Rachel
Collin

It is relatively easy to survey large animals that live on the seafloor but it’s not so simple to survey very small animals that live below scuba diving depths or that live buried deep in the sediment. However, many of these organisms produce free-living planktonic larvae that live in the water. Surveys and DNA barcoding of planktonic larvae in temperature oceans often recover species that have never been sampled as adults. This approach has not been used before in the tropics. The Collin lab team has been using DNA and morphological descriptions to document the larval diversity of Panama and link larvae to their adults.

Embryos and developing larvae are thought to be more sensitive to environmental conditions than adults. Therefore, if we are to understand how climate change will impact marine invertebrates we need to understand how their embryos and larvae respond to predicted environmental changes. In my laboratory, we experimentally challenge larvae and embryos with different temperatures, salinities and oxygen concentrations to understand how these conditions impact growth and survival. We are also documenting the distribution of larvae in the wild to understand what conditions they experience and if they can actively avoid stressful conditions.

Taxonomy — the science of finding, describing and naming organisms — is vital to all biological research, especially to understanding and conserving biodiversity. The shortage of taxonomic expertise relative to the large number of undescribed or undiscovered taxa (the so-called taxonomic impediment) is one of the current challenges facing researchers engaged in identifying, classifying and conserving the world’s biodiversity. My goal is to promote species-level and revisionary taxonomic research and taxonomic training to overcome this challenge for tropical marine invertebrates. To do this, I have developed, in collaboration with other taxonomists, the Training in Tropical Taxonomy program. This program supports two graduate-level courses each year on the taxonomy of groups for which expertise is in particular short supply. Combined with the development of online resources such as how-to videos, glossaries of technical terms, translation tables, keys and species inventories, this supports the growth of the next generation of taxonomists and fosters international information transfer. Learn more at the Bocas ARTS website.

A biological rule called Dollo’s Law posits that evolutionary transitions that involve the loss of features are irreversible. Although this appears to be true in general, some interesting exceptions occur and my lab investigates why. We use the complex life cycles of marine gastropods to see when evolution can run in reverse. Most marine invertebrates have complex life cycles with embryos developing into a planktonic larval stage that eventually settles and metamorphoses into a benthic juvenile. However, in each major group of invertebrates some species have lost this larval stage, developing directly from large yolky eggs to juveniles, which crawl away from the protective egg capsules. Following Dollo’s Law this loss was thought to be irreversible, but we have discovered some exceptions. We study these exceptions, species that have regained larvae, trying to understand why and how these larvae re-evolve.