Insects (Diptera, Hymenoptera) Associated with Minuartia Groenlandica (Caryophyllaceae) on Mount Washington, New Hampshire, U.S.A., and Their Possible Role as Pollinators^*

* Scientific Contribution No. 1099 from the New Hampshire Agricultural Experiment Station.

Abstract

Minuartia groenlandica, an abundant alpine plant inhabiting exposed rocky slopes on Mount Washington, is attractive to at least 15 nectarivorous and pollinivorous insect species, all, except bumblebees, in the Order Diptera. The most common dipterous visitors are Muscidae, Anthomyiidae, and noneristaline Syrphidae not specialized for carrying pollen and therefore having smaller pollen loads on the body than eristaline Syrphidae, and bumblebees possessing specialized pollen retaining bristles. These unspecialized flies may compensate for relatively inefficient pollen transfer by their numerical superiority and by remaining active on cold, cloudy, windy days when specialized pollinators are not active. Abundance and variety of insect visitors to the plant and their ability to function in the rigorous alpine environment unique to Mount Washington ensures cross-pollination. The plant's ubiquity ensures abundant pollen and nectar resources for insects during peak flowering, allowing them to exist in otherwise marginal or inhospitable habitats such as exposed rocky slopes.