Effects of Soil and Colony Age on Flea Densities

Science Center Objects

Abundance of fleas is thought to drive rates of plague transmission in the wild. In the complex process of plague maintenance and transmission, fleas as vectors are a potentially weak link in the system that can be exploited. To date, exploiting this link has provided the only stand-alone tools that are operationally effective for managing plague in the black-footed ferret/prairie dog community (i.e., use of various insecticides for flea control).

FORT scientists are addressing the question of how to most efficiently use these tools by conducting studies of flea ecology that examine the influences of colony age, soil characteristics, microclimates in burrows, weather patterns, and differences among flea species.

This research concentrates on fleas that parasitize black-tailed prairie dogs and the conservation implications of flea ecology in prairie dog habitats. Specifically, flea ecology will be compared among colonies with of differing ages and soil characteristics. Prairie dog fleas spend all life stages in close association with soils in prairie dog burrows. As prairie dogs construct a burrow system, soil is manipulated and organic matter, upon which fleas can feed (e.g., feces), accumulates. Also, burrow depth can increase, and the burrow microclimate can become more stable. This suggests temporal changes in the suitability of burrow environments for fleas as prairie dogs construct and modify burrows. Local environmental factors are also of extreme importance to fleas. Two factors, temperature and soil attributes, seem particularly important. Temperature can influence flea egg production and egg laying, and survival and development of fleas. Soil attributes are important because they influence moisture retention and humidity in burrows (another important factor) and abrasive soils can damage the flea exoskeleton. The purpose of this research is to investigate factors that influence the abundance and dispersion of different flea species in prairie dog habitats and in particular at translocation sites with colonies of differing time-since-colonization. Insight into flea dynamics at these sites could provide insight into development of plague risk at translocation sites increasingly used in conservation of prairie dogs and associated species, such as the federally endangered black-footed ferret.

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