Population profiles of stable flies from eastern Nebraska and the impact of weather variables on their seasonal trends.

摘要

In 2001 and 2002, stable flies, Stomoxys calcitrans (L.), were sampled in Eastern Nebraska using cylindrical Alsynite traps. The objective of this 2-year study was to describe seasonal abundance of these flies in association with observed weather patterns. Sex ratio was consistent with previously reported studies. Trap counts were affected by differences in weather patterns between the two years, and differed among trap locations, with the traps closest to animal facilities capturing the most flies. No difference in age composition between traps was observed, and most captured females were recently emerged, nulliparous flies. Based on these trap catches, a linear model of stable fly activity was developed, using weather variables that significantly affected trap counts. This represented an initial step in developing a system that will permit producers to monitor and predict stable fly activity and subsequent optimize management strategies. Another study conducted in 2002 compared the effectiveness of near-infrared spectroscopy (NIRS) to ovarian development for determination of age of field-collected stable flies. Since the first analyzed chronological age, and the second analyzed physiological age, there was not a direct relationship. My results indicated that NIRS: (1) was not an accurate method of determination of age of field-collected stable flies; (2) required considerable skill in performance and interpretation of the results; and (3) was very time-consuming, requiring more time than physiological age-grading by ovarian development. Moreover, calibrations were not transferable, and the technique involved complex interpretation. In 2004, emergence rates of adult S. calcitrans from puparia maintained at different temperatures and relative humidities levels were investigated. Saturated salt solutions were used to control the humidity levels inside small humidity chambers. A regression equation with best fit for the data was generated. My results demonstrated the importance of not only temperature, but also relative humidity when investigating stable fly developmental time for model development.