Hurricanes reshape terrain when they make landfall, but they could also be shaping up something else: animal behavior.
In research published today in Nature, scientists from University of California Santa Barbara, McMaster University in Ontario, and the University of California Davis reported that after hurricanes ravage an area, the aggressive colonies of the spider Anelosimus studiosus tend to get a leg up.
Already, this species, which lives in the Americas along coastal waters, was a bit of a weird one, but some of their behaviors made them an easy—and interesting—study in how spider populations are affected by extreme weather events.
"They're unusual among spiders because they can live in groups of multiple females that cooperate to make a web together, they capture prey like a pride of lions together, and they engage in suicidal alloparental care where they raise each other's offspring and then the last thing they ever do for offspring is to liquefy their own bodies through programmed cell death and allow their young and the young of their sisters to rip them apart," Jonathan Pruitt, a UC-Santa Barbara professor and lead author on the paper, says.
So Studiosus is a social spider, an incredibly rare situation for arachnids—a behavior shared by less than one percent of all spiders. But the spider colonies can run from fairly aggressive to mostly docile, or as Pruitt calls it, the "ramped up wolverine sort of spider society to the meek and mild docile manatee spider society." The "wolverine" groups are a lot more prone to aggression not just toward potential prey, but toward each other.
To study the colonies, Pruitt actually loaded up in his pick-up, dog in tow, to go storm chasing, looking at the populations in coastal states both before and after storms set in, sometimes turning to help from locals when downed trees or powerlines were in the way.
Oddly, they're the ones that seem to thrive after disaster strikes, rather than the more cooperative studiosus cohort. After an area is devastated by a storm, resources become scarce. Aggressive colonies are able to find and attack prey more readily, whereas the more docile, cooperative colonies don't strike as readily — and thus miss out on an important feast in a time of potential famine.
Pruitt isn't sure how a potential increase in extreme storms due to climate change might affect the populations going forward. Partly, it's because the relationship between hurricanes and coastal ecosystems aren't well known. They may well have a relationship not unlike wildfires and forests, as Pruitt says, in which the event is important in maintaining a balance. It may be that, under regular weather patterns, certain species are kept in balance by the storms and could disrupt an ecosystem if storm frequencies increases.
But it's evidence that, for many populations, it may be the aggressive ones that survive these events going forward, with consequences throughout the food chain. This study brings hints that this could be the case, but Pruitt says his fieldwork isn't done yet.
"But certainly it is a big black box that somebody's got to address and I'm going to address for at least a few years until I can no longer drive many thousands of kilometers in my truck," he says.
You Might Also Like