DOI: 10.5061/dryad.6djh9w1g5
title: Summer but not spring resource supplementation improves bumblebee colony survival

description: Global agricultural expansion has led to the deterioration of many key
 foraging habitats for bees, but the impacts of nutritional stress caused
 by temporal gaps in food availability can be hard to isolate from other
 agricultural stressors. For bumblebee colonies (Bombus spp.), which have
 an annual lifecycle culminating in a summer reproductive period, this
 issue is further complicated by potential variation in vulnerability over
 the colony lifecycle. Isolating the effects of nutritional stress on
 bumblebee colonies could therefore direct agricultural interventions that
 seek to mitigate against further decline. We assayed whether available
 food resources are limiting colony productivity and survival by
 supplementing post-worker emergence Bombus terrestris colonies with ad
 libitum food during mid-spring or early summer on 20 farms across
 south-east England (“earlier” vs “later” treatments). In mid-spring,
 forage is potentially more abundant, but colonies are at an earlier
 developmental stage, while in early summer, colonies are more established,
 and forage is potentially sparser. Later-supplemented colonies survived
 for significantly longer than both unsupplemented controls and
 earlier-supplemented colonies. We found no detectable effects of
 supplementary feeding on reproductive output, which was minimal overall.
 Colonies in areas dominated by non-flowering arable crops failed soonest
 and had fewer workers irrespective of the feeding regime, and colonies
 experiencing higher weekly precipitation produced fewer workers. Our
 findings suggest that B. terrestris colonies became food-limited towards
 the end of their colony cycle in early summer. We suggest ecological
 intensification through planting native wildflower species may be more
 effective if it targets this flowering period, particularly within heavily
 arable areas, and that a staggered patchwork of mowing or grazing could be
 important in ensuring seasonal resource continuity.
description: # Summer but not spring resource supplementation improves bumblebee colony
 survival Dataset DOI:
 [10.5061/dryad.6djh9w1g5](https://doi.org/10.5061/dryad.6djh9w1g5) ##
 Description of the data and file structure Over the course of April-August
 2024, we placed 60 hand-reared bumblebee colonies on 20 farms around SE
 England, with 3 colonies on each farm. We initiated a staggered feeding
 experiment in order to identify periods of lower pollinator resource
 availability and greater vulnerability. One colony at each site was given
 excess pollen and sugar syrup for 3 weeks from April-May, another for 3
 weeks from May-June (no overlap), with the remaining colony at each site
 acting as a negative control and not receiving any food. Throughout the
 experimental period, we visited each site and colony weekly at night,
 collecting data including but not limited to the number of alive and dead
 workers; queen status (alive/dead/absent); presence of invasive/usurping
 queens; and number of reproductive individuals. The weekly data recorded
 is available in 'Overall weekly data', and the performance of
 each colony (e.g., time survived, peak worker number, sum of reproductive
 individuals produced) is available in 'Overall colony data'.
 'Habitat proportion data by cluster' entails the proportion of
 land-use and habitat category (e.g., non-flowering arable land, land under
 countryside stewardship schemes, impervious surfaces) within a 500m radius
 of each farm site, split into one of four general habitat classifications
 (e.g,. non-flowering arable heavy; pasture mixed) ### Files and variables
 Where appropriate, missing values for all files are NA #### File:
 Habitat_proportion_data_by_cluster.xlsx **Description:** Custom habitat
 and land-use classification; proportion of each within 500m of the farm
 site ##### Variables * Cluster: method to group farms into similar
 land-types * Farm: site identifier, remaining abbreviated for purposes of
 privacy * NFA: proportion of non-flowering arable land within 500m of site
 * FA: proportion of flowering arable land within 500m of site *
 UKA: proportion of unknown arable land within 500m of site *
 TOTPAS: proportion of pasture/grassland within 500m of site *
 FC: proportion of forest cover within 500m of site * HR: proportion of
 hedgerow within 500m of site * CSS: proportion of land under countryside
 stewardship schemes within 500m of site * ORC: proportion of orchard cover
 within 500m of site * IMP: proportion of impervious surface within 500m of
 site * GAR: proportion of garden cover within 500m of site *
 WAT: proportion of water cover within 500m of site #### File:
 Overall_colony_data.xlsx **Description:** Synthesised data for each
 individual colony over the experimental period ##### Variables *
 site: site identifier, remaining abbreviated for purposes of privacy *
 site.num: site number by order of visit * farm_clus: farm cluster by order
 of visit * colony: colony ID by queen rearing number * treatment:
 supplemental feeding treatment * workinit: number of workers at time of
 field placement * workpeak: peak worker count after placement * q.status:
 queen status at point of colony removal * q.status2: binary count of queen
 status at point of colony removal * q.mori: week of experiment in which
 the queen died or was removed * mori.week: week of experiment in which the
 colony was declared moribund and removed * totmal: total number of males
 produced by colony * totgyn: total number of gynes produced by colony *
 totrep: total number of reproductives (males and gynes) produced * repem:
 week of the experiment in which the colony's first reproductive was
 detected * repbin: binary count whether the colony produced a reproductive
 or not  * initprecip: precipitation (mm) in the first week of placement at
 site * meanprecip: mean weekly precipitation (mm) at site * mori.precip:
 precipitation (mm) at each site in the week prior to colony moribundity  *
 c.status: binary count of colony status at the end of the experiment *
 NFAC: proportion of non-flowering arable (conventionally farmed) land
 within 500m of site * NFAR: proportion of non-flowering arable
 (regeneratively farmed) land within 500m of site * NFAO: proportion of
 non-flowering arable (organically farmed) land within 500m of site * NFA:
 proportion of non-flowering arable land within 500m of site *
 FAC: proportion of flowering arable (conventionally farmed) land within
 500m of site * FAR: proportion of flowering arable (regeneratively farmed)
 land within 500m of site * FAO: proportion of flowering arable
 (organically farmed) land within 500m of site * FA: proportion of total
 flowering arable land within 500m of site * UKA: proportion of unknown
 arable land within 500m of site * ORC: proportion of orchard cover within
 500m of site * PC: Proportion of pasture (conventional) cover within a
 500m radius * PR: Proportion of pasture (regenerative) cover within a 500m
 radius * PO: Proportion of pasture (organic) cover within a 500m radius *
 GC: Proportion of grassland (conventional) cover within a 500m radius *
 GR: Proportion of grassland (regenerative) cover within a 500m radius *
 GO: Proportion of grassland (organic) cover within a 500m radius *
 UKP: Proportion of unknown pasture/grassland cover within a 500m radius *
 TOTPAS: proportion of total pasture/grassland within 500m of site * AB1:
 Proportion of Countryside Stewardship Scheme (CSS) AB1 cover within a 500m
 radius * AB8: Proportion of CSS AB8 cover within a 500m radius * AB9:
 Proportion of CSS AB9 cover within a 500m radius * AB11: Proportion of CSS
 AB11 cover within a 500m radius * AB16: Proportion of CSS AB16 cover
 within a 500m radius * HabRes: Proportion of habitat restoration scheme
 cover within a 500m radius * UKM: Proportion of unknown CSS cover within a
 500m radius * CSS: proportion of land under countryside stewardship
 schemes within 500m of site * FC: proportion of forest cover within 500m
 of site * HR: proportion of hedgerow within 500m of site * IMP: proportion
 of impervious surface within 500m of site * GAR: proportion of garden
 cover within 500m of site * WAT: proportion of water cover within 500m of
 site * PC1: value of the first land-use principal component for that site
 * PC2: value of the second land-use principal component for that site *
 pca_clus: 1 of the 4 land-use clusters that the site was placed into
 following Ward's method of cluster analysis #### File:
 Overall_weekly_data.xlsx **Description:** Week-by-week data recorded for
 each colony visit and assessment ##### Variables * week: week of
 experiment * date: date of visit (nightwork often crossed midnight so the
 same date isn't indicative of the same night visit) * site: site
 identifier, remaining abbreviated for purposes of privacy * site.num: site
 number by order of visit * farm_clus: farm cluster by order of visit *
 colony: colony ID by queen rearing number * time: time of visit *
 treatment: supplemental feeding treatment * status: status of the queen at
 the visit  * W1: first worker count * W2: second worker count * W3: third
 worker count * Wmean: mean of the 3 worker counts * Wdead: number of dead
 workers present in colony * usurp: status of usurping *Bombus
 terrestris* queens * para: status of parasitic *Bombus vestalis* queens  *
 wcover: degree of brood wax cover  * egg: number of egg cells * larval:
 number of larval and pupal cells * disL: number of discarded larvae
 present * mal: number of males present * gyn: number of gynes present *
 gynP: number of gyne pupae identified * precip: precipitation (mm) in the
 week prior to visit * removed: binary count of whether the colony was
 declared moribund and removed * NFAC: proportion of non-flowering arable
 (conventionally farmed) land within 500m of site * NFAR: proportion of
 non-flowering arable (regeneratively farmed) land within 500m of site *
 NFAO: proportion of non-flowering arable (organically farmed) land within
 500m of site * NFA: proportion of total non-flowering arable land within
 500m of site * FAC: proportion of flowering arable (conventionally farmed)
 land within 500m of site * FAR: proportion of flowering arable
 (regeneratively farmed) land within 500m of site * FAO: proportion of
 flowering arable (organically farmed) land within 500m of site *
 FA: proportion of total flowering arable land within 500m of site *
 UKA: proportion of unknown arable land within 500m of site *
 ORC: proportion of orchard cover within 500m of site * PC: Proportion of
 pasture (conventional) cover within a 500m radius * PR: Proportion of
 pasture (regenerative) cover within a 500m radius * PO: Proportion of
 pasture (organic) cover within a 500m radius * GC: Proportion of grassland
 (conventional) cover within a 500m radius * GR: Proportion of grassland
 (regenerative) cover within a 500m radius * GO: Proportion of grassland
 (organic) cover within a 500m radius * UKP: Proportion of unknown
 pasture/grassland cover within a 500m radius * TOTPAS: proportion of
 pasture/grassland within 500m of site * AB1: Proportion of Countryside
 Stewardship Scheme (CSS) AB1 cover within a 500m radius * AB8: Proportion
 of CSS AB8 cover within a 500m radius * AB9: Proportion of CSS AB9 cover
 within a 500m radius * AB11: Proportion of CSS AB11 cover within a 500m
 radius * AB16: Proportion of CSS AB16 cover within a 500m radius * HabRes:
 Proportion of habitat restoration scheme cover within a 500m radius * UKM:
 Proportion of unknown CSS cover within a 500m radius * CSS: proportion of
 land under countryside stewardship schemes within 500m of site *
 FC: proportion of forest cover within 500m of site * HR: proportion of
 hedgerow within 500m of site * IMP: proportion of impervious surface
 within 500m of site * GAR: proportion of garden cover within 500m of site
 * WAT: proportion of water cover within 500m of site * PC1: value of the
 first land-use principal component for that site * PC2: value of the
 second land-use principal component for that site * pca_clus: 1 of the 4
 land-use clusters that the site was placed into following Ward's
 method of cluster analysis ## Code/software Made and uploaded in Excel,
 but can also be viewed in Google Sheets  ## Access information Other
 publicly accessible locations of the data: * None Data was derived from
 the following sources: * NA