Tag: Entomology

Hoverflies, of the insect family Syrphidae, are often to be found hovering around flowers and, for this reason, are known as flower flies in many parts of the world. The adults of most species feed largely on nectar and pollen making them important pollinators. Their larvae eat a range of foods; some feed on decaying plant and animal matter whilst others are important predators of aphids, thrips and other insects commonly considered to be ‘crop pests’. Although completely harmless to humans and other mammals, many hoverfly species mimic stinging wasps or bees in an effort to protect themselves from predation.

This is the second instalment in our two part guide to UK hoverflies, in which we cover many of the common species that you are likely to encounter in your garden or local outdoor space. Part one can be found here.

Eristalis pertinax

Distribution: Widespread throughout Britain and Ireland.
Habitat: E. pertinax can be found in a number of habitats, including woodlands, gardens and moorland. 
What to look for: Similar in size and appearance to E. tenax (see The NHBS guide to UK hoverflies: Part 1), the easiest character to use to identify this species is the yellow tarsi (the last segments of the leg) on the front and middle legs. The abdomen tapers towards the end, giving it a triangular shape that can also help to separate this species from E. tenax. 
Months active: March to November, with peaks in both May and August.
Did you know: This is one of the first species to emerge in the spring, when males can often be seen defending territories in woodland rides and around flowers. 

The Eristalis genus includes a number of common species that are likely to be encountered in gardens, such as E. pertinax and E. arbustorum. The May issue of British Wildlife magazine includes an article by Roger Morris and Stuart Ball that provides an introduction to the Eristalis genus, and includes an identification key to the ten Eristalis species that occur in the UK. 

Baccha elongata

Distribution: Widespread throughout Britain and Ireland, although less common in parts of Scotland.
Habitat: Prefers shaded spots, such as woodland margins and hedgerows.
What to look for: Although generally overlooked due to its small size, B. elongata is unmistakable because of its long, slender, wasp-like abdomen.
Months active: April to November, with peaks in both May and September.
Did you know: Unlike many other hoverflies, B. elongata is rarely seen basking in sunlit areas but tends to be found in low, shaded vegetation. The predatory larvae feed on a number of aphid species, such as Nettle Aphid and Bramble Aphid.

Episyrphus balteatus

Distribution: Widespread throughout Britain and Ireland.
Habitat: A wide range of habitats, including gardens and woodlands.
What to look for: Episyrphus balteatus, often known as the Marmalade Hoverfly, is an easily recognisable species and one of the most common hoverflies in the UK  – it won’t take too long for you to spot this regular garden visitor. Each of the abdominal segments has two black bands separated by orange bands. This pattern is unique to this species, but the overall colouration of individuals can vary depending on the temperature at which the larvae develop. 
Months active: Individuals can be recorded in all months of the year, but there is usually a peak in numbers in July.  
Did you know: The arrival of huge numbers of migrants from mainland Europe can sometimes lead to reports in the media of a mass influx of ‘wasps’. 

Scaeva pyrastri

Distribution: Widespread in England, Wales and Ireland, but much less common in Scotland.
Habitat: Can be found in a variety of habitats, including gardens and woodlands.
What to look for: White, comma-shaped spots on the abdomen are a key identification feature, but completely black individuals can occur. 
Months active: May to November, with a peak in August.
Did you know: S. pyrastri is a migratory species and its numbers in Britain vary greatly between years.  

Leucozona lucorum

Distribution: Widespread throughout Britain and Ireland, although less abundant in northern Scotland.
Habitat: Woodland rides and edges, and hedgerows.
What to look for: The black wing clouds and broad creamy markings on the second abdominal segment are distinctive characteristics of this species. Confusion can occur with the similar Cheliosa illustrata, but the yellow scutellum (a shield-shaped segment behind the thorax) of L. lucorum will help with identification. 
Months active: Between May and August, with a peak in May and June.
Did you know: L. lucorum is primarily a spring species, but in some years there is a second generation in midsummer. 

Helophilus pendulus

Distribution: Widespread throughout Britain and Ireland.
Habitat: A wide range of habitats, including gardens.
What to look for: A very eye-catching hoverfly with pale, longitudinal stripes on its thorax and a yellow face with a dark central stripe. It is possible to confuse this species with H. hybridus, although the yellow markings on the second and third abdominal segments are separated by a black band. 
Months active: Between April and November with a peak in July.
Did you know: H. pendulus is commonly seen basking on leaves and often produces a buzzing sound while doing so. 

Syritta pipiens

Distribution: Widespread in Britain and Ireland, although less abundant in parts of northern Scotland.
Habitat: A variety of habitats and common in gardens.
What to look for: Despite being a small, slender species, S. pipiens is instantly recognisable by the swollen hind femora. The sides of the thorax are also dusted grey.  
Months active: April to November, but more abundant in late summer. 
Did you know: Male S. pipiens are highly territorial and will force each other to move backwards and forwards until one admits defeat and gives up. 

Volucella zonaria

Distribution: Widespread in southern England and parts of Wales.
Habitat: A variety of habitats, including gardens and parks in urban areas
What to look for: Britain’s largest hoverfly, this species is often known as the Hornet Hoverfly due to the strong yellow-and-black bands on the abdomen and the impressive size (wing length can be between 15.5mm and 19.5mm). The only other hoverfly that V. zonaria could be confused with is V. inanis, but the latter is largely yellow underneath whereas V. zonaria is chestnut coloured with broad black bands. 
Months active: May to November, with a peak in August. 
Did you know: V. zonaria is a relatively recent addition to the British fauna. It first colonised the south of England in the 1930s and its range is rapidly expanding. The larvae live in the nests of social wasps, such as the Hornet and Common Wasp. 

Sphaerophoria scripta

Distribution: Widespread in England and Wales, but only recorded from the east coast of Ireland and less abundant in northern England and Scotland. 
Habitat: Grasslands.
What to look for: Identifying individual species in the Sphaerophoria genus, particularly females, can be extremely difficult. Male S. scripta can be easier to identify as the abdomen is much longer than the wings and has broad yellow bands, although the markings can vary. Confusion can occur with S. batava and S. taeniata, as these two species also have yellow bands; examination of the male genitalia is the only way to determine identification. 
Months active: Between April and November, with a peak in July and August
Did you know: This is the most common Sphaerophoria species and is often found in grassland. There is no resident population in northern Britain, but numbers are boosted in some years by an influx of migrant individuals. 

Chrysotoxum bicinctum

Distribution: Widespread in Ireland and southern England, but less common in northern England and Scotland. 
Habitat: Open grasslands and grassy woodland rides.
What to look for: The yellow bars on the second and fourth abdominal segment and the chocolate-brown patches on the wings make this wasp mimic instantly recognisable. 
Months active: May to September, with a peak between June and August. 
Did you know: Members of the Chrysotoxum genus are easy to recognise due to their long antennae which point forwards. Other hoverfly groups with similar antennae do not have the yellow-and-black markings of Chrysotoxum.  

Cheilosia illustrata

Distribution: Widespread throughout Britain and Ireland, although less abundant in the north-east of Scotland.
Habitat: Hedgerows and woodland edges where umbellifers such as Hogweed or Angelica are present.
What to look for: Not an entirely believable bumblebee mimic, C. illustrata has a band of pale hairs at the end of the abdomen and dark wing clouds. It is possible to mistake this species for Leucozona lucorum, but the black face and black scutellum of C. illustrata help to distinguish it.
Months active: April to September, peaking in July.
Did you know: The larvae of this species mine the roots and stems of large Hogweed plants and the adults are often observed feeding on the flowers. 

Recommended books and equipment

Britain’s Hoverflies: A Field Guide
£17.99 £24.99

A beautifully illustrated photographic field guide to the hoverflies of Britain, focusing on the species that can be most readily identified.

 

 

British Hoverflies: An Illustrated Identification Guide
£37.50

In this classic work by Stubbs and Falk, 276 species are described. Their identification is made easy by the extensive keys which incorporate over 640 line drawings.

 

60ml Collecting Pot
From £0.35

These small sampling containers are made from see-through polypropylene and have secure screw-on lids. They are ideal for the temporary storage of specimens.

 

 

Opticron Hand Lens (10x 23mm)
£12.95 £14.95

Observe the finer details of your specimen with this high-quality 23mm doublet lens, the most commonly recommended magnifier for all types of fieldwork.

 

Sweep Net
£31.99

This high-quality sweep net is designed for catching insects and other bugs from long grass and shrubs

 

All prices are correct at the time of posting, but may change at any time.
Please see nhbs.com for up to date pricing and availability.

With approximately 7,000 species, the Diptera (true flies) are one of the biggest insect orders in Britain and Ireland, second only to Hymenoptera (the bees, wasps and ants). Of these species, over 280 belong to the family Syrphidae, the hoverflies. Known as ‘flower flies’ in other parts of the world, hoverflies are frequent visitors to flowering plants and are a familiar sight in our gardens and woodlands, and a wide range of other habitats. You would be forgiven for mistaking a hoverfly for a bee or wasp, as some species are amazing mimics in terms of both their appearance and behaviour, although some are more convincing than others.

Hoverflies are important, and often overlooked, pollinators, and their larval stages are incredibly diverse. Some larvae are predatory, feeding on aphids or eating grubs within the nests of ants, social bees or wasps, while others feed on the roots, stems or leaves of plants, or on dead and decaying organic matter, such as rotting wood or material collected in rot holes in trees.

Although many hoverflies are brightly coloured or distinctively patterned, there are plenty of inconspicuous species that resemble flies in other families. The first step is therefore to determine that a fly is in fact a hoverfly. In general hoverflies lack the strong bristles we see in other flies, such as the house fly, but the key characteristic is their wing venation. Unlike other flies, hoverflies have a ‘false vein’ on their wing, and although this is a difficult feature to get an eye for initially, it can be obvious in good photos and becomes easier to spot with practice. Another clue is in the name; hoverflies are remarkable fliers and many species are able to hold their position in flight for an incredible length of time.

Hoverfly identification can be difficult, and in some cases it is necessary to inspect a specimen under a microscope for a positive ID. There are many garden visitors that are more straightforward, however, and with a good field guide, a hand lens and a camera to take clear photos with, you can easily get started in learning more about this attractive group of insects. There are fantastic resources online too, such as the UK Hoverflies group on Facebook, which provides help with identification and allows members to share their observations.

This is the first of two hoverfly identification guides, and in both of these blogs we will be covering the more common species that you are likely to encounter in your garden or local patch.

Eristalis tenax

Distribution: Widespread throughout Britain and Ireland. E. tenax is thought to be the most widespread hoverfly species in the world.
Habitat: A wide range of habitats including gardens, woodlands and meadows.
What to look for: A convincing honey-bee mimic that can be easily told from other species of Eristalis by three obvious characteristics: a thickened, curved hind tibia; a broad, dark facial stripe; and vertical stripes of dark hairs on the eyes.
Months active: Present throughout the year, but most frequently recorded between February and April, and June and November.
Did you know: Females hibernate over the winter, and males are increasingly being recorded hibernating during warmer winters in southern England. The aquatic larvae, or ‘rat-tailed maggots’, live in wet, decaying vegetation

The Eristalis genus includes a number of common species that are likely to be encountered in gardens, such as E. pertinax and E. arbustorum. The May issue of British Wildlife magazine includes an article by Roger Morris and Stuart Ball that provides an introduction to the Eristalis genus, and includes an identification key to the ten Eristalis species that occur in the UK.

Myathropa florea

Distribution: Widespread throughout Britain and Ireland.
Habitat: A variety of habitats, but found in woodlands especially.
What to look for: Similar to some Eristalis species, Myathropea florea is a distinctive black-and-yellow species with a bat-like pattern on its thorax, although this can vary and cause confusion in less clearly marked individuals.
Months active: April to October.
Did you know: Like other species in the Eristalini tribe, M. florea larvae are known as ‘rat-tailed maggots’ and are found in wet hollows containing decaying vegetation, although they have been reported making use of any containers holding water and dead vegetation, such as buckets or water butts.

Syrphus ribesii

Distribution: Widespread throughout Britain and Ireland.
Habitat: A number of habitats including woodlands, gardens and hedgerows.
What to look for: Females can be easily identified by their completely yellow hind femora, although males are harder to distinguish from two other common Syrphus species, S. torvus and S. vitripennis. Male S. ribesii can be separated from S. torvus by their bare eyes, but a microscope is needed to reliably separate males of S. ribesii and S. vitripennis. 
Months active: From March to November, with peaks in May–June and July–September. 
Did you know: Male S. ribesii will emit a noticeable humming noise from tree canopies, caused by vibrating their wings at a high frequency when resting. 

Merodon equestris

Distribution: Widespread in Britain and Ireland, but less abundant in parts of Scotland.
Habitat: Often recorded in gardens and urban areas.
What to look for: A hairy bumblebee mimic that has swollen hind femora with triangular projections – a characteristic unique among bumblebee mimics. M. equestris can occur in a range of colour forms to mimic different bumblebee species. 
Months active: Between April and September, with a peak in late May and early June.
Did you know: The larvae develop in the bulbs of many different bulb-forming plants, but they are especially associated with daffodils and can be a pest in some cases. They are thought to have been introduced to Britain in the 19th century in daffodil bulbs. 

Platycheirus albimanus

Distribution: Widespread throughout Britain and Ireland.
Habitat: Woodland edges and hedgerows, and often seen in gardens.
What to look for: Females are easier to recognise due to their yellow legs and silver spots on their black abdomen. Males tend to have bronze-coloured spots, a front tibia that is significantly broader at the end, and front femora that have distinctive clumps of long hairs. It is possible to confuse males with similar species such as P. aurolateralis, P. scutatus, and P. splendidus, and so close examination of the legs is required. 
Months active: Between March and November, with peaks between May and June, and July and August.
Did you know: A common garden visitor, particularly in spring, P. albimanus is often found in low vegetation such as nettles or brambles.

Eupeodes corollae

Distribution: Widespread in Britain, although less abundant in northern Scotland.
Habitat: Recorded in almost any habitat, from gardens to mountain tops.
What to look for: Males and females are quite different in appearance, but both have broad yellow markings that reach the edges of the abdomen. The males also have an obvious genital capsule. 
Months active: March to November, with a peak between July and August.
Did you know: E. corollae is found in a wide variety of habitats. An influx of migrants or a mass emergence of individuals results in a peak in numbers in midsummer.

Melanostoma mellinum

Distribution: Widespread throughout Britain and Ireland.
Habitat: Grasslands. 
What to look for: It is easy to confuse this species with M. scalare, and so close examination is required. In females, the top of the head is a shining black with very narrow dust spots by the eyes, while the abdomen has distinctive yellow markings. Males have a relatively short abdomen and the second and third segments are as wide as they are long. 
Months active: April to October, with peaks in May–June and July–August. 
Did you know: This is one of the most common hoverfly species in the UK and is often recorded from grasslands, although it can also be found in high numbers in the uplands such as on moorland or mountainsides. 

Chrysogaster solstitialis

Distribution: Widespread in Britain and Ireland, but rare in parts of northern Scotland.
Habitat: Woodlands, road verges and hedgerows.
What to look for: A small, dark hoverfly (even the wings are dark) with bright red eyes. Confusion can occur with other Chrysogaster species, or even small house flies.
Months active: May to October, with a peak in July and August.
Did you know: A common woodland species, particularly in damp and shady locations. C. solstitialis is often seen in concentrated numbers on umbellifers such as Hogweed and Angelica. 

Rhingia campestris

Distribution: Widespread throughout Britain and Ireland.
Habitat: Woodlands and field edges, but found in a variety of habitats.
What to look for: The long snout and orange abdomen make this an unmistakable species. The only potential for confusion is with the UK’s other Rhingia species, R. rostrata, but the dark edges of the abdomen and overall darker colouration of R. campestris are distinctive.
Months active: April to October, with peaks between May and June, and August to September. 
Did you know: The long snout allows R. campestris to feed on plants with deep tubes, such as bluebells, which other hoverflies cannot use. The larvae breed in cow dung, although other breeding habitats are also thought to be used as adults can occur in high numbers where there are few or no cattle. 

Sericomyia silentis

Distribution: Widespread in Britain and Ireland, although absent from central England and scarce in south-east England.
Habitat: Acidic, boggy habitats, such as wetlands and heathlands.
What to look for: A large wasp mimic with distinctive black-and-yellow banding – it is very unlikely that this species would be confused with any other hoverfly. 
Months active: May to November, with a peak in July.
Did you know: This is a very mobile species, which is often found far from breeding sites. It visits a range of plants, but seems to have a preference for red or purple flowers, such as Devil’s-bit Scabious. 

Ferdinandea cuprea

Distribution: Widespread in Ireland, Wales and southern England, but rarely occurs in high numbers.
Habitat: Woodland.
What to look for: Easily recognisable, F. cuprea has a metallic, brassy abdomen with grey longitudinal stripes on the thorax. The thorax also has strong bristles on its side, which is quite uncommon for a hoverfly.
Months active: March to November, with a peak in June.
Did you know: F. cuprea is rarely seen visiting flowers, and is more likely to be seen basking on tree trunks, wooden posts or even telegraph poles.

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Suggested reading and equipment:

Britain’s Hoverflies: A Field Guide

£24.99

 

 

 

 

British Hoverflies: An Illustrated Identification Guide

£37.50 

 

 

 

60ml Collecting Pots

£0.35

 

 

 

 

Opticron Hand Lens 23mm 10x Magnification

£12.95 £14.95

 

Sweep Net

£31.99

 

 

 

All prices correct at the time of this article’s publication.

Shieldbugs are insects in the superfamily Pentatomoidea. They are characterised by their well-developed scutellum, the hardened extension of the thorax over the abdomen. Many shieldbug species are triangular, with a broad pronotum and pointed end to the abdomen. They also produce a foul-smelling liquid from their prothoracic glands, which inspired the American name “stink bug”, although this name is specific to the family Pentatomidae.

Some shieldbugs are considered pest species due to the damage they can cause to crops. The recent arrival of the brown marmorated stink bug (Halyomorpha halys) to the UK is considered a serious threat to fruit and vegetable crops. They damage the salability of produce and can even contaminate the taste of juice or wine, causing waste and a loss in income.

Identifying shieldbugs is usually based on structural characteristics, body length (from the head to the end of the abdomen, ignoring the antennae and legs), and species range. Colouration and pattern can be useful but there is often variation between individuals of the same species. Using a hand lens, sweep net or beating tray can help when surveying for shieldbugs. A field guide that includes juvenile stages would also be useful as nymphs can often have different colour patterns to adults.

Hawthorn Shieldbug (Acanthosoma haemorrhoidale)

Distribution: Widespread across the UK.
What to look for: The most common shield bug in the UK, the hawthorn shieldbug is also UK’s largest. Its scutellum and pronotum are green, framed with red sides. The ‘shoulders’ of its pronotum are pointed with red and black tips, and its corium, the thickened basal portion of the forewing, is red. Its wing membrane can vary in colour but is usually red.
Similar species: The birch shieldbug (Elasmostethus interstinctus) but this species does not have a green scutellum. The juniper shieldbug (Cyphostethus tristriatus) is also similar but this species does not have a red wing membrane.

Common Green Shieldbug (Palomena prasina)

Distribution: Widespread in England, Wales, and parts of Northern Ireland.
What to look for: This is a larger species, with a dark wing membrane and a bright green body during summer. The adults become a bronze-brown colour in the autumn before hibernating throughout winter.
Similar species: The southern green shieldbug (Nezara viridula), a non-native species. However, this species has paler wings than the common green shieldbug.

Parent Bug (Elasmucha grisea)

Distribution: Occurs across the UK but most commonly in south-east and central England.
What to look for: This is a medium-sized species with red and beige colouration. Most individuals have a black patch on the scutellum. This species also has a black and white connexivum, the flattened lateral border of the abdomen.

Pied Shieldbug (Tritomegas bicolor)

Distribution: Widespread across the south-east and central England.
What to look for: This species does not have the characteristic triangular shape and could be confused for a ladybird. It has a black and white piebald pattern, with a grey or translucent wing membrane. Its pronotum is black with a white spot on each ‘shoulder’.
Similar species: Rambur’s pied shieldbug (Tritomegas sexmaculatus), although this species has a black wing membrane.

Juniper Shieldbug (Cyphostethus tristriatus)

Distribution: Common in southern and central England, with an expanding range.
What to look for: This is a bright green species, with a green pronotum, head and scutellum. They have pinkish-red markings on their corium. Their wing membrane is green with a black X-shaped mark.
Similar species: The birch and hawthorn shield bugs are visually similar but neither species has the black X-shaped mark on their wing membrane.

Striped Shieldbug (Graphosoma italicum)

Distribution: First recorded in the UK in 2020, only found in two sites in London.
What to look for: Also known as the Italian striped bug and the minstrel bug, their body is rounded with bold red and black longitudinal stripes. Their connexium is black with several black, square-shaped spots.
Similar species: There are several similar species, such as Graphosoma lineatum, but none are found in the UK.

Ornate Shieldbug (Eurydema ornata)

Distribution: Coastal areas between Devon and Sussex, scattered in other parts of southern England.
What to look for: They have a distinctive red and black pattern across their pronotum and abdomen. There are other colour morphs, however, and they can have a white and yellow background with the same black markings. They have a black head with a red, white or yellow ‘mouth’ shape and a black wing membrane.
Similar species: The scarlet shieldbug (Eurydema dominulus). They can be distinguished by the pattern on their corium. The ornate shieldbug has a thin black line, two spots and a washed-out area, compared to the thicker line, one or no spots and no washed-out area on the scarlet shieldbug.

Blue Shieldbug (Zicrona caerulea)

Distribution: Widespread across Britain, particularly in the north, and absent from Ireland.
What to look for: The blue shieldbug has a deep blue-green metallic sheen, with a dark wing membrane. They resemble leaf beetles, species in the Altica genus, whose larvae they predate upon. This is called aggressive mimicry, where a predator resembles its prey to avoid detection.

Bishop’s Mitre Shieldbug (Aelia acuminata)

Distribution: Widespread across southern Britain.
What to look for: This is a straw-coloured species, with brown longitudinal stripes, a distinctive pointed head and a ridged pronotum.
Similar species: Mecidea lindbergi is another elongated shield bug but it is a thinner species without brown stripes.

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Suggested reading and equipment:

Guide to Shieldbugs of the British Isles

£3.75

 

 

 

 

A Pocket Guide to the Shieldbugs and Leatherbugs of Britain and Ireland

£12.99 

 

 

 

 

Standard Sweep Net

£29.95 

 

 

 

 

Beating Tray

£49.96

 

 

 

 

 

Invicta Pooter

£3.95

 

 

 

 

 

60ml Collecting Pot

From £0.35

 

 

 

 

Opticron Hand Lens 23mm 15x Magnification

£14.50 £16.50

 

All prices correct at the time of this article’s publication.