Unexpected Rewards

Several months back, as someone who volunteers at Arne RSPB nature reserve, I was invited to a vols meeting.  The subject of the meeting was to ask if any of us would like to assist in survey work over the RSPB reserves locally and at Arne.  I thought it would be a great opportunity to learn more about the wildlife and the habitats that live within the Poole Harbour basin.  So I agreed to help with  birds, bats, hoverflies, bees, wasps and reptiles, and time passed over the spring and I thought little about it.  Then an e-mail arrived a couple of weeks ago asking if I was still interested with a number of dates to help out.

Well this week I attended a day's training and what a day!  I hadn't given it much thought about what species we would be expected to survey but when I found out two of them would be British 'firsts',  that's if we found them.  Our list had four insects, a wasp, beetle, bee-fly and a damselfly and two rare flowers. 

Our first location was for the two flowers and the wasp, the latter was going to be a first for me. This was a species I had looked for a number of times and on the very heathland I was now crossing and had not found them.  After about ten minutes we stopped at a small area of bare ground and we were shown a few tell tale signs to enable us to recognise what we were looking for.

Excavation spoil like sugar granuals piled just a few centimetre away from the burrow

Though we were in the middle of a hot spell we had a little cloud and there wasn't any sign of any wasps other than the burrows, so we continued on and were shown some rare botany in Yellow Century and Pale Violet. By the time we arrived back to our lunch spot the sun was out and the temperature up. While the rest of our group went into the shade two of us stayed near the wasp site.  I suppose I should say this isn't any common or garden wasp this is Purbeck Mason Wasp Pseudepipoona herrichii.  It is a nationally rare and important species that is only found on the Purbeck heaths in the whole of UK.  The nearest continental population is in Northern Spain, but these may be a different species. It appears that they parasitise on a single species of tortrix moth called Acleris Hyemana.

Purbeck Mason Wasp Pseudepipona herrichii with Acleris Hyemana caterpillar © Nick Hull 

Acleris Hyemana the tortrix moth that the Purbeck Mason Wasp  parasitises © Nick Hull

It took about ten minutes before we spotted the first female flying in and I captured a couple of shots before she disappeared down her burrow.  By the time we had left we had recorded at least four with possibly another and found two more burrows.  Fortunately this isn't the only colony but they are a species that is of conservation concern.  We also found a sand wasp Ammophila pubescens which just happened to be the rarer of the two species of Ammophila that inhabits the Poole basin heathlands.

Sand Wasp - Ammophila pubescenes ©Nick Hull

Our next location was just a few miles away for two species and both I have seen before Southern Damselfly and Mottled Bee-fly.  The latter was picked up within a hundred metres from where we had parked and as we walked towards the mire where we hoped to see the damselfly we had several more. These are more fly like than there smaller relatives which many people have visiting there gardens and do not have the straight proboscis that sticks out front like a small javelin.

Mottled Bee-fly - Thyridanthrax fenestratus ©Nick Hull

The Southern Blue Damselfly was pretty straight forward they have quite specific requirement calcareous water that trickles through the heathland in this case from the Purbeck hills. We saw around six of this delightful damsels and watched a pair in tandem egg laying.

Southern Damselfly Coenagrion mercuriale  Nick Hull

Segment showing dianostic mercury mark

It was then back to the cars and a short drive down the road and out on another piece of heath this time for a Heath Tiger Beetle, another first for me, and once we had walked to the right area of the heath we started to find them, not many but sure enough they were still present and appeared to be doing ok.  We also checked out another area for the Purbeck Mason Wasp but didn't find any, though Kat and I did see a Heath Potter Wasp which is also a recordable species.

Heath Tiger Beetle Cicindela sylvatica © Nick Hull

On our way back to the cars we added a Slow Worm which rounded our day off very nicely.

Big Thank you to Peter from RSPB Arne and Sophie from 'Back from the Brink' team for an excellent day's training and to come away with a 100% success in finding all the species was brilliant.