How far can spiders ‘fly’?
The autumn spectacle of gossamer on the breeze is a reminder that spiders – particularly our smallest species and the spiderlings of many larger species – can take flight by so-called ‘ballooning’.
Most spiders travel relatively short distances, yet some become pioneers. Their rapid colonisation of isolated volcanic islands and Charles Darwin’s famous observation of thousands of tiny spiders landing on the rigging of The Beagle 100km off the South American coast attest to their long-distance capabilities. Altitudes, too, are impressive, with individuals recorded in the aerial plankton several thousand metres above the Earth.
Ballooning is an energetically cheap form of transport but, whatever the distance travelled, just going with the wind comes at a cost. Only a few aeronauts will survive their risky journeys – a price worth paying only when the chances of colonising pastures new outweigh the risks of overcrowding at home.
To balloon, spiders stand on tiptoe, raise their rear ends and dispense a puff of silk from their spinnerets, which carries them on the breeze.