Bee-Kleptoparasite Interactions, but not Nest Provisioning, Vary Across a Wildland-Urban Gradient in the Colorado Front Range

Disturbances, environmental conditions, and ecosystem structure may influence important biotic interactions within forests, including bee parasitism. Here, we test how disturbances and landscape composition in semi-arid forests affect interactions between the solitary bee Osmia lignaria Say (Hymenoptera: Megachilidae) and the kleptoparasite Tricrania stansburyi Haldeman`(Coleoptera: Meloidae). By releasing bees and monitoring nesting boxes, we quantified kleptoparasitism rates by T. stansburyi, relating kleptoparasitism to O. lignaria provisioning success across forest stands that were a) burned at high severity, b) thinned, or c) unburned and untreated control stands, and spanned a wildland-urban gradient. We found that O. lignaria nest provisioning was not influenced by landscape factors or disturbance type. In contrast, T. stansburyi abundance decreased as local urban cover increased. Tricrania stansburyi abundance also increased with O. lignaria nest provisioning. Our results suggest that kleptoparasites are more influenced by landscape variations than their highly mobile hosts.