EFFECT OF NESOLYNX THYMUS (HYMENOPTERA : EULOPHIDAE) DENSITY ON ITS PROGENY PRODUCTION ON EXORISTA BOMBYCIS (DIPTERA : TACHINIDAE) AND MUSCA DOMESTICA (DIPTERA : MUSCIDAE)

摘要

Nesolynx thymus is one among 20 hymenopteran parasitoids reported to attack the uzi fly, Exorista bombycis, which in turn infests the silkworm, Bombyx mod accounting a cocoon yield loss of 10-20%. A host of factors viz., age and size of host, age andsize of parasitoid, availability of host, temperature and quality of host are reported to influence the reproductive efficiency of the parasitoids. In the present study an attempt was made to record the influence of foraging parasitoid density on their reproductive performance. Two day-old uzi pupae and 2 day old Musca Jomes/ica pupae were offered to varying numbers (1, 5, 10, 15, 20) of 2 day old Nesolynx thymus adults for parasitization. No significant variation was observed for number of pupae parasitized in different treatments comprising both uzi and Musca domestica pupae. The progeny production (59.55 - 95.5 adults when parasitoid density was 5 and 20 respectively on uzi pupa) per pupa increased significantly with increased in the number of foraging parasitoid adults. The sex ratio (M : F) of the parasitoid decreased (1:5.63 - 1:14.33 when parasitoid density was 10 and 1, respectively on uzi pupa) significantly with increase in parasitoid adults.