Nest-renovator
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Chalybion californicum
Common Blue Mud-dauber Wasp, Blue Mud Dauber
Chalybion californicum is a solitary mud-dauber wasp with metallic blue coloration, widely distributed across North America. Females are renowned as predators of black widow spiders and other web-building spiders, using specialized hunting tactics including web vibration to lure prey. Unlike most mud-daubers, this species does not construct nests from scratch but instead renovates abandoned mud nests, particularly those of Sceliphron caementarium. The species is not aggressive toward humans and has been introduced to several regions outside its native range.