Pollination ecology ofJatropha gossypiifolia (Euphorbiaceae)

Abstract

Jatropha gossypiifolia is monoecious with a prolonged flowering season. The breeding system incorporates both geitonogamy and xenogamy. The flowers anthese during 0600–0700 hr and offer nectar as the only reward to the insect visitors. Of the 18 species of insect foragers, bees (Trigona sp.,Apis florea, A. cerana indica), wasps (Scolia cruenta. Rhynchium metallicum. Ropalidia spatulata), flies (Sarcophaga orchidea, Rhyncomya viridaurea) and butterflies (Catopsilia crocale) promote both geitonogamous and xenogamous pollinations. The unnel-shaped topography of the blossoms with the centrally-situated androecium/stigma favours nototribic pollen transfer by the smaller bodiedTrigona, and sternotribic and nototribic transfer by the slightly larger-bodied insects. Coevolution is not evident in the partners of the system.Jatropha occurs intermingled with other weedy taxa. Its flower visitors are those normally conditioned on other species, and their composition and abundance depend on the density of forage available at the simultaneously blooming sympatric species and on the extent of competition for that forage. Though a minority species forming a subsidiary resource to the insects,Jatropha is not at a reproductive handicap. Its coexistence is neither harmful nor beneficial to the major plant taxa.