Archive for the ‘Oophaga granuliferus’ Tag

Beautiful Deceptions: Mimicking Aposematism   Leave a comment


Wildlife, nature, fauna and flora of Costa Rica.

The weather continues to favor the visitors to the Osa Peninsula.  August normally sees the transition from rain to really heavy rain which continues through September into November. But the days remain hot and sunny, and certainly not every night, but definitely last night, we were entertained by an electric storm with lots of lightning illuminating the forest and lodge accompanied by the crashes of thunder which rattled the structure of all the buildings.  All of this, along with the driving rain lashing down, probably made for a sleepless night for one and all.  This morning though, as the sun rose over the Golfo Dulce, it did so without a cloud in the sky, promising yet another beautiful day.

Rainforest Rhythm

The storm seemed to have dampened the enthusiasm of the animal life as there were not many birds active at first light and the butterflies made a slow start of it but as I sit and write at mid day everything appears to have returned to normal activity.  The Scarlet Macaws are making their usual raucous din and a large flock of Golden Hooded Tanagers have been making their way from one fruiting tree to another, eagerly feeding on the ripening feast now available to them.

The grounds have several fig trees which have been producing a copious amount of small figs for several weeks now.  Toucans arrive by the flock on a daily basis.  There are large mixed flocks of multiple tanager species, dacnis, honeycreepers and manikins.  The ever-present large white blooms of the Crepe Gingers are continually attracting the attention of resident Rufus-tailed Hummingbirds and Purple-crowned Fairies which feed on the nectar they provide.  Despite their small size, the Rufus-tailed Hummingbirds zealously guard their food supply, pugnaciously putting much larger invaders of their territory to flight.  The Hermits, both Long-billed and Strip-throated, are more tranquil by nature, and “trapline” the Heliconia blooms, making their daily rounds, flitting at high speed from flower to flower, hovering briefly at each one to take a sip of nectar.

The Hobos or “Hog Plums” have been another month’s long source of fruit now and the Cannonball Tree which has recently been flowering is now starting to produce the distinctive large cannonball shaped fruits from which the tree derives its name.

Rain in A Rainforest:  Life Goes On

This is not the best time of year to see butterflies but nonetheless there are some persistent species, particularly some of the brightly colored long-wings.  I don’t tend to put many guarantees on wildlife sightings, but I can be pretty sure that a visit to one of the constantly flowering Lantanas in the garden areas will reward you with at least four or five species, taking it in turns to move between the orange and yellow flower heads.

Monkeys, coatis and agoutis are not going to be to far away on any day in this area.  Many people ask what the animals do during the rainy season.  It is a rainforest, it rains seven months out of twelve so the animals go about their daily lives as normal.  The Humpback Whales have been giving a fine display today.  Several visitors sitting on the deck of their cabins have seen females with calves close to the shore.

So despite a slow wet start, today turned out just fine, another beautiful day, in more ways than one, here on the Osa Peninsula.

Wildlife spotting is a bit of a hit or miss affair.  No nature guide in his right mind would give cast-iron guarantees about seeing any one particular animal, even it is has inhabited the same spot for a long period of time.  Animal life is not always compliant with ones wishes to see it.  Despite the high levels of biodiversity in tropical rainforests, notoriously they do not reveal their secrets very readily.  It is not like being on the African savannahs inhabited by large mega fauna.  If mammals don’t want to be seen, you will not see them.  I have lived here for ten years and I walk these trails on a daily basis.  In the wet season I can see what has been walking before me from the tracks they have left in the soft earth.  I have seen the tracks of Baird’s Tapir on more than a few occasions.  It is an animal about the size of a Shetland Pony and despite having seen their tracks, even close to my cabin, I have never seen a tapir in this area.

Obviously Aposematic

However there are animals that do want to be seen.  One can think of the bright red color of the Scarlet Macaw.  Along with many other species of parrot, macaws are gregarious birds.  Red is the complementary color to green, the background color of the forest, so it probably aids the macaws as a visual signal within the group.  Think of all those brightly colored, slow flying butterflies, the Heliconiids or Long-wings.  Why would a butterfly want to appear so visibly obvious, they are patently not trying to hide?  The reason is that they contain cyanide.  It would not be in the interests of any predator to feed on the butterfly and nor would it do the butterfly any good to have such a toxic chemical deterrent if nothing new about it.  So those bright flashy colors are warning colors and animals sporting them are said to display aposomatic coloration.

Rainforest butterflies. Lepidoptera. Nymphalidae. Heliconiinae. Heliconius sapho

Heliconius sapho

This situation very nicely lends itself to two forms of mimicry.  Batesian mimicry is the term applied to non poisonous butterflies mimicking poisonous butterflies.  This form of mimicry only works where there are far more poisonous butterflies or the predators would never learn.  Mullerian mimicry is where all the poisonous butterfies across the board are co-mimics of one another.  And mimicry really does work, quite often you need the butterflies in your hand to assess subtle differences in markings or coloration to allow you to identify one species from another.

Costa Rican Longwing Butterflies. Lepidoptera. Nymphalidae. Heliconiinae. Heliconius cydno.

Heliconius cydo – Can you tell the difference with the species above?

Most amphibians are nocturnal, so any diurnal amphibian hopping around on the forest floor during the day is going to be a fairly easy target.  To this effect many diurnal amphibians have evolved very toxin skin secretions.  But once again, there is no point having a toxic skin secretion if none of the predators know about it.  If they eat the frog it is too late for them and too late for the frog.  Diurnal frogs such as the poison dart frogs have evolved very bright warning colors, another example of aposematic coloration.  The colors tend to be neon-like and almost glow from the forest floor.  If something is sitting there glowing, it is not inviting itself as a meal, it is telling you to keep your distance.

Rainforest Poison Dart Frogs Costa Rica. Amphibia. Anura. Dendrobatidae. Oophaga granuliferus)

You can’t miss it – Granular Poison Dart Frog, (Oophaga granuliferus)

Costa Rican Poison Dart Frogs. Amphibia. Anura. Dendrobatidae. Pyllobates vittatus.

Endemic Golfo Dulce Poison Dart Frog, (Phyllobates vittatus)

Rainforest Frogs. Amphibia. Anura. Dendrobatidae. Dendrobates auratus.

Quite literally – Black and Green Poison Dart Frog, (Dendrobates auratus)

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

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