Novel approaches to examining the effects of systemic pesticides in honey bee colonies

Madison King Author

08/04/2020 Added

34 Plays

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A study implementing unique approaches of evaluating pesticide exposure in honey bees through possible wax gland excretions.

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[00:00:01.362]Hello. My name is Madison King
[00:00:03.638]and I'm a junior in microbiology.
[00:00:06.549]This summer, I've investigated
[00:00:08.444]novel approaches to examining
[00:00:10.645]the effects of systemic pesticides,
[00:00:13.031]including nicotine-like insecticides
[00:00:15.341]or neonicotinoids,
[00:00:17.021]in honey bee colonies
[00:00:18.879]with the help of Dr. Judy Wu-Smart
[00:00:21.167]and the University of Nebraska-
[00:00:22.788]Lincoln UCARE program.
[00:00:26.802]Pesticides picked up by foraging bees
[00:00:29.722]from the environment are present
[00:00:31.838]in beeswax or comb
[00:00:33.784]as well as the nectar
[00:00:34.974]and pollen stored in combs,
[00:00:37.198]but it is unclear precisely
[00:00:38.828]how they arrive there.
[00:00:41.182]From previous studies,
[00:00:42.482]we suspect bees are excreting
[00:00:44.347]pesticide residues from their body
[00:00:46.265]as an alternative to the
[00:00:47.938]energetically costly process
[00:00:49.792]of detoxification.
[00:00:52.245]Through this study,
[00:00:53.495]we hope to examine
[00:00:54.740]the role honey bee wax glands
[00:00:56.533]play when bees are exposed
[00:00:58.289]to the neonicotinoid insecticide,
[00:01:00.382]imidacloprid, during different stages
[00:01:02.865]of adult development.
[00:01:06.187]Honey bee workers express
[00:01:07.937]division of labor based on
[00:01:09.163]age and transition tasks from
[00:01:12.022]nurse bee to house bee to forager bee
[00:01:14.853]throughout their lives.
[00:01:17.114]Examining how honey bees
[00:01:18.874]in different life stages
[00:01:20.223]metabolize and/or excrete toxins
[00:01:23.294]from pesticide-laden nectar
[00:01:24.838]is critical for developing better
[00:01:27.094]management options for beekeepers
[00:01:29.359]to mitigate the impacts of
[00:01:31.432]pesticide exposure on bees.
[00:01:34.716]So, are bees utilizing wax production
[00:01:37.646]as a novel route of dissipation
[00:01:39.629]for pesticide residues in
[00:01:41.450]contaminated nectar?
[00:01:43.584]To answer that question,
[00:01:45.004]I had 3 research objectives;
[00:01:48.037]First, to determine
[00:01:49.510]at what age are bees
[00:01:50.869]visiting and consuming
[00:01:52.433]syrup treatments fed in
[00:01:53.797]experimental hives;
[00:01:56.501]Second, to examine the use of
[00:01:58.521]dye markers in pesticide-laden syrup
[00:02:00.811]fed to honey bee colonies
[00:02:02.690]to measure excretion rates
[00:02:04.166]through wax production;
[00:02:06.438]and lastly, to determine the effects
[00:02:08.318]of systemic neonicotinoid insecticides
[00:02:10.983]on wax production
[00:02:12.530]and impact at a colony-level.
[00:02:16.194]The first portion of my research
[00:02:18.044]was spent marking newly emerged
[00:02:19.886]bees with paint
[00:02:21.269]to later identify the age cohort
[00:02:23.518]of the bees being observed
[00:02:25.088]within the hive.
[00:02:26.719]Fortunately, newly emerged bees
[00:02:29.119]are unable to fly
[00:02:30.268]and have potentiated venom,
[00:02:31.935]removing the need for a veil
[00:02:34.058]or protective equipment.
[00:02:36.421]Over the course of my research,
[00:02:38.151]9 cohort colors were
[00:02:40.025]repeatedly cycled to best
[00:02:41.602]represent the temporal
[00:02:42.660]change in hive responsibilities.
[00:02:45.707]it is known that honey bees
[00:02:47.107]start their life cycle
[00:02:48.177]caring for young as nurse bees
[00:02:49.856]and maintaining the hive
[00:02:51.018]and progressively move to
[00:02:52.882]more dangerous jobs
[00:02:53.842]like guarding the hive entrance
[00:02:55.544]and foraging for resources.
[00:02:59.972]The next part of my research
[00:03:01.547]involved creating a pesticide solution.
[00:03:03.772]To do this, imidacloprid was
[00:03:06.122]dissolved in acetone,
[00:03:07.440]then serially diluted to a
[00:03:09.528]100 ppb sugar solution.
[00:03:12.753]Syrup treatments were dyed
[00:03:14.093]with equal concentrations of
[00:03:15.634]food coloring created for
[00:03:17.475]2 pesticide contaminated
[00:03:19.856]treatment colonies,
[00:03:21.210]red and blue respectively,
[00:03:22.712]and 1 acetone contaminated
[00:03:24.585]control colony, purple.
[00:03:27.692]Roughly 200 ml of syrup treatment
[00:03:29.672]was administered every
[00:03:31.142]3 days through a feeder
[00:03:32.310]to each observation hive
[00:03:33.903]over 2 weeks.
[00:03:37.577]To answer my first objective,
[00:03:39.527]15-minute behavioral observations
[00:03:42.446]were recorded twice daily
[00:03:44.278]over the course of treatment
[00:03:46.079]to identify the changes
[00:03:47.355]in labor tasks
[00:03:48.610]in relation to their age and treatments
[00:03:51.257]to assess potential
[00:03:52.498]colony-level impacts
[00:03:54.023]after sub-lethal imidacloprid exposure.
[00:03:58.821]In order to assess wax production,
[00:04:01.011]3 small micro colonies
[00:04:03.132]were created consisting of
[00:04:05.201]roughly 5,000 worker bees
[00:04:06.940]and a laying queen
[00:04:08.502]and ample open space
[00:04:09.933]to promote comb building
[00:04:11.316]and encourage wax production.
[00:04:13.828]The extra wax produced
[00:04:15.538]was then removed,
[00:04:16.813]melted to remove debris,
[00:04:18.945]weighed, and compared
[00:04:20.406]across treatments.
[00:04:22.679]Lastly, transparencies were
[00:04:24.409]added to the bottom of
[00:04:25.737]each observation hive
[00:04:27.415]to collect fallen wax scales
[00:04:29.381]exuded from the wax glands
[00:04:30.850]located on the underside
[00:04:32.878]of the honey bee abdomen.
[00:04:35.205]Roughly 20 wax scales
[00:04:36.725]were randomly sampled
[00:04:38.066]from each colony
[00:04:39.093]and measured under a
[00:04:40.337]microscope to compare
[00:04:41.547]length, width, and thickness.
[00:04:47.008]Through behavioral observations,
[00:04:49.078]we determined the majority
[00:04:50.803]of feeder usage
[00:04:52.072]comes from forager and guard bees
[00:04:54.085]about 17 days or older.
[00:04:56.268]However, younger bees
[00:04:58.008]were also found
[00:04:58.986]to utilize the feeder.
[00:05:02.340]Neonicotinoids are known
[00:05:04.530]to affect foraging behavior,
[00:05:06.493]resulting in younger bees
[00:05:08.343]foraging sooner than normal.
[00:05:11.156]This would explain
[00:05:12.116]the smaller proportion of
[00:05:13.127]young bees foraging and
[00:05:14.807]using the feeder in
[00:05:15.651]the treatment colonies.
[00:05:19.336]After microscopic investigation,
[00:05:21.256]no visible concentration
[00:05:23.110]of dye was found
[00:05:24.100]in any wax scales.
[00:05:25.899]Comparing average length,
[00:05:27.412]width, and thickness of wax scales
[00:05:29.953]produced after 1 week
[00:05:31.464]of treatment yielded
[00:05:32.816]no statistical differences
[00:05:34.307]between colonies.
[00:05:35.654]However, treatment is still
[00:05:37.389]being provided to these hives
[00:05:38.789]and wax scale data
[00:05:40.409]will continue to be collected
[00:05:41.731]until Fall.
[00:05:42.780]It is possible that
[00:05:44.451]the differences in wax scales
[00:05:45.921]may become more obvious
[00:05:47.771]as the colony becomes
[00:05:49.537]exposed to treatments
[00:05:50.848]for a longer period.
[00:05:53.859]Despite no differences
[00:05:55.309]found in wax scale size
[00:05:57.194]among treatment groups,
[00:05:58.657]pesticide treated colonies
[00:06:00.694]produced significantly less comb
[00:06:02.958]than the control colony
[00:06:04.646]suggesting imidacloprid affects
[00:06:06.760]wax production in honey bees
[00:06:08.681]through other means.
[00:06:11.999]This research found
[00:06:13.409]that foragers and guard bees
[00:06:15.273]utilized supplemental syrup feeders
[00:06:17.551]to disperse treatments
[00:06:18.803]within the hive.
[00:06:20.653]Imidacloprid treated colonies
[00:06:22.183]displayed precocious foraging
[00:06:23.638]behavior resulting in
[00:06:25.567]younger bees using the
[00:06:26.664]syrup feeder.
[00:06:28.554]And while the wax scales
[00:06:29.814]failed to prove
[00:06:30.778]physiological changes,
[00:06:32.190]we know imidacloprid treatments
[00:06:34.499]inhibited effective wax production
[00:06:36.743]in experimental colonies.
[00:06:38.395]These findings open up
[00:06:40.233]avenues for further study
[00:06:41.845]to further understand
[00:06:43.145]the processes that
[00:06:44.128]lead to this.
[00:06:45.330]Thank you.

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Novel approaches to examining the effects of systemic pesticides in honey bee colonies

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