The dry season continues unrelentingly. The daytime temperatures are still hitting the 100⁰F, (40⁰C), mark. There was a fleeting downpour one lunchtime that lasted little more than an hour. That same evening, with the momentary increase in humidity as the ground remained damp, the Halloween Land Crabs responded by emerging from their burrows in large numbers. The following night however they were once again noticeable by their absence as whatever precipitation had fallen once again evaporated and the bone-dry situation persisted.
The gardens are visibly showing signs due the effects of the extreme heat and arid conditions. The lawns are now more or less devoid of any greenery, all that exists is a broad area of parched brown burnt grass. The herbaceous plants are suffering too. Many of them have lost leaves and if they have not fallen over and died then they are most certainly looking limp and in distress. They will have to wait for a while yet for any relief as the rains do not normally start until mid-April or May.
Many of the creatures I photograph are found serendipitously. I rarely go out to photograph something specific unless it is a plant or animal that I have seen while out walking that I think will remain in place until I return with the camera. The weekly blog is written from the point of view of accidental discovery. I never know what I am going to write about until I find it.
This week I came across two different species of bugs on the same day. One was a Big-legged Bug of the family: Coreidae and the other was a stinkbug nymph of the family: Pentatomidae. The term big-legged bug perfectly describes these heteropterans. The femur of the rear legs is stout and bear spike-like projections. The tibia is flattened. They are herbivores and can sometimes become a pest feeding in large numbers on crops. This individual belongs in the genus: Acanthocephala but I am not sure of the species. There are twenty-four named species of Acanthocephala of which seven species live in Central America.
Big-legged Bug, (Acanthocephala sp)
The stinkbugs are named after their ability to produce a repugnant smelling secretion from glands in the abdomen. They are sometimes called shield bugs due to the body shape. I found this particular species in the nymphal stage. There were several of them living gregariously together sucking sap from the leaves of a passion vine. The stinkbugs go through five nymphal stages before becoming adults.
Stinkbug, (Family; Pentatomidae)
Flower and Fruit
The Guacima tree, (Gauzuma ulmifolia), is found growing at the forest edges here at Bosque. It is easy to miss the flowers but the fruits are more visible. Currently they are lying all over the ground in the areas where the trees are growing. The fruits are very hard and are only occasionally fed upon by White=faced Monkey. The tree is more commonly found growing along roadsides where livestock feed on the fallen fruits.
Guacima, (Guazuma ulmifolia). Fruit.
A tree that is flowering throughout the forest at the minute is the Jacaranda, (Jacaranda copaia). The bright lilac-colored bell-shaped flowers are covering large areas of the forest floor like a violet carpet. Jacaranda as well as Guacima are both native to Central America.
Jacaranda, (Jacaranda copaia). Flower
The Mayo Trees, (Vochysia ferruginea), have started to flower. The crowns of the mature trees in the canopy are covered in an umbrella of bright yellow. The Mayo Trees are so named because they supposedly flower in Mayo but that has not been my experience in the last seventeen years of living in Costa Rica. Soon the canopy will be awash with patches of bright pastel colors like a giant watercolor painting.
Philip Davison Is a Biologist, Writer and Photographer Based in Costa Rica
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.
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.
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.
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, (Heliconius cydno)
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, (Anisoscelis flavolineata)
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.
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.
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
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.
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
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, (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.
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. Caterpillar
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.
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, (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, (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, (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 Anole, (Anolis osae)
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, (Anolis pentaprion)
Philip Davison is a Biologist, Writer and Photographer Based in Costa Rica
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.
Alcandra Skipper, (Gorgothion alcandra)
Barred Yellow, (Eurema daira)
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.
Pochote Flower, (Pachira quinata)
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.
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.
Perfumed Passion Vine Flower, (Passiflora vitifolia)
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
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.
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.
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.
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.
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.
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, (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, (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.
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.
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.
Unidentified Jumping Spider. Look at Those Eyes.
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, (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.
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.
Mexican Mouse Opossum
Greater White-lined Bat
Central American Spider Monkey
Golden-mantled Howler Monkey
Alfaro’s Pygmy Squirrel
Golfo Dulce Anole
Asian House Gecko
Central America Smooth Gecko
Central American Whiptail
Fitzinger’s Rain Frog
Rough-skinned Dirt Frog
Stejneger’s Rain Frog
Red-eyed Green Tree Frog
Savage’s Thin-fingered Frog
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 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.
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.
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. 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.
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, (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