Numbers
6 spp. in our area, ~60 total
(1)Size
~15-25 mm; M. leschenaulti up to 35 mm
Identification
Large, fuzzy, bee-mimicking robber flies. Resemble Laphria, another genus of robbers that mimic bumblebees, but is even hairier and has antennae with a very thin terminal final segment, whereas Laphria has thick antennae.
Range
neotropical group ranging into so. US
(1);
M. orcina occurs in eastern United States (north to MD-IN-KS-AZ);
M. bomboides, in southeast;
M. atra, in Florida;
M. leschenaulti and
M. fautrix, in the southwest and Texas.
Habitat
Open areas, meadows, etc.
Food
Predatory on other insects, including large bees, wasps.
Life Cycle
Eggs are reported by some sources to be laid in ground (see note below). Larvae
reported to be ectoparasites of scarab beetles.
Eggs of M. leschenaulti laid on upright stems but the larva are soil living. Sometimes concentrated in animal pens with dung and decay or in compost heaps.
Note: given that the related genus
Megaphorus lays eggs in a mass on a stem, more research is needed to see if perhaps all, or most,
Mallophora share this habit. In particular,
M. ruficauda is reported to be a
parasitoid of scarab beetles, and the deposition of eggs above ground is thought to aid in dispersal of the larvae and access to hosts (Castelo and Corley, 2004). Quoting from that reference:
M. ruficauda lays eggs in clusters on tall vegetation. Upon
eclosion, pollen-sized larvae fall and parasitize soil-dwelling scarab beetle larvae. We hypothesized that wind dissemination of
M. ruficauda larvae is important in the host-finding process and that females lay eggs at heights that maximize parasitism of its concealed host.
Print References
Castelo M.K., Corley J.C. (2004) Oviposition behavior in the robber fly
Mallophora ruficauda (Diptera: Asilidae). Ann. Ent. Soc. Am. 97: 1050-1054 (
abstract).
