A little more than twenty years ago, a new fish species was introduced into Laguna de Apoyo, Nicaragua. The bigmouth sleeper, Gobiomorus dormitor, is found in the Nicaraguan Great Lakes and rivers throughout the Caribbean slope of Nicaragua, but did not inhabit Laguna de Apoyo in recorded time. How the Midas cichlids present in this lake respond to the new, voracious predator is the topic of this article, co-authored by Topi Lehtonen, Axel Meyer and Jeffrey McCrary, published in PLoS One.
In this study, the responses of two fish to predators at the nest were compared: Amphilophus zaliosus from Laguna de Apoyo, where the bigmouth sleeper is a recent invader to its habitat, and Amphilophus sagittae from Laguna de Xiloá, where the bigmouth sleeper has been present, apparently, for thousands of years. The two cichlid fish species studied are superficially very similar, but the milenia of exposure to the devastating predatory capacity of the bigmouth sleeper has honed its skills at recognizing the threat of its presence at a greater distance and to respond defensively at a greater distance than the evolutionarily naive Amphilophus zaliosus.
The results of this study have immediate relevance to conservation biology as a science and to the protection of wild nature in Nicaragua. The victim of evolutionary naivete in this study is the arrow cichlid (A. zaliosus), which was discovered by George Barlow and Jeffrey Munsey at the University of California, Berkeley, in 1976. This species is now known to occupy only Lake Apoyo,