Harlequin Beetle: Hiding In Full View   Leave a comment

Wildlife, nature, fauna and flora of Costa Rica.

Over the past week the rains have continued, now sometimes during the day as well as at night.  There have been some heavy downpours.  One thing that can occur this time of year are the climatic phenomena known as temporals.  Clouds will settle over an area for some days producing grey, overcast conditions with constant rainfall.

The water level in the creek has risen, not drastically, but enough to secure a steady flow.  The mango orchard is the scene of a lot of activity with so many animals coming to feed from the bumper crop that is presently hanging from the trees.  During the day spider monkeys and white-faced capuchin monkeys can be seen greedily feasting on the abundant and ripening fruits.  Monkeys are very wasteful feeders, they pluck a fruit from the branch, take a bite and throw the remainder to the ground.  Here the white-nosed coatis and agoutis take advantage of a free meal falling from above.

At night the mangoes are visited by kinkajous in the trees and pacas on the ground, the nocturnal cousin of the agouti.  All manner of insect life feeds on the fermenting mangoes, everything from flies, bees, butterflies and at night, moths.

The Mighty Harlequin Beetle

One night while returning to my cabin I noticed a beetle, a very large beetle, on the vertical surface of a tree trunk.  It was late and I did not want to set up the camera equipment so I placed the beetle in a collecting bottle in order to photograph it the next day.  Beetles, due to the huge number of species are not always the easiest creatures to identify but there was no problem with this one.  The color, the pattern, the long, curved antennae and the thin extended front legs allowed me to identify this one immediately.  This was a Harlequin Beetle, (Acrocinus longimanus).

Coleoptera. Cerambycidae. Acrocinus longimanus. Osa Peninsula. Costa Rica.

Harlequin Beetle, (Acrocinus longimanus)

The exquisite geometric black and red markings over a green background of this handsome beetle would appear to make it stand out rather obviously in the hand.  But place it on a lichen covered tree trunk and it disappears from in front of your eyes.

Harlequin Beetles belong to the Longhorns of the family: Cerambycidae and are found throughout the Neotropics.  If a tree noted for producing copious amounts of sap is either injured or damaged then you can expect many Harlequin Beetles turning up as if from nowhere.

Harlequin Beetle. Felipe del Bosque. Osa Peninsula. Costa Rica.

Strangely long front legs of a Harlequin Beetle

Both sexes have long extended front legs but the males much more significantly longer.  It is thought that this is in some way related to mating.  The beetles are active both day and night.  The females prefer rotting wood already proliferated with bracket fungus in which to lay her eggs.  The resulting larvae then complete their development within the now dead wood.  For this reason they can be regarded as speeding the decay of non-living trees rather than a pest of live wood.

While I was taking the pictures, I noticed that the beetle was covered, particularly around the head and bases of the wings with a myriad of mites.  Mites are arachnids and can be parasitic or predaceous upon other arthropods.  They sometimes feed on the secretions of their hosts and other times use them as a means of transport, phoresy.  Phoretic mites usually glue themselves to the host in order to hitch a ride without falling.  Mites are a specialized and difficult group to study and the people that do so are few and far between.  It is way beyond my ability to identify these mites.  It could well be that they are one of the nymphal stages.  There appear to be both orange and white colored mites.  Once again I am at a loss as to whether these are of different species.  The beetle did not appear to be too agitated by its infestation.  If anyone has further information to help elucidate what was happening then I would be happy to hear from you.

Coleoptera. Cerambycidae. Acrocinus longimanus. Osa Peninsula. Costa Rica.

Close up of the Harlequin Beetle head showing the mite infestation

A Fleeting Glimpse of Blue

At the present there are lots of trees producing fruit, notably the figs.  In some areas the ground is covered with figs in various states of decomposition.  The scent of rotting fruit is irresistible to many insects that come to imbibe the liquifying and fermenting meal it provides.  Some of the butterflies are drawn this intoxicating feast, the commoner ones being species of Blue Morphos.

As I was walking through a sunlit path in the forest I was met with a bright metallic blue morpho taking to the air from down by my feet.  I had disturbed its meal of fig juice from the fruits that were lying everywhere.  It was not going to be so easily dissuaded though and landed a short distance away on a tree trunk.  Here it would wait momentarily for a few moments before circling around and taking up where it had left off feeding on the ground.

While it was stationary I took the opportunity to capture its image.  I noticed one of the hindwings was damaged and the brilliant electric blue coloring of the upperwing for which the butterfly is named was visible.  There are three species of blue morpho in this area, each one distinct from the other.  This one was a male Morpho menelaus.

Lepidoptera. Nymphalidae. Morphinae. Morpho menelaus. Osa Peninsula. Costa Rica.

Torn hindwing of male Morpho menelaus reveals blue color of upperwing

Morphos are large butterflies and are unmistakable in flight due to their size and eye-capturing iridescent blue coloration.  In flight they move with slow wing beats up and down, left to right.  Each time they open their wings the bright blue appears but when the wings close then it disappears.  For any predator trying to follow the flight path of a blue morpho, and with flying butterfly then that is generally going to be a bird, all that it is going to see is a stroboscopic flashing of metallic blue from different points in front of it making it impossible to follow.  But there are always around systems and some birds, Jacamars, which are related to kingfishers, have learned how to intercept the morpho on its flight path.  The perches of jacamars will have the discarded wings of morphos littering the ground below where they have eaten the bodies of the butterfly and dropped the wings.

Butterflies belong to the insect order: Lepidoptera, which translates into scaled wings.  From the photograph you can see the lines of overlapping powdery scales that cover the wings.  With the morphos the scales on the upperside of the wing are transparent but layered.  In effect each scale acts as a prism.  Light entering the scale is broken down and the blue light is refracted back out.  So the blue coloration is not due to pigment but rather the refraction of light.

One of the other species of morpho found in this area, Morpho cypris, is one of the most highly iridescent insects on the planet.  It will only be seen in the morning and only found flying at the level of the canopy, 100 feet or more above the ground.  Should you be on a tree platform or a canopy bridge you will be astounded to see what appears to be a diffuse metallic blue sphere floating through the tree tops.  It is an absolutely phenomenal sight.

Unseen Red

One of the more frequently encountered snakes in the area is the Tropical Bird-eating Snake, (Pseustes poecilonotus).  They are one of a handful of larger snakes to be found here, which is good in as much as that limits your choice when it comes to identification.  They can grow to about 6 feet in length.  Most of the individuals I have found are a muted green color with pale red bands along the body.  The belly is usually yellow and the top of the head black.

On one of my walks, in the open before the forest entrance, I heard a rasping sound which I knew immediately as the rubbing of dry scales against each other heralding the presence of a snake.  I looked down and there close to the forest edge was a beautiful Tropical Bird-eating Snake.  This one was so striking as it did not have the normal coloration but was rather an overall vivid scarlet with tinges of orange suffused around the lips.

Reptilia. Squamata. Serpentes. Colubrinae. Pseustes poecilonotus. Osa Peninsula. Costa Rica.

Unusually red-colored Tropical Bird-eating Snake, (Pseustes poecilonotus)

As the name suggests these snakes eat birds as well as chicks and eggs from nests.  They are non-venomous but can be irascible.  If you approach too closely they will laterally flatten the neck to give the appearance of being larger than they are.  They open the mouth and hiss which gives them the alternative name of “Hissing or Puffing Snakes”.

Tropical Bird-eating Snake. Philip Davison. Felipe del Bosque.

Defensive threat pose of a Tropical Bird-eating Snake

As I bent down to take a closer photograph, the snake duly obliged by living up to its name, flattening its neck, opening its mouth and letting out a hiss of discontent at my presence.  I didn’t bother it for too long, took the pictures and left to let the serpent continue about its business.

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

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