Archive for the ‘Argiope argentata’ Tag

Spiders: The Eighth Level of Diversity   2 comments


Wildlife, nature, fauna and flora of Costa Rica.

The rainfall of April, May and June from 2016 was more or less exactly the same in terms of monthly totals for the same periods in 2107 but this week has proved to be very wet.  The rain has been incessant, both day and night with very little of the sun having been seen.  A total of 15 inches rain fell and now the creek is running quite fast, so no water problems this year.

Spiders:  Not Everyone’s Favorite

I have to admit that many people I take out would rather just walk straight past spiders and ignore their presence.  Some people, despite their revulsion, are intrigued by their natural history, they are, after all, fascinating creatures.  I find them interesting to observe, understand and photograph.  They are mini carnivores with a wealth of different life histories.  They are also ubiquitous, they can be found just about anywhere on the planet, (apart from maybe Antarctica), and in abundance.  It is often stated that at no point in your life are you any more than six feet away from a spider and I can demonstrate the proof of that fact quite adequately every evening when I take people on the night walk.

There are approximately 40,000 species of spider distributed worldwide which makes them the eighth most numerously named group of animals on the planet.  Although they are all, (apart from possibly one species), carnivores and use venom to subdue and kill their prey, they are not dangerous to humans expect for those well documented species, the numbers of which you could count on the fingers of your hands.

Spiders divide up into two broad groups.  The first group are the Tarantulas, Trapdoor Spiders, Funnel-web Spiders and the Purse-web Spiders.  The second group are all other spiders and they are subdivided depending of the mode of food capture.  There are the Web Weavers; those spiders that produce the familiar silken webs but those webs also come in different forms.  There are Orb-web weavers, Sheet-web Weavers, Tangle-web Weavers and Lace-web Weavers.  Then there are Ambush Spiders such as Crab Spiders as well as Wolf Spides, Huntsman Spiders, Lynx Spiders, Fishing Spiders, Spitting Spiders, Jumping Spiders, Woodlouse Hunters and Wandering Spiders.  All in all, if there is a way of catching prey, then spiders have it covered.

A Living Tetrahedron

I noticed this spider last week crossing the road in front of me.  The bright yellow coloration was in marked contrast to the grey grit across which it was scurrying.  As I bent down to take the photograph, the spider went into a defensive posture and tucked its legs up against the body.  This made it easy for me but gives it a somewhat unnatural pose.  I think this individual must have fallen from an overhanging tree branch, maybe escaping becoming a meal for a larger animal.  Being bright yellow might work to disguise it amongst foliage but not against the dark grey of the road surface.

Rainforest arachnid. Rainforest areneae. Costa Rica spider.

The strange tetrahedron shaped body of this unidentified spider

You can gauge how small the creature was by the size of the grit next to it which is only about 1mm across.  When looked at close-up though you can see the spider is remarkably shaped.  The body is drawn up into an almost polygonal shape, a tetrahedron, rounded along its edges.  There are raised red nodules along the rear edge.  You would think that these would make it an easy spider to identify, but no such luck.  Extensive searching has not provided an I.D.  I would hazard a guess that it is one of the many tropical orb-weavers.  If anyone has a name I would be very grateful to receive it.

A Silver Orb in the Sun

Further down the road, in an open sunny area I saw a large web with the weaver sitting in the center, its eight legs forming a cross of four pairs.  Because of its location I could not get around to the opposite side to get a dorsal view so had to settle for the ventral view.

This species I had seen before, on numerous occasions.  This was a Silver-orb Spider, (Argiope argentata).  The fluting of the body rim along with the black and yellow tiger striping of the legs are examples of disruptive form and coloration which serve to make the creature less spider-like.  It is an effective form of camouflage used throughout the animal kingdom.

Rainforest Silver-orb Spider. Rainforest animals. Argiope argentata Costa Rica. Spider web. Spider silk.

Ventral view of a Silver-orb Spider, (Argiope argentata)

The web itself is constructed from silken threads.  Silk is an amazing material and deserves a book devoted solely to that subject.  Silk is both elastic and strong.  Orb-weavers can produce upto five different kinds of silk, each variety having a different use.  Silk is produced as a liquid in the silk glands, it is then secreted from the spinnerets where it is drawn out by the hind legs into the long threads.

To construct the web, the spider first has to create a framework of threads radiating from the center.  Then starting on the outside, it spins a spiral thread, round and around towards the center.  The spiral silk is coated in a sticky hygroscopic glue which serves to catch any prey item unfortunate enough to fly or fall into it.  The elasticity of the threads takes out the kinetic energy of an impacting large flying insect and stops the web from breaking.  Silver-orb Spiders are fairly large and consequently so are their webs.  They are reasonably common in the area so it does not take too much effort to find them.

Hidden Death Dealer in the Flowerheads

Sometime ago I noticed a butterfly behaving in a very strange way on one of the Lantana flowerheads.  Further investigation revealed the butterfly was dead and the unusual movement was being caused by it being manipulated within the legs of a small but efficient killer, a Crab-spider.

Crab spiders are small squat spiders and receive their name due to their ability to walk sideways as well as forwards and backwards.  They are ambush predators.  Some have the capability of changing color over a period of weeks to match that of the flower where they are sitting and waiting for a prey item to land.  In this case the victim was a White-banded Fatima (Anartia fatima).

Rainforest Crab Spider. Unidentified Thomisidae sp Costa Rica.

Unidentified Crab Spider captures, kills and eats White-banded Fatima

The butterfly would have been totally unaware of the lethal assassin’s presence.  As soon as it landed to take a feed of nectar, the longer and stronger front two pairs of spider legs would have grabbed it.  The butterfly’s wings would have been beating frantically but taking flight was no longer possible.  At the same time, a powerful venom would have been injected through the spiders fangs into the butterfly’s body killing it almost immediately.  The spider holds on until the venom has done its work.  The wings stop beating and the now lifeless butterfly is motionless.  Digestive enzymes injected with the venom liquidize the butterfly’s innards which the spider will then suck out as a soup.  It will then let the dry and drained husk of the victim fall to the ground.

To find crab spiders you have to search diligently among the flower heads.  Sitting patiently without moving and having the same color as their ambush position makes them difficult to spot.  Sometimes the only clue to their presence is the telltale sign of strange behavioral anomalies of their victims.

Rainforest Crab spider. Thomisidae Costa Rica. Rainforest animals. Rainforest Spiders.

Death hidden by beauty. Crab Spider waits at tip of a flower for a meal to arrive

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

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Hidden In The Full Light Of The Sun   5 comments


Felipe del Bosque Blog February 11th 2013

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Arranging Dried Flowers

There was no rainfall at all over the past week.  That is not unusual for this time of year; February and March are normally the two driest months.  The grounds of Bosque and the surrounding forest still look lush despite the lack of rain.  One of the features that I use to indicate just how dry it the conditions are, is the creek.  At the moment, although the level is down, the water is still flowing quite freely.

More of the trees have started to flower.  Some of the Ajo Trees, (Caryocar costaricense), are already flowering for a second time this season.  The Pochote trees, (Pachira quinata), are dropping their distinctive shaving brush flowers.  The fruit of the Milky Tree, (Brosimum utile), also known as breadnuts, are raining down from the canopy where ever these trees are found.  The monkeys are particularly fond of them but being wasteful feeders take one bite of the fleshy rind and throw the remainder away.  The Monkey Comb, (Apeiba tibourou), is littering the forest floor in areas with its distinctive spiny ball-like fruits.

Rarely What It Seems

Costa Rica is a very biodiverse country.  It doesn’t matter whether you are talking about families of plants or animals you will find the numbers staggering in comparison to a temperate country.  All of that diversity is held within a country that covers only 0.03% of the earth’s land surface.  Even with well studied groups such as beetles or butterflies and moths it is not always easy to identify individuals down to species level.  You could spend your life in this special little country and dedicate yourself to trying to make an inventory of the life that exists here and you would barely scratch the surface.

When something new turns up it is always exciting.  I am continually thrilled to find a species that I have never seen before.  It is all the more satisfying when I find a species that has not previously been recorded on the Osa Peninsula or more so if it has only been recorded a few times in Costa Rica.  Occasionally a weird creature will turn up that I have never seen any species of anywhere before.  That is what happened earlier this week.

I was heading out to one morning to meet the guests that were about to go for a walk through the forest with me.  On the ground outside my cabin, making its way at a fast pace between the fallen dead leaves littering the pathway was a strange looking scorpion.  I had not seen anything like it but there was something about the way it was moving that just did not seem right.  Every time I lifted a leaf it would quickly run under yet another.  Finally I managed to wrangle it into an open area for a closer look.  I could see now that it was not a scorpion but appeared to all intents and purposes to be a spider mimicking a scorpion.  Its front two legs seemed to be held out in front like a pair of pincers and the body was elongated but lacking the segmented tail and the sting.  It was like no spider I had ever seen before.  I was late for my tour so placed a jar over the top of it so that I could photograph and hopefully identify it when I returned.

I arrived back at my cabin in the afternoon and could now scrutinize more closely the strange creature I was holding in an insect jar in front of me.  I had been pretty sure it was not a scorpion but rather a spider until under magnification I could see it most certainly was an arachnid but astonishingly not something I had been expecting to see.  It had eight legs and what I had originally mistaken as pincers I could now see were two blunt tipped pedipalps.  This was a Solifugid or Sun Spider.  They are not actually spiders but a separate Order: Solifugae within the Class: Arachnida.  The elongated fiery orange prosoma, (head), was tipped with two fearsome looking chelicerae.  Two black spots marked the eyes.

Solifugid

Solifugae is Latin for hiding from the sun which is strange given the common name of these creatures is sun spider.  They are carnivores and actively hunt small arthropods.  Some desert living species can grow to an impressively large size, (not as large as newspapers would have you believe though).  I remember being both fascinated and horrified by some preserved specimens my grammar school biology teacher liked to terrify the kids with.  Those chelicerae are perfectly capable of delivering a nasty nip.

Despite extensive searching I could find almost no literature regarding solifugids in Costa Rica.  I have been visiting the country for over 20 years and lived here for 13 years and this is the first species of solifugid I have seen.  At least I have the photographs so that future investigation may reveal a little more about it but for now it will just have to remain a nameless enigma.

What is the Meaning of This

Spiders are very prevalent at the moment both around the grounds and in the forest at Bosque.  The two most obvious spiders seen largely due their size are the Golden-orb Spider, (Nephila clavipes), and the Silver-orb Spider, (Argiope argentata).  You don’t have to wander too far from the confines of your cabin or the restaurant to locate either of these two species.  The Golden-orb Spider has a very obvious web, the orb, made from a bright yellow silk which gives it the name.  It is not too much of a stretch of the imagination to assume the Silver-orb Spider has a white colored silken orb.

There is one very distinctive feature of the Silver-orb Spider’s web that makes it even more visible.  Scattered at intervals throughout the vegetation you will see what appear to be large white X shapes.  Further investigation will lead you to find that these X shapes are in the centre of a spider web.  More often than not you will see the spider responsible for the construction of the X sitting right at its centre, the Silver-orb Spider.

Silver-orb Spider

The inclusion at the centre of the web is known as a stabilimentum and there is no definitive answer as to why the spiders spin them.  There are several theories, any one of which may be correct.  Many spiders at the end of every day take their webs down and build a new one just before sunrise.  There are other spiders that leave their webs permanently in place, the Silver-orb Spider being one of them.  To prevent birds flying through the web thus destroying it, getting covered in sticky silk and causing the spider to construct a new web, the stabilimentum may mark the position of the web to prevent that from happening.  I have no data to show the frequency with which birds fly through non stabilimentum webs.  The spider is an arachnid; it has eight legs which divide up quite nicely into four pairs.  You will generally see the spider sitting in the centre of the web with one pair of legs aligned along the four bars of the cross.  If the sun rises and the light hits the cross the spider will take shelter behind the cross.  If you disturb the spider it will disappear from in front of your eyes to be found later hiding behind the cross.  The silk the spider uses to make the stabilimentum is highly reflective of ultra violet light.  Insects are attracted to a source of ultra violet light and so the web now becomes an active trap luring the insects in.  Birds, unlike ourselves, see ultra violet and so the X is not white but ultra violet to the bird’s eyes.  Each of the theories has its own credibility but no one has yet solved the puzzle of the stabilimentum.  It could be that each and every one of the theories has some merit.

Argiope argentata

Unexpected Visitors

Last week I mentioned the myriad of animals that visit my cabin day and night.  I am never short of house guests.  I returned one night last week to find a handsome hawk moth clinging to the mesh screening of the cabin door.  Hawk moths belong to the Family Sphingidae.  They are reasonably easy to recognize to family level due to the long narrow forewings which tend to be triangular in shape.  They are fairly longed lived as adults in comparison with some other Lepidoptera.  In Costa Rica there are somewhat in the region of 145 species hawk moth.  I was not sure what particular species it was that had decided to grace my cabin with its presence but I am always happy to see something new, photograph it and hope to make the I.D. sometime later.

Unidentified Hawk Moth

Ginger Snap

Around the grounds of Bosque you will find many plants growing that are not native to the country.  The gardened areas are just that – gardens containing exotic tropical ornamental plants from far flung areas of the globe.  They are there as decorative specimens, a lot of them grown for their fabulous flowers, perfumed scents or the amazing leafy displays.

Growing in borders near the bar and swimming pool are a variety of prettily flowered and heavenly scented plants one of which is the White Ginger, (Hedychium coronarium).  Due to its predilection for damp shady areas it is grown in areas where other showy scented blooms will not.  But despite its attractiveness and sweet smell, it is regarded in many parts of the world as an invasive plant.  It is a member of the ginger Family Zingiberaceae and originated in the Nepalese Himalayas but is now grown extensively almost everywhere with suitable conditions.  Where growing conditions are right it can spread from underground rhizomes and can become a weedy pest very quickly.  Here at Bosque it is solely confined to the flower beds around the swimming pool.  The sweet perfume that it issues at night brings in hawk moths which hover in front of the flower and use their long proboscis to imbibe the nectar and subsequently transfer the pollen.  Given that information then perhaps its other name of Butterfly Lily would be more appropriate.

White Ginger

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

Side Step

Last week while walking the Zapatero Trail with a couple of guests, we were approached by two other visitors to the lodge who were walking on their own slightly in front of us.  On the path they had spotted a venomous snake, a Terciopelo, (Bothrops asper), and had wanted to warn us of its presence in the middle of the trail.  When we arrived at the spot where the snake lay coiled on the ground I could see that it was only a juvenile and its position tucked in at the base of an exposed tree root crossing the width of the trail suggested it posed little danger to anyone.  So I decided to leave it without disturbing its peace and return later in the day to take its picture.

Terciopelos are ambush predators and will sometimes just sit in the same position for days on end without moving.  The small ones feed more on frogs, lizards and small rodents while the adults prey on much larger rodents.  The adults can get to over 7 feet, (2 meters +), in length.  They are very cryptically colored, the body having a base of grey with the dorsal surface suffused with a mottling of soft browns.  Along the sides are dark brown triangles that meet at the apices.  These triangles are outlined with a pale cream border that when viewed from above give the impression of a series of X’s running down the snakes back.

Terciopelo

The Terciopelo is sometimes referred to as the Fer-de-Lance, which strictly speaking is a South American snake Bothrops atrox.  The name is French and translates into iron lance head due to the obvious triangular shape of the head.  The head is dark above and pale below; in some specimens the head is yellow below giving it the other colloquial name, Barba Amarilla or yellow beard.

The Terciopelo is a pit viper.  The head houses everything the snake needs to detect its prey and then deliver that deadly venomous cocktail that will be injected resulting in almost instantaneous death.  The eyes with their elliptical pupils allow the snake to see but most snakes do not possess the visual acuity equal to that of some other predators such as birds.  But what they lack in respect of eyesight they more than make up for with two other pieces of sensory apparatus.  The tongue is essentially an organ of scent in snakes. It can pick minute quantities of scent particles in the air or on the substrate.  Due to the tongues forked structure the snake can pick up a scent gradient in the air, it can detect from which direction the prey or potential predator is moving.  They sometimes locate and sit on a rodent trail which is more than likely where its prey is going to come by at some point.  Between the eye and the nostril is another depression on the head which houses sensory organs that allow the viper to detect small changes in background infra red radiation.  This is the characteristic pit which gives pit vipers their name.  Any approaching mammal or bird will be registered as a signal change suggesting dinner has arrived.

Bothrops asper

This particular Terciopelo was a young female.  She looked liked she was well fed as her body was quite plump.  I placed the tripod on the ground in front of her, composed the shot and got the photograph.  I then moved around to the side and got the full body profile picture.  Despite the fact that I was shooting with a lot of flash the snake never flinched.  I was only a few inches away from it.  The whole point of the cryptic coloration, the camouflage, is that you don’t move because as soon as you do so you have blown your cover.  I now moved in even closer to get the whole head filling the frame.  The snake was obviously aware of my presence and the tongue started to taste the air but it did not move a muscle.  I was now about 2 inches away.  Click, I got the head.  Now I needed just one more image.  I moved the tripod so that I could place the camera directly above the snake and get a plan view.  That was it, I was satisfied and the snake was probably relieved to have an end to all those explosions of light flashing in front of it.  I packed everything up and took as small twig to lift the subjects head slightly off the ground.  It uncoiled and slipped slowly into the leaf litter at the side of the trail leaving the path clear and safe for anyone who might be walking on it later in the day.

Terciopelo

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 0.00 ins.  Total Weekly Rainfall 0.00 ins

Average Daily Rainfall 0.0 mm.  Total Weekly Rainfall 0.0 mm

Highest Daily Temp 96°F.  Lowest Daily Temp 74°F.

Highest Daily Temp 33.2°C.  Lowest Daily Temp 23.4°C.

Species List for the Week

Mammals

  • Central American Squirrel Monkey
  • Mantled Howler Monkey
  • Spider Monkey
  • White-faced Capuchin Monkey
  • Kinkajou
  • White-nosed Coati
  • Agouti
  • Pygmy Squirrel
  • Nine-banded Armadillo
  • Three-toed Sloth
  • Collared Peccary

Birds

  • Red-lored Amazon
  • Scarlet Macaw
  • Crested Guan
  • Great Curassow
  • Black Hawk
  • Yellow-headed Caracara
  • Spectacled Owl
  • Black-hooded Antshrike
  • Chestnut-backed Antbird
  • Short-billed Pigeon
  • White-tipped Dove
  • Magnificent Frigatebird
  • Brown Pelican
  • Plain Xenops
  • Rufus Piha
  • Long-billed Hermit
  • Red-capped Manakin
  • Chestnut-mandibled Toucan
  • Fiery-billed Aracari
  • Bright-rumped Atilla
  • Dusky-capped Flycatcher
  • Buff-rumped Warbler
  • Great Kiskadee
  • Bananaquit
  • Golden-hooded Tanager
  • Palm Tanager
  • Great Tinamou
  • Black Vulture
  • Turkey Vulture

Reptiles

  • Barred Ameiva
  • Cat-eyed Snake
  • Central American Smooth Gecko
  • Central American Whiptail
  • Common Basilisk
  • Four-lined Ameiva
  • Golfo Dulce Anolis
  • Mediterranean House Gecko
  • Terciopelo

Amphibians

  • Black and Green Poison Arrow Frog
  • Marine Toad
  • Red-eyed Green Tree Frog
  • Rough-skinned Dirt Frog
  • Savage’s Thin-fingered Frog

Butterflies

  • Anartia Fatima
  • Anartia jatrophae
  • Caligo eurilochus
  • Dione juno
  • Dryas iulia
  • Glutophrissa Drusilla
  • Heliconius erato
  • Heliconius hecale
  • Heliconius ismenius
  • Heliconius sapho
  • Heraclides cresphontes
  • Hermeuptychia hermes
  • Magneuptychia libye
  • Marpesia berania
  • Mechanitis polymnia
  • Morpho helenor
  • Morpho Menelaus
  • Opsiphanes tamarindi
  • Parides erithalion
  • Pierella helvina
  • Pierella luna
  • Philaethria dido
  • Phoebis sennae
  • Pygus oileus
  • Pyrisitia nise
  • Pyrrhogyra crameri
  • Siproeta stelenes
  • Urbanus simplicius

Plants

  • Alamandra  cathartica Flowering
  • Alpinia purpurata Flowering
  • Apeiba tibourbou Fruiting
  • Arachis pintoi Flowering
  • Arundina graminifolia Flowering
  • Attalea rostrata Fruiting
  • Bauhinia variegata Flowering
  • Brosimum utile Fruiting
  • Caryocar costaricense Flowering
  • Cascabella thevetia Flowering and Fruiting
  • Citrus spp  Fruiting
  • Clusia rosea Flowering and Fruiting
  • Clusia vallerii 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
  • 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
  • Inga spp Fruiting
  • Ixora coccinea Flowering
  • Lantana camara Flowering and Flowering
  • Lagerstroemia speciosa Fruiting
  • Morinda citrifolia Fruiting
  • Musa acuminate Flowering and Fruiting
  • Nephelium lappaceum Fruiting
  • Pachira quinata Flowering
  • 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
  • Zammia sp Flowering

 

 

Confused Cattleheart in Silver Trap   Leave a comment


Felipe del Bosque Blog August 13th 2012

Sun Shade

The rains have started to increase in frequency.  We have had several dry days but the rain comes in the evening and as it has done for several months now, in the form of violent thunderstorms.  We have early morning rain too, which seems to clear before the sun has risen too high in the sky.  As we approach the end of August visitor numbers to the lodge start to decrease but normally the rain increases.  By the time we get into September the downpours become heavier and heavier.  The creek, which almost completely dried up not so long ago, now has constantly running water.  Over the next month or so, depending upon the amount of precipitation the area receives, it will transform from babbling brook to raging torrent which will cascade over the waterfall on its way to the sea.  By the end of the week, the sun was shining, if not for all of the day, at least in the morning and a good way through the afternoon.

Laughing at Dinner

There was another Puma sighting this week and it occurred more or less in the same place as last week’s sighting, near the end of the Bosque driveway.  There were 3 people in a car on their way to surf early in the morning when they saw the cat so that made for a good start to the week.

This week the surf has been huge with massive waves making entrance to the swimming areas on the gulf beaches hazardous even for experienced surfers.  That has been the situation all the way up the Pacific coast of Costa Rica.

One night when I went down to the pond to see what was around, I found 4 Parrot Snakes, (Leptophis ahaetulla), all sleeping in different locations at the top of the vegetation.  Next day when I revisited the area I watched as a Laughing Falcon, (Herpetotheres cachinnans), flew off carrying one of the Parrot Snakes in its talons.  Laughing Falcons are specialized predators of snakes and over the years I have observed them feeding on a variety of different species.

Which Frog is Witch

The Bosque pond has been very active recently with an influx of Gladiator Frogs, (Hypsoboas rosenbergi).  There are generally 1 or 2 of these frogs present throughout the year but at the moment they seem to have arrived in large numbers.  Just after sundown you can hear their distinctive calls from some distance and over the past week there have been many pairs in amplexus.

The Smoky Jungle frogs, (Leptodactylus savegei), too have been breeding with several of their large foam nests being found not only around the pond but also in the drainage ditches.  Red-eyed Green Tree Frog, (Agalychnis callidryas), egg masses have been found in greater numbers this week hanging on the underside of leaves overhanging the pond.

The last remnants of what has been a bumper mango harvest this year are now left rotting under the trees on the ground in the orchard.  When you go out at night, fiery bright orange eyes can be seen reflecting from the fallen fruit and if you follow it in you will find yourself looking at the Black Witch Moths, (Ascalapha odorata), imbibing the fermenting fruit juices.  On one walk this week we saw a White Witch Moth, (Thysania agrippina), on the side of a tree remaining motionless and blending in perfectly with the pale background bark.

Bleeding Cattleheart

The butterfly numbers are down this time of year, but it only takes 1 or 2 days of sun and a slight increase in temperature to bring a few more individuals out of their torpor.  If you head off out while the sun is shining overhead there are still several species of longwings, sulphurs, peacocks, skippers, swallowtails and cattlehearts to be seen.

Around the upper garden near the Titi Trail there is always the good chance of bird sightings as there are a lot of large rotten trees full of holes which attract in woodpeckers, tanagers, toucans, aracaris, tityras, macaws, parrots and a number of birds of prey.  Also scattered around the gardened area are small patches of Lantana camara the glowing red and orange blooms of which are visited by a wide variety of butterfly species.  Along the forest edge around the periphery of the garden is also the favorite haunt of many butterflies.

It was while I was walking out of the garden, where the soaring temperatures and glaring light were proving to be a little overwhelming for me, that I found a Variable Cattleheart, (Parides erithalion), fluttering along the ride in a dappled shade more suitable for an Englishman abroad.  It flitted up and down, landing and then taking to the air again but not showing any intentions of settling.  I followed it for a short way until it alighted on a leaf, folded it wings closed and stopped to rest.  Approaching slowly and without any jerky movements I fixed in the viewfinder and managed to fire off a few shots.  The butterfly didn’t move and continued to remain motionless as I walk away to leave it in peace.

Parides erithalion

On one other occasion when the sun was shining brightly I headed off after lunch to walk a trail that I had not visited for some time, the path through the teak plantation.  In the past this has always been a lucrative hunting ground for a variety of species of all manner of animal life I don’t see anywhere else on the grounds.  All was quiet walking through the forest to the plantation.  As I exited from the wooded trail into the open area of the plantation, I was hit by an immediate increase in both temperature and light levels.  That change suited some of the butterflies though.

The Satyrs or browns are butterflies normally found in darker and damper conditions found under the canopy.  Their subtle brown coloration and habit of flying close to the forest floor make them difficult to see at times.  A common brown, the Confused Satyr, (Cissia confusa), seemed to be just that on this occasion, here it was resting on the path in full sun out in the open.  I slowly sank to my knees and then lay out flat on the muddy path while holding the camera in front of me and trying to focus on the beautiful creature I had in front of me.  I took one shot but as the flash went off it caused the now startled butterfly to return to the undergrowth.  The one shot was not a bad one though.

Cissia confusa

A little further on as I turned on to the main road running back towards the lodge, I was greeted by the sight of  several swallowtail butterflies flying in typical manner, fast and erratically along the forest edges bordering the road.  They are notoriously difficult to photograph as they never settle but today my luck was in.  One of them circled several times around the area I was standing then came to rest on a leaf at ground level and there it stayed, wings outspread displaying bright yellow horizontal bands which handsomely contrast with the jet black background.

Tropical Swallowtail Butterfly

The cattlehearts and swallowtails both belong to the family Papilionidae and the species are very difficult to separate one from the other in the field.  The cattlehearts larvae feed on Aristolochia vines which are poisonous.  The adults exhibit Mullerian mimicry whereby closely related species of poisonous butterflies are almost identical in markings and coloration.  The name Variable Cattleheart refers to the slight variations in markings within the one species making it even harder to identify on account of the fact it resembles a variety of other cattleheart Mullerian co-mimics.

The swallowtail offers the same degree of diagnostic difficulty; there are 2 species which are almost impossible to tell apart except for the diet of the larvae.  Heraclides cresphontes feeds on a wider range of host plants including citrus, Rutaceae and peppers.  Heraclides thoas, which as an adult is all but indistinguishable from the former, feeds only on peppers.

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

 A Flash of Hidden Silver

This is definitely the time of year for those arachnologists to visit.  At night there are Wandering Spiders all over the vegetation, their diamond starburst eyeshine revealing their whereabouts.  Along all of the trails, there are the giant webs of the impressive but harmless Golden Orb Spiders.  I have seen Crab-like Spiders and Spiny Spiders in webs close to the restaurant.  The latter 2 are very small and take some finding.  One other commonly seen spider is the Sliver Orb Spider, (Argiope argentata).  Its web is not as large as its yellow silk producing relative, the Golden Orb Spider, (Nephila clavipes), which also dwarfs it in body size.  Nonetheless the can be quite impressively sizeable.

Argiope argentata

As the name suggests they produce a web of a more commonly observed white color.  Whereas the web may not be immediately obvious because of its size or color, it is quite often easily found because of a large white cross, the stabilimentum, that the spider spins within the centre of the web possibly to mark its position so birds don’t fly through it, to attract in insects or for the spider to use as a cover behind which it can hide.  This spider had placed its web in the middle of a patch of lantana that was being visited by a host of nectar seeking butterfly species.  The gossamer trap must have been successful in providing food for the spider as was evidenced by several detached wing remnants floating on small pieces of silk not too far from its location.

Orb Weaver Spider

The next day on my walk through the teak plantation I found another spider but this time in a more clandestine location under a leaf.  As with the Silver Orb Spider I it was placed so that only the ventral side was visible.  Globally spiders are a very diverse group of animals and like so many other classes in an area of high diversity like Costa Rica, the reference material allowing you to identify your finds to species level is not always possible.  So for now this one will go into the file marked “Unidentified 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 Rainfall 0,4 ins.  Total Weekly Rainfall 2.79 ins

Average Daily Rainfall 10.1 mm.  Total Weekly Rainfall 70.9 mm

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

Highest Daily Temp 31.4°C.  Lowest Daily Temp 23.1°C.

Species List for the Week

Mammals

  • Howler Monkey
  • Spider Monkey
  • White-faced Monkey
  • Alfaro’s Pygmy Squirrel
  • Red-tailed Squirrel

Birds

  • Mealy Amazon
  • Red-lored Amazon
  • Scarlet Macaws
  • Great Curassow
  • Grey-necked Woodrail
  • Crested Caracara
  • Laughing Falcon
  • Roadside Hawk
  • Pale-billed Woodpecker
  • Chestnut-backed Antbird
  • Black-hooded Antshrike
  • Rufus Piha
  • Short-billed Pigeon
  • White-tipped Dove
  • Long-billed Hermit
  • Stripe-throated Hermit
  • Violet-crowned Woodnymph
  • Red-capped Manakin
  • Chestnut-mandibled Toucan
  • Grey-headed Tanager
  • Wedge-billed Woodcreeper
  • Golden-crowned Spadebill
  • Great Kiskadee
  • House Wren
  • Masked Tityra
  • Black-throated Trogon
  • Black Vulture
  • Turkey Vulture

Reptiles

  • 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
  • Averrhoa carambola Fruiting
  • Bauhinia variegata Flowering
  • Brassavola nodosa 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 speciosus 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
  • Miconia argentia Fruiting
  • Morinda citrifolia Fruiting
  • Musa acuminate Flowering andFruiting
  • Naucleopsis ulei Fruiting
  • Nephelium lappaceum Fruiting
  • Passiflora vitifolia Flowering
  • 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
  • Symphonia globulifera Fruiting
  • Terminalia catappa Flowering
  • Thunbergia grandiflora Flowering
  • Virola koschnyi Fruiting
  • Zammia sp Flowering

 

 

SLOWLY WRAPPED IN GOSSAMER THREADS   1 comment


Wildlife, nature, fauna and flora of Costa Rica.

Today was a little more typical of what we should be expecting weatherwise for September on the Osa Peninsula.  It started off raining, actually it continued raining from last night, it rained all day and it is still raining now.  It is not the heavy torrential rain that one associates with the 6 pm downpour, but rather that fine indistinct line between drizzle and mist with an intermittent heavier shower.

All of this makes for a very atmospheric feel to the forest and the grounds.  The trees are visible but appear almost phantom-like in a gloomy half light, obscured by mist.  It is as if you are looking at a picture with the color removed, a grayscale image.

The dingy conditions, though, did not deter some intrepid visitors who wanted to accompany me on the “Primary Forest Tour”.  The vegetation is always going to be there, so finding all things botanical to talk about is not a problem.  The dim, murky conditions, however atmospheric for us, seemed to dampen the enthusiasm of the animal life.  Mammals and birds are not easy to see in a rainforest under the most optimum of conditions.  Have you ever wondered why, when people come to the tropics to see tropical rainforest birds, birding guides don’t take them into the forest?  It is because vision is limited to about 15 feet in front of you.  Your view is hindered by lots of tree trunks, branches and leaves.  The irony about watching rainforest birds is that it is done in open areas where the trees have been cut down.  Now add to that a heavy mist and you don’t have conditions conducive to a lot of sightings.

Anteaters – Dimly Engaging

But you never know what will turn up and this morning as we wound our way along the muddy trail through the dank forest, bumbling along at its own pace coming from the opposite direction towards us was a Tamandua, otherwise known as the Collared Anteater, (Tamandua mexicana).  Now, although they are not rare, it is also not that common to see a Tamandua.  Along with armadillos and sloths, the anteaters constitute the mammalian order: Xenathra.  One trait, apparently shared by all the Xenathra is an ostensible lack of awareness for their immediate environment.  I have stood still in the forest and had sibling quads of Nine-banded Armadillos running back and forward over my feet without any fear, I doubt if they even knew I was there.  In the past I have walked alongside a Tamandua, that has remained oblivious to my presence until I accidently stepped on a dead twig, the snapping of which sent it unhurriedly up a tree, only for it to stop about 4 feet off the ground and lift its nose, smelling the air to see if I was still in the vicinity.  And so it was this morning, four people standing on the path and up it came, intent on its own business, searching for a meal of termites, (despite being called anteaters, they prefer a diet of termites), walked straight past us and on to wherever it may have been going.  This was a repeat performance of last night, when I had a Nine-banded Armadillo trundling along in front of me and displaying a complete lack of awareness as to my proximity.  In evolutionary terms I sometimes wonder how they made it this far along the line.

Rainforest animals. Rainforest mammals. Xenathra. Myrmecophagidae. Tamandua mexicana. Osa Peninsula.

Does the Tamandua, (Tamandua mexicana), know I am there

Slowly Wrapped In Gossamer Threads

If other wildlife is not compliant with your wishes to photograph it then look for spiders.  They come in all sorts of shapes and sizes, some that we consider a typical spider and others more weird and bizarre.  Spiders are the eighth most numerically named group of animals on the pl27anet.  You should also be able to find them irrespective of the weather conditions.  Spiders in webs make a good subject, especially if a breeze is not blowing.  If there is the mere breath of a zephyr it makes the task of focusing on a moving object close to the lens a little difficult, if not impossible.  Placed motionless in the center of a web is where an orb spider will normally sit unless disturbed.  That means, if you can avoid touching the web, you should be able to get pretty close.

Rainforest Spiders. Silk. Araneidae. Araneae. Argiope argentata

Silver-orb Spider, (Argiope argentata)

Orb spiders are some of the more evolutionary advanced of the arachnids.  Spiders are posed with two big problems, how to catch prey and how to consume it.  Several groups of arthropods have evolved the use of silk.  People think primarily of butterflies and moths, the caterpillars of which will use silk to make cocoons, (silk comes from Silk Moth caterpillars), or hold the chrysalis to a leaf or twig.  But nothing has perfected the use of silk to the imaginative and creative extent of the spiders.

Silk – Beautiful But Used to Deadly Affect

Silk is a protein.  It can be constructed from two forms of amino acid, a very loopy amino acid which can make it very elastic, or a crystalline amino acid which can make it very rigid.  In the silk glands of the spider, silk is a liquid, once the spider creates a silken thread, it becomes a solid.  Once silk is a solid, it stays a solid, the process cannot be reversed.  Silk is very elastic; it can be stretched to 300 times its own length before it snaps.  It can have the tensile quality half that of the finest steel.  Finally, if you were to take a strand of silk and let it float on a breeze, it would drift 50 miles before it broke under its own weight.  So, all in all, an absolutely amazing and versatile material.

Orb spiders have the ability to spin up to eight different kinds of silk.  To construct a web, the orb spider first spins a rigid silk which will form the framework.  It then moves from the centre to the outside attaching radial lines.  Now it moves in a circular fashion from the inside to the outside spinning a silk which when produced, absorbs water and becomes sticky.  The trap is now set.

Spiders. Webs. Araneidae. Araneae. Eriophora ravilla. Osa Peninsula.

Tropical Orb-weaver, (Eriophora ravilla)

If the web was taut, an insect the size of a large beetle hitting it at high speed would just be bounced off.  The fact that the silk is elastic allows the web to give, thereby removing all the kinetic energy from the impact, it then recoils and the prey is caught in the sticky silk.   That forceful contact will cause vibrations; the spider twangs the radial lines to locate the prey’s whereabouts, quickly goes down, wraps the unfortunate victim in silk and then delivers the poisonous bite.  The venom is a neurotoxin which will quickly quell the struggling of the now silken wrapped meal.  The food parcel is placed in a part of the web where the prey will be digested within the confines of its own skin by digestive enzymes injected at the same time as the venom.  When the prey is ready to be eaten, the spider, sticks in the chelicerae and sucks out the liquid soup.

Rainforest animals. Spiders. Orb-weavers. Araneidae. Araneae. Eriophora sp.

Beetles final moments in the embrace of a Tropical Orb-weaver, (Eriophora sp)

There are some animals though, that have evolved the means by which to escape their seemingly inevitable doomed entrapment.  Butterflies and moths are Lepidoptera, which means “Scaled wings”.  If you look at the wings of butterfly, you will find it is covered in tiny little powdery scales.  If you handle a butterfly you will find the scales come off in contact with your fingers.  If a butterfly or moth lands in a spider web, the scales shed from the wings allowing it to slide down over the web surface and away to freedom.  That is, if the spider is not too quick to detect where they are in the web, otherwise they will share the same ultimate fate as any other insect unlucky enough to have flown into that silken trap.

Golden-orb Spider. Webs. Spider venom. Araneidae. Araneae. Nephila clavipes

Ventral view of a Golden Orb-weaver, (Nephila clavipes), sucking the juices from a butterfly victim

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


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