The Effect of Male and Female Body Size on the Mating Behavior of Male Fairy Shrimp, Eubranchipus neglectus

Abstract

ABSTRACT We studied size-related mating patterns in the freshwater fairy shrimp Eubranchipus neglectus in the laboratory. Males were provided with relatively small or large females that they could only sense by vision. We recorded the number of times a male pursued the female (“follows”), the duration of these follows, and the number of times a male attempted to grasp the female. Relatively large males performed more mating behavior than relatively small males. Furthermore, males (regardless of their own size) exhibited more mating behavior towards large than small females. They followed large females more frequently, attempted to grasp large females more often, and had a greater percentage of follows with a grasp attempt with large females. There was no relationship between male to female size ratio and either follows or grasp attempts. These results suggest that male E. neglectus have a preference for larger females; the function of this preference may be that large females have more eggs, a benefit which may help compensate for any possible costs of mating to the male.