Archive for the ‘Tarantula Hawk’ Tag

A Gruesome End   2 comments


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

Life as Normal

The weather pattern has now been set for the next three or four months.  The sun shines during the day and the rain comes down at night.  At least that has been the situation over the past week and if records from previous years tell us anything then that it how things should more or less remain until September.

Life continues here irrespective of the weather conditions.  One question I am asked a lot is “What do the animals do when it is raining?”  The animal life here is adapted to living in a rain forest so what happens is that everything continues as normal.

At the moment there are large groups of White-nosed Coatis, (Nasua narica), around the grounds.  The coatis are related to raccoons and like their cousins will feed on just about anything they find whether it be grubs and land crabs that they dig out of the ground, eggs and chicks stolen from birds’ nests or simply the abundance of fruit that has fallen to the ground.  The males are solitary and I found this one engrossed in a feeding frenzy with the jack fruits that were littering the ground beneath the tree that had produced them.  He was so preoccupied with the sweet treat that my presence was of no concern.

Nasua narica Carnivora Procyonidae

White-nosed Coati, (Nasua narica)

The females are gregarious and can be found in large groups which consist of the adult females and young of varying ages.  They are a little more wary than the males and if approached will run for the cover of dense vegetation.  This week some visitors to the lodge were greeted in the early morning by White-faced Monkeys, (Cebus capuchinus), in the tree over the cabin and a large group of White-nosed Coatis on the lawn in front.  All of a sudden the monkeys went berserk, barking a frantic alarm call.  The coatis bolted for the forest. That was a bad mistake as a few moments later a female Puma, (Puma concolor), emerged carrying one of the baby coatis in her mouth.  The guests experienced mixed emotions of being both sad and thrilled at the same time.

A few weeks ago I had a fledgling male Black-throated Trogon, (Trogon rufus), land beside me as I walked through the forest.  This time it was the turn of a female.  The females are not as vividly colored as the males.  The back is a soft brown and the belly is a pale yellow although it still has the eye ring and the black and white barred tail.

Trogon rufus. Trogonidae

Black-throated Trogon, (Trogon rufus) Female

Eaten Alive

Over many years of having lived in the area there are creatures that I have seen but have never been fortunate to take a photograph of.  It may well have been that I was not carrying the camera or that the sighting was too fleeting or that the subject would not stay in one spot long enough.  For whatever the reason the result was the same, a feeling of frustration.

One such insect that had evaded me for so long was one of the most predatory hymenopterans with a gruesome life history, the Tarantula Hawk.  These are impressively large wasps and one you most certainly not want to be stung by.  The female is the predator and she is constantly on the move in search of prey for her offspring, the living flesh of a spider.  As I am walking around, I have encountered over the years, individuals that land, with the antennae and wings in constant motion.  She alights and then takes flight almost immediately giving no chance of taking a photograph.  They are distinctive in size and tend to be bluey/black in color with bright orange wings.  This one also had orange antennae.

Pepsis aquila. Hymenoptera. Pompilidae. Pepsinae.

Tarantula Hawk, (Pepsis aquila)

This week I was lucky.  I found one resting at night, immobile and easy to trap, with the intention being of photographing her the next morning.  Once the sun rose I chose a suitable spot, set up the camera and tipped her onto the log in front of the lens.  I managed to snap a few images before she warmed up, cleaned herself, climbed up the tree trunk and took to the air.

Tarantula hawks belong to the family Pompilidae which has a large number of species many of which are spider hunters.  The genus Pepsis consists of about 300 species mainly distributed throughout Central and South America.  The adults are commonly seen taking nectar from flowers.

The large size of the Tarantula hawk enable it to hunt larger prey, as the name suggest, tarantulas.  It is thought that the females are particular about the species of tarantula that they hunt.  When a female finds a victim she will touch it with her antennae, the spider has a particular chemical odor that will identify it as the unfortunate chosen one.

Having made her selection the killer wasp grabs the tarantula by the leg and attempts to turn it over so she can inflict the paralyzing sting to the underbelly.  This is not without some danger to the wasp as its large prey can occasionally reverse the role and kill the killer.  Invariably though she delivers the coup de grace and the now immobilized spider can be dragged by the wasp to the spiders own burrow, there she lays a single egg, buries the victim and leaves it to its grisly fate.  While grappling in this life or death battle with the spider, the female wasp emits a pungent odor, the scent of imminent victory, whose real function is unknown.

As if being buried alive was not dismal enough, the egg hatches and because the spider is only paralyzed, not killed, the larva begins to consume the living flesh of the spider.  Eventually, once the feast is concluded, the larva spins a silken cocoon, pupates and sometime later a new assassin will emerge and repeat the process.

I see many smaller Pompilid wasps as I walk the trials.  I have watched them catch, sting and drag Wandering Spiders, (Cuppienius spp), to a burrow in a similar fashion.  Normally they are solitary but last week I noticed a group in a collective frenzy on the forest floor.  There seemed to be something at the center of the group that had captured their attention but I could not make out what it was.  The wasps were tumbling over each other to get at the object of interest but whatever it might have been will remain a mystery.

Pompilid sp. Hymenoptera. Pompilidae. Pepsinae.

Pompilid sp Searching for Something

One final wasp that I saw last week, or rather the nest of a wasp, was the unmistakable construction of a Mud-dauber Wasp belonging to the family Sphecidae.  These wasps are found globally but only six of the known species are native to the Neotropics.  What they may lack in species diversity they make up for in numbers, they are very common.

The tubes are made from mud that the wasp has collected from damp ground and fashioned into elongated cells.  These wasps, like the two species mentioned above are spider feeders.  These ones hunt smaller spiders which are dispatched in the same fashion.  Each of the mud cells is packed with paralyzed victims upon which an egg has been laid.  When the cell is full it is sealed and the spiders are left to suffer in immobilized silence.   These cells I noticed on the side of a tree but it is not uncommon to find them on the outer walls of buildings.

Sphecidae sp. Hymenoptera. Sphecidae.

Mud-dauber Wasp Nest – Cells of Lingering Death

Nameless Wonders

The fungi continue to produce their distinctive fruiting bodies.  Some of them are very eye-catching and some of them are compelling due to their strange appearance.  The stunning yellow mushrooms were found growing from the soil beneath the bamboos.  They were large but brittle, when touched they fell over.  Mushrooms appear overnight and only last a short time as they release the fungal spores into the air.  I found the second group of fruiting bodies growing from a dead branch on the forest floor.  They look like miniature branched corals reaching up and pointing to the heavens.  They were very small but the gregarious, monochrome white-tipped black stipes certainly attracted attention.

Agaricales sp. Osa Peninsula. Costa Rica.

Unidentified Mushroom

Xylaria sp. Xylariaceae.

Candle Snuff Fungus, (Xylaria sp)

Looking But Not Seeing

Harvestmen or Daddy Long Legs are strangely fascinating creatures.  They are, along with the spiders and scorpions, arachnids.  There are approximately 5,000 species of Harvestmen in the Order: Opiliones and most of them are found in the Neotropics.  Many people are familiar with these odd-looking creatures with the small globular body suspended between eight long filamentous legs.  The pedipalps at the front of the head are small and have weak claws at the tips.  They are commonly found on tree trunks where they hunt and feed on small arthropods such as mites and springtails.  They have the undeserved reputation of being one of the most venomous animals on the planet.  There is no factual basis for that claim but once one person says it and another repeats in then it becomes a fact with no standing in reality.

Opiliones

Daddy Long-legs with Legs Covered in Mosquitoes

They would appear to be very vulnerable to predation but they do have ways of avoiding becoming a meal.  They are generally nocturnal and cryptically colored so they blend in with the background.  If physically attacked then they can drop the leg that has been caught, (appendotomy).  The leg continues to twitch serving to hold the attacker’s attention.  They also have repugnatorial glands on the body from which they release a variety of foul smelling chemicals which repel a continuing attack.  If predatory ants are on the hunt, the harvestman lifts itself as high as the legs allow and then remains motionless.  The ants will only attack if they detect motion.

Having taken the photograph and then looked at it in detail I noticed something that I had not seen when I was looking at the animal on the tree, it’s legs were being covered by what appeared to be blood-sucking mosquitoes.  Searching online I could find very few records of mosquitoes feeding on the blood of other arthropods.  Obviously the harvestman has not developed a means by which to keep these specialist predators at bay but without further investigation it may well be that the mosquitoes were simply using the legs as a place to rest.

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

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