Potter Flower-bee (Anthophora retusa) thriving at Seaford Head in areas managed by Sussex Wildlife Trust

Posted by Graeme Lyons , Saturday 12 May 2018 16:55

Last week I started a survey of the rare Potter Flower-bee Anthophora retusa at Seaford Head. Coincidentally, there is also a PhD study being carried out by Gigi Hennessy so we joined forces to get a more thorough idea of where the bee is on the site. As Gigi has some transects concentrated on the key areas, I was keen to have a look at areas away from these transects.

My approach was to GPS every individual found and map them. I also wanted to sex them and record what they were feeding on. That last was easy, all 12 we saw were feeding on Ground-ivy. The problem with recording retusa is the abundance of plumipes still present. The first we recorded last Thursday was a female at the top of the west ride. This is great news as this was just solid scrub only five years ago. This fantastic ride created by SWT and the volunteers has produced plentiful forage for this rare bee. We also saw another male there. Now the female is a little smaller (although this isn't enough to clinch ID in the field - some plumipes are smaller) so you have to catch them and look for the red spines present on the hind leg. This is a bit of a faff. You can see them clearly in the image below but that's after catching the bee and getting it into this cage or small glass tube. The females are faster than the males too.

I went on to catch a male. Much more gingery and lacking the long hairs on the legs of the male plumipes

Here is the habitat showing the wealth of Ground-ivy.

We caught a male plumipes and put it next to the retusa. That's when it hit us, retusa has green eyes just like Anthophora bimaculata while plumipes are black. Actually this is so much easier than trying to see the red spines in the female!

We then went a walk along the coastal grassland where the Anthophora petered out as the Ground-ivy stopped. We saw clouds of very worn male Andrena haemorrhoa flying around the edge of the cliffs. A single Ophonus ardosiacus ran across the cliff top grassland, a new carabid for the site. Dingy and Grizzled Skippers were everywhere. There were however, no Anthophora at all on the golf course side. All but Alex and I headed off and despite a cool westerly breeze, we decided to head to the one other suitable area that Gigi is not covering; the cattle grazed area to the east of Hope Bottom...

The first retusa we had was a female which made for the photo at the top of this post and this video.

We caught a further six males but also three Bombus humilis! I was quite pleased with this, especially as Alex spotted the first one and we didn't see any humilis up there during a thorough survey two years ago. We may have also seen a Bombus ruderaius but we bungled it and the wind took it.

Here you can see a distribution map of what we recorded on Thursday. I will add to this with one more visit in just over a week's time and hopefully we can put all the data together and make this a really useful exercise. Interesting how the two females we recorded were the ones furthest from the coast and the loess they nest in.

Even an Early Purple Orchid has popped up in the grazed area.

So a big thumbs up from me and a male Anthophora plumipes to the work being done there! There is not much we can do about nesting habitat but we can create lots of forage, so thanks to the ride creation, its aftercare and the cattle-grazing and scrub management, we are creating more forage for this incredibly rare bee.

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