Robber Fly
( Asilidae )


2014-0601-01100108-DIP02070-Asilidae[1139h05s,T,A,laterum]{EXD}-G.jpg

PHOTO COMMENT

IDENTIFICATION
Identification:Asilidae
(Latreille ,1802 )
Common Name:Robber Fly
Life Stage:(A) adult

PHYLOGENY

Phylum:Arthropoda
Class:Insecta
Superorder:Holometabola
Order:Diptera
Suborder:Brachycera
Family:Asilidae
Taxon Code:DIP02070
ITIS/TSN:132394

LOCATION DETAILS
Location Name
Knowland Park, Knowland Park, Oakland
County:Alameda County
ECI Site#:CA01100108

RECOGNITION
Recognition
Size: Medium to large predatory flies, often perching in exposed locations and making short flights after prey. Head: Top of head depressed between eyes, with three ocelli in the depression. Face usually bearded, with prominent mystax (dense moustache of stiff bristles). Body: From very hairy to nearly bare. Typically elongate, with a tapering abdomen. Mouthparts: Modified to inject prey with saliva, similar in both sexes (unlike in blood-sucking flies, such as Tabanidae). Antennae: Three-segmented, third segment elongate and often with terminal style (arista). Legs: Stout and spiny. Remarks: Some are bee/wasp mimics
Description
Size: Medium to large predatory flies, often perching in exposed locations and making short flights after prey. Head: Top of head depressed between eyes, with three ocelli in the depression. Face usually bearded, with prominent mystax (dense moustache of stiff bristles). Body: From very hairy to nearly bare. Typically elongate, with a tapering abdomen. Mouthparts: Modified to inject prey with saliva, similar in both sexes (unlike in blood-sucking flies, such as Tabanidae). Antennae: Three-segmented, third segment elongate and often with terminal style (arista). Legs: Stout and spiny. Remarks: Some are bee/wasp mimics
Body Length
5-30 mm, possibly larger (typically 9-15 mm).
Diversity
7000 described species

BIOLOGY
Robber Flies are aerial predators, often taking on prey much larger than they are, including stinging Hymenoptera, powerful grasshoppers, dragonflies and even other Asilidae.
Food
Predatory on a variety of other insects. The Asilidae attack stabbing prey with a short, strong proboscis. The fly saliva containins neurotoxic and proteolytic enzymes which very rapidly paralyze the victim and soon digest the insides; the fly then sucks the liquefied material through the proboscis.
Habitat
Most diverse in dry, open habitats; larvae usually in soil or decaying wood
Range
Worldwide
Diversity
7000 described species
Active Period
Typically summer
Development
Adults lay eggs in the soil or in plants. A few, such as Mallophora and Megaphorus form an egg mass on a plant stem (see photo here). Larvae often predatory, consuming eggs and larvae of other insects in decaying matter. Typically overwinter as pupa, emerge in spring. Life cycle is 1-3 years.

CREDITS
Photographer
Eddie Dunbar
Insect Sciences Museum of California

References
ITIS.
Wikipedia (https://en.wikipedia.org/wiki/Asilidae)


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