DOI: 10.5061/dryad.43f8k
title: Data from: Flight of the bumble bee: buzzes predict pollination services

description: Multiple interacting factors drive recent declines in wild and managed
 bees, threatening their pollination services. Widespread and intensive
 monitoring could lead to more effective management of wild and managed
 bees. However, tracking their dynamic populations is costly. We tested the
 effectiveness of an inexpensive, noninvasive and passive acoustic survey
 technique for monitoring bumble bee behavior and pollination services.
 First, we assessed the relationship between the first harmonic of the
 flight buzz (characteristic frequency) and pollinator functional traits
 that influence pollination success using flight cage experiments and a
 literature search. We analyzed passive acoustic survey data from three
 locations on Pennsylvania Mountain, Colorado to estimate bumble bee
 activity. We developed an algorithm based on Computational Auditory Scene
 Analysis that identified and quantified the number of buzzes recorded in
 each location. We then compared visual and acoustic estimates of bumble
 bee activity. Using pollinator exclusion experiments, we tested the power
 of buzz density to predict pollination services at the landscape scale for
 two bumble bee pollinated alpine forbs (Trifolium dasyphyllum and T.
 parryi). We found that the characteristic frequency was correlated with
 traits known to affect pollination efficacy, explaining 30-52% of
 variation in body size and tongue length. Buzz density was highly
 correlated with visual estimates of bumble bee density (r = 0.97),
 indicating that acoustic signals are predictive of bumble bee activity.
 Buzz density predicted seed set in two alpine forbs when bumble bees were
 permitted access to the flowers, but not when they were excluded from
 visiting. Our results indicate that acoustic signatures of flight can be
 deciphered to monitor bee activity and pollination services to bumble bee
 pollinated plants. We propose that applications of this technique could
 assist scientists and farmers in rapidly detecting and responding to bee
 population declines.
description: Bumble bee morphology
 and flight buzz frequency - alpine speciesMorphological
 measurements (tongue length, wing length, intertegular distance) and
 flight buzz frequency for two alpine bumble bee species (Bombus balteatus
 and B. sylvicola) as collected by Nicole Miller-Struttmann and colleagues
 in 2014 at Niwot Ridge Long Term Ecological Research Site in Colorado.
 COLUMN DETAILS: BeeNumber - a unique identifier given to each individual
 collected Species - bumble bee species Caste - bumble bee caste BuzzNumber
 - the buzz replicate (1 through 3) for each individual FlightBuzzFrequency
 - the characteristic frequency of the buzz in mm TongueLength - tongue
 length in mm WingLength - wing length in mm IntertegularDistance - the
 distance between the bases of the wings in mmBumble bee morphology
 and flight buzz frequency - literature surveyTongue length (mm) and
 flight buzz frequency (Hz) for queens and workers of 17 bumble bee species
 as reported in the literature.Automated versus manual
 bumble bee flight buzz countsBuzz counts quantified
 by manual (auditory and visual) counts and automated counts produced by
 the algorithm (modified Computational Auditory Scene Analysis with focal
 templates) composed by David Heise with data collected in 2015 at
 Pennsylvania Mountain in Colorado.Bee density, buzz
 density, and pollination servicesBumble bee density,
 flight buzz density (Hz) and pollination services (seed set) as collected
 by Galen and colleagues in 2015 at Pennsylvania Mountain in Colorado.
 COLUMN DETAILS: Site - the location on Pennsylvania Mountain PlantSpecies
 - the genus and species name of the focal plant BuzzesPerHour - the number
 of buzzes recorded per hour via acoustic monitoring BeesPerHour - the
 number of bees recorded per hour via visual surveys ControlSeedSet - seed
 set of individuals left open to pollinators ExcludedSeedSet - seed set of
 individuals covered in mesh netting to exclude bumble bee
 pollinators.