Eat Better to Look Better: The Relationship between Food Availability, UV Brightness of the Major Claw, and Mating Success of the Fiddler Crab Austruca lactea.

Abstract

Many factors affect male fiddler crab courting and female choice during underground mating, including claw-waving patterns, claw-waving frequency, hood structures, burrow quality, and visible and ultraviolet signals of the major claw. Under food-limited conditions, fiddler crabs decrease their investments in reproduction-e.g., lower their claw-waving frequency. However, the effect of food availability on the visible or ultraviolet signals important for courtship success is unknown, not only for fiddler crabs, but for crustaceans in general. This is the first study to explore the influence of food availability on the early stages of female choice in Austruca lactea. In the present study, we tested (1) the effect of food availability on the UV brightness of A. lactea's major claw and burrow quality and (2) the correlation between A. lactea courtship success and the UV brightness of its major claw. Our results showed that higher food availability increased the UV brightness of the major claw and enhanced the male's burrow quality. The UV component to the signal is important for courtship success. The males with a UV component of signal on their major claw had a higher courtship success. This is an indication that food availability may affect the attractiveness of male fiddler crabs.