DipteraDiptera – image index Flies Pollinators and Flies The Eyes of Flies Australian Sheep Blowfly (Lucilia cuprina) Australian Drain Fly Balaana Beefly Bat Flies Bee Flies Bee Fly (Anthrax) Ligyra Australiphthiria Chrysomya saffranea Clogmia (Moth Fly) Eristalinus punctulatus Musca Odontomyia (Soldier Flies) Hermetia illucens (Black Soldier Fly) Robber Flies Sarcophaga aurifrons Soldier Fly Syrphids

Member of the insect order Diptera, and part of the group known as “true flies”, the Bat flies are external parasites of bats, who spend most of their lives on bats, feeding on their blood. Found around the world, they belong to the family Nycteribiidae and the family Streblidae. There are hundreds of species of bat fly, some species are found on multiple bat species, whilst others are host specific.

Pictured here is a bat fly that is a parasite of bats, such as flying foxes that are found in Australia, and quite common along the east coast of Australia. They are approximately 1 to 5 mm long (the one pictured here smaller than an apple seed).

Bat Fly, Brisbane QLD © Cindy King
Bat Fly, Brisbane QLD © Cindy King

The bat flies have a flattened, almost spider-like appearance. They do not have eyes, or if they do they are only enable to sense light. It is thought that many use their sense of smell and their setae (hairs) that cover their body to sense their surrounding environment. Whilst many bat flies do not have wings, if they do have wings, they shed them when they find a host. Other species may retain their wings, but rely on their host for getting around and for feeding. The bat flies bear very little resemblance to other Dipterans.

All members of the superfamily Hippoboscoidea, that includes bat flies, give birth to live young. The bat flies give birth to one young at a time.8

Bat Fly, Brisbane QLD © Cindy King
Bat Fly, Brisbane QLD © Cindy King

We certainly welcome any contribution to expand this section on the Bat Flies. You can contact us via Facebook or use our Contact Us page.


  • Scientific classification
  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Subphylum: Hexapoda
  • Class: Insecta
  • Informal: Pterygotes
  • Order: Diptera
  • Suborder: Brachycera
  • Infraorder: Cyclorrhapha
  • Informal: Schizophora
  • Informal: Calyptratae
  • Superfamily: Hippoboscoidea
  • Family: Nycteribiidae
  • Subfamily:
    • Archinycteribiinae Maa, 1975
    • Cyclopodiinae Maa, 1965
    • Nycteribiinae Westwood, 1835

  • Family: Streblidae
  • Subfamily:
    • Ascodipterinae Monticelli, 1898
    • Nycteriboscinae

Footnote & References

  1. Photograph Bat Fly © Cindy King
  2. Many thanks for feedback and ID to members of Amateur Entomology Australia, Facebook group, https://www.facebook.com/groups/476897096018877/
  3. NYCTERIBIIDAE Samouelle, 1819, Bat Flies, Atlas of Living Australia, https://bie.ala.org.au/species/https://biodiversity.org.au/afd/taxa/8dbbdff8-1f81-4f69-83b2-af81a66794d2
  4. Nycteribiid Bat Flies (Family Nycteribiidae), iNaturalist, https://www.inaturalist.org/taxa/347845-Nycteribiidae
  5. Nycteribiidae (Bat Flies), Field Guide to the Insects of Tasmania, https://tasmanianinsectfieldguide.com/hexapoda/insectsoftasmaniadiptera/suborder-brachycera/infraorder-cyclorrhapha/nycteribiidae-bat-flies/
  6. Nycteribiidae, Wikipedia, https://en.wikipedia.org/wiki/Nycteribiidae
  7. Notes on the bat flies (Diptera: Nycteribiidae) of Australian Megachiroptera (Pteropodidae)., Australian Mammalogy, Journal of the Australian Mammal Society, CSIRO Publishing, https://www.publish.csiro.au/AM/AM87023
  8. Wildlife Photographer of the Year: the curious case of parasitic bat flies, by Emily Osterloff, 21 April 2021, Natural History Museum, https://www.nhm.ac.uk/discover/wildlife-photographer-of-the-year-curious-case-of-parasitic-bat-flies.html

DipteraDiptera – image index Flies Pollinators and Flies The Eyes of Flies Australian Sheep Blowfly (Lucilia cuprina) Australian Drain Fly Balaana Beefly Bat Flies Bee Flies Bee Fly (Anthrax) Ligyra Australiphthiria Chrysomya saffranea Clogmia (Moth Fly) Eristalinus punctulatus Musca Odontomyia (Soldier Flies) Hermetia illucens (Black Soldier Fly) Robber Flies Sarcophaga aurifrons Soldier Fly Syrphids

InsectsBees Beetles Blattodea Butterflies Coleoptera Cicada Crabronidae Diptera Dragonflies & Damselflies Formicidae Hemiptera Heteroptera (True Bugs) Mango Planthopper Moths Orthoptera Orthopteroid Processionary Caterpillar Stink Bugs, Shield Bugs and Allies Syrphidae Wasps Water Scorpion (Laccotrephes tristis) Witchetty Grub