Response by encapsulation of four mealybug species (homoptera: pseudococcidae) to parasitization byAnagyrus pseudococci

Abstract

The frequency of encapsulation of eggs ofAnagyrus pseudococci (Girault) (Hymenoptera: Encyrtidae) by four mealybug species:Planococcus citri (Risso),PL vovae (Nasonov),Pl. ficus (Signoret) andPseudococcus cryptus Hempel (=citriculus Green), was studied under controlled laboratory conditions. The aggregate percentage of encapsulated eggs (AE) and the percentage of efficient encapsulation (EE) (= percent parasitized mealybugs wherein encapsulation prevented the development of all parasitoid larvae) byPl. citri andPl. vovae did not differ significantly (39.0%vs 38.2% AE and 15.4%vs 17.6% EE, respectively), but was significantly higher than inPs. cryptus (16.2% AE and 5.4% EE). Encapsulation byPl. vovae was significantly higher than byPl. ficus (38.2%vs 20.1% AE and 17.6% vs 7.7% EE, respectively). Neither the host plant nor the rearing temperature significantly affected the incidence of parasitoid encapsulation. It is suggested thatA. pseudococci displays a relatively low physiological adaptation toPl. citri; thus, in a citrus grove, for example,ca 40% of the parasitoid eggs might be lost due to encapsulation. The question of a possible association between encapsulation and host—parasitoid relationships among the mealybugs studied andA. pseudococci, is discussed.