Evolution: storm induced natural selection (Evolution)

by David Turell , Monday, April 27, 2020, 21:28 (1461 days ago) @ David Turell

A new study supports the relationship of big lizard pads and Caribbean hurricanes which we mentioned before:

https://phys.org/news/2020-04-hurricanes-evolution-island-lizards.html

"Lizard groups that more frequently experience hurricanes evolve larger toepads than those that experience relatively fewer hurricanes, according to a new analysis that spans 12 island populations of Anolis sagrei lizards and, separately, 188 Anolis species with ranges from Florida to Brazil.

"Scientists have known for a long time that lizards on the Caribbean islands have larger toepads than those on the mainland. But this physical difference has never been definitively linked to an evolutionary response to hurricanes. Hurricanes happen so infrequently that researchers used to think their effects would be erased by natural selection favoring normal conditions.

"'What we found is that hurricanes actually do have evolutionary effects on lizards that span both geographic and phylogenetic scales," said Colin Donihue, a postdoctoral fellow in biology in Arts & Sciences at Washington University. "We showed that hurricanes affect a single anole species in Turks & Caicos, and those effects are likely inherited to the next generation—suggesting an evolutionary change. The effects are paralleled across 12 island populations of a different anole species, and ultimately can be detected across an entire genus of very distantly related anole lizards."

***

"'Correcting for things like differences in body size, we found that island populations that had been hit by hurricanes more [frequently] had larger toepads," Donihue said. "Hurricanes seem to be having some sort of additive effect on the evolution of these lizards—that the more hurricanes you have, the larger toepads you have, on average."

"'Toepads might be a key trait for helping lizards hold on tight to the vegetation during storms," he said. "But there's probably a tradeoff between the traits that make you really good at surviving a hurricane and the traits that make you really good at being a lizard day in, day out."

Comment: It seems like a good theory. Bigger pads will hold on better in high wind speed and natural variation will allow those with bigger pads to survive.