Quantitative ethogram of male reproductive behavior in the South European toothcarp Aphanius fasciatus

This work provides an ethogram of male reproductive behavior in the most widespread Mediterranean killifish, the South European toothcarp Aphanius fasciatus. The ethogram was obtained by video-recording the behavior of breeding groups under aquarium conditions. The behavioral analysis revealed the existence of seven behavioral states, with the expression of different forms of male-male competition: single and multiple courtship, single and multiple spawning, aggression, homosexual courtship, and postmating cannibalism. These behaviors were organized into sequences that followed a first-order Markov chain. Single courtship was the most prevalent behavior, but more than one male, from two to five, could participate simultaneously in courtship and spawning. Results suggested that the breeding system is based on mate monopolization, with high levels of sperm competition and parasitic spawning. Results are discussed in light of the current literature on alternative mating tactics and male-male competition in teleost fishes.