Timing of sneaking behavior in the dusky frillgoby Bathygobius fuscus sneaker males

Published: 22 December 2022| Version 1 | DOI: 10.17632/rvf9nhvbbx.1
Takeshi Takegaki


Sneaking is a parasitic reproductive behavioral tactic for stealing fertilization opportunities from other males that monopolize females; therefore, sneaker males always face sperm competition. The timing of sneaking is an important trait that contributes to their fertilization success. In the dusky frillgoby Bathygobius fuscus, an intertidal gobiid fish, spawning between a nest-holding male and a paired female continues over several hours. We investigated the behavior of sneaker males of this species in the wild by examining the number of sneaker males around the nest, aggressive interactions between sneaker males, sneaking attempts, and sneak intrusions as indices of their sneaking motivation. Pair spawning lasted for 23.7–192.8 min, during which a maximum of 0–23 sneaker males were observed around the nests. All indices of sneaking motivation, except the number of sneak intrusions, significantly decreased with time elapsed since the pair spawning began. This suggests that sneaking motivation was high at the early stage of pair spawning. Early sneaking may contribute to high fertilization success of sneaker males, likely owing to the long-surviving effect of their long-lived sperm



Nagasaki Daigaku


Behavioral Ecology