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Individual study: Both native and introduced cavity-nesting bees use drilled wooden nest boxes in riparian oak woodland, Cosumnes River Preserve, California, USA

Published source details

Barthell J.F., Gordon W.F. & Thorp R.W. (1998) Invader effects in a community of cavity nesting Megachilid bees (Hymenoptera: Megachildae). Environmental Entomology, 27, 240-247


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Provide artificial nest sites for solitary bees Bee Conservation

Thirty to 45 drilled pine wood solitary bee nest boxes were suspended from valley oak Quercus lobata trees on the Cosumnes River Preserve, California, USA in 1989 and 1990 (Barthell et al. 1998). The boxes each had twelve 10 cm deep holes, 0.5, 0.65 or 0.8 cm in diameter. In both years, the European earwig Forficula auricularia was the most common occupant (59-85% of all occupied nests), followed by two introduced leafcutter bee species Megachile rotundata and M. apicalis (19.6% of all occupied nests in 1989, 3.4% in 1990). Four native bee species also occupied the boxes, but in much lower numbers. Megachile angelarum was found in 3.2-3.8% of occupied nests. M. fidelis, M. gentilis and Osmia texana occupied less than 1% of occupied nest boxes in both years.