Wednesday, February 19, 2014

A Big Wig in the Moth World: Emperor Moth

Emperor Moth Syntherata sp.
The rains continue to scuttle-by the Gympie Region, so the rainy season so far has been a bust. But outside the relic rainforest regions, the climates in Australia always tend towards drought and flood with years of 'normal' rainfall not all that normal. The last few years have been flood in southeast Queensland, so drought is to be expected sooner or later. Last night, though, it looked like relief was in sight. A heavy cloud cover blew in, the moon disappeared, the humidity rose, and it looked perfect mothing weather until the rains came. The mothing was quite good, but the rains never came.
Underside of "Empress" Moth
Most of the moths were still on the small-size, but a handful of the medium-sized fluttered in and two on the large end of the spectrum: an as yet unidentified underwing and this striking Giant Silk Moth (Saturniidae). She is a bit battered, but still rather majestic with a wingspread of 12cm or so. She is a member of the genus Syntherata, either S.  janetta (White, 1843) or the more recently described S. escarlata Lane, Edwards & Naumann, 2010.  Apparently, the females are highly variable and the new species is difficult to separate from the old.
A pair of mystery moths of the micro and macro persuasions
So, although the garden is bone dry, I now have a handful of pictures of mostly attractive and interesting moths to try to identify and learn about. The most difficult are the so-called micro-moths:  a large number of families of small to tiny moths. Identifying them usually requires pinning with the wings spread and dissection of the genitalia. That is too barbaric for me (aka it's too much work), so I will putter around with the more accessible macro-moths. The (~4cm long) macro-moth above maybe in the family Cossidae, but if so it is one of the smaller members of the family that includes the Witchity Grubs. Unknown moths are always more fun, at least up to a point: they are a great excuse to while away the hours looking at pictures of one of life's most colourful groups of animals. 

Reference
Lane DA, Edwards, E.D.; Naumann, S. 2010. A revision of the genus Syntherata Maassen, 1873 (Lepidoptera: Saturniidae) within Australia, with the description of three new species, and description of their life histories. European Entomologist  3(1): 1-41.

Saturday, January 18, 2014

A Naturalist observes that Big Bugs do have Smaller Bugs to bite'm

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.

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.