Death from below: Sit-and-wait predatory behavior in a burrowing crayfish (Lacunicambarus thomai)

Abstract

The biology of burrowing crayfishes remains elusive to biologists, primarily because these animals spend a majority of their lives within the confines of their burrow. Scattered observations of burrowing crayfishes have suggested that burrowing crayfish may exhibit a greater degree of surface activity than previously thought. Surface behavior may be related to social interactions, predator defense, or prey capture. But documentation of these behaviors is rare, and few studies have been conducted on the predatory behaviors of burrowing crayfishes. Here, we report the findings of 24-h video recording surveys conducted on a burrowing crayfish species, the Little Brown Mudbug (Lacunicambarus thomai). In total, we recorded and watched 633 h of video. We observed L. thomai sitting atop their burrow engaging in sit-and-wait predatory behavior. This ambush predatory behavior was used on several different animal prey items, including spiders (Lycosidae), slugs (Philomycidae), and dragonfly nymphs (Aeshnidae). We also we recorded crayfish cutting terrestrial vegetation near their burrow entrance and pulling it down into their burrow. Additionally, we analyzed the gut contents of 23 L. thomai from 4 populations to understand the generality of our foraging observations. Indeed, gut content analyses confirmed that all populations consumed both animal prey and vegetation. Overall, our recordings demonstrate that sit-and-wait predatory behavior may be a common foraging behavior among burrowing crayfishes. Further, our observations highlight the trophic role of burrowing crayfish species and emphasizes how these animals forage on both animal and plant communities in terrestrial habitats.