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Psyche
Volume 2010 (2010), Article ID 851947, 11 pages
http://dx.doi.org/10.1155/2010/851947
Research Article

Floral Resources and Nesting Requirements of the Ground-Nesting Social Bee, Lasioglossum malachurum (Hymenoptera: Halictidae), in a Mediterranean Semiagricultural Landscape

1Dipartimento di Biologia, Sezione di Zoologia e Citologia, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy
2Dipartimento di Scienze della Terra, Università degli Studi di Milano, Via Mangiagalli 34, 20133 Milano, Italy
3Laboratorio di Palinologia e Paleoecologia, Istituto per la Dinamica dei Processi Ambiental, Consiglio Nazionale Ricerche, Piazza della Scienza 1, 20126 Milano, Italy

Received 24 July 2009; Accepted 11 December 2009

Academic Editor: Claus Rasmussen

Copyright © 2010 Carlo Polidori et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In order to adopt correct conservation strike plans to maintain bee pollination activity it is necessary to know the species' resource utilisation and requirements. We investigated the floral resources and the nesting requirements of the eusocial bee Lasioglossum malachurum Kirby at various sites in a Mediterranean landscape. Analysis of bees' pollen loads showed that Compositae was the more exploited family, although interpopulations differences appeared in the pollen types used. From 5 to 7 pollen types were used by bees, but only as few as 1–1.9 per load. Variations of the pollen spectrum through the annual nesting cycle were conspicuous. At all sites, bees nested in horizontal ground areas with high soil hardness, low acidity, and rare superficial stones. On the other side, the exploited soil was variable in soil granulometry (although always high in % of silt or sand) and it was moderately variable in content of organic matter and highly variable in vegetation cover. Creation of ground patches with these characteristics in proximity of both cultivated and natural flowering fields may successfully promote colonization of new areas by this bee.