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The smell of death and its effect on crucian carp with different personalities

Edbom Blomstrand, Cecilia (2019) BIOM02 20181
Degree Projects in Biology
Abstract
Communication in aquatic habitats commonly occurs via chemicals released from organisms. Chemical cues are used to detect prey and predators, and hence, play an important role in predator-prey interactions. Chemical cues from predators may induce morphological and behavioural responses in prey. For example, crucian carp (Carassius carassius) has demonstrated a morphologically induced defence with a deepening of the body and behavioural alternation such as activity decrease when exposed to chemical cues from predators. It has been demonstrated that bolder crucian carp induce a greater morphological defence than shyer conspecifics, leading to the question of whether boldness also affects prey behavioural response to chemical cues from pike... (More)
Communication in aquatic habitats commonly occurs via chemicals released from organisms. Chemical cues are used to detect prey and predators, and hence, play an important role in predator-prey interactions. Chemical cues from predators may induce morphological and behavioural responses in prey. For example, crucian carp (Carassius carassius) has demonstrated a morphologically induced defence with a deepening of the body and behavioural alternation such as activity decrease when exposed to chemical cues from predators. It has been demonstrated that bolder crucian carp induce a greater morphological defence than shyer conspecifics, leading to the question of whether boldness also affects prey behavioural response to chemical cues from pike (Esox lucius). In this study, three boldness assessments were conducted aiming to assess the personality of crucian carp. Two tests generated a repeatable gradient of boldness among experimental subjects and was further used to examine the effect of prey personality on an adaptive behavioural response (activity) towards chemical cues from a natural predator (pike). I used chemical cues from three individual pike that had been fed crucian carp and measured the activity pattern of personality-scored crucian carp before and after the introduction of cue containing water. My results show that crucian carp in general decrease their activity when exposed to pike cues, but I found no clear statistical relationship between the response behaviour and personality of crucian carp. When looking at the initial response (0-30 sec), however, individuals that were bolder in one of the boldness assays (scare test) showed a weaker reaction to the cue than their shyer conspecifics, indicating that shyer crucian carp has a lower threshold for chemical cues from pike, i.e. they are more responsive towards alterations in risk levels. Prey personality may therefore play a crucial part in predator-prey interactions but also in prey community structure, with boldness affecting prey behavioural responses. (Less)
Popular Abstract
Personality in crucian carp can affect their reaction to predator signals

Communication between organisms living in water commonly occurs via chemicals. These chemicals work as signals, sent from one individual to another. For instance, prey can pick up signals from nearby predators, allowing the prey to seek shelter or swim away before a potential attack. Some prey species are even known to demonstrate changes in their appearance when predators are present. Crucian carp (Carassius carassius) has shown that it can change its body type when exposed to pike chemicals for a long period of time. The body grows higher and works as a defence towards the pike since it is more difficult to eat high-bodied prey. It is also known that bold... (More)
Personality in crucian carp can affect their reaction to predator signals

Communication between organisms living in water commonly occurs via chemicals. These chemicals work as signals, sent from one individual to another. For instance, prey can pick up signals from nearby predators, allowing the prey to seek shelter or swim away before a potential attack. Some prey species are even known to demonstrate changes in their appearance when predators are present. Crucian carp (Carassius carassius) has shown that it can change its body type when exposed to pike chemicals for a long period of time. The body grows higher and works as a defence towards the pike since it is more difficult to eat high-bodied prey. It is also known that bold crucian carp increase their body height more than shy crucian carp. This raises the question of whether bold crucian carp react differently from shy ones behaviourally as well, when exposed to pike chemicals?

To test this, I first assessed the personality of 27 crucian carp. Three different boldness tests were used, and two of these showed a gradient of boldness for these individuals. However, it was not the same individuals that showed bold behaviour in both tests, which means that individuals can be bold according to one test, but not another.

So- will bolder crucian carp react differently to pike chemicals than shyer ones? I tested all the crucian carp by exposing them to pike chemicals and measuring their activity before and after the introduction of the chemicals. The crucian carp did indeed react to the pike chemicals that were added to the tanks; they decreased their activity significantly. The most dramatic change in behaviour occurred just after the pike chemicals were added. Bolder individuals according to one boldness test decreased their activity less in this initial period compared to shyer individuals. This indicates that personality in crucian carp affect their reaction to predator signals.

It is known that the presence of a predator affects prey behaviour and communities just as much as direct predation does. When considering these predator-prey interactions and their ecological importance, we should also include fish personality. Boldness is a trait that may affect prey communities crucially, with bold and shy individuals showing differences in morphological and now also behavioural defences to predator signals.

This study provides evidence that personality of fish can affect their reaction behaviour to predator signals. The study also gives an insight in the complexity of boldness assessment tests since here, the outcome differed between all three tests that were used. A standardisation of what kind of test to use could further help develop this research field and simplify comparisons between studies.

Master’s Degree Project in Biology, 30 credits, 2018
Department of Biology, Lund University

Advisor: Christer Brönmark, co-advisor: Jerker Vinterstare
Aquatic Ecology Department (Less)
Please use this url to cite or link to this publication:
author
Edbom Blomstrand, Cecilia
supervisor
organization
course
BIOM02 20181
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
8972734
date added to LUP
2019-03-12 10:09:29
date last changed
2019-03-12 10:09:29
@misc{8972734,
  abstract     = {Communication in aquatic habitats commonly occurs via chemicals released from organisms. Chemical cues are used to detect prey and predators, and hence, play an important role in predator-prey interactions. Chemical cues from predators may induce morphological and behavioural responses in prey. For example, crucian carp (Carassius carassius) has demonstrated a morphologically induced defence with a deepening of the body and behavioural alternation such as activity decrease when exposed to chemical cues from predators. It has been demonstrated that bolder crucian carp induce a greater morphological defence than shyer conspecifics, leading to the question of whether boldness also affects prey behavioural response to chemical cues from pike (Esox lucius). In this study, three boldness assessments were conducted aiming to assess the personality of crucian carp. Two tests generated a repeatable gradient of boldness among experimental subjects and was further used to examine the effect of prey personality on an adaptive behavioural response (activity) towards chemical cues from a natural predator (pike). I used chemical cues from three individual pike that had been fed crucian carp and measured the activity pattern of personality-scored crucian carp before and after the introduction of cue containing water. My results show that crucian carp in general decrease their activity when exposed to pike cues, but I found no clear statistical relationship between the response behaviour and personality of crucian carp. When looking at the initial response (0-30 sec), however, individuals that were bolder in one of the boldness assays (scare test) showed a weaker reaction to the cue than their shyer conspecifics, indicating that shyer crucian carp has a lower threshold for chemical cues from pike, i.e. they are more responsive towards alterations in risk levels. Prey personality may therefore play a crucial part in predator-prey interactions but also in prey community structure, with boldness affecting prey behavioural responses.},
  author       = {Edbom Blomstrand, Cecilia},
  language     = {eng},
  note         = {Student Paper},
  title        = {The smell of death and its effect on crucian carp with different personalities},
  year         = {2019},
}