Wednesday 5 January 2022

Wildlife Review 2021- Wasps and Sawflies


No less than 51 species across several families were recorded during the year including seven new for the Recording Area. This was a good return for a very large and diverse suborder of insects that often require specimens to enable identification.

Social wasps were the first on the wing with Common Wasp Vespula vulgaris and German Wasp V.germanica appearing by early April, several nests of both species were found and the wasps were active well into November. A Median Wasp Dolichovespula media was found on 28 August. A couple of Hornet V.crabro were found in September and October, a good return for a species that is less than annual.

Hornet - Alan Keatley

The first new species of the year was a chalcid wasp on 14 May, this rarely observed tiny wasp was identified as Encyrtus infidus, a parasite of scale insects. Coincidentally the last new species of the year on 12 December was also a chalcid parasite of scale insects, Microterys seyon.

Encyrtus infidus - Alan Keatley

The main season for solitary wasps starts mid May and goes onto October for some species. The reserve is the home to many mason and digger wasp species. No less than 16 digger wasp and four mason wasp species were recorded. One new digger wasp was found, a Red-bodied Stem Wasp Rhopalum clavipes on 6 August, with Minute Black Wasp Diodontus minutus on 9 July having gone unnoticed for many years. 

Red-bodied Stem Wasp - Alan Keatley

The four mason wasps recorded were Early Mason Wasp Ancistrocerus nigricornis, Little Mason Wasp Microdynerus exili, Small-notched Mason Wasp A.gazella and Willow Mason Wasp Symmorphus bifasciatus.

A good place to look for these wasps is on flowering umbellifers from June onwards, with Beewolf Philanthus triangulum, Common Ectemnius E.continuus, Common Spiny Digger Wasp Oxybelus uniglumis, Field Digger Wasp Mellinus arvensis, Large Ectemnius E.cephalotes, Ornate-tailed Digger Wasp Cerceris rybyenis and Slender-bodied Digger Wasp Crabro cribrarius all nectaring on these as well as other flowers such as Water Mint and Gypsywort.

Beewolf - Kevin Rylands

Others are more readily found on leaves and bare ground and the following species were found; Crossocerus megacephalus, C.quadrimaculatus & C.wesmaeli, Dryudella pinguis, Four-banded Digger Wasp Gorytes quadrifasciatus and Shieldbug Digger Wasp Astata boops. Three-spotted Digger Wasp Nysson trimaculatus was seen searching out Four-banded Digger Wasp nests to lay its eggs. 

Spider hunting wasps could be seen from from 31 May with the Red-legged Spider Wasp Episyron rufipes nectaring on Hogweed. Spider wasps spend their time on bare ground seeking out spider prey with Leaden Spider Wasp Pompilus cinereus the most obvious. A new species for site, Variable Spider Wasp Dipogon variegatus found on 14 August.

Leaden Spider Wasp (male & female) - Alan Keatley

Red-banded Sand Wasp Ammophila sabulosa, the only invertebrate on the SSSI citation, were looking for caterpillars along the Dune Ridge from 27 May, with Dull Cuckoo Wasp Hedychridium roseum seeking its host - Shieldbug Digger Wasp from 31 July. The Javelin Wasp Gasteruption jaculator was also active from the same date. Another new species found was the strange wingless wasp, Gelis agilis.

Hedychridium roseum - Alan Keatley

Galls wasps are rarely observed, or at least identified, as adults but the galls they on host plants help indicate their presence. Several galls were found including two new species on Oak, Smooth Spangled Gall Wasp Neuroterus albipes and Artichoke Gall Wasp Andricus foecundatrix. Other species recorded included Bedeguar Gall Wasp Diplolepis rosae (Robin's Pincushion) on Rose, Ram’s-horn Gall Wasp A.aries, Silk-Button Spangle Gall Wasp N.numismalis, Oak Marbled Gall Wasp A.kollariPasty Gall Wasp N.saliens, Oyster Gall Wasp N.anthracinus and Knopper Gall Wasp A.quercuscalicis, all on Oak, Bramble Stem Gall Wasp Diastrophus rubi and Cat’s-ear Stem Gall Wasp Phanacis hypochoeridis.

Andricus foecundatrix Artichoke Gall - Kevin Rylands

Ichneumon wasps are frequently found on site, but mainly go unnamed due to the complexity of identification. Several can be identified and the following were seen this year; Enicospilus ramidulus on 10 June, Amblyteles armatorius on 12 June, Pimpla rufipes on 3 September, Apechthis compunctor on 30 October, Stenichneumon culpator (a new species) on 4 November and Ophion obscuratus caught in a light-trap on 9 November.

Amblyteles armatorius - Alan Keatley


Sawflies are in the same order as bees, ants and wasps (Hymenoptera), in many species identification is difficult, however association with a particular foodplant and their larval leaf mines can help.

A total of 20 species were recorded this year including nine new species. The Warren sawfly list now stands at 41.

The first of the year was also a new species; Monophadnus pallescens, a black sawfly associated with buttercups, it was recorded on 8 April. Another new species was found on 17 April, was Euura bergmanni, a willow sawfly. 

Euura bergmanni - Alan Keatley

The similar looking Aglaostigma aucupariae and A.fulvipes, both associated with bedstraws were found on 29 April and 7 May respectively. They are common on site and can be often found together. Bramble Sawfly Arge cyanocrocea and Marcophya duodecimpunctata - a grass and sedge feeding species, were seen on 19 May. 

Aglaostigma fulvipes - Alan Keatley

Another common species the Dog Rose Sawfly Macrophya annulata, a black and red sawfly that mimics a spider hunting wasp in appearance and behaviour, was added on 19 June.

The Rose Leaf-rolling Sawfly Blennocampa phyllocolpa and Scolioneura viana, a Birch sawfly were recorded on 20 June, the latter also a new species for the Warren. 

In July Heterarthrus vagans, an Alder sawfly - on 11th and H.aceris, a Sycamore sawfly on 15th were also identified by larval leaf mines, the latter a new species.  The Oak Slug Sawfly Caliroa annulipes, the second new species of the month was added on 18th. The Turnip Sawfly Anthalia rosae emerged in large numbers from 29th.

Monophadnus pallescens - Alan Keatley

Other sawflies identified by leaf mine included; Scolioneura betuleti on Birch on 12 August, Hemichroa australis on Birch and Alder on 12 September, Fenusa pumila on Birch on 26 September, Fenuelia nana on Birch on 29 September and two new species in November, Profenusa pygmaea on Oak on 3rd and Heterarthrus ochropoda on Poplar on 5th.

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