Biology and Morphology of Chelonus sp. nr. curvimaculatus (Hymenoptera: Braconidae) as a Parasitoid of Pectinophora gossypiella (Lepidoptera: Gelechiidae)

Abstract

A general description of the life stages of Chelonus sp. nr. curvimaculatus, an egg-larval parasitoid of pink bollworm, Pectinophora gossypiella (Saunders), is presented. Pink bollworms were reared in the laboratory on a wheat germ diet. At 29°C, parasitoid eggs (0.12—0.18 mm) begin to eclose ≈22 h after oviposition. Three instars occur in this species. The 1st instar is endoparasitic and ranged in length from 0.14 mm (neonate) to 1.25 mm (≈9 d old, end of the 1st stadium). The 2nd instar also is endoparasitic and is 1.89–3.04 mm long. This stadium lasts ≈2–3 d. The 3rd instar is an average of 3.82 mm long and is endoparasitic early in its development but becomes ectoparasitic toward the completion of its development. This stadium lasts =3 d. The pupal stage lasts ≈6–7 d. Adult parasitoids begin to emerge ≈21 d after oviposition. Parasitized and unparasitized pink bollworm larvae developed through 4 stadia. Larval head capsule widths, body lengths, and weights of parasitized pink bollworms are significantly smaller than those of unparasitized larvae during the 3rd and 4th stadia. Parasitized 4th-instar pink bollworms have a mean head width of 0.8687 mm, body length of 6.28 mm, and weight of 6.9 mg. Fourth-instar unparasitized pink bollworm measurements were 1.0743 mm, 9.31 mm, and 17.7 mg, respectively.