Abstract Title
Evolutionary Impact of Visual Predator Preferences on Naesiotus wolfi Coloration
Abstract
Adaptive radiation as a mechanism for diversification is classically described in the context of interspecific competition for resources. Additional biological interactions (such as predation) are also predicted to promote diversification, yet empirical studies supporting this view are more limited. In a previous study of the adaptive radiation of Galápagos Naesiotus snails we have found that species tend to have shell coloration matching the background they rest on. To test whether this match between shell and background coloration is the result of selection by visual predators, we conducted a field experiment using Naesiotus wolfi snails on Santa Cruz Island. We painted 175 trees with two patches, gray and brown, and then a brown painted N. wolfi shell was set on each patch. After 48 hours, the absence or presence of shells on each colored background was recorded. Preliminary results indicate that the brown shell placed on the gray patch was most often taken when only one of the shells on a given tree was gone. This result supports the idea that visual predators select for N. wolfi shells to best match their surrounding environment to minimize predation, thereby potentially contributing to the diversification of these species on Galápagos.
Evolutionary Impact of Visual Predator Preferences on Naesiotus wolfi Coloration
Adaptive radiation as a mechanism for diversification is classically described in the context of interspecific competition for resources. Additional biological interactions (such as predation) are also predicted to promote diversification, yet empirical studies supporting this view are more limited. In a previous study of the adaptive radiation of Galápagos Naesiotus snails we have found that species tend to have shell coloration matching the background they rest on. To test whether this match between shell and background coloration is the result of selection by visual predators, we conducted a field experiment using Naesiotus wolfi snails on Santa Cruz Island. We painted 175 trees with two patches, gray and brown, and then a brown painted N. wolfi shell was set on each patch. After 48 hours, the absence or presence of shells on each colored background was recorded. Preliminary results indicate that the brown shell placed on the gray patch was most often taken when only one of the shells on a given tree was gone. This result supports the idea that visual predators select for N. wolfi shells to best match their surrounding environment to minimize predation, thereby potentially contributing to the diversification of these species on Galápagos.