Maternal aggression and post‐hatch care in red swamp crayfish, Procambarus clarkii (Girard): The influences of presence of offspring, fostering, and maternal molting

Abstract

A series of experiments investigated aspects of maternal aggression and care in brooding (tending hatched juveniles) red swamp crayfish (Procambarus clarkii),using a resident‐intruder paradigm. In Experiment 1, maternal female residents won a significantly higher proportion of aggressive encounters than did intruding Form I males. When separated from one's brood for 24 hr, this maternal status effect disappeared, but both maternal care and a significant reproductive status effect reappeared upon reunion. Experiment 2 revealed that maternal care is provided for a brood other than one's own (i.e., fostering) and even after a maternal phase molt. Experiments 3 and 4 demonstrated a significant maternal resident contest outcome advantage against non‐maternal female intruders, and post‐molt maternal care and aggression. Also, there was a continuation of heightened aggression even briefly after other aspects of maternal care had ceased. These effects of presence of brood on contest outcome, fostering, and post‐molt maternal care and aggression (accompanying and after cessation of maternal care) are the first demonstrations of these phenomena in crustaceans.