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

 

 

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5 responses to “Hidden In The Full Light Of The Sun

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  1. Enjoyed reading about the spiders, even if they probably would terrify me in real life.

  2. loved seeing the snake photo again (at home this time) but not quite as much as finding it on the path – made my day!!!!! cheers Philip

  3. Real interesting post Philip. That spider find was great. And, I still can’t believe how close you insist on getting to those terciopelos. Makes me feel like a bit of coward for keeping my 6 foot distance and using the 300mm lens…

  4. Very nice blog, Philip! Could your Argiope argentata also be Argiope savignyi??

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