|Staphylinidae Rove Beetles|
| A large family containing more than an quarter of the
British coleoptera. They seem, perhaps understandably, never to have been particularly popular and neither
have they featured usefully in the various guides to beetles that have appeared over the years.
Apart from the most distinctive forms they are difficult, or impossible in many cases, to figure usefully
because there are so many closely similar species and, without an appreciation of the family as a whole and
some very precise guidance, it probably does more harm than good to use such guides for serious
identification. Having said that, colour pictures from general guides (and there are some with excellent anthologies)
can give an idea of the different forms and might also give confidence to an identification made through keys where only
line drawings have been used. It must also be mentioned that, for somebody interested in Coleoptera but approaching
staphs for the first time, they might seem drab and even tedious e.g. having seived an autumn fungi or dung sample
and obtained a few hundred staphs less than 2mm in length, and a good number of them half this length, one needs a certain resolve
in the aspects of dealing them that follow
What follows is our humble effort to help make staphs more accesible. In order to partition the family into maneagable groups, subfamilies and sometimes lower divisions are considered individually.There are many distinctive forms which, when they are learned and (mentally) removed from the list, leave the remainder much easier to appreciate. Notwithstanding this it soon becomes obvious that the problems involved with identification are formidable, and the situation is compounded by there being no comprehensive keys available in English.
At this stage, i.e. early in ones study of the staphs, it is worthwhile learning enough German to be able to make sense of the works of Freude et al ¹, these books give only line drawings but they are lucid and somehow easy to use, they do not repeat the mistake of Joy's Handbook ² where line drawings are proportional to a species size so that the smallest figures, which might have been most useful, become almost useless without a great deal of experience.
Admittedly one needs to be single minded and very determined with the staphs, they are difficult, but every successful identification provides material that can help guide other specimens through the keys. Studying staphs will soon generate a considerable number of identified specimens but in each case they should be taken as far as possible and then labelled and listed for future reference. This will be frustrating but also worthwhile, the secret is to keep on trying to key things out and remain aware of how far your unidentified specimens go, sooner or later things begin to fall into place.
This situation is unfortunate because for those interested in or even (as, sadly, with one of our group ³) excited by dealing with microscopic rove beetles the amount of work needed is very considerable.
Almost, it seems, by way of compensation the syaphs are not difficult to collect. They are found in most situations at most times of the year and just about any collecting technique will produce them. Samples of almost anything organic (sometimes even seaweed) will probably contain at least some; sweeping, beating, light trapping, ?? netting, pit fall trapping etc. etc. will produce them. It would be far easier to list situations where they are not found. Some idea of the ecology of the group is given under the subfamily and species descriptions.
¹ Die Kafer Mitteleuropas, Freude, Harde, Lohse. Vols 4 and 5
² Practical handbook of British beetles, Joy
³ The author's son, one of our junior members, continually provides copious amounts of specimens which the father is expected to set, mount and identify - Webmaster.
| <1-35mm. Generally elongate with short or medium length
elytra leaving at least part of the abdomen visible, in some species of Omaliinae
this may not be obvious. Sutural stria of elytra usually straight but may be modified and overlap e.g.
or Xantholinus spp.. Abdomen eight segmented and usually flexible, variously covered by elytra, terminal
segments may telescope in so care must be taken to appreciate this. Any serious study will necesitate dissection,
the male and female genitalia are often distinctive. Head from broadly transverse to elongate with temples varying
from dilated to contracted to non-existent, sometimes withdrawn into prothorax. Eyes variable but usually entire,
perhaps best developed in Stenus spp., ocelli present in
Omaliinae and Proteininae. Antennae
usually 11 segmented, sometimes 9 or 10, and variable from filiform to broadly thickened or clubbed and variously setose.
Their position of insertion provides the basis of a practical guide to subfamilies. Thorax and abdomen are
variable, from cylindrical to arched or flat, variously sculptured and modified e.g. Omalium,
and Bledius. Legs are generally less variable than other characters; mostly long and/or agile, many species
are capable of rapid movement when disturbed e.g. Ontholestes or Creophilus. Despite the lifestyle of many of the
staphs i.e. burrowing in fungi, dung, carrion etc. the fossorial leg structure of, say, Clivina
or Aphodius is
rarely developed. Tarsi 3,4 or 5 segmented many combinations, it will be useful or even essential to be able to count these (ID Aids)
but this presents a great obstacle in tiny Aleocharinae species, so much so that both Freude and Joy provide practical
help to this group as well as help based on tarsal formulae. Those without experience will find the ID notes useful.
Part of the reason for presenting this site is to show people some of the Coleoptera of our area while providing guidance as to how to make identifications certain. In some groups of staphs this is very difficult and, for this reason, the Aleocharinae are left out of the following discussion covering subfamilies. Apart from this the sequence follows that of the checklist from the Coleopterists website which represents, we trust, the latest ideas in staph phylogeny. In this list the former families Psephalidae and Scaphidiidae are treated as subfamilies of the Staphylinidae and so are considered here. Aleocharinae, which require a rather more detailed approach, will be considered separately following the subfamily discussions.
|32 genera, 181 spp. The position of the antennal insertions will identify the
subfamily. These are clearly visible on the front of the head, often on a transverse prominence or raised tubercles, between the base
of the mandibles. The very variable Aleocharinae also have the antennae dorsally mounted, as opposed to laterally in most other groups,
but they are further back, in line with the anterior margin of the eyes. This sounds good but in practice things can get a bit
ambiguous, on the other hand there is a certain feel for both groups that is soon acquired. Antennae mostly filiform or gradually
thickened, never clubbed. Mandibles usually large, sometimes very much so, and obvious. Head with distinct temples and short
cheeks, clypeus variously punctured. Often dimorphic, generally wider in male. Pronotum quadrate or elongate, without depressions,
from glabrous to completely punctate and pubescent. Legs often long, facilitating rapid movement. Tarsi 5-5-5, claws well
This subfamily contains many large and conspicuous species that will soon become obvious and familiar. They are found in most habitats and at all times of the year and while out recording they cannot escape ones attention. Most move rapidly and some fly readily but nonetheless will be noticed without too much effort. A few have specialised requirements e.g. Velleius dilatatus (Fab.) lives in or around Hornet nests and Remus sericeus Holme is found under decaying seaweed, and many species are very local or rare but to record a wide range of species the following will not disappoint:
Compost heaps. These are very productive during the summer, especially when producing heat. Sieving the outer layers will produce many species of Philonthus and Quedius as well as Xantholinus, Leptacinus and Othius.
Dung. Disturbing dung will send Philonthus and Quedius scattering but may also produce the striking Platydraus stercorarius(Ol.), or the metallic Ontholestes spp. Many other species of both Staphylininae and other subfamilies are in abundance within the dung and so, sooner or later, one will need to bring samples home. This can be unsociable as the author, who regularly extracts dung samples on the kitchen work surface, can testify. But there are limits:
Carrion.Carrion will attract staphs in abundance, as well as many other Coleoptera rarely encountered elswhere, but extracting them must be among the most diabolical of ways to past ones time. Moving a carcass will reveal many large Staphylininae which seem to vanish almost instantly, most scatter into the surrounding vegetation or into the soil or back into the carcass and so a good trowell and a white plastic sheet is a great help. The striking Creophilus maxillosus (L.) is common at carrion especially larger carcasses but moves very fast when disturbed, usually taking flight whilst running or back into any available hole in the carcass. Lifting the carrion onto a sheet or into a sieve can make things much easier but however the sample is examined, the results can be very rewarding. Try and keep any specimens as isolated as possible or you will discover far less specimens at home than you collected in the wild. In general though, it really must be said, pootering, unless using a mechanical pooter which aren't that great, is absolutely out of the question.
Pitfall traps. Will produce them, and in marshy places can be very productive, but if left for any length of time they become somewhat aggressive towards each other so traps must either be examined frequently or contain diluted detergent.
Fungi. Examining fungal fruiting bodies, especially large terrestial species as they begin to die back, can produce Staphylininae in large numbers; a single large rotting bracket fungus from the base of a Beech tree in November (Cassiobury park) produced more than 200 Philonthus fimetarius Grav. and hundreds of Proteinus amomg many others. Berlese extractions throughout the year will produce many Xantholinini and many others.
These methods will produce Staphylininae in abundance but they will turn up by casual searching e.g. under logs or bark will produce Atrecus etc., moving any kind of debris in any situation may reveal them. Sweeping is not that productive but doing so on hot evenings around woodland edges, marshes or dungfields can be rewarding. Many large species can be found sunning on pathways etc. and in the same situations may be found nocturnally.
Joy's 1932 handbook covers the subfamily in a practical way, as ever, and will get most specimens to genus and usually specific level unambiguously - this does not mean you have an ID, but you're getting there. One then needs to check the Coleopterist checklist for changes and additions, of which there are many. Hodge and Jones should be checked for references. Using these sources in conjunction with Lohse (in Freude, 1964 Vol.4 updated in 1989 as Vol.12) is a good way of identifying; much of the work needed in using Lohse's key to genera can be bypassed using Joy (but you need to keep your wits about you), then at specific level one can generally get through the german keys by realising how they are expanding on Joy's work. The line drawings are very helpful and many adaegus figures are given. The Xantholinini are dealt with as a full subfamily, something we need to get used to with staphs; the nomenclature and classification is fairly volatile but this is fair enough; working out the phyllogeny must be the stuff of nightmares. Easing the pain of dealing with the german keys is the fact that they deal with the whole European fauna and so many couplets can be ignored when considering only the Coleopterist list. I must say though that I always feel an element of pushing my luck when confronted with complex and subtle series of adaegi figures eg. Quedius spp. pp.208-209.