Female mate choice for male size in a freshwater goby under experimental conditions eliminating inter-male interference

The preference of females for male body size was examined in an experimental environment where direct interference between males was eliminated. In this environment, females preferred to spawn with larger males. To understand the preference of females for larger males, paternal care and egg defence abilities and paternal cannibalism intensity were further tested with respect to the body size of males. The dead egg rate for an egg mass during the paternal care period was not related to the body size of the paternal males. However, larger males could defend their egg masses more successfully against nest intruders than smaller ones. During the paternal egg care period, paternal males often consumed eggs in their nests. In particular, smaller males compared to females caused paternal brood cannibalism. High egg defence ability and low paternal cannibalism intensity are the most plausible reasons for females to choose larger males.