Is this the feeding damage of Donacia dentata?

Posted by Graeme Lyons , Saturday, 12 August 2017 08:53

If you want to find invertebrates that specialise in feeding on only one plant, then it's a good idea to look at areas that have LOTS of that plant. So when I was out surveying ditch plants at Amberley Wildbrooks last week, I spotted a lot of Arrowhead in one ditch. Now this is the only place I have ever seen the scarce Donacia dentata and then only ever once. Try as I might I could not find any reed beetles on this particular patch of Arrowhead but I did notice these feeding signs. Now, is this likely to be Donacia dentata and if so, is it enough to make a record?

17/08/2017 UPDATE: Clive Turner via Facebook has confirmed this is the case.

Lots of Anthocomus rufus everywhere at the moment. Even had one on the office door at Southerham, a chalk-grassland site, far away from its wetland habitat!

Amberley has incredibly varied soil types, I was working on the more acidic areas last week. There the sandy ditch-slubbings are a brilliant home for Green Tiger Beetle burrows once consolidated, here at a greater density than I have ever seen before.

Some of the ditches here are looking AMAZING. really wide with a gently sloping shelf-like profile and a messy edge. Full of flowers and insects everywhere!

The one species that I had not seen before was this gall on Nettle caused by the fly Dasineura urticae. Also new to the entire reserve network.

Critically Endangered plant seen at Malling Down after not being recorded for 30 years!

Posted by Graeme Lyons , Monday, 7 August 2017 16:48

During a routine grazing assessment of Malling Down today, I decided to have a quick look for the mythical Red Hemp-nettle that has not been seen there for well over a decade (word of moth from a previous site manager) and it would seem not recorded there since 1987 according to the SxBRC and the reserve spreadsheet. I've looked for it four or five times to no avail. Then today I walked up to an area I thought looked suitable and recorded 17 plants! It really goes to show that persistence is key in natural history. It would have been really easy to give up but I had a hunch this species was still there, ticking along for all these years. Perhaps it's having a good year or in previous years I was maybe too early.

I've only ever seen this plant at Rye Harbour, it's stronghold in the county along with Pevensey Bay and Pagham. What's all the fuss about though? Well this plant is classed as Critically Endangered on the Red List, basically the highest level of assessment you  can get before going extinct. So it's great that this little plant with big flowers has been re-found at Malling Down after all these years, as it's now only known from a few dozen sites according to Plantlife. You can read up on it here. At Malling, the 'natural' (it's an old quarry) creation of chalk scree formed by erosion in the quarry is all that is needed to keep this habitat open, although long-term it will probably need some scrub clearance. Being an annual, it must have been here all along as I don't think it's been lurking in the seed bank.

It's a poor competitor, and likes bare, loose chalky or sandy soil. At Rye Harbour it grows on the vegetated shingle, at Malling, it's at the bottom of a huge quarry, right where I always thought it would be! Why I have not seen it before, I don't know but I suspect I have been looking too early. Here is a shot of the habitat.

We GPS'd 17 plants in all, 13 in one cluster, then three and then a singleton, all quite close together.  As the 1987 area was given only as a six figure grid reference, we now have more detailed records to eight figures of where the plants are growing. Suitable looking habitat further up the slope held no more plants. There is another area in the quarry that would take a bit of getting to that might be worth a look though. Brilliant news!

Other plants new to the reserve today included two Hairy Buttercups growing in the bottom of a damp dew pond and some Pellitory-of-the-wall at the top of the quarry. Walking around the quarry we saw several Galium Carpets. A bit like a Common Carpet but more black and white and with a slightly concave leading edge to the fore-wing.

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