DENVER (AP) — About this time every year, southeastern Colorado towns like La Junta see more visitors looking to glimpse saucer-sized Texas brown tarantulas as they scurry out of their burrows and across fields and roads in search of a mate.
The eight-legged spectacle may not last: Scientists claim climate change, theft, human development are all reducing tarantula population. In fact, fewer emerge each year.
Ryan Jones, a researcher at the Denver Museum of Nature of Science, said that “it’s a noticeable number game.” Comparing photos will show that there are fewer males looking for love.
Maia Holmes, an entomologist said that tarantulas will likely cause a domino effect on the ecosystem if they die. They’ll allow their prey, which includes tarantulas, to multiply, and make it harder for the creatures that eat them to survive.
Holmes said, “Once you cross that line, there is no going back.”
Scientists are unable to provide precise data on the population because there is no dedicated group working on the tarantulas. But Jones, who is currently completing his PhD at the University of Colorado Denver in program integrative systems biology, stated that many people live in that area of Colorado and call the museum every year. These people were people who used not to be able to drive without getting squished by the tarantulas.
That’s a far cry from what Holmes, a former colleague and director of Colorado State University’s Bug Zoo, told Jones. He stated that twenty years ago he would see hundreds around La Junta in a single day, but now, “if you drive all night, you might see 20 or 30,” she said.
Holmes and Jones claimed that the dwindling number of tarantulas is a sign that Colorado’s climate is changing. Holmes stated that climate change is the main reason for fewer tarantulas. This is because warmer temperatures and less rain make for less welcoming environments.
Sergio Henriques (co-chair of the International Union for Conservation of Nature’s Spider and Scorpion Specialist Group) said that arachnids have been shown to be more susceptible to weather changes and changing temperatures. These conditions could lead to different species becoming larger or more aggressive.
Aphonopelma hentzi (the species found in southeastern Colorado) can be found as far south as Texas as well as California. Holmes and Jones noted that the habitats of Aphonopelma hentzi vary across the American South as well as Southwest. It is therefore difficult to predict whether there will be a decrease in population elsewhere.
The tarantula diseases, which can kill them, thrive in warmer climates. Arachnids can be triggered by hot days to escape their burrows, burning precious energy. Holmes stated that they might emerge too late and leave their burrows unprepared for winter.
Holmes stated that water is the key to plants, and prey is what plants lack. They can starve. They can die of dehydration.”
Eric Petersen, NWS meteorologist, stated that the National Weather Service in Pueblo calculates 30-year-averages for temperature and rainfall over the region every decade.
In 2020 they saw a 1.3 degree increase in annual temperatures and a half-inch decrease in rainfall, which indicates a warming or drying trend for the area. Petersen stated that the 30-year average temperature change is about one tenth of an inch.
Petersen stated that 1.3 degrees of change is quite significant. “We live in a climate that only gets 12 to 14 inches of rainfall per year. So a half inch is quite a significant drop.”
Holmes explained that Tarantulas mature in eight years. Scientists can also consider fires, droughts, and heat years, which could result in more teenagers being killed than usual.
She said that eight years ago was a very bad year for fires and a very bad year for drought.
Steve Keefer is a 35-year resident of southeast Colorado and has seen many tarantulas over his lifetime. According to Colorado Parks and Wildlife’s district wildlife manager, there are fewer tarantulas than usual because they appear later in the season and in different places. One person said that they’d seen them as far north as Colorado Springs.
Keefer explained that they usually appeared around Labor Day and only rarely in late August. In recent years, they have been appearing in late September or early October, which Keefer stated would coincide with warmer weather.
— Arachno-mania and sprawl
Here’s where humans come in: The more we build, the more we cut into the habitat in which tarantulas live and burrow, Holmes said. There has been an increase in people taking the tarantulas home and keeping them there, especially after news of their presence spread throughout the country in 2019.
Keefer explained that although it is legal to keep tarantulas as pets, it is illegal to sell them. The male tarantulas, which make up the majority of the tarantula population, won’t survive long if they are kept.
Holmes said that grasshoppers could grow faster and cause more destruction to the local plants if the tarantulas in southeast Colorado go extinct. It is possible that the wasps that feed upon the tarantulas will also go extinct, causing birds, reptiles, mammals, and even coyotes to become hungry, and possibly starve.
However, it’s not clear just how dramatic the ripple effect could potentially be, she explained.
We don’t know the frightening thing. Holmes explained that this is the most frightening thing. “Often times we don’t understand these ecosystem components until they disappear, and then we begin to see things fall apart.”
She added that “extinction is permanent.”