This September, spider frights are up! Whether one makes a sudden dash across your floors or joins you in the bathtub, there’s no denying that they’re everywhere. This is happening because we’re in the thick of mating season, where spider activity goes through the roof as males search for females.
Spiders crawl in through any small gap they can find, whether it’s a crack in your windowsill or a slight gap under your door. But did you know that’s not the only way spiders get around? Turns out, they can also ‘fly’ into our homes by a method called ballooning.
That sounds as terrifying as it is intriguing, so I spoke to Adam Hart, professor of conservation ecology at the University of Gloucestershire, to find out what it involves and what can be done to stop them from making our home the destination.
What is ballooning?
‘Spiders really can travel through the air using a behaviour known as ballooning, but I wouldn't want people imagining large house spiders flying through their bedroom windows!’ Adam stresses. ‘Ballooning is particularly associated with tiny spiderlings and small species such as money spiders, and it’s a completely natural way for them to disperse.
‘The spider produces the silk itself. It typically climbs on to an exposed point, raises its abdomen and releases extremely fine strands of silk from its spinnerets. Air currents catch the silk and can eventually lift the spider from the surface and carry it away. Some spiders can travel considerable distances this way.
‘“Flying” is therefore a slightly misleading description because the spider isn’t flying under its own power – it has no wings. I sometimes think “kiting” gives a better mental picture: a tiny spider being carried through the air attached to strands of silk.’
So we don’t need to worry about the larger house spiders travelling into our homes by way of ballooning. This soaring technique is exclusive to the tiny species of spider we’re less likely to be startled by. Having said that, spider mating season is as applicable to money spiders as it is to house spiders, so there will be more ‘ballooning’ at this time of year.
How to stop spiders from ballooning in through windows
The obvious solution to preventing ballooning spiders from entering your home is to keep windows and doors shut. However, Adam emphasises that these spiders are no real threat.
‘A ballooning spider could certainly drift through an open window or door, so technically spiders really can arrive in a house through the air. But I wouldn’t regard this as a problem people need to take special precautions against. The spiders involved are generally tiny and harmless, and most will probably pass completely unnoticed.
‘It’s also quite separate from the large house spiders people are noticing at the moment. Those spiders aren’t ballooning into our homes. At this time of year, adult male house spiders become much more conspicuous because they’re wandering around searching for females.’
So you really needn’t fear these tiny ballooning spiders. In fact, they can do some good for your home by eating the real pests, such as fruit flies, aphids and mites. With that in mind, you might want to leave windows and doors wipe open for a free pest-control service! But, if these tiny spiders aren’t to your liking, Adam has some advice here too.
‘If somebody genuinely wants to minimise spiders and other invertebrates entering through open windows, a fine insect screen is the obvious physical barrier. But I certainly wouldn't recommend keeping windows closed because of ballooning spiders. They’re a fascinating example of spider dispersal rather than something householders need to worry about.’
Ballooning spiders serve a purpose in the ecosystem just like all spiders, so don’t kill it if one finds its way in. Instead, take it outside and release it, using the cup and card technique if necessary. There's always the option of using a spider catcher for the bigger ones too!
