TECHNICAL | PPC104 AUGUST 2021

Paul Westgate, of BPCA member company Veritas Pest Consultancy, explains how a little entomology know-how can go a long way.

SPEED VIEW: 

• Pest species represent less than 0.5% of British insects
• Knowing common non-pest insects saves time and money and ensures customers have a positive experience
• The majority of hoverfly species superficially resemble social wasps and bees
• By knowing ground beetle and rove beetle characteristics we can identify some 1,500 British insects
• Bush crickets cause concern as their long antennae and curved abdominal cerci can resemble cockroaches
• Of the 1,600+ recorded species of micro-moths, several may be confused with true pest species.

There’s a staggering number of insect species in Britain. Estimates vary, but there are probably around 26,000 species on our little islands.

Of these, there are:

• 7,000+ species of true flies (Diptera)
• 4,500+ species of beetles (Coleoptera)
• 270+ species of bees (Apoidea)
• And even 62 species of fleas (Siphonaptera).

Knowing all these species is beyond the capabilities of even the most dedicated entomologist.

However, being able to identify some of the common and most frequently encountered insects that find their way into people’s lives is a sensible and productive skill to develop for all pest professionals.

Know your imposter pests

As pesties, we’re well versed in the need to identify our ‘pest’ species, be they German cockroaches or case-bearing clothes moths, and we should be consistently building this crucial skill.

However, it is worth remembering that pest species represent only a tiny fraction (less than 0.5%) of the British species count.

The insects in this article are some of those which have been found or presented to me as ‘pests’ during 20 years of conducting fieldwork. They barely scratch the surface of what you might come across.

Knowledge of some of these common insects not only saves you time and money but it ensures our customers have a positive experience from a true professional that they’ll recommend to others.

Hoverflies

Some insects don’t help us and deliberately hide their identity. The majority of hoverfly species (Syrphidae) superficially resemble social wasps and bees.

Upon examination, their generally flatter abdomen and hovering behaviour are usually sufficient to separate these from the true bees and wasps (Hymenoptera), although some can require further examination.

The presence of only two wings, with the rear ‘wings’ adapted to form knob-like halters, will quickly dismiss any other order of insects other than the true flies (Diptera).

Ground beetles

It’s not always necessary to identify insects through to their species.

By knowing the characteristics of the ground beetle (Carabidae) and rove beetle families (Staphylinidae) we can identify (to family-level) some 1,500 British insects professionally resolving any potential treatment needs.

Rove beetles, typified by the bold devil’s coach horse (Ocypus olens), are typically elongated, slender beetles with short elytra, which leave much of the abdomen visible.

Chafers

One of the most requested identifications from customers comes from the dung beetle family (Scarabaeidae). Most often it turns out to be one of the chafers (subfamily Melolonthinae).

In summer the cockchafer (Melolontha melolontha) is the most often encountered. Up to 35mm long, these large beetles are often mistaken for cockroaches and commonly enter houses as they’re attracted by lights.

There are eight species of chafer in Britain and, while they might annoy or frighten a customer, they pose no risk to human health – although some can be horticultural pests, damaging garden plants.

Weevils

There are several weevils (superfamily Curculionidae) that regularly require intervention from a pest professional.

All stored product and wood boring weevils are no more than 4mm long, brown in colour with the typical weevil elbowed antennae and clear rostrum.

Two of the most common and obvious non-pest weevil species are easily distinguished from their stored-product-pest counterparts.

The vine weevil (Otiorhynchus sulcatus) is a common garden visitor, and is black and much larger at 7-9mm while the broad-nosed weevil (Sitona lineatus) lacks the typical weevil rostrum and is striped.

Honey bee

The honey bee is one of 270 British bees. Most bee species are solitary or small nest formers and usually require no actions. Most don’t sting and perform a valuable role as pollinators.

Honey bees can often easily be identified by their size, colour and actions, but a close look at their forewing, noting the three submarginal cells (image above, blue pointers) and extended radial cell (red pointer) will confirm their identity.

Moths

The Lepidoptera order is superficially split into moths and butterflies with the moth group further divided into macro and micros (ie big and small ones).

The macro moths, while fascinating and often beautiful, can easily be identified and offer no pest control issues (although their high numbers may indicate proofing issues that should be resolved as part of our IPM plan).

Of the 1,600+ recorded species of micro-moths, there are several that may be confused with true pest species.

The bee moth (Aphomia sociella), often indicative of a previous wasp or bee nest in which the larvae develop, and the light brown apple moth (Epiphyas postvittana) are common moths that may be mistaken for the Indian meal moth.

Both are two common non-pest micro lepidopteran species.

Springtails

Springtails (Order Collembola), are not insects at all - they’re hexapods. We come across them fairly regularly and can often be found under rocks, in bait boxes, within leaf litter or anywhere damp conditions are maintained.

As their name suggests they bounce around due to the presence of a spring-like organ (furcula), which is present towards the rear of the abdomen (although a hand lens might be needed to see this).

Springtails are always worth considering if a client is reporting seeing fleas.

Lacewing

Britain is home to around 40 species of lacewings (Order Neuroptera). The green lacewing (Chrysoperla carnea) is probably the most commonly encountered species, especially during winter when they often hibernate inside buildings.

These 10-15mm long, green or brown insects are harmless aphid predators and usually require no control other than being placed outside.

True bugs

True bugs (Order Hemiptera) contain one major pest, the bed bug (Cimex lectularius). However, several other non-pest true bugs can find their way inside.

True bugs are easily identified by their long piercing mouthparts as shown in this common green shield bug (Palomena prasina).

In conclusion

Identification is crucial and the foundation block upon which our IPM plans are built. Identification enables us to carry out the correct treatment, give the right advice, and act professionally and effectively.

Although it might sometimes feel daunting to identify something you’re unfamiliar with, never fear. One of the great things about professional pest control is that there’s always someone to help.

Most distributors and many consultants are more than able and willing to provide identification services, so if in doubt get some support.

Further reading

It’s impossible to list all resources needed to identify all non-pest species. However, here are some starting points:

• The Collins Field Guide to Insects (Michael Chinnery) is a must-have resource
• Mike’s Insect Key – general insect identification with many detailed keys
• Guide to British grasshoppers and Allied Insects (D Ovenden and J Marshall, FSC Publications) – a handy condensed version of these groups
• The Royal Entomological Society (RES) has a range of identification books including keys to many major British beetles including Carabidae and Staphylinidae, lacewings (Neuroptera), booklice (Psocoptera) and a stunning new key to blowflies
• Ball and Morris’s Guide to Britain’s Hoverflies – a great tool for hoverfly identification
• Sterling, Parsons and Lewington’s Field Guide to Micro-moths is also a must-have
• For true bugs, britishbugs.org.uk usually helps me find what I am looking for.

Source: PPC104