The Cantharidae are elongate, parallel sided beetles. They are characterised by their soft wing cases that usually lack any noticeable surface structure. There are 41 Species of solider beetle in the UK. The larger species (Subfamilies: Cantharinae & Silinae) are often starkly coloured with blacks, reds and yellows. These colours reminded naturalists of the past of red-jacketed soldiers and this is how this beetle family acquired its English common name.
Many of these larger species have distinctive markings that allow them to be identified in the field or from a photo (see Mark Gurney’s illustrated guide below). However, some species are very difficult to identify from colour alone and, in any case, colour has potential to be variable and cause confusion. For this reason, it is still important to collect specimens and check their structural characters (such as those described in Mike Fitton’s thesis key linked below).
Smaller Cantharidae (subfamily: Malthininae) can be somewhat less brightly coloured. They have shortened, dark coloured wing cases, often with a yellow spot at the tip. These can be more difficult to identify than the larger species, for example, examination of the end of the male abdomen is commonly required to identify specimens of the genus Malthodes. Stephanie Skipp is currently working on new guides to the British Malthininae, so look out for those in the near future.
Larvae: Soft bodied, with a velvety surface and some conspicuous setae. They have sclerotized heads with large mandibles for predating on small insects. They are found on the ground or in dead-wood.
How to find them:
- Adults of many of the larger species can be found on flower heads or in tall vegetation during the summer months. Sweeping and beating are effective methods of catching them.
- The smaller species (Malthininae) are usually found in old trees and can be collected by beating. They have also been known to come to light traps.
- Mark Gurney's visual identification guide to the larger UK soldier beetles (version 3.3, 2019)
- Keith Alexander's tabular field key to larger UK soldier beetles (1973) with annotations by Martin Harvey (2010)
- Mike Fitton's thesis key to most UK soldier beetle species (1986), amended by Brian Eversham (2006)