Egg load and mating status of the golden egg bug affect predation risk

Females of the golden egg bug (Phyllomorpha laciniata) lay eggs on the back s of male and female conspecifics, and surprisingly, individuals commonly c arry unrelated eggs. Here, we investigate predation risk from the ant Formi ca rufa during two reproductive stages of the golden egg bug: egg carrying and mating. Ants and an egg-loaded bug were enclosed with an unloaded bug, with a mating pair, or with a mating pair and an unloaded bug. Both mating and egg carrying increased predation risk. Mating increased predation risk because mating pairs were attacked more often than single egg-loaded bugs. When a mating pair was enclosed with an egg-loaded bug and an unloaded bug, the pair was attacked significantly more often than the two single individ uals together, even though ant visitation rates did not differ among prey i tems. Ants attacked egg-loaded bugs significantly more often than unloaded bugs. Egg-loaded individuals suffered lower predation risks when in the pre sence of a mating pair than when in the presence of a single unloaded bug. Thus, predation risk depends on the mating status of nearby individuals. In the field, single individuals are often found with mating pairs; this obse rvation could be explained if individuals decrease their predation risk by associating with preferred prey.