Pollination and Herbivore Ecology of an African Dalechampia (Euphorbiaceae): Comparisons with New World Species

Abstract

Dalechampia cf. parvifolia is a common vine in parts of northern Tanzania. It is similar in floral morphology and many apects of pollination ecology to New World species of Dalechampia. The inflorescence "gland" secretes a sticky resin which attracts female Hertades aff. spiniscutis (Hymenoptera: Megachilidae). These bees regularly pollinate the flowers when collecting the resin or pollin. D. cf. parvifolia, like New World species, self-compatible and capable of self-pollination in the absence of pollinators. The leaves and flowers of D. cf. parvifolia are eaten by several generalist insect herbivores and at least two suspected specialists, Neptidopsis aff. ophione and Byblia aff. acheloin (Lepidoptera: Nymphalidae). These two butterfly genera appear to be related to the specialist herbivores on Dalechampia in the New World. This observation, together with other circumstantial information, supports the hypothesis that Dalechampia and its associated specialist butterfly herbivores were dispersed together throughout the neotropics and western paleotropics either by continental drift in the Cretaceous or by migration across higher latitudes in the Tertiary. Subsequent extinctions in Africa and more recent dispersal of certain advanced Dalechampia species (including the ancestor of D. cf. parvifolia) may account for the present geographic patterns of distribution and diversity of Dalechampia and its herbivores.