title: Thermally moderated firefly activity is delayed by precipitation extremes.
abstract: The timing of events in the life history of temperate insects is most typically primarily cued by one of two drivers: photoperiod or temperature accumulation over the growing season. However, an insect's phenology can also be moderated by other drivers like rainfall or the phenology of its host plants. When multiple drivers of phenology interact, there is greater potential for phenological asynchronies to arise between an organism and those with which it interacts. We examined the phenological patterns of a highly seasonal group of fireflies (Photinusspp., predominantlyP. pyralis) over a 12-year period (2004-2015) across 10 plant communities to determine whether interacting drivers could explain the variability observed in the adult flight activity density (i.e. mating season) of this species. We found that temperature accumulation was the primary driver of phenology, with activity peaks usually occurring at a temperature accumulation of approximately 800 degree days (base 10°C); however, our model found this peak varied by nearly 180 degree-day units among years. This variation could be explained by a quadratic relationship with the accumulation of precipitation in the growing season; in years with either high or low precipitation extremes at our study site, flight activity was delayed. More fireflies were captured in general in herbaceous plant communities with minimal soil disturbance (alfalfa and no-till field crop rotations), but only weak interactions occurred between within-season responses to climatic variables and plant community. The interaction we observed between temperature and precipitation accumulation suggests that, although climate warming has the potential to disrupt phenology of many organisms, changes to regional precipitation patterns can magnify these disruptions.
authors.affiliation: Department of Entomology, Michigan State University, East Lansing, MI 48824, USA; Ecology, Evolutionary Biology and Behavior Program, Michigan State University, East Lansing, MI 48824, USA; Department of Entomology, Pennsylvania State University, State College, PA 16803, USA.
authors.forename: Sara L
authors.initials: SL
authors.lastname: Hermann
authors.affiliation: Biomass Conversion Research Laboratory, Department of Chemical Engineering, Michigan State University, East Lansing, MI 48824, USA; DOE Great Lakes Bioenergy Research Center, East Lansing, MI 48824, USA.
authors.forename: Saisi
authors.initials: S
authors.lastname: Xue
authors.affiliation: Department of Entomology , Michigan State University , East Lansing, MI 48824 , USA.
authors.forename: Logan
authors.initials: L
authors.lastname: Rowe
authors.affiliation: Department of Entomology, Michigan State University, East Lansing, MI 48824, USA; Ecology, Evolutionary Biology and Behavior Program, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Davidson-Lowe
authors.affiliation: Department of Entomology, Michigan State University, East Lansing, MI 48824, USA; Department of Entomology, Pennsylvania State University, State College, PA 16803, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Myers
authors.affiliation: Department of Entomology , Michigan State University , East Lansing, MI 48824 , USA.
authors.forename: Bahodir
authors.initials: B
authors.lastname: Eshchanov
authors.affiliation: Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA; Mozilla Science Laboratory, Mozilla, Mountain View, CA 94041, USA.
authors.forename: Christie A
authors.identifier: 0000-0002-8937-8709
authors.initials: CA
authors.lastname: Bahlai
keywords: Lampyridae; ecoinformatics; lightning bug; long-term ecological research; phenology