Eulonchus tristis
Loew, 1872
small-headed fly
Eulonchus tristis is a ( ) to western North America. are known flower visitors, particularly of Brodiaea elegans and Iris douglasiana in California, where they carry substantial pollen loads. The has been documented as a potential , especially for B. elegans. Like other acrocerids, are of .
Identification
Members of are recognized by their small , hump-backed , and reduced mouthparts. Eulonchus tristis can be distinguished from other western North acrocerids by its dark coloration and specific patterns, though detailed diagnostic features require examination.
Habitat
Flower-visiting in California, specifically associated with Brodiaea elegans and Iris douglasiana . The occurs in open habitats where these plants grow.
Distribution
Western North America; documented in California, USA and Washington state, USA.
Diet
visit flowers for nectar; specific food sources beyond pollen and nectar are not documented.
Host Associations
- spiders - -level characteristic; are internal of . Specific for E. tristis not documented in available sources.
Life Cycle
Females lay numerous scattered across the landscape. First- are highly mobile and actively seek . Upon contact, larvae climb the spider's leg and burrow into the body wall, taking up residence near the and feeding internally. Development continues through larval instars within the host, though specific timing and details for this are not documented.
Behavior
actively visit flowers, particularly Brodiaea elegans and Iris douglasiana. They carry large pollen loads, with individuals visiting B. elegans transporting significantly more pollen grains and higher proportions of pollen (91%) than those visiting I. douglasiana (38%). No difference in pollen load quantity or diversity has been observed between male and female visiting B. elegans.
Ecological Role
Potential , particularly of Brodiaea elegans. The substantial pollen loads and high proportion of pollen carried by flower visitors suggest effective pollen transfer. function as of , contributing to spider .
Similar Taxa
- other AcroceridaeShare the characteristic small and hump-backed . Eulonchus tristis is distinguished by its western North distribution and association with specific flowers, particularly Brodiaea elegans.
- other Diptera flower visitorsMay overlap in flower visitation , but acrocerids are distinguished by their distinctive body shape (small , large ) and are not typical mimics like ().
More Details
Pollination potential
A 2008 study found that E. tristis individuals carried approximately nine different pollen , with visitors to Brodiaea elegans showing particularly high fidelity (91% pollen). This suggests the species may be an important, though previously overlooked, of western North flora.