Can a spider stay underwater for a long time without drowning? It’s a somewhat unusual tactic for a spider, but there it is. A team of scientists from Binghamton University, the Amazon Conservatory of Tropical Studies, California State University in Sacramento, and the University of Aveiro has documented the prolonged use of underwater refuge (more than 30 minutes) by the species Trechalea extensive in the face of a threat perceived by the arachnid.
For any spider, diving underwater can be deadly, but this species seems to have devised a foolproof way to avoid having to come out for air: it uses a film of air to hide. According to experts, the hairs that cover its body would be ideal for maintaining this film of air on its body , also helping to prevent thermal loss under water, while protecting it from getting wet or getting water into the respiratory organs. of the arachnid.
Ducks to water
“For many species, getting wet and cold is almost as risky for survival as dealing with their predators,” says Lindsey Swierk, research assistant professor of biological sciences at Binghamton University and co-author of the paper published in the journal Ethology . ” Trechalea spiders weren’t known to hide underwater from threats before, and certainly not for that long.”
Scientists suspected this because spiders are air-breathing creatures and are not adapted to the cold running water in which the spider submerges. In total, they observed that he remained underwater for up to 32 minutes. Quite a record.
An air shield?
“The film of air surrounding the spider appears to be held down by hydrophobic hairs that cover the entire surface of the spider’s body,” Swierk said. “It is so complete that the chandelier almost looks like it has been dipped in silver .”
unusual behavior
Biologists observed a large tropical spider ( Trechalea extensive ) fleeing from humans and hiding underwater. Until now, it was unknown that this species used water to escape. Therefore, this observation provides a new perspective on how species can deal with the problem of finding shelter under water.
It’s clear that these spiders, and any animal that hides from predators in general, have to go to great lengths to manage risk and find creative ways to survive.
“For some species, that means leaving territory or mates unprotected, or perhaps expending stored energy on a run. In this species, the potential risks of the use of underwater refuges can include lack of breathing and loss of body heat”, the experts continue.
Upcoming observations of the spider’s unusual behavior could help scientists better understand how the animals deal with predators. Unfortunately for the enterprising spider, when it emerged, after those more than thirty minutes, the researchers managed to capture it for their investigation.
“There are many more questions to delve into from this first observation,” the authors conclude.
Referencia: Lindsey Swierk, Macy Petrula, Patricia Esquete. Diving behavior in a Neotropical spider ( Trechalea extensa ) as a potential antipredator tactic. Ethology, 2022; 128 (6): 508 DOI: 10.1111/eth.13281
