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Tunnel vision: bumblebee (B. terrestris) flight behaviour as a response to visual cues in a two-choice tunnel experiment

Stelder, Jonno (2017) BIOM01 20171
Degree Projects in Biology
Abstract
Bumblebees (B. terrestris) were trained to fly through an experimental setup containing two tunnels which led to a single feeder. A variety of patterns were fitted onto the tunnel walls, each producing a different pattern of optic flow onto the retinae, in order to test for differences in flight behaviour and decision making as a response to the visual cues presented in the tunnels. The results showed a strong aversion towards tunnels that lacked longitudinal optic flow, through which flights were highly uncontrolled and significantly faster. Fairly controlled but slow flights were found in tunnels lacking any optic flow, presumably due to the bumblebees applying contrast adaptation. Tunnels providing strong optic flow cues were preferred... (More)
Bumblebees (B. terrestris) were trained to fly through an experimental setup containing two tunnels which led to a single feeder. A variety of patterns were fitted onto the tunnel walls, each producing a different pattern of optic flow onto the retinae, in order to test for differences in flight behaviour and decision making as a response to the visual cues presented in the tunnels. The results showed a strong aversion towards tunnels that lacked longitudinal optic flow, through which flights were highly uncontrolled and significantly faster. Fairly controlled but slow flights were found in tunnels lacking any optic flow, presumably due to the bumblebees applying contrast adaptation. Tunnels providing strong optic flow cues were preferred and showed highly controlled flights. Differences in response in terms of direction might be an indication that bumblebees utilize different sensory cues or strategies when commuting towards the nest or towards a food source. (Less)
Popular Abstract
How Visual Cues Affect Bumblebee Flight Behaviour

Bumblebee (B. terrestris) flight behaviour is primarily controlled by the visual cues that they receive from their surroundings. The pattern of image motion that is projected onto the retina, called optic flow, allows them to navigate and to control their flight. This study was designed to find out how different visual scenes that generate different optic flow cues affect the flight path choice of foraging bumblebees. Bumblebees were trained to fly through a tunnel setup that presented them with two visually different flight paths, forcing them to make a decision both when flying toward the feeder and when flying back to the hive.

The flight tunnels were fitted with three experimental... (More)
How Visual Cues Affect Bumblebee Flight Behaviour

Bumblebee (B. terrestris) flight behaviour is primarily controlled by the visual cues that they receive from their surroundings. The pattern of image motion that is projected onto the retina, called optic flow, allows them to navigate and to control their flight. This study was designed to find out how different visual scenes that generate different optic flow cues affect the flight path choice of foraging bumblebees. Bumblebees were trained to fly through a tunnel setup that presented them with two visually different flight paths, forcing them to make a decision both when flying toward the feeder and when flying back to the hive.

The flight tunnels were fitted with three experimental patterns which provided either a high level of optic flow cues, only optic cues in the vertical axis or no optic flow cues at all. A distinction was made between flights towards the feeder and flights towards the hive, to find out if bumblebees use different strategies between these flights. Changes in flight ratios between the two tunnels when the bumblebees were confronted with a different experimental situation were analyzed by taking previous experiences into account and also without these previous experiences.

The results showed that bumblebees avoid flying through tunnels with only vertical optic flow cues. Flights through these tunnels were fast and chaotic. When strong optic flow cues were present, flights were highly controlled and centred in the middle of the tunnel. Flying slowly allowed the bumblebees to still control their flight when no minimal optic flow cues were present. It was found that previous conditions still had an influence on tunnel choice when bumblebees were presented with new conditions. There were also differences in the path choice depending on whether the flight was towards or away from the feeder.

The aversion towards flying through tunnels that only produced vertical optic flow cues indicate that bumblebees need optic flow cues in the longitudinal axis in order to navigate. It was also clear that a lack of optic flow cues required the bumblebees to slow down to maintain control of their flight. This reduction of speed increases the sensitivity to contrast, a phenomenon called contrast adaptation, which allows the bumblebees to pick up on minuscule contrast cues which could provide them with the means to navigate effectively. The continuing effects from previous conditions indicate that bumblebees memorize visual elements during flight and that this influences their subsequent decisions. The differences in flight ratios between flights towards the feeder or towards the hive show that bumblebees navigate differently during these different types of flight. Further studies are needed to uncover what actually causes these differences.

This study made it clear that visual cues affect the flight path choice of bumblebees. These findings can improve our understanding of foraging behaviour in bumblebees or related species, pollination efficiency and potentially aid the conservation efforts of related species which are currently under threat.

Master’s Degree Project in Biology, 30 credits
Department of Biology, Lund University
Advisor: Emily Baird
Lund Vision Group, Department of Biology (Less)
Please use this url to cite or link to this publication:
author
Stelder, Jonno
supervisor
organization
course
BIOM01 20171
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
8925085
date added to LUP
2017-09-08 13:39:05
date last changed
2017-09-08 13:39:05
@misc{8925085,
  abstract     = {Bumblebees (B. terrestris) were trained to fly through an experimental setup containing two tunnels which led to a single feeder. A variety of patterns were fitted onto the tunnel walls, each producing a different pattern of optic flow onto the retinae, in order to test for differences in flight behaviour and decision making as a response to the visual cues presented in the tunnels. The results showed a strong aversion towards tunnels that lacked longitudinal optic flow, through which flights were highly uncontrolled and significantly faster. Fairly controlled but slow flights were found in tunnels lacking any optic flow, presumably due to the bumblebees applying contrast adaptation. Tunnels providing strong optic flow cues were preferred and showed highly controlled flights. Differences in response in terms of direction might be an indication that bumblebees utilize different sensory cues or strategies when commuting towards the nest or towards a food source.},
  author       = {Stelder, Jonno},
  language     = {eng},
  note         = {Student Paper},
  title        = {Tunnel vision: bumblebee (B. terrestris) flight behaviour as a response to visual cues in a two-choice tunnel experiment},
  year         = {2017},
}