06 April, 2019

Update: First study from the British Demoiselle project now published!

During the 2018 flight season, a study of Demoiselles in Great Britain was launched through iNaturalist. The goal of this study, run by researchers at Durham University, was to learn more about how wing colouration changes through time and in different locations in these species by recruiting participants to submit their photographs of Demoiselles.

Overall, over a hundred ‘citizen scientists’ from across the U.K. submitted a total of nearly 500 photographs to the project. So far, the researchers have measured the relative size of male Banded Demoiselles’ wingspots from these photographs.

One interesting result from this study is that there is a change in the average wingspot size over the flight season: males emerging early in the year tend to have smaller wingspots than males that emerge in the peak season. For instance, here is a photograph of a male taken on June 1st:

and here is a photograph of a male taken a few weeks later on June 23rd:

We report these results, along with other details, in a scientific manuscript, now published in the journal Ecography, available to view here.

These findings are only the beginning. In the future, we will develop new methods to extract measurements of female wing colour (e.g., how light or dark they are), in order to test whether female traits might respond evolutionarily to mating competition between species. We also plan to use the methods and findings developed in Britain to serve as a case study for expanding analyses to the entire range of banded and beautiful demoiselles.

To continue building on our analyses, we hope that iNaturalist users, who were an integral part of last flight season’s success, will continue to observe and submit observations of beautiful and banded demoiselles throughout Great Britain.

Posted on 06 April, 2019 09:44 by smokyrubyspot smokyrubyspot | 0 comments | Leave a comment

13 March, 2018

British Demoiselle Project

We are mapping demoiselle wing colouration across Great Britain. The two species in the U.K. are banded demoiselles (Calopteryx splendens) and beautiful demoiselles (C. virgo).

We know that these species' wing colour varies in different areas, but much of the diversity in wing coloration of U.K. demoiselles remains unknown.

That’s where iNaturalist comes in! We are hoping that citizen scientists can help us fill in gaps in our understanding of how wing colouration varies in time (e.g., by visiting a stream with demoiselles a couple of times each year) and in space.

When submitting photos, please include the location and date of the photograph. If you are submitting multiple photographs, please indicate whether there are repeated photographs of the same individual or whether you are submitting multiple different individuals. Finally, any information on the number of individual demoiselle damselflies that you saw where you took the photo would be very helpful.

Four Tips for Photographing Damselflies:

(1) Photograph the damselfly's wings perpendicular to the camera. This way, the entire wing surface is visible in the photo. For example, this:

(photo credit: flickr user novofotoo)

Is better than this:

(photo credit: Clifton Beard)

(2) Get as close as possible to the damselfly. Being closer to the subject yields a better photograph, but be aware that they may flee from humans if they are too close.

(3) Photograph the damselflies in front of a light background, so that their wings contrast with the background.

(4) When possible, photograph the damselflies in the sun. If the subject is in the shade, you may need to increase your ISO (800-1600+ should do the trick), or decrease your aperture (f8-f12 is fine).  Make sure that your shutter speed is greater than 1/60 at the very minimum, but 1/200 or above is best. Using the flash is also an option, however use caution when deploying the flash, as the flash often catches on surrounding foliage and may cause the subject to appear dark.  

Posted on 13 March, 2018 12:07 by smokyrubyspot smokyrubyspot | 4 comments | Leave a comment