Monday, 4 January 2010

Red-heads

A braconid wasp that is obviously a member of the "Red-head Mimicry Ring".
This mirid bug seems to be a member of the group. But to see a similar but different complex check p. 19 of the reference below.

If you look a the Love Bug flies in the blog below and then have a look at the photos presented here you'll quickly see that there is some similarity among them. They are from completely unrelated families of insects but they share the bright orange thorax. These insects are part of a Mullerian Mimicry Ring. They are part of an intricate advertising program. We may only be seeing a few examples of this group. There may be other insects, and even other invertebrates that share the dark black body and the orange thorax over the larger geographic range of the species involved. At least one species provides a "model" and the model has some feature that is distasteful or dangerous to vertebrate predators. Usually this is a toxic secretion that would either make the lizard or bird sick or at least have an unpleasant experience. Once the predator has had the experience, it learns to recognise the colour, pattern and posture of the model and avoids it and similar-looking creatures. Thus other perfectly edible creatures have evolved similar colours and patterns and are themselves "protected". Of course, there has to be a balance maintained in that the model must be more common than the mimics, otherwise the cover would be blown.

From the way the Love Bugs spend the day on the vegetation unmolested, I would suspect they are unpalatable. The little Snellenia moth below is probably quite edible but must gain some protection by being similar to the Love Bug in size and colour pattern. The mirid may be somewhat toxic as many bugs harbours nasty juices that repel predators. This would add to the overall effectiveness of this mimicry ring. The braconid wasp would be a good model in this situation. It possesses a powerful sting that could well incapacitate a small lizard or bird. A similar bug , moth and wasp have been nicely illustrated by Zborowski and Edwards (2007) in their recent book.



Reference
Zborowski, P., Edwards, Ted. 2007. A Guide to Australian Moths. CSIRO Publishing, Collingwood, Vic.

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