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The search for rotifers continues

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“Thank you”, I whispered in a soft voice while driving by the rayon and plating factories surrounding Lake Orta. “Thank you for giving me a PhD”.

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Brachionus calyciflorus

The wastewater of those factories polluted the lake with copper and ammonium sulphate from approaching the mid-nineteen hundreds until the end of the last century. This history of pollution makes Lake Orta an interesting ecosystem to study, and sets the perfect stage for my PhD: the life-history responses of the rotifer Brachionus calyciflorus to past environmental changes (i.e. industrial pollution) and the underlying eco-evolutionary processes.

To study this, I (try to) resurrect rotifers from up to 80 year old lake sediments that contain their resting eggs, and compare the performance of these rotifers under different experimental treatments. As I have had some difficulties getting resting eggs from the post-pollution conditions, I decided to go to Lake Orta to get the most recent Brachionus calyciflorus: the ones that are currently swimming around.

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Sampling Lake Orta with a plankton net.

Together with Diego Fontaneto of the ‘Istituto per lo Studio degli Ecosistemi’, I drove around the lake, and found five spots to easily enter the lake to collect zooplankton with a plankton net. This net made of fine nylon mesh is pulled through the water horizontally and the animals are captured in a vial at the bottom of the net.

A quick look together with Diego revealed that we captured tons of animals, but probably no Brachionus. A more thorough look together with our summer research assistant Conor Waldock confirmed this suspicion, but we have still some bottles of water to go through, so we keep on hoping. And otherwise, our hope lies in the sediment samples of Lake Orta that I also brought back from the trip.

The reason why we didn’t find any Brachionus in our water samples? Probably because the water was still too cold due to the relatively bad summer, and there have been no big algae blooms yet of which Brachionus could profit. I guess this means I have to go back next month to again sample Italian ice cream… Ehm, Lake Orta I mean.

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Diego Fontaneto (left) and Conor Waldock looking at the harvest of the sampling day: water and mud.

Thinking hard and digging deep is facilitated by isolation

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‘Think hard and dig deep, without being canalized by the ideas of others published in literature. Not very often do you get a chance like this offered to you. Take the challenge.’ And all the students participating in the Guarda Evolutionary Biology course took the dare set by Dieter Ebert, Sebastian Bonhoeffer, David Queller, and Joan Strassmann.

DSC04117In the idyllic Swiss village of Guarda, twenty-eight MSc/PhD-students interested in evolutionary biology were selected for a week of isolation, and given time to devote themselves to writing a grant proposal on any question they thought was worthwhile pursuing. The only requirements were that you had to collaborate in a group of 4-5 students, and choose a topic that was not related to your field of research at all. Oh, and you were not allowed to look for information in books or on the Internet: it was only tolerated to use the creativity of your own mind, the mind of your fellow students, and of the faculty members.

In just 15 working hours, the first draft of the grant proposal (including idea, hypotheses, and well-thought out experiment) had to be handed in. The faculty members granted every group 20 minutes to undergo their severe but justified feedback on the proposal. Six working hours after this feedback, the revised version had to be handed in, which got another feedback round. Five hours after this round, the final version and a presentation had to be ready. On top of that, there was an armchair lecture by one of the faculty members every evening, and you were (happily) obliged to offer all of them a hand cooked dinner during one of the days in the week.

DSC04061This has been one of the most inspiring courses I ever took that has brought me back to basic scientific thinking: What is an interesting and important question in (evolutionary) biology? How would you solve that question? Is your hypothetical experiment really answering that question? Does working within a group of complete strangers full of enthusiasm facilitates the brainstorming, discussing and writing-up process, or do you might have to learn a lot in how to successfully listen, be open-minded, and collaborate?

After this highly motivating and encouraging course (e.g. why not embrace serendipity in your scientific work?), we got home extremely exhausted, to find out that the project we proposed was at the moment being presented at the big Evolution meeting in North Carolina: how mutualistic interactions could alter the dynamics of natural selection.  I think that’s what you call Zeitgeist.

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Photo by Joan Strassmann

Second field season started at the Alpine Marmot Project

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Welcome back to the Natural Reserve of La Grande Sassière where the second field season on alpine marmots started 3 weeks ago. Whereas last year at the same period there was deep snow (1m40), we arrived in an almost snow-free area.

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As some of you enjoyed the mild winter, it seems that the marmots did too. Survival rate of the juveniles has never been that good: we already caught 90% of them! Even the lightest one, that was 165g last year survived: it is now 900g and it is running and playing all around with its 4 brothers and sisters!

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To deal with energy limitation, individuals have to adjust their energy balance (energy acquisition vs. energy expenditure) to maintain their homeostasis and maximize their fitness. Among all mechanisms, thermoregulation represents the highest energetic cost in endotherms. My research project focus on the role of hibernation in the life history of the marmot. To understand how hibernation patterns are adjusted to environmental conditions, we are following the body temperature of 33 individuals since May last year with loggers placed in the intra-abdominal cavity. We already caught 20 of them. Cannot wait to download the data from these loggers! Some preliminary results below… Looks great, does not it!

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Have a look to our blog in 3 weeks to know how the field session ended, and come back in few months to know more about the mechanisms underlying critical trait-demography relationships of the Alpine Marmot!

Attendance ‘Bayesian population analyis using WinBUGS’-course

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‘Don’t feign to be stupid.’ This well-chosen phrase of Marc Kéry introduced some of our group members to the world of Bayesian Statistics (where the use of your previous knowledge on the parameter you’re interested in, the prior distribution, plays a role). Together with Michael Schaub, Marc taught the inspiring course entitled ‘Bayesian population analysis using WinBUGS’ based on the book of the same name.

I was impressed by how they managed to cover almost the whole book within 5 days: starting with a gentle introduction to the analysis of distribution, abundance and population dynamics using a Bayesian framework, followed by an introduction to the software WinBUGS and implementation of mixed models in it, and finishing with some examples of the implementation of Integrated Population Models in WinBUGS. Lectures were alternated with useful exercises.

I think all the participants are after this course better trained in making a balanced decision whether they want to make use of the full knowledge they have, or use the veil of stupidity to make big discoveries (Schwartz, 2008).

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Take your time, settle down, if you want you can…return

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Well, sometimes it is about fathers and sons, but sometimes it is also about sisters and unrelated males to find each other and settle down…

Three months after the beginning of our fieldwork we finally recorded our first long-range dispersal event. Following aggressive eviction from the natal group, a dispersing coalition of five subordinate females joined a group of unrelated roving males and left the core study area. The newly- formed group went undetected for several weeks until Nino found one of the coalition members (VLF152) …back on the reserve where she was captured and collared 5 weeks before. Interestingly enough she wasn’t with any of her original coalition partners and instead paired up with two newly evicted sisters.

Dispersal event of one female (VLF152) from the five-members dispersing coalition showing a typical migration pattern (see Bunnefeld et al. 2011, Börger and Fryxel 2012) as represented by the increasing and subsequent decreasing distance from the site of capture (origin). VLF152 returned home after a 25 km round trip lasting 31 days. The other four coalition members have not returned and possibly established a new territory (red circle), following a typical dispersal pattern (left side of the blue dotted line) characterized by departure (1) roaming (2) and settlement (3).
Dispersal event of one female (VLF152) from the five-members dispersing coalition showing a typical migration pattern (see Bunnefeld et al. 2011, Börger and Fryxel 2012) as represented by the increasing and subsequent decreasing distance from the site of capture (origin). VLF152 returned home after a 25 km round trip lasting 31 days. The other four coalition members have not returned and possibly established a new territory (red circle), following a typical dispersal pattern (left side of the blue dotted line) characterized by departure (1) roaming (2) and settlement (3).

But where were the other four sisters? Did the coalition simply split or did the other die? Or did they settled down somewhere with the males? But if so, why did VLF152 “return home” instead or remaining within them? Is this because, even within the new group, she was occupying a low rank and had therefore no chance of reproducing (for only one female, the dominant female, reproduces within a group)? We are currently trying to find the other four females to answer some of our questions. Knowing the where about of VLF152 – information that we can remotely download from her GPS collar – should help in this task since we can restrict our search radius.

This dispersal event adds to the previously collared individuals. At present, three dispersal coalitions returned to the natal group, one female returned to the natal group after her coalition partner got hit by a car but got evicted again, three coalitions are still dispersing and one single disperser got predated by a raptor. We thus recorded two cases of dispersal-related mortality. These movement data will allow us to investigate the influence that individual traits (e.g. age, size) but also the environment and the social spatial context (i.e. the distribution of territorial groups) have on dispersal patterns and dispersal success (survival rate and settlement likelihood).

Preliminary movement data from eight dispersing coalitions fitted with GPS radio collars. Each color represents the trajectory of a different dispersing unit in (A) the environmental landscape and (B) the social context. Note the long-range dispersal event southwest of VLF152 (violet/pink)! In (B) a utilization distribution map for the main study area is created based on the location of territorial groups (warm color= high encounter likelihood, cold colors= low encounter likelihood); long range dispersal event may end in areas where the social context is unknown (white)
Preliminary movement data from eight dispersing coalitions fitted with GPS radio collars. Each color represents the trajectory of a different dispersing unit in (A) the environmental landscape and (B) the social context. Note the long-range dispersal event southwest of VLF152 (violet/pink)! In (B) a utilization distribution map for the main study area is created based on the location of territorial groups (warm color= high encounter likelihood, cold colors= low encounter likelihood); long range dispersal event may end in areas where the social context is unknown (white)

!!!   Merry Christmas from us all and a successful 2014   !!!

Gabriele receives the ZGZ Price for Nature and Environmental Protection

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This Tuesday, Dr. Gabriele Cozzi gave a public talk at the Zurich Zoological Society about his PhD work on wild dogs, hyenas and lions in Botswana, and in collaboration with  the University of Zurich and the Botswana Predator Conservation Trust :

“Mit Katzen (nicht) kommunizieren: ein Hundeleben”

“In (no) communication with cats: A dog’s life”

At the end of his talk, Gabriele received the prestigious Price for Nature and Environmental Protection (2013) in recognition of his contribution to wildlife conservation in Africa. Congratulations to Gabriele for this well-deserved award!

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If everything else fails, try Triops

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Sometimes Science is nothing more than checking assumptions. This holds true whether you are a theoretical biologist (e.g. checking model assumptions), experimental biologist (e.g. checking assumptions of experimental design), or just love doing statistics (as we all do). During the first weeks of my PhD, I found out that I perhaps needed to check the basic assumption my supervisor has about me: that I would be able to let eggs hatch in the lab. Until now, I have been unable to let the desired rotifer eggs hatch, but I can proudly announce that since five days we have some pets in our office: Triops! These crustaceans are considered ‘living fossils’, and just as the rotifers I’m investigating, their eggs can remain in a state of diapause for a prolonged period of time.

Assumption “I have the capacity to let resting eggs hatch under laboratory conditions”: Check!

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Triops X, one of our new office pets
Triops X, one of our new office pets

When Claude meets Charles…

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“Claude Bernard and Charles Darwin, two geniuses from 19th century, initiated each in their own way and from disjoint areas, the contemporary biological revolution.
Physiological ecology is born from the convergence of their views and now evolves since the appropriation of the news tools such as molecular and cell biology, proteomics, ecotoxicology and isotopic chemistry. The main purpose of this biological discipline is to integrate physiological processes in the ecology and evolution concepts.” website

This is what drives me to Lyon (France) the last week to participate to the 1st Symposium of Animal Physiological Ecology.
It was a really interesting meeting with scientific talks of high quality.
Different topics have been discussed showing the multidisciplinarity of Physiological Ecology:
– Adaptations to extreme conditions
– Anthropogenic stress
– Behavior
– Genome, allocation, life history traits
– Pathogenesis and Parasites
– Physiological Ecology and Conservation

I gave a talk on the importance of physiological flexibility in a changing world and hope to present data on alpine marmots in 2 years at the 2nd Symposium of Animal Physiological Ecology!

 

Are the marmots fat or muscled?

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While some are tracking meerkats in South Africa, others are developing complex models in Zurich, I was doing laboratory work at the “Institut Pluridisciplinaire Hubert Curien” in collaboration with the Evolutionary EcoPhysiology Team (Strasbourg, France).

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No, no,no, I am not playing with liquid nitrogen for fun…
I am doing cryo-distillation to isolate water from biological fluids (here blood samples).
You probably wondering:  What? or Why ? I would answer because we want to demonstrate that:

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In other words, we want to validate the bioelectrical impedance analysis (BIA) by the deuterium dilution method to measure the body composition of marmots.
The bioelectrical impedance measurement is a non invasive method to estimate body composition and in particular body fat by determining absolute fluid volumes. It is doing exactly the same than the new scale you have at home! It is based on the fact that an electric current is conducted poorly by fat and bone but conducted well by tissues containing electrolytes and water.
BIA has been used in a number of species to evaluate total body water and thus body composition, including humans, cats, harbor seals, bear, dogs, pigs, horses but never used in marmots before.

So to ensure that this method is also appropriate in marmots, we evaluate the total body water by deuterium concentrations in condensed water from blood sample.

For more informations, you can read:
Kyle UG, Bosaeus I, De Lorenzo AD, Deurenberg P, Elia M, Gómez JM, Heitmann BL, Kent-Smith L, Melchior J-C, Pirlich M (2004). “Bioelectrical impedance analysis—part I: review of principles and methods.” Clinical Nutrition 23(5): 1226-1243. pdf