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Cave Crickets Monitoring

Hadeonoecus subterraneus. Photo by Rick Olson Hadeonoecus subterraneus. Photo by Rick Olson

Cave Crickets Resource Briefs

Cave Crickets Monitoring Protocol

For more information contact: Kurt Helf

Importance/Issues

  • Cave crickets (Euhadenoecus and Hadenoecus sp.) are commonly found roosting in high densities just inside cave entrances throughout the southeastern United States. They are omnivores that feed on the surface and transfer nutrients in the form of guano, eggs, and bodies into the subsurface habitat.
  • In the Mammoth Cave region cave crickets (Hadenoecus subterraneus) are a keystone species in that their entrance populations subsidize up to three separate cave invertebrate communities through the active, regular transfer of organic matter from the surface to the subsurface. The communities they subsidize can include rare, sometimes endemic, obligate cave-dwelling invertebrates.
  • Natural stressors that affect foraging cave crickets' ability to access primary productivity on the surface, such as contingent climatic conditions (e.g., extremes in maximum temperature and precipitation events across the Southeast predicted by mid-century), can alter the amount of nutrient subsidies they transfer to dependent subsurface communities.
  • Stressors foreign to the cave ecosystem (e.g., cave entrance configuration altered by management actions) can also affect the flow of organic matter subsidies into caves due to their effects on cave cricket foraging behavior and population structure.
  • Given the importance of cave crickets to subsurface ecosystems monitoring of their entrance populations will provide park managers with an early warning of potential trouble with cave ecosystem health and contribute significantly toward managing and protecting their populations.

Preliminary Monitoring Objectives

  1. To determine the status and trend of cave cricket entrance population size, life stage, and sex ratio among 15 developed and undeveloped cave entrances at Mammoth Cave National Park (MACA) during biannual visits.
  2. To determine effects of management decisions (e.g., tour infrastructure improvement) at MACA on cave cricket populations within selected developed caves. Specific monitoring foci will include assessment of the impact of cave entrance modification on cave cricket population size, structure, and localized impacts of infrastructure installation/improvement on cave cricket habitat use.
  3. To determine if a correlation exists between cave temperature, relative humidity and air flow trends, surface temperature, relative humidity and precipitation trends and: a)trends in cave cricket entrance population size, life stage, and sex ratio, and b)trends in spatial distribution within 15 developed and undeveloped cave entrances in MACA using biannual and continuous automated sampling.

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Management Applications

Photograph of cave cricket cluster for analysis. Photo by Kurt Helf. Photograph of cave cricket cluster for analysis. Photo by Kurt Helf.

The intent of the protocol is to ensure that a scientifically credible story about the ecological condition of cave crickets and their responses to contingent climatic conditions, park management actions, land use changes, and other stressors can be told to park visitors and managers alike. These long-term data can contribute to the development of informative models of relationships between cave cricket entrance population dynamics and key environmental factors and management actions by MACA resource managers.

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Last Updated: December 30, 2016 Contact Webmaster