Tiny NZ Spider has the fastest jaws – Expert reaction

A New Zealand spider is the fastest in the world at snapping up prey with its jaws, according to a new study by US scientists.

Image: Trap-jaw spider with its jaws closed. Credit: Hannah Wood
Image: Trap-jaw spider with its jaws closed. Credit: Hannah Wood

The new research, published in Current Biology, explored the the biting mechanism of trap jaw spiders (Mecysmaucheniidae), which are only found in New Zealand and South America.

One particular species of the Zearchaea genus in the trap-jaw family, only found in New Zealand, was so fast the researchers had trouble recording the act with a high-speed camera on its highest setting. The speedy spider was able to snap its jaws shut in just a tenth of a millisecond, a hundred times faster than some other trap jaw spiders.

Read more about the research on Scimex.org.

The SMC collected the following expert commentary.

 Dr Cor Vink, Curator of Natural History, Canterbury Museum

“It is a very interesting finding. The late Ray Forster, New Zealand’s most prolific arachnologist, had hinted at the possibility of this prey capture method due to their unusual peg teeth, which are beside the fangs.

“I can’t imagine why these spiders would have evolved such an elaborate prey capture mechanism. They don’t seem to have specialised in any particular prey and have been reported to feed on a range of insects and spiders.

“It’s interesting to note that the fastest recorded jaw movements were found in an undescribed species in the genus Zearchaea. It is one of a dozen undescribed Mecysmaucheniidae in New Zealand, which shows that there is so much more to learn about our unique and unusual spider fauna.

“There are an estimated 2000 species of spiders in New Zealand, with 95% of them endemic and at least 700 species undescribed.”

Associate Professor Ximena Nelson, School of Biological Sciences, University of Canterbury

“I found this a very interesting paper – and in some ways a very surprising paper. Trap-jaw ants and mantis shrimps are known for extremely fast and powerful movements, but you only have to watch (or be bitten or hit by) these animals to see their speed in the relevant motions.

“Movement speed and power has never been investigated in spiders before – certainly with regards to predation.

“Given the size of the spiders involved (only a few millimetres at most) maybe this is why we have not ‘noticed’ this fast behaviour until this elegant study which combined molecular phylogeny, high-speed video of behaviour, and morphological measurements and 3D reconstruction of structures based on very sensitive technology (micro tomography) on a number of species. However, as someone who works with spiders I am also not surprised to hear about something new and unexpected in this understudied yet extremely varied group of animals.

“It is intriguing that there is such large variation in the predatory strike speed depending on species in this family. As hunters that search for prey without a web, they are likely to rely heavily on their chelicerae (mouthparts) to subdue prey before venom takes effect. However, why some species have speeds that differ by a factor of a hundred is perplexing, and highlights the need to understand their behaviour – in particular, the type of prey that these spiders hunt. They may even bite in defence against predators, which would again be somewhat unusual for animals that typically drop to the ground, remain motionless, or hide to avoid predation.”

Dr Greg Holwell, Senior Lecturer, School of Biological Sciences, University of Auckland, comments:

“This paper shows us the first example of a group of spiders that use a power-amplified predatory strike. Their jaws can strike at prey with more power than would be physically possible using muscle, so some other mechanism must be used.

“Excitingly for New Zealanders, a number of species from this amazing family of spiders are found right here in New Zealand, including a species of Zearchaea with the fastest jaws of all.”

“These are tiny and cryptic spiders, some less than a millimetre long. Although the paper does not discuss what they eat, this lightning strike might allow them to dispatch of their prey efficiently, or possibly tackle larger prey than other spiders their size can manage. I look forward to seeing where this exciting research develops in the future.”