Scolopendra heros arizonensis
Size: Up to 20 cm
Group Guild Status
Trogloxene Predator Rare
Centipedes in the genus Scolopendra are predators of a wide variety of invertebrates and the larger species manage to capture small vertebrates including amphibians, lizards, snakes, and small rodents and birds (Elzinga 1994; McCormick and Polis 1982; Molinari et al. 2005; Schal et al. 1984). Conversely, Scolopendra centipedes are prey for some snake species, including several small rattlesnake species (Holycross et al. 2002; Taylor 2001). The largest known centipede species (S. gigantea) was recorded capturing and feeding on three species of bats in a single cave in Venezuela (Molinari et al. 2005). Scolopendrids envenomate their prey with a neurotoxin injected using their hollow forcipules, which are the modified first legs of the animals. Their bite is reported to be very painful, but is not considered particularly dangerous to adult humans.
A single adult of this large, colorful desert centipede was observed in the bottom of the Jackrabbit Shaft during a post-study trip to the cave on May 31, 2012 (Photo 1). This powerful predator likely finds ample food in the Jackrabbit shaft with some of its prey potentially including the Western Banded Gecko (Coleonyx variegatus), the endemic scorpion (Pseudouroctonus nr. apacheanus), the introduced cockroach (Periplaneta australasiae), the centipede (Dendrothereua sp.), the field cricket (Gryllus multipulsator), and a variety of medium-sized spiders. The dorso-ventrally flattened morphology of centipedes facilitates their accessing narrow crevices in bedrock and other habitats, where they find many of their arthropod prey.
The ecological discussion in the paper that recorded predation on bats by S. gigantea in Venezuela (Molinari et al. 2005) suggested three potential strategies that these centipedes may use to capture bats; actively searching the ceiling of the cave for roosting bats; sit and wait predation, where the centipedes position themselves in bat roost areas and wait for a bat to alight close enough to be captured; or, hanging from the ceiling of the roost by several pairs of hind legs and capturing the bats in flight when they circulate in the roost area. The latter behavior has been documented in the tropics where snakes capture bats in flight while hanging from vegetation in cave entrances. While this strategy may intuitively seem improbable behavior for a centipede, observations of S. heros show that they commonly raise the upper half (or more) of their body to reach for surfaces (and hunt for prey?) as they forage in caves (RBP, personal observation). All three of the bat species predated by S. gigantea are considerably larger than the Cave Myotis, but adult S. gigantea are commonly 30 cm in length, and apparently quite capable of capturing these larger bats. While S. heros, the centipede species present in Kartchner Caverns, is considerably smaller, attaining 20 centimeters in length, they should physically be quite capable of capturing small bats such as Myotis spp. While we suspect the potential that S. heros ever preys on M. velifer in the cave is very low, the possibility that this may occur on rare occasions cannot be precluded. The most likely location in the cave where such an interaction between these species might occur would be in the breakdown area of the Entrance Sink, where the bats regularly enter and exit the cave to forage, and where the access area is small enough to make capture by a large centipede potentially feasible. We believe there is no potential for the centipedes foraging for bats in the main bat roosts in the Big Room of the cave since they are unlikely to occur in the deeper reaches of the cave.
Scolopendrids are not uncommon in cave entrances, and these areas are a natural element of their habitat in karst environments. We consider most occurrences of scolopendrid (and other) centipedes in caves as trogloxenes.
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