Dragonfly Behaviour

[Coolios!]

Earlier today I saw the first Southern Hawker Dragonfly I have seen at my pond, I identified it as a female.
It was only there for about 10 minutes but while it was there it was flying around and rubbing its lower end on a few rocks by the pond. Was it laying eggs? If not what was it doing???

[King Edward]

Yes, laying eggs. This species usually lays its eggs above the water, which then hatch when the water level rises later in the year.

I'm not sure though what happens if the water doesn't rise and submerge them (e.g. because it's a garden pond with a fixed water level) - do these eggs fail to hatch, or can the larvae hatch out and make their way down into the water?

[Dogghound]

Interesting ive not seen them ovipositing on stone, its usually wood or dead vegetation.

Originally Posted by King Edward

I'm not sure though what happens if the water doesn't rise and submerge them (e.g. because it's a garden pond with a fixed water level) - do these eggs fail to hatch, or can the larvae hatch out and make their way down into the water?

The eggs hatch the following spring so in most cases the water level rises, however as long as the egg is not damaged by frost or does not completely dry out it can survive. The 1st instar is more like a small worm than a nymph and can make its way into the pond, where it moults.

[Coolios!]

I layed its eggs on a few stones that will never become submerged, shall I move the stones somewhere where they will eventually??

[Coolios!]

Please Help!!

[King Edward]

No, don't move the stones.

[RoyW]

There's no point in worrying about submerging the rocks because in all likelihood there weren't actually any eggs laid.

Studies where dragonflies (and damselflies) have been watched making ovipositing movements, and the material that they were apparently ovipositing into has been collected and examined afterwards, have shown that an egg is not always laid with each 'probing' movement.
The chances are that the dragonfly that you saw was 'having a feel round' to see if the spot was suitable for it's eggs, but as it would not have been able to lay eggs into rock it won't have laid any.

When dragonfly eggs hatch what initially emerges is known as a "prolarva". This is pretty much like the first instar larva, but is encased within a membrane, often with its legs held close to the body. If the prolarva emerges out of water it will crawl or thrash about (and by doing so more or less 'jump') until it lands in water. It is only once the prolarva reaches water that the membrane wil split and the prolarva will moult into the next stage.

[Red Robin]

Experts on WAB have suggested that the Dragonfly exuvia ('shed skin' in plain English) in my small pond is that of a Southern Hawker:



The point of me mentioning this is that my man-made wildlife pond has no fluctuations in depth more than about half an inch as I top it up weekly with local river water and rainwater also adds itself. So, somehow, doubtless in the way RoyW says, a Dragonfly laid egg/s in my pond.

[King Edward]

Another point is that this species generally does very well in garden ponds, breeding in even very small ponds like Red Robin's above, so there's no need to make special arrangements for it other than to provide suitable pond habitat for the larvae.

[JohanJ]

Had one emerge in my pond only yesterday and took a pic of it - Emerging Dragonfly | Flickr - Photo Sharing!