SANTA BARBARA COUNTY, Calif. (KEYT) – A three-inch long Joro spider (Trichonephila clavata) was spotted at a local Santa Barbara County business this fall.
The potentially invasive species is harmless to humans, but this is the first time it has been spotted west of the Great Plains region shared the Santa Barbara Museum of Natural History Tuesday.
The captured female Joro Spider amongst Coast Live Oak leaves. Image courtesy of the Santa Barbara Museum of Natural History.
According to the Santa Barbara Museum of Natural History, the single female spider is believed to have hitched a ride on plants shipped from another part of the country and was found near where shipments of plants are received.
Collective nursery plants, such as cut flowers and potted plants, were the second-highest valued, non-cannabis crop in Santa Barbara County last year.
"Insects and arachnids—being very small and easy to overlook—are easily transported unintentionally," explained the Santa Barbara Museum of Natural History's Schlinger Chair of Entomology Dr. Alex Harman. "In addition to things like spiders that are on vegetation, there can be insects inside wood. It’s not uncommon for wood-boring insects to be transported inside wooden pallets, furniture, or firewood. Sometimes wood-boring beetle larvae can take over a decade to mature, so those insects can pop out in a new area long after the wood was moved."
Dr. Alex Harman with a Blue Morpho butterfly at the Butterflies Alive! exhibit. Image courtesy of the Santa Barbara Museum of Natural History.
Dr. Harman mentioned invasive beetles because while spiders may appear scarier, the impact by invasive beetles can be substantially more pronounced as spiders tend to be more generalist hunters while beetles, such as the Emerald Ash Borer, are more specialized in their prey selection.
"If you think of the Emerald Ash Borer, it feeds on ash trees," explained Dr. Harman. "You can measure that the ash trees are dying because of this beetle. But spiders are generalists, mostly eating small insects trapped in their web, and it’s a lot harder to measure an overall decline in their insect prey, or a decline in native spiders getting outcompeted by invasive spiders."
The distinctively yellow, grey, and black spider is an orbweaver native to east Asia that could potential compete with indigenous orbweavers.
Joro spiders have been observed creating webs as wide as ten feet and were first spotted in the United States near homes in Georgia in 2014.
Since then, they had been observed as far west as Oklahoma and as far north as Maryland, but now that