Pollination ecology and fruiting behavior of Pavetta indica L. (Rubiaceae), a keystone shrub species in the southern Eastern Ghats forest, Andhra Pradesh, India

Abstract

Pavetta indica is a massive bloomer for a brief period in May. The flowers are hermaphroditic, strikingly protandrous, self and cross-compatible, nectariferous and psychophilous. They possess secondary pollen presentation mechanism as a device to avoid autonomous autogamy but it does not prevent geitonogamy. The fruit set largely occurs through geitonogamy and xenogamy. Butterflies, especially papilionids, pierids, nymphalids, and sphingid hawk moth pollinate the flowers while collecting nectar. Honey bees and blue-banded digger bees feed on pollen and effect only accidental pollination. The nectar is sucrose-rich and contains essential and non-essential amino acids. Birds are seed dispersal agents. Seeds are non-dormant and germinate readily during rainy season but their continued growth and establishment is subject to the availability of soil moisture and nutrients. The plant is not able to populate itself in its natural area. The local uses of different parts of the plant have been found to be affecting its reproductive success and natural regeneration rate. Therefore, regulation of the uses of this plant is recommended for its survival and restoration of its population size in the natural areas due to its role as a keystone species for bees and butterflies during dry season.