Back to Panama, for the fifth fieldwork season of data collection of my PhD. I have three determined goals for this session : (i) collecting survival data, (ii) collecting DNA samples and (iii) manipulating group size. This is the third consecutive season where I am catching a network of a dozen roosts where I can determine group size.
During captures, animals are marked individually with transponders. With relevant statistical analyses, I will try and estimate survival based on recapture rates and detection probabilities. My species foraging in groups, group size probably has an effect on individual survival, that’s what we are trying to determine with these analyses. In parallel, I am collecting wing biopsies. These DNA samples will be genotyped to obtain microsatellites. They will be used to study relatedness of individuals within groups. I am especially interested in male reproductive success in function to group size. I assume it will be more difficult for the dominant male to insure paternity in groups with more females. And the main goal of this mission is to study the foraging efficiency (weight gain relative to time spent out of roost) in function to group size. Several roosts studied are equipped with automated systems with automated transponder reader and integrated scale. To investigate the effect of group size, I am comparing foraging efficiency for a group of normal size and of modified size. To modify group size, I capture individuals of the group that I keep for several days in captivity. Captive individuals are fed each night with mealworms and released within few days. I have already manipulated three groups, a fourth is ongoing and a fifth will come in the days to come. I have now collected a lot of data, in parallel I am now working on the analyses.
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I stayed a short month in Panama this summer – from mid-July to mid-August. The priority was to catch all the colonies we work on – more than 20 nights of catching for a total of around 300 bats. Many new bats have been transpondered and I have collected a lot of DNA (relatedness analysis) and feces samples (virus and diet studies). The highlight of the stay was the catch of 96 bats in one night. The catch started at 6PM and we finished processing the bats around 6AM.I had a small army of people from the batlab to help me – thanks to Teague, Basti, Julia, Sebas, Michelle, Toni, Santi, Dallas…
Unfortunately, three of the roosts with automated monitoring systems were abandoned (probably due to house renovation) but we installed two other automated monitoring systems. I also had the opportunity to present my PhD project to the scientific community – good practice with a lot of interesting questions. In addition, I helped Sebas for a parallel project. As a pilot study for his master thesis, we equipped these bats with heart-rate and temperature transmitters. The bats were kept in captivity and video-taped. This preliminary data will help understanding the relationship between heart-rate, temperate and clustering prevalence. My fieldwork season is over but Sebas will stay until early September to operate more trials and continue this project in November-December, when we both go back for a new fieldwork season. For my Phd fieldwork in Panama, I use a wide variety of tools to measure, to transponder and to sample the bats I catch, often with help from fieldwork assistants or some colleagues. I use generally 7 tools, described here and shown on the photo below. 1. The first tool is a scale, used to measure the weight of the bat (placed in a soft clothed bag). This feature gives a good idea about the age of the bat or if it has eaten. For examplen, my species weighs around 10g and can come back from foraging weighing 3-4g more. 2. The second tool is a calliper, used to measure the forearm length. This feature is often used as an help for species determination. 3. The third and fourth tools are a transponder needle mounted on a transponder injector. The needle contains the transponder that will be quickly injected under the bat skin of the bat. This is a sensitive operation but I trained and I process quickly. The transponder - with an individual identification number - will be injected once and will last for the whole life of the bat. Once the transponder is inserted, I check the number with a hand transponder-reader. 4. To sample DNA, I use a biopsy wingpunch. This tool consists of a 3mm-diameter metal ring mounted on a plastic pole. The DNA is sampled on the wing membrane, the "wingpunch" is then stored in a small tube of ethanol. The sampling on the wing membrane is optimal because this body part contains a lot of DNA and the healing really quick (around 2 weeks). Another story starts after for exportation of the samples, extraction of the DNA and of course the analyses... Thanks to Hyuen-Ji Lee for the picture :).
PS: All catching and sampling procedures are realised with permissions from the Panamean authorities. Last week was pretty intense with three different meetings!
The first meeting was my PhD commitee with my PhD advisors. One year after the beginning of my PhD, this meeting is intended to talk about the progress, identify the weaknesses and discuss about the program for the following year. Principal advice (useful for me but every student in general) - don't neglect the reading of papers and books... With all the other tasks (fieldwork, logistics...), it can be easily set aside. The second meeting was a brain huddle - a sort of brainstorming. With colleagues from the Max Planck Institute for Ornithology, we discussed about the data from the automated balance systems I have installed in Panama. The discussions helped me to get interesting tips about the way to look at my data and extract the essential information. In the next weeks, I will try and move forward with these automated analyses To finish, the third meeting was about the tracking session that will occur in Spring 2013. This fieldwork session will combine tracking of Molossus molossus and Uroderma bilobatum to understand the social foraging of these two species. The meeting was intended to talk about the methods and logistics. A blogpost (at least) about that next Spring :). A year has passed since I have started my PhD.
A lot of my time and energy went into this fieldwork season (mid-March until end July) to catch and transponder some bat colonies of my model species - Molossus molossus - in the village of Gamboa in Panama. After numerous hours of wood cutting and video check, I managed to instal automated balances that are monitoring bat activity thanks to their transponders. A contact in Gamboa is sending me the data by e-mail on a weekly basis. And my current program for the weeks to come is to try and extract the best information from this great source of data. I am also reading and writing to move forward on my PhD introduction – in parallel to fieldwork organization for the session of November-December (6 weeks) and the big tracking session in Spring… Stay connected! A little article on PIT tags was published in June's STRI newsletter. My boss and I use this technology
to recognize marked bats using a hand-transponder reader and also to recognize bats when they crawl through the automated balances that I have installed in Gamboa. "How does one track the comings and goings of bats, birds, frogs and other animals? A rice-grain sized PIT tag injected under the skin makes it possible to identify individuals using a hand-held tag reader. Passive Integrated Transponder tags consist of a small glass capsule containing electromagnetic coils that act as a combined receiver/transmitter. When triggered by an interrogating signal, the antenna in the tag uses voltage generated by the signal to radiate an alternating magnetic field coded with a unique ID number. This technology was first developed in the 1940’s to distinguish friendly from enemy aircraft. The same concept lets you open a door by waving a card in front of a reader. Since the 1980’s PIT tags have been employed to monitor fish populations and to identify valuable zoo animals and pets. Radio Frequency Identification Technology in printed tags tracks goods in the global supply chain. Seven millimeter-long PIT tags cost a little less than $5.00 each." During last weeks, I focused on fieldwork and writing.
I have finally 5 automated balances installed and connected to direct power but I still have to solve technical problems and start analysing the data to see if the balance is acquiring the data required for the project. I still have one month to make sure balances are correctly working before coming back to Germany. In parallel, I have also invested a lot of effort to write the first chapter of my PhD. This wednesday I received a lot of feedback from the people of Rachel Page's lab. I still have a lot of work to do but I have now a clearer view about where I am going. As an extra, I will present next monday a small talk for kids of the school of Gamboa called "The secret life of bats" to do some public outreach about bats. Yann Originally created by two french bat researchers, Meriadeg and Sébastien, the "Chiroblog" is a french blog relaying news from the bat world. For several months, I have joined the editorial team. Resolution of year 2012 consists in publishing a monthly newsletter selecting the most relevant publications on bat research. A new function is now available with an automatic translation from french to english, spanish, german and many other languages!
Wishing all of you pleasant moments on the Chiroblog. After a long flight from Zurich (Switzerland), I finally arrived in Panama. For three weeks, I will stay in the village of Gamboa, closeby the Panama Canal and surrounded by the jungle. This is the place where I will come several times for my PhD fieldwork on Molossus molossus. Numerous colonies of the species can be found troughout the village. Furthermore, numerous facilities (housing...) are available through the Smithsonian Tropical Research Institute. Here are a few pictures for you to discover this great place. I will keep you posted about my naturalistic observations !
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