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Suffolk Natural History, Vol. 48 HYMENOPTERA RECORDER’S REPORT 2012 ADRIAN KNOWLES
Climate impacts Across the spectrum of invertebrate natural history, 2012 will probably go down as one of the worst for many years. After a promising early spring, endless rain and consistently cool weather had a profound impact on many of the spring-flying bees in the county. For example, the mining bee Andrena haemorrhoa is a relatively common and widespread species and is a real harbinger of spring, with its peak of activity during April and May. However, this year few were seen early on, but females were still being seen in late June, exploiting flowers that would not normally be available to it. The cool weather undoubtedly delayed the emergence of this species, and this is likely to be true for many species active in the spring months. One of the most noticeable aspects of the late summer was the lack of social wasps that normally make such a nuisance of themselves during picnics and barbecues. I have hardly seen any all summer. In the spring, newly emerged queens need to found a new nest, but before that they need to build up their strength following their winter fast. This, and the subsequent foraging for food for the first batch of workers, is highly weather dependent, with wet weather making for poor foraging conditions. It is being speculated that, in some parts of the country, bumblebee colonies may have largely missed out the worker caste and more or less gone straight into producing males and new queens, ready to mate and try again next year. Chantry Park Bioblitz It has already been reported in White Admiral that two important discoveries were made during this mass recording event organised by Ipswich Borough Council on 16 June. The mining bee Lasioglossum sexnotatum is a nationally threatened species, currently accorded the UK Red Data Book status RDB1 “Endangered”. However, south-east Suffolk, and Ipswich in particular, seems to be something of a national stronghold for the species. In recent years, it has been recorded from Orford village, Martlesham Heath, Ipswich Golf Club at Purdis Farm and Holywells Park in Ipswich, so it might not be a complete surprise that it turned up at Chantry Park. However, the status of this species remains fragile, with only one of the aforementioned sites with a population that can be easily refound year on year. At Chantry Park, this bee was taken from a horticultural Meadow Crane’sbill in one of the formal gardens close to the house. At Ipswich Golf Club it can be found foraging on some of the ornamental shrubs planted around the club house. These, and other, observations show, firstly, that the bee seems to have a fairly catholic taste when it comes to forage plants (often a limiting factor for rare species) and secondly that ornamental parks and gardens can have an important role to play in the conservation of invertebrates. The other significant find at Chantry Park was the mining bee Andrena fulvago, the first Suffolk record, since 1799. The national distribution of this species suggests that it is, for whatever reason, curiously lacking from East Anglia. However, as the Chantry Park re-discovery illustrates, this may just be down to lack of recording effort rather than a true phenomenon.
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Also of interest in several of the larger, craggy oaks was the arboreal ant Lasius brunneus. This Nationally Scarce species remains scarcely recorded in Suffolk, with the first modern record from King’s Forest in 2003, courtesy of a Dipterists’ forum expedition. Since then, about half a dozen records to the south of Ipswich have cemented this species in our county fauna. Seek and ye MAY find.... Over the last few years I have attempted to visit relatively under-recorded 10 km squares within Suffolk in order to improve the distributional data of species. It is tempting to visit “classic” sites year after year, finding the same species, be they rare or common, and this can lead to an under estimation of the distribution of species. Rarities are sometimes thought to only occur at four to five sites because those four to five sites are regularly visited in order to see if the species are still present. So, in May I visited a number of churchyards in the centre of the county, where there are relatively few records in the arable clay lands. In such a landscape, churchyards often provide the best old grassland sites. On 23 May, Monk Soham churchyard (a likely former haunt of Claude Morley) had vast numbers of the brood-parasite cuckoo-bee Nomada goodeniana cruising low over the ground, with males looking for females and females looking for nests of the mining bee Andrena nigroaenea within which to lay their eggs. Also present here was the mining bee Andrena labiata, the first record for East Suffolk Vice County since 1999. At the nearby Mickfield churchyard I found the nationally threatened (RDB3) mining bee Andrena proxima. Little is known about the nesting habits of this species, but it does seem to avoid sandy soils, unlike the majority of its kind, and three of the six records I have of this species come from the central clay lands of the county. This reinforces the value of “forcing” oneself to look in less rich habitats for important assemblages. Further to the west, at Ousden church, not far from Newmarket, a dead tree trunk yielded the fifth modern record for the small and slender wasp Passaloecus singularis. On 25 July I decided to take a day’s holiday and picked one of the few sunny days to go and record species within map square TL84, for which I have few records. Only a small part of this hectad lies within Suffolk, largely comprising Sudbury with Great Cornard and open countryside towards Acton. Perusal of internet aerial photography identified what looked to be an interesting grassy slope to the north of Great Cornard, so this became the focus of a couple of hours hot and sunny labour. On arrival it was immediately apparent that my aerial diagnosis was correct. It was a flowerrich south-facing slope that looked like it ought to yield a good number of species. As is generally the way with recording Hymenoptera, a good many captures had to be retained for later identification under the microscope but a few of the larger, more distinctive species could be named with confidence in the field. One of these was a female Cerceris quinquefasciata, a Suffolk and UK Biodiversity Action Plan (BAP) species and currently included within the UK Red Data Book (RDB3 “Rare”). In Suffolk, this digger wasp is actually widely if sparsely distributed, with several records from the Brecks, plus
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locations close to Bury St Edmunds, Ipswich and along the coastal Sandlings. It catches quite common weevils as prey for its larvae, safe in underground cells excavated in usually quite steeply sloping banks. Nevertheless, this was a good record for the south-west of the county. Soon after, a male of the Ruby-tailed Wasp Hedychrum niemelai was taken. This nationally threatened wasp (RDB3) is a brood-parasite on Cerceris nests, with C. quinquefasciata thought to be the most significant host, certainly in Essex (Peter Harvey, pers. comm.) and Suffolk (pers. obs.). Its presence alongside its main host is a good sign that indicates a breeding population of C. quinquefasciata is established in the area. However, this interesting find was eclipsed quite emphatically when I got back home and started to go through the collected material, for here was a single female of its sibling species Cerceris quadricincta. This is also a UK BAP species but its Red Data Book status is RDB1 “Endangered”. Historically, this species has only been recorded in Essex and Kent, with the environs of Colchester being a long-known locality. All of its current known localities here are threatened by habitat change and disturbance. The 1903 Victoria County history of Essex notes that this is not a new phenomenon, stating that it is “mainly an urban insect, for it forms its burrows in the public streets where, owing to alterations, two colonies have been destroyed recently”. These were the days before tar macadam! In Kent it has been recorded in recent years from a number of allotments and also coastal cliffs near Ramsgate. For Suffolk, this specimen becomes the first authenticated record of the species in the county and, nationally, the third county in which this very rare wasp has been recorded. Datasets do show a 1983 record for this species from old pits at Red Lodge near Herringswell, attributed to the late Gerald Dicker. However, this record is something of an enigma, with no known specimen and no field notes to back up this apparent record (Geoff Allen, pers. comm.). Gerald Dicker was an accomplished Hymenopterist and was familiar with this species from localities in Kent, so misidentification can be ruled out with reasonable certainty. The habitat at the site still looks suitable for C. quadricincta and C. quinquefasciata still occurs there in good numbers but, despite repeated visits by numerous Hymenopterists in recent years, no specimens of this species have been found here. The discovery, then, of this most threatened wasp close to Sudbury raises various questions. Has it been in the area all the time, just waiting to be discovered? Has it recently colonised the county? It seems quite inconceivable that this is still the only locality for this wasp in the county. What are the chances of discovery at a single site, based on the whim of one of the very few regular Hymenoptera recorders in Suffolk to go to just the right site at the right time of year? Its historical association with old suburban Colchester may mean that it is, or was, associated with similar habitats in and around Sudbury and this will be the focus of survey activity during 2013. This Great Cornard site yielded several other locally or nationally interesting species, including Heriades truncorum. The arrival of this small, stocky, black bee in Suffolk was reported in Suffolk Natural History Volume 45 (2009). It has now been recorded from three sites in south Suffolk, and has
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also reached southern Norfolk (East Harling; Tim Strudwick, pers. comm.), so the spread of this formerly very rare species appears to be continuing. It is surely to be found in many more locations across Suffolk, awaiting the diligent searcher. It quite probably no longer merits its national threat status of RDB2. Other species of interest include a suite of bees that probably no longer deserve their Nationally Scarce statuses. Hylaeus cornutus (Na) and H. signatus (Nb) are both “yellow-faced bees”, although H. cornutus actually has an all black face. This group of bees is unusual in that the females carry their pollen load mixed with nectar in their gut (crop), regurgitating it within the nest cell, rather than carrying dry pollen packed into hairs on their bodies. The mining bee Lasioglossum pauxillum (Na) probably no longer merits any national scarcity status, it being one of several species that have become distinctly more common over the last 20 years. It’s an ill wind… On 25 July, family responsibilities behoved me to visit my great uncle in Ipswich hospital. Driving to his house beforehand, I was struck by the open parkland and acid grassland of Broom Hill along Valley Road in Ipswich. This was a route not familiar to me, and I resolved to pop in on the way home after my duties had been dispensed. This paid dividends with several interesting finds. The most notable appears to be a new Vice County record of the Nationally Scarce (Nb) red ant Myrmica schencki. I have encountered this ant only once before in Suffolk, from the disused railway line walk near Hadleigh. However, Scott Pedley has recorded it quite widely in Thetford Forest and Kings Forest as part of a University of East Anglia study. Other notable finds include the mining bee Panurgus banksianus (only a handful of recent records in Suffolk), the bee Osmia caerulescens (only third Vice County record) and the digger wasp Ectemnius cephalotes (very thinly scattered across the county). Orford Ness Bioblitz On 4 August, the National Trust organised a Bioblitz event at its Orford Ness property. Despite another blustery day, a few interesting finds were made, the most notable of which was another yellow-faced bee, Hylaeus spilotus (Plate 8). This nationally threatened (RDB1) bee is largely restricted to coastal sites scattered along the south coast, but there are old records for Suffolk (G. Else pers. comm.). This find becomes what would appear to be the only modern east coast record north of the Thames estuary. However, even more than the case of Cerceris quadricincta, it has quite possibly been here all along, waiting to be re-discovered. The blustery conditions prompted a change of tack during parts of the day, seeking out ants in the shingle habitats. Nationally, several scarce species are associated with such coastal habitats and I was not disappointed here. The nationally threatened (RDB3) red ant Myrmica specioides is probably more widespread along the Suffolk coast than is currently apparent from my records. Nationally, it is restricted to the south-east, from the Isle of Wight round to the north Norfolk coast. The red ants are a tricky group,
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relying on subtle differences in the scape of the basal antennal segment and the petiole “nodes” between thorax and abdomen to separate the several species known in the UK. Much of the day was spent examining “ginger” bumblebees. There are three generally ginger-coloured bumblebees in the UK: the ubiquitous Common Carder-bee Bombus pascuorum and two UK BAP species: the Brown-banded Carder-bee Bombus humilis and the Moss Carder-bee Bombus muscorum. These latter two species are very similar and can only be separated for certain by microscopic examination. The desire to do so is tempered by the fact that both of these species have very few populations in Suffolk. In the end, two specimens were taken, one of which looked good for humilis, whilst the other looked more like muscorum. Under the microscope they both look like muscorum! Another find was the very small, black ant Tetramorium caespitum. This is reasonably well scattered along the coastal zone, including inland heaths along the Sandlings and there is also a 1995 record for RAF Lakenheath: its only record from the Brecks also surely to be found there in greater numbers. There’s no place like home During a summer when venturing too far from home ran the risk of a change in the weather before one’s destination was reached, the rewards of merely plundering one’s back garden became increasingly attractive. In June, the small-flowered Cotoneaster in my driveway was attracting up to six different species of bumblebee at one time. This included several workers of the Tree Bumblebee Bombus hypnorum but also a rarer visitor in the form of Bombus rupestris. This black and reddish-orange bumblebee is a cuckoo in the nests of the very similar Red-tailed Bumblebee Bombus lapidarius. Whilst its host is one of the more common species in the county, the cuckoo has only four possible 1990 records. Another county rarity recorded from my garden this year was the small mining bee Lasioglossum fulvicorne, this being the fourth modern record for Suffolk. Nationally, it shows an apparent preference for chalk grassland sites, and the bee has been recorded from the chalk around Great Blakenham, but its appearance in Capel St Mary shows that it is by no means restricted to this habitat. The bundle of canes that I have hanging in a plastic pipe sleeve as an artificial nest site are starting to yield some results, with the Red Mason Bee Osmia rufa and one or more leafcutter bees Megachile sp. seen regularly around the canes. Small pieces of cut leaf closing off the hollow canes show that at least one of the leafcutters has nested here. The ability to dismantle this structure and rear out the nest contents in plastic bags brings with it the opportunity to formally identify the species using the canes. It is also a useful way of finding parasites that have attacked the nest, where they, rather than the host, appears in the spring. The results of this will be reported in next year’s Transactions. Adrian Knowles Jessups Cottage, London Road, Capel St Mary, Suffolk IP9 2JR
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S. Falk Plate 8: Yellow-faced bee Hylaeus spilotus found during the Bioblitz at Orfordness. This nationally threatened (RDB1) bee is largely restricted to coastal sites along the south coast (p. 91).