Biological studies of Brachyserphus abruptus (Hym.: Proctotrupidae), a nitidulid parasite.

Data are presented on survival, fecundity, and hosts of Brachyserphus abruptus (Say), a solitary internal parasite of nitidulid (sap beetle) larvae. In the laboratory these wasps have been successfully reared from Carpophilus hemipterus (L.), C.freemani Dobson, C. lugubris Murray, Stelidota geminata (Say), S. octomaculata (Say), S.ferruginea Reitter, Glischrochilus quadrisignatus (Say), Lobiopa insularis (Casteinau), and Haptoncus luteolus (Erichson). Field collections of B. abruptus have been made from S. geminata, S. octomaculata, C. hemipterus, C. lugubris, L. insularis and H. luteolus. Oviposition continues throughout most of the adult female’s lifetime. Under laboratory conditions life expectancy of females was ca. 6 days. Mean number of progeny reaching adulthood per female was 57, with a 1 : 1 sex ratio. First and 2 nd instar nitidulids were suitable for successful development of B. abruptus. Third instars were attacked by B. abruptus but were not successfully parasitized. Parasite development required 29 days in 1 st instar hosts and 27 d. in 2 nd instars. Percent parasitism in 1-st instar C. hemipterus averaged 65 % and for 2-nd instar 45 %. After parasitism, larvae of C. hemipterus surviving to become adults averaged 0.6 % for I-st instar, 9.3 % for 2-nd instar, and 90 % for 3-rd instar.