On the relative abundance and interspecific competition among different thrips species (Thysanoptera: Insecta) infesting flowers of Tagetes erecta L. in the Doon Valley.
The relative abundance and interspecific competition of various thrips species in the flowers of Tagetes erecta were studied in the Doon Valley, Uttar Pradesh, India, in 1979-80. During flowering from July/August to April, T. erecta was attacked by Thrips flavus, T. coloratus, T. hawaiiensis and Microcephalothrips abdominalis, Haplothrips gowdeyi and H. ganglbaueri. T. flavus occurred for longest (8 months) and was the most abundant species (43.4%), followed by M. abdominalis (25.2%) which occurred for 5 months. T. coloratus and T. hawaiiensis constituted 12.7 and 12.33% of the total population, respectively, and occurred for 6 months. H. gowdeyi and H. ganglbaueri occurred for only 2 months and their relative abundance was 3.17 and 3.18%, respectively. The peak of the populations occurred at different times due to interspecific competition. The rise in the population of T. flavus was associated with a decline in temperature and maximum density was attained at 12°C, but climatic effects had no marked effect on the other species. Females dominated the population of each species.