Archive for the ‘Wandering Spider’ Tag

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.

 

The Trees Have Eyes   2 comments


Felipe del Bosque Blog August 5th 2013

title copy

Don’t Be Fooled

This week has been something of a mixed bag as far as the weather goes.  We are well into the wet season now and as might be expected it has been raining a lot.  The earlier part of the week was quite pleasant with clear skies, bright sunny days and star filled cloudless skies at night.  It seemed as if we had entered that period known locally as the veranillo or little summer.  At this time of year there is a two week period where the rain stops and it dries up.  It is nice time to visit the Pacific coast of Costa Rica as there are not so many visitors as in the main holiday periods, the weather is conducive to exploration and all the vegetation is lush and green.  If this was the veranillo then it was short-lived because the rain came back.  The latter part of the week has experienced the normal weather pattern for this time of year with days overcast and the rain starting early evening then continuing through the night into the early morning.   Those are perfect conditions for wildlife watching and photography, not too hot to go out and no bright contrasting shadows.

Further into the week the rain became more persistent.  Sometimes it rained all day but with no more than a gentle drizzle followed by more heavy precipitation overnight.  Each day is different.  Some days the sun shines, some it doesn’t but whatever the weather, this is a rainforest, everything is adapted to living in constantly rainy conditions and so at least some wildlife of one sort or another should be guaranteed.

The latter part of the week dispelled the notion that we might still be in the veranillo.  There have been some violent thunderstorms producing spectacular light shows in the sky accompanied with a moderate amount of rain.  The good news is that the creeks are running with a substantial flow rate now after a period of being very dry.

Caught In The Act

It has been another eventful week as far as animal sightings go.  On several separate occasions a Puma, (Puma concolor), and Ocelot, (Leopardus pardalis), have been recorded by the trail cameras that have been set up on the Titi Trail.  This is a trail running through secondary growth.  When the ground is wet, which it tends to be for 7 months of the year, you can see quite readily the tracks of any passing animals.  Most tracks are distinctive enough to allow identification of the creature leaving them.

One day tracks from huge male Puma were found on the approach to the suspension bridge.  The cat then appears to have walked over the bridge as the tracks were readily visible in the mud straight off the lodge side of the bridge and were heading in the direction of the restaurant.  The Spider Monkeys, (Ateles geoffroyi), were most certainly aware of the predators presence as they gave off their loud and distinctive alarm call for a long time.  The tracks then left the main trail and headed off through the forest to the lookout point over the Gulf.  Finally they turned and headed down the Creek Trail to the platform of the zip-line and disappeared into the forest.  We know that the female Puma is around so this may have been a transient male searching for a mate.

Puma Print

Bosque has recently started a project whereby the animals can be seen and photographed without anyone needing to be present.  We have set up 2 trail cameras near both the entrance and exit to the Titi Trail.  The cameras have been placed looking down the trail so that if anything is either walking towards or away from the camera we should get a good 30 seconds of footage.  The cameras are motion sensitive and detect infra red.  They use passive infra red LEDs to illuminate the subject without producing any visible light or flash.

Over the past month the cameras have produced some very good photos and video of what is around and also when it is around and what it is doing.  The surprising discovery is just how often the Collared Peccaries, (Tayassu tajacu), are walking the trails.  There seem to be large herds that come back and forth.  It would appear at first that they don’t have a large territory but it may well be there are several distinct herds and unless they are somehow marked in a fashion that would allow their identity to be easy verified then we shall just have to enjoy the sight of them walking by.

One of the cameras has a resident Agouti, (Dasyprocta punctata), that seems to come out and mark the trail every hour so we can expect to get to see an endless number of videos featuring that particular individual.  But he could be living a charmed existence.  We have viewed several videos featuring Ocelots, both day and night, and we know there is a female Puma in the area, she just hasn’t been captured on our cameras yet.  She has, however, featured in a cameo role on a trail camera put up not too far from our own by a young boy from England who was staying at the lodge last weekend.

There have been a number of other animals passing by in greater or lesser numbers: White-nosed Coatis, (Nassua narica), White-lipped Peccary, (Tayassu pecari), Tamanduas, (Tamandua mexicana), Nine-banded Armadillos, (Dasypus novemcinctus), Red-tailed Squirrels, (Sciurus granatensis), Tayras, (Eira barbara), Pacas, (Agouti paca), Common Opossum, (Didelphis marsupialis), Striped Hog-nosed Skunk, (Conepatus semistriatus),  Great  Curassow, (Crax rubra), Great Tinamou, (Tinamus major).  But let’s not forget that this is just the activity on the ground in the vicinity of the cameras, there is also a whole load of other activity going on up and above this level in the trees.

M2E38L130-130R407B315         M2E27L54-54R392B294         M2E28L68-68R393B303

M2E1L0-0R350B300         M2E45L47-47R350B300         M2E45L32-32R350B300

M2E45L32-32R350B300         M2E26L49-49R389B305         M2E1L0-0R350B300

Quadruple Vision

It doesn’t take long once the sun has set to go out and find a great many creatures that have been hiding during the day.  My nightly excursions to the pond this week have been rewarded with sightings of Northern Raccoons, (Procyon lotor), Common Opossums and Nine-banded Armadillos.  While looking at these nocturnal mammals your flashlight may catch the diamond sparkles being reflected from the grass, from the plants, from the tree trunks, everywhere in fact.  Follow the sparkles in and you will be amazed to find it is your light being reflected back at you from the eyes of spiders.  Not only might that revelation be somewhat astounding but also the size of the spiders themselves which may be tiny.  Depending upon the angle at which you catch it, the eyeshine may be silver, blue, green or orange but with the spiders always a sparkle.

Have a care though because not all of the spiders are tiny.  Once the sun sets below the horizon, emerging from safe daytime refuges come the Wandering Spiders, (Cupiennius spp) to set up their positions on the leaf tops or stems.  The Wandering Spiders don’t build webs, they are ambush predators.  They sit and wait.  The legs are covered  in hairs of differing types each of which performs a specific function.  There are tactile hairs which are stiff and are sensitive to touch.  A similar hair, the trichobothrium is super sensitive to the slightest touch as well as eddies in air currents.  There are chemosensory hairs that detect changes is the molecular environment around them.  There are slit-like structures called sensillae near the joints of the legs.  These detect vibration and mechanical movement of the substrate.

Cupiennius_sp

Even though the spider has eight eyes they are not necessarily used for hunting but all that other highly receptive sensory apparatus ensures the spider knows whether there is predator or prey close by.  If it is the latter then it is generally goodbye.  I have seen the Wandering Spiders jump and take moths from the air, I have seen then jump on any small passing invertebrate and I have even seen then eating the Red-eyed Green Tree Frogs, (Agalychnis callidryas), at the pond.

Wandering Spiders are not dangerous, they will not kill you but they will give a nasty little ulcerated bite.  And they can jump so don’t get too close.  But if you leave them alone they won’t bother you.

Small Head and bulging Red Eyes.

The rains always bring out the frogs.  June, July and August is the best time to see frogs at Bosque as it is the main breeding season for many of the species to be found on the grounds.  Year by year there is a flux not only in the species to be found but also in the numbers of those species.  The Red-eyed Green Tree Frogs are present all year, every year but in much greater numbers in the wet season when their distinctive “chuck chuck” calls can be heard everywhere around the pond.  Their egg masses can be seen throughout the year too hanging as they do from the underside of leaves overhanging the water where the diligent female has placed them.

Over the past week there have been male Red-eyed Green Tree Frogs calling from every level of vegetation immediately next to or in the close vicinity of the pond.  The males set up their territories once the sun has set and then call to attract a mate.  The female which is much bigger than the male selects a partner for the evening depending on the quality of his call, the deeper the better.  The frogs pair up and visit the pond about 3 times over the course of the evening.  Each time the female absorbs a lot of water through her skin, fills her bladder and then they amplected couple make their way to a leaf overhanging the water.  The female lays a group of about fifty eggs which the male sitting on her back fertilizes as she expels them.

Agalychnis_callidryas

The eggs hang over the water for about a week until the tadpoles have developed enough to wriggle free and drop into the water where they have to complete the aquatic stage before metamorphose into froglets which leave the water and disappear into the vegetation before emerging some time later as adults.

The Small-headed Frog, (Dendropsophus microcephala), on the other hand may or may not be present each year.  Sometimes there are just one or two calling over the course of a season, last year there were none.  This year on the other hand they have arrived in huge numbers.  I was never sure in the years gone by whether they were being outcompeted by the more commonly seen and heard Banana Frog, (Dendropsophus ebraccatus), which are always here in reasonably large numbers.  This year though they haven’t appeared in such profusion as in years past.  I think it is time to start the frog counts again.

Dendropsophus_microcephalus

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 

Try Again

Several months ago there was a White-necked Jacobin Hummingbird, (Florisuga mellivora), that had nested right by the path on the Zapatero Trail.  The nest contained 2 eggs but one day both the eggs had disappeared and despite the fact the nest was intact the female was nowhere to be seen.  Then, a couple of weeks ago on a different part of the Zapatero Trail, there appeared another nest looking exactly the same and of the same species.  Although the two nest sites seemed somewhat removed, when looking at the map, the trail curves round at 180º so the second nest in actual fact lay very close to but just uphill of the first.  My guess would be that it is the same female.  She might have chosen a different location but not too far away based on the failure of the prior brood.

Florisuga_mellivora

Every day as I walked the Zapatero Trail the female White-necked Jacobin would sit tight until I approached to passing.  She would then take off and wait for me to go further down the trail before returning to the nest.  As the chick grew progressively larger the female would spend less time on the nest.  The chick now filled the nest and one day as I got closer I could see the nest was empty so I hope on this occasion the chick had managed to take to the air and fly off.

Florisuga_mellivora

There is a low success rate for breeding birds.  The forest is full of predators and parasites.  Certainly around the lodge if there is a nest containing either eggs or chicks it doesn’t take long for an individual of the species Tropical Bird-eating Snake, (Pseustes poecilonotus), to pay visit.  These snakes can reach well over 6 feet in length so can eat birds of most sizes here.  Quite often the birds have to raise 2 or 3 clutches a year to have 1 successful set of fledglings.

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 0.67 ins.  Total Weekly Rainfall 4.70 ins

Average Daily Rainfall 16.8 mm.  Total Weekly Rainfall 117.9 mm

Highest Daily Temp 84°F.  Lowest Daily Temp 74°F.

Highest Daily Temp 28.8°C.  Lowest Daily Temp 23.3°C.

Species List for the Week

Mammals

  • Mantled Howler Monkey
  • Spider Monkey
  • White-faced Capuchin Monkey
  • Nine-banded Armadillo
  • Common Opossum
  • Common Tent-making Bat
  • Western Red Bat
  • Northern Raccoon
  • White-nosed Coati
  • Agouti
  • Red-tailed Squirrel
  • Collared Peccary

Birds

  • Mealy Amazon
  • Orange-chinned Parakeet
  • Red-lored Amazon
  • Scarlet Macaw
  • Great Curassow
  • Laughing Falcon
  • Pale-billed Woodpecker
  • Black-hooded Antshrike
  • Chestnut-backed Antbird
  • Short-billed Pigeon
  • Red-capped Manakin
  • Chestnut-mandibled Toucan
  • Golden-crowned Spadebill
  • Great Tinamou
  • Little Tinamou
  • Black-throated Trogon
  • Black Vulture
  • Turkey Vulture

Reptiles

  • Barred Ameiva
  • Cat-eyed Snake
  • Central American Smooth Gecko
  • Central American Whiptail
  • Common Anolis
  • Common Basilisk
  • Clawless Gecko
  • Four-lined Ameiva
  • Golfo Dulce Anolis
  • Green Iguana
  • Litter Skink
  • Mediterranean House Gecko

Amphibians

  • Banana Frog
  • Black and Green Poison Arrow Frog
  • Fitzinger’s Rain Frog
  • Golfo Dulce Poison Arrow Frog
  • Marine Toad
  • Milky Frog
  • Parachuting Red-eyed Green Tree Frog
  • Red-eyed Green Tree Frog
  • Rough-skinned Dirt Frog
  • Savage’s Thin-fingered Frog
  • Small-headed Frog
  • Tink Frog

Butterflies 

  • Anartia Fatima
  • Anartia jatrophae
  • Colobura dirce
  • Dryas iulia
  • Heliconius erato
  • Heliconius ismenius
  • Heliconius sapho
  • Hermeuptychia hermes
  • Mesosemia zonalis
  • Morpho cypris
  • Morpho menelaus
  • Philaethria dido
  • Phoebis sennae
  • Pierella luna

Plants

  • Alamandra  cathartica Flowering
  • Alpinia purpurata Flowering
  • Apeiba tibourbou Fruiting
  • Arachis pintoi Flowering
  • Arundina graminifolia Flowering
  • Attalea rostrata Fruiting
  • Bauhinia variegata Flowering
  • Cascabella thevetia Flowering and Fruiting
  • Citrus spp  Fruiting
  • Clusia vallerii Fruiting
  • Cocos nucifera Flowering and Fruiting
  • Crestentia alata flowering and Fruiting
  • Costus speciosus Flowering
  • Dypsis lutescens Flowering and Fruiting
  • Etlingera elatior Flowering
  • 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
  • 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
  • Stachytarpheta frantzii Flowering
  • Zammia sp Flowering

 

 

Here We Go Again   4 comments


Felipe del Bosque Blog November 12th 2012

Sun Shade

I made an earlier than normal return to Bosque this year.  The wet season had seen its share of rain but now the heavy showers are interspersed with long periods of blue sky and bright sun.  Mammal, bird, reptile, amphibian and butterfly sightings are good.

I keep a daily nature diary of animals and plants, (flowering and fruiting), that I have seen at the lodge.  At the end of the week the lists are added to the bottom of this blog which allows people to see what is going on in advance of their visit to Bosque or to keep in touch when they have left.  Anyone reading but not visiting can gauge the amount of activity taking place in the natural world down on the tip of the Osa Peninsula, Costa Rica.

This year I have decided to add something extra, something a little different.  Birders have their “Big Year” so I thought it might be nice to have a big year but not limiting myself to the avifauna, but rather everything.  It won’t take much more effort over and above what I already record and catalogue.  It is not competitive either, just a bit of fun.  It will enable me to post a weekly update of cumulative numbers across the board of species inventories.  The readers will then be able to see at a glance the amount of fauna and flora that can be experienced and over what period of time at Bosque.

The records will be confined to the 800 acres that constitute the grounds of Bosque del Cabo and will be based on casual observations.  Hopefully I should get some photos to post too.

Doing the Rounds

Around the grounds there are the usual mammal sightings with Agoutis, (Dasyprocta punctata), White-nosed Coatis, (Nasua narica), and Red-tailed Squirrels, (Sciurus granatensis), in the gardened areas in front of the restaurant.  Spider Monkeys, (Ateles geoffroyi), Howler Monkeys, (Allouata palliata), and White-faced Monkeys, (Cebus capucinus), can be seen just about everywhere around the grounds.  The White-faced Monkeys have been up to their usual nasty tricks.  One couple out in the garden was trying to photograph a Chestnut-mandibled Toucan, (Ramphastos swainsoni), when a White-faced Monkey grabbed and dispatched the unfortunate bird.  It wasn’t the photograph they were looking for but it makes for a talking point back home.

One night, just before dinner, a Kinkajou, (Poto flavus), came into the bar, which was full of guests at the time, and made its way up one of the support poles into the roof and disappeared from view.  Kinkajous are not uncommon around the grounds of Bosque and can quite often be heard up in the tree tops at night but this was the first sighting in the bar.

Summer Calling

The Scarlet Macaws can be seen in the morning flying east to the Golfo Dulce beaches where they take up their daily occupancy of the almond trees, the nuts forming a staple part of their diet.  Later in the afternoon they can be flying this time west returning to roost for the evening.  Their strict adherence to a timetable allows guests to position their cameras to frame the sea and the sky then just wait for the macaws to fly by and fill the foreground space between.

I thought I might make it back before the migrant birds returned but they got here before me.  The very distinctive call of the Summer Tanger, (Pingara rubra) can be heard from the vegetation all around the lodge and will continue to be so for the next few months.  The Dusky-capped Flycatcher, (Myriarchus tubiculifer), is another bird with a soft yet unmistakable call which is being heard all around the restaurant area and mango orchard at the minute.

Prior to their visit, bird calls are something that a visitor to the tropics should acquaint themselves with as not only will they allow you to hear what is around, but also where it is which is essential if you want to spot them.  Looking for birds within the depth of the forest is a somewhat difficult task due to the obstructive presence of so much vegetation.  The open areas, gardens and forest edges are your best bet for seeing much of the bird life.

At the moment within the darker confines of the forest beneath the canopy the Red-capped Manakin, (Pipra mentalis), and the Blue-crowned Manakin, (Pipra coronata), are calling as well as the Rufus Piha the call of which sounds like someone giving a wolf whistle.

In front of the restaurant the Roadside Hawk ,(Buteo magnirostris), Crested Caracaras, (Caracara cheriway), and Yellow-headed Caracaras, (Milvago chimachima), are a daily sight along with the ever present Black Vultures and Turkey Vultures.

Spotted Frogs

Agalychnis callidryas

Despite the fact that it is still wet, the Tink Frogs, (Diasporus diastema), have now all but stopped calling.  Down by the pond the Red-eyed Green Tree Frogs, (Agalychnis callidryas), are still present along with the Marine Toads, (Rhinella marinus) and Savage’s Thin-fingered Frog, (Leptodactylus savegei).  There are one or two Banana Frogs, (Dendropsophus ebrecattus), sitting on the Water Hyacinths, (Eichhornia crassipes), and the occasional call of a Parachuting Red-eyed Green Tree Frog, (Agalychnis spurelli), can be heard.  The Gladiator Frogs, (Hypsoboas rosenbergi), that were out in profusion a few months ago have disappeared.  There have been one or two Masked Smiliscas, (Smilisca phaeota), calling too and as the sun sets you can hear the distinctive “Chuck” of Fitzinger’s Rain Frog, (Craugastor fitzingeri).

Leptodactylus savagei

The Red-eyed Green Tree Frogs are still spawning and their eggs can be found in distinctive gelatinous clusters hanging beneath the leaves overhanging the pond which make an easily available food source for the Cat-eyed Snakes, (Leptodeira septentrionalis).  Once the sun sets out come the snakes.  They make their way over the surface of the pond and over the vegetation behind, tongues flicking in and out in search of that protein packed jelly.  One night I found a Terciopelo sitting above head height on a leaf behind the pond.  The occasional sleeping Basilisk, (Basaliscus basaliscus), may also be encountered but they are easily disturbed.  You make get a shot but it doesn’t take much to cause them to fall to the ground and run for cover.  While out at night you cannot fail to see, especially if looking for eyeshine, the tell tale diamond sparkle coming from the eyes of Wandering Spiders, (Cupiennius sp) sitting on top of the leaves.  One night I had fun taking some pictures of a tiny katydid down by the Bosque pond.  I have no idea what species it is but it was quite photogenic.

Agalychnis callidryas eggs

Fitzinger's Rain Frog

Smilisca phaeota

Wandering Spider

Unidentified Katydid

Only When The Sun Shines

As the weather is reasonably dry and bright, at least on some days, the butterflies take to the wing.  There are neither a huge number of species nor many individuals of each species to be seen this time of year. If you do go for a walk on a sunny day you should get to see some of the more brightly colored species around the grounds, particularly at the Lantana bush where several species of Longwings will be flitting from flower to flower in search of nectar. The earlier you go the better it is to get the photographs before they are fully warmed up and less likely to settle for any great period of time.

Dryas iulia         Heliconius ismenius         Heliconius erato

The same applies to the pond and the dragonflies.  There are very few species around at the moment.  But if you watch them, observing where they land, then you can set up your camera and wait.  With a little patience you should get a fairly good chance of a close-up shot.

Micrathyria ocellata         Micrathyria ocellata        

Fruitless Search

The end of the wet season is not the best time to find either flowers or fruit.  The rain will have ensured that the forests have a deep verdant green aspect to them.  But as we move into that transitional period from wet to dry, many of the plants are stimulated into bearing flowers.  By the time we get into December and January there will be a greater, sometimes subtle and at other times garish, display of color throughout the forest.  For now though you just have to enjoy the deep greens.  If you thought green was green you were very much mistaken.  Find a vantage point and look out over the forest.  You will see emerald, jade, olives, lime, bottle green, sea greens, pea green in fact green in every shade and hue you could imagine.

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 Small Problem

One of the most compelling sites of the rainforest is ubiquitous presence of the industrious Leaf-cutter Ants, (Atta sp) which seemingly never rest.  When they are not active their trails can be seen as clear cut paths that run through lawns and across the forest floor.  When they are active, the trails resemble rivers of green moving leaf fragments, which the majority of the workers heading back towards the nest are carrying in their mandibles above their bodies.

Atta cephalotes         Atta cephalotes         Atta cephalotes

Once the leaf is taken into the nest it is dropped and then the work of another caste begins.  It chops the leaf into smaller fragments.  Descending down into the depths of the nest the workers get smaller and smaller progressively cutting the leaf into ever finer fragments which by the time they reach the nest gardens are processed into a grey chewed up mulch.  The ants defecate on this which adds amino acids and enzymes.  This is now the compost on which they grow a very specific fungus that ultimately provides food and sustenance for all the ants in the colony, (upto 8 million of which exist in a mature colony).

Atta cephalotes

This last week there has been a tremendous amount of leaf-cutter activity on all of the Bosque trails and also by my cabin.  Here was a perfect opportunity to try and get some pictures.  This is never an easy task.   You have to get the camera in a position where you can see the ants passing through a plane of view.  Due to the close proximity of the lens to the subject when an ant does pass by it does so very quickly so the shutter speed has to be high.  The distance from the lens means you have a shallow field of view, so to increase your chances of getting one or two in the right plane; you have to close the aperture right down.  A fast shutter speed and a minute aperture allow very little natural light to enter so you have to provide a lot of light by way of flash.  I use 5 separate flash units.  Even then, the chances of getting one at the right exposure filing the frame are slim, most of the ants are entering or exiting the frame or are too far away or are too close.  But due to the number of them all moving in the same direction, then you should get one or two keepers, it depends on how much time and patience you have.

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 0.23 ins.  Total Weekly Rainfall 1.63 ins

Average Daily Rainfall 5.9 mm.  Total Weekly Rainfall 41.4 mm

Highest Daily Temp 91°F.  Lowest Daily Temp 75°F.

Highest Daily Temp 32.5°C.  Lowest Daily Temp 23.9°C.

Species List for the Week

Mammals

  • Howler Monkey
  • Spider Monkey
  • White-faced Monkey
  • Nine-banded Armadillo
  • White-nosed Coati
  • Agouti
  • Red-tailed Squirrel
  • Vesper Rat

Birds

  • Mealy Amazon
  • Red-lored Amazon
  • Scarlet Macaws
  • Great Curassow
  • Crested Caracara
  • Laughing Falcon
  • Roadside Hawk
  • Yellow-headed Caracara
  • Pale-billed Woodpecker
  • Belted Kingfisher
  • Dusky-capped Flycatcher
  • Chestnut-backed Antbird
  • Black-hooded Antshrike
  • Rufus Piha
  • Short-billed Pigeon
  • White-tipped Dove
  • Rufus-tailed Hummingbird
  • Stripe-throated Hermit
  • Blue-crowned Manakin
  • Red-capped Manakin
  • Chestnut-mandibled Toucan
  • Grey-headed Tanager
  • Summer Tanager
  • Tawney-winged Woodcreeper
  • Golden-crowned Spadebill
  • Great Kiskadee
  • Black Vulture
  • Turkey Vulture

Reptiles

  • Cat-eyed Snake
  • Clawless Gecko
  • Common Basilisk
  • Four-lined Ameiva
  • Golfo Dulce Anolis
  • Green Iguana
  • Litter Skink
  • Terciopelo

 Amphibians

  • Banana Frog
  • Black and Green Poison Arrow Frog
  • Fitzinger’s Rain Frog
  • Marine Toad
  • Masked Smilisca
  • Parachuting Red-eyed Green Tree Frog
  • Red-eyed Green Tree Frog
  • Smoky Jungle Frog
  • Stejneger’s Dirt Frog

Butterflies

  • Anartia Fatima
  • Anartia jatrophae
  • Dryas iulia
  • Eurybia lycisca
  • Glutophrissa Drusilla
  • Heliconius erato
  • Heliconius hecale
  • Heliconius ismenius
  • Heliconius sapho
  • Hermeuptychia hermes
  • Heraclides cresphontes
  • Magneuptychia libye
  • Morpho helenor
  • Morpho Menelaus
  • Opsiphanes tamarindi
  • Pareuptychia ocirrhoe
  • Philaethria dido
  • Pierella helvina
  • Pierella luna
  • Pyrgus oileus
  • Pyrrhogyra crameri
  • Taygetis Andromeda
  • Urbanus simplicius

 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 Flowering andFruiting
  • Clusia vallerii Flowering and Fruiting
  • Cocos nucifera Flowering andFruiting
  • Crestentia alata flowering and Fruiting
  • Costus speciosus Flowering
  • Couroupita guianensis 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
  • Lantana camara Flowering andFlowering
  • Lagerstroemia speciosa Fruiting
  • Morinda citrifolia 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
  • Psychotria sp Fruiting
  • Stachytarpheta frantzii Flowering
  • Thunbergia grandiflora Flowering
  • Virola guatemalena Fruiting
  • Virola sebifera Fruiting
  • Zammia sp Flowering

Wandering Spiders: Nocturnal Predators of The Rain Forest   2 comments


Today I saw for the first time a Long-tailed Woodcreeper, (Deconychura longicauda).  It is not a common bird in the South Pacific region of Costa Rica, and that goes for a lot of the fauna and flora of Costa Rica.  In terms of biodiversity, there tend to be a lot of species but not many individuals of any one species.  There is a saying, “Common trees are rare, rare trees are common” which can be applied across the taxonomic board.  Nonetheless for a biologist out in the field every day, which is where I have spent the majority of my working life, it is still a thrill to see something new.  And to that effect, I am, therefore, thrilled on an almost daily basis; there is always something new to see.

First time visitors to the tropics will be captivated by many new sightings, almost everything will be a first time experience, plants and animals only ever seen in books or on T.V.  For a resident in these forests though, the daily viewing of monkeys, coatis, agoutis, macaws, and toucans can sometimes render you complacent of their presence.  It is not until something like a Long-tailed Woodcreeper appears that makes me once again contemplate the marvel of it all, nature, its diversity and all the complex interactions that exist within the ecosystem.  Take any one element out of the system and, although it may not be obvious, the system will be diminished.

Along with the woodcreeper, this week I have seen for the first time Turquoise Cotingas, (Cotinga ridgwayi) and White-lined Tanagers, (Tachyphonus rufus).  For only the fourth time in ten years, I saw the Eyelash Viper, (Bothriechis schlegelii).  But, my main interest is with the butterflies.  I have been fascinated by butterflies since the age of three.  I don’t know what it was that ever first captivated me, but whatever it was has had a very strong hold on both my imagination and natural curiosity.

On the Osa Peninsula, over a twenty year period I have inventoried 400 species of butterfly, all at ground level.  Most butterflies live at the level of the tree tops, so imagine how many more species I could add to that list if I could monitor in the canopy.  The species inventory for the nearby Corcovado National Park is 220 species.  Once in a while I will get one, two or perhaps three new species turn up in a week.  That puts a spring in my step and a smile on my face.  It amuses me when I am leading a guided tour through the forest and I stop everyone in their tracks, then move slowly towards something that has caught my eye.  The onlookers, paused with baited breath wait for me to signal for them to come forward and see the elusive and hidden form of some large cat, only to be shown a small, almost imperceptible, but never before seen by me,  species of skipper or hairstreak.  Each to their own, but that sighting will certainly have made my day.

Wandering Around At Night With Spiders

Wandering spiders, (Cupiennius spp), are nocturnal spiders.  As darkness descends, they emerge from their daytime hiding places and set up their position for the night.  They prefer plants with broader leaves and some form of cavity, perhaps a hollow stem, which they use as a daytime refuge away from the drying sun and wind.  They do not build webs, they are ambush predators.  The Wandering Spiders are finely tuned killing machines; they have vibration detectors and sensitive hairs on the legs that alert them to the presence of prey in their vicinity, any cockroach or cricket that may pass by.  The vibration detectors sense the movement of its prey on the leaf surface.  The hairs on the legs are very sensitive to minuscule eddies in air currents close to the spider.  The unfortunate insect is unaware of the imminent danger, the spider remaining motionless until the last moment. The spider’s leg borne sensory apparatus give it precise information about the insect’s proximity.  When the prey comes within range, the spider moves with lightning quick speed, it pounces forward and grabs the prey with its front two legs which hold the unfortunate victim in a vice-like grip while it sinks its fangs, chelicerae, into the hapless individual.

Veridion-Adventures Wandering-Spider Cupiennius-coccineus Nature Photography Travel Adventure Holidays

Wandering Spider, (Cupiennius coccinea)

After envenomation, the prey is held at legs length away from the spider to prevent it retaliating with a bite or sting of its own against its assailant.  It is held above the leaf surface so that it has nothing to struggle against in an attempt to wrest itself free.  The whole attack takes less than 0.2 seconds.  The venom works quickly on the prey’s nervous system, paralysing it into a state of immobility and finally death.  In terms of energy expenditure, venom is very expensive for the spider to produce and generally nature does not waste energy.  If the prey is small enough and poses no threat to the spider, then it will simply be overpowered and killed without the spider resorting to its precious venom supplies in order to subdue it.

Veridion-Adventures Wandering-Spider Cupiennius-coccinea Natue Photography Travel Adventure Holidays

Wandering Spider, (Cupiennius coccinea). Close up of head

Spiders do not have mouth parts capable of chewing, so digestive juices are pumped into the prey converting the insect’s tissue within its shell-like exoskeleton into a soup which the spider eventually proceeds to suck out. Some of the larger wandering spiders will feed on the smaller frogs  and have even been seen jumping on and biting snakes.  They also have the unnerving ability to jump and snatch flying moths straight out of the air.  There are no spiders or scorpions in Costa Rica capable of killing you, although wandering spiders can inflict a nasty bite which will result in a localised ulceration.  But if you keep you distance you can watch these intriguing creatures going about their business almost everywhere at night.

http://www.veridionadventures.co.uk

 

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