Explorations into natural history

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We disconnected from the outside world for a week to explore the coastal habitats of Cabo Blanco Absolute Natural Reserve, the first protected area in Costa Rica. No emails, Facebook, Twitter, or connections to our normal lives. Instead, we connected to the people, animals, and landscape of this amazing place. The students worked with faculty mentors (Eben Broadbent, Nathan Muchhala, Noelle Beckman, and myself) to come up with some fun projects.

My group studied the natural history and thermal environment of a caterpillar feeding on Terminalia catappa, commonly known as the Indian or beach almond tree.

cabo blanco caterpillar smallWe don’t know the species identity of this caterpillar. But, we’re hoping to figure it out. Dan Janzen and Lee Dyer helped us narrow our search down to Family Notodontidae and, most likely, subfamily Nystaleinae. In response to our inquiry about the caterpillar’s identity, Dan replied, “Welcome to the Victorian tropics”.

I love to imagine what the experience of early explorers was like. Natural history studies thrived in the Victorian era thanks to Charles Darwin, Alfred Russell Wallace, and many others. These naturalists transformed the field of biology and provided a solid foundation for scientific discovery.

As an ecologist, I’m inspired by and in awe of tropical biodiversity. It’s exciting to discover a species that expert lepidopterists can’t identify. With ~8000 species of moths in Costa Rica, it’s probably not uncommon to encounter one that’s not easily recognized.

Despite not knowing the species name, we studied the thermal ecology of this caterpillar. After observing caterpillars crawling down a tree trunk, we decided to examine the thermal environment of these caterpillars and diurnal variation in leaf temperatures. We also examined the effect of temperature on caterpillar performance (survivorship and feeding rates).

caterpillar on the move small

We found that (1) caterpillars show preferences for leaf temperatures around 30 ºC, (2) caterpillar movement out of the canopy down the tree trunk peaks in the late afternoon, when leaf temperatures are higher and more variable, and (3) caterpillar performance is reduced when leaf temperatures are elevated above or below ~30 ºC.

Many studies examining potential climate change effects on insect performance do not consider microhabitat variation in temperature or insect behavior and movement. Our study highlights the importance of considering these factors when examining insect response to elevated temperatures.

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