A walk through the quarry in glorious June sunshine was enriched by the sight of a Bishop’s Mitre shieldbug stumbling and clambering through the rabbit-cropped turf. This species of shieldbug is one of the easiest to identify from its distinctive shape, yet it has proved elusive in the Country Park until now.
The visit was also fortunate to find a couple of flightless wasps that hunt prey by jumping onto them. This species of wasp Dinocarsis hemiptera was found last year in the rush growing in the seasonal pond of the quarry, but this visit found them in Sheep’s Sorrel growing in the area so well cleared by volunteers in former times.
If you head along the causeway from the visitor centre toward the quarry but turn left before descending the uneven rock cut steps, you will find yourself on the edge of Coastguard Lane Field. There is a very stunted, scrubby little oak by the path that goes unnoticed most of the time, but a very close look into its unfurling leaves has found a new species for the Country Park. Holarcticesa clinius (formerly Grahamis clinius) is a parasitic wasp of the family Eulophidae and subfamily Entedontinae, and is approximately 1.5mm long.
There is a scrubby sallow growing on the seaward side of the hibernaculum in Coastguard Field. Giving it close examination recently discovered a tiny (1.5mm long) parasitic wasp lurking within its branches. It was a Diglyphus isaea, a species that is commercially available as a biological control for several species of leafminer. An adult wasp will seek out the larvae that create leaf mines (in Chrysanthemums for example) and lay eggs in the leaf mining larva. The process will kill the leaf mining larva, and the emerging wasp larva then uses the leaf mining larva as food. While this might sound like a grisly process, it is entirely natural behaviour that has been utilised for commercial benefit. Introduction of such species as Diglyphus isaea into commercial glasshouses gives opportunity for escape into the natural environment, and the one found in Coastguard Field will have originated this way. As to how many generations of parasitoid have passed between the introduction and this discovery can never be known, but it is another new record for the Country Park.
A colourful wasp was recently found in the sallow growing before the exposed rockface at the back of the quarry. It is Microterys seyon, a tiny wasp that is a parasitoid of soft brown scale Coccus hesperidum. Its discovery was a first for this area, and most unexpected.
A sunny autumnal stroll along the clifftop path on the Firehills has produced an interesting result. A Thrips was found within the grass and gorse at the point where the cliff falls away, it is a tiny insect of no more than 2mm length, of the Order Thysanoptera. Examination under the microscope proved it to be a Thrips but further identification needed greater expertise. The Thrips was delivered to Dr. Manfred Ulitzka in Offenburg (the world expert) and he has identified it as a female Odontothrips ulicis. Dr.Ulitzka was very pleased to make this identification as he only has one example of this species in his collection, and his is a male – hence he is delighted to have filled a gap in his collection. The record of this Thrips has been placed, and it is only the sixth UK record at the Biological Records Centre and the first record on the National Biodiversity Network Atlas. The Country Park has done it again.
Removal of blocks of single-age gorse on the Firehills has created significant areas of new habitat, and it is interesting to observe colonisation of this new habitat. The past couple of weeks has seen the cut and removal of two year’s growth, and has left a short stubble of gorse and grass. A survey of this seemingly unwelcoming habitat found a most distinctive wasp. It was one of the parasitic wasps that tend to be parasitoids of gall-forming insects or mites. Identification proved a challenge, but we can now relish the thought that Sympiesis dolichogaster has been found in the Country Park. That might not seem too exciting at first reading, but the only other UK record was on the Isles of Scilly, hence it appears to be the first mainland UK record.
Encountering the Cold War Bunker in the Country Park is often the start of many questions springing to mind. When was it operational, how many service personnel were stationed there, what is its layout, why did they knock down the guardhouse? Are just a few of the typical questions. One of the less frequently asked questions is “what species of wasp could that be?” A walk atop the bunker yesterday brought the discovery of a tiny wasp, less than 2mm long, but very beautiful with its distinctive colouration. Callitula pyrrhogaster is one of the flightless parasitic wasps and there are very few records of its presence. It is said to be a reasonably common species but almost no one bothers to identify this branch of wasps as they are so difficult. As a result this is another first for the Country Park and another first for Sussex.