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Aligarh Muslim University (1990)

Ecological studies on some occasionally gregarious acridoids of North India

Basit, Abdul

Titre : Ecological studies on some occasionally gregarious acridoids of North India

Auteur : Basit, Abdul

Université de soutenance : Aligarh Muslim University

Grade : Doctor of Philosophy (PhD) in Zoology 1990

Résumé partiel
The adults of Oedaleus abruptus and Gastrimargus africanus are found in short and tall grasslands/ respectively. They migrate into crop fields when in advance stages while early nymphal instars remain within the grasses like Cyperus rotunduS/ Seteria glauca/ Paspalum distichum/ Andropogon adoratus/ Panicum psilopodium and Cynodon dactylon . The adults are distinguished by the hind wings basally bright yellow and with a thick complete dark band and with the hind femur ventrally blue in Gastrimargus africanus while Oedaleus abruptus can be distinguished from its smaller size and incomplete hind wing fascia. Both these species are found in a mixed population with each other at all stages. The life stages in laboratory conditions have shown that under constant conditions there can be four complete generations in a year however, the number of generations may be reduced to 2-3 in natural population. Adults are found reproductively active in rainy season and in the months of September, October, March and April but do remain active in winter season without reproductive activities. The act of copulation is on a typical acridian pattern but with a longer duration of about 100 minutes as compared to other acridids. Oviposition is completed in 1^ hour and can be completed in 45 minutes. The size of the egg pod is variable in both the species. The average number of egg- pods per female in Oedaleus abruptus was 6,96±0.36 (isolated condition) and 6.40±0.34 (crowded condition) and the size of the egg-pod laid earlier was longer than the egg pod laid later while in Gastrimargus africanus the average number of egg-podsper femalewas 8.04±0.35 (isolated condition) and 7.08±0.33 (crowded condition). The isolated and crowded conditions show some effect on the fecundity of females of these two grasshoppers. The average egg-pods and eggs of these two species was found to be 57.94 (isolated condition) in Gastrimargus africanus and 14.53 (isolated condition) in Oedaleus abruptus and was also found different in both cases under crowded conditions.

Présentation et version intégrale (Shodhganga)

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