Author : Palacio, Isabelo D.P.

Summary : The opiines (Hymenoptera: Braconidae) are important parasitoids of the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae). In an attempt to exploit their potential in integrated control of this pest, field and laboratory studies were conduted to generate information about the biology and abundance of the major species. Based on contribution to overall parasitization, the opiine parasitoides associated with B. dorsalis in star fruit could be ranked in the following order of importance: Biosteres persulcatus Silvestri, (46.53 percent) > B. arisanus (Sonan), (32.82 percent) > B. longicaudatus Ashmead, (15.69 percent) > Opius fletcheri Silvestri, (4.95 percent). Field populations of fruit fly and parasitoids had two peak periods/year, and both were significantly correlated with the abundance of their respective hosts, except B. longicaaudatus. However, their activities were significantly unaffected by size and height of host fruit in the tree. Biological studies on three parasitoids, B. persulcatus, B. arisanus and B. longicaudatus, showed that mating and oviposition commenced on the first day of adult emergence. Highest daily mean fecundity and number of adults produced per female occurred on the fourth day of adult life, and coincided with the peak of egg maturation. B. arisanus preffered newly laid host eggs (1-12 hour), B. persulcatus were partial to incubated eggs (24 hr), and B. longicaudatus favored older larvae (96-120 hr) for oviposition. The egg stages of B. arisanus, B. persulcatus and B. longicaudatus averaged 27.9, 27.0, and 53.5 hr, respectively, and the entire developmental period of each species was one day longer for females than males (figures for maels in parentheses), which were as follows: 17.3 (16.3), 17.6 (16.4), and 17.1 (16.3), respectively. Illustrations and detailed morphological descriptions were made for the different developmental stages of these three species, including their external male genitalia. The three parasitoids were similar in terms of lifetime.