No abstract

Opposed to most crayfish species that inhabit permanent bodies of water, a unique burrowing lifestyle has evolved several times throughout the crayfish phylogeny. Burrowing crayfish are considered to be semi-terrestrial, as they burrow to the groundwater—creating complex burrows that occasionally reach 3 m in depth. Because burrowing crayfishes spend most of their lives within their burrow, we lack a basic understanding of the behavior and natural history of these species. However, recent work suggests that burrowing crayfishes may exhibit a higher level of surface activity than previously thought. In the current study, we conducted a behavioral study of the Little Brown Mudbug, Lacunicambarus thomai using video surveillance to determine their degree of surface activity and behavioral patterns. Throughout 664 hrs of footage, we observed a surprisingly high amount of activity at the surface of their burrows—both during the day and night. The percentage of time that individual crayfish was observed at the surface ranged from 21% to 69% per individual, with an average of 42.48% of the time spent at the surface across all crayfish. Additionally, we created an ethogram based on six observed behaviors and found that each behavior had a strong circadian effect. For example, we only observed a single observation of foraging on vegetation during the day, whereas 270 observations of this behavior were documented at night. Overall, our results suggest that burrowing crayfishes may exhibit higher levels of surface activity than previously thought. To increase our understanding of burrowing crayfish behaviors ecology, we encourage the continued use of video-recorded observations in the field and the laboratory.

Crayfish respond rapidly to environmental changes, this responsiveness to environmental changes makes them good detectors for degradation in the environment. Contaminants in the environment may influence crayfish by making them absent in what would be prime habitat. It may also affect the population densities of areas by decreasing the number of individuals in area that superficially look like prime habitat. This study was conducted on Lacunicambarus thomai in a field setting to gather information on the life history of a primary burrowing species of crayfish. Some pre-existing information on the behavior and parts of the life history of Lacunicambarus thomai were incomplete and, in some cases, incorrect. The data showed that what was perceived to be a fully nocturnal species or spends most of its time underground may not necessarily true. Findings of this study conflicted on multiple instances with the previously believed notions. This project provides a better understanding of the life history of a primary burrowing crayfish species: the life history of primary burrowing crayfish has been less than stream dwelling species. This could lead to more studies being conducted on other species to obtain a better understanding of this elusive type of crayfish. The results of this study could be used to get a baseline of the basic life history of these animals as well as other types of burrowing crayfish species.

Primary burrowing crayfish life history and ecology is largely due to their cryptic habitat preferences. Cambarus monongalensis, arguably the most charismatic of all crayfishes, lacks basic life history and habitat data because of the aforementioned obstacles. This study seeks to determine the life history and ecological preferences of populations of C. monongalensis in the northern panhandle of West Virginia and Southwestern Pennsylvania with notes on its natural history. Life history data will include form change and reproductive patterns including juvenile size of departure from the maternal burrow. Habitat data were collected using external burrow morphology and burrow locations within a standardized area collected seasonally to determine the preferences and cyclical patterns of crayfishes. With these data, the conservation of this species, and others that follow a similar life history strategy, is possible

Burrowing crayfish represent a small, specialized group of crayfish that inhabit self-made terrestrial burrows. Primary burrowing crayfish depend upon their burrows for protection, respiration, rearing of young, food storage, and thermoregulation. Burrowing crayfish tend to stay in proximity to or around their burrows causing them to be elusive lifestyle and consequently poorly documented. All crayfish are opportunistic generalists regarding food and have been recorded eating detritus, periphyton, and small invertebrates. Due to their stygobitic lifestyle, food resources are also limited to what is near their burrow, which commonly includes vegetation as well as smaller invertebrates. The predatory behaviors of burrowing crayfish has been studied and observed in abundance in epigean crayfish, however, it has been rare and few studies have been conducted on this behavior in burrowing species. This study utilized 24-h surveillance of a burrowing crayfish species, the Little Brown Mud Bug (Lacunicambarus thomai). A total of 633 H of videos were recorded of 6 different crayfish at varying times for each individual. Predatory behaviors were observed on several organisms including ants, worms, spiders, and dragonfly naiads. Gut analysis was performed on 23 L. thomai from 4 separate populations confirming the findings of the video footage that, in all populations, both animal and vegetation were being consumed. This study suggested that a sit-and-wait predation behavior may be a far more common foraging behavior in burrowing crayfish than previously observed.