If the mere mention of an arachnid is enough to make you a little queasy, you can thank your ancestors. 

Researchers have discovered that a fear of spiders is a "survival trait" that may be written into our DNA. The evolutionary response to the eight-legged creatures dates back millennia, to a time when far more spiders represented a poisonous threat.

So what does that mean for those of us who squeak every time we so much as see the shadow of one hairy little spider leg? Well, it actually suggests you have a pretty finely tuned survival instinct.

A research team, led by Joshua New of Columbia University in New York, asked 252 volunteers to study computer screens featuring abstract data and shapes. Researchers found that reactions to spiders were very fast even when their shape was distorted.

New told The Sunday Times: "A number of spider species with potent, vertebratespecific venoms populated Africa long before hominoids and have co-existed there for tens of millions of years.

"Humans were at perennial, unpredictable and significant risk of encountering highly venomous spiders in their ancestral environments.

"Even when not fatal, a black widow spider bite in the ancestral world could leave one incapacitated for days or even weeks, terribly exposed to dangers."