Response by encapsulation of four mealybug species (Homoptera: Pseudococcidae) to parasitization by Anagyrus pseudococci.
The frequency of encapsulation of eggs of Anagyrus pseudococci by 4 mealybug species (Planococcus citri, P. vovae, P. ficus and Pseudococcus cryptus) was studied under controlled laboratory conditions. The aggregate percentage of encapsulated eggs (AE) and the percentage of efficient encapsulation (EE) (=percentage parasitized mealybugs wherein encapsulation prevented the development of all parasitoid larvae) by P. citri and P. vovae did not differ significantly (39.0 compared with 38.2% AE and 15.4 compared with 17.6% EE, resp.), but was significantly greater than in P. cryptus (16.2% AE and 5.4% EE). Encapsulation by P. vovae was significantly greater than by P. ficus (38.2 compared with 20.1% AE and 17.6 compared with 7.7% EE, resp.). Neither the host plant nor the rearing temperature significantly affected the incidence of parasitoid encapsulation. It is suggested that A. pseudococci displays a relatively low physiological adaptation to P. citri; thus, in a Citrus grove, for example, c. 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 and A. pseudococci is discussed.