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Dryad

Data from: The heat is on: reduced detection of floral scents after heat waves in bumblebees

Cite this dataset

Nooten, Sabine Sylvia; Korten, Hanno; Kárpáti, Zsolt; Schmitt, Thomas (2024). Data from: The heat is on: reduced detection of floral scents after heat waves in bumblebees [Dataset]. Dryad. https://doi.org/10.5061/dryad.jsxksn0hh

Abstract

Global climate change disrupts key ecological processes and biotic interactions. The recent increase in heat wave frequency and severity prompts the evaluation of physiological processes that ensure the maintenance of vital ecosystem services such as pollination. We use experimental heat waves to determine how high temperatures affect the bumblebees’ ability to detect floral scents. Heat waves induced strong reductions in antennal responses to floral scents in both tested bumblebee species (Bombus terrestris and Bombus pascuorum). These reductions were generally stronger in workers than in males. Bumblebees showed no consistent pattern of recovery 24 hours after heat events. Our results suggest that the projected increased frequency and severity of heat waves may jeopardize bumblebee-mediated pollination services by disrupting the chemical communication between plants and pollinators. The reduced chemosensitivity can decrease the bumblebees’ abilities to locate food sources and lead to declines in colonies and populations.

README: The heat is on: reduced detection of floral scents after heat waves in bumblebees

https://doi.org/10.5061/dryad.jsxksn0hh

The dataset contains electroantennography (EAG) recordings of bumblebees to flower volatile stimuli. \
Experimentally, we assessed the effects of simulated heat waves on bumblebees' ability to detect flower volatiles. To this end, we compared EAG recordings of male and worker, from 2 bumblebee species, in 5 treatment conditions, to 3 flower volatiles, at 3 concentrations. 2 sets of comparisons were done: \
Comparison 1: we assessed whether workers and males detect floral scents equally by comparing EAG recordings of bumblebees from control groups (that did not undergo any experimental heat wave treatment)\
Comparison 2: we analysed the effects of simulated heat waves on antennal responses of bumblebee workers by comparing EAG recordings of bumblebees that underwent an experimental heat wave treatment (4 conditions: heat, heat + access to liquid, heat + 24h resting period before testing, heat + dry humidity conditions) and the control group. For males bumblebees we compared control group vs heat + dry humidity conditions. \
3 concentrations of 3 flower volatiles were tested for both comparisons

1). We found that antennal response to flower volatiles were dose-dependent (= stronger with higher concentrations), and these responses were somewhat stronger in workers than in males\
2.) We found that experimental heat waves reduced bumblebees responses to flower volatiles for both species and both sexes in almost all instances significantly. Reductions of antennal responses were stronger in workers than in males.

Description of the data and file structure

Meta for Data_bumblebee_sense_of_smell.csv
Column Description
A unique sample identifier
B Nest ID
C Bumblebee species  (B. pascuorum or B. terrestris)
D Sex  (male or worker bumblebee)
E Treatment - 5 heat shock treatments:
Cont Control
HS1 40ºC for 2.75 h / 90% relative humidity
HS2_liq 40ºC for 2.75 h / 90% relative humidity, access to API-invert during treatment
HS3_rec 40ºC for 2.75 h / 90% relative humidity, humidity and 24 h resting time before electro antenno grams
HS4_dry 40ºC for 2.75 h / 15% relative humidity, 
F TreatmentNew - for plots (treatments with males got an additional 'm')
Cont Control (worker)
mCont Control (males)
HS1 40ºC for 2.75 h / 90% relative humidity (worker)
HS2_liq 40ºC for 2.75 h / 90% relative humidity, access to API-invert during treatment (worker)
HS3_rec 40ºC for 2.75 h / 90% relative humidity, humidity and 24 h resting time before electro antenno grams (worker)
HS4_dry 40ºC for 2.75 h / 15% relative humidity (worker)
mHS4_dry 40ºC for 2.75 h / 15% relative humidity (males)
G Concentration ( concentration of floral scents: either 1ug, 10ug or 100ug)
H Geraniol (electro antennal response of bumblebee to Geraniol stimulus, in mV, response variable)
I Ocimen (electro antennal response of bumblebee to Ocimene stimulus, in mV, response variable)
J Nonanal (electro antennal response of bumblebee to Nonanal stimulus, in mV, response variable)

Sharing/Access information

The data are stored at figshare for review purposes (link: https://figshare.com/s/bcef6705c1672bf83128)

Code/Software

The statistical analyses were cnducted in R Studio (R version 4.2.0 (2022-04-22) -- "Vigorous Calisthenics" Copyright (C) 2022 The R Foundation for Statistical Computing Platform. The folwoing packages were used: library(MASS), library(car), library(emmeans), for the plots library(ggplot2)

Methods

The collected data are electroantennography (EAG) recordings. The antennal signal to stimulus was 10 times pre-amplified, converted to a digital signal using a DC amplifier interface (IDAC-2, Syntech) and recorded with GC-EAD software (GC-EAD 2014, version 1.2.5, Syntech). See method section of the manuscript 'Physiological experiments – electroantennography' for more detailed description.

The statistical analyses were conducted in R Studio (R version 4.3.2 (2023-10-31) -- "Eye Holes" Copyright (C) 2023 The R Foundation for Statistical Computing Platform. 
The following packages were used: library(MASS), library(car), library(emmeans),library (glmmTMB), for the plots library(ggplot2) for the plots library(ggplot2).

Funding

Deutsche Forschungsgemeinschaft, Award: 445715161