The interaction of antlions and ants is postulated to be a predator-prey interaction in which the involved parties coevolve. Here, we investigated two issues of potential significance in terms of antlions and ants imposing selective pressures on one another. First, we determined whether trap-building antlions and sanddwelling ants closely co-occurred in an area inhabited by both. In the field, we found that ants were the main potential prey items in artificial traps placed inside aggregation zones of antlions and that Formica cinerea workers comprised the majority of these ants. Second, we checked whether rescue behavior, a type of prosocial behavior displayed by F. cinerea workers and performed towards nestmates captured by antlions, reduced the hunting success of the latter. In the laboratory, we found that rescue attempts were very rarely successful. Overall, caution must be used when considering the coevolution of antlions and ants. Clearly, even though these two organisms can closely co-occur, the rescue behavior of ants seems to be unrelated to the predatory threat from antlions.

Recently, antlion larvae with greater behavioural asymmetry were shown to have improved learning abilities. However, a major evolutionary question that remained unanswered was why this asymmetry does not increase in all individuals during development. Here, we show that a trade-off exists between learning ability of larvae and their hunting efficiency. Larvae with greater asymmetry learn better than those with less, but the latter are better able to sense vibrational signals used to detect prey and can capture prey more quickly. Both traits, learning ability and hunting efficiency, present obvious fitness advantages; the trade-off between them may explain why behavioural asymmetry, which presumably stems from brain lateralization, is relatively rare in natural antlion populations.Electronic supplementary materialThe online version of this article (10.1007/s10071-018-1190-2) contains supplementary material, which is available to authorized users.