Data from: A test of male infanticide as a reproductive tactic in a cichlid fish

Infanticide and offspring cannibalism are taxonomically widespread
phenomena. In some group-living species, a new dominant individual taking
over a group can benefit from infanticide if doing so induces potential
mates to become reproductively available sooner. Despite widespread
observations of infanticide (i.e. egg cannibalism) among fishes, no study
has investigated whether egg cannibalism occurs in fishes as a result of
group takeovers, or how this type of cannibalism might be adaptive. Using
the cooperatively breeding cichlid, Neolamprologus pulcher, we tested
whether new unrelated males entering the dominant position in a social
group were more likely to cannibalize eggs, and whether such cannibalism
would shorten the interval until the female's next spawning. Females
spawned again sooner if their broods were removed than if they were cared
for. Egg cannibalism occurred frequently after a group takeover event, and
was rarer if the original male remained with the group. While dominant
breeder females were initially highly aggressive towards newcomer males
that took over the group, the degree of resistance depended on relative
body size differences between the new pair and, ultimately, female
aggression did not prevent egg cannibalism. Egg cannibalism, however, did
not shorten the duration until subsequent spawning, or increase fecundity
during subsequent breeding in our laboratory setting. Our results show
that infanticide as mediated through group takeovers is a taxonomically
widespread behaviour.