With the forecast again today for lovely sunshine and temperatures reaching the dizzy heights of 10 degrees celsius, I decided to have a wander around at Nethergong to look for and photograph the gall marks laid into branches overhanging the water by the Willow Emerald Damselfly. With the leaves off the trees making it easier to look, I was able to find many branches showing the tell tale markings left where the female had laid the eggs into the branches. Most were laid on the younger thinner branches on the outside of the trees which I assume are softer for the female's ovipositor to penetrate. I ended up finding gall marks on Alder, Willow, Dogrose and Stinging Nettle and all being well, it looks like it will be another good season for this damselfly. As I write in mid February, it wont be long now until the eggs hatch in March whereby, the young will hopefully fall into the water to start their lives as a nymph. They do have a back up plan though in that should they not fall into the water for any reason, the young prolarvae have a jumping mechanism which will hopefully enable them to reach the water. Nature never ceases to amaze. The nymphs unlike some other species will then grow rapidly and emerge as adults a few months later in July /August. Having photographed most of the life of the Willow Emerald Damselfly except the actual young prolarvae hatching and emerging into the water, I decided to bring home a piece of a willow branch and a stinging nettle stem with eggs in them where I have positioned them over a water tray in the hope of photographing some of this action. Its a long shot but you never know, I will just be happy to see some of the prolarvae and try to photograph them before returning them back to the stream at Nethergong where I found them. On another note, I have finally got round to making up a dragonfly and damselfly flight times chart which can be accessed by clicking on the 'Flight Times' tab at the top of the page. I hope others may find it of some use as I no doubt will.
Willow Emerald Damselfly Ovipositing Sites
Willow Emerald Damselfly 'Gall' Marks
Fabulous Marc, lovely way you do 'Gall'.
ReplyDeleteMany thanks Bob. They have such a fascinating lifecycle. Sure to be colonies out there that are still to be discovered.
DeleteNature never ceases to amaze. Sure doesn't, and neither do you for people like me who don't even know what a gall mark is until you come along to tell and illustrate clearly what's going on, and what's doing it....Great stuff Marc.
ReplyDeleteMany thanks Pete. Their lifecycle is truly amazing and one that continues to amaze me. Many will be totally unaware of what story this Damselfly tells. I will do my best later in the year to tell it.
DeleteFabulous information and photography, Marc. When you show eggs that have been laid at that density, it makes me wonder what percentage will achieve maturity to adult damselflies. One day I hope to see these egg depositories myself. The galls remind me of the type of tribal art where the skin is pierced to leave welts.
ReplyDeleteKeep up the good work, and good luck with catching the prolarvae emergence - - - Richard
Many thanks Richard. Like other species, I assume laying a high number will ensure a good rate will hopefully survive harsh weather, predators etc. Hopefully I might have some prolarvae success, if it it's just seeing them.
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