[Odonata-l] Nehalennia color change

Dennis Paulson dpaulson at ups.edu
Mon May 17 15:39:51 PDT 2004

Hello, all.

I just received the recent issue of the Digest of Japanese 
Odonatological Short Communications from Naoya Ishizawa, a set of 
interesting short articles about Japanese dragonflies translated into 
English by Naoya.

In this issue there is a brief paper Changes of the body colour of 
Nehalennia speciosa by Hirozi Naraoka. He released teneral 
individuals of this species in a cage in his yard with appropriate 
Nehalennia habitat and plenty of small insects to eat, and he 
documented their changes in coloration with age. The longest survival 
of this tiny zygopteran was impressive, 41 days for 2 females and 34 
days for a male.

I was equally impressed by the series of color changes shown by his 
descriptions and a series of photos of both sexes showing each stage. 
Both sexes go through a typical Nehalennia coloration of metallic 
green dorsum, blue abdomen tip, and blue-green to yellow-green eyes. 
But with age, the eyes get darker and darker above, finally changing 
to brown (males) or red-brown (females) above, the females even with 
red-brown postocular spots. The thoracic dorsum changes from metallic 
green to copper in females. Furthermore, in the oldest females, the 
blue at the abdomen tip was replaced by brown. Old females even 
showed some pruinosity on the thoracic dorsum and abdomen tip, 
something I'd never heard of in Nehalennia.

I haven't seen this degree of change (pruinosity or red-brown eyes) 
in North American Nehalennia, and I wonder if anyone else has, or in 
N. speciosa in Europe.

This seems like a very good project to pursue with other species of odonates!

Dennis Paulson, Director                           phone 253-879-3798
Slater Museum of Natural History                 fax 253-879-3352
University of Puget Sound                       e-mail dpaulson at ups.edu
1500 N. Warner, #1088
Tacoma, WA 98416-1088
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.ups.edu/pipermail/odonata-l/attachments/20040517/e25fdb9d/attachment.html

More information about the Odonata-l mailing list