Survival is being in the right place at the right time
September 10, 2012
Evolution occurs when some animals make mistakes while others get it right. Kecia Kerr, Ph.D. candidate at McGill University studied how two species of fiddler crabs respond to swings in temperature when cold water enters the Bay of Panama. She recorded egg hatching times, a response that depends on when mating occurs and on incubation temperatures.
When the temperature is constantly warm, eggs of both species hatch twice each month on the highest night time tides—the best time for larvae to avoid their predators. When exposed to cold temperatures, Uca terpsichores stayed on time by mating earlier, but when temperature changed rapidly during incubation, they released their larvae early or late. Uca deichmanni stayed on time when temperatures changed, possibly by moving their eggs between warm and cold areas in the sediment, but they did not get the timing right when temperatures were too cold.
Kecia, whose STRI supervisors are Rachel Collin and John Christy, hopes her results will help to predict how animals respond to different climate change scenarios.