Overgaard lab members

Principal Investigator

Johannes Overgaard, PhD


Department of Bioscience
C.F. Moellers Alle 3
Building 1134, Room 122
8000 Aarhus C
Denmark
biojo@biology.au.dk
 

 

My research interest has the common denominator: How have animals adapted to handle variability and extremes in environmental factors such as temperature, water- and food availability? Specifically I am interested in the interplay between physiological mechanisms and their ecological consequences in the form of energy and water balance, mortality, activity and distribution.

Current research topics include:
Physiological mechanisms underlying chill tolerance of insects and how this is linked to the preservation of ion homeostasis and neuro-muscular excitability.
Does cardiac capacity of fish and amphibians determine upper thermal tolerance and how are thermal limits affected by other factors such as hypoxia and digestion
How is energy and water balance maintained in gorge feeding ectothermic animals and how does energetic status and digestion interact with behavioural responses such as spontaneous activity and preferred body temperature.
What determines the upper thermal tolerance of small insects water loss, temperature or energy balance?


Postdoctoral Fellows

Heidi MacLean, PhD


Department of Bioscience
C. F. Moellers Allé 3
Building 1130, Room 118
8000 Aarhus C, Denmark

Insects are everywhere. They have adapted to live in some of the planet's harshest environments. I am interested in local adaptation and seasonal acclimation which have lead to this groups success and how climate change will affect this.
I am currently using different species of Drosophila to explore differences and consequences of seasonal acclimation.

Lucie Gerber, PhD


Department of Bioscience
C. F. Moellers Allé 3
Building 1130, Room 118
8000 Aarhus C, Denmark

Subject: The effect of low temperature on ion balance regulation in the migratory locust, Locusta migratoria


PhD Students

Mads Kuhlmann Andersen


Department of Bioscience
C. F. Moellers Allé 3
Building 1134, Room 123
8000 Aarhus C, Denmark
mads.andersen@bios.au.dk

 

My project aims to understand how membrane potential and ion- and water balance are affected by low temperature, and more specifically how these effects relate to chill coma; the reversible state of neuromuscular paralysis at low, but above freezing, temperatures. I plan to investigate this in insects with both a normal (e.g. Locusta migratoria) and abnormal (e.g. some species of Lepidoptera) ion balances. I further aim to study how the osmoregulatory organs and underlying mechanisms are affected by cold, and what role these effects play in determining insect chill tolerance as well as in entry into and recovery from chill coma. 

Jeppe

Jeppe Bayley


Department of Bioscience
C. F. Moellers Allé 3
Building 1130, Room 111
8000 Aarhus C, Denmark
jeppe.bayley@gmail.com

 

Subject: Mechanisms of chill injury and tolerance in locusts


Master's Students

Lisa Bjerregaard Jørgensen


Department of Bioscience
C. F. Moellers Alle 3
Building 1134, Room 124
8000 Aarhus C, Denmark
lisa.b.joergensen@gmail.com

My Master's project focuses on the effects of temperature on osmoregulatory capacity in five different locust species. The ability to maintain ion and water homeostasis over a range of temperatures is important to insects as ectotherms, and especially at low temperatures, it appears to be key to survival. Using a comparative system, I will examine water and ion transport over the rectal pads and Malpighian tubules.

Potræt.jpg

Christian Bak
 

Department of Bioscience
C. F. Moellers Alle 3
Building 1130, Room 111
8000 Aarhus C, Denmark

 

My goal is to understand why chill susceptible insects exhibit cellular injury and ultimately die when exposed to chilling temperatures. For my project I use Live/Dead-assays to examine if cell death occurs as a result of elevated extracellular potassium, cold exposure, or a combination thereof in vitro using muscle tissue from the migratory locust Locusta migratoria.

Mathias

Mathias Ravn
 

Department of Bioscience
C. F. Moellers Alle 3
Building 1130
8000 Aarhus C, Denmark

 

 

My project will investigate the changes in ion- and water balance during reversible anoxic coma in the locust Locusta migratoria. Furthermore, I intent to study the different factors contributing to these changes in homeostasis during anoxia, such as a drop in ATP production and pH changes, and I will investigate the effects of anoxia combined with other factors e.g. different temperatures.

Christian

Christian Ørskov
 

Department of Bioscience
C. F. Moellers Alle 3
Building 1130
8000 Aarhus C, Denmark

 

Insects such as Locusta migratoria are able to behaviorally regulate their temperature by actively seeking colder or warmer microclimates during the day and night. This phenomenon has been studied in the past but almost exclusively during daytime, using K-type thermocouples which don’t allow the locust a lot of freedom. I will be using small wireless transmitters which allow me to monitor the temperature of the locust every hour of the day and give the locust freedom to move around. Hopefully this will give a more complete estimate of the temperature preferences and behavior of the locust.

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Clayre Grumiaux
 

Department of Bioscience
C. F. Moellers Alle 3
Building 1134, Room 123
8000 Aarhus C, Denmark

Subject: "How and why Drosophila suzukii survive better under fluctuating thermal regimes than constant low temperature"


Undergraduate Students

Camilla

Camilla Grønkjær

Subject: Effects of cold and hyperkalemia on different tissues in Locusta migratoria

Christina

Christina Jensen

Subject: Comparing different species of locusts in regards to their response to cold exposure

Nikolaj

Nikolaj Skole Jensen

Subject: Chill coma in Drosophila melanogaster acclimated to different temperatures

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Marie

Subject: The effect of temperature on organisms used in biological control

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Jakob

Subject: The effect of temperature on organisms used in biological control


Previous Lab Members

Heath MacMillan - Postdoctoral Fellow (Website)

Jonas Andersen - PhD Student

Anders Findsen - PhD Student

Karina Vicents Fisker - PhD Student

Signe Overgaard Jensen - MSc Student

Trine Olsson - MSc Student

Julie Bjørge - MSc Student

Stefan Frey Gadeberg - MSc Student

Débora Claësson - MSc Student

James O'Sullivan - Placement Student

Branwen Messamah - Placement Student

Mikkel Ørnfeldt Nørgård - Undergraduate Project Student

Peter Søndergaard Schmedes - Undergraduate Project Student