[Odonata-l] Tattered wings

[Dennis Paulson]

Bob,

There is an extremely strong correlation between tattered wings and  
age. If a dragonfly lives a long time, it's very likely that its  
wings will get increasingly worn and frayed at the edges. I assume  
those Trithemis are getting near the end of their lives. In strongly  
seasonal high latitudes, you see lots of worn wings toward the end of  
the flight season. Is there anything about this time of year in Oman  
that would make you think some species were nearing the end of their  
flight season?

Wings on a younger individual can also get worn and broken from all  
sorts of causes - colliding with the underbrush, fighting with  
another male, a near miss with a predator, probably a struggle with  
large prey, perhaps even when attempting tandem in flight. I don't  
think there has been any attempt to quantify this or to attempt  
correlations, but you should be able to do it with a marked  
population of libellulids in which males are territorial and can be  
seen over a period of days. Just photograph each male to show its  
wings clearly day after day, then examine the photos over the  
lifetime of the individual. However, it may be that a lot of the wear  
happens after the male loses its territoriality and lives out the  
rest of its life.

I have frequently seen dragonflies that seem as agile as ever while  
missing half of one wing. When they are missing most of one wing,  
they usually fly a bit oddly, but I have seen a few such individuals  
that seemed to be able to maintain a normal lifestyle. I haven't seen  
any in worse shape than that. Perhaps missing a front wing isn't as  
serious as missing a hind wing.

I don't recall seeing damselflies with a wing missing, probably  
because that would be very difficult to detect except in groups such  
as lestids that hold their wings out. To check this, I just looked at  
almost 400 digital photos of Archilestes and Lestes of many species  
and found no wings or major parts of wings missing. All teneral and  
immature individuals had intact wings, but some obviously older ones  
had small pieces missing from the wings, usually at or near the tips.  
Wing wear was definitely less evident than in older anisoperans. I  
suspect there are differences in degree of wing wear with species,  
perching and flight habits, and even habitats.

Dennis


On Apr 8, 2007, at 9:29 AM, Bob Reimer wrote:

> I was out at one of my favourite oasis in Oman yesterday and  
> noticed what seemed to be an unusual number of dragonflies with  
> very tattered wings.  I'm assuming this indicates that they are old  
> or they had some encounters with other predators that were  
> unsuccessful.  I'm attaching pictures of a male and female  
> Trithemis annulata which seemed to be the worst for wear.  The  
> female is missing the tip of each wing while the male seems to be  
> missing most of one hind wing.  Neither seemed overly affected in  
> its ability to fly.  The dragonflies were on a tree beside an  
> aqueduct carrying water between two oases.  If you want to check  
> out the area on Google Earth, the coordinates to fly to are  
> 24.50279N 55.97897E
>
> Are there any records for how little of a wing can remain before  
> flight is totally impaired?  Is there any strong correlation  
> between tattered wings and age?
>
> Thanks!!
>
> Bob Reimer
> Al Ain
> United Arab Emirates
> http://www.flickr.com/photos/rwreimer
> <TrithemisAnnulataF.jpg>
> <TrithemisANnulataM.jpg>
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-----
Dennis Paulson
1724 NE 98 St.
Seattle, WA 98115
206-528-1382
dennispaulson at comcast.net



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