Thorbjörn Sievert

Thorbjörn Sievert
University of Liège | ulg · GIGA-Neurosciences Unit

Doctor of Philosophy
I am actively looking for PostDoc opportunities with chemical communication in mammals! Feel free to reach out!

About

11
Publications
2,736
Reads
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84
Citations
Citations since 2016
10 Research Items
84 Citations
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Introduction
PhD student working on predator-prey interactions between Bank voles and Least weasels. Main focus is on olfactory cues and trans-generational effects of predator exposure.
Additional affiliations
June 2014 - May 2015
Linköping University
Position
  • Master's Student
Description
  • Behavioural responses of mice to predator odour components
August 2013 - July 2015
Linköping University
Position
  • Master's Student
April 2013 - June 2013
Research Museum Alexander Koenig
Position
  • Bachelor thesis
Education
May 2016 - May 2020
University of Jyväskylä
Field of study
  • Predator-prey interactions between Mustela nivalis and Myodes glareolus
August 2013 - June 2015
Linköping University
Field of study
  • Applied Ethology and Animal Biology
October 2010 - July 2013
University of Bonn
Field of study
  • Biology

Publications

Publications (11)
Article
Full-text available
Prey animals can assess the risks predators present in different ways. For example, direct cues produced by predators can be used, but also signals produced by prey conspecifics that have engaged in non-lethal predator-prey interactions. These non-lethal interactions can thereby affect the physiology, behavior, and survival of prey individuals, and...
Article
Full-text available
Chemical communication plays an important role in mammalian life history decisions. Animals send and receive information based on body odour secretions. Odour cues provide important social information on identity, kinship, sex, group membership or genetic quality. Recent findings show, that rodents alarm their conspecifics with danger-dependent bod...
Article
Full-text available
Most small rodent populations in the world have fascinating population dynamics. In the northern hemisphere, voles and lemmings tend to show population cycles with regular fluctuations in numbers. In the southern hemisphere, small rodents tend to have large amplitude outbreaks with less regular intervals. In the light of vast research and debate ov...
Article
Full-text available
Authors would like to correct error in affiliation in the original publication of the article.
Thesis
Full-text available
Predator-prey interactions are a major evolutionary driver, affecting not only the direct mortality of prey species, but also their behaviours and reproduction. Prey species behavioural adaptations aim to mitigate the effects of predation and to maximise survival and individual fitness. These adaptations include the ability to signal a threat to co...
Article
Full-text available
In the predator–prey arms race, survival-enhancing adaptive behaviors are essential. Prey can perceive predator presence directly from visual, auditory, or chemical cues. Non-lethal encounters with a predator may trigger prey to produce special body odors, alarm pheromones, informing conspecifics about predation risks. Recent studies suggest that p...
Article
Full-text available
Risk recognition by prey is of paramount importance within the evolutionary arms race between predator and prey. Prey species are able to detect direct predator cues like odors and adjust their behavior appropriately. The question arises whether an indirect predation cue, such as the odor of scared individuals, can be detected by conspecifics and s...
Article
Full-text available
Climate change, habitat loss and fragmentation are major threats for populations and challenge for individual behavior, interactions, and survival. Predator‐prey interactions are modified by climate processes. In the northern latitudes strong seasonality is changing and the main predicted feature is shortening and instability of winter. Vole popula...
Poster
Full-text available
In the evolutionary arms race between prey and predator, early risk recognition by the prey species is of paramount importance. Mammalian prey species are able to detect direct predator cues, like odors and to display appropriate defensive behaviors. Not much is known about indirect predation cues in mammals, i.e. the scent of scared individuals de...
Article
Mammalian prey species are able to detect predator odors and to display appropriate defensive behavior. However, there is only limited knowledge about whether single compounds of predator odors are sufficient to elicit such behavior. Therefore, we assessed if predator-naïve CD-1 mice (n = 60) avoid sulfur-containing compounds that are characteristi...
Thesis
Full-text available
Having means to detect and avoid potential predators is a necessity for prey species. Most mammalian prey species are able to detect odours emitted by predators and to adapt their behaviour accordingly. These odour cues are therefore considered to act as semiochemicals. Predator odours consist of several dozen different odourants. In order to asses...

Questions

Questions (3)
Question
Hey,
I'm planning an experiment to pinpoint which chemical(s) from a group of 10 components is/are causing an observed ecological effect.
Unfortunately there is no data which chemical is more or less likely to be relevant.
(Edit: To avoid confusion, this is not a question about pollution in aquatic systems, but about odours causing a behavioural response.)
The plan is to have different mixes of the chemicals as my treatments. Each mix will contain eg 4 of the chemicals in different combinations.
The concentration of each component will be constant, the difference will just be a binary 0 or 1 whether it is present or not.
Question 1: Is there a name for this kind of procedure so that I can read up on it?
Question 2: Are there ways or best practices how to design my mixes, i.e. how many different ones and how many components in each.
Question 3: What would be the best way to analyze this? As far as I've read it could potentially be done with a logistic PCA, NMDS or SIMPER analysis, but I cannot figure out which one would be best.
Question
We are using Giving Up Densities to determine the perceived risk in voles.
This is a forced choice setting, with 3 different foraging patches, each with their own risk level.
Some individuals started to forage in the "dangerous" patches and store it in the "safe" patches, bringing them above their initial food levels.
How do I account for this in the statistics?
We are going to report proportions (food remaining/food initially), so that values should range between 0 and 1, however the latest individual stored so much food that it pushes the value to 1.2.
My idea was to either force a cut-off at 1, or to subtract the additional food, i.e. turn the 1.2 into 0.8.
Neither option seems perfect.
Thanks in advance!
Question
I am aware of the crown index and parameters for whole forest areas, but what can be used for single saplings?

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Projects

Projects (2)
Project
This is a long-term project and interest for me where I try to investigate to existence and extent of chemical alarm communication (alarm secretions, alarm cues, alarm pheromones) in mammals. Feel free to contact me if you want to cooperate!
Archived project
1) right recognition and cognitive processes in detection of increased predation risk of olfactory fear signals in boreal small rodent prey and fear effects in behavior and stress physiology 2) over-generational fear effects in behavior and reproduction in field experiments