Hunter whose sidelong look can seal a fly's fate

BLINDFOLDING spiders has provided researchers with an insight into the powerful arsenal of eyes the more than 5000 types of jumping spiders rely on to hunt their prey.

By InvestSMART · 13 Jul 2010

By InvestSMART ·
13 Jul 2010

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BLINDFOLDING spiders has provided researchers with an insight into the powerful arsenal of eyes the more than 5000 types of jumping spiders rely on to hunt their prey.

Jumping spiders, the biggest spider family, have four pairs of eyes one central primary pair and three secondary pairs on the side of the head. But a Macquarie University study has found the role of the smaller eyes has been underestimated.

Ximena Nelson, of the university's Centre for the Integrative Study of Animal Behaviour, said jumping spiders relied on vision to hunt insects.

Previously, the three pairs of smaller eyes were given credit only for peripheral vision. But the study, outlined in the Journal of Experimental Biology this month, found they played a greater role.

"We thought it was likely, because they are frontally facing, that they were there for more than just motion detection," Dr Nelson said.

When the main set of eyes was temporarily covered with dental silicon, the spiders were still able to stalk and attack tethered house flies, indicating the three minor pairs of eyes can detect shapes and perceive depth. Their sight was so sensitive they could also see one-pixel moving dots on a side screen.

The findings could prove useful in the field of robotics.

With colleagues, including Daniel Zurek, Dr Nelson replicated the experiment with 52 Servaea vestita jumping spiders, half of them male and half female. The results indicated a gender difference, with females much more responsive to the dot and flies.

"The females live for a long time and lay the eggs and stay with them for three weeks, and the males are, well, walking testosterone bags," Dr Nelson said. "Basically they're bachelors on the prowl. They live for females, not for food."

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Frequently Asked Questions about this Article…

What did the Macquarie University jumping spider vision study find?

The study found that the three smaller pairs of eyes on jumping spiders do far more than just provide peripheral motion detection — they can detect shapes, perceive depth and help spiders stalk and attack prey even when the main central eyes are temporarily covered. The research was published in the Journal of Experimental Biology.

How many eyes do jumping spiders have and what does each pair do?

Jumping spiders have four pairs of eyes: one central primary pair and three secondary pairs on the sides of the head. While the primary eyes were known for detailed vision, the study showed the smaller, frontal-facing secondary eyes also detect shapes, depth and fine motion.

How did researchers test jumping spider vision using dental silicon?

Researchers temporarily covered the spiders' main set of eyes with dental silicon and then observed behaviour. Even with the primary eyes blocked, the spiders could still stalk and attack tethered houseflies and respond to tiny moving dots on a screen, showing the secondary eyes are highly capable.

Which species and how many spiders were used in the experiment?

The experiment used 52 Servaea vestita jumping spiders — half male and half female — to replicate the findings and compare responses between sexes.

Did the study find any gender differences in spider hunting or vision?

Yes. Females were much more responsive to the moving dot stimuli and to flies than males. The researchers noted females live longer and tend to stay with their eggs, while males appear more focused on seeking mates.

How sensitive are jumping spiders to small movements and details?

Very sensitive — the spiders could detect one-pixel moving dots on a side screen, indicating the secondary eyes can pick up extremely small movements and fine visual detail.

Why could jumping spider vision research be important for robotics and technology?

Because the study shows how compact multi-eye systems can detect shapes, depth and tiny motions, these biological insights could inform the design of small, efficient vision systems in robotics and other tech applications.

Who led the study and where was the research published?

The research was led by Ximena Nelson of Macquarie University's Centre for the Integrative Study of Animal Behaviour, with colleagues including Daniel Zurek. The findings appeared in the Journal of Experimental Biology.