First report on honeydew excretion by the melon thrips, Thrips palmi karny (Thysanoptera : Thripidae) and its biochemical analysis

Abstract

Sap sucking insects like thrips, aphids, mealybugs, whiteflies exploit the sugar rich phloem for growth and development. The excess sugar in the phloem sap creates osmotic imbalance leading to loss of water from haemolymph to gut lumen. In order to maintain osmolarity, sap sucking insects have developed structural adaptation (filter chamber) and also excrete excess sugar as honeydew through various orifices. The excreted honeydew is known to play very vital ecological role such as natural enemy calling (attracting parasitoids). In this regard scanty information is available on this important aspect for different sap sucking insects. In this study we are reporting for the first time on the composition of honeydew from the major horticultural thrips, Thrips palmi reared on French bean (Phaseolus vulgaris). LC-MS-MS analysis revealed the presence of 15 different sugars majorly inositol, fructose, maltose, glucose and sorbitol @ (130.9 ±0.47μg); (95.1±0.45μg); (60.7 ±0.28μg); (54.2 ±0.40μg) and (28.1 ±0.35μg), respectively.