''Symmorphus bifasciatus'', the willow mason-wasp, is a species of

potter wasp Potter wasps (or mason wasps), the Eumeninae, are a cosmopolitan wasp group presently treated as a subfamily of Vespidae, but sometimes recognized in the past as a separate family, Eumenidae. Recognition Most eumenine species are black or brown, ...

, from the subfamily

Eumeninae Potter wasps (or mason wasps), the Eumeninae, are a cosmopolitan wasp group presently treated as a subfamily of Vespidae, but sometimes recognized in the past as a separate family, Eumenidae. Recognition Most eumenine species are black or brown, ...

of the social wasp family

Vespidae The Vespidae are a large (nearly 5000 species), diverse, cosmopolitan family of wasps, including nearly all the known eusocial wasps (such as ''Polistes fuscatus'', ''Vespa orientalis'', and ''Vespula germanica'') and many solitary wasps. Each ...

which is widely distributed in the

Palearctic The Palearctic or Palaearctic is the largest of the eight biogeographic realms of the Earth. It stretches across all of Eurasia north of the foothills of the Himalayas, and North Africa. The realm consists of several bioregions: the Euro-Sibe ...

region.

Description

''Symmorphus bifasciatus''is one of the two small '' Symmorphus'' species found in Britain which have a transverse ridge along the front edge of the

pronotum The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites (exoskeletal plates) are the pronotum (dorsal), the prosternum (ventral), and the propleuron (lateral) on ea ...

. It is distinguished from the other '' Symmorphus connexus'' by having denser punctures on the

mesonotum The mesothorax is the middle of the three segments of the thorax of hexapods, and bears the second pair of legs. Its principal sclerites (exoskeletal plates) are the mesonotum (dorsal), the mesosternum (ventral), and the mesopleuron (lateral) on ...

mesopleuron The mesothorax is the middle of the three segments of the thorax of hexapods, and bears the second pair of legs. Its principal sclerites (exoskeletal plates) are the mesonotum (dorsal), the mesosternum (ventral), and the mesopleuron (lateral) on ...

and

frons Insect morphology is the study and description of the physical form of insects. The terminology used to describe insects is similar to that used for other arthropods due to their shared evolutionary history. Three physical features separate insec ...

, and because it normally shows yellow patches on the

and scutellum.

Distribution

''Symmorphus bifasciatus'' is found from Great Britain, as far north as

Highland Highlands or uplands are areas of high elevation such as a mountainous region, elevated mountainous plateau or high hills. Generally speaking, upland (or uplands) refers to ranges of hills, typically from up to while highland (or highlands) is ...

in northern Scotland, east to north eastern

Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of ...

Korea Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic o ...

and

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

, south to

Central Asia Central Asia, also known as Middle Asia, is a subregion, region of Asia that stretches from the Caspian Sea in the west to western China and Mongolia in the east, and from Afghanistan and Iran in the south to Russia in the north. It includes t ...

Biology

''Symmorphus bifasciatus'' is a tube-nesting wasp, utilising existing cavities including the hollow stems of plants and the disused plant galls of ''

Cynips kollari ''Cynips'' is a genus of gall wasps in the tribe Cynipini, the oak gall wasps. One of the best known is the common oak gall wasp (''Cynips quercusfolii''), which induces characteristic spherical galls about two centimeters wide on the undersides ...

'', where the female wasp constructs a number of cells, separated from each other by walls made of clay. ''S. bifasciatus'' hunts for the larvae of the

leaf beetle The insects of the beetle family Chrysomelidae are commonly known as leaf beetles, and include over 37,000 (and probably at least 50,000) species in more than 2,500 genera, making up one of the largest and most commonly encountered of all beetle ...

Phyllodecta vulgatissima The blue willow beetle (''Phratora vulgatissima''), formerly ''Phyllodecta vulgatissima'', is a herbivourous beetle of the family Chrysomelidae. It is dark with a metallic sheen that ranges from a blue color to bronze. It is distinguished from ...

'', which are immobilised by stinging and carried back to the nest by the mandibles and forelegs to supply the cells. Once there is sufficient food in the cell, usually between 10 and 17 grubs which are tightly packed, the female lays an egg in the cell. The egg hatches in two or three days after laying, while the larvae mature in one or two weeks undergoing a probable five instars. Once the larve has finished feeding it may rest for around one day before it voids its gut contents towards the inner end of the cell and then spins a cocoon which it fixes to the base of the cell. The flight period is from May to October; but activity peaks between June and August, but they are especially active in July. Adults are known to feed on the nectar of

figwort The genus ''Scrophularia'' of the family Scrophulariaceae comprises about 200 species of herbaceous flowering plants commonly known as figworts. Species of ''Scrophularia'' all share square stems, opposite leaves and open two-lipped flowers for ...

Apiaceae Apiaceae or Umbelliferae is a family of mostly aromatic flowering plants named after the type genus ''Apium'' and commonly known as the celery, carrot or parsley family, or simply as umbellifers. It is the 16th-largest family of flowering plants ...

and

spurge ''Euphorbia'' is a very large and diverse genus of flowering plants, commonly called spurge, in the family Euphorbiaceae. "Euphorbia" is sometimes used in ordinary English to collectively refer to all members of Euphorbiaceae (in deference to t ...

. The

cuckoo wasp Commonly known as cuckoo wasps or emerald wasps, the hymenopteran family Chrysididae is a very large cosmopolitan group (over 3000 described species) of parasitoid or kleptoparasitic wasps, often highly sculptured, with brilliant metallic colors ...

s ''

Chrysis angustula ''Chrysis angustula'' is a species of cuckoo wasps, insects in the family Chrysididae. Subspecies Subspecies include: * ''Chrysis angustula alpina'' Niehuis, 2000 * ''Chrysis angustula angustula'' Schenck, 1856 Distribution This rather common T ...

'' and ''

Chrysis ignita ''Chrysis ignita'' is a species of cuckoo wasp. It is one of a group of species which are difficult to separate and which may be referred to as ruby-tailed wasps. Cuckoo wasps are kleptoparasites – they lay their eggs in the nests of other spec ...

'' have been recorded as

brood parasite Brood parasites are animals that rely on others to raise their young. The strategy appears among birds, insects and fish. The brood parasite manipulates a host, either of the same or of another species, to raise its young as if it were its own ...

s of ''Symmorphus bifasciatus'' in Europe.

References

{{Taxonbar, from=Q2374616 Hymenoptera of Europe Vespidae Potter wasps Insects described in 1761 Taxa named by Carl Linnaeus