Lepidoptera Parasites, Parasitoids, and Predators
Grubs came out of my caterpillar, what is going on?
Don Herbison-Evans,
Stella Crossley

Anthela acuta
caterpillar with red parasites.

Female moths lay between a hundred and several thousand eggs, depending on species. If all these matured into adult moths, and these laid more eggs, etc, then after about four years, all the world land masses would be about a metre deep in caterpillars.

In nature: the parasites, parasitoids, and predators of caterpillars stop them from taking over the world.

Hyposidra talaca
caterpillar with a parasite
(Photo: courtesy of Harold McQueen)


Note that 'parasitoids' are parasitic and actually kill their host, whereas 'parasites' just feed off their host but leave it alive.

ants love pupae, in this case a Graphium agamemnon pupa
(Photo: courtesy of Michael Watt, Cairns, Queensland)

The main parasitoids of caterpillars are particular species of viruses, bacteria, fungi, mites, ticks, wasps and flies.

Agrius convolvuli
caterpillar with a parasite: possibly a Sand Fly (CERATOPOGONIDAE)
(Photo: courtesy of Diana Davey, Woolgoolga, New South Wales))

Caterpillars are just as susceptible to disease as we are, and get the equivalents of flu and measles etc. The viruses in the Cypovirus genus, and the bacterium Bacillus thuringiensis are especially fond of attacking caterpillars, and are used as a biological control agents against pest caterpillars.

Cryptoptila immersana
caterpillar carrying green parasites
(Photo: Don Herbison-Evans, Sydney, New South Wales))

The exact relationship of the various species of Lepidoptera with the various parasitic species of mites (Acarina), flies (Diptera), and wasps (Hymenoptera) is often very specific, and is also of great importance in pest control.

Theretra latreillii
caterpillar with cocoons of a number of wasp parasitoids
(Photo: courtesy of Jan MacDonald, Queensland)

If flies and/or wasps emerge from your caterpillar or pupa, you might consider donating them to your local natural history museum or university entomology department. In due course, there will be study programs on what particular parasites attack what particular species, to understand our ecological systems.

two Tachinid fly larvae recently emerged from a moth chrysalis,
one grub having already pupated.
(Photo: courtesy of Peter Street, Gosford, New South Wales)

The flies attacking caterpillars come mainly from the family TACHINIDAE.

dying Brunia replana, caterpillar with cocoons of a number of wasp parasites.

Wasps that attack caterpillars come from a variety of families, including:


  • wasp checking out a caterpillar
    (Photo: courtesy of Michael Watt, Cairns, Queensland)

    When a caterpillar is infected with a parasite or parasitoid, its behaviour changes, just as ours does when we get a cold or a fever. So though normally caterpillars will keep hidden, caterpillars when infected sometimes start wandering aimlessly about. So if you find a caterpillar wandering about, it is probably ill already.

    caterpillar vs Red-back Spider (Latrodectus hasselti)
    (Photo: courtesy of Robin Sharp, Korong Vale, Victoria)


    Predators also control the caterpillar populations,

    spiders love HESPERIIDAE caterpillars
    (Photo: courtesy of Kath Vail, Inner Pocket, New South Wales)

    such as spiders:

    Dasypodia selenophora
    caterpillar vs Victorian Huntsman Spider (Isopedella victorialis, SPARASSIDAE)
    (Photo: courtesy of Wendy Moore, Melbourne)

    and adult wasps which catch caterpillars, paralyse them, and lay eggs on them, so that when the wasp eggs hatch: the wasp larvae have a ready fresh food supply.

    wasps love caterpillars
    (Photo: courtesy of Trevor Jinks, North Burnett, Queensland)

    and various Bugs attack caterpillars, like Shield Bugs (PENTATOMIDAE)

    Doratifera casta
    caterpillar attacked by the Shield Bug Oechalia schellenbergii
    (Photo: courtesy of Jenny Holmes, Great Western, Victoria)

    and Assassin Bugs (REDUVIIDAE)

    a caterpillar stabbed in the head by young Pristhesancus plagipennis,
    (Photo: courtesy of Harold McQueen, Goodna, Queensland)

    and Scorpion Flies (MECOPTERA : BITTACIDAE) :

    caterpillars versus Harpobittacus australis,
    (Photo: courtesy of Ken Thomas, Coree, Australian Capital Territory)

    and of course Praying Mantids (MANTODEA) will happily feed on any life stage of any Lepidoptera:

    Mantodea vs Lepidoptera
    Mycalesis perseus
    butterfly vs Praying Mantis (MANTODEA)
    (Photo: courtesy of Jeevan Jose)

    and so will birds:

    caterpillar vs Australian magpie (Gymnorhina tibicen)
    (Photo: courtesy of Harold McQueen)

    Even plants attack Lepidoptera:

    Acraea terpsicore
    , caught by a Sundew plant (DROSERACEAE)
    (Photo: courtesy of Alexis & Geoff Ward, near Mt Garnet, Queensland)


    Australian Butterflies
    Australian Moths


    (updated 3 February 2013, 3 December 2018, 9 December 2019, 10 September 2020, 19 April 2021)