Dilophus stigmaterus
Say, 1823
March fly
Dilophus stigmaterus is a of march fly in the Bibionidae, first described by Thomas Say in 1823. Like other members of the Dilophus, it is typically smaller and less robust than related Bibio species, often with reddish coloration. The genus is distinguished from Bibio by having a ring of shorter teeth on the front legs rather than long spurs. emerge in spring and males form swarms to attract females. Larvae develop in soil and feed on decaying organic matter.
Pronunciation
How to pronounce Dilophus stigmaterus: /dɪˈloʊfəs stɪɡˈmeɪtərəs/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
Distinguished from the similar Bibio by the presence of a ring of shorter teeth on the front tibia instead of long, downcurved spurs. Dilophus are generally smaller and less robust 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 genitalia.
Appearance
are typically smaller and less robust 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 teeth on the front tibia rather than the long, downcurved spurs seen in Bibio. Body length ranges roughly 6-12 mm for the genus.
Habitat
Larvae develop in rich soils, feeding on decaying organic 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
Larvae feed on decaying plant material, manure, compost, and occasionally on roots of grasses and herbs. feeding habits are not documented.
Life Cycle
Females use their toothed front legs to dig into soil several inches deep and deposit in masses of 200-300. Larvae develop in soil, feeding on decaying organic 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 bibionid . are , with reduced activity in late afternoon and evening.
Ecological Role
Larvae function as decomposers, breaking down decaying plant material and organic matter in soils. This contributes to nutrient cycling and soil health. Occasional feeding on roots may cause minor plant damage, but significant pest status is not documented for this .
Human Relevance
Similar Taxa
- BibioSimilar body form and , but distinguished by long downcurved spurs on front tibia (vs. ring of short teeth in Dilophus), larger and more robust 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.