Handbooks for the Identification of British Insects Volume 9 Part B
When sweeping a net in woodlands or similar habitats it is very difficult not to find fungus gnats. They are a large and abundant group of Diptera with 574 species in Britain, but until now one of the prominent components of the fungus gnat fauna has been near impossible to identify without recourse to a disparate and difficult literature. With this much awaited handbook, this last and intractable group, the Mycetophilinae, can be identified, opening up the way to understanding their distribution and biology.
In the past, all fungus gnats were placed in the ‘Mycetophilidae’ but now it is considered a group of families – the Bolitophilidae, Diadociidae, Ditomyiidae, Keroplatidae and the very much larger Mycetophilidae. The last RES handbook on fungus gnats (Hutson et al, 1980, available as a free download from the RES website) covered the smaller families above and part of the Mycetophilidae leaving the largest subfamily, the Mycetophilinae (334 species), which is treated here.
The handbook begins by succinctly summarising previous works on the British fungus gnat fauna, their phylogeny, relationship to the continental European fauna and recording their distribution. The author has just about single-handedly been recording fungus gnats for decades, which no doubt is the basis of the comprehensive nature of this handbook. The introduction concludes with a thorough explanation of the morphology required for identification with both diagrams and, importantly, labelled photographs.
The Mycetophilinae, as far as is known, are almost exclusively associated with fungus fruiting bodies and as we are told “the larval biology of many species (including around half of the species covered in this handbook) is unknown and there is plenty of scope for new observations… even many common species have yet to be reared”. The systematic list of fungal hosts of mycetophilines is comprehensive, giving details of which species have been reared as well as which fungi have yielded fungus gnats. The ability to know what has and what remains to be discovered makes the publication of this book so exciting.
As a prequel to the main keys, the families of fungus gnats are briefly discussed, including diagnostic features and typical habitus. The main keys begin with subfamilies of the Mycetophilidae before diving into the tribes and genera of the Mycetophilinae and finally to all 334 species of the subfamily. In general, more than one character is used in a couplet, an important feature where, of necessity, in some parts of the key it can long and sometimes complex (e.g., in the genus Mycetophila). The keys work, though often much to-ing and fro-ing is required to check morphological terms and illustrations.
Following the key to genera, accounts of each genus cover diagnostic features, distinctive morphology, number of species in Britain and continental Europe. Keys to species within the genus are followed by succinct species notes, covering distribution, habitat, and rearing records, for Britain and elsewhere in Europe (with references).
Without doubt one of the highlights of this book is the remarkable photographs of wings and genitalia by Janet Graham, often based on preparations by Andrew Graham. Together with the high quality of the printing, the extraordinary clarity and depth of field of the photographs makes comparison to unidentified specimens very much easier than is usual in books of this type.
Finally, the index covers gnat species in the handbook, rather than other topics, such as morphology, habitats or host records which are found in the relevant sections. The book is very well produced in a robust paperback binding by the Field Studies Council.
The price of the book is confusing. When it was published in June 2022 it was £38.50 from the RES. On the CABI website, the new partner publisher, it is now £60. On the RES website it is £60 but it indicates that Members and Fellows can obtain a 50% discount but give no simple indication how this discount can be applied (nor does the CABI website). On a leading bookseller’s website, it is ‘discounted’ to £55. It is also available as an ebook (£60, not accessed). If you can get it for £30 this is a remarkable bargain.
A revision of the taxa covered in Hutson et al. (1980) is currently being prepared by Peter Chandler and will no doubt be as useful and remarkable as this book.
This handbook is a real tour de force and a credit to the Society. It sets a very high standard and will inevitably be well thumbed by field biologists and enthusiastic dipterists alike.
Editor’s note: This book is indeed available to RES Members and Fellows for £30. The discount code to be entered on the CABI website can be found on the member resources page. Full info here https://bit.ly/RESFungusGnats
