Common or vernacular names: the trivial epithet

Common or vernacular naming

It is an innate trait of humans to try to order the world around us. This is the case with all living things. In the 18th Century Carl Linneaus proposed a system of naming species that would allow the relationship between species to be indicated within the name. This binomial system of scientific, or Latin, naming has endured and evolved with strict rules. In the case of insects, the naming of species is overseen by the International Commission on Zoological Nomenclature (ICZN). Under the watchful eye of the ICZN all animal life is ascribed its binomial name and by such is given its place in the tree of life. As taxonomists better understand the boundaries between species and how those species relate to each other, the name may change but always in a manner that is both ordered and traceable.

Common names, also called vernacular names or trivial epithets, have their roots, not in science, but in social history. Trivial epithets are not set down in any international standards, nor are they in any way regulated. They do not come about as a result of any attempt to order or understand life and are entirely chaotic. The use of these trivial epithets in general is to be avoided when recording invertebrates.

As a rule, common names only exist were there has been a need for one person to convey recognition of a plant or animal to another person. A common name may reference a characteristic (e.g. Giant Horntail), habitat (e.g. Alder Wood-wasp) or geographic location of the species (e.g. Southern Hawker). A species will most likely have a common name if it fulfils one of the following criteria:

• The species, or group of similar looking species, is common and frequently seen
• The species, or group of similar looking species, is easily recognisable by eye
• The species, or group of similar looking species, is perceived as a pest or nuisance
• The species, or group of similar looking species, is charismatic, querky or has a specific habit or behaviour

Common names, despite their limitations, are to be valued if only as part of our cultural heritage. For example, woodlice (actually a number of different species) have over 40 common names in Britain alone. These names are part of a rich oral tradition and the name you use will likely indicate where in Britain you grew up. Occasionally, the common name may echo a point of scientific interest. For example, the Turnip Sawfly is the only common name used for Athalia rosae though most records these days would not reveal any association with turnips. The name is an echo of when Athalia rosae was a major pest of turnip crops when they were more widely grown as animal feed. The species came all but extinct in Britain in the early 20th Century before becoming widely distributed again in the latter part of the 20th Century but without the reliance on turnip crops.

More recently, there have been trends in attempting to assign common names to a wider range of species to engage public attention. This dilutes and muddies the oral tradition, though in instances where the species conforms to one of the above rules, there may be some merit in doing so. Perhaps a historically rare species has become common in recent times, or the species is newly arrived in the region and is a potential problem species (e.g. Zig-zag Sawfly). However, where a species is rarely encountered or recognised by the wider public, assigning common names is of little value as they are unlikely to be adopted and their use may even be an inconvenience to entomologists. Of concern is the fact that the same common name can refer to several distinct species. For example, “Birch Sawfly” is widely used to represent both Cimbex femoratus and Nematus septentrionalis. That trivial epithet also ignores the fact that there are 43 sawfly species in Britain and Ireland that feed on birches. Similarly, the same common name may be used in different countries for different species, which is a particular issue when using internet search engines.

One of the arguments put forward in favour of inventing new common names is that scientific names are too hard to remember. Certainly, trying to learn all the scientific names for a taxonomic group, such as the sawflies, in one go would be overwhelming. However, learning an individual species' name as it is encountered is often no more difficult than trying to remember a common name, and a species that is repeatedly encountered and identified soon has its scientific name tripping of the tongue. The invention of new trivial epithets is not to be encouraged. After all, in horticulture, gardeners readily use scientific names, at least in part, with ease (e.g. Rhododendron, Geranium, Salvia). Here the adoption by the hobbyist of the genus as a pseudo-common name is to be applauded.

Below are listed sawfly common names that appear to have become established over time. Only 43 species out of the 550 or so species present here appear to have established common names. Some common names that are peculiar to certain countries are included to illustrate some of the points above.