There is no shortage of wasps in woodland, with many making their nests in timber. Those which I have seen and photographed nesting in the garden, including Ancistrocerus nigricornis and Ectemnius cavifrons, are included on that page and on the Bees & Wasps in flight page. Ectemnius rubicola (10mm) is similar to Ectemnius continuus but slightly smaller and less frequent. It is the only member of the genus which nests in plant stems, such as thistles and brambles, rather than dead wood. Ectemnius dives (12mm), another dead wood nester, was a 20th century arrival in Britain and has spread quite effectively.
Argogorytes mystaceus (14mm) prey on spittle-bug (Homoptera sp) nymphs, up to 27 of which are deposited in each cell dug within a 10cm burrow in dry banks in woodland glades. Males have the longest antennae proportionately to their bodies of any Sphecid wasp. A fairly common cuckoo wasp which bears a passing resemblance to Argogorytes mystaceus preys upon that wasp. The cleptoparasite, which lays an egg in one or more cells, is called Nysson spinosus (10mm) and can be seen, albeit not often for any length of time, skulking around the dense vegetation that suits the host for hunting.
Lestiphorus bicinctus (13mm) is a scarce species found in various locations on light soils, including parkland and woodland clearings but also heathland and coastal dunes. They prey on bugs which are placed in a burrow dug in the soil. The equally scarce wasp Nysson trimaculatus (9mm) cleptoparasitises Lestiphorus bicinctus and two other scarce wasps, Gorytes laticinctus, shown in the Heathland section of this website under Sandpits, and Gorytes quadrifasciatus.
There are more than 20 Crossocerus species in Britain and the majority have entirely black abdomens. The chunkiest of these is another wood burrower, Crossocerus megacephalus, which can grow to 10mm or so and catches a wide variety of Diptera as food for its grubs.
The female pictured above was nesting in mid-October 2007, much later than usual for the species, which is usually seen up to the end of August. Uncommonly she was also nesting within a short distance of two Crossocerus pusillus, a sand-burrowing member of the genus, since her burrow was in a remnant root on a root-plate rather than in a stump, log or post.
Other wood-nesting members of the genus include Crossocerus cetratus (7mm), which preys mainly on small Diptera, Crossocerus podagricus (7mm), which also catches Diptera, and Crossocerus congener, a smaller version of Crossocerus podagricus which is scarce throughout its international range. The first UK specimen was found in Hertfordshire in 1999 since when there have been only a handful more found, including the pictured female at Reigate Heath SSSI in Surrey in June 2008.
Three other black wasps are led by Pemphredon rugifera (6mm), which is a Red Data Book species. They have an odd distribution across the UK, with most sightings in eastern Scotland and south-east England. Not that that there have been many sightings anywhere – the female shown here from 2007 was only the third found in Surrey in the last 60 years. The Scottish connection has led to the suggestion that Pemphredon rugifera may be associated with Scots Pine (Pinus sylvestris) but this is probably mere coincidence. Pemphredon species are among those falling prey to the Ichneumon wasp Perithous scurra. The minuscule Nitela lucens (4mm) is also a rarity. They have their antennae set very low on the face and have a very sporadic coverage in southern England.
Certain wasps which hunt spiders but are not from the Pompilidae family are found in woodland and marginal areas, notably the Trypoxylon genus. Trypoxylon medium is focused on in the Heathland pages and Trypoxylon clavicerum in the garden section, which leaves just one species that is distinguished from its peers by having a very long first section ('tergite') to the abdomen.
Trypoxylon attenuatum (8mm) is the species. The whole Trypoxylon tribe is noted for engaging in nest usurpation, an action which makes sense given the time and effort involved in nest construction and foraging by solitary female aculeates of all species. In July 2007 I witnessed an attempted usurpation by a female Trypoxylon attenuatum. The original wasp had been stocking her nest in a cut, dead stem on a bramble for at least a day. The usurper entered the stem without prey and was inside for ten minutes before the ‘owner’ of the nest arrived carrying a spider. Soon after the latter went in, there was a commotion and the females emerged locked in combat, shown in the accompanying image. They fell to the ground and continued struggling but within 30 seconds one flew off. There was no way of knowing whether she was the original occupier or the interloper.
This is known as intraspecific or conspecific parasitism. Such behaviour between different species is also pretty common; an example is shown in the gardens section here with Ectemnius continuus usurping a Pemphredon lugubris.
Gymnomerus laevipes (12mm), which builds up to 12 cells separated by clay partitions in plant stems including bramble and thistles, is one of the Potter/Mason wasps (Eumenids) and has suffered a decline. They are seen from May to July and prey on weevil larvae.
Another Eumenid, Ancistrocerus gazella is on the wing from June to August catching Lepidoptera larva to stock its nest in a cavity in a plant, normally a stem. Brambles are particularly popular but the wasps can utilise elder, holes in masonry or straw in a thatched roof, so they are not too hard to please.
From the same family are three Symmorphus species. Symmorphus gracilis (11mm) and Symmorphus bifasciatus (11mm) are slender and fairly common and seen from May to August. Though seemingly suited by damp places, often near ditches and streams, these wasps nest in a variety of locations, including cavities in walls, plant stems and disused plant galls in which they place beetle larvae for their offspring to feed on. The pictured females on heathland were forced to use sand bound with saliva for the partitions in their nests, not the most amenable substance.
Much rarer, a Red Data Book species, is Symmorphus crassicornis (12mm) but this wasp is in fact rather commoner than was believed a few decades ago. This is because its association with its only prey, the larvae of the handsome Poplar Leaf Beetle Chrysomela populi based on Aspen trees, was not fully appreciated until 1980 or so. Wherever the beetle has been found in Surrey, and to a lesser extent in other counties in the south, the wasp has been found too. This is essentially heathland but the involvement of trees justifies the inclusion of the species here.
Symmorphus crassicornis is seen in July and August flying fast in the vicinity of Aspens. The prey larvae can become pretty large and the wasp doesn't always have an easy time transporting or even taking them – in 2010 I saw a female knocking individual larvae on to the ground to facilitate capture. The beautiful Chrysid wasp Chrysis fulgida (8mm) uses Symmorphus crassicornis as host but is very difficult to come across and is designated RDB 1.
The smallest Eumenid is a fairly recent arrival in Britain. Called Microdynerus exilis, it is only 8mm and was first spotted in 1937. Unlike the rest of the family, the markings are more ivory than yellow. The range has expanded and although still officially scarce, the species is always worth looking for in the south in dead standing wood, an exceptional habitat.
The eight species of ruby-tailed wasps covered by the title Chrysis ignita (average 9mm) cleptoparasitise a wide variety of species dominated by Ancistrocerus. These are the largest of the genus, with the pictured female measuring 11mm.
Pseudomalus auratus (6mm), a chunky species which parasitises Pemphredon and Passaloecus wasps among others, is fairly common but Chrysis gracillima (6mm) is much rarer. A Red Data Book species, this one is relatively elongated compared with most other Chrysid wasps, enabling access to small holes in wood where prey, possibly including Trypoxylon clavicerum (mentioned above) nests.
Three wasps that parasitise bees, Chrysura radians, Monosapyga clavicornis and Sapyga quinquepunctata, are shown on the Bee Parasites page in this section.
Images © Jeremy Early. All rights reserved.