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| Don's Pond, a hothouse of insect lust and gluttony |
I had an Ad infinitum* afternoon yesterday on an idyllic island in the middle of a water lilly-covered pond.
The entertainment came from watching some very
large parasitic wasps misbehaving.
Literally it was lust in the dust as a swarm of several dozen males pounced and pursued females emerging from burrows in the ground.
Radumeris
tasmaniensis (Saussure, 1855) belongs to the
Scoliidae and is rather large – females to 30 mm long. They have the
interesting habit of burrowing in the ground up to a metre or more in search of
beetle grubs that they paralyze with their sting. An egg is deposited and the
wasp grub that hatches from it proceeds to devour the beetle grub alive.
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| Lust-crazed male wasp pursues uninterested female |
Since these beetle grubs are often pests (e.g.
cane grubs), the wasps are considered ‘good insects’. The males, however, are
pretty bogan, lust-crazed and don't know how to take no for an answer. I was not alone in my purving, though. Also absorbed by all the drama was a flight of very large and hairy bee flies (Bombyliidae).
 |
| Bee fly in flight |
Ligyra
satyrus (Fabricius, 1775) is a very large (53 mm
wingspan) bee fly. The type specimens were collected by Joseph Banks
during the Endeavour voyage and it was one of the first Australian insect species
described. Its grubs somehow find their way deep into the ground where they eat
the wasp grubs that are eating the cane grubs.
 |
| Ligyra satyrus (Fabricius, 1775) in person |
*"So nat'ralists observe, a flea
Hath smaller fleas that on him prey;
And these have smaller fleas to bite 'em.
And so proceeds Ad infinitum."
J. Swift (1733) On Poetry: A Rhapsody
References
Berry JA, Osten T & Emberson R. 2001. Radumeris tasmanniensis (Saussure,
1855), the first record of a scoliid wasp from New Zealand (Hymenoptera,
Scoliidae, Campsomerini). Entomophauna 22(4): 41-48.
Yeates DK, Logan D & Lambkin C. 1999.
Immature stages of the bee fly Ligyra
satyrus (F.) (Diptera: Bombyliidae): A hyperparasitoid of canegrubs
(Coleoptera: Scarabaeidae). Australian Journal of Entomology 38: 300–30.
