A regular evening visitor to houses and gardens across the land, the ubiquitous ‘Daddy Longlegs’ must surely be one of Britain’s most instantly recognisable insects. With a life cycle that relies on damp grassy places, craneflies are particularly plentiful in wetland areas, too, and their presence is often a good indicator of healthy habitat.
ID: thin bodied and gangly of leg, you might think once you’ve seen one cranefly, you’ve seen them all. However, our shores are home to over 300 species, of varying shapes and sizes, many of which you won’t have witnessed dancing frantically around the light bulb in your kitchen! On the Weald Moors, the most common groups you’re likely to encounter are True (Tipulidae) and Limonid (Limoniidae) craneflies, whose family members make up the overwhelming percentage of species found in Britain. In many instances, a reliable method of telling them apart is the position of their wings at rest. Limonids tend to hold theirs swept back, while True craneflies are held out at right angles to the body.
Craneflies belong to the order of true flies (Diptera), a collection of insects characterised by having two wings. If you’re able to look a little closer, you’ll also find what looks like a tiny table tennis bat behind each — these are the ‘halteres’, which help the insect to keep balance during flight. While craneflies are distinguished by their elongated appearance, females tend to have larger abdomens that conclude in a pointed ovipositor (the male abdomen being rounded or club-shaped). Reminiscent of a stinger, it is in fact a vital component of egg-laying, a process that is also aided by the long, delicate legs that act like a tripod as the procedure takes place.
Craneflies, Wetlands and the Cycle of Life: while some cranefly larvae are aquatic or saproxylic (dependent on dead or dying wood), for many species, damp earth is an essential part of the recipe for existence. Consequently, the permanently moist peatland soils of the Weald Moors are a particularly desirable location for them. The typical cycle of life for most species will find their larvae — known as ‘leatherjackets’, owing to their thick-skinned appearance — developing just beneath the soil surface between autumn and spring. It is here they feed on decaying plant material and the roots of grasses, which can result in a characteristic yellowing of the sward above ground. Typically, the larvae begin to pupate around midsummer, hatching in late July and August. At this stage of their development, they are vulnerable to ‘drying-out’, so the transition to adulthood often occurs at night or under heavy cloud after rainfall.
This is a time when Starlings, for whom leatherjackets are a staple food, and other farmland birds may be observed pecking the ground en masse for the pupal cases that facilitate this perilous journey (try looking out for these tiny vessels sticking out of the soil in damp pasture following wet weather). Adult craneflies are on the wing for little over two weeks, spending practically all of their time in the pursuit of sex — to the extent that they rarely take nectar (although Hogweed is a typical food plant). In fact, females will begin the process of laying their eggs just 24 hours after taking flight, with their larvae hatching around two weeks later to begin the process all over again.
On the Weald Moors: craneflies are on the wing across the Weald Moors from spring until autumn, with numbers generally peaking in September. Although they are predominantly nocturnal, a daytime walk across damp pastures (especially those fields with a short sward), alongside a grassy wayside verge, or beside a hedgerow or woodland edge should reveal a ground level glimpse of at least one or two species. Many craneflies are associated with particular types of habitat, such as grassland, marsh, woodland or flowing water. In individual cases, the reasons for these connections are unclear but it is thought they may be linked to the specialised dietary requirements of their larvae. Marsh and wet woodland are typically the most common habitat features in which cranefly thrive, and a good site might contain as many as forty species. Owing to the widespread drainage of the Nineteenth Century, pristine sites of this nature are no longer present on the moorlands but heading to places such as Wall Farm, Kynnersley Drive or the well wooded enclaves of the Humbers should pay dividends.
A Pinsticker’s Guide: here is a short list of some of the craneflies that have been recorded on the moorlands, many of which do not have a common name. Their habitat preferences are also noted, along with some features that may allow you to recognise them. Bare in mind, though, that correctly identifying many species will rely on the trained eye of an experienced entomologist!