Modulation of Direction Selective Motion Detecting Neurons by Appetitive Odors in the Hoverfly Pollinator Eristalis tenax and the Effects of Acute Contact Exposure to Imidacloprid
(2023) BMEM01 20231Department of Biomedical Engineering
- Abstract
- Over recent decades, use of insecticides to protect plants from pests and harmful insects have increased manyfold.
Neonicotinoid insecticides, such as Imidacloprid (IMI) acts as partial agonists on nicotinic acetylcholine receptors which are widely present in both the central and peripheral nervous system of insects.
Pollinators like Eristalis tenax are frequently exposed to these pesticides but have been shown to also have a high tolerance to IMI, requiring high doses for it to be lethal.
Acute or chronic exposure to sub-lethal doses of IMI still presents a serious threat to the these flies as it may cause paralysis or other impairments such as impaired vision.
E.tenax relies on visual as well as olfactory cues to aid them in foraging... (More) - Over recent decades, use of insecticides to protect plants from pests and harmful insects have increased manyfold.
Neonicotinoid insecticides, such as Imidacloprid (IMI) acts as partial agonists on nicotinic acetylcholine receptors which are widely present in both the central and peripheral nervous system of insects.
Pollinators like Eristalis tenax are frequently exposed to these pesticides but have been shown to also have a high tolerance to IMI, requiring high doses for it to be lethal.
Acute or chronic exposure to sub-lethal doses of IMI still presents a serious threat to the these flies as it may cause paralysis or other impairments such as impaired vision.
E.tenax relies on visual as well as olfactory cues to aid them in foraging and navigation and thus they may become unable to perform vital tasks or be exposed to predators.
In addition to vision, odor cues have long been known to be important for the proliferation of all kinds of animals. Studies on mosquitoes, fruit flies and blowflies suggests that stimulation to the olfactory system directly effects and modulates the visual system and is believed to do so through octopaminergic neurons.
This project's aim was to study the connection between sight and smell in the hoverfly pollinator E.tenax and to provide a basis for future research into this matter.
To achieve this we developed routines and systems for the testing of olfactory and visual stimulus simultaneously, on and off the influence of imidacloprid. We conducted in vivo extracellular recordings from Lobula Plate Tangential Cell (LPTC) type neurons in the third optic ganglion of E.tenax and observed the response to odor cues, visual cues and their interactive effects. We then exposed them to IMI through acute contact exposure to observe changes in response due to IMI.
Our experiments revealed that recordings from a fly antenna, conducted with electroantennography, allowed for differentiating between odors from heptane or an appetitive odor from Buddleja davidii flowers by analysing the response characteristics. Despite this, recordings from LPTCs did not reveal any uniform change in neuron spike rate when they were exposed to insecticides, odors or a combination of both. We did however observe that a vast majority of individual cells displayed a significant change in spike rate when they were treated with IMI or acetone, something that was not observed in the odor treated cells.
This paper serves to provides new insight into the environmental threat pesticides pose to the foraging behavior of E.tenax and to serve as a foundation for future research in the field of multimodal stimulation. (Less) - Popular Abstract
- Two Flies With One Pesticide.
Examining the brains of the hoverfly pollinator Eristalis tenax to understand the interplay between sight and smell and how anthropomorphic insecticides harms these agriculturally, ecologically and economically important insects through off-target action.
Anthropomorphic climate change has been central in the public eye for many years and with that we have seen an increase in interest and funding towards the study of our environment and different ecological systems. Through these studies it has become clear that the systems upholding balance in nature are much more complicated than we once believed and that we yet to this day do not have a whole picture of what makes or breaks ecosystems.
One key... (More) - Two Flies With One Pesticide.
Examining the brains of the hoverfly pollinator Eristalis tenax to understand the interplay between sight and smell and how anthropomorphic insecticides harms these agriculturally, ecologically and economically important insects through off-target action.
Anthropomorphic climate change has been central in the public eye for many years and with that we have seen an increase in interest and funding towards the study of our environment and different ecological systems. Through these studies it has become clear that the systems upholding balance in nature are much more complicated than we once believed and that we yet to this day do not have a whole picture of what makes or breaks ecosystems.
One key component in most ecosystems are believed to be insects. The small essential workers perform tasks such as disposing and breaking down organic matter to recirculate nutrients, serving as food for many other animals and serving as pollinators that aid plants to proliferate and produce much of the food we humans consume.
We have chosen to study one such beneficial insect, the hoverfly pollinator Eristalis tenax and to examine the effects of sub-lethal doses of pesticides on these essential insects.
To study these effects we recorded the spike firing rate of individual neurons within the brains of living insects and observed the changes that occurred when they were exposed to a common pesticide agent known as Imidacloprid. On top of that we wanted to investigate a phenomena that had been observed in other flies that revealed odors to be capable of amplifying the visual perception of flies.
Studying the effects of pesticides on the flies we initially did not see a significant change between before or after pesticide treatment. However, further dissection of the data revealed that a staggering 80% of the neurons that were exposed to pesticides presented a significant change in firing rate despite the population average change being insignificant. This revealed to us that the neurons we recorded may have wildly different ways of responding to pesticides with some having increased activity and others a decrease.
Odors did also not reveal a significant change in the population averages when comparing before and after presentation of odors. Examining the individual neurons we were however unable to detect a large number of individual neurons displaying significant effect, only observing a significant change in 10% of the neurons.
Insects have not originated to serve human interest and thus there exists groups of insects that are deemed harmful to the life of humans and animals, harmful to our food supply and harmful to our economy. Humans have, in response, designed mechanisms to control these pest insects through pesticides but have in the process inadvertently caused harm to the insects that are not harmful to us and that we so rely upon. To avoid serious harm due to these off target effects legislators and people using pesticides need pay serious attention to the science that has been done before a new pesticide is permitted for use. All too often it is only the dose required to achieve a lethal effect which is of concern, but what happens to the insects that receive a dose, yet do not die instantly, is of equal if not even more importance. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9113358
- author
- Lindberg, Navid LU
- supervisor
-
- David O'Carroll LU
- Elisa Rigosi LU
- organization
- alternative title
- Modulering av Riktningsselektiva Rörelsedetekterande Neuroner med Aptitliga Dofter hos den Pollinerande Blomflugan Eristalis tenax samt Effekterna av Akut Kontaktexponering av Imidacloprid
- course
- BMEM01 20231
- year
- 2023
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Eristalis tenax, Imidacloprid, Neonicotinoids, Lobula Plate Tangential Cells, Insecticides, Octopamine, Octopaminergic Modulation, Insect Vision, Insect Olfaction
- language
- English
- additional info
- 2023-04
- id
- 9113358
- date added to LUP
- 2023-04-17 13:33:52
- date last changed
- 2023-05-15 09:27:08
@misc{9113358,
abstract = {{Over recent decades, use of insecticides to protect plants from pests and harmful insects have increased manyfold.
Neonicotinoid insecticides, such as Imidacloprid (IMI) acts as partial agonists on nicotinic acetylcholine receptors which are widely present in both the central and peripheral nervous system of insects.
Pollinators like Eristalis tenax are frequently exposed to these pesticides but have been shown to also have a high tolerance to IMI, requiring high doses for it to be lethal.
Acute or chronic exposure to sub-lethal doses of IMI still presents a serious threat to the these flies as it may cause paralysis or other impairments such as impaired vision.
E.tenax relies on visual as well as olfactory cues to aid them in foraging and navigation and thus they may become unable to perform vital tasks or be exposed to predators.
In addition to vision, odor cues have long been known to be important for the proliferation of all kinds of animals. Studies on mosquitoes, fruit flies and blowflies suggests that stimulation to the olfactory system directly effects and modulates the visual system and is believed to do so through octopaminergic neurons.
This project's aim was to study the connection between sight and smell in the hoverfly pollinator E.tenax and to provide a basis for future research into this matter.
To achieve this we developed routines and systems for the testing of olfactory and visual stimulus simultaneously, on and off the influence of imidacloprid. We conducted in vivo extracellular recordings from Lobula Plate Tangential Cell (LPTC) type neurons in the third optic ganglion of E.tenax and observed the response to odor cues, visual cues and their interactive effects. We then exposed them to IMI through acute contact exposure to observe changes in response due to IMI.
Our experiments revealed that recordings from a fly antenna, conducted with electroantennography, allowed for differentiating between odors from heptane or an appetitive odor from Buddleja davidii flowers by analysing the response characteristics. Despite this, recordings from LPTCs did not reveal any uniform change in neuron spike rate when they were exposed to insecticides, odors or a combination of both. We did however observe that a vast majority of individual cells displayed a significant change in spike rate when they were treated with IMI or acetone, something that was not observed in the odor treated cells.
This paper serves to provides new insight into the environmental threat pesticides pose to the foraging behavior of E.tenax and to serve as a foundation for future research in the field of multimodal stimulation.}},
author = {{Lindberg, Navid}},
language = {{eng}},
note = {{Student Paper}},
title = {{Modulation of Direction Selective Motion Detecting Neurons by Appetitive Odors in the Hoverfly Pollinator Eristalis tenax and the Effects of Acute Contact Exposure to Imidacloprid}},
year = {{2023}},
}