The Courier & Advertiser (Angus and Dundee)
Study suggests moths alter taste as defence
Some moths do not bother to flee from predators because they make themselves taste disgusting, a new study suggests.
Moths were observed to see if they used ducking and diving tactics, while bats were watched to see if they consumed the bugs or spat them out.
Researchers say their findings show the risks and rewards of antipredator strategies where mistakes can inevitably mean death.
Many creatures in the animal kingdom have evolved tactics to evade and deter potential predators.
In moths, this includes chemical defences that make them less appetising, ultrasonic hearing to hear bats approaching and midflight swoops and dives.
Dr Nicolas Dowdy, of the Milwaukee Public Museum and
Wake Forest University in the US, noticed unusual behaviour in certain species of tiger moths.
They seemed to be relatively relaxed when attacked by predatory bats, prompting scientists to investigate the reasons behind this casual behaviour.
They hypothesised that nonchalant moths have evolved chemical defences that made them unpalatable, meaning they have less motivation to evade bats than their more delicious moth counterparts.
In order to test this theory the researchers collected five different species of tiger moths and then released them in an outdoor “flight arena” at night, where wild bats would frequently swoop in to feed.
Dr Dowdy said: “Strikingly, we observed that moths with weak or no chemical defences often dive away to escape bat attacks.
“However, moths with more potent chemical defences are more ‘nonchalant’, performing evasive manoeuvres less often.”
According to the study, published in the Frontiers in Ecology and Evolution journal, this correlation allowed the researchers to predict the evasive or nonchalant behaviour of the moths based on their palatability.