Studies on Allophanurus indicus n. sp., an Egg Parasite of Bagrada cruciferarum Kirkaldy (Hymenoptera: Scelionidae).

Abstract

1. Laboratory studies were conducted on the biology and morphology of the immature stages, and the longevity, fecundity and sex ratio of Allophanurus indicus n. sp., an egg parasite of Bagrada cruciferarum Kirkaldy. - 2. It was observed that the female parasites fight amongst themselves for access to the host eggs, and even drive away other parasites which are in the act of oviposition. - 3. The parasite makes scratches on the surface of the host eggs after parasitisation, by means of the ovipositor, in order to discriminate between healthy and parasitised host eggs. - 4. However, when only a few host eggs are available for oviposition, superparasitism occurs. But only one parasite completes development and emerges successfully from a single host egg. - 5. The first instar larva is 'teleaform', but differs from that of other scelionids whose life cycle has been worked out, in having 2 caudoventral horns, one very long and the other shorter, and in not having antennal processes. - 6. A second instar stage definitely intervenes. - 7. The third instar larva is segmented and has 9 pairs of well developed spiracles. - 8. Under laboratory conditions the fecundity of the parasite varied from 140 to 184, the average being 158. The percentage of emergence varied from 78.57 to 86.08, with an average of 82.4. The average rate of reproduction was 7.1. - 9. The longevity of the parasite, when fed on 10% sugar solution, was 30 to 38 days, the average being 33.4 days. - 10. The females outnumbered the males 3:1. - 11. It is suggested that the preponderence of male parasites from the 13th egg laying day onwards is due to the absence of the the male parasites whose longevity varied from 10 to 15 days.

Nomenclatural Acts

indicus Subba Rao & Chacko, 1961 (Allophanurus), spec. n.