Yesterday we had our second Young Naturalists catch up via Zoom, looking once more at the moths in the light trap using the digital microscope and also at some pond creatures I had caught out of the new dipping pond first thing.
We talked about dragonfly and damselfly nymphs and had another look at an exuvia I had found floating in the pond (the dried outer casing left behind when the nymph finishes the aquatic stage of its lifecycle), looked at lesser and greater waterboatmen and a couple of different diving beetles and a diving beetle larva, talked about what materials cased caddisfly larva use to make their cases (the one I caught was thinner and more streamlined than the one in the photo below, living in a tiny tube made of pieces of reed or leaf), talked about the feathery gills on the baby newts or efts which enable them to breathe underwater and are absorbed as they develop, and watched a whirligig beetle whizzing around on the surface of the water – they definitely have the best name out of all the pond creatures!
I didn’t get round to taking any photos of the creatures as a number were trying to escape whilst I was talking about them, so they were swiftly released back into the pond whilst volunteer Nigel chatted through the moths he had caught in his light trap at home. Here are some photos I took a while ago now, it was quite nice to go pond dipping again!
Nigel had also prepared an A to Z of birds quiz which kept the group entertained, especially as not all of the birds were native to this country. Bonus points were also awarded for additional questions about each bird, so I think the group learnt a thing or two, including where Nigel has been on past holidays!
After a very soggy start to the day the sun came out after lunch so I went for a walk around the reserve. In the meadow I was treated to some great views of a female Black-tailed skimmer, who I had disturbed when passing but seemed content to settle again on the grass:
Seeing dragonflies and damselflies at rest is one of the best ways to tell the two apart, dragonflies rest with their wings outstretched, as above, whereas damselflies rest with their wings held together over their abdomen or body:
I also found a Mint moth, Pyrausta purpuralis enjoying the ox-eye daisies. Although the grass and flower stems turned brown very quickly with the absence of rain, the flowers themselves are still blooming.
On my way up to Lapwing Hide I saw what I first thought was a bumblebee, but on closer inspection realised it was a bumblebee hoverfly.
This hoverfly is an excellent bumblebee mimic. There are two main varieties, Volucella bombylans var. plumata seen above has yellow bands and a white tail, mimicking the Garden, White-tailed and Buff-tailed bumblebees whilst Volucella bombylans var. bombylans is black with a red tail, mimicking the Red-tailed bumblebee.
Mimicry reduces the chances of the fly being predated because it resembles a bee. In addition, the females lays their eggs in the nests of bumblebees and wasps where the larvae feed on the nest debris and occasionally the bee larvae as well.
On my way back to the Education Centre I was lucky enough to spot another female Black-tailed skimmer, who also posed beautifully so I could take a really good look and take some more photos:
Dragonflies have amazing vision, which they use to locate and catch insects whilst on the wing. Like most insects they have have compound eyes: each eye contains several thousand individual facets, with each facet containing a tiny lens. Combining all the images from each lens makes their sight better than most other insects.
Their eyes are holoptic, which means they meet along the middle of the head and take up most of it, wrapping around the head from the side to the front of the face. In comparison a damselflies eyes are also large, but they do not meet and there is always space between them. This is known as dichoptic and can be seen on the Banded demoiselle below: