Trockenzeit-Libellen aus dem indischen Tiefland (Odonata)

Abstract

Dry Season Dragonflies of Indian Lowlands Only some 60 species, i.e., about 10% of the dragonfly fauna of the Indian subcontinent can be observed during the premonsunal dry season in the plains of India. 42 of them (table 1) were registrated by the author on excursions in New Delhi, Calcutta, Madras, Trivandrum and the surroundings of these large towns in the last decade of April and in May 1979. 260 specimens have been catched for collection, between them two males and one female of a hitherto unknown species (Agriocnemis keralensis), whose description is given in English (fig. 1). Excluding Pantala flavescens in southern India and possibly Brachythemis contaminata throughout the whole country, imaginal specimens of all species were very scarse in numbers and the pupulations were found isolated in restricted favourable localities. The deficiency of oxygen in the upheated water bodies seems to be the main reason for the seasonal scantiness of dragonflies in the Indian lowlands. About 30% of the dry season dragonfly species are distributed well beyond the borders of the Oriental zoogeographic region, whereas only some 3% of the mountain species are not restricted to this region. This comparision shows very clear the high degree of adaptive abilities and vitality of the lowland dragonflies.