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The impacts of light and light types on nocturnal carrion beetles (Silphidae) including ABB. Rachel M. Anschutz William J. Allgeier Daniel G. Snethen W. Wyatt Hoback. American Burying Beetle History. Once distributed over 35 U.S. states and three Canadian provinces.
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The impacts of light and light types on nocturnal carrion beetles (Silphidae) including ABB Rachel M. Anschutz William J. Allgeier Daniel G. Snethen W. Wyatt Hoback
American Burying Beetle History • Once distributed over 35 U.S. states and three Canadian provinces. • During the 20th century its range shrank to less than 10% of this distribution. • The remaining populations are at the peripheries of the former range.
Artificial Light Impacts • Artificial light disturbs nocturnal insects’ essential activities which include: migration, dispersal, foraging, mating, and reproduction. • Light types have different impacts • Usually ultraviolet light is most attractive while sodium vapor is least attractive.
Hypotheses • ABB will be most attracted to light that contains high levels of ultraviolet wave lengths. • Light will impact ABB behavior in responding to carrion resources.
Laboratory Study • 27 ABB were used once. • 19 liter buckets connected with P.V.C. pipe. • 5 types of light used: • Mercury Vapor • Incandescent • Fluorescent • Sodium Vapor • Blacklight • Controlled for intensity
Laboratory Study • Conducted between 20:30 and 05:09. • 300 seconds to acclimate. • 600 seconds to choose. • Given two trials.
Laboratory Results • A chi-square goodness of fit test indicated that • attraction to these light sources is significantly different • (Chi-square=13.18, df=6, c.v.=12.59, p<0.05).
Field Study • Three separate trapping arrays were established > than 1 km apart from each other. 60 meters
Field Study • Mercury vapor, ultraviolet, and halogen • were alternated between array sites. • 24 nights of sampling. • Generators started 30 minutes before sunset and • ran all night. • Traps checked before starting generator and in • the morning prior to 0800.
Field Results • 112 nocturnal beetles were trapped over 24 trap nights. • 32 ABB.
Field Results • These results indicate that ABB foraging • behavior may be disrupted by the presence of lights in the environment.
Field Results • ABB collected most frequently of nocturnally active beetles in lighted traps. • UV was the most attractive. • A trend is evident that indicates ABB to be more affected by light than other species of carrion beetles.
Significance • MV lights have potential to significantly impact ABB. • Possibly explains why ABB has declined compared to other nocturnally active carrion beetle. • Reduction of light and alternative lighting types should be used in areas near the known range of ABB.
Acknowledgements • U.S. Fish and Wildlife Service. • Nebraska Game and Parks Commission.