Overwintering biology and tests of trap and relocate as a conservation measure for burying beetles

Burying beetles utilize dead animal carcasses for feeding and reproductive efforts. They assist with decomposition, reduce the spread of disease, and reduce the number of pest species. The largest species of carrion beetle, the American burying beetle, Nicrophorus americanus is a federally endangered insect with a current distribution of less than 90% of its historic range. Overwintering biology and trap and relocation were studied to determine how Nicrophorus beetles survive northern winters and to assess whether trap and relocation could be used as a conservation measure. Insects are poikilotherms and have evolved strategies to survive temperate winters through changes in behavior and physiology. Overwintering insects either utilize a freeze tolerant or freeze avoidant strategy. Nicrophorus beetles from Nebraska were tested in semi-natural experiment to determine overwintering strategy. There was a strong relationship between beetle depth and soil temperature. Beetles buried at or below the frost line and survived the winter. These data aid in the conservation of re-introduced populations of American burying beetle and by demonstrating that shallow disturbance to soil during winter is unlikely to impact overwintering beetles. Trap-relocation is a technique used to move organisms from an area where human activity and animal habitats overlap. I tested the efficacy of trap-relocation with a surrogate species of burying beetles, N. marginatus and N. carolinus. Baited pitfall traps were used for capture, and comparisons of percent recaptures at different trap sites (control, source, and destination) were used to determine the effects of relocating beetles. The results showed that percent recaptures were slightly lower for relocated N. marginatus ; however, there was no statistical difference among trap sites and recaptures of N. carolinus were higher at relocation sites. Trap-relocation, in circumstances where there is threat to the American burying beetle's habitat, can potentially aid in conserving this species.