When we recently drove to New Mexico, we discovered tarantula hordes sharing southeast Colorado highways with us. I’d seen posts regarding a Tarantula Fest in La Junta and wondered if they’d attended. Once we counted more than a dozen palm-size, hairy brown creatures crossing a stretch of asphalt slicing through section after section of native grassland I needed to discover these eight-legged guys’ intended destination. I didn’t want to join them.
Come to find out, guys they are. This annual tarantula march is not a migration technically. It involves local males of the species seeking mates isolated into webbed-encased burrows throughout undisturbed grasslands covering arid eastern Colorado and western Kansas. Scores of these shy creatures occupy this landscape unseen most of the year. That is until mating season kicks in. Likely dates to spy this trek for love start in late August as temps drop and last through October when I presume freezing nights put the kibosh on natural urges.
Fellas of the brown tarantula species mature sexually between five to ten years of age—yeah, these are long-lived arachnids. Gals mature later, living up to three decades and producing up to 4,000 offspring during their reproductive years. Once these arachnids reach goal age, Mother Nature flicks the on switch, sending males on their odyssey to search for breeding partners. Using touch, pheromones, and vibrations to find mates, these huge spiders may hike over a mile to contribute to the gene pool.
Once Mr. Tarantula finds a desirable female’s homey burrow on the lonesome prairie, he uses his pedipalps, aka arm/hand-like extensions located near his jaws, to drum on the object of his desire’s so-to-speak door. According to some sources, this rhythm lures an intrigued damsel from underground so the two can complete necessary mating rituals. If the guy is lucky, he survives this relationship and scurries off as fast as a tarantula can to find another interested partner. Apparently, once fertilization takes place, some females decide their partners qualify as tasty meals.
Surviving males wander from burrow to burrow, seeking reproductive opportunity. Once those honeymoons end, males cross the equivalent of the Rainbow Bridge—however that’s phrased in arachnid-speak.
Fertilized females create a giant (envision a golf ball) egg sac, where she deposits the next generation and protects her treasure from predators while rotating it like a rotisserie turns roasting chicken. Soon, hatchlings by the hundreds emerge and begin the process again, establishing their own burrows and controlling prairie pests. As scary as tarantulas look, they are good guys. They eat undesirable insects.
Speaking of insects, one of a tarantula’s most feared predators is the huge tarantula hawk, a spider-hunting wasp. They’re the United States’ largest wasp and feed on nectar. Unfortunately, successful reproduction requires a sacrificial tarantula. In this real-life horror story, fertile female wasps inject venom into target tarantulas, paralyzing them before dragging them into burrows. Once spiders are in place, female wasps lay eggs on them. Within days, larvae hatch and begin feasting on unmoving but still-living, hosts.
Based on the number of tarantulas we encountered crossing the highway, few suffer this fate. Most live long spidey-lives, continuing annual reproductive efforts and contributing to healthy prairies. To learn more and have fun, investigate La Junta’s Tarantula Fest.
Karen Madorin is a retired teacher, writer, photographer, outdoors lover, and sixth-generation Kansan.