Insect visitation rates to wild flowers increase in the presence of arid agriculture in South Sinai, Egypt

Abstract

In temperate and tropical environments agricultural intensification has primarily negative consequences for pollinator conservation. However, in arid environments agriculture is often highly dependent on irrigation and farms can offer higher availability of floral resources than the external environment.This study compares floral visitation rates to wild plants inside and outside 40 agricultural gardens in South Sinai, Egypt. The mean number of flower visitors per plant during a 30 min focal watch was significantly higher inside the gardens than outside, and this was true of orders Diptera, Hymenoptera and Lepidoptera.In total, 23 insect families were recorded inside the garden and 17 outside. The average family richness per plant was significantly higher inside the gardens, with higher rates of family accumulation across focal plants. Pollinating insects (hoverflies, solitary bees and honeybees) all had higher visitation rates inside the gardens.Seed set was assessed for two common pollinator-dependent plants, Stachys aegyptiaca and Alkanna orientalis. Neither species showed a significant difference in the seed set achieved inside and outside of the gardens, but S. aegyptiaca produced a higher number of seeds per plant inside the gardens because plants tended to be larger.In contrast to many other studies, the presence of agriculture appears to increase the abundance and diversity of flower visitors in this under-studied system, with no negative effect on the seed set of two common wild species.