Spilomyia crandalli
Curran, 1951
Crandall's Hornet Fly
Spilomyia crandalli is a rare of syrphid fly described by Curran in 1951. are known as flower flies and are commonly found on flowers, where they feed on nectar and pollen. The species belongs to a renowned for exceptional mimicry, including visual, behavioral, and acoustic deception of yellowjackets. Larvae are adapted to moist environments such as tree rot holes.
Pronunciation
How to pronounce Spilomyia crandalli: /ˌspaɪloʊˈmaɪ.ə krænˈdælaɪ/
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Identification
Distinguished from actual yellowjackets (Vespula, Dolichovespula) by short with versus long, thick antennae; single pair of wings versus two pairs; and large meeting at top of . Distinguished from other Spilomyia by geographic range and specific pattern details requiring expert examination. Members of Spilomyia wave their front legs to simulate wasp antennae, a behavioral cue useful for field identification.
Habitat
frequent flowers in various settings. Larvae inhabit moist microhabitats, specifically water-filled rot holes in trees.
Distribution
Documented from Arizona and New Mexico in the United States, and from Mexico. Described as occurring in western North America near the Pacific coast, though specific collection records are sparse.
Diet
feed on nectar and pollen from flowers. Larval diet consists of decaying organic matter in moist tree holes.
Life Cycle
Larvae are described as 'short-tailed larvae' adapted for moist environments such as rot holes in trees. Complete with , larval, pupal, and stages; specific developmental details are not documented.
Behavior
hover in with wingbeat frequency nearly identical to that of yellowjacket , contributing to acoustic mimicry. When at rest, individuals may wave their front legs in front of the to simulate the longer of wasps. The combination of visual, behavioral, and acoustic mimicry creates a multilayered defensive deception.
Ecological Role
function as when visiting flowers. Larvae serve as decomposers and nutrient cyclers in tree rot hole microhabitats.
Human Relevance
Contributes to pollination in natural and potentially agricultural systems. The ' rarity and limited distribution may make it of interest for conservation monitoring.
Similar Taxa
- Spilomyia longicornisAnother North American Spilomyia with similar -mimicking appearance; distinguished by distribution and subtle morphological differences
- Vespula pensylvanica (Western Yellowjacket)Primary model for mimicry; distinguished by two pairs of wings, long thick , and different structure
- Dolichovespula arenaria (Aerial Yellowjacket)Another model for mimicry; distinguished by wing venation, structure, and smaller that do not meet dorsally
More Details
Taxonomic history
Described by Charles Howard Curran in 1951. The specific epithet honors an individual with the surname Crandall.
Mimicry sophistication
The Spilomyia is considered among the most accomplished mimics in the insect world, employing visual (color pattern, markings, wing darkening), behavioral (-waving), and acoustic (wingbeat frequency) components of deception.