They skulk lankily in the corners of our living rooms at this time of year, and jitter disconcertingly about the bathroom when we are trying to brush our teeth. But are we really seeing a record daddy long legs explosion this year, as some tabloids are claiming?
What is a daddy long legs?
Usually, this is the colloquial name given to a crane fly, those flies that are long of body and much longer of leg, with bendy knees. Their name reflects an affection towards the lanky insects. In Irish they are known as pilib an gheataire, which means skinny Philip, and in Scotland many call them Jenny long legs.
So what is going on?
A news agency claimed that this summer we are facing a “plague of crane flies” due to the weather conditions. This was then picked up and reported as a biblical plague by many tabloids. The writer claimed: “The cool, damp summer has created ideal breeding conditions and they are swarming out of their burrows to take to the air as early autumn approaches. Families leaving windows and doors ajar risk the ‘daddies’ flying in and flitting round lampshades and TV sets.”
Is this true?
Possibly not, according to the experts. Matt Shardlow, of the UK insect charity Buglife, explains that it is almost impossible to know, as crane fly numbers are not yet sufficiently monitored, but there have not so far been unusual amounts of the insects.
He said: “As with most insect abundance stories it is nearly impossible to say anything definite as there is no national abundance monitoring of crane flies, and abundance can be very patchy, so if you live next to a field where the crane flies have done well you will notice dozens, while someone living a few miles away may see many fewer than they are used to seeing, due to local conditions.”
On the whole, insect abundance is declining, but crane flies are thought to have had an OK year, perhaps due to the mild, damp weather.
Shardlow says: “All we can really say is that this is not a bad year for crane flies. Some people are seeing considerable numbers, but no one should be concerned about these big gangly flies as they are completely harmless. Most of the large crane flies people see at this time of year will be common daddy long legs (Tipula paludosa) but there are over 350 species in the UK.”
Should we be happy about them breeding?
Yes. Shardlow says: “Crane flies are an important part of a healthy ecosystem. They are food for birds, bats, hedgehogs and many other animals and some crane flies are highly endangered and conservation priorities in their own right. In particular, there are species associated with specific sorts of wood decay that are very rare indeed – for example, the royal splinter crane fly.”
Are they in trouble?
They may be in future. Like all insects, there are fewer of them than there should be, and that in turn that means less food for the animals that eat them, including amphibians and birds. Lots of rain in summer can be bad for them, as their larvae die in the waterlogged ground. A lack of crane flies is viewed as a factor in the decline of the starling, whose breeding numbers have fallen by more than 50% in 25 years.
Are they dangerous?
A common playground trope is that daddy long legs are extremely venomous, but this is false; they contain no venom, and do not bite anyway. It is thought the fear of their venom comes as a result of them being mixed up with the American recluse spider, which is mildly venomous and is also sometimes nicknamed the daddy long legs.