common name: bee killers
scientific name: Mallophora bomboides (Wiedemann), Mallophora orcina (Wiedemann),
and Mallophora nigra Williston (Insecta: Diptera: Asilidae)
Three large predaceous robber flies of the
genus Mallophora occur in Florida. Mallophora bomboides (Wiedemann) is known as the
"Florida bee killer," M. orcina (Wiedemann) as the "southern bee killer," and M. nigra Williston
as the "black bee killer" (Bromley 1950). Two other species have been recorded from Florida:
M. rex Bromley and M. chrysomela Bromley. Structurally, there is nothing to distinguish them
from M. bomboides (Wiedemann), and they are considered to be color variants of the latter.
Also, M. nigra Williston may be merely a wholly-black color variant of M. bomboides (Cole and
Pritchard 1964).
At least 20 species in seven genera of asilid flies in the southeastern United States prey on
various Hymenoptera, including honey bees (Apis mellifera L.). Of these, M. orcina is the most
prominent, with 80% or more of its diet comprised of honey bees (Bromley 1946). Instances of
economic losses to beekeepers due to the depredations of asilid bee killers are sporadic, but
Florida is one of the few states where such losses have been reported (Bromley 1950).
Mallophora bomboides occurs in the southeastern United States including North Carolina, South
Carolina, Georgia, Florida, Alabama and Mississippi. Florida county records (Florida State
Collection of Arthropods (FSCA)) include Alachua, Clay, Dade, Flagler, Gadsden, Highlands,
Hillsborough, Indian River, Levy, Martin, Nassau, Palm Beach, Pinellas, Polk, Putnam, Taylor,
Volusia; also Duval and Orange (Bromley 1950). Flight time in Florida is from April through
December, though they are most common in late summer.
Mallophora orcina occurs in the eastern U.S. from Florida north to Ohio and west to Missouri
and Arkansas. Florida county records (FSCA) include Alachua, Broward, Clay, Columbia,
Dade, Duval, Liberty, Monroe, Nassau, Okaloosa, Orange, Polk, Santa Rosa, Sarasota, Wakulla;
also Dixie and Pasco (Cole and Pritchard 1964), Columbia and Putnam (Bromley 1950). Flight
time in Florida is from April through August, though they are most common in mid-summer.
Mallophora nigra is uncommon. FSCA county records include only Alachua, Duval, Highlands,
and Volusia. It is apparently even more rare outside of Florida, having been recorded only from
"N.C." (Cole and Pritchard 1960), presumably North Carolina. Flight time in Florida is from
July through September.
Members of this genus in Florida are large, robust flies. The wings are smoky brown and the
body has dense patches of black and yellow or white hairs. Bee killers resemble
bumblebees and carpenter
bees in shape and coloration. They generally mimic all of the five bumblebee species
occurring in Florida (Stange 1992). They make a beelike hum or buzz when flying (Linsley
1960).
M. nigra, M. bomboides, M. orcina
Adults typically occur in open habitats, often in the vicinity of apiaries. They perch on stalks of
weeds or on tips of shrubs from which they launch their attack (Brower et al. 1960). Prey are
primarily social bees and wasps, including honey bees, bumble bees, carpenter bees, Polistes and
Vespa wasps. Honey bees may be particularly suitable as prey because of their slow flight, local
abundance, and appropriate body size (Poulton 1906). Eggs are laid into the soil. Specific
feeding habits of larvae of the species discussed here are unknown, but larvae of other
Mallophora species are ectoparasites on scarabaeid beetle grubs in the soil (Knutson 1972).
1. Abdomen and scutellum wholly black-haired . . . . . Mallophora nigra
1'. Abdomen and scutellum with white or yellow hairs . . . . . 2
2. Basal four or five abdominal tergites densely covered with yellow hairs; and remaining segments
wholly with black hairs; ventrum of abdomen wholly black haired. Average body length about
20 mm . . . . . Mallophora orcina
2'. Basal three abdominal tergites densely covered with yellow hairs, 4th and 5th tergites with black
hairs, and final 2 segments with pale hairs; ventrum of abdomen with yellow hairs. Average
body length about 25 mm . . . . . Mallophora bomboides
- Bromley SW. 1946. Bee-killing Asilidae of the southeastern states (Diptera). Proceedings of
the Entomological Society of Washington 48: 16-17.
- Bromley SW. 1950. Florida Asilidae (Diptera) with description of one new species. Annals of
the Entomological Society of America 43: 227-239.
- Brower LP, Brower JVZ, Westcott PW. 1960. Experimental studies in mimicry. 5. The
reactions of toads (Bufo terrestris) to bumblebees (Bombus americanorum) and their robberfly
mimics (Mallophora bomboides), with a discussion of aggressive mimicry. The American
Naturalist 94: 343-355.
- Cole FR, Pritchard AE. 1964. The genus Mallophora and related asilid genera in North
America (Diptera: Asilidae). University of California Publications in Entomology 36: 43-100.
- Knutson LV. 1972. Pupa of Neomochtherus angustipennis (Hine), with notes on feeding habits
of robber flies and a review of publications on morphology of immature stages (Diptera:
Asilidae). Proceedings of the Biological Society of Washington 85: 163-178.
- Linsley EG. 1960. Ethology of some bee- and wasp-killing robber flies of southeastern Arizona
and western New Mexico (Diptera: Asilidae). University of California Publications in
Entomology 16: 357-381.
- Poulton EB. 1906. Predacious insects and their prey. Transaction of the Entomological Society
of London 1906: 323-409.
- Stange LA. 1992. The bumble bees of Florida (Hymenoptera: Apidae). Florida Department of
Agriculture & Consumer Services, Division of Plant Industry, Gainesville. Entomology Circular
No. 353. 2 p.
Author: G.J. Steck, Florida
Department of Agriculture and Consumer Services, Division of Plant Industry.
Originally published as DPI Entomology Circular 366.
Photographs: Jeffrey Lotz, FDACS-DPI
Project Coordinator: Thomas R. Fasulo, University of Florida
Publication Number: EENY-315
Publication Date: March 2004
Copyright 2004 University of Florida
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