Bug-eyed monster

There is a rather frightening bug-eyed monster lurking just outside of my back door. With strong biting mouthparts and huge forward-facing eyes, this monster is beautifully adapted for hunting prey, actively seeking out victims with a quick darting lunge. Fortunately, for me, it is only a few millimetres in length and, consequently, would only be truly frightening if I happened to be of similar size!

The creature in question is a ground beetle known as Notiophilus biguttatus. Unfortunately, like many of its kind, it lacks an English name (though ‘Common Springtail Stalker’ has been suggested). As the name implies, this is a not uncommon species, found across a range of habitats (including gardens), where it specialises in feeding on springtails, mites and other small animals. Springtails are the favoured prey though; these are those tiny wingless insects that exist in huge numbers within leaf litter, where they feed on fungi and decaying plant material. As their name suggests, springtails have a rather useful adaptation, an organ known as the furcula. This is held, clicked into place beneath the body. If danger threatens, the catch is slipped and the furcula slams down into the ground propelling the tiny creature up into the air and away from immediate danger. The only downsides of this strategy are that the springtail has no control over where it lands and that the furcula takes a little while to reset before it can be used again.

I am fortunate in having a stereo-microscope that enables me to take a detailed and close-up look at such small organisms. At times-forty magnification, the brutal power of the common springtail stalker can be see. The compound eyes dominate the front of the face, ideally adapted to detect movement and to determine the distance between the beetle and its prey. Between these eyes are a series of furrows, the exoskeleton of the beetle rippling up in a pattern characteristic of the species; there are seven other British species of springtail stalker, each typically with a different pattern of furrows. Then there are the biting mouthparts, able to slice through the soft-bodied springtails once caught. Behind the head and thorax is the abdomen; like other ground beetles this is covered with a pair of hardened wing-cases, though unlike many other beetles, the species is actually flightless. The whole body is carried on three pairs of jointed legs, able to propel the beetle across the ground with an astonishing turn of speed. Seen without magnification this beetle may easily be dismissed as an ant scurrying across the ground. However, invest in a magnifying glass and take a closer look. You will soon discover that it is something of a jungle out there.