Assessment of pesticide residues in army cutworm moths (Euxoa auxiliaris) from the Greater Yellowstone Ecosystem and their potential consequences to foraging grizzly bears (Ursus arctos horribilis)

During summer, a grizzly bear (Ursus arctos horribilis) in the Greater Yellowstone Ecosystem (GYE) (USA) can excavate and consume millions of army cutworm moths (Euxoa auxiliaris) (ACMs) that aggregate in high elevation talus. Grizzly bears in the GYE were listed as threatened by the US Fish and Wildlife Service in 1975 and were proposed for delisting in 2005. However, questions remain about key bear foods. For example, ACMs are agricultural pests and concern exists about whether they contain pesticides that could be toxic to bears. Consequently, we investigated whether ACMs contain and transport pesticides to bear foraging sites and, if so, whether these levels could be toxic to bears. In 1999 we collected and analyzed ACMs from six bear foraging sites. ACMs were screened for 32 pesticides with gas chromatography with electron capture detection (GC-ECD). Because gas chromatography with tandem mass spectrometry (GC-MS/MS) can be more sensitive than GC-ECD for certain pesticides, we revisited one site in 2001 and analyzed these ACMs with GC-MS/MS. ACMs contained trace or undetectable levels of pesticides in 1999 and 2001, respectively. Based on chemical levels in ACMs and numbers of ACMs a bear can consume, we calculated the potential of chemicals to reach physiological toxicity. These calculations indicate bears do not consume physiologically toxic levels of pesticides and allay concerns they are at risk from pesticides transported by ACMs. If chemical control of ACMs changes in the future, screening new ACM samples taken from bear foraging sites may be warranted.     

The Pending Extinction of the Uncompahgre Fritillary Butterfly

Previous mark-recapture studies and population size estimates indicated that in the 1980s populations of the endangered Uncompahgre fritillary ( Boloria acrocnema ) declined precipitously, apparently leading to extirpation at its type locality. This locality and a nearby second site, both high in the San Juan Mountains of southwestern Colorado, constitute the total known range of B. acrocnema . A survey of 20 presumptive allozyme loci from one B. acrocnema population and seven populations of the closely related B. improba , sampled along the Rocky Mountain cordillera from the Yukon Territory, Canada, to the Wind River Range of Wyoming, revealed that B. acrocnema populations are less variable genetically than are B. improba populations in the northern part of that species' North American range. Genetic variability was also assayed at 18 presumptive allozyme loci in populations of Boloria titania, which were sampled from five of the same locations for comparison with the B. improba-B. acrocnema clade. Low estimates of heterozygosity indicate that genetic and demographic factors preceded by historic human disturbance are causing the decline of B. acrocnema . In addition, persistent drought conditions in southwestern Colorado throughout the 1980s probably contributed to the population declines. Conservation recommendations include strict enforcement of the ban against collecting pursuant to the Endangered Species Act, careful monitoring of known B. acrocnema sites, and possible translocations. Extreme measures beyond these will be costly and may be inappropriate for this relict species, which has an unknown capacity to persist in the face of local weather fluctuations and predicted regional warming trends.