WSU Extension


Parasitic Flies
Bee flies 
Tachinid flies 

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Caption: Adult bee fly (Anastoechus sp.) (Bombyliidae)
Photo by: D.G. James
Parasitic Flies : Bee flies
(revision date: 10/11/2018)

Bee flies are as their name suggests bee-like with large, fuzzy bodies and range from ¼ to ¾ inch in wingspan. Despite spear-like mouthparts, they are pollen feeders and harmless. Their larvae however, are predators or parasitoids of a wide variety of mostly soil-dwelling insect immature stages including grasshoppers, beetles, wasps and bees.

Prey or Pest Targeted
  • Aphids, mealybugs, caterpillars, true bugs, beetles, grasshoppers, leafhoppers, spiders, wasps, bees, whiteflies, insect eggs
Attracting and Keeping Natural Enemies & Pollinators in Your Yard
  • Avoid regular use of synthetic, broad-spectrum pesticides. Infrequent use of certain narrow-spectrum pesticides is more compatible with some beneficials but generally the less chemical inputs there are, the greater and more diverse the beneficial insect community will be. Extensive lawns are also not conducive to attracting and retaining a diversity of beneficial insects, mites and spiders. Minimize lawn areas and maximize shrub and bush plantings. Many beneficials reside naturally in riparian and other ‘natural’ areas near to many back yards. Natural dispersion from these refuges ensures that some beneficials will visit back yards but they will not stay unless food, host and shelter resources are available. Native plants have closer affinities with native insects and therefore provide most of these resources. A garden with a good diversity of local native flora in and around back yards, will improve the abundance and diversity of local, beneficial arthropods. Native flora also provides natural overwintering sites for many beneficial insects and it is useful to leave at least a small area of native vegetation undisturbed during fall and winter.
  • Some kinds of beneficial insects (e.g. lady beetles, lacewings, predatory mites) are available for purchase from commercial suppliers. However, benefits from introducing these beneficials are usually limited and short-lived. Upon release, commercially obtained lady beetles and lacewings often disperse and may rapidly leave your backyard despite the presence of prey and suitable nectar resources. Generally, it is more effective and sustainable to create a garden habitat that will be colonized by beneficials naturally.


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Caption: Adult bee fly (Anastoechus sp.) (Bombyliidae)
Photo by: D.G. James