Resource Fluctuations and Animal Movement

Resource Fluctuations and Animal Movement

Resources fluctuate in their availability daily, seasonally and sometimes unpredictably. We are interested in the strategies animals have developed to deal with resource fluctuations, especially long and short distance movement, and how this can be optimized by social information transfer and alternative strategies in animals that cannot follow resources in space.

See below for project overviews.

Current Lab News

Phd student wanted for the  project on seasonal brain size changes in shrew

Phd student wanted for the  project on seasonal brain size changes in shrew

In our long-term project on the evolution of reversible individual size changes in small high-metabolic mammals we have an open position for a 3-year PhD starting as soon as possible but hopefully before June this year. You would be working with captive shrews and study them as they go through the size changes in the brain using a combined approach of repeated state-of-the-art MRI imaging and behavioural assays of the same individuals. The MRIs will be done in the group of Dominik von Elverfeldt in Freiburg, where you will spend part of your time (https://www.uniklinik-freiburg.de/mr-en/members/current/elverfeldt.html).

This is a HSFP-funded collaborative project with Liliana Davalos from Stony Brook University (looking at the molecular basis of this phenomenon) and John Nieland from Aalbord University (looking at the lipid metabolism) and their students.

What we are looking for:

If you are fascinated by evolution and questions such as how seasonal change affects animals, how the brain is shaped by evolutionary pressure, or how brain size is linked to behaviour and cognitive abilities this may be the right position for you.  You need to be enthusiastic about working in a team and sharing data.

Ideal would be if you are a biologist with also a background in or inclination for physics or bioimaging as the MRI (which we will be the first to do with shrews) will be a large and important part of the project. Good English skills are also a requirement.

What you will find:

The Max Planck Institute for Ornithology is a thriving center for research on animal behaviour and our group has been working on these shrews for years, working out many (but not all) of the potential kinks of working with the sensitive shrews. Our graduate school IMPRS for Organismal Biology provides added background where you can profit from a large spectrum of courses and support.

Interested? Please send your CV, a motivation letter and a research statement to ddechmann@orn.mpg.de by May 15th.

more info on us and the project: https://www.orn.mpg.de/641895/Sociality-and-Movement

Let Teague tell you why large numbers of fruit bats are crucial.

The crucial role of fruit bats for African forest ecosystems: new paper out on quantitative estimates of seed dispersal by our Eidolon

The crucial role of fruit bats for African forest ecosystems: new paper out on quantitative estimates of seed dispersal by our Eidolon

That frugivores are important seed dispersers is no big news. Our new paper introduces a quantitative model estimating how long gut retention, huge foraging distances and large colony size of the African straw-coloured bat lead to unique and impactful seed-dispersal at a landscape level
https://doi.org/10.1016/j.cub.2019.02.033

See below for past lab news.

Project Overviews

Eidolon may (still) be the most numerous mammal of Africa and yet what we know about this bat barely scratches the surface. We study the unique long-distance migration of this species in one of the ICARUS pilot projects. We aim to understand how this massive movement across the African continent is driven by environmental factors, but facilitated by exploding information networks of gigantic colonies informing individual decisions. By feeding our data and conclusions into studies about the spread of diseases of human concern, this will also contribute to understanding the actual role fruit bats play in this urgent topic.

We study bats that are highly specialized on ephemeral resources. How does the availability of resources in time and space affect foraging efficiency? How are these foraging challenges overcome through information transfer by different modalities? And finally how is this linked to the metabolism and physiology of the bats?

Most of our work focuses on bats, which fly and can cover distances up to several thousand kilometers to escape food shortage or harsh conditions. But what does a small temperate-zone mammal do when seasons present environmental challenges? In a project focusing on red-toothed shrews, we study Dehnel's Phenomenon - a reversible individual size change that includes mass, size, the skull, several major organs and especially our focus - the brain.

Out today: our new paper about flight altitudes of foraging bats
We used miniaturized pressure sensitive transmitters to determine the flight altitude of common noctules with very high temporal and spatial accuracy - see how they fly over lake Constance!

more
<h3>Migration and metabolism of the common noctule</h3>

Migration and metabolism of the common noctule

The common noctule (Nyctalus noctula) is the one species where we combine the link of long- and short-distance movement and sociality. All European bats that have long-distance migration at all are sex-dimorphic in this behavior with only the females migrating or migrating longer distances. This means that in addition to the energy demanding reproductive period they also need to power migration and to fit all this into the brief time between hibernation periods.

Past Lab News

The shrew project receives a huge boost: we have been selected for a collaborative grant from Human Frontiers, together with Liliana Davalos from Stony Brook and John Nieland from Aalborg

The shrew project receives a huge boost: we have been selected for a collaborative grant from Human Frontiers, together with Liliana Davalos from Stony Brook and John Nieland from Aalborg

Organisms need strategies to survive when conditions are hard. For mammals, winter is particularly difficult - they have to invest large amounts of energy into keeping warm, while food availability is low. For this reason, many mammals migrate or hibernate. However, what to do if you are too small to migrate long distance, burn your energy fast, and cannot hibernate? The common shrew is such a mammal and has evolved an astonishing strategy: each individual shrinks in winter by up to 20% and then regrows in the spring by about 13%. This size change, thought to allow shrews to survive on fewer resources because of the smaller size and linked lower energy requirements, include not just overall size, but specifically organs that do not usually change size in fully grown animals, such as the brain, heart and liver.

The process of neurological degeneration and regeneration is of great interest, since many central nervous system diseases (e.g., Alzheimer’s, multiple sclerosis) involve degeneration, but ongoing research for therapies to reverse this process has been of limited success. As one of only a few recorded examples of mammalian brain regeneration, understanding how the shrew regrows its brain can accelerate research that leads to future therapies.

To answer the question of how the shrew shrinks and then regrows its brain, we will establish this unusual species as a new model, by studying the biological, molecular, biochemical and genetic processes behind this reversible size change. Besides establishing a database of information that can be mined and researched in years to come to discover the pathways that generate this cycle in the shrew, we will test a metabolic model of neurological change by artificially blocking molecular access to fats. Thus, the cross-disciplinary study of this wintering adaptation may help us understand more about regeneration in mammals in general, and the brain in particular.

Bat season has started

Bat season has started

Lara is kicking of the first field season of her PhD - bat box checks on a chilly March morning with some sleepy noctules
Out today: our new paper about flight altitudes of foraging bats
We used miniaturized pressure sensitive transmitters to determine the flight altitude of common noctules with very high temporal and spatial accuracy - see how they fly over lake Constance!

more
Javi's new paper about the amazing flexibility in the seasonal reversible size changes of our shrews is out!<br />https://www.nature.com/articles/s41598-019-38884-1
Shrews are extreme - this much is clear already. But they continue to amaze us as we dig deeper. In this study we investigated whether we could modify the regular pattern of size change in the skull of the common shrew: shrinking in autumn and regrowth in spring. And indeed by changing a single variable - ambient temperature - the cycle gets completely disrupted. See what else we found in this recent paper! more
Jenna's erstes Paper über ein bisher noch nicht gesehenes Verhalten in der Gelbohr-Fledermaus ist veröffentlicht!
As the only flying mammals, bats have numerous unique life history traits. One of these traits is how quickly pups must grow up, but now we’re learning about the specific behaviors both pups and mothers use to deal with this rapid transition. And they’re as unique as the bats themselves.
Curious? Here is the Link to the paper: more

Here is a link to a short clip about the interesting behaviour between mothers and pups

Dina tells about her shrew research at FENS 2018 in Berlin (from 15:46 minutes)

Noctule spring migration tracking

Noctule spring migration tracking

Spring migration has ended for our Noctules. With a big group effort we tracked several individuals for insights into migration flight altitude. We were also joined by a tenacious film crew hoping to capture the action.
First noctules of the year!

First noctules of the year!

We completed our first bat box checks in Bischofszell and Frauenfeld in spring 2018 and found many noctules preparing to migrate, 47 bats in one box alone!
Herzlichen Glückwunsch zum Doktortitel, Javi!

Congratulations, Javi!

Our Shrew-Crew member Javier Lazaro successfully defended his PhD with the title “Causes and consequences of seasonal changes in the braincase and brain size of the common shrew Sorex araneus” on the 15.3.2018. Congratulations, Javi!
Max-Planck Highlight 2017: Schrumpfende Spitzmäuse!

Max-Planck highlight 2017: Shrinking shrews!

Our research on shrews counts to the highlights 2017 of the Max-Planck Society! Click here to check out other interesting findings and research topics which are the most important ones of 2017: https://www.mpg.de/research-highlights-2017
Check out the newest paper from Javier Lazaro in Journal of Experimental Biology!
Congratulations Javi for your next paper about shrews with the title "Cognitive skills of common shrews (Sorex araneus.) vary with seasonal changes in skull size and brain mass". more
<span>Welcome Francisco!</span>

Welcome Francisco!

Francisco Amorim from Portugal is visiting our lab for one month and already gave us a great talk about "The importance of (bat) monitoring: From windfarms to optimized monitoring networks". 
Congrats Dina and Teague to the second paper out this week!

Congrats Dina and Teague to the second paper out this week!

In Biology letters you can read more about a European bat species, the common noctule Nyctalus noctula and how it decides to migrate.
Here are the links: 
https://phys.org/news/2017-09-optimal-weather-conditions.html
http://rsbl.royalsocietypublishing.org/content/13/9/20170395
Congrats, Teague O'Mara for his recent paper on the energetic strategies of tent-making bats in eLife!

Congrats, Teague O'Mara for his recent paper on the energetic strategies of tent-making bats in eLife!

A collaboration across 6 institutes in 4 countries allowed the scientists to see intimate details about the way these bats lower their hearts rates in 5 minute cycles when they rest during the day - something really unusual!
Check out the paper: https://elifesciences.org/articles/26686

Lab Retreat to Prata!

Lab Retreat to Prata!

A weekend in the Italian Alps for proposal writing and discussion, but lots of laughter, good food, and puppy love too.
Plenary talk at TiBE 2017 Bio-logging
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Plenary talk at TiBE 2017 Bio-logging  

Dina invited as key note speaker for Trends in Biodiversity and Evolution's annual meeting in Vairão, Portugal for the theme bio-logging, and shares about the challenges of studying bats!
Advanced Course "Going Wild"

Advanced Course "Going Wild"

During the past 6 weeks, 12 masters students from Universität Konstanz joined the Dechmann lab to track migrating noctules for the course "Going Wild" hosted by the institute! 

Goodbye, Sharon Swartz!

Goodbye, Sharon Swartz!

Our sabbatical guest Sharon Swartz and her husband Eric have been a part of our group for the past nine months. Thank you for many inspiring discussions, expert advice and wonderful company. You will be deeply missed! 
As a farewell outing we visited the Seealpsee and Ebenalp in Appenzell.
Yearly spring batbox checks in April!

Yearly spring batbox checks in April!

Every spring and autumn we check bat boxes in Kreuzlingen, Frauenfeld and Bischofszell.

 

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