[Odonata-l] time for eye colour change - Epitheca princeps

[Dennis Paulson]

Larry,

As Richard Rowe wrote, this eye-color change happens at the time of  
sexual maturation, and I suspect that is the case for odonates in  
general (when there is a change). On the other hand, I have seen  
males of some of the smaller Epitheca of North America apparently in  
sexual patrol flight with red-brown eyes, yet their eyes also change  
to green or greenish or blue at some point, so perhaps sexual  
maturation and eye-color change aren't perfectly linked. I'm guessing  
that in all these species, the eyes will eventually change to the  
fully mature color if they live long enough.

There is surely some variation in the time it takes, but if you had a  
decent sample size, you could come up with an average, at least for a  
given region, and there might not be too much variation. This is  
something we know nothing about for most dragonflies. It is surely a  
matter of some days and possibly as much as a few weeks, but I doubt  
if it would be any more than that. But there's no way we can pin it  
down exactly, certainly not for a species like E. princeps, which  
would be very difficult to mark in large numbers soon after emergence.

Have you checked Corbet's book for information of this sort on other  
species?

Richard, do you have any figures for the New Zealand corduliids?

Dennis


On Jul 30, 2009, at 3:32 PM, Larry de March wrote:

> Hi All
>
> Without success I've been trying to find out how long it takes for a
> male /Epitheca princeps/ to develop green eyes.  Does anyone here  
> know?
>
> Thank you.
>
> Larry
>
> -- 
> Larry de March
> Winnipeg, Manitoba
> Canada

-----
Dennis Paulson
1724 NE 98 St.
Seattle, WA 98115
206-528-1382
dennispaulson at comcast.net



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