Biodiversity is the scientific way of describing variety; it is a measure of the total number of distinct species in a defined area. Some biologists assess biodiversity by examining genes within a population, while others invoke the classical “species concept” as a way of defining the richness of life in an ecosystem. Regardless of the measurement tool, high biodiversity is a good thing and is cited as a positive indicator for environmental health.
Costa Rica and its tropical forests are known for its high species richness and biodiversity. Some regard the entire country as an ecological hotspot. With the Atlantic Ocean to the east and Pacific to the west, two distinct weather systems collide where the mountains bisect the country. Traveling east to west, the elevation increases along the Caribbean slope. The cumulative affect of oceanic air and elevation changes result in the formation of distinct microclimates that define multiple ecosystems within small patches of land. Like the Caribbean, the Pacific Slope is geologically diverse. As the mountains sink towards the ocean, the structure and diversity of the forests change. Geographic diversity and climate stability contribute to the staggering biological variety found across the country.
Recent research suggest that scientists have underestimated the diversity of life on the planet. By using a non-variable rubric to estimate tropical insect diversity, we have failed to account for the increasing species richness throughout tropical montane ecosystems. Specifically, Genoveva Rodriguez-Castaneda found that tropical insect diversity increases with increasing elevation(1). Montane forests are defined by plant species that have adapted to narrow geographic and climactic conditions. Each valley or hill creates a microclimate that defines a distinct ecotone (ecotone: transition zone between habitats). As environmental characteristics become increasingly narrow, so do the characteristics of a given niche. These narrowly defined niches promote specialization and diversification. As a result of these observations, scientists now project that there may be six times more insect species than previously suggested.
Today’s images are of a caterpillar belonging to the family Megalopygidae. This sloth-like larvae is an embryonic crinkle or flannel moth species. I have spent several hours trying to identify this larvae to the species level, but I can only offer you the following. Megalopygidae can be found in North America and the Neotropics. The larvae are often called Puss Caterpillars and they have venomous spines that, when touched, can produce a variety of symptoms. In addition to pain and inflammation, a sting can cause headaches, nausea and shock(2). This larva was found in the secondary undergrowth near the Selva Verde Lodge located along the Caribbean Slope.
To photograph this animal, I mounted a Canon 180mm f/3.5 L Macro lens to a 5D Mark II. The rig was placed on my Gitzo Mountaneer tripod and I used mirror lock-up and a cable release to trigger the shutter. Because we were shooting in the shade, I used a gold reflector to direct warm light on the larvae and accentuate the details on the head and spines. All of the images displayed were shot between f/4.5 and f/9.5.
Seven trips down and many more to go... Costa Rica’s biodiversity continues to motivate and amaze!
- Genoveva Rodríguez-Castañeda, Lee A. Dyer, Gunnar Brehm, Heidi Connahs, Rebecca E. Forkner, Thomas R. Walla. LETTER: Tropical forests are not flat: how mountains affect herbivore diversity. Ecology Letters, 2010