Archive for the ‘Jumping Spider’ Tag

Nuts For Giant Green Flags   1 comment


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

Being Yellow and Burning Nuts

Walking along the trails through the forest can sometimes be a visual feast in terms of animal sightings but at other times you may encounter very little at all.  The air is very still and so there is quite often no sound of rustling leaves as when blown in a breeze.  The temperatures are high, not as high as at the top of the canopy, but high enough to make someone more familiar with cooler climes to break into a sweat at the slightest exertion.  The stifling silence maybe permeated by the white noise of calling insects.

At the moment there are many trees in bloom.  The Nance trees, (Byrsonima crassifolia), are currently covered in bright yellow flowers which change to orange after they have been pollinated.  The Nance flowers attract a lot of bees, particularly species of stingless bees native to the area.  Several months from now the trees will bear huge numbers of the small yellow-skinned fruits that are consumed not only by a large number of animals but people too.  The taste is unique and the fruits can be eaten raw or prepared as a dessert or as a refreshing drink.

Nance. Malpighiaceae. Bosque del Cabo. Osa Peninsula. Costa Rica.

Nance, (Byrsonima crassifolia)

One tree that has been flowering for the past month or so and is now producing fruit is the Cashew, (Anacardium occidentale).  It has distinctive large red pear-like fruits beneath which the nut is suspended.  The fruity looking object is the swollen meristem of the actual fruit which is the nut itself.  It is known as the Cashew Apple or Maranon.  This you can eat without concern.  As with the Nance, the flavor is unique.  It can linger for some time at the back of the mouth before fading away.  The nuts are to be treated with a great deal more caution.  Cashew belongs to the same family of plants as poison ivy, Anacardiaceae.  The skin of the nut contains the volatile oil Cardol, which can cause severe blistering when in contact with the skin and more dangerously a burning of the eyes.  Cashew nuts must be roasted or blanched to eliminate the oils.  Even then the utmost caution has to be exercised as the oils can seriously damage the respiratory system, many people who work in the Cashew industry suffer very severe respiratory problems.

Cashew. Anacardiaceae. Philip Davison.

Cashew, (Anacardium occidentale)

While I was looking at the unripe green cashews I noticed another species of Leaf-legged Bug, (Family: Coreidae), that I had not seen before.  A search through the literature would only provide me with the Genus: Acanthocephala.  I have photographed several species in this genus but cannot get them any more specific than that.  This one was feeding on the unripe cashew apple by sticking the dagger-like mouthparts into the flesh and sucking up the juice.

Leaf-legged Bug. Hemiptera. Heteroptera. Coreidae. Bosque del Cabo.

Leaf-legged Bug, (Acanthocephala sp)

Seen As Green With Orange Flags

From here and there bird calls drawn your attention to the distance.  You become attuned to the slight rustles down by your feet.  Further investigation reveals a lizard, one of the whiptails perhaps, scurrying off through dry leaf litter.  Beside you there is a faint buzzing sound, a high-pitched hum.  It is a hummingbird, its wings a blur, coming to scrutinize a piece of red clothing you are wearing.  As far as the bird is concerned this could be a fresh bloom brimming with nectar but no such luck and off it goes.

As I was walking through the forest a quick flash of bright orange caught my eye near the ground.  A male Golfo Dulce Anolis Lizard, (Anolis osae), was displaying to a female.  He catches her attention and tries to gain her favor by flying a bright fiery orange flag, a dewlap, which is a loose piece of skin beneath his chin.  It is supported by a thin rod of cartilage which is attached to the front of the jaw and over which he has muscular control.  The more splendid the dewlap, the better his genetic make-up and the more desirable he will be to father her offspring.  The female is a similar size but lacks the dewlap and has a series of dark diamonds down her back.

Golfo Dulce Anolis. Reptilia. Squamata. Sauria. Polychrotidae.

Golfo Dulce Anolis, (Anolis osae). Male.

Golfo Dulce Anolis. Bosque del Cabo

Golfo Dulce Anolis, (Anolis osae). Female.

While I was lying on the ground photographing the lizards I saw a tiny metallic green fleck moving around.  The movement was jerky as the fleck hopped from one dead twiglet to another.  There was no mistaking that form of movement, it was a jumping spider.  Many of the jumping spiders are minute.  Unless you were looking for them or are familiar with their body movements then it is so easy to miss them.  That would be a shame as they are fascinating little creatures.

Jumping Spider. Araneae.

Unidentified Jumping Spider, (Salticidae). Anterior Eyes.

Normally jumping spiders are inclined to turn and look at you.  This one seemed to be distracted by something else and continually kept its gaze in the opposite direction to me so I could only really photograph its back.  For a fleeting moment it turned to look at me and I managed to get a shot of the huge anterior eyes that the spider relies upon for seeing the prey item that it will actively hunt down.

Salticidae. Osa Peninsula. Philip Davison

Unidentified Jumping Spider, (Salticidae). Dorsal View.

Pussyfooting Around

Mammals, despite their sometimes large size, are notoriously difficult to find.  Monkeys, when active, can make a large amount of noise as they crash through the trees.  They can also be quite vocal.  Coatis and agoutis on the forest floor can be detected b their movement.  Coatis tend to huff and puff a lot as the females with juveniles constantly sniff out any consumable morsel lying in their path.  Agoutis and squirrels can be heard gnawing their way through the shells of various fruit and nuts that form the bulk of their diet.

Cats on the other hand are largely silent.  They are masters of stealth.  Over the past week I have captured videos of an Ocelot walking the Titi Trail.  One of the guests at the lodge crossed the path of a Puma on three different occasions over the last few days.  On one instance the Puma was lying across the trail in front of her and had no desire to move.  She slowly backed away while always facing the cat and finally headed off in a different direction.  The cat could have cared less.  The next day she came across the cat walking down the trail in front of her.  A few days ago the Spider Monkeys were shrieking their cat-specific alarm call and sure enough one the guests staying in the Tropical Garden was lucky enough to see the Puma walking through the forest behind his cabin.

Deceptive Green Stripes and Giant False Bats

The forests, fields, hedgerows and gardens are normally filled with butterflies this time of year and that has been the case.  One distinctive Lepidopteran that has been around in very large numbers over the past month is the Green Urania, (Urania fulgens).  Its striking soot black wings striped with bright metallic green bands make it look so much like one of the swallowtail butterflies that people are surprised when they cannot find it in the butterfly guide books.  It is, in fact, a migratory day-flying moth.

When walking down the forest trails at this time of year people are also fooled by yet another moth.  This moth is so large that it is when it is spooked and takes to the air, its huge wingspan and flapping flight lead people that they are looking at a bat.  This is the largest species of Lepidopteran on the planet, the White Witch Moth, (Thysania agrippina).  If you have the good fortune to see it land you will notice that it orientates itself with the wings up and down.  The light grey ground color of the wings now display in this vertically inclined position darker wavy, zig-zag markings, which if the moth has landed on a pale barked tree, render it almost impossible to see as they resemble crevices in the bark.  Despite they are reasonably common moths throughout Central and South America, very little is known of their life history.

White Witch Moth. Erebidae

White Witch Moth, (Thysania agrippina)

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

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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

 

The Dragon Hunters   Leave a comment


Philip Davison. Costa Rica. Blog. Nature Diaries

Monday 18th January 2016

Hair Trigger

Arachnid. Costa Rica.

Spiders are an amazingly diverse group of animals, the eighth most diverse group of animals of the planet in actual fact.  It doesn’t take long while poking around in the undergrowth to come across a spider.  Some build webs and some don’t but they can all spin silk, the orb weavers having the ability to spin upto seven different types of silk.  The non-orb weavers tend to be ambush predators, remaining motionless in a strategic location where potential prey may wander innocently by unaware of the imminent life threatening danger.  The ambush position could be on the side of a wall, atop a leaf or sitting on a flower head.

Arachnid. Costa Rica.

This Wandering Spider, (Cupiennius sp), was sitting perfectly still on a blank white wall at night.  As many spiders are nocturnal predators the eyes play a lesser part in the identification and capture of a meal but that does not imply the spider is without the means by which to locate the exact location of its prey.  The body, which at first sight looks smooth, upon closer examination can be seen to be covered in hairs of different lengths.  These hairs form part of a battery of sensitive sense organs responsive to touch, vibration and moving eddies of air currents that allow the spider to detect a passing meal in the darkness.

Wandering Spider. Araneae. Ctenidae. Costa Rica.

The majority of hairs covering the body, which give most people the heebie-jeebies with regards to spiders, are tactile and touch sensitive, the stimulus of which will cause the spider to attack or run away.  Between the shorter hairs, particularly on the legs are long fine hairs called trichobothria.  These are super sensitive to the slightest movement in air currents which can be a giveaway for any larger creature passing by which could make a nice meal.  The Wandering Spiders can even detect insects such as moths flying overhead which they jump and grab straight out of the air.

For those more stealthy prey items whose movements are too slow to disturb the air, they cannot avoid causing small vibrations of the substrate and the spiders are attuned to this also.  Around the body but more particularly around the leg joints are slit sense organs which allow the spider to detect any vibrations moving through the substrate upon which it is placed.

Whereas the Wandering Spiders rely on their tactile senses at night during the day there are spiders that actively hunt down their prey visually.  The Jumping Spiders prefer to hunt in full sun.  The most obvious feature are the large anterior eyes with which they can locate and subsequently stalk their victims.  They stealthily approach to the point where the potential meal is within striking distance.  The spider braces itself and then pounce.  The fangs are embedded upon impact, pumping venom into the victim which is held in a death grip by the front pair of legs.

Salticidae. Jumping Spider. Costa Rica.

Hunting the Hunters

The spiders may be highly adapted carnivores with specialized hunting techniques but they too in turn have predators specialized to catch and eat them.  Not the least of these are the giant Helicopter Damselflies, (Megaloprepus caerulatus), the largest damselflies on the planet.  They can be seen flying along the sunlit trails through the forest.  The peculiar motion of the blue/black tipped wings gives the impression of rotating helicopter blades.  What may at first seem like a somewhat erratic flight pattern actually has design.  The more astute observer will notice that they have the ability to fly vertically up and down as well as horizontally in and out.  But what are they seeking?  The large eyes and acute vision are scanning spider webs in front of which they momentarily hover scanning for the silken structures builder.  Once located the spider is grabbed in the legs of the damselfly which goes into reverse gear before biting off the spiders head and legs to finally gorge itself on the soft body parts.

Helicopter Damselfly. Pseudostigmatidae. Costa Rica

The damselflies can be recognized when they alight by the habit of folding the wings together over the body.  Their cousins, the dragonflies keep the wings held out to the sides when at rest. During the day it is not too often that they do rest.  Each individual has a perch from which it frequently takes off to investigate any passing creature that might make a meal or another dragonfly that might prove to be a mate or another dragonfly that might be a rival for that meal or mate.  They make aerial sorties swooping at speed, hovering in place and if unmoved to action return to the perch for a short while before they are off again on another sortie.

Dragonfly. Libellulidae. Costa Rica.

They differ from the more delicate damselflies not only by how they hold their wings but also in the structural placement of the eyes.  Damselflies have two large compound eyes widely separated on either side of the head.  Dragonflies have two large compound eyes that meet together for a greater or lesser part of their margins on top of the head.  However no matter where the eyes are placed they allow for excellent diurnal vision which combined with the unsurpassed aerobatic proficiency make these some of the masterful airborne hunters.

As we move into the dry season the hot and parched conditions stimulate many of the plants into flowering.  This is most certainly true of the orchids.  There are two orchids that can be seen blooming at the moment in the area.  One is a non native terrestrial orchid, the Bamboo Orchid and the other is a native epiphytic orchid.

Orchidaceae. Costa Rica.

The Bamboo Orchid is a native of South East Asia but is planted in many parts of Costa Rica as a beautiful ornamental edging plant.  Bamboo refers to the long erect stalk that resembles that a of a bamboo grass.  The attractive purple flowers appear throughout the year giving a nonstop display of color for the back of a flower border.

Orchidaceae. Costa Rica.

The majority of orchid species in Costa Rica are epiphytic, that is they grow on the outside of trees without harming them.  Generally to see orchids you need to be at the top of the canopy, 88% of Costa Rica’s 1400 orchid species are to be found there.  Many of the orchids flower from December into January but some may be seen flowering at any time of the year.  This particular specimen was found growing close to the ground near the base of a large tree. Due to the diversity of genera and species the identification of orchids, like so many tropical plant and animal taxa, is the realm of specialists.  For most visitors it is enough to see and enjoy the exotic blooms should you be lucky to encounter them.

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

 

Drops of Colored Poison on a Leafy Bed   Leave a comment


Felipe del Bosque Blog February 11th 2013

title copy

The Patter of Tiny Feet

The dry conditions continue but with the bonus of some rain at night which is enough to keep things green.  That hint of dampness is enough to tempt the Halloween Crabs, (Gecarcinus quadratus), out from the dark dank tunnels in which they reside beneath the surface of the forest floor.  They may be land crabs but they breathe through gills which have to remain moist to function effectively, so even though they may have escaped the confines of their aquatic environs and adopted a terrestrial habit, they have not fully adapted to totally dry conditions.  It always remains something of a surprise for people who had never heard of land crabs, and consequently only associate these crustaceans with the rocky coastal shorelines, to find the forest floor crawling with them following a summer shower.

It is not only those creatures in possession of 10 legs that have been spurred into action; the six-legged life forms of the social kind have suddenly become more obvious by their untiring activities.  Leaf-cutter Ants, (Atta cephalotes), familiar to most visitors to Bosque del Cabo due to the mesmerizing lines of slightly wavering fragments of leaf being carried in what seems like a slow moving river of green through the lawns and across the forest floor, have caught a second wind.

Normally at the height of the dry season the Leaf-cutter Ants cease their assiduous cutting and carrying during the daylight hours and recommence once the sun has set.  The dry season in the south west of Costa Rica can quite often result in very little rain for five months of the year and sometimes none at all during February and March.  At this time of year, should the ants cut and carry leaf, the distance over which it has to be transported and the time required to do so can result in the leaf drying out.  If the leaf contains small quantities of toxic compounds, as it dries these may become more and more concentrated thereby constituting a lethal cocktail for the ant or the fungus grown on the leafy mulch that provides staple diet of the ants.  This time of year those leaves delivered to the nest that were tasted and recognized as being unsuitable by the quality control ants are brought back to the surface and dumped on top.  The further we go into the dry season, the higher these mounds of dried leaves will built up around the entrances of the nest.

Leaf-cutter Ant

Currently the waste disposal ants in the colonies seem to be hard at work too.  In many of the nests around the trails excavation has been taking place at a heightened level of activity.  If you were to walk the trails on a daily basis you would see the heaps of earth accumulating in ever increasingly sized mounds.  Take a closer look and you will see the ants whose allocated employment is to remove excavated earth and waste products from inside the nest and bring it to the outside.  Each one is carrying a fragment larger than her own head.  Where the waste tip issues from the side of a hill or bank you will see the friable piles tumbling down, in ant terms each mouthful the size of a boulder, to the base.

Feeding of the Ravenous Hordes

The leaf-cutters are not the only ants that have been stimulated into action over the past week or so.  At various points on several trails long columns of ants moving quickly, deliberately and determinedly have been seen.  These are army ants, (Echiton spp), one of the forests most formidable mini predators.  Army ants have no nest, they are nomadic.  They have to periodically change the location of their temporary headquarters due to the fact that being such a super efficient predator, were they to remain in any one area for a protracted period of time they would deplete the locality of all small forms of life.

They may be encountered in one of two phases of activity; translocation or foraging.  When on the move to a new hunting area the whole colony including the queen is on the march.  There appears to be an endless river of ants streaming across the forest floor, insects in fluid form.  The workers carry the immobile pupae like swaddling aliens in their mandibles.  When virgin territory is reached the army ants ball up, linking their legs together to form a living bivouac, generally somewhere in a sheltered spot such as a hollow log or under a large fallen branch.  The queen moves to the centre, swells up and starts to lay about 60,000 eggs a day.

When the first larvae emerge, they emit a pheromone which causes a change in the behavior of the other workers.  They are stimulated into a hunting response which results in the mustering of half a million murderous assassins swarming through the forest slaughtering all that find themselves so unfortunate to be in their path.  The ravenous hordes surge relentlessly across the forest floor, up trees and scouring every nook and cranny.  The foraging front can be anything up to 60 feet across and 3 feet in breadth.

Army Ant

The ant’s progress will be heralded by flocks of exciting birds gathering as if at a tickertape parade.  You will hear the calls of antbirds, ant-thrushes, antwrens, woodcreepers, woodpeckers and tinamous.  If ever you see Grey-headed Tanagers you will see army ants, they are obligative followers of the army ants.  None of the birds are here to eat the ants.  As the front moves forward so many creatures are flushed, fleeing for their lives only to meet their end in the bill of a hungry bird.

Even if they escape those two terminal hazards, a third gruesome fate may await.  Clouds of parasitic flies, Phorid flies are flying in droves at the head of the advancing front.  The hum of their countless buzzing wings can be heard in the air.  They fly in and lay an egg on any victim attempting to escape the melee of death beneath.  The fickle hand of fate has played them a cruel hand.  They may have escaped mandibles, bills and jaws but the insidious cargo they now carry will now become their executioner.  When the egg hatches the fly maggot will eat its victim alive.

The ants push forward, unrelenting in their pursuit of fresh meat.  Whatever they come across they have, spiders, scorpions, centipedes, beetles, cockroaches, crickets, small frogs, small lizards, small snakes and even fledgling birds, it matters little to the ants.  There is no hiding place; the only choice is to run.  Once found, the prey is overwhelmed in a seething mass of frenzied killers, the ant’s venom laden stingers plunging through the victim’s skin time and time again and within seconds it will have been done to death.  Then it will be butchered on the spot, the slashing mandibles of the ants acting like meat cleavers to dismember the cadaver.  The separate parts of its now mutilated corpse will be carried back along feeder columns from the foraging front to the bivouac to feed the hungry carnivorous larvae.  Once the larvae pupate, the hunting response is turned off and away they go nomadically through the forest until they reach new and rich killing fields from which they will steal the lives of countless unfortunate creatures now dwelling there in blissful ignorance of their rapidly approaching fate.

Swollen With Indignation

Snakes are never the easiest animal life form to find in the forest.  They are ever-present but tend to elude those who want to see them but ironically make an appearance for those who don’t.  As with everything else, once you overcome your aversion to these reptiles, then they become fascinating creatures evolutionarily modified for a unique legless life-style.

One reasonably common snake around the grounds of Bosque del Cabo is the Neotropical Bird-eating Snake, (Pseustes poecilonotus).  They can grow up to six feet or more in length, are a pale blue-grey in color with a yellow belly and quite often a dark head.  If approached they put on a defensive display that involves flattening the neck laterally and turning the head side on so that they look larger than they are.  They are also very snappy snakes and are inclined to readily strike out and bite if molested, a characteristic of both juveniles and adults alike.

Tropical Bird-eating Snake

As the common name suggests, the bird-eating snake feeds on chicks and eggs from nests.  The breeding success of many birds at Bosque is hampered by these lithe predators whose forked tongue allows them to locate the presence of prey very quickly.  Many times around the restaurant area where Cherrie’s Tanagers and House Wrens nest and raise their offspring, it is almost a certainty that before too long the bird-eaters will turn up.

Pseustes poecilonotus

This individual I happened across this week when returning to my cabin.  It was lying across the path and I could see it ahead so just stood and watched for a while.  Its tongue was flicking constantly in and out tasting the air for scent particles.  It moved very slowly its head face down intently following what seemed to be a trail across the ground.  Then it lifted its body and flattened its neck, still its tongue rapidly flicking to taste the air and leaf litter in front as if something was bothering it.  I could see no sign of other life.  It looked like its attention was going to be held in this area for a while so I fetched the camera, lowered myself to the ground and took some close ups of its head before letting it slowly slither off into the undergrowth.

Unexpected Visitors

As the forest is so full of life it is no surprise that things turn up all over the place all of the time.  If I was to sit on the patio of my cabin and take time to look around I will see a myriad of small animals each one of which can capture your attention and then hold you thrall to its actions which can be observed, noted and later analyzed.  It may produce nothing more than an air of idle curiosity but when you delve a little deeper then most subjects however large or small have a fascinating life history and natural biology.

Jumping Spider

This week I was sat reading in the shade and noticed a line of minute ants making their way up and down the outside wall of my abode.  They were little more than moving specks and in typical ant fashion were following in a fairly strict line in both directions.  There was nothing unusual in this per se and my attention was concentrated more on where they were coming from and consequently where they were going to before returning again.

Saltacidae

Off to one side of the ant column was another small dark speck that I could make out as having eight legs.  Tiny as it was, its form and behavior suggested that of a jumping spider, Family Saltacidae.  As I sat watching a small drama unfolded.  One of the ants broke ranks and the maverick spirit took a line of its own deviating away from the main caravan.  This was to be its undoing.  Small prey attracts small predators; nature is red in tooth and claw at every size level.  This ant that had left behind the safety in numbers that comes with a being part of a group had now exposed itself as a target.  That error did not escape the attention of the spider.

Jumping Spider

Despite its minute dimensions, the jumping spider is an evolutionarily adapted hunting and killing machine.  Looking at it face on you will find the front of the head bears huge eyes which in spider terms are visually acute.  It’s not very often that the spider prey will see these eyes as the jumping spiders are as stealthy as a cat.  Once they have singled out their victim they sneak up on it at the last moment launch into the air landing on the hapless prey.  Needle sharp chelicerae inject a powerful immobilizing venom and digestive enzymes which both kill the prey as well as reducing its innards to a soup that the spider can suck from its now dead shell.

That is what happened to the ant.  It would not have even registered that anything was happening.  The attack was lightning fast.  The ant did not know what hit it and it was dispatched in the blink of an eye.  The tragedy played out on the mini stage before me was one of countless such encounters that you can witness all around if you choose to redirect the focus of your attention.

Bat Sac

Despite their numbers, abundance and diversity bats are not always the easiest animals to find.  When you do find a bat, without having it in your hand it may not always be the easiest animal to identify to species level.  Costa Rica has a very diverse bat fauna, 111 species in total of which 80 species live on the Osa Peninsula.

Some bats are so distinctive though that their identity leaves little ambiguity as to what it is you are looking at, the Greater White-lined Bat, (Saccopteryx bilineata), falls into this category.  One morning while walking on the Zapatero Trail with a group of guests, we stopped to watch two bats flitting around between the giant buttresses of the tree.  They would settle momentarily then flit off again to land not so far away.  When they did land it was face down but with the head pushed out at almost a right angle to the body.  This is the characteristic poise of the Greater White-lined Bat.  After the tour had ended I headed back in the hope of getting some photographs.  My luck was in, the bats were still there.  They were not keen on my presence and kept moving but with a little perseverance I managed to capture several images.

Greater White-lined Sac-wnged Bat

The Greater White-lined Bat is one of the sac-winged bats belonging to the Family Emballonuridae.  They are insectivorous bats and are normally communal roosters having one male guarding a harem of one or more females.  Quite often there can be several roosts in close proximity.  They are called sac-winged bats as the male has a small pouched scent gland on the wing in front of the forearm.  This emits a smelly secretion which is used in both territorial and mating displays.  The male can be seen during the course of the day flying up and down in front of the females serenading them with releasing scent from his ‘sac’.

Philip is a biologist, writer and photographer as well as the onsite naturalist guide at Bosque del Cabo Rainforest lodge on the Osa Peninsula, Costa Rica.

www.bosquedelcabo.com

Photo Feature

Localised Poison

There are two species of poison arrow frog to be found at Bosque del Cabo; the Black and Green Poison Arrow Frog, (Dendrobates auratus), and the Golfo Dulce Poison Arrow Frog, (Phyllobates vittatus).  Both are visually unique, both have different calls and they inhabit different habitats so there should be no confusion as to what you are looking at when you find one.

Black and Green Poison Arrow Frog

Currently on the forest floor behind the restaurant where the Creek Trail enters the forest the Black and Green Poison Arrow Frogs can be seen without little difficulty.  You just have to walk ten yards or so then stop and look down by your feet and invariably you will see at least one but often several hopping around.  They are not inclined to be shy either, quite often making their way across the open expanse of the cleared trail or jumping around on the leaf litter to the sides.  The Golfo Dulce Poison Arrow Frogs can be a little more difficult to locate.  They prefer damper habitat and can be found by the creek beds.

Both species have different calls.  The black and green has a high pitched trill which is produced in a very broken stuttering fashion.  The golfo dulce calls with a long unbroken trill.  At certain times of the year you can hear the golfo dulce constantly calling but that is not always going to lead you straight to them.  They are more retiring than their black and green relatives and usually call from under fallen leaves, hollow logs or small spaces in the banks.  Also due to their inherent ability with regards to ventriloquism they seem to be in a different location to where the calls are emanating from.

The poison arrow frogs are diurnal.  For a frog to be found hopping around on the forest floor during the light of day would normally make it an easy target for predators.  These frogs have evolved toxic skin secretions to protect them against predation.  But there is little point having a toxic skin secretion if the predators are not aware of it.  If the frog gets eaten it is too late for both the frog and the animal naïve enough to eat it.  The glowing colors that they sport make them stand out clearly against the background.  If something is so deliberately drawing attention to itself it is not inviting predators to dine on it but rather warning them off.  These are warning colors, aposematic coloration.

Golfo Dulce Poison Arrow Frog

The black and green secretes a lipophilic alkaloid skin toxin which if you get it on your skin can cause burning and itchiness of cuts and scrapes.  Woe betides you if you get it on any mucus membranes such as eyes, nose or mouth.  Put two of these frogs in a bag together and they will die.  The golfo dulce is the most poisonous of the Costa Rican poison arrow frogs.  The skin toxin is a batrachotoxin which poisons heart muscle causing a painful death.  Do not attempt to handle these frogs but by all means admire them for their toxic beauty.

Text and Photographs are taken from the forthcoming book:

The Natural History of Bosque del Cabo by Philip Davison

Temperature and Rainfall

Average Daily Rainfall 0.04 ins.  Total Weekly Rainfall 0.29 ins

Average Daily Rainfall 1.1 mm.  Total Weekly Rainfall 7.4 mm

Highest Daily Temp 96°F.  Lowest Daily Temp 75°F.

Highest Daily Temp 35.9°C.  Lowest Daily Temp 24.8°C.

Species List for the Week

Mammals

  • Mantled Howler Monkey
  • Spider Monkey
  • White-faced Monkey
  • Agouti
  • Alfaro’s Pygmy Squirrel
  • Red-tailed Squirrel
  • Greater White-lined Bat
  • Collared Peccary

Birds

  • Crimson-fronted Parakeet
  • Red-lored Amazon
  • Scarlet Macaw
  • Great Curassow
  • Crested Caracara
  • Mangrove Black Hawk
  • Roadside Hawk
  • White Hawk
  • Crested Owl
  • Spectacled Owl
  • Chestnut-backed Antbird
  • Short-billed Pigeon
  • White-tipped Dove
  • Blue-crowned Motmot
  • Rufus Piha
  • Long-billed Hermit
  • Red-capped Manakin
  • Chestnut-mandibled Toucan
  • Grey-headed Tanager
  • Bright-rumped Atilla
  • Dusky-capped Flycatcher
  • Black-throated Trogon
  • Great Tinamou
  • House Wren
  • Black Vulture
  • Turkey Vulture

Reptiles

  • Barred Ameiva
  • Cat-eyed Snake
  • Central American Smooth Gecko
  • Central American Whiptail
  • Clawless Gecko
  • Four-lined Ameiva
  • Golfo Dulce Anolis
  • Mediterranean House Gecko
  • Pug-nosed Anole
  • Tropical Bird-eating Snake

Amphibians

  • Black and Green Poison Arrow Frog
  • Golfo Dulce Poison Arrow Frog
  • Marine Toad
  • Masked Smilisca
  • Red-eyed Green Tree Frog
  • Savage’s Thin-fingered Frog
  • Stejneger’s Dirt Frog

Butterflies

  • Anartia Fatima
  • Anartia jatrophae
  • Archaeoprepona demophon
  • Caligo eurilochus
  • Colobura dirce
  • Dryas iulia
  • Eueides aliphera
  • Eueides lybia
  • Eurema albula
  • Glutophrissa drusilla
  • Heliconius erato
  • Heliconius hecale
  • Heliconius ismenius
  • Heliconius sapho
  • Heraclides cresphontes
  • Hermeuptychia hermes
  • Morpho helenor
  • Morpho Menelaus
  • Parides erithalion
  • Pierella helvina
  • Pierella luna
  • Pierella argante
  • Phoebis sennae
  • Philaethria dido
  • Pyrisitia proterpia
  • Pyrrhogyra crameri
  • Temenis laothoe

Plants

  • Alamandra  cathartica Flowering
  • Alpinia purpurata Flowering
  • Apeiba tibourbou Flowering
  • Arachis pintoi Flowering
  • Arundina graminifolia Flowering
  • Attalea rostrata Fruiting
  • Bauhinia variegata Flowering
  • Cascabella thevetia Flowering and Fruiting
  • Citrus spp  Fruiting
  • Clusia rosea Flowering and Fruiting
  • Clusia vallerii Flowering and Fruiting
  • Cocos nucifera Flowering and Fruiting
  • Crestentia alata flowering and Fruiting
  • Costus speciosus Flowering
  • Couroupita guianensis Flowering and Fruiting
  • Dypsis lutescens Flowering and Fruiting
  • Etlingera elatior Flowering
  • Ficus citrifolia Fruiting
  • Ficus insipida Fruiting
  • Jacaranda mimosifolia Flowering
  • Heliconia chartacea Flowering
  • Heliconia latispatha Flowering
  • Heliconia pogonantha Flowering
  • Heliconia psittacorum Flowering
  • Heliconia rostrata Flowering
  • Hibiscus rosa-sinensis Flowering
  • Hymenaea coubaril Fruiting
  • Hymenocallis littoralis Flowering
  • Ixora coccinea Flowering
  • Lantana camara Flowering and Flowering
  • Lagerstroemia speciosa Fruiting
  • Morinda citrifolia Fruiting
  • Musa acuminate Flowering and Fruiting
  • Nephelium lappaceum Fruiting
  • Piper auritum Flowering and Fruiting
  • Piper nigrum Fruiting
  • Piper umbellatum Flowering and Fruiting
  • Pleiostachya pruinosa Flowering
  • Plumeria rubra Flowering
  • Psychotria sp Fruiting
  • Stachytarpheta frantzii Flowering
  • Virola guatemalena Fruiting
  • Zammia sp Flowering

 

 

Screening for Aliens   3 comments


Felipe del Bosque Blog September 10th 2012

The Calm Before

It has been another week of sun and showers.  The thunderstorms have still been around but now not every night as has been the case over the past few weeks and they have been further off  in the distance.  Towards the end of the week and over the weekend there was no rain to speak of at all.  So far in terms of precipitation it has been and looks like being one of the drier wet seasons.  But there is still another 2 or 3 months to go before we can say as to whether it was or wasn’t.  For anyone visiting Costa Rica, particularly the Osa Peninsula, at the moment though, if their research had lead them to believe they were in for a soaking, they are going to have a very pleasant surprise.

There is a Light On

One evening when I left my cabin as the sun was setting I forgot to switch off the light.  I was away for several hours searching for animal life around the grounds and when I returned it was to find that the incandescent glow coming from within the 4 walls of my abode had attracted the collective presence of a wide variety insect life.  They had come up against the fine mesh screens covering my windows and there they had come to rest.  Anyone living in unlit areas will be familiar with this phenomenon.

One unusual visitor was a butterfly that must have been flying close by and having seen the light was attracted to its source before settling and becoming dormant.  This was one of the owl butterflies, (Opsiphanes tamarindi).  This is a fairly common species often found in the areas of their larval food plant Heliconias, several species of which my garden grow abundantly in my garden.  They are also crepuscular, more often than not flying at dusk, which this one appears to have been doing before landing on my window screen.  It is noticeable that the trailing edge of the hind wing is missing where a predator must have taken a bite in the area of the eye spot, a deliberate target presented by the butterfly to the predator to direct the bite away from the vitally important head and body.

Owl Butterfly

Looking at the photograph of the full side view, the butterfly would only appear to have 2 legs each side whereas everyone knows that insects have 6 legs, 3 each side.  If you then look at the close up of the head, which the butterfly was so amenable to pose for, you will see that there is indeed a third leg.  The front legs are reduced in size and are held up in front of the eye either side of the proboscis.  They are covered in hairs and give the large and cosmopolitan family of butterflies that this species belongs to its name, the brush foot butterflies, (Nymphalidae).

Opsiphanes tamarindi

A large number of katydids of varying size and species were aggregated on the screen near the owl butterfly.  One weird looking insect, a planthopper was also making its way up the screen.  Both this and the katydids exhibit cryptic coloration that blends them perfectly against the background vegetation amongst which they live.  The katydid’s body is green and leaf shaped whereas the planthopper has its wings bearing a heavy network of dark green contrasting against the lighter green background resembling a mesh of leaf veins.  The border is red with some red spots towards the inside which may serve to suggest some fungal damage or decay.  I stand to be corrected by I think this particular planthopper belongs to the family Flatidae and may be of the genus Lawana.

Unidentified Katydid

Unidentified Planthopper

Tremulous Lawn Gel

One morning while out conducting my daily survey of plants and animals, I noticed in the grass a blob of gelatinous material like a piece of shredded jelly.  The organism was in fact a jelly fungus, Tremella fuciformis.  There is nothing else that actually resembles Tremella so it is easy to identify.  It is generally associated with rotten wood in high humidity but this particular one seemed to growing straight out of the ground. In fact Tremella has the strange habit of parasitizing other fungi that are living saprophitically on decaying roots and branches.

Tremella fuciformis

It is not considered a delicacy many places outside of China where it is grown commercially and consumed in large quantities.  It is also used medicinally in China, more recently for counteracting the harmful effects of radiotherapy.

Not My Stepping Stone

For many months now I have been trying to get a photograph of a large male Basilisk, (Basiliscus basiliscus), that resides at the Bosque pond.  I always see him sleeping at night on a high vertical root of the large Screw Pine growing at the back of the pond but I really wanted to capture him awake at the pond edge.  Every time I got close enough he would take fright and disappear from view at high speed.  On this day though, I could see him sitting in the sun in his usual place at the rear of the pond.  I raised the camera to my eye and hit the release button.  Then I took a few steps closer and shot another picture.  He knew I was there but at this point remained compliant with my desire to capture his image in profile.  I took a few more steps and then took another picture.  I was now at the front edge of the pond and he at the far side, a distance of about 6 feet.  He started to get nervous, lifted his head, I took one more picture and then he was gone.  But at least now I have one decent photograph of him.

Basilisks are iganian lizards that prefer a watery habitat and can commonly be found around bodies of water, creeks and rivers.  They grow to approximately 3 feet in length and are generally found foraging for food around aquatic habitats.  They are omnivores hunting everything from arthropods, fish, amphibians, small reptiles, birds and a wide variety of vegetative material.

Basiliscus basiliscus

The adult males have the distinctive crest at the back of the head as well as the impressive fan that runs down the back and the dorsal surface of the tail.  These features are missing in both the juveniles and females of all ages.  They are known by many as Jesus Christ lizards due to their ability to run across the surface of the water without breaking the surface tension.  The young ones are much more adept at this than are their adult peers who given a good run at it may make some distance before succumbing to the effects of gravity, fall forwards and finally have to swim the rest of the way.

Final Fruit

The bumper crop of mangos, rambutans and star fruit from trees around the grounds that have graced the dishes in the restaurant over the past 3 or 4 months has now dwindled to a few remaining hanging from the trees, their taste long lost with the dying sunny days.  Some fallen mangoes still lie fermenting on the ground under the trees that bore them.  Their fermenting remains are providing one last feast for several creatures.  At night an occasional Crab-eating Raccoon, (Procyon crancrivorus), can be seen eating the fallen fruit, occasionally in the company of the Common Opossum, (Delphis marsupialis).  Kinkajous, (Poto flavus), and some of the monkeys particularly White-faced and Spiders are taking the last remaining fruit in the trees.  One night I saw a female Crab-eating Raccoon bring her 2 new offspring to share in the pungent feast.

Mango with bees

The next day on the ground I could see a fallen mango that had a huge number of bees feeding from the pulp.  The bees were uniformly black and were probably Stingless Bees of the tribe Meliponini belonging to the family Apidae, (which also contains the honey bees).  Again with due care and respect, I managed to get very close for the photograph.

Finally when returning back to my cabin there was a tiny spider on the ground which when it saw me, turned to face me and then gave that look that only a jumping spider can.  The anterior pair of eyes is very large and provides the binocular vision vital to an arachnid that stalks and then leaps upon its prey like miniature eight-legged tiger.

Saltacidae

The hind legs are short and powerful enough to allow the spider to jump some distance relative to its body size.  The front legs are long and designed to catch the prey generally before it knows what has happened.  The jumping spiders always attach a piece of silk before they leap into another creatures oblivion so secure them incase they should become dislodged.

Philip is a biologist, writer and photographer as well as the onsite naturalist guide at Bosque del Cabo Rainforest lodge on the Osa Peninsula, Costa Rica.

www.bosquedelcabo.com

Photo Feature

Almost Stung Again

Last week I posted on the blog some pictures and a short article about Long-waisted Wasps.  If you are careful and look diligently under the leaves of low growing plants you will find that there are a great many paper wasp nests in the area.  I noticed another nest not too far from the restaurant but with some of the Polistes paper wasps attending this one.  The nest was in an awkward place to photograph but with a bit of cautious maneuvering I knew I could access it and hopefully without antagonizing the vengeful little bearers of a venom laden stinger.  I managed to get quite close and obtain some pictures before accidently knocking the leaf under which they were perched.  At one and the same time the aggressive females took to the air, their intentions solely to encourage me to depart, so I made a slow and deliberate retreat and left them to go about their business without further provocation.

Polistes sp         Paper Wasps         Polistes sp

Polistes sp         Paper Wasps         Polistes sp

Just as with Long-waisted Wasps, (which belong to the same family, Vespidae and subfamily, Polistinae), they produce unenclosed nests of chewed up plant fiber composed of one comb with a varying numbers of cells.  There will be one queen whose dominance is asserted over the other females in attendance by fighting.  Initially there may be several females capable of reproduction and as fast as they lay eggs their rivals consume them.  The fastest eater wins and becomes queen.

Paper Wasp

Text and Photographs are taken from the forthcoming book:

The Natural History of Bosque del Cabo by Philip Davison

Temperature and Rainfall

Average Daily Rainfall 0,21 ins.  Total Weekly Rainfall 1.48 ins

Average Daily Rainfall 5.38 mm.  Total Weekly Rainfall 57.68 mm

Highest Daily Temp 89°F.  Lowest Daily Temp 74°F.

Highest Daily Temp 31.7°C.  Lowest Daily Temp 23.0°C.

Species List for the Week

Mammals

  • Howler Monkey
  • Spider Monkey
  • White-faced Monkey
  • Crab-eating Raccoon
  • Kinkajou

Birds

  • Mealy Amazon
  • Red-lored Amazon
  • Scarlet Macaws
  • Great Curassow
  • Pale-billed Woodpecker
  • Black-hooded Antshrike
  • Short-billed Pigeon
  • White-tipped Dove
  • Long-billed Hermit
  • Purple-crowned Fairy
  • Stripe-throated Hermit
  • Red-capped Manakin
  • Chestnut-mandibled Toucan
  • Dusky-capped Flycatcher
  • House Wren
  • Riverside Wren
  • Great Tinamou
  • Black Vulture
  • Turkey Vulture

Reptiles

  • Boa constrictor
  • Cat-eyed Snake
  • Central American Smooth Gecko
  • Central American Whiptail
  • Clawless Gecko
  • Common Basilisk
  • Four-lined Ameiva
  • Golfo Dulce Anolis
  • Terciopelo

Amphibians

  • Banana Frog
  • Black and Green Poison Arrow Frog
  • Fitzinger’s Rain Frog
  • Gladiator Frog
  • Golfo Dulce Poison Arrow Frog
  • Marine Toad
  • Red-eyed Green Tree Frog
  • Smoky Jungle Frog

Butterflies

  • Anartia Fatima
  • Anartia jatrophae
  • Arawacus lincoides
  • Archaeoprepona demophon
  • Cissia confusa
  • Consul fabius
  • Glutophrissa Drusilla
  • Heliconius cydno
  • Heliconius erato
  • Heliconius ismenius
  • Heliconius sapho
  • Hermeuptychia hermes
  • Junonia evarete
  • Morpho helenor
  • Morpho Menelaus
  • Parides erithalion
  • Perophthalma lassus
  • Philaethria dido
  • Phoebis argante
  • Phoebis sennae
  • Pyrgus oileus
  • Pyrrhogyra crameri
  • Siproeta stelenes
  • Taygetis Andromeda
  • Urbanus simplicius
  • Urbanus tanna

Plants

  • Alamandra  cathartica Flowering
  • Alpinia purpurata Flowering
  • Apeiba tibourbou Flowering
  • Arachis pintoi Flowering
  • Arundina graminifolia Flowering
  • Bauhinia variegata Flowering
  • Cananga odorata Flowering and Fruiting
  • Cascabella thevetia Flowering
  • Citrus spp  Fruiting
  • Clusia rosea Fruiting
  • Clusia vallerii Fruiting
  • Cocos nucifera Flowering andFruiting
  • Crestentia alata flowering and Fruiting
  • Costus specioas Flowering
  • Couroupita guianensis Flowering and Fruiting
  • Dypsis lutescens Flowering and Fruiting
  • Etlingera elatior Flowering
  • Ficus insipida Fruiting
  • Heisteria accuminata Fruiting
  • Heliconia chartacea Flowering
  • Heliconia latispatha Flowering
  • Heliconia pogonantha Flowering
  • Heliconia psittacorum Flowering
  • Heliconia rostrata Flowering
  • Hibiscus rosa-sinensis Flowering
  • Hymenaea coubaril Fruiting
  • Hymenocallis littoralis Flowering
  • Ixora coccinea Flowering
  • Lacmellea panamensis  Fruiting
  • Lantana camara Flowering andFlowering
  • Lagerstroemia speciosa Fruiting
  • Mangifera indica Fruiting
  • Musa acuminate Flowering andFruiting
  • Naucleopsis ulei Fruiting
  • Nephelium lappaceum Fruiting
  • Piper auritum Flowering and Fruiting
  • Piper nigrum Fruiting
  • Piper umbellatum Flowering and Fruiting
  • Pleiostachya pruinosa Flowering
  • Plumeria rubra Flowering
  • Psidium guajava Fruiting
  • Psychotria sp Fruiting
  • Stachytarpheta frantzii Flowering
  • Terminalia catappa Flowering
  • Thunbergia grandiflora Flowering
  • Zammia sp Flowering

Slo Mo Drop to a Silken Retreat   1 comment


Felipe del Bosque Blog May 30th 2011

 

 

Continuing Wet

The rains continue to fall and are now building in intensity and frequency.  The daily maximum and minimum temperatures are lowering too.  It may seem hot and humid for anyone not used to tropical conditions with the daytime temperatures reaching 87°F but being out in enduring rainfall can also give the feeling of being colder than it actually is.

Slow Drop

Earlier this year, several female Three-toed Sloths were seen around the grounds of Bosque del Cabo carrying infants.  The young sloths have now been weaned and  gone their separate ways from the mothers, as we have had recent sightings of juveniles at a number of different locations around the grounds.

One morning as I headed out on the Primary Forest tour with a young couple, we took a short detour to see a young sloth that I had seen earlier.  Little more than an hour before, as I walked through the forest, there was a juvenile Three-toed Sloth about 4 feet off the ground on the side of a small sapling.  When we returned, the youngster had made its way up to the top of the tree.  The people I was with were happy to take photographs of it slowly trying to move from the top of the tree from where it had nowhere else to ascend, into the branches of a neighboring tree.  In slow, typically languorous fashion it reached out take hold of a thin tree limb.  As it tried to transfer its weight, the branch snapped and the young sloth came tumbling down from about 20 feet up.  The young couple were concerned as to its chances of surviving a fall of that distance, especially as it hit several other branches on the way down.  If nothing else they are pretty resilient, so I picked the sloth up off the ground, and placed it back on the small trunk and up it went, none the worse for the experience.

Sloths are leaf eaters with a very low basal metabolism.  Leaf, at the best of times yields very little energy, hence the sloths relative lack of rapid mobility.  During periods of the year when there is no fresh leaf available for food, just old, fibrous, almost indigestible leaf, coupled with a temporal, an extended period of heavy cloud cover, lower temperatures and no sunlight, the sloth can succumb to a condition akin to hypothermia.  The sloths low metabolic rate, with none of the sun’s energy to help kick along the digestive processes, makes them soporific and it is at this time of year that they fall from trees, occasionally not being as fortunate as our youngster, they don’t survive the drop.

Philip is a biologist, writer and photographer as well as the onsite naturalist guide at Bosque del Cabo Rainforest lodge on the Osa Peninsula, Costa Rica.

www.bosquedelcabo.com

 Photo Feature

Following The Silk Trail

Spiders provide an endless source of fascination.  They don’t top everyone’s list of favorite creatures, but looked at objectively, every aspect of their lives is simply incredible.  Over the past week as I have been walking around the lodge grounds, I started to see variations on an arachnid theme.  I don’t know what made me suddenly seem more aware of our eight legged friends, possibly being out late one night and seeing an Ogre-faced Net-casting Spider did it, but I was inspired to go and get the camera for a closer look.

The first things I thought I might get some shots of were the webs.  Webs, their construction and use, would provide enough material for a book in itself.  Although not obvious to the untrained eye, the web of each species of spider is unique to that species. The webs are made of silk, which in itself is an amazing material.  Silk is a long chain protein molecule.  In the silk glands of the spider it is a liquid, when the spider starts to spin, it becomes a solid, a process that cannot be reversed.  Orb spiders have the ability to spin 7 kinds of silk, of which, at least 4 varieties are used to construct the typical orb web.

Golden Orb Spider

The silk is produced by glands in the spider’s abdomen which, under increased blood pressure, exude the liquid silk.  The legs of the spider pull the silk, aligning the molecular structure, and the silken strand is created.  Take a close look at the hind end of a spider and you will see the spinnerets which produce the silk.  These are composed of a collection of muscular nozzles which can alter the properties of the strand, making it thicker, stronger and more elastic depending upon the purpose of its use.

Golden Orb Spider Spinnerets

Orbs are not the only type of web though; there are tangle webs, sheet webs, dome webs, lace webs, basket webs, reduced webs and finally the single strand that is the web of the Bolas Spider.  Spiders can also use silk to tie two leaf edges together when making a shelter. It is highly unlikely that for any day in the life of a spider it is not producing, using or in contact with silk.

Micrathena sp

Having said that, not all spiders make webs, some are active hunters while others are sit and wait ambush predators.  A typical ambush spider seen all around the grounds of Bosque at night is the Wandering Spider.  They can be found lying motionless on the leaf surfaces at night waiting for an unsuspecting small animal, be it another spider, insect, small frog or lizard, upon which they pounce, inject with venom and consume.

Wandering Spider

Crab spiders will sit, quite often superbly camouflaged, on or near a flower head.  Approaching insects are totally unaware of the hidden danger lurking amongst the blooms and as they land the spider lunges forward and captures its prey.  This particular individual I only noticed because of the silk securing the two edges of a bent leaf making a shelter.

Crab Spider Shelter

Crab Spider

There are Jumping Spiders which tend to be very small.  One of the four pairs of eyes, the forward pointing pair, are very large, giving the spider excellent sight and good depth of vision.  Whereas Wandering Spiders tend to be nocturnal, the Jumping Spiders are diurnal.  They are stealthy sneakers, creeping up on the intended insect victim, and then jumping, anything up to 20 times its own body length to land on top of its prey.

Jumping Spider

tangle webs are created by attaching a complex of silken lines between two leaves lying horizontally one above the other.  If an insect flies into the tangle it becomes stuck to the threads which break from their lower attachment, then recoil upwards towards a denser mass of threads, effectively immobilizing and holding the prey bound within its core until the spider arrives to dispatch it.

Tangle Web

Webs are familiar to most people, strung as they are in almost any location, both inside and out.  The silken threads composing the web are covered in tiny droplets of glue which, in a similar fashion to the tangle web, holds the insect momentarily captive until the spider quickly locates it, wraps it up in a different kind of silk and finally delivers the lethal injection before consuming it.

Silver Orb Spider

Text and Photographs are taken from the forthcoming book:

The Natural History of Bosque del Cabo by Philip Davison

Temperature and Rainfall

Average Daily Temp High 87°F.  Average Daily Temp Low 74°F.

Average Daily Rainfall 0.51ins.  Total Weekly Rainfall 3.58

Average Daily Temp High 30.4°C.  Average Daily Temp Low 23.2°C.

Average Daily Rainfall 13.0 mm.  Total Weekly Rainfall 91.2 mm

Species List for the Week

Mammals

  • Howler Monkey
  • Spider Monkey
  • Capuchin Monkey
  • Red-tailed Squirrel
  • Agouti

 

Birds

 

  • Red-lored Amazon
  • Scarlet Macaw
  • Great Currasow
  • Roadside Hawk
  • Lineated Woodpecker
  • Black-hooded Antshrike
  • Chestnut-backed Antbird
  • Short-billed Pigeon
  • Red-capped Manakin
  • Chestnut-mandibled Toucan
  • Great Tinamou
  • House Wren
  • Black Vulture
  • Turkey Vulture

 

Reptiles

 

  • Barred Ameiva
  • Four-lined Ameiva
  • Green Iguana
  • Golfo Dulce Anolis
  • Clawless Gecko
  • Mediterranean House Gecko
  • Cat-eyed Snake
  • Terciopelo
  • Tropical Bird-eating Snake

 

Amphibians

 

  • Marine Toad
  • Red-eyed Green Tree Frog
  • Banana Frog
  • Masked Smilisca
  • Milky Frog
  • Small-headed Frog
  • Smokey Jungle Frog
  • Stejneger’s Dirt Frog
  • Black and Green Poison Arrow Frog
  • Fitzinger’s Rain Frog
  • Tink Frog

 

Butterflies

 

  • Anartia fatima
  • Cupido comyntas
  • Detritivora gynaea
  • Dryas iulia
  • Eueides lybia
  • Heliconius cydno
  • Heliconius erato
  • Heliconius hecale
  • Heliconius ismenius
  • Heliconius sapho
  • Heraclides cresphontes
  • Hermeuptychia hermes
  • Hyalyris excels
  • Laparus doris
  • Magneuptychia libye
  • Mechanitis polymnia
  • Morpho helenor
  • Morpho Menelaus
  • Pareuptychia ocirrhoe
  • Parides erithalion
  • Philaethria dido
  • Phoebis sennae
  • Pierella luna
  • Pyrgus oileus
  • Urbanus simplicius
  • Urbanus tanna

 

Plants

 

  • Astrocaryum Palm Fruiting
  • Black Alligator Tree Fruiting
  • Calabash flowering and fruiting
  • Clusia Vine Fruiting
  • Monkey Comb Tree Flowering and Fruiting
  • Candlestick Plant Flowering.
  • Cannonball Tree Flowering
  • Figs Fruiting
  • Inga Fruiting
  • May Tree Flowering
  • Manglillo Fruiting
  • Nutmeg Fruiting
  • Psychotria Fruiting
  • Rosa del Monte Flowers
  • Rubber Tree Fruiting
  • Santa Maria Flowering
  • Stinky Toe Fruiting
  • Ylang ylang Flowering

 

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