There is still no let up in the rainy conditions. The good news is that the days are more overcast than dark and the rain is now falling more as a drizzle rather than a deluge. As with recent weeks the sun has been shining once in a while so hopefully as we move into December the rains will abate and we will be able to say the dry season has started.
Rainforest Diversity – Beetles
The wet conditions have kept me indoors more than I would like. On those occasions that I have been out and about there was not too much animal life to point the camera at. When you read about the diversity of fauna and flora contained within a tropical rainforest you would expect to be surrounded by a non-stop progression of subjects. That is not always the case. However if you persist and concentrate on looking a little more closely at the vegetation then something is bound to turn up.
Beetles are the most numerously named group of animals on the planet. Surely there have to be beetles wherever you look. Well they aren’t as obvious as you might imagine. Many of them are secretive, ground-living or wood-boring insects. Looking diligently at the leaves as I made my way along a sunny path and hoping for at least one or two individuals of any insect to be out I saw a small beetle that I had never seen before. Given that Costa Rica has 47,000 named species of beetle and I would never profess to being a specialist coleopterist, then the fact that I did not know what species I was looking at should come as no surprise.
Long-horned Beetle, (Family: Cerambycidae)
I can generally make an immediate I.D. to family level and that was not hard with this one. The length of the antennae were the give away, the very long length, far longer than the body. This was a small Long-horned Beetle, family: Cerambycidae. This one also had a long pronotum, (the area behind the head), and a very long body. I was guessing it belonged in the subfamily: Cerambycinae. I now had to go and research online to see if I could find the genus and species. Alas, my scrutinizing a great many photographs failed to result in a match but at least I have the image should I find further reference material in the future.
Rainforest Diversity – Fungi
The beetles are matched by the fungi in terms of numbers and also a lack of reference material for the non-specialist to identify them to species level. Many of the biologists working with tropical taxa tend to be specialists. I am more of a generalist and enjoy all forms of life; plants, animals, fungi and no matter whether they are extant or extinct. My areas of specialty are butterflies, reptiles and amphibians. It can be frustrating sometimes when a name cannot be found as that might reveal information about the life-history of the organism and its role in the ecosystem. Essentially it helps establish those links that increase our understanding of the system, what happens if those links are severed and conservation management strategies that would be required to stop the system collapsing.
Hygrocybe sp
So it was that I found a mushroom growing from the side of a rotten tree trunk. I had seen and photographed this species before and, like so many others, had not been abled to identify it to species level. There are 2000 named species of fungi in Costa Rica but estimates of how many species actually exist in this small country are as high as 70 000, so you can see the problem, you may be looking at one of the 68 000 estimated species that have not as yet been discovered.
This specimen was somewhat dried out and partly eaten. The aspect gives a good view of the gills under the cap. Given the features I have to work with I would guess the genus to be Hygrocybe, but I would not be held to that. Within the gills you can also see a fungus fly. These are flies that lay their eggs in the mushroom and when the larvae emerge they are surrounded by a ready food supply.
Rainforest Diversity – Spiders
Spiders are the eighth most numerously named group of animals on the planet. As with the beetles and fungi, reference material is sparse for Costa Rican species. However, this was one I did know. It is not an uncommon spider. They are nocturnal and build very distinctive horizontal webs. It is an Orchard Spider, (Leucauge venusta).
They are not large spiders and can be easily overlooked. But if you get up close you will find it has rather lovely markings. The opisthosoma is patterned with curving bands colored with white, red, yellow and blue.
Orcha)rd Spider, (Leucauge venusta
Orchard Spiders are prone to being parasitized by Ichneumonid Wasps. The wasp finds the spider and injects an egg into its abdomen. The egg hatches and the wasp larva proceeds to suck the spider’s internal bodily fluids. Outwardly this does not seem to affect the spider’s behavior and it continues web building as normal. But then something insidious happens. The wasp larva produces a chemical that allows it to sequester the spiders brain. The chemical changes the spiders web building behavior and it produces a web which is not conducive to capturing insects but rather acts as a protective silken home for the pupating wasp. The zombified spider, now of no value to the wasp, dies. Nature can be both cruel and fascinating at the same time.
Rainforest Diversity – Butterflies
For someone passionate about butterflies I am in the right country. Rainforests cover 6% the total land surface of the Earth and yet contain an estimated 50% of the worlds biodiversity. Costa Rica, with only 0.3% of the planets terrestrial area is estimated to house 5% of the world’s total biodiversity. The Osa Peninsula in the south west of the country is one of the most biodiverse localities in Costa Rica. There are a lot of butterflies here. I have recorded approximately 400 of the 1250 species to be found in this small Central American Republic, that is 32% found at Cabo Matapalo, the tip of this tiny piece of land sticking out into the Pacific Ocean.
Even here on Cabo Matapalo there is a large diversity of habitat and different butterflies prefer different conditions. Many of the butterflies live up at canopy level and are beyond daily recording techniques. There are butterflies that prefer open sunny gardened areas, some can be more commonly found along forest edges. Then there are those presence will only be recorded in the gloomy and shadowy world that exists beneath the canopy, some at higher levels and some always hugging the ground.
I have nothing against bright, gaudy coloration but my liking is for more cryptic and subtle forms which when examined close up are every bit as beautiful as their showy cousins. Among the more subdued colored butterflies are the Browns or Satyrs belonging to the family: Nymphalidae, subfamily: Satyrinae. The Satyrinae are notable for the number of eyespots on the underside of the wings. The ground colors are browns and grays patterned with ochres and umbers.
Two-band Satyr, (Pareuptychia ocirrhoe)
The Two-banded Satyr, (Pareuptychia ocrirrhoe), has white dorsal wing surfaces and a bouncy flight close to the ground which gives it a flickering appearance. I found this one flying along the forest edge on a very overcast day. They respond quickly to movement so you have to approach slowly and deliberately in order for them to stay perched.
The Two-banded Satyr is normally found singly. The larvae feed on grasses, (Poaceae), and the adults feed on rotting fruit and fungi, a diet that may account for them living longer, (several weeks), than other butterflies, (several days).
Veridion Adventures 