Simon Norman's blog

New AIDGAP guide: Adult Caddis (Trichoptera) of Britain and Ireland

Simon Norman — Wed, 20 Jul 2022 12:02:05 +0000

Ian Wallace has co-ordinated the UK National Caddisfly Recording Group for over 40 years. He is the co-author of a new AIDGAP guide to the adult caddis of Britain and Ireland.

The caddisflies (Trichoptera) are a cosmopolitan group of insects whose aquatic larvae are perhaps better known than the moth-like adults. Currently 202 species are known from Britain and Ireland, out of around 1400 species in Europe and over 12,000 worldwide.

Why this guide has been produced

Unfortunately adult caddis have a reputation for being difficult to identify. Although excellent reliable identification guides do exist, they tend to focus on the wing venation and genitalia of preserved specimens. Unlike moths and butterflies, there are no identification guides where comparison with pictures of whole insects is the norm. It frustrates many recorders that they cannot easily name many conspicuous caddis.

This new guide aims to solve this problem. It uses just the visual appearance of the whole living insect, assisted sometimes by magnification no higher than a x 10 hand lens. This enables the identification of adult caddis in Britain and Ireland to a group or often a species.

Development of this guide was inspired by the many naturalists who submit photographs of caddis to websites such as iRecord, iSpot, iNaturalist, the Moth Trap Intruders Facebook group and NatureSpot. All these sites provided a rich bank of material and volunteers for testing. In addition to routine AIDGAP testing, draft versions of the keys were tested at entomological workshops at World Museum, Liverpool in 2020 and 2021.

Getting started with identification

The guide recommends a structured approach to identification.

An initial key enables a caddis to be placed in one of four major groups. This uses simple and reliable body features which can be seen with the naked eye.
Within each major group, we have arranged similar-looking caddis into sub-groups and sections.
The intention is that any live caddis, or photograph of it, can be placed into one of three categories: (a) identified to species, (b) identified to genus, or (c) placed in a small, artificial group.
Unlike moths, the genitalia of caddis are not obscured amongst scales and quite easy to observe using a basic stereo microscope. The specimen will usually have to be killed but a suite of robust species can also be examined under anaesthesia and released, and the book describes the procedure. The genitalia of a large number or caddis are illustrated in the book.

Many recorders support their records with photographs. So we have included things to look out for when taking or viewing photographs. Much of this section has been developed in response to our testing with users. Side-on views tend to be much more useful than views from above. Beware of swamping the insect with uneven flash lighting.

Field survey techniques

Here are four techniques you can use, but there are others.

Light trapping: caddis may be among the first insects to arrive at a light trap (or sheet) as darkness sets in. Many species are crepuscular rather than nocturnal. A trap set next to a river or lake is likely to catch huge numbers.
Beating and sweeping: both of these are traditional insect collecting techniques. Unfortunately beating by itself is largely useless, as caddis readily jump or fly away. But beating into a sweep net can be highly effective. Clumps of ferns by rivers and green ash keys are good places to search.
Searching by eye: caddis can be seen resting on vegetation or other surfaces, though they are often well camouflaged. Bankside vegetation, particularly where is overhangs water, can be a good place to look.
Netting from a swarm: one group of caddis are well known for their gyrating day-time swarms. Vigorously waving a net while rushing into the water may catch some specimens of these insects, and at the very least it will entertain bystanders on the river bank.

The Caddis guide is available to order from the FSC online shop with an Earlybird offer of £16 if ordered by 31 August 2022.

A new guide for identifying freshwater snails

Simon Norman — Sun, 15 Aug 2021 12:33:16 +0000

Ben Rowson is Senior Curator of non-marine molluscs at the National Museum of Wales. He is the co-author of a new AIDGAP guide to the Freshwater Snails of Britain and Ireland.

No one in Britain and Ireland is ever far from freshwater snails. Almost any pond-dipping session, except in the most acidic and polluted waters, will produce at least one snail species. Snails may be small and superficially similar, but their biology and impacts are impressive. They play a vital role in water purification. Some snails indicate unspoilt freshwater habitats, while other host unwelcome parasites, or are nuisance invaders.

Much of what is known about the 50 species in Britain and Ireland depends on accurate identification and recording. This new AIDGAP identification guide aims to make this easier for beginners and experts alike.

What are freshwater snails?

Freshwater snails are gastropod molluscs that live most or all of their lives in fresh water (i.e. water with a salinity below 5 parts per thousand). The families can be lumped into two roughly equal-sized groups.

First are the operculates; snails which carry an operculum, a trapdoor-like plate used to close the shell. Operculates all breathe will a gill and have a snout or proboscis.

Second are the pulmonates, a set of related families which have lost the operculum and also evolved a lung. They breathe air from the surface or carried in a bubble within the shell, which tends to be thin, making them buoyant. Pulmonates include the ram's-horn snails, freshwater limpet and river limpet.

Getting started with identification

An intact, adult shell is all that is needed to identify most of our species. The guide provides three different routes to identification

A simple key to the shells of freshwater snails.
Aimed at beginners, this key directs attention to the most important features one at a time. It divides into two clear sections: flat snails (ram’s-horn snails) and raised snails (plus limpets). We have deliberately minimised the use of technical terms in this particular key.
Comprehensive species accounts and images. This provides essential support for identification, particularly for juveniles and variable species.
Pictorial index showing typical examples.

These three routes can be used separately or together. There are also sections on dissection of snails, plus the identification of juveniles, eggs and spawn. All scientific names and distribution maps are fully up to date.

This guide is part of the FSC’s AIDGAP series (Aids to Identification in Difficult Groups of Animals and Plants). As with all guides in the series, the Freshwater snails AIDGAP underwent extensive testing before publication. Several hundred copies of a preliminary draft (the test version) were sent free of charge to potential users in 2019. The draft was also trialled in identification workshops around Wales. Subsequently we amended the key in the light of feedback from users.

Field survey techniques

Finding snails is often easy, though obtaining a full species list for a water body can be more difficult. Remember that most species are small (under 10mm long). In each water body there will be different microhabitats, each supporting different species. Here are four places to check, but there are many others.

Sample different depths - at least the surface, mid-water (if water weeds are present) and bottom sediment.
Larger stones and cobbles - should be carefully lifted so that both surfaces can be examined.
Leaves and stems of aquatic plants - can produce species such as limpets that may not appear in netted samples.
Flood debris - is often rich in dead shells, a good source of specimens for a reference collection.

A full description of when, where and how to sample different habitats is given in the guide, including the use of nets, biological dredges and sieves.

Habitats and water quality

Sites with the highest diversity of snails (over 10 species) include large lowland ponds, ditches, disused canals and slow rivers. Often these sites have a high diversity of aquatic plants, insects and other invertebrates. So a high diversity of snails is likely to indicate a rich freshwater habitat.

Salinity, pH, hardness and nutrient pollution are all important chemical factors. Very few species tolerate salinity. Indeed salt runoff may make ditches near roads uninhabitable. Neutral water (pH 7) suits all our snails, but most thrive better in alkaline water, as in chalk streams and limestone areas. Others tolerate mildly acidic waters (pH 5-7), but peat bogs are too acid for most. Water hardness (dissolved mineral content) is closely related to pH. Several species are associated with soft and hard water.

Nutrient pollution (phosphates and nitrates) from domestic effluents, faming and industry has become very widespread. Different species are more or less tolerant, and thus can be used as bioindicators.

The new book was produced by Amgueddfa Cymru – National Museum Wales, the Conchological Society of Great Britain and Ireland, and others, with the support of the National Lottery Heritage Fund.

The Freshwater Snails guide is available to order from the FSC website: https://www.field-studies-council.org/shop/publications/freshwater-snails-aidgap

Identifying Blow Flies - Part 1

Simon Norman — Mon, 15 Mar 2021 14:02:25 +0000

Olga Sivell currently studies at the Jill Dando Institute of Security and Crime Science, University College London carrying out research in Forensic Entomology. Her current project is on spatial and temporal distribution of Calliphoridae in Britain. She works at the Natural History Museum, London as a Research Assistant on the Darwin Tree of Life Project.

Why Study Blow Flies?

During the last year I have been putting the finishing touches to a new identification guide to blow flies in Britain. Finally, it was published in March 2021 in the Royal Entomological Society Handbooks series. But why blow flies? And why now?

Despite initial disgust, many people recognise the importance of blow flies:

Indeed, they have a long and interesting cultural history, for example as a symbol of the devil and death in paintings, literature and Christian iconography.
In forensic entomology, a number of species help with crime investigations.
Their larvae feed on carcasses and can be used to estimate the post-mortem interval.
Some blow flies cause myiasis –when larvae feed on live hosts, such as people, sheep (‘sheep-strike’) and other vertebrates.
Others parasitise earthworms or snails.
The larvae of some species are used for cleaning wounds.
They are also important decomposers.
Adult flies pollinate plants while feeding on their flowers.
And of course they can spread disease.

Since 2015 I have been running the Calliphoridae, Polleniidae and Rhiniidae Recording Scheme, with the aim of mapping species distributions and investigating their seasonality. Over that time I have seen a growing interest in flies among the general public. Blow fly records have been gathered from both enthusiasts and professionals, including from iRecord, social media posts and museum collections. Despite all this, many species are still under-recorded in Britain. A major reason for this has been the lack of an up-to-date identification tool.

The Scope of the Blow Flies Handbook

The new book covers British species of calyptrate flies from three families: the Calliphoridae, Polleniidae and Rhiniidae, commonly known as the blow flies. The most common and easily recognisable are bluebottles (Calliphora spp.) and greenbottles (Lucilia spp.). The metallic appearance of the majority of blow flies means they are readily distinguished from other flies. However, because there are a few other metallic calyptrate flies, especially tachinids and muscids, I have included a guide to common look-alikes. This section also covers blow flies that are not metallic and might be confused with flies from different families. Collectively the blow flies are a small and manageable group.

Only 30 species of Calliphoridae have been recorded in Britain and Ireland, 8 species of Polleniidae and 1 species of Rhiniidae. There have been significant taxonomic changes in the last decade. As a result, the existing identification guides that cover this group (such as the blowflies Naturalists’ Handbook by Zakaria Erzinçlioğlu, 1996) are out of date. Biological recorders and enthusiasts should find a good list of blow flies within their local area. Since many species are seasonal and some are active in winter, there is the potential to study these flies all year round. Although specimen preparation such as genitalia extraction is sometimes necessary, I have avoided more complicated characters where possible in the key. In fact, some species can be identified and recorded from a good photograph (see below). But unavoidably for other species, some of the characters that need to be examined are too small to see on a photograph, such as the coxopleural streak and some bristles. I check all submitted records meticulously to maintain the high quality of data collected by the Recording Scheme.

Blow fly species that can be verified through photographs

Calliphora vicina. A common and widespread bluebottle, especially in urban sites, found all year round (but not ‘on the wing’ when it is very cold). The anterior thoracic spiracle is pale yellow to orange, while the basicosta is pale.

Calliphora vomitoria. Another common and widespread bluebottle, especially in non-urban habitats like woodland, found all year round (except when it is very cold!). Look for the ‘ginger beard’: orange hairs on the gena and postgena.

Cynomya mortuorum. A widely distributed fly, but more common in Scotland and northern England (from Leeds northwards). Look for the strikingly golden yellow ‘face’: golden yellow frons, prafacialia and gena.

Pollenia amentaria. Common, in meadows, marshes and uplands. Look for crinkly yellow hairs on the thorax and the black abdomen without a dusting pattern.

Lucilia richardsi. A greenbottle, common in England and Wales as far north as County Durham. Attracted to carrion, breeding on dead birds and small mammals. Look for the pale basicosta, which varies from creamy-white to orange and 2-3 anterodorsal bristles on second tibia.

Stomorhina lunata. Superficially similar to a hoverfly, and common in southern, eastern and central Britain. Abdomen with a yellow pattern, and a thorax with 3 dark stripes. Look for the lower part of the face, which is both shiny and strongly protruding. Live specimens have stripy eyes, rather like some of the horseflies.

Records of blow flies can be submitted to iRecord.

The guide is available to order from the FSC website: https://www.field-studies-council.org/shop/publications/blow-flies/

A new identification guide to British beetle larvae

Simon Norman — Mon, 08 Jul 2019 12:10:32 +0000

Over 40 years in development, the RES Handbook to British Coleoptera larva was published on 1 August 2019. You can order the book online from the FSC website.

For the first time, the Handbook will provide full guidance on taking the identification of beetle larvae to at least family level. At the same time, by keying to genus where possible and including extensive references to other published works, the Handbook will guide the user to more precise identifications.

Why was a new guide needed?

The order Coleoptera is one of the largest groups of animals, with around 400,000 species currently described world-wide. Although relatively poor in species (4072 according to Andrew Duff's 2012 checklist), the British beetle fauna is reasonably diverse at family level. 103 of approximately 176 world families are represented in Great Britain.

Like butterflies and moths, beetles undergo complete metamorphosis, with four distinct life-stages: egg, larva, pupa and adult.

Most beetles spend the majority of their lives as larvae. The longest recorded larval development, more than 50 years, is for a North American wood-feeding buprestid with an adult life of just a few weeks.

Arguably it's at this larval stage where beetles make their greatest ecological impact, since larvae are primarily occupied with feeding.

Despite the importance of the three immature life-stages, most identification guides only cover the adults. For more than 100 genera in Britain, especially in the families Staphylinidae, Leiodidae and Histeridae, the larvae stages are still effectively unknown. The only way to identify many specimens has been to rear the larvae to adults.

Finding beetle larvae

Many biological recorders will have caught beetle larvae, perhaps in pitfall traps, through leaf litter sieving and in kick-samples of freshwater gravels, or in decaying wood, flowers and seed cases, or even in galls and mines.

In a number of taxa, larvae are much more likely to be encountered than the adults, especially when the adults are short-lived and seasonal. For example, the distinctive velvety larvae of the Cantharidae (soldier beetles) may be found throughout the year, sometimes in numbers in leaf litter or pitfall traps, while the adults only appear for a restricted time during the warm months.

Some adults are elusive and unlikely to be casually collected. A good example is the click beetle Stenagostus rhombeus, not uncommonly found as larvae in tree stumps and decaying logs in wooded parts of southern England, but with its nocturnally active adults rarely seen. Guidance on specimen preparation is included in the Handbook.

Identifying beetle larvae

First of all, how can you be sure that your specimen is actually a beetle larva? To help answer this critical question, the Handbook features a detailed preliminary key, with 33 couplets, to distinguish Coleoptera larvae from other immature insects.

This leads to the main key, with 163 couplets, to the 103 families and many of the subfamilies. To keep the key simple, several of the larger families key out in more than one place. The second half of the Handbook is a systematic survey of the biology of each family.

The RES Handbook to British Coleoptera larva is due for publication on 1 August 2019. You can order the book online for a special pre-publication discounted price at FSC website.

New AIDGAP test version for 2015: The Mosquitoes (Culicidae) of Britain and Ireland

Simon Norman — Tue, 03 Mar 2015 11:00:27 +0000

FSC Publications have been working with Clare Strode and Thom Dallimore at Edge Hill University to develop a new AIDGAP guide to the mosquitoes of Great Britain and Ireland. This will be ready for AIDGAP testing from spring 2015.

If you have not been involved in AIDGAP testing, and would like to do so in the future, you can register on the FSC website.

Why mosquitoes? As well as interest to the biological recording community, identification of mosquitoes has a real applied value in the fields of human and animal health. Although some identification materials are available, an up-to-date treatment of the approximately 34 British and Irish species would be helpful.

There is growing interest in the European mosquito fauna because of the increased threat of mosquito-borne diseases as the range of some species expands northwards. Although nothing mosquito-borne has reared its head in the UK so far, it may only be a matter of time.

As part of their research, the authors have been working with the Liverpool Port Authorities (LPA) to prevent potentially deadly diseases entering the UK. Disease vectors including mosquitoes may inadvertently be imported through shipping vessels in the UK. Liverpool has, of course, long been a major port; currently the UK’s sixth highest in annual freight tonnage (behind Immingham, London, Milford Haven, Southampton and Teesside). Working together, Edge Hill and the LPA are designing an efficient method for the surveillance of mosquitoes that could be carrying diseases such as dengue fever, malaria, West Nile virus and chikungunya.

Watch this space - The test version of ‘Mosquitoes’ will be available later this year.

Winter trees: From AIDGAP test version to final book

Simon Norman — Tue, 22 Oct 2013 00:00:00 +0000

This blog was migrated to this website on 17/02/15 from the previous Tomorrow's Biodiversity scratchpad website.

The accurate identification of specimens is an important part of many forms of biological fieldwork. Although popular groups, such as birds and butterflies, are well served with identification guides, other groups are relatively neglected. Back in the 1970s, the Field Studies Council initiated the AIDGAP project, to work towards producing identification materials for these negelected groups. In many cases, the difficulty lay in the absence of a simple and accurate key, and not in any insuperable taxonomic problems.

A significant feature of all new AIDGAP guides is the extent to which they are tested before final publication. In addition to routine editing and refereeing by experts, the guides are subject to extensive field tests. Copies of the preliminary draft (the AIDGAP Test Version) are circulated to a wide range of potential users, including students, amateur naturalists and research workers. In the past, printed copies were circulated; today a freely downloadable pdf is usually made available. If you have not been involved in AIDGAP testing, and would like to do so in the future, there is more information about AIDGAP testers at the FSC website.

Feedback, both written and verbal, is passed to the FSC’s AIDGAP co-ordinator, and is used to generate an anonymised report to the authors of the outcomes of AIDGAP testing. One of the strengths of the anonymised testing process is that testers should not feel reluctant, perhaps out of reasons of politeness, to submit critical feedback where they feel that this is justified. The authors are asked to amend the guide in the light of this feedback before final publication.

Winter trees: a photographic guide to common trees and shrubs

The latest guide to pass along the AIDGAP conveyor belt is Winter trees: a photographic guide to common trees and shrubs by Dominic Price and Leif Bersweden. Tested over autumn and winter 2012/3, the final book is printed and available for October 2013; a fantastic achievement by the authors.

As usual, testers came from a wide range of backgrounds, from interested beginners to professional botanists, and included teaching staff and others from within the FSC. In common with almost all AIDGAP guides at this stage, the Test Version attracted a wide range of responses, some were very enthusiastic, others had concerns as they felt there were problems with some sections of the guide. Interestingly the sections that testers had trouble with were also sections that the authors had become concerned about during their own testing and fieldwork.

A common observation was that the new guide was an unsatisfactory replacement for the existing AIDGAP dichotomous key by Panter & May (A guide to the identification of deciduous broad-leaved trees and shrubs in winter, 2000). It’s probably worth stressing here that the new guide was never intended to replace the older key – which remains in print, and this gave us a valuable lesson for the future; always make it clear to testers the intended level of the guide and whether it is in an addition to the range or a replacement for an existing book. This was intended to be an intermediate ‘stepping stone’ helping people first trying to identify in winter and those with a general curiosity, so had to be suitable for those with little or no experience of using keys, However the range of photographs will be a useful additional support for many fieldworkers.

There were two routes into the guide – photographic bud galleries and a dichotomous key. Both these routes then directed testers to the illustrated species accounts to confirm (or otherwise) their identification. The illustrated species accounts were generally felt to be pitched at the right level and there was widespread feeling that the photograph section was a good idea. As one reviewer wrote:

‘The whole concept is excellent and the genera/species accounts are very good for beginners… Almost all beginners will use the very good photo gallery for ID.'

The area that caused most problems was the dichotomous key. Although the authors had tried to create an accessible key for beginners, problems in bud and twig variability and lack of clear characters for some species had made this difficult. However, there was a general feeling that the key was basically redundant as most beginners would use the bud galleries.

So what is in the final book?

As the feedback had showed that most people were using the photo galleries of buds for initial identification this has become the main route through the guide. Users start at the gallery of bud photographs, grouped into opposite and alternate buds and are then directed to the photographic species accounts that make up the majority of the book. In addition there are a few pages of photographs and key identification features of confusable species, such as Beech and Hornbeam.

Each species (or genus) has a photographic species accounts with text outlining the overall characteristics, twig features, bud characteristics and bark, supported by photographs of each. 36 species or groups of species are covered, including the commoner species and a few rarer examples.

To order the book, visit Winter trees: a photographic guide to common trees and shrubs on the FSC website.