Spring-swarming
Guides
Bibio siebkei
Bibio siebkei is a Holarctic species of March fly in the family Bibionidae. It occurs across both the Palearctic and Nearctic regions, with synonyms including Bibio labradorensis and Bibio monstri now synonymized with this species. Like other Bibio species, adults are likely to be encountered in spring when males form swarming aggregations. Larval stages develop in soil where they feed on decaying organic matter.