Over 40 years in the development, this new handbook will – for the first time – provide full guidance on taking the identification of beetle larvae to at least family level.
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 of Beetles of the British Isles), 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.
The Handbook's introduction covers the present state of knowledge of beetle families and their larvae in the British Isles and relevant larval identification literature. Summaries are given of general larval morphology, specialised biological aspects (such as hypermetamorphosis and parasitism), habitats and behaviour as aids to identification, pest species and biological control, and collecting, preservation and rearing.
A detailed preliminary key, with 33 couplets, helps users 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. Colour photographs of beetle larvae representing many of the families discussed, and using specimens from the van Emden collection, are provided.
"[...] This has proved to be quite a tricky publication to review. On the one hand, it is a remarkable work that has involved many individuals, some of whom are no longer alive, and a great deal of specialist input. Any serious coleopterist will want it on his or her bookshelf. Whether it will inspire people to undertake further larval studies is another matter, as the subject is likely to appear so complex as to be beyond any but a few specialists. For the more general naturalist or entomologist, the appeal is likely to be more limited. Certainly, there is little possibility of finding a random beetle larva and identifying it even to family level by comparison with the plates and drawings. This is not a criticism of the book, but rather a consequence of the intrinsic difficulty of the subject. There is an opportunity for someone to produce a different work, perhaps online, showing examples of the more distinctive free living larvae to appeal to the more casual observer. Meanwhile, the present authors should be congratulated on completion of this mammoth task."
– Richard Wright, British Wildlife 31(3), February 2020