Trade-Off between Foraging Activity and Infestation by Nest Parasites in the Primitively Eusocial BeeHalictus scabiosae

Andrea Lienhard,Ilse Kranner,Lea Mirwald,Thomas Hötzl,Gerald Kastberger

doi:10.1155/2010/707501

Andrea Lienhard, Ilse Kranner + Show 3 more

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https://doi.org/10.1155/2010/707501

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Abstract

Diurnal activities ofHalictus scabiosaebees and their nest parasites (major bee-flies, cuckoo wasps, ichneumon wasps,Sphecodesbees, and velvet ants) were investigated at a study site with 159 nests in Eastern Austria. Foraging activity correlated with ambient temperature only before midday and decreased in the afternoon. The activity of nest-infesting parasites increased during the day and correlated with ambient temperature. The match factorfmbetween the ratios of the foraging activities ofH. scabiosaeand the ratios of aspects of morning temperature was assessed on three consecutive days with different weather. The activity patterns of halictine bees and their nest parasites differed: the parasites exhibited only small time windows in which their activities were synchronised with those of their hosts. The bees exhibited an anticyclic behaviour and collected food in times of low parasite pressure and decreased foraging activity when parasite pressure increased.

Highlights

The way in which animals may alter their foraging behaviour under predator or parasite threat is a large and wellresearched area of behavioural ecology [1, 2]
Marginal costs of foraging include the risk of predation, while the animals are carrying food items to their protective cover [4], and they include the infestation of potential hosts by nest parasites
This paper reports on the principles of trade-off between foraging and the risk of infestation by parasites, using Halictus scabiosae bees, which need to juggle between keeping their nest entrances open to facilitate foraging traffic and closing the entrances in order to reduce parasite impact

Summary

Introduction

The way in which animals may alter their foraging behaviour under predator or parasite threat is a large and wellresearched area of behavioural ecology [1, 2]. Marginal costs of foraging include the risk of predation, while the animals are carrying food items to their protective cover [4], and they include the infestation of potential hosts by nest parasites. The duct widens below the entrance, allowing the bypassing of a forager aside a guard bee, and reaches 20 to 30 cm into the soil. It is ramified by lateral ducts, cells, and emergency outlets. Due to the long flight season from the end of April until October [9, 10], halictine bees have evolved as a polylectic species In the summer, they develop smaller sterile summer females with a low rate of production of males [8]. The queen chases off the other females [9] and lives with her Psyche (a)

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