An overlooked reproductive stage: Foraging activity of crayfish females with glair glands

Compared with non-reproductive individuals, egg-carrying crayfish females reduce locomotion and feeding, adopt more cryptic behaviour, and prioritise egg incubation and early juvenile care. However, female behaviour during the final stage of reproductive maturation, marked by glair gland development, remains understudied. This study investigated feeding activity in non-reproductive, glair gland-bearing, and egg-carrying marbled crayfish (Procambarus virginalis). Two experiments were conducted: (i) analysis of foraging using a functional response approach and (ii) assessment of feeding with and without shelter, a key habitat resource. All groups exhibited a Type II functional response. Handling times differed significantly among reproductive stages, while attack rates remained similar. Feeding rates were highest in non-reproductive females, lowest in egg-carrying individuals, and intermediate in glair gland-bearing females. Shelter presence increased prey consumption only in non-reproductive females, likely reflecting a stronger response to perceived safety. In contrast, shelter had no significant effect on feeding in glair gland-bearing or egg-carrying females, suggesting that reproductive-stage-related processes may reduce responsiveness to environmental influences, thereby reducing feeding activity. These results indicate reproductive-stage-specific behavioural plasticity and highlight the importance of standardising experimental conditions, particularly in laboratory studies of species that frequently reproduce, such as marbled crayfish.