Dilophus stigmaterus
Say, 1823
March fly
Dilophus stigmaterus is a of in the , first described by Thomas Say in 1823. Like other members of the Dilophus, it is typically smaller and less than related Bibio species, often with reddish coloration. The genus is distinguished from Bibio by having a ring of shorter on the legs rather than long . emerge in spring and males form swarms to attract females. develop in soil and feed on decaying matter.
Pronunciation
How to pronounce Dilophus stigmaterus: /dɪˈloʊfəs stɪɡˈmeɪtərəs/
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Identification
Distinguished from the similar Bibio by the presence of a ring of shorter on the instead of long, downcurved . Dilophus are generally smaller and less than Bibio, and frequently exhibit reddish coloration. Males have ( meeting at the top of the ), while females have disproportionately small heads. Species-level identification within Dilophus requires examination of male .
Appearance
are typically smaller and less than Bibio , with frequent reddish coloration rather than black. Males have large, spherical that meet at the top of the ( condition). Females have relatively tiny heads compared to their body size. The is characterized by a ring of shorter on the rather than the long, downcurved seen in Bibio. Body length ranges roughly 6-12 mm for the genus.
Habitat
develop in rich soils, feeding on decaying matter. are found in open areas where males form swarms near the ground and low vegetation. Associated with grasslands, fields, and other open with suitable soil conditions for larval development.
Distribution
North America; specific range details for D. stigmaterus not documented in available sources, but the Dilophus contains 15-18 north of Mexico.
Seasonality
emerge in spring, with peak activity in April and May in many regions. Mating occurs during this period, with males forming swarms to attract females.
Diet
feed on decaying material, manure, compost, and occasionally on roots of grasses and herbs. feeding habits are not documented.
Life Cycle
Females use their toothed legs to dig into soil several inches deep and in masses of 200-300. develop in soil, feeding on decaying matter. Mature larvae likely overwinter, pupating in early spring. are short-lived, emerging to mate and disperse.
Behavior
Males form swarms near the ground and low vegetation to attract females. Females approach swarms to select mates. Prolonged copulation and post-copulatory guarding by males has been observed in related . are , with reduced activity in late afternoon and evening.
Ecological Role
function as , breaking down decaying material and matter in soils. This contributes to and soil health. Occasional feeding on roots may cause minor plant damage, but significant pest status is not documented for this .
Human Relevance
Not a significant pest. Unlike the related (Plecia), Dilophus do not form massive nuisance . No documented medical or agricultural importance. May occasionally be noticed in spring when males swarm.
Similar Taxa
- BibioSimilar body form and biology, but distinguished by long downcurved on (vs. ring of short in Dilophus), larger and more body, and typically black coloration.
- Plecia nearcticaRelated in same , but distinguished by massive mating swarms, black body with red , and extreme nuisance status in southeastern United States; not reddish in color like many Dilophus.
More Details
Taxonomic history
The Dilophus contains 15-18 in North America north of Mexico. Many former species of Bibio were synonymized when found to vary in leg color, hair , and other variable characters; true species distinctions require male examination.