OBSERVATIONS ON THE REPRODUCTIVE-BIOLOGY OF 2 PARASITES OF HYLESINUS-VARIUS AND PHLOEOTRIBUS-SCARABAEOIDES (COL, SCOLYTIDAE) - CHEIROPACHUS-QUADRUM (HYM, PTEROMALIDAE) AND DENDROSOTER-PROTUBERANS (HYM, BRACONIDAE)

Observations on the biology of Cheiropachus quadrum (Hym : Pteromalida e) and Dendrosoter protuberans (Hym : Braconidae), were conducted. Bot h species are the main parasites of the olive bark beetles Hylesinus v arius and Phloeotribus scarabaeoides (Col : Scolytidae) in the South o f Spain. Results have shown that an increase in body size of the host does not imply an increase in parasite efficiency. In fact, host size inversely affects parasite efficiency for C. quadrum. Bearing in mind this fact, the abundance of the host and the ease of its rearing in th e lab, it is therefore advisable to use P. scarabaeoides as the host f or mass rearing of the parasites studied here. On the other hand, the presence of white light is a negative factor for parasite longevity an d fecundity. The pupae and all larval instars are parasitised. C. quad rum does not have a preference for any particular stage or larval inst ar of the host whilst there is a preference for the third and fifth la rval instar by D. protuberans. With respect to the sex ratio of parasi tes, an increase in the number of males increases the fecundity of the females. The results obtained in this study can be considered essenti al in the development of a biological control system for olive bark be etle pests based on an increase in the population of C. quadrum and D. protuberans.