Ecology of Otinotus oneratus Walker (hemiptera: Membracidae) on its Host Plant Tamarindus indica

Abstract

This study is on the ecology and population dynamics of the membracid Otinotus oneratus Walker on its host plant Tamarindus indica L. The daily activity of O. oneratus when analysed revealed that it was active during 11:00 and 16:00 hr, and on extremely warmer days. Adults preferred woody internodal parts, while the early nymphal stages fed on the axil of the leaves, and the later nymphs fed on the internodal parts along with the adults. The resting posture of the adults were found to be in position with its head directed upwards on its host plant. The mean number of nymphs resting in a posture facing towards and away from node was 79.7 and 17.1 respectively; with adults, for males and females it was 3.0 and 4.6 upwards facing, and for downwards it was 2.4 and 3.6, respectively. The individuals were sluggish, and when disturbed, moved in a spiral manner around the twig, and stopped after moving some distance. Mating occurred for 5 min, followed by a female preoviposition period of 3 days. Eggs were elongate and white and laid in ‘V’ shaped manner, arranged in two rows with 12-19 eggs in each row. Parental care was exhibited with the females guarding 71.4 to 83.3% of egg masses. The incubation period varied from 8-12 days. Hatching occurred during the morning hours, and the nymphs were slow moving, showing a strong myrmecophilous mutualism, regularly attended by the large black ant Camponotus compressus F. (56.5- 92.9%). Predation by Gonatocerus brevifuniculatus Subba Rao and Mirufens afrangiata Viggiani and Hayat of eggs wqas observed. O. oneratus nymphs mimicked the thorns of the host plant, but they were brightly coloured (in contrast to the twigs). The occurrence of nymphs and adults reached a peak in December and January. The present study also assessed the population dynamics in relation to weather factors.