Entomology Corner - bugs and sex

[pete cranston <>]

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: 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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