There are three candidates for the title ‘Daddy Longlegs’. Two of them are arachnids (spiders and their relatives) – first the thin frail-looking long-legged spiders of the Pholcus species which inhabit our outhouses and our bathrooms, and second the related harvestmen (about 25 species in Britain) which are frequently found resting on vegetation around the reserve at St Nicks. However, the Daddy Longlegs name is most popularly (or unpopularly) used of the Cranefly insects – Tipulidae – a family of some 80 British species. Many of these are rare and confined to certain habitats and locations.
In the last few years we have identified around 10 cranefly species at St Nicks, mostly from two families: Tipula and Nephrotoma. Some of these are pictured here, the photos all taken on the reserve. Craneflies could well be the least-loved of all insects, with the possible exception of the common wasp, but craneflies don’t sting or bite. Being weak and clumsy fliers they simply have the annoying habit of getting their long dangly legs entangled in your hair.
So what’s good to say about craneflies? Well, their soil-dwelling larvae, known as leatherjackets, help to aerate your lawn, provide juicy meals for birds such as starlings and rooks, and do a good job of breaking down organic materials in the ground and enriching the soil – but for this they take their wages by chewing the roots of tender garden plants. So it’s swings and roundabouts. An infestation of leatherjackets can severely damage lawns – so much so that in 1935 many thousands of leatherjackets had to be dug out of the hallowed square at Lord’s Cricket Ground, after which the pitch took unaccustomed spin for the rest of the season! There can be as many as 400 leatherjackets in a square metre of ground.
Some otherwise annoying insect species can redeem themselves by being good pollinators, but not the craneflies. Adult craneflies hardly feed at all. Many insects need copious supplies of nectar and pollen to get them into breeding condition, but female craneflies emerge from their pupae fully loaded with mature eggs – as many as 500 each – and immediately try to attract a male to fertilise them so that they can start ovipositing straight away. Their lives are brief, usually just a couple of days – and with their erratic flight and dangly legs they often end up entangled in a spider’s web.
Craneflies are an important part of Britain’s wider ecosystem. Populations of some upland and moorland species of cranefly are under pressure through climate change and the drying out of their peat land habitat. One downside of this has been widespread starvation of Golden Plover chicks in the British uplands, whose main food source is the cranefly. So while we may sometimes find these dangly-legged flies rather annoying, they are a vital part of the food chain and life cycles of other creatures. Their main predators, either as adults or larvae, are birds, moles, frogs, spiders, dragonflies and bats – and they are also the prey of parasitic and predatory wasps.
Annoying they may be, but for a number of reasons craneflies are an important part of the ecology of St Nicks reserve.
All photos were taken at St Nicks