In The Heat of The Night   Leave a comment


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

It has now been over a month since the unusually heavy rains ceased falling.  During the intervening period of time there has been barely a drop of water and the rain that has fallen conveniently fell overnight.  How quickly the ground has dried though.  The places on the trails where some of the run off was flowing has now stopped completely.  Most the trails have hardened and become firm under foot once again.  The temperatures too have started to creep up and up with midday temperatures hitting the 100⁰ F, (40⁰ C), mark.  At night the sky is clear and bright.  With no cloud cover the temperatures go back down again hitting a pre-dawn low of around 71⁰ F, (22⁰ C).

This is the season when we start to see the trees producing flowers.  Several trees have already started blooming as have some of the orchids.  In the gardens the flowers attract insects, more notably the butterflies.  As you walk down the forest trails, gaps in the canopy allow light to penetrate to the forest floor and these open sunny glades seem to be favored by both dragonflies and damselflies.  Birds are actively seeking out nesting sites.  So, there is no shortage of subjects to photograph as you leisurely wind your way around the grounds.

Night of the Pale Parasols

Sometimes a structure will appear as if overnight that will then catch the observant eye.  They don’t have to be large structures but there will be something about them that make them stand out.  At the side of the road on a bank where the drive had been cut through a hill and only about 4 feet from the ground I noticed a pale umbrella topped cone suspended from an exposed tree root.  Beneath the fibrous parasol the cone was a squat in dimensions but covered with long pale yellow bodies.  Closer examination revealed that each body had a thorax, wings, legs and a head.   I was looking at wasps, more particularly the aptly named Parasol Wasps, (Apoica pallens).

Parasol Wasp. Hymenoptera. Vesperidae.

Parasol Wasp Nest, (Apoica pallens)

The genus Apoica contains but six species.  Strangely for wasps the parasol wasps are nocturnal.  The nest consists of a swarm of workers with several queens and males.  They are active at night engaged in hunting and nest building.  Should you be near one of the nests after sunset and using a flashlight they will readily be attracted to its beam.  During the day the wasps line up, pressed close together and cover the nest but will have no hesitation taking to the air to vigorously defend it should you venture too close.

A Hole Full of Horror

Once the sun has set then the nocturnal creatures that have been hidden away in nooks and crannies by day start to emerge.  Over the past week or two, about half an hour after sundown a juvenile tarantula has been crawling from its web-lined lair hidden in a crack in tree trunk.  Tentatively at first its front legs ease into the open.  Once it is sure the area is safe it slowly creeps into the open and sits head down not too far from its safe refuge and waits for a meal to come by.  Tarantulas do not build webs, they are ambush predators.  They sit and wait for prey to come to them rather than actively hunt food.  A slight tap of the foot on the tree root and this hairy arachnid behemoth quickly returns to the dark recesses of its den.

Tarantula. Osa Peninsula. Felipe del Bosque

Juvenile Tarantula. Unidentified Species.

Tarantulas have a reputation they don’t deserve.  It is unlikely that anyone has died from an American tarantula bite.  The thought of being bitten by a large, hairy spider is what most likely unnerves most people.  Whereas a tarantula bite is relatively harmless for humans, the neurotoxic venom that is injected will subdue and kill insects reasonably quickly.  The female tarantulas are larger in body size and live longer than the males.  A female tarantula can live anything up to 25 years.  On one occasion last week I saw this juvenile catch and eat a long-horned beetle that had ventured too close.  Tarantulas mash the prey with the chelicerae and suck out the juices.

Therasophidae. Mygalomorphidae

Tarantula. Unidentified Species.

It is never a good idea to get too close to a tarantula in case it becomes threatened.  The bite might not pose a problem for a human but the tarantulas have another means of defense.  Using the legs they flick barbed urticating hairs from the body which can become lodged in a potential predators eyes or upper respiratory tract causing severe distress.

Tarantula.

Tarantula. Unidentified Species.

The tarantulas belong to the spider suborder: Mygalomorphae.  They are a rather older evolutionary group of spiders and can be characterized by the chelicerae, (fangs), facing directly down.  Most of the world’s 903 species of tarantula live in the tropics and form the family: Theraphosidae.  The name tarantula is something of a misnomer as they were named after the European tarantulas which belong to the family: Lycosidae or Wolf Spiders, the bites of which supposedly, (again without any basis in fact), would cause people to go into wild convulsions.

Therasophidae

Tarantula. Unidentified Species.

Unravelling the Thread of Death.

There has been one other nocturnal hunter that I have seen over recent weeks that I don’t normally find with a great deal of regularity, the Brown Blunt-headed Tree Snake, (Imantodes cenchoa).  These long, slender serpents become active as the sun sets.  The body is very thin with the neck drawn out into a super narrow section.  Supported at the end is a short head bearing large bulbous eyes.  The body is triangular in section with a light tan base color interrupted along its length by large dark brown saddle markings.

The presence of this snake spells instant doom for small sleeping lizards that may have taken refuge in a “safe” zone at the tip of a leaf.  Normally the amplified movements of a predator along the length of a leaf would immediately alert the lizard to imminent danger allowing it to jump to safety and flee into the undergrowth.

Brown Blunt-headed Tree Snake

Brown Blunt-headed Tree Snake, (Imantodes cenchoa)

Not so with the Brown Blunt-headed master of stealth.  Its light weight and slender form permit movement without disturbance.  The eyes and tongue search for signs of a meal.  The triangular body section give rigidity enabling the prowling snake to reach out into the darkness and snatch the sleeping victim from its secure perch.

The adults can reach several feet in length.  Over the past week I have found and an adult and a juvenile.  The photo is of the juvenile which I found on several separate occasions at different locations around the pond.

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

 

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