Developmental biology of Platygaster diplosisae Risbec and Aprostocetus procerae Risbec

Abstract

Platygaster diplosisae (Risbec, 1956) and Aprostocetus procerae (Risbec, 1956) are ovo-larval and pupal parasitoids, respectively of Orseolia oryzivora (H & G). The reproductive biology of the two parasitoids was studied by authors, but their developmental biology was not yet explored. Mature rice galls due to O. oryzivora were collected from irrigated rice fields of Karfiguela and Boulbi, located in Western and Central Burkina Faso respectively. They were kept in wooden cages (45.5 cm × 44.7 cm × 59.5 cm) or plastic buckets (32 cm × 29 cm) covered with a fine mesh mosquito net to prevent insects from escaping after emergence. Fourteen-day rice plants of the variety FKR 28 were infested by adults of O. oryzivora in two metal cages (1.52 m × 1.26 m 1.65 m) (10 pairs of adults for each cage). In this way, it was possible to maintain a continuous culture of O. oryzivora that allowed the mass rearing of the parasitoids. The studied biological parameters of the parasitoids included, duration of post-embryonic development, lifespan, fecundity and fertility. The results revealed that the development time of A. procerae from egg to adult was 28 ± 6.18 days and that of P. diplosisae 33 ± 6.94 days. The mean incubation time of P. diplosisae eggs was 16 ± 1.98 days and that of A. procerae was 3.2 ± 1.78 days. Each of the two parasitoids exhibited three stages of larval development. The mean durations of the three larval stages of A. procerae were 5 ± 2.78, 3 ± 1.14 and 3 ± 0.55 days, respectively. For P. diplosisae, these figures were 2.2 ± 0.54 and 3 ± 0,71 days respectively. The pupal development time of P. diplosisae was 10 ± 2.26 days while that of A. procerae was 15 ± 3.92 days. The average number of ovarian eggs of the female of P. diplosisae was 213 ± 32.34 while the average number of parasitoid eggs inside the larva of O. oryzivora was 106 ± 18.43. The average number of ovarian eggs of A. procerae was 11 ± 2.93. The lifespan of adult females of A. procerae (15 ± 3.64 days) fed with honey was longer than that of males (7 ± 4.77 days) fed under the same conditions. Male’s longevity was significantly different from that of the female depending on food and temperature. Longevity of honey-fed adult females of P. diplosisae (6 ± 3.31 days) was longer than that of honey-fed adult males (3 ± 0.55 days). The life span of unfed adult females (3 ± 0.71 days) as well as that of unfed adult males (1 ± 0.15 day) were shorter. The results obtained from the two parasitoids associated with Orseolia oryzivora could be used for the development of a biological control of Orseolia oryzivora.