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

[Larry de March]

Thank you Richard and Dennis

I have checked Corbet. I found nothing helpful. 

The reason I'm trying to find this out is that we have the first record 
of E. princeps in Manitoba.  It's a male with brown eyes.  I'm trying to 
get an idea of possible origin, local or via immigration (nearest 
records are about 96 and 174km, though there's a lot of inaccessible 
country in between so who knows where the actual nearest populations 
are?).  I suppose my next question should be how likely are individuals 
of this species to disperse relatively long distances before reaching 
sexual maturity?

Larry

Dennis Paulson wrote:
> 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 <mailto:dennispaulson at comcast.net>
>
>
>

-- 
Larry de March
Winnipeg, Manitoba
Canada