I popped up to the woods at Dene Park in the second half of the afternoon, and checked the Black Poplar in the car park and also the three Aspen trees at the junctions along the track for more Poplar Sawfly larvae and also (very hopefully) for the remnants of Hornet Moth pupae protruding from the trunk.
I was successful with finding the Sawfly larvae (Cladius [Trichiocampus] grandis), and there were at least four leaves on the Black Poplar with one to four tiny larvae chewing away at the windowpanes they had created.
I am not very hopeful that they will go to adulthood, as they are reputedly difficult to rear. I wonder how they pupate - they are supposed to each form a chrysalis in a crack in the bark. I should at least go back to check for the "characteristic" egg scars on the petiole - they would be worth photographing! I didn't see any larvae on the Aspen leaves, but Andrew Halstead has apparently found them on Aspen at Wisley.
Note that other sawfly of the Nematus genus do attack Poplars, but in the more conventional Sawfly fashion, usually sitting on the edge of the leaves. The rarer insect I am dealing with here is sometimes called the Hairy Poplar Sawfly to help distinguish it from these other Nematus species.
I didn't find any Hornet Moth pupae, but it could have been very easy to miss them, as I have never seen them before. Of course, it may be that the insect I saw spent its larval stage elsewhere.
It was really nice to see the Lesser Spearwort (Ranunculus flammula) flowering along the middle of the track on the far side of the "square", where the soil, and the shade, is heavier. Where it shares its ground with the Creeping Buttercup, Ranunculus repens, the difference in flower size, colour and shape is fairly obvious. I would describe the Lesser Spearwort as having smaller flowers of a slightly brighter and more acid shiny yellow, with the petals slightly more oval and more separated from each other, giving the flowers as a whole a finer and "classier" look. The sepals soon reflex, and fall early. The flower stem is said to be grooved, which I didn't pick up, but is a good character to separate even larger plants (var. major?) from R. lingua, the Greater Spearwort. In addition the flowers and the individual achenes are smaller, although there is some overlap. I also failed to notice a reputed reddish tinge to the stems, and to be honest I didn't believe this character, even when I went back to check the following day.
When I picked a shoot I hadn't realised that the plant as well as being toxic has an acrid sap that can easily damage skin! An alternative common name is apparently Banewort. It is understood to spread by runners, the stems rooting at the nodes, and that it can potentially form dense clumps, but it has never seemed as aggressive as that to me. It has become naturalised in New Zealand.
I was successful with finding the Sawfly larvae (Cladius [Trichiocampus] grandis), and there were at least four leaves on the Black Poplar with one to four tiny larvae chewing away at the windowpanes they had created.
I am not very hopeful that they will go to adulthood, as they are reputedly difficult to rear. I wonder how they pupate - they are supposed to each form a chrysalis in a crack in the bark. I should at least go back to check for the "characteristic" egg scars on the petiole - they would be worth photographing! I didn't see any larvae on the Aspen leaves, but Andrew Halstead has apparently found them on Aspen at Wisley.
Note that other sawfly of the Nematus genus do attack Poplars, but in the more conventional Sawfly fashion, usually sitting on the edge of the leaves. The rarer insect I am dealing with here is sometimes called the Hairy Poplar Sawfly to help distinguish it from these other Nematus species.
I didn't find any Hornet Moth pupae, but it could have been very easy to miss them, as I have never seen them before. Of course, it may be that the insect I saw spent its larval stage elsewhere.
It was really nice to see the Lesser Spearwort (Ranunculus flammula) flowering along the middle of the track on the far side of the "square", where the soil, and the shade, is heavier. Where it shares its ground with the Creeping Buttercup, Ranunculus repens, the difference in flower size, colour and shape is fairly obvious. I would describe the Lesser Spearwort as having smaller flowers of a slightly brighter and more acid shiny yellow, with the petals slightly more oval and more separated from each other, giving the flowers as a whole a finer and "classier" look. The sepals soon reflex, and fall early. The flower stem is said to be grooved, which I didn't pick up, but is a good character to separate even larger plants (var. major?) from R. lingua, the Greater Spearwort. In addition the flowers and the individual achenes are smaller, although there is some overlap. I also failed to notice a reputed reddish tinge to the stems, and to be honest I didn't believe this character, even when I went back to check the following day.
When I picked a shoot I hadn't realised that the plant as well as being toxic has an acrid sap that can easily damage skin! An alternative common name is apparently Banewort. It is understood to spread by runners, the stems rooting at the nodes, and that it can potentially form dense clumps, but it has never seemed as aggressive as that to me. It has become naturalised in New Zealand.
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