sciencetech-blog

comments

From their unusual 'rippling' legs to fiendish fangs, spiders strike terror into many people.

But arachnophobes may now have another reason to reach for a glass to trap their nemeses because baby spiders - or spiderlings -  have been caught on camera 'exploding' from the back of their mother.

The bizarre defence mechanism was filmed by Mathew Duncan, of Chula Vista, California, when he captured two three adult spiders in a jar.

Scroll down for video 

The bizarre 'defence mechanism' was filmed when Mathew Duncan, of Chula Vista, California, when he captured two adult spiders in a jar. Here, you can make out the female beneath the aggressor spider (bottom), while her babies scuttle away after 'jumping' from her back

One spider is shown to scuttle aggressively towards the female before flipping her over and grabbing hold of her.

As the fight begins, the female appears to eject her babies from her back, showering them across the jar.

While it may be tempting to think that she has summoned a miniature army to defend her, one expert thinks that the aggressor may have simply torn the sac, which females carry developing spiderlings in on their backs.

Another theory is that the mother was giving her brood the best chance of survival when she was under threat, by releasing them out into the world. 

But it appears it is the spiderlings that have made the 'decision,' not her.

Dr Judith Lock, an expert in behavioural ecology at the University of Southampton, told MailOnline that it looks as if the spiderlings jumped off their mother's backs when she was under threat.

Baby spiders explode out of the carcass of attacked spider

One spider is shown to scuttle aggressively towards the female before seemingly grabbing hold of her (pictured bottom). It is not clear whether the larger spider tears the female's egg sac, whether she deliberately unleashes the tiny spiders in defence, or if, as one expert suggests, the spiderlings escape voluntarily

Some spiders are better mothers than others. Female wolf spiders carry their spiderlings on their backs (pictured) when they have hatched and are among very few species of spiders to do this

A few species of spiders allow their offspring to ride on their backs while they are small. This gives them a better chance of not being eaten.

'The agressor spider flips the mother over. Perhaps the spiderlings recognise a chance in orientation and that's when the jump off,' Dr Lock said.

Craig Walker, arachnid expert at ZSL London Zoo agrees. 

'As the footage is so blurry it does give the impression that she explodes, but of course she is just carrying her brood on her abdomen as do many species of "nomadic" spiders, such as wolf spiders for instance.

'When she is attacked they simply jump off & run for cover.

'Other inverts that carry their young on their backs include scorpions.'

An invertebrate keeper at Bristol Zoo Gardens added: 'The babies scattering is their best chance of survival- not likely to be causing a distraction or an attack. Maternal care methods vary greatly in the world of spiders.' 

Mr Duncan said he had 'no idea' that when he trapped the spiders, one of them was carrying babies on her back.

'So I'm glad I caught it and fed it to the other before I had 20-30 spiders disperse in my home. I would love to know what type of spiders these two are,' he told The Mirror.

If the spider was using a defense mechanism in a bid to ward off her attacker, her 'explosion' of babies is not the only strange defence mechanism unleashed in the natural world.

The hairy frog - also known as the horror frog - breaks its own tow bones when under threat so they stick out through its skin and act as claws. 

Likewise, the Iberian ribbed newt pushes its own rib bones through its skin, before secreting poison through the holes created.

Insects such as the Malaysian ant have poisonous glands which explode when they are threatened, shooting the deadly liquid towards aggressors.

The potato beetle eats poisonous plants to cover itself in toxic faeces, while Cereal leaf beetles encase their poo in a jelly sac, which they carry on their back as protection.

Many creatures have usual defence mechanisms including the cereal leaf beetle (pictured) which encases its poisonous poo in a jelly sac, which it then carries on its back as protection against being eaten