Diversity and Foraging Behavior of Dipteran Pollinators of Physic nut (Jatropha curcas L.) in Thailand

Abstract

             The insect pollinators increase fruits and seeds setting of Jatropha curcas L. Therefore, it is important to understand the diversity of fly species as pollinator and pollination effectiveness. This study was performed at 19 locations and 5 regions in Thailand from March 2012 to May 2014. A total 491 individuals of flies belonging to 30 species, 22 genera and 13 families in order Diptera. Family Syrphidae was the most dominant family representing 8 species followed by Calliphoridae (6 species), Asilidae, Stratiomyidae, Tabanidae, Tachinidae and Tephritidae (2 species). The lowest families with only 1 species each were Bombyliidae, Drosophilidae, Muscidae, Sarcophagidae, Therevidae and Tipulidae. However, family Calliphoridae comprised of the highest number of individual (284 individuals) with contributed 57.84% of the total collected fly pollinators. There were 2 peaks of most abundance in March to May and September to October which related to flowering periods at Supan Buri location. Two species of Eristalis obcuritarsis and Chrysomya megacephala showed the highest abundances occurred during 08.00-10.00 h and declined in late afternoon on male flowers. Whereas on female flowers found both species had a population peaked in the afternoon. Fly preferences on floral sex characters were different among visited female and male flowers. Both of fly species were preferred female flowers rather than male flowers. E. obcuritarsis as compared to male and female flies which were 1:5 and 1:1, respectively. Whereas, male and female of C. megacephala were 1:8 and 1:2 respectively. Overall both files visited on female flowers faster than male flowers. Both sexes of E. obcuritarsis on male and female flowers were different fly foraging rates. While C. megacephala on average both sexes visited female flowers than male flowers with similar foraging rates.

 Keywords: fly pollinators, Diptera, Dipteran, Jatropha curcas L., physic nuts, diversity