Sunday, October 10, 2010

Introducing the Sexually Dichromatic Dot-tailed Whiteface

It always amazes me how similar dragonflies are to birds. For instance many dragonflies are sexually dichromatic just like many song birds. What is sexual dichromatism? It simply means that there is a difference in color between males and females of the same species. Like male cardinals are bright red while the female cardinal in more of a yellow color.
If you did not know anything about dragonflies and you looked at the two pictures above you would probably think that you were looking at two different types of dragonflies. However both of the pictured dragonflies are dot-tailed whiteface, a sexually dichromatic member of the skimmer family. The top photo is an example of the dot-tailed whiteface female while the bottom photo is a male. Not all dragonflies are sexually dichromatic, just as all birds are not, but many of the skimmers are.

9 comments:

EG Wow said...

Great shots of these dragonflies!

Rachel Roushey said...

Such great detail on those wings!

Poetic Shutterbug said...

I did not know any of this and am always happy to learn these new things. Wonderful shots of these two.

David, Melanie and family said...

Dot-tailed whiteface...excellent name and excellent camera work!
I just learned some are called dropwings due to the way they hold their wings when resting and these dragonflies are doing just that. Others hold them straight. It's not too scientific, but cool for ID purposes. I have 3 species in our pond area, but didn't know the technical name for the male/female coloration.
Thanks for the insights.
David

LC said...

excellent! L

Maaike said...

a great shot!

tammymcchesney said...

I love dragonflies and you captured these fabulously...what great detail!

Coffeeveggie addict. said...

great shots...
my watery wednesday

centuryplant said...

Nice photos, but the write-up is incorrect. The bottom photo is actually a female Dot-Tailed Whiteface and I am almost certain that the top one is a juvenile male. Both sexes have a row of yellow markings along the abdomen that darken as they age, except for one squarish spot on segment seven. There isn't a major color difference between the sexes in this species, although in females the yellow spots don't always disappear completely.