[leps-talk] MALE x FEMALE emergence

[Neil Jones]

On Monday 20 May 2002 09:51 pm, Nigel Venters wrote:
> Here's a shot at it!
>
> In many species males usually hatch first as their claspers and aedeagus
> need to harden fully before they can mate successfully..often a few
> days...this  allows some dispersion to take place to reduce the chance of
> pairing with a female from their own brood.


I don't think that this is the ultimate reason for males emerging earlier.
When you look at the length of the adult life span ability to harden and mate 
earlier would be likely to be subject to high evolutionary pressures.
It would be unlikely that evolution would deliberately delay mating  
for this reason alone. Even the dispersal argument wouldn't necessarily be 
advantagious. It depends on the size of the population in small populations 
The Allee Effect could even increase the risk of local extinctions. 

The simple explanation as to why males usually hatch first is that they 
develop quicker, being smaller. The larvae pupate earlier and therefore the 
adults emerge earlier.

There are other intincitve mechanisms that work against sibling matings. 
Instictive measures like this are not uncommon. There is one in Homo sapiens.

> Maybe in gregarious species...as there is a high concentration of the same
> brood in exactly the same place...nature by allowing the females to hatch
> first causes an even further dispersion to occur before the males from the
> same brood to hatch, mature and start to pair, thus making it unlikely to
> pair with a sibling. Nigel
>   ----- Original Message -----

--
Neil Jones- Neil at nwjones.demon.co.uk http://www.butterflyguy.com/
NOTE NEW WEB ADDRESS
"At some point I had to stand up and be counted. Who speaks for the
butterflies?" Andrew Lees - The quotation on his memorial at Crymlyn Bog
National Nature Reserve

 
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