand out.  At the side of the road on a bank where the drive had been cut through a hill and only about 4 feet from the ground I noticed a pale umbrella topped cone suspended from an exposed tree root.  Beneath the fibrous parasol the cone was a squat in dimensions but covered with long pale yellow bodies.  Closer examination revealed that each body had a thorax, wings, legs and a head.   I was looking at wasps, more particularly the aptly named Parasol Wasps, (Apoica pallens).

Parasol Wasp. Hymenoptera. Vesperidae.

Parasol Wasp Nest, (Apoica pallens)

The genus Apoica contains but six species.  Strangely for wasps the parasol wasps are nocturnal.  The nest consists of a swarm of workers with several queens and males.  They are active at night engaged in hunting and nest building.  Should you be near one of the nests after sunset and using a flashlight they will readily be attracted to its beam.  During the day the wasps line up, pressed close together and cover the nest but will have no hesitation taking to the air to vigorously defend it should you venture too close.

A Hole Full of Horror

Once the sun has set then the nocturnal creatures that have been hidden away in nooks and crannies by day start to emerge.  Over the past week or two, about half an hour after sundown a juvenile tarantula has been crawling from its web-lined lair hidden in a crack in tree trunk.  Tentatively at first its front legs ease into the open.  Once it is sure the area is safe it slowly creeps into the open and sits head down not too far from its safe refuge and waits for a meal to come by.  Tarantulas do not build webs, they are ambush predators.  They sit and wait for prey to come to them rather than actively hunt food.  A slight tap of the foot on the tree root and this hairy arachnid behemoth quickly returns to the dark recesses of its den.

Tarantula. Osa Peninsula. Felipe del Bosque

Juvenile Tarantula. Unidentified Species.

Tarantulas have a reputation they don’t deserve.  It is unlikely that anyone has died from an American tarantula bite.  The thought of being bitten by a large, hairy spider is what most likely unnerves most people.  Whereas a tarantula bite is relatively harmless for humans, the neurotoxic venom that is injected will subdue and kill insects reasonably quickly.  The female tarantulas are larger in body size and live longer than the males.  A female tarantula can live anything up to 25 years.  On one occasion last week I saw this juvenile catch and eat a long-horned beetle that had ventured too close.  Tarantulas mash the prey with the chelicerae and suck out the juices.

Therasophidae. Mygalomorphidae

Tarantula. Unidentified Species.

It is never a good idea to get too close to a tarantula in case it becomes threatened.  The bite might not pose a problem for a human but the tarantulas have another means of defense.  Using the legs they flick barbed urticating hairs from the body which can become lodged in a potential predators eyes or upper respiratory tract causing severe distress.

Tarantula.

Tarantula. Unidentified Species.

The tarantulas belong to the spider suborder: Mygalomorphae.  They are a rather older evolutionary group of spiders and can be characterized by the chelicerae, (fangs), facing directly down.  Most of the world’s 903 species of tarantula live in the tropics and form the family: Theraphosidae.  The name tarantula is something of a misnomer as they were named after the European tarantulas which belong to the family: Lycosidae or Wolf Spiders, the bites of which supposedly, (again without any basis in fact), would cause people to go into wild convulsions.

Therasophidae

Tarantula. Unidentified Species.

Unravelling the Thread of Death.

There has been one other nocturnal hunter that I have seen over recent weeks that I don’t normally find with a great deal of regularity, the Brown Blunt-headed Tree Snake, (Imantodes cenchoa).  These long, slender serpents become active as the sun sets.  The body is very thin with the neck drawn out into a super narrow section.  Supported at the end is a short head bearing large bulbous eyes.  The body is triangular in section with a light tan base color interrupted along its length by large dark brown saddle markings.

The presence of this snake spells instant doom for small sleeping lizards that may have taken refuge in a “safe” zone at the tip of a leaf.  Normally the amplified movements of a predator along the length of a leaf would immediately alert the lizard to imminent danger allowing it to jump to safety and flee into the undergrowth.

Brown Blunt-headed Tree Snake

Brown Blunt-headed Tree Snake, (Imantodes cenchoa)

Not so with the Brown Blunt-headed master of stealth.  Its light weight and slender form permit movement without disturbance.  The eyes and tongue search for signs of a meal.  The triangular body section give rigidity enabling the prowling snake to reach out into the darkness and snatch the sleeping victim from its secure perch.

The adults can reach several feet in length.  Over the past week I have found and an adult and a juvenile.  The photo is of the juvenile which I found on several separate occasions at different locations around the pond.

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

 

The Savage Death of a Velvet Cat   2 comments


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

Sunny Days are Back Again

The weather has most certainly turned a corner.  After the record-breaking deluge that occurred continually over the course of the last five weeks we now have the opposite situation, no rain.  Not a single drop of rain has fallen over the past week.  The skies have been clear and bright blue.  The sun has been shining brightly.  The temperatures are on the rise.  The night skies have been clear and filled with stars.  Just within the space of seven days, the formerly soft muddy trails have started to harden up.  There are, of course areas where the ground is stiff soft and in places water continues to run off but these are now few and far between.  One trail had a new lake form as the water was unable to run off.  Walking along a familiar path I was finding myself waist deep in water.  I imagined that this new water feature may persist for months before the ground was exposed once more.  I was wrong.  Walking the trail a few days ago, all the water had gone.  The path was very muddy but no longer submerged.

Bosque del Cabo Rain Forest Lodge. Osa Peninsula. Costa Rica.

Zapatero Trail at Bosque del Cabo Rain Forest Lodge.

It was fortunate that the heavy rain stopped as the flowering season for many of the trees commences in December.  Should the trees bloom and then become bombarded with persistent downpours, the flowers can be knocked from the trees before they have been pollinated.  The result of this is a lack of fruit later in the dry season as the plants have not set seed.  There are many animals whose lives depend on the bounteous supply of mixed fruits that comprise their diet that should the flowering and fruiting seasons fail then they simply starve to death.  This happened in 2005 when substantial numbers of Spider Monkeys and Toucans were, quite literally, just dropping out of the trees.  Necropsies carried out by veterinarians showed that they were suffering from very low body fat.  They were starving to death.  Everything looks good at the moment for a bumper harvest as I have seen many trees starting to produce blooms.

Golfo Dulce. Cabo Matapalo. Osa Peninsula. Costa Rica.

The Sun is Shining Over the Golfo Dulce Once More.

Caught in the Eye of a Cat

The frogs are still out in numbers but those numbers will start to dwindle as we head into the dry season.  There are creatures that feed on frogs and they too have been out and about at night, the snakes.  One of the commoner snakes around the pond after sunset is the Cat-eyed Snake, (Leptodeira septentrionalis).  It feeds on frogs at all stages of their life history.  More particularly it searches out clumps of Red-eyed Green Tree Frog eggs which it finds suspended beneath the leaves overhanging the water.  The gelatinous masses are stuck in position and when the tadpoles reach about 7 or 8 days in age, the jelly liquidizes allowing the tadpoles to drop into the water where they complete the initial stage of their life history before emerging as froglets.  Frogs eggs make a perfect meal for the snake, they don’t run away or fight back and are packed with protein.  At the height of the amphibian breeding season, May, June and July, there are so many egg masses that the snakes start to look well fed and bloated.  Now, because there is little amphibian reproduction taking place, the snakes also fish for the tadpoles from beneath the water surface, take froglets as the emerge from the water and if they get the opportunity they will eat the adults too.

Red-eyed Green Tree Frog.

Red-eyed Green Tree Frog, (Agalychnis callidryas)

Agalychnis callidryas eggs

Red-eyed Green Tree Frog Eggs

Cat-eyed Snake

Cat-eyed Snake, (Leptodeira septentrionalis)

Leptodeira septentrionalis

Cat-eyed Snake. Close up.

The Fatal Velvet Kiss

Whereas the Cat-eyed Snakes feed on the smaller frogs, there is a much larger snake which feeds on the larger frogs.  One of the largest frogs in Costa Rica is the Savage’s Thin-fingered Frog, (Leptodactylus savagei).  A huge amphibian might make a satisfying for meal for any number of creatures.  To lower the risk of being predated upon Savage’s Thin-fingered Frog has several defenses.  It has a toxic skin secretion that can cause intense irritation of mucus membranes.  Should this prove ineffective it has a secondary defensive measure.  When it is caught, it issues a loud cry not dissimilar to a crying baby.  More importantly the call resembles the distress call of young caiman.  If there any adult female caiman in the area they charge in to defend their young, which means hopefully as far as the frog is concerned, it can then make its escape as its attacker is attacked.

Savage's Thin-fingered Frog

Savage’s Thin-fingered Frog, (Leptodactylus savagei)

But there are predators from which there is generally no escape.  It is not uncommon to see by the pond at night some substantially large sized Terciopelos, (Bothrops asper).  They are large pit-vipers in the same subfamily as rattlesnakes.  Like rattlesnakes they have a venomous bite that spells certain death for any prey victim it strikes.  An adult female can reach up to 6 feet, (2 meters), in length.  A snake that size demands a big meal and the Savage’s Thin-fingered Frog fits the bill.

Once the sun sets out come the Terciopelos.  They place themselves around the pond where an encounter with a frog is likely.  They are ambush predators; the cryptic coloration of muted browns and greys camouflage them perfectly against the background.  They remain motionless, camouflage works best if it is still.  Frogs, being mostly nocturnal, have large light gathering eyes.  They rely on movement to find food which is usually anything smaller than themselves, particularly arthropods, but sometimes smaller frogs too.  But the only movement they will detect from a hungry coiled Terciopelo will be one that is over in a flash.

Terciopelo. Crotalinae.

Terciopelo, (Bothrops asper)

The pit-viper is not so visually acute especially at night although its eyes will detect close movement.  Once the feeding response has been stimulated then the tongue comes into play, slowly flicking out then in again, each time tasting the air.  The tongue can detect parts per million of scent particles in the air and because it is forked it can pick up the gradient of a scent plume.  You and I may not know what a frog smells like but the snake does.  Then there are the pits that give it the sinister name pit viper.  These lie one on either side of the head between the eye and the nostril.  They are lined with cells that detect minute differences in background infra-red radiation.  They work best at responding to the presence of warm blooded prey such as rodents but their efficiency could also differentiate the small difference in body heat of even a cold-blooded creature such as a frog against the background temperature.

The unsuspecting frog passes by.  The snake has already drawn its head and neck into tightly sprung S-shaped.  The strike happened so fast that it would probably have been unaware, there would have been no time to react, no chance of escape.  As the snake’s head shoots forward and the jaws open, two long hinged fangs that lie flat against the upper part of the mouth now swing down.  They are simply two hypodermic syringes attached to glands that contain virulent life-ending cytotoxic venom.  The fangs puncture the skin like two needles, the force of the bite pushes them deep into internal tissues and organs.  The snake quickly recoils to avoid any retaliatory action by the victim in its final moments, not that a frog could inflict any damage but the bite of a rodent might.  The quantity of venom injected will spell doom and instant death for the unfortunate amphibian.  It probably would not feel anything from this lethal injection, the effects of which would most certainly be instantaneous.

The frog takes one or two steps forward then collapses dead in its tracks.  The snake is in no hurry.  The meal is ready whenever it would care to dine.  Lying patiently in the shadows the Terciopelo begins to smell the air with its tongue once more.  Once it is feels secure in the demise of its victim it slips forward, the tongue constantly flicking in and out over the cadaver.  It is searching for the head.  Snakes have no way of rendering a meal into small pieces and must swallow the prey whole.  Savage’s Thin-fingered Frog is a giant among amphibians, its body larger than the snakes head.  To deal with this inconvenience the snakes lower jaw disengages at the midpoint as do the upper and lower jaws where they hinge together at the side of the head.  Now the snakes gape can accommodate the huge frog body.  The snakes skin is highly elastic allowing it to stretch as it moves forward over the meal and with continuous backward moving S-shaped waves the feast is delivered finally to the stomach.  The snake moves away back into the shadow of the undergrowth where it will lie motionless for some time until it has digested the hearty dinner.

Terciopelo. Leptodactylus savagei

Terciopelo eating a Savage’s Thin-fingered Frog

Payback Time

There are times when even the top predators can become prey.  Where there are snakes then there might be snakes that eat snakes.  Sure enough on occasion by the pond where the Terciopelos lie in wait there is a hunter that actively seeks them out.  A hunter that is immune to the deadly venom.  A hunter that can overpower with impunity its adversary.  That hunter is the Mussurana, (Clelia Clelia)..

The Mussurana is a snake with a solidly muscled body.  It has a beautiful deep gloss grey color which radiates a fabulous deep blue iridescence.  The underside is a soft eggshell cream.  It is a powerful constrictor.  The teeth at the back of the jaws are strong and allow it to hold onto its writhing victim while it throws around it those ever-tightening coils.  This is a non-contest, the Terciopelo has little or no chance.  Finally, it succumbs and expires.  The hunter has become the hunted and the frogs have one less problem in their territory.

Mussurana.

Mussurana, (Clelia clelia)

Philip Davison is a Biologist, Writer and Photographer Based In Costa Rica