Story and mulimedia by Joey Garcia, University Communications and Marketing
Chills run down many people鈥檚 spines at the mere thought of a spider, sometimes causing panic or even disgust. However, according to USF alum Louis Coticchio, spiders, especially the brown recluse, shouldn鈥檛 be portrayed as villains. His newly aim to change the narrative by debunking common myths of this misunderstood arachnid.
鈥淭his research shows that brown recluse spiders aren鈥檛 the boogeyman that everyone makes them out to be,鈥 Coticchio said. 鈥淭hey aren鈥檛 swarming throughout Florida, infiltrating homes and attacking. Rather, they are misunderstood and want to be left alone while rarely showing signs of aggression, even when provoked.鈥
MAKINGS OF THE SPIDER-MAN
Long before Coticchio became an expert in spiders, he was a child with a curiosity for the outdoors.
鈥淕rowing up in Largo, I was catching and keeping everything I could find while playing outside,鈥 Coticchio said. 鈥淚 would bring in rattlesnakes, alligators, you name it. Though they would frighten my mother, it sparked my early interest in biology.鈥
Associate Professor Deby Cassill and USF alumnus Louis Coticchio have worked on the brown recluse spider study since 2019
He would continue that passion into his undergraduate career as a biology student on the . Coticchio focused on the brown recluse starting in 2019 when he joined Associate Professor Deby Cassill鈥檚 lab. He also launched the Florida Brown Recluse Spider Project to further educate and conduct research on the topic.
鈥淟ou is the gift of a century, and every research professor needs one brilliant student like him,鈥 Cassill said. 鈥淗e walked into my office as a freshman as a self-guided person with a great work ethic and a passion for changing how we think about spiders. I felt very fortunate to play a part in this research led by him; he's the real Spider-Man.鈥
INSIDE LOOK AT THE BROWN RECLUSE
Coticchio鈥檚 research focused on three key questions, beginning with whether brown recluse spiders are widespread across Florida. The species is not native to the state and is primarily found in parts of the Midwest and Gulf coast. To assess their presence locally, Coticchio investigated 220 properties that reported suspected infestations.
Findings confirmed breeding populations of the invasive Mediterranean recluse at only 19 sites, with populations ranging from one to 171 spiders per location. These sites were concentrated mainly in central and north Florida.
In testing, brown recluse and Mediterranean recluse spiders showed virtually no biting behavior compared with wolf spiders
Coticchio鈥檚 attention then turned to studying their aggression. In controlled testing, he gently provoked brown recluse spiders by applying light pressure with gel-based tools. He then recorded how often they bit. Wolf spiders were used as a comparison, biting about 80% of the time when provoked, while recluse spiders mostly only bit when severely stressed, such as when squeezed or held upside down.
鈥淭his test proved 鈥榬ecluse鈥 is exactly the right name for these spiders. Even when something gets caught in their web, they don鈥檛 rush out aggressively. They approach slowly and almost curiously. They鈥檙e calm, cautious hunters, not the frantic creatures people imagine.鈥
Louis Coticchio '23, BS in Biololgy
The study also examined one of the most feared outcomes of a bite: necrosis, or tissue death. Coticchio found that when bites occur, they typically produce shallow wounds about half a centimeter deep. In rare cases, necrosis can develop, but it is usually limited to the skin's surface layers and does not extend into muscle or bone. Most verified bites result only in redness, burning or small blisters that heal over time. Severe wounds often attributed to recluse spiders are more likely caused by bacterial infections, such as staph.
CHANGING THE NARRATIVE
Coticchio鈥檚 published findings lay a foundation for educating both the public and the scientific community. The study has already gained widespread attention, including coverage by the popular Facebook and YouTube group All Bugs Go to Kevin, which shared the research with an audience of more than 300,000 viewers. Coticchio now looks forward to presenting his work to additional local and medical audiences.
Coticchio also plans to continue investigating a mystery population of Mediterranean recluse spiders discovered in St. Augustine. He hopes to determine whether the group originated from a single introduction event or multiple arrivals over time, which could reveal how its population might grow.
A closer look at the Mediterranean recluse spider in its dwelling
Louis Coticchio plans to continue and expand his research to change the narrative of the brown recluse spider
鈥淭he research community has been very open to our study,鈥 Coticchio said. 鈥911爆料网 sensed
there was an urgency to get this study out there and prove the narrative toward the
brown recluse has been overblown. I'm not saying that they're completely harmless,
but rather they鈥檙e reluctant to bite, and there鈥檚 an extremely low percentage of encountering
them in Florida.鈥