Thanks John. Coming at it from the viewpoint of the orchid, the behaviour is mentioned in the useful ‘Wildflowers of the Bush Capital’, 1993, Ian Fraser and Margaret McJannett, page 86, in relation to Caladenia tentaculata the Green-comb Spider Orchid, the only Spider Orchid found in Canberra Nature Park. If you want to see it, it seems September would be the time, the ‘peak flowering month’.
So what do these wasps do the rest of the time? Maybe hang out around REAL pheremones? Another thing is hang out around the abundant wild fennel, a great insect attracter. I remember now that I asked about them about 12 months ago and the ever-helpful Steve Holliday then mentioned flower wasps, as he needed to again. This time the group will spring to mind whenever a large blackish wasp hoves into view. (Don’t tell me, there’s bound to be a ‘FALSE flower wasp’) From Feb 2010:
From: John Rawsthorne [
Sent: Thursday, 24 March 2011 6:02 PM
To: 'pete cranston'; 'Geoffrey Dabb';
Cc:
Subject: RE: [canberrabirds] Entomology Corner - bugs and sex
Strange how the world goes around. I heard this very same fascinating story of sex and deception amongst wasps and orchids while chatting with Graham Brown here in Darwin last weekend.
Anyway, Graham has asked me to pass on, regarding Geoffrey’s photos, that “the wasp is almost certainly a species of the 'Lophocheilus' obscurus complex.”
Cheers
John Rawsthorne
From: pete cranston [
Sent: Thursday, 24 March 2011 11:24 AM
To: Geoffrey Dabb;
Subject: [canberrabirds] Entomology Corner - bugs and sex
The insect is indeed a wasp, same order as the bees (Hymenoptera). This one is a male thynnine wasp - it is winged which distinguishes from its flightless female. These wasps are stars of the screen, with extraordinary footage from Western Australia in the BBC / Attenborough series 'Life in the Undergrowth'. They are involved in a sexual deception system involving orchids that are chemical mimics of the female wasps' pheromone lures. Simply put, the wingless female adult thynnine climbs to the top of a plant (often a grass) and emits her perfume to lure in male suitors. After a brief courtship she allows a male to take her on a nuptial flight during which he mates with her (all captured by BBC film unit). But into this straightforward system come many different orchids, which have attained a perfect or close match to the female thynnine's fragrance - hence luring males deceived into expecting a receptive female. The orchids' shapes and colours are passable imitations of a female perched on the top of a grass blade - certainly good enough for the witless male 'victim' . He attempts to copulate with the orchid's deceptive model, whereupon he receives an orchid pollenium stuck on his rear. Not being too bright, the male repeats the sterile performance (termed 'pseudo-copulation') again and again, ensuring at least the orchid is pollinated.
The system is complex - there are many orchids and many species of thynnines (especially in Western Australia, but also locally in ACT), and there is evidence of quite tight association between the component species. And now the male thynnine has another problem - scientists have succeeded in synthesising the chemicals in the phermone mixes, and can lure in the males for study. Amongst those researching this system is Rod Peakall at the Australian National University.
While teaching students in California over the past decade, this tale, and the footage from the BBC would stimulate even the doziest students.
Pete Cranston
At 11:38 24/03/2011, Geoffrey Dabb wrote:
You may be right Paul. Species? (Note patterned wings and strongly segmented abdomen)
-----Original Message-----
From: Paul T.
Sent: Thursday, 24 March 2011 10:14 AM
To:
Subject: Re: [canberrabirds] Entomology Corner
And then the next frame has the bird on the left answering...... "No,
that is the even rarer Rainbow Wasp-eater!" <grin>
Cheers.
Paul T.
Higgins, ACT.
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