This page is about some of the basic techniques for finding and catching carabids. The emphasis is on identifying and getting to know carabids in the field.
You will sometimes see carabids running about in the open, perhaps crossing a path or a patch of bare ground in the sunshine. However, the most reliable way of finding carabids is by looking under stones and logs. You will soon get a feel for the kinds of items that are worth rolling over – a huge, heavy stone or log is often no better than a smaller and lighter one! They mustn’t be too wet and mouldy underneath. Carabids like slightly damp resting places – not too wet and not too dry. Rubbish can be just as good as stones or logs!
Other good places to look are in tussocks – part the tussock and get right into the heart of it. Also look under rosettes of plants, and under mats of creeping vegetation.
Most carabids are largely nocturnal. Most coleopterists are largely diurnal. Going out beetling by torchlight can be very productive, and often gives the night shift of the local constabulary something to laugh about!
A good trowel is an invaluable piece of kit. It has to be said that many coleopterists don’t carry a trowel, but if you are targeting carabids, it is a great help for general rummaging around at the soil surface. Carrying a trowel can draw suspicious stares when visiting reserves with rare plants!
Get your eyes to the ground. The closer you can get your nose to the subject, the more you will find. Kneeling, crawling around on hands and knees and lying down are all good ways of finding carabids. For this reason, looking for carabids on sun-baked dry heaths is more comfortable than in a wetland! A pair of knee-pads from a hardware store or garden centre is a worthwhile investment for added comfort: I swear by them. In wetlands, a pair of waders allows you to kneel down comfortably on muddy ground, in puddles and in shallow water-margins.
What to look for
Although many carabids are small and some of those are also quite brown and inconspicuous, they are all shiny, and most of them run about when disturbed. It won’t be long before you get a search image for shininess and movement. Of course it is not just carabids that are shiny and move, but it’s a start! Take time to stare after you’ve turned a rock over. Some species (e.g. Notiophilus) freeze awhile before sprinting off.
How to catch a carabid
Be firm! Most carabids are surprisingly tough, and you will do no real damage to them by firmly grabbing hold. Immature specimens, which often appear paler and more yellow than normal, do not have fully hardened exoskeletons, and they are easily squashed. Some of the flimsier species also require more delicate handling.
Though mostly good-natured animals, carabids can bite! A few of the larger species have quite sharp and powerful jaws, capable of giving a nip, though not of breaking the skin. The effect of the bite is more of a surprise than actually painful. All species seem to regurgitate a small blob of unpleasant-smelling digestive juices upon anyone who irritates them. The rare bombardier beetle Brachinus crepitans has a more powerful armoury – it ejects an explosive chemical mixture from its posterior, earning it a place in the Guinness Book of Records! A few of the larger British carabids, including Cychrus caraboides and Carabus granulatus, are capable of squirting unpleasant chemicals (acetic acid?) – a few coleopterists have tales of getting an eyeful when examining such a beetle at very close range.
Once caught, it is possible to hold a carabid still by its legs and study it in the field under a hand lens. My big 8x lens gives a really good image in the field, backed up by the 15x to see smaller details.
If you’re going to keep a specimen, drop it into a tube. It sounds so easy, but many a good specimen has missed the tube and been lost in the grass! Keep tubed specimens somewhere where they will not get too hot, not receive direct sunlight (the greenhouse heating effect rapidly kills the beetles) and not get broken: a bum-bag works well, a trouser pocket doesn’t.
A pooter is a device for sucking insects into a tube. You cannot actually inhale the insect, because the mouthpiece is covered by a fine gauze. The big draw-back with a pooter is that it makes field identification very difficult. Still useful for sucking carabids out of crevices, or off very muddy surfaces, or when you just decide to catch absolutely everything that moves. Essential for when you move onto other beetle families.
Many coleopterists carry a white tray (or any other colour) with them and it is a versatile and useful thing to have. Available in pet shops in a range of colours, I think sold as cat litter trays. Few carabids can climb out of one (though many can fly out on hot days) so it can be used to examine live beetles without too much risk of them escaping. Also useful for splashing (a technique for finding beetles at water margins) and for examining sievings.
The basic concept of pitfall trapping is to dig a jar or cup into the ground, level the soil surface flush with the rim of the jar/cup, and leave it for unwitting animals to fall into. Glass jars, with sheer, slippery sides are very effective at preventing the animals from climbing out again. Plastic coffee cups and similar are more popular because they are lighter and less easy to break.
Pitfalls may be left for a few weeks if filled with an inch or two of a suitable preservative (dilute propylene glycol antifreeze (as sold in motor shops, etc.) is the best). You can run dry pitfalls to catch live specimens but they’d need to be somewhere where you can check them daily. Be aware that the catch may drown if it rains, and that if you catch a big predator, it may eat the others – drilling a small hole in the bottom and placing a few pebbles in the pitfall mitigates against both those problems. A rotten apple bait works well for many carabids.
It is amazing how many animals do bumble into pitfall traps – chicken wire covers can help to keep out shrews and amphibians, and prevent dogs/foxes/badgers drinking the contents, but this is still a technique which kills a lot of animals and creates a lot of work identifying everything.
For detailed advice on pitfall trapping, download my Pitfall trapping protocol.
Beginner’s luck is a genuine phenomenon. If you are a beginner, make the most of it! As time goes by, coleopterists settle into using the same old techniques and looking in the same types of places – perhaps not surprisingly, this often means finding the same old species. Beginners often do things that an experienced coleopterist wouldn’t bother with – and come up trumps! So, ignore advice and do your own thing!