Production and consumption of nectar in flowers of Tasmanian leatherwood, Eucryphia lucida (Eucryphiaceae)

Abstract

The production and consumption of nectar by Eucryphia lucida (Labill.) flowers were studied at two locations in Tasmania. Flowers secreted a relatively dilute nectar (concentration 20% wt/wt). Nectar was produced continuously, although secretion rates were substantially lower at night. At dawn, flowers contained a standing crop of liquid nectar, which was rapidly dehydrated on warm days. Due to continuous daytime production, small amounts of concentrated nectar were always present in flowers; this nectar was highly attractive to insects and flowers received multiple insect visitors. Nectar production was independent of temperature and humidity and was not affected by local shading. Flowers protected from insect visitors and in which nectar was allowed to accumulate showed no evidence of reabsorption of sugar. Patterns of nectar production in E. lucida are interpreted in terms of maximising the frequency of insect visits to flowers in a cool temperate environment in which weather conditions during anthesis can be highly variable.