[Odonata-l] Why report hindwing length and not forewing length also?

[Mike May]

Certainly part of the reason is tradition. Once a large body of data is 
available for a particular measurement, the value of that measurement for 
comparative study is enhanced. I suspect, also, that the hindwing may have 
been selected originally because, when a dragonfly is held in the hand with 
the wings pressed together above the back, the hindwing is positioned 
outside the forewing. Although the forces produced by fore- and hindwings in 
flight are certainly somewhat different, I feel pretty confident that had 
nothing to do with the decision.

The forewings are nearly always slightly longer than the hindwings. My 
impression is that the proportionate difference does not vary greatly with 
size, taxon or sex, but I don't know whether this has been investigated 
rigorously. Females do typically have longer wings than males in comparison 
to other measures of body size such as total length or thoracic mass 
(probably because abdominal mass becomes greater in mature females because 
of the mass of eggs), but I don't know that the differences between fore- 
and hindwings is affected by sex. Maybe Roy Beckemeyer can illuminate that 
question a bit more.

Mike May

----- Original Message ----- 
From: <aardila at uoguelph.ca>
To: "Odonata-l" <odonata-l at listhost.ups.edu>
Sent: Wednesday, March 14, 2007 4:28 AM
Subject: [Odonata-l] Why report hindwing length and not forewing length 
also?


> Hello everyone,
>
> I have the books "Dragonflies of North America"(Needham, Westfall ,and
> May, 2000) and "Damselflies of North America" (Westfall and May,
> 1996). These books are excellent. They report the body size lenght,
> abdomen lenght, and hindwing length for every Odonata species in North
> America.
>
> However, I don't understand why the size of the forewings is not
> reported. Is this by convention? What is the history behind this? Why
> were the hindwings and not the forewings chosen? Is there a
> statistically and biologically insignificant difference between the
> forewings and the hindwings within species (and sex) in Odonates? Is
> this selection based on the role of the hindwings in flight? I would
> appreciate any guidance that could help me find an  answer to these
> questions. Thank you.
>
> Alex
>
> -- 
> Alex Ardila-Garcia
> MSc Candidate
> Genomic Diversity Lab
> Dept. Integrative Biology
> University of Guelph
> Guelph (On), Canada
>
>
>
>
>
>
>
>
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