Within‐Body Distributions and Feeding Effects of the Neonicotinoid Insecticide Clothianidin in Bumblebees ( Bombus terrestris )

Low dose of neonicotinoid insecticide reduces foraging motivation of bumblebees

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2018.0506 ◽

2018 ◽

Vol 285 (1883) ◽

pp. 20180506 ◽

Cited By ~ 19

Author(s):

Juho Lämsä ◽

Erno Kuusela ◽

Juha Tuomi ◽

Sini Juntunen ◽

Phillip C. Watts

Keyword(s):

Foraging Behaviour ◽

Low Dose ◽

Bombus Terrestris ◽

Poor Performance ◽

Sugar Solution ◽

Flight Performance ◽

Pollinator Decline ◽

Flower Colours ◽

Neonicotinoid Insecticide ◽

Yellow Orange

Widespread use of neonicotinoid insecticides, such as imidacloprid, is often associated with diminishing populations of bees; this loss of pollinators presents a concern for food security and may cause unpredictable changes in ecological networks. However, little is known about the potential behavioural mechanisms behind the neonicotinoid-associated pollinator decline. We quantified the effects of low-dose (1 ppb) imidacloprid exposure on the foraging behaviour of bumblebees ( Bombus terrestris ). Individual bumblebees were released into a flight arena containing three patches of robotic flowers whose colour (yellow, orange, blue) indicated whether the flower delivered a reward (sugar solution). Exposure to imidacloprid had no significant effect on measures of bumblebee physical performance (such as flight speed) or learning (identifying rewarding flowers). However, pesticide-treated bumblebees had reduced foraging motivation compared with the control bumblebees, as they visited fewer robotic flowers, were slower to start foraging and did not visit all three flower colours as often. Neonicotinoid concentrations of 1 ppb, often reported in plant nectar near agricultural lands, can thus affect the foraging behaviour of bumblebees. Even without a notable impact on flight performance and learning, a reduction in foraging motivation could explain the poor performance of colonies of bumblebees exposed to neonicotinoids.

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General and species-specific impacts of a neonicotinoid insecticide on the ovary development and feeding of wild bumblebee queens

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2017.0123 ◽

2017 ◽

Vol 284 (1854) ◽

pp. 20170123 ◽

Cited By ~ 45

Author(s):

Gemma L. Baron ◽

Nigel E. Raine ◽

Mark J. F. Brown

Keyword(s):

Bombus Terrestris ◽

Average Length ◽

Single Species ◽

Evidence Base ◽

Wild Plants ◽

Ovary Development ◽

Neonicotinoid Insecticide ◽

Multiple Species ◽

Species Specific ◽

Neonicotinoid Pesticides

Bumblebees are essential pollinators of crops and wild plants, but are in decline across the globe. Neonicotinoid pesticides have been implicated as a potential driver of these declines, but most of our evidence base comes from studies of a single species. There is an urgent need to understand whether such results can be generalized across a range of species. Here, we present results of a laboratory experiment testing the impacts of field-relevant doses (1.87–5.32 ppb) of the neonicotinoid thiamethoxam on spring-caught wild queens of four bumblebee species: Bombus terrestris , B. lucorum , B. pratorum and B. pascuorum. Two weeks of exposure to the higher concentration of thiamethoxam caused a reduction in feeding in two out of four species, suggesting species-specific anti-feedant, repellency or toxicity effects. The higher level of thiamethoxam exposure resulted in a reduction in the average length of terminal oocytes in queens of all four species. In addition to providing the first evidence for general effects of neonicotinoids on ovary development in multiple species of wild bumblebee queens, the discovery of species-specific effects on feeding has significant implications for current practices and policy for pesticide risk assessment and use.

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The neonicotinoid insecticide imidacloprid disrupts bumblebee foraging rhythms and sleep

10.1101/2020.04.07.030023 ◽

2020 ◽

Author(s):

Kiah Tasman ◽

Sean A. Rands ◽

James J.L. Hodge

Keyword(s):

Nicotinic Acetylcholine Receptors ◽

Acetylcholine Receptors ◽

Crop Yields ◽

Bombus Terrestris ◽

Floral Resources ◽

Flying Insects ◽

Neonicotinoid Insecticide ◽

Synaptic Neurotransmission ◽

Central Clock ◽

Insect Central Nervous System

SUMMARYNeonicotinoids have been implicated in the large declines observed in flying insects such as bumblebees, an important group of pollinators[1]. Neonicotinoids are agonists of nicotinic acetylcholine receptors that are found throughout the insect central nervous system, and are the main mediators of synaptic neurotransmission[2]. These receptors are important for the function of the insect central clock and circadian rhythms[3, 4]. The clock allows pollinators to coincide their activity with the availability of floral resources, favourable flight temperatures, as well as impacting learning, navigation and communication[5]. Here we show that exposure to the field relevant concentration of 10 µg/L of imidacloprid can cause a reduction in foraging activity and reduce both locomotor and foraging rhythmicity in Bombus terrestris. Foragers showed an increase in daytime sleep and an increase in the proportion of activity occurring at night. This would likely negatively impact foraging and pollination opportunities, reducing the ability of the colony to grow and reproduce, endangering crop yields.

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