Boswellia ovalifoliolata (Burseraceae) is a narrow endemic and endangered deciduous tree species. Its flowering, fruiting and seed dispersal events occur in a leafless state during the dry season. The flowers are small, bisexual, mildly odoriferous and actinomorphic; weakly protandrous but strictly self-incompatible. While insects and sunbirds pollinate the flowers, floral characteristics suggest that entomophily is the principal mode. Both bud and flower feeding by a weevil and flower and fruit feeding by the Palm Squirrel have been found to affect the success of sexual reproduction. The Garden Lizard serves as a predator of pollinating insects, especially bees and wasps, thus influencing pollination of this tree species. Fruit set in open pollination is below 10%, rising to 34% in manual cross-pollination. Limitation of cross-pollination, space constraints for seed production from all flower ovules and availability of limited resources in rocky, dry litter of the forest floor appear to constrain higher fruit set. Mature fruits dehisce and disseminate their lightweight, papery winged seeds with the aid of wind. The study site being windy provides the necessary driving force for effective dispersal of seeds away from parent trees. Seed germination occurs following rainfall but further growth depends on soil water and nutritional status. The success rate of seedling recruitment is highly limited, and it could be due to nutrient-poor soil and water stress resulting from dry spells during the rainy season.

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The current study is based on the screening of novel insecticides from new sources that have not being exploited hitherto. The major objectives of this research work were to extract marine molluscs, Lambis lambis, Trochus radiatus and Chicoreus ramosus, from Tuticorin coastal waters using different solvents to test their insecticidal properties and partially purify the active components. The ethyl acetate extracts of L. lambis and T. radiatus showed 100% mortality of Sitophilus oryzae, at a concentration of 200 μg ml −1 . The LC 50 values for ethyl acetate extracts of L. lambis, T. radiatus and C. ramosus were found to be 67.08, 348.86 and 571.42 μg ml −1 , respectively. With regard to bacterial metabolites, at a concentration of 200 μg ml −1 the ethyl acetate extract of A3 was able to elicit an activity of 40% and that of strain A1 -20%. The LC 50 values of the bacterial metabolites were also investigated. Upon chromatographic separation of active ethyl acetate extracts of T. radiatus, the 100% methanol column-purified fraction was found to have an activity of 30% at a concentration of 10 μg against S. oryzae. The purity of the partially pure active compound was observed to be 72.78% on analysis with high pressure thin layer chromatography.

Citation: Raju, A.J.S., K.V. Ramana & P.H. Chandra (2013). Floral ecology and pollination in Eriolaena lushingtonii (Sterculiaceae), an endemic and threatened deciduous tree species of southern peninsular India. Journal of Threatened Taxa 5(9): 4359-4367; http://dx.doi.org/10.11609/JoTT.o3168. Copyright: © Raju et al. 2013. Creative Commons Attribution 3.0 Unported License. JoTT allows unrestricted use of this article in any medium, reproduction and distribution by providing adequate credit to the authors and the source of publication. Abstract: Eriolaena lushingtonii is an endemic and threatened medium-sized deciduous tree species. The flowering is very brief and occurs during the early wet season. The flowers are solitary, remain within the foliage and attract a few bee foragers only in the presence of nectariferous and polleniferous plants such as Holarrhena pubescens, Grewia tiliaefolia and Orthosiphon rubicundus which are common, exhibit gregarious flowering and attract a wide array of insects. In E. lushingtonii, the floral characteristics suggest entomophily but it is exclusively melittophilous involving Apis, Trigona and Xylocopa bees in the study area. The hermaphroditic flowers with the stigmatose style beyond the height of stamens and the sticky pollen grains do not facilitate autogamy but promote out-crossing. The study showed that pollinator limitation is responsible for the low fruit set but it is, however, compensated by multi-seeded fruits. Anther predation by a beetle also affects the reproductive success. Explosive fruit dehiscence and anemochory are special characteristics but these events are not effective during the wet season. The locals exploit the plant for treating snake bites, scorpion sting, making ropes and fuel wood. Therefore, the pollinator limitation, ineffective anemochory, seedling establishment problems and local uses largely contribute to the endemic and endangered status of E. lushingtonii.

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