Something you didn't mention is that dragonflies mate by indirect sperm transfer. That's what the tandem flight is about. I recall a paper years ago that showed that males sometimes grab other males in tandem, remove that male's sperm from the pocket on the second abdominal segment, and replace it with their own. A female mating with the pirated males thus gets the "counterfeit" sperm from the initial male. In reference to your comment that dragonflies also prey on each other, here is a link that shows exactly that: https://www.youtube.com/watch?v=RawnujgPqF8. I don't know what species these are, but maybe you do.
Thanks, Walter. Yep, sperm displacement complicates all this in so many wonderful ways:
- whether there might be any cryptic female choice
- whether she lays eggs alone or still in tandem with a male (Sympetrum lay in tandem, perhaps not all Sympetrum species, however)
I've never heard of a male displacing sperm from another male's intromittent organ, however.
In any event, the dragonfly mating system really does complicate sexual selection (but you'll never hear me complaining about it 😀). Rather than complicate it in this post, I will write about it in detail at some point in the future.
Your video is AWESOME! The predator is Epiaeschna heros (Swamp Darner) taking what is probably Anax junius Common Green Darner), although I can't quite rule out Anax amazili Amazon Darner), but I'll keep workin' on it. By the way, they often go first for decapitation like that.
This is a great essay, thanks, so nicely written and accessible while also being very informative. I love dragonflies and damselflies and here in Scotland, they've been the only insects I've seen in good numbers this year, a year of very few insects general.
Bryan, As usual you have presented fascinating, scientific information in a readable, edifying fashion. Thanks, keep up the good work, and see you soon I hope in Maine.
Great article, thanks! I really enjoyed studying sexual selection as a theory early in my career. The dragonflies remind me of learning about the ‘sneak’ strategy used by some fish (from what I recall) in which sexually mature males maintain a juvenile phenotype to get access to females instead of battling the big boys. What’s super interesting is how some of the morphology obviously responds to the heightened hormone exposure (e.g., reproductive organs) but other parts of the body don’t (e.g., cells producing pigment) in these individuals. Nature is so cool 😎
Thanks, Tara. Yes, the rate of this phenotypic change (an overall "hardening" of the newly emerged adult) depends on a few other things: temperature, sunlight, humidity, perhaps food availability. We call it casually a pre-reproductive stage. Typically, after they emerge, males and females alike move away from their natal waters in order to "harden up" more or less unbothered by members of the same species. Exhibiting fairly synchronous emergence, these meadowhawks and darter species can be quite abundant off in the fields and clearings away from the wetlands and ponds.
Thank you for explaining dragonfly details. Since my undergraduate studies of dragonfly flight patterns at a campus pond, I have enjoyed quiet times watching these dragons. Always more to learn.
Something you didn't mention is that dragonflies mate by indirect sperm transfer. That's what the tandem flight is about. I recall a paper years ago that showed that males sometimes grab other males in tandem, remove that male's sperm from the pocket on the second abdominal segment, and replace it with their own. A female mating with the pirated males thus gets the "counterfeit" sperm from the initial male. In reference to your comment that dragonflies also prey on each other, here is a link that shows exactly that: https://www.youtube.com/watch?v=RawnujgPqF8. I don't know what species these are, but maybe you do.
Thanks, Walter. Yep, sperm displacement complicates all this in so many wonderful ways:
- whether there might be any cryptic female choice
- whether she lays eggs alone or still in tandem with a male (Sympetrum lay in tandem, perhaps not all Sympetrum species, however)
I've never heard of a male displacing sperm from another male's intromittent organ, however.
In any event, the dragonfly mating system really does complicate sexual selection (but you'll never hear me complaining about it 😀). Rather than complicate it in this post, I will write about it in detail at some point in the future.
Your video is AWESOME! The predator is Epiaeschna heros (Swamp Darner) taking what is probably Anax junius Common Green Darner), although I can't quite rule out Anax amazili Amazon Darner), but I'll keep workin' on it. By the way, they often go first for decapitation like that.
Thanks again!
This is a great essay, thanks, so nicely written and accessible while also being very informative. I love dragonflies and damselflies and here in Scotland, they've been the only insects I've seen in good numbers this year, a year of very few insects general.
Thanks, Juliet. Three Sympetrum species on the wing in Scotland! Enjoy!
https://www.inaturalist.org/observations?place_id=7382&subview=map&taxon_id=51556&view=species
Thanks for the link, I've always got an eye out for dragonflies near lakes, lochs and ponds.
Bryan, As usual you have presented fascinating, scientific information in a readable, edifying fashion. Thanks, keep up the good work, and see you soon I hope in Maine.
You're my hero, Sallie!
Excellent work thank you!
Thanks for reading, David!
Great article, thanks! I really enjoyed studying sexual selection as a theory early in my career. The dragonflies remind me of learning about the ‘sneak’ strategy used by some fish (from what I recall) in which sexually mature males maintain a juvenile phenotype to get access to females instead of battling the big boys. What’s super interesting is how some of the morphology obviously responds to the heightened hormone exposure (e.g., reproductive organs) but other parts of the body don’t (e.g., cells producing pigment) in these individuals. Nature is so cool 😎
Thanks, Tara. Yes, the rate of this phenotypic change (an overall "hardening" of the newly emerged adult) depends on a few other things: temperature, sunlight, humidity, perhaps food availability. We call it casually a pre-reproductive stage. Typically, after they emerge, males and females alike move away from their natal waters in order to "harden up" more or less unbothered by members of the same species. Exhibiting fairly synchronous emergence, these meadowhawks and darter species can be quite abundant off in the fields and clearings away from the wetlands and ponds.
Getting together- infinite patterns- the shared details uncover even more miraculous stories, keep us awestruck!
Do enjoy those red dragonflies out and about around you now!
very informative and good writing to boot
thank you
Thank you for explaining dragonfly details. Since my undergraduate studies of dragonfly flight patterns at a campus pond, I have enjoyed quiet times watching these dragons. Always more to learn.
A week or so ago i got a photo of 2 red meadowhawks in tandem:
https://www.inaturalist.org/observations/239467445