THE SOCIAL WASPS (VESPA, VESPULA AND DOLICHOVESPULA, HYMENOPTERA: VESPIDAE) OF SUFFOLK

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THE SOCIAL WASPS (VESPA, VESPULA AND DOLICHOVESPULA, HYMENOPTERA: VESPIDAE) OF SUFFOLK ADRIAN KNOWLES Introduction The social wasps are a familiar component of the British Hymenoptera fauna, but one which most people shun if not actively fear and kill. However, they are fascinating insects with complex social interactions and life cycle as well as providing an excellent pest control service for anyone willing to share their gardens with them. On the whole, they are not actively aggressive, but their occasional tendency to nest in close proximity to our homes sometimes brings them into conflict with ourselves, at which point they are prepared to defend their nest and its environs from perceived intruders.

These are essentially annual species and, with one exception, follow the same lifecycle. In spring, a previously mated queen emerges from hibernation and, after building up her energy reserves, starts to construct a small nest.

The nest cells are protected by a papery dome or encircling ball, which grows as the nest expands in size. The paper is constructed from wood fibres rasped from usually dead wood, including treated timbers in gardens, and worked into a form of papier mache. The queen provisions the first nest cells herself, but these soon hatch into a worker caste that then gradually takes over the chores of collecting food for the developing larvae and maintaining the nest.

The nest cells are usually arranged in layers (Fig. 1). The maximum number of workers depends on the species, but ranges from a few hundred to several thousand strong. Towards the end of the colony’s life, males and new queens emerge from the nest. After mating, the males eventually die but the queens seek out a place to over-winter before starting the cycle once more. As the colony declines, the workers gradually die off, often dispersing and fending

Figure 1. Nest of Dolichovespula media Median Wasp or French Wasp

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for themselves, at which time they can be bothersome at picnics and barbecues, seeking out sweet food to sustain them for a little while longer.

There are currently eleven species of social wasp recognised within the British list, although the two species of Polistes may be no more than vagrants. Polistes dominula is thought to have established a nest in south London in recent years but the longevity of this colony is not known. This small and doubtfully resident genus is therefore not discussed further in this review, leaving nine truly resident species to consider.

The current UK checklist for this group is as follows: Subfamily POLISTINAE POLISTES Latreille, 1802 dominula (Christ, 1791) gallicus (Linnaeus, 1767) Subfamily VESPINAE DOLICHOVESPULA Rohwer, 1916 media (Retzius, 1783) norwegica (Fabricius, 1781) saxonica (Fabricius, 1793) sylvestris (Scopoli, 1763) VESPA Linnaeus, 1758 crabro Linnaeus, 1758

VESPULA Thomson, 1869 austriaca (Panzer, 1799) germanica (Fabricius, 1793) rufa (Linnaeus, 1758) vulgaris (Linnaeus, 1758) The Suffolk Fauna Eight of the nine established species have now been recorded from Suffolk.

Claude Morley (1935) was aware of six of these. The other two species are relatively recent colonists of the UK and were therefore unknown to him.

Morley also refers to the capture of a specimen of Polistes crinitus. This is a globally rare species seemingly largely restricted to the Caribbean. In the 1935 Transactions he notes, “On the 6 September last Mr. Chester Doughty boxed a Wasp that was flying on the window of a bus, travelling through Gorleston streets. It is a neotropical species (Polistes crinitus, Felton) that constructs a paper nest, consisting of a single exposed comb which is attached to walls, posts, window-frames etc. I possess a specimen that was captured on shipboard off El Carmen Island on the south of Mexico Gulf on 3 July 1912....... How the present individual reached Suffolk alive is obscure: possible in a bunch of fruit.’ It is handy that Mr Doughty was seemingly in the habit of carrying insect boxes on his bus trips. The one British species that does not occur in Suffolk is Vespula austriaca, the Cuckoo Wasp. As this name suggests, this species acts as a cuckoo within nests of another social wasp, Vespula rufa. As such, it does

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not have a worker caste, unlike all other British social wasps. Instead, the queens take over the nest of its host, killing the host queen and with the host workers put into service caring for the eggs and larvae of the intruder. In the autumn, only males and queens of V. austriaca emerge from the nest, with very few V. rufa workers remaining. Most recent records of this species come from Scotland and it appears to be a largely northern species in the UK, with virtually no records from southern or central England.

The following species accounts summarise the life histories, distribution and trends of each of the Suffolk species. They are presented in the order of the checklist given above.

Dolichovespula media Median Wasp or French Wasp This is one of the species that had not been recorded within the UK during Morley’s time. It is likely that a mated queen was brought over from the Continent in shipping, although one or more individuals might have been blown across the Channel by strong prevailing winds. The first British specimen was recorded in East Sussex in 1980, with the first nest observed in 1985. Since then, its range has expanded rapidly so that its distribution now extends to Cornwall, Dyfed, Cumbria and County Durham, with a handful of records from southern Scotland. The first Suffolk record was from 1994 at the Center Parcs holiday complex in Elveden in the north-west of the county, Dolichovespula media

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Figure 2. Dolichovespula media Median Wasp or French Wasp

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although it is highly likely that it had found its way undetected into more southerly parts of the county before then.

It often constructs nests suspended from the branches of trees and bushes, thus bringing it into close proximity to garden users. Whilst these nests are often protected from the elements by being cloaked in foliage, they are occasionally constructed in quite open and exposed locations. It is a large wasp, with males and queens being second only to Hornets in size, with the potential to confuse queens with small worker Hornets. Its worker caste can be quite variable in colour, with some individuals being largely black on the abdomen with only narrow bands of yellow (see Cover).

Dolichovespula norwegica Norwegian Wasp This species can be very similar to D. saxonica, with microscopic or genital examination sometimes needed to determine which species is present. It is one of two species with reddish markings usually on the abdomen (Plate 4), making confusion with Vespula rufa also possible at first sight. It is found throughout Britain and Ireland but is seemingly rather sparsely distributed in East Anglia.

In Suffolk it has only been recorded on six occasions and only two of these have been within the last 15 years. This is another “tree wasp�, frequently suspending its nest structure from branches of trees or shrubs, but also Dolichovespula norwegica

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Figure 3. Dolichovespula norwegica Norwegian Wasp.

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occasionally utilising the eaves of buildings. It is no more a “Norwegian� species than is the Brown Rat (Rattus norvegicus), but was doubtless given this name by Fabricius based on the provenance of his first specimen (as is the case with the rat, named by Linnaeus).

Dolichovespula saxonica Saxon Wasp This is the second recent colonist to have established itself within the UK. The first observation was in 1987 from Surrey, with the first nest confirmed in 1991 from Crawley in West Sussex. Its spread across Britain has been more limited thus far, but it is now well recorded from Kent to Dorset and northwards as far as Yorkshire. It remains scarce in East Anglia. Like D. media, its first Suffolk record comes from Center Parcs, Elveden in 1994 and Steven Falk, who recorded it there, saw it most years between 1994 and 2004 whilst conducting survey work for the holiday park managers. However, the only other record comes from a garden in Corton in 1999.

Whilst probably a genuinely scarce wasp in Suffolk this fact surely indicates the lack of regular recording of these insects, despite their abundance, visibility and willingness to come into gardens. However, it has quite small colonies, perhaps numbering only a few hundred individuals, so even where present, it is unlikely to be as abundant as the more common species. It is another aerial nester, forming colonies in the branches of trees, eaves of houses or suspended from the inside of garage roofs.

Dolichovespula saxonica

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Figure 4. Dolichovespula saxonica Saxon Wasp.

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Dolichovespula sylvestris Tree Wasp Despite Morley’s rather brash summary that “The Tree-building Wasp is generally distributed”, more modern records are few and far between.

Despite its name, this species quite often forms nests at or below ground level or in other cavities, such as bird nest boxes, within roof eaves, hollow trees and cavities within walls. Its tendency to nest in the ground may explain its distribution within Breckland and the Sandlings, but these are also the two places that draw Hymenopterists to study the whole fauna, so it may equally be that people have just not looked for it in the relatively unproductive (entomologically speaking)Dolichovespula clay lands in between. sylvestris

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Figure 5. Dolichovespula sylvestris Tree Wasp.

Vespa crabro Hornet This is one of the more widely recorded species in Suffolk, despite it being formerly rather scarce throughout its range in the UK, with something of a resurgence in recent years. Its large size and bold coloration makes it one of the easier species to name although, as has been cautioned above, larger individuals of Dolichovespula media can resemble small Hornet workers.

It often favours ancient woodland, parkland and old hedgerows, where degenerate trees provide hollows within their trunks, which are a favoured nesting place. It will also utilise roof spaces and other cavities.

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Vespa crabro

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Figure 6. Vespa crabro Hornet

Vespula germanica

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Figure 7. Vespula germanica German Wasp

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Vespula germanica German Wasp This is one of the two most common species and one that forms large colonies, with several thousand workers at their peak. The rather thin scatter of records illustrated is more the result of a lack of recording than true scarcity in Suffolk.

Vespula rufa Red Wasp The English name for this uncommon species comes from suffuse red markings on the front abdominal segments. However, care needs to be taken when identifying this species since the Norwegian Wasp also has red markings here (which are usually stronger and better defined).

Morley (1935) described this species as being “not infrequent in marshy places everywhere�, which is a curious summary given its tendency to nest in dry soils such as heathland and chalk grassland. This habitat preference is mirrored by modern records mapped here, with records largely restricted to the lighter soils of Breckland and the coastal Sandlings zone. It is a ground nester, using cavities in grass tussocks, in leaf litter, under debris lying on the ground and in ant hills. More rarely, it also utilises bird nest boxes, decaying tree stumps and holes in walls. This nesting habit would also suggest a preference for well drained, sandy ratherrufa than marshy ground.

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Figure 8. Vespula rufa Red Wasp.

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Vespula vulgaris Common Wasp It is this species, along with the German Wasp, that is responsible for giving this group a bad name. It is extremely common, forms very large colonies and has a sweet tooth, especially in the autumn when flower forage is perhaps drying up and nest tending chores are coming to an end. It nests in a wide variety of locations, including holes in the ground, cavities in trees, in attics and outbuildings and in dense bushes. Its distribution map is a good illustration of the relative amount of effort that has gone into recording the Hymenoptera across the county, with much effort in the Brecks and coastal heaths but rather sparse coverage elsewhere. It is likely to be a ubiquitous species found in almost every parish, and village. vulgaris Vespulatown

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Figure 9. Vespula vulgaris Common Wasp.

Identification Despite being a small group, which might encourage the would-be entomologist to take greater notice of these insects, they require a certain degree of care, close observation and, for one species pair, dissection of the male genitalia to be absolutely certain. Given their familiarity to the general public, it is perhaps a little surprising that there are not more works dedicated to their identification and ecology. Key identification characters are the facial markings, the arrangement of the dark spots and triangles on the

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abdomen and certain hair colours and characteristics. A good identification key is provided by Else (1994), although some comments on distribution are, by now, out of date. The various insect books produced by Michael Chinery give good arrays of pictures but lack the technical detail necessary for absolutely certain identification of all the species.

Acknowledgements The author would like to extend his thanks to Gen Broad of the Suffolk Biodiversity Partnership and Mrs Harris of Sutton for taking the trouble of responding to my request for dead specimens found in order to broaden the record base for this paper. Thanks also to Suffolk Biological Records Centre for producing the distribution maps and to Paul Brock for his excellent photos.

References Else, G. (1994). Identification: Social Wasps, in British Wildlife Vol. 5 No. 5 pp.

304–311.

Morley, C. (1935). The Hymenoptera of Suffolk, Portio Prima. Trans. Suffolk Nat. Soc. 3: 17–52.

Adrian Knowles Jessups Cottage London Road Capel St Mary Ipswich Suffolk IP9 2JR

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P. Brock Plate 4: Male Dolichovespula norwegica Norwegian Wasp. (p. 16).