Maternity uncertainty in cobreeding beetles: females lay more and larger eggs and provide less care

Cobreeding, which occurs when multiple females breed together, is likely to be associated with uncertainty over maternity of offspring in the joint brood, preventing females from directing resources towards their own offspring. Cobreeding females may respond to such uncertainty by shifting their investment towards the stages of offspring development when they are certain of maternity and away from those stages where uncertainty is greater. Here we examined how uncertainty of maternity influences investment decisions of cobreeding females by comparing cobreeding and single breeding females in the burying beetle, Nicrophorus vespilloides; a species in which females can breed together on a single carcass but cannot recognise their own offspring. We found that cobreeding females shifted investment towards the egg stage of offspring development by laying more and larger eggs than females breeding alone. Furthermore, cobreeding females reduced their investment to post-hatching care of larvae ...