AUG 24, 2019 2:16 PM PDT

Aggressive spiders fare better after hurricanes

New research published in the journal Nature Ecology & Evolution details the findings of a study on Anelosimus studiosus, a species of spider which lives along the Gulf and Atlantic coasts of the United States and Mexico. Scientists from McMaster University say that the spiders are evolving because of their continuous exposure to hurricanes.

The damage that hurricanes leave in their wake can change habitats and allow room for opportunistic species to thrive, say the researchers. But exactly which species will survive and thrive is still to be determined.

Lead author Jonathan Pruitt is an evolutionary biologist and Canada 150 Chair in McMaster's Department of Psychology, Neuroscience & Behavior. He and his team looked at the female colonies of Anelosimus studiosus in order to conclude their evolutionary adaptations to extreme weather events.

Anelosimus studiosus is unique in that there are two clear inherited personality traits that colonies can take on: docile and aggressive. According to Science Daily, “The aggressiveness of a colony is determined by the speed and number of attackers that respond to prey, the tendency to cannibalize males and eggs, the vulnerability to infiltration by predatory foreign spiders, among other characteristics. Aggressive colonies, for example, are better at acquiring resources when scarce but are also more prone to infighting when deprived of food for long periods of time or when colonies become overheated.”

The researchers wanted to figure out if a colony’s aggressiveness would benefit or detriment its ability to survive in extreme weather – and, more interestingly, if exposure to extreme weather was selecting for particular spider traits. To gather their data, the researchers had to really get in the thick of it – going to hurricane sites right before and within 48 hours after the landfall of the cyclone. During the hurricane season of 2018, they took samples of 240 colonies and compared them to control sites.

As Pruitt explains, "Tropical cyclones likely impact these stressors by altering the numbers of flying prey and increasing sun exposure from a more open canopy layer. Aggressiveness is passed down through generations in these colonies, from parent to daughter, and is a major factor in their survival and ability to reproduce."

Hurricanes can greatly alter habitats and pave the way for natural selection among species. Photo: Pixabay

The researchers found that following a hurricane, colonies with more aggressive foraging responses produced more egg cases and had more spiderlings survive into early winter. Despite adjusting the data for variables such as storm size, duration, and intensity, the trend remained consistent.

"It is tremendously important to understand the environmental impacts of these 'black swan' weather events on evolution and natural selection," says Pruitt. "As sea levels rise, the incidence of tropical storms will only increase. Now more than ever we need to contend with what the ecological and evolutionary impacts of these storms will be for non-human animals.”

Sources: Nature Ecology & Evolution, Science Daily

About the Author
  • Kathryn is a curious world-traveller interested in the intersection between nature, culture, history, and people. She has worked for environmental education non-profits and is a Spanish/English interpreter.
You May Also Like
JAN 05, 2020
Plants & Animals
JAN 05, 2020
Here's How Reindeer Stay Warm in Freezing Temperatures
Reindeer are some of Winter’s most iconic animals, but have you ever wondered how these spectacular creatures are able to withstand such frigid tempe...
JAN 11, 2020
Earth & The Environment
JAN 11, 2020
The Ganges rising: water levels in the delta
A study published recently in PNAS reports the future of water-level rise in the Ganges-Brahmaputra-Meghna delta. A collaboration of researchers from the C...
JAN 26, 2020
Plants & Animals
JAN 26, 2020
The Life of an Arctic Squirrel
There is no overstating the fact that the Arctic Tundra is a cold and unforgiving place. There are few plants or animals that can survive in this extremely...
JAN 27, 2020
Plants & Animals
JAN 27, 2020
This Octopus Emerges From the Water in Search of Food
Most octopuses live and breathe underwater, just like the vast majority of other marine animals. But this octopus endemic to Australia has a special abilit...
FEB 13, 2020
Earth & The Environment
FEB 13, 2020
Contamination from Industrial Revolution Discovered in Himalayan Glacier
Scientific studies are revealing just how humans have impacted the environment over the past few centuries. Recently, scientists from Ohio State University...
MAR 12, 2020
Earth & The Environment
MAR 12, 2020
Favorite Consumer Goods Drive Deforestation and Increase Malaria Risk
A new study, published this week in Nature Communications and the first of its kind, has linked demand for goods linked to deforestation to a rise in human...
Loading Comments...