When Do Paederus riparius Rove Beetles (Coleoptera : Staphylinidae) Biosynthesize Their Unique Hemolymph Toxin Pederin?

Pederin analyses of single Paederus riparius specimens reared from the egg and kept for prolonged periods of time show that only the females are able to biosynthesize the substance. Preimaginal stages efficiently store pederin transferred by the females into their eggs and the males’ pederin content decreases slowly over time. Only males with access to eggs con­ taining the substance moderately increase their pederin load. The females begin to accumu­ late the toxin a few weeks after imaginal eclosion and build up reserves for the egg laying period within 60 days. This is discussed with regard to the life cycle of P. riparius. During reproduction, when the females loose pederin due to maternal transfer, they must replenish their pederin reserves. This biosynthesis is not reflected in the amount found per individual.