[Odonata-l] Why report hindwing length

[aardila@uoguelph.ca]

Hi Fred,

I would really like to learn more about your method on measuring wing  
surface area. Thank you,

Alex
-- 
Alex Ardila-Garcia
MSc Candidate
Genomic Diversity Lab
Dept. Integrative Biology
University of Guelph
Guelph (On), Canada



Quoting Fred SaintOurs <fred.saintours at comcast.net>:

> Along these lines, several years ago a co-worker and I developed an easy way
> to accurately measure wing area for insects using a flatbed scanner and
> Adobe Photoshop. Area I believe is more useful than length for most
> analytical purposes, particularly for determining wing-loading for flight
> studies. We never published the procedure, but a few people around the world
> have used it successfully. If anyone is interested I can elaborate.
>
> Fred S
>
>
> ----- Original Message -----
> From: <aardila at uoguelph.ca>
> To: "'Odonata-l'" <odonata-l at listhost.ups.edu>; "Ola Fincke"
> <fincke at ou.edu>; "Nick and Ailsa Donnelly" <tdonelly at binghamton.edu>; "'Mike
> May'" <may at aesop.rutgers.edu>
> Cc: <khmo at att.net>
> Sent: Monday, March 19, 2007 12:18 PM
> Subject: Re: [Odonata-l] Why report hindwing length and not forewinglength
> also?
>
>
>> Hi everyone,
>>
>> I have really enjoyed the discussion so far on this subject. I think
>> that there is always going to be experimental error (EE) in this type
>> of measurements even if there is a detailed protocol. Some initial
>> questions to me are: is the current error statistically significant?
>> Do mean values of individuals from a given species measured by
>> different people vary significantly due to EE? I think that from what
>> it has been discussed EE is fairly small (a few milimeters), therefore
>> this may not be significant and as Mike hinted it would take too much
>> time and unnecessary effort to make detailed (not rapid) measurements
>> of every individual. The mean values seem to be fairly close to the
>> mean values that can be calculated from NWM and WM. Therefore, I think
>> that it may not be necessary to develop a detailed protocol to measure
>> wings sizes and body sizes unless it is required for a detailed study
>> in which different people are making measurements with a specific
>> purpose in mind. The current methods seem to be working well.
>>
>> I think that some of the most important question are, what is the
>> biological significance of all these raw data? Does it matter
>> biologically if two people measure the same individual and get
>> measurements that differ in 2mm? Does it matter if we think that a
>> given species have wings mean sizes of 20 or 18mm? I think that it may
>> not matter. I think it may be more important to look at different size
>> ranges and go from there. That is for example, to look at Odonata
>> species that have wings mean values of less that 20mm, 20-40mm, and
>> more than 40 mm, and see if there is anything that these species have
>> in common biologically-translating the raw data to a biological meaning.
>>
>> Then, what about intraspecific variation? That is, body size variation
>> within species. There seem to be a lot of factors that influence body
>> size in insects. I am only starting to get into this literature, but I
>> have read for example that time, temperature and food are usually
>> important factors that account for this variation. Also, latitud and
>> what it has been mentioned in this discussion seasonal variation. I
>> think that seasonal variation encompasses so many factors that there
>> is room for multiple studies, if not done before, as to what are the
>> most important factors that influence body size variation in Odonata.
>> One of them is sex, as Mike mentioned, females tend to be larger than
>> males in Damselflies and that is reported in his book with the range
>> values for body size. But what about other factors such as food?, for
>> example, I wonder if it matters what nymphs eat, Does this have an
>> effect on adult body size? Does it matter if there is absence or
>> presence of some nutrients in the soil or pond where they live?, the
>> same questions apply for temperature and other factors.
>>
>> So, I think that the discrepancy between measurements may be explained
>> and be more important from the biological perspective as oppposed to
>> how measurement are done. The EE seems fairly unsignificant. Also, the
>> mean values don't seem to differ significantly. If they do vary
>> significantly, then we may wonder if the person making the
>> measurements made a mistake, or more interestingly, maybe there is
>> something really exiting going on at that location with those
>> dragon/damsel flies.
>>
>> Alex
>>
>
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