Sunday, August 11, 2013

Butterfly dogfight - what happened next .........


The photograph in the previous post shows a female cabbage white butterfly escaping from the attentions of a pursuing male and if you look closely at that picture you can see that she's a well-worn individual with tattered wings.















This was even more apparent when she landed. Damage like this makes you wonder just how much wear-and-tear butterfly wings can sustain before the insect's ability to fly is seriously impaired.



As soon as she landed she returned to the serious business of egg-laying, although in this case her choice of location probably isn't a good one - she is laying her egg on a cabbage flower sepal, which will fall off in a couple of days, soon after the flower is pollinated and fertilised, so unless the egg has hatched by then it will end up on the ground.


Whenever the males harassed her the female cabbage white adopted this posture, with her abdomen raised at almost 90 degrees to her body. This is her signal that she has already mated and isn't available for mating again.
















Here she is again, in her 'mate refusal posture', this time on a nasturtium Tropaeolum majus leaf. 

A large white butterfly has laid a cluster of eggs on this leaf, in the bottom-right of the picture. One way of separately large whites and small (cabbage) whites is that the former lay their eggs in clusters whereas the latter lay their eggs singly and well spaced out on the leaf.



















Male cabbage whites seemed to be confused by females that adopt this tail-up posture. They try to mate but can find no way of doing so; this suitor is laying on his side.




The males are quite relentless in their pursuit of reluctant females, but with no success.


12 comments:

  1. Interesting, Phil. Ladies do find different methods of rejecting the unwanted attentions of over-zealous chaps. Female damselflies and dragonflies adopt a bent abdomen posture to send the signal that they have already mated to deter other males. I'm sure I've read somewhere that this can be independent of whether they have mated. I guess "five minutes' peace" is a universal requirement!

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  2. An interesting piece of animal behaviour explained. And a timely reminder that I should slow down and watch, as well as photograph, these beautiful creatures.

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  3. Excellent post Phil, and great shots.

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  4. We watched something similar today - great to have it explained, and also the difference in egg-laying habits. Thank you.

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  5. Hi Graeme, There has been a lot of research on cabbage white breeding habits, on account of their agricultural pest status. Apparently when they mate for the first time the male also leaves behind an 'anti-aphrodisiac' that deters other males from mating until his sperm has fertilised the eggs. Must of worn off in the case of his specimen .............

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  6. Hi part-time naturalist, it was well worth sacrificing our cabbages to be able to watch the lives of these fascinating insects...

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  7. Thanks Keith, it's a great summer for butterflies, isn't it? Such a contrast to last year......

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  8. Hi Caroline, there are some research papers on the web that contain a lot of info about cabbage white behaviour - some that can only be read as abstracts but a few that can read in their entirety - Googling Obara Pieris rapae returns some .......

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  9. Very interesting photos and information, Phil. I have always wondered how butterflies can fly with tattered wings.

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  10. Hi lotusleaf, I think this one was probably just old and suffering from wear-and-tear but later in the summer many of our butterflies - especially those with eye spots on their wings, show signs of being attacked by birds.

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  11. You captured this behaviour very nicely. I did a similar piece on the green-veined white - and made reference to your blog as well.
    https://rcannon992.com/2017/07/23/butterfly-body-language/
    Best regards,
    Ray Cannon

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  12. Hello Ray, Thank you! Butterfly-watching is a great way to spend a sunny summer afternoon, isn't it?!

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