Nature-inspired flight

In a new issue of the journal Bioinspiration & Biomimntics, a special section is devoted to nature-inspired flight. There is an emphasis on MAVs of various sorts, but also purely animal flight papers have been included. The issue has been edited by two well-known figures in our field, David Lentink and Andy Biewener. The latter is handling most of our mansucripts submitted to JEB. The two editors write an introductory essay, following by the original papers. Have a look here. There will be reason to return to these papers.

Operation snow storm: lab meeting

During the lab meeting today (29 November 2010) the AFL-members that made it to the Ecology Building, in spite of the snow-storm, discussed the recent paper about “The effect of body size on the wing movements of pteropodid bats, with insights into thrust and lift production”. This paper, from the Brown University Group, reports on kinematic parameters studied in six species of bats. The paper concludes that “the ways that bats modulate their wing kinematics to produce thrust and lift over the course of a wing beat cycle are independent of body size”. How convenient if this proves to be true! The authors however thinks that small bats, such as Phyllostomids, may differ from the medium to large sized bats studied here. One reason put forward could be that small bats, using a leading edge vortex, are more insect-like in their use of aerodynamic mechanism, and therefore different from other bats. It will be interesting to find out of smaller species of bats differ in flight.

A new paper on bat flight has now been published by the Brown University group in the Journal of Experimental Biology (Hubel et al. 2010), where they report on the wake dynamics in a medium sized bat, Cynopterus brachyotis, when it is flying at intermediate speeds (5 and 6.7 m/s). The wake is very similar to that found for other bat species studied in Lund, which lend support for the notion of the generality of these results. Hence, it is very nice to see results of bat aerodynamics being confirmed by anther lab. Since papers of bat flight are still quite rare, this paper will be the focus of our next lab meeting, which will be Monday 11 October, 2010.

Melissa is back in the US

As the remaining AFL crue has noticed Melissa Bowlin has left Lund after 2 years here as Marie Curie postdoc fellow. It has been two years of intense work, including wind tunnel experiments, writing of book chapters, conferences and symposia. Melissa left with lots of data still to be analyzed and published, perhaps most notably about the effect of moult gaps on flight performance in passerine birds. Melissa has now taken up a new position as assistant professor at Dearborn, Detroit, where she is teaching animal physiology alongside her own research. We wish her all the success in her new position in the US, but also that we will remain in close contact in the future.

MAVs navigating without GPS

Engineers at MIT has built a MAV that is able to navigate inside a complicated environment, where GPS navigation is denied. The vehicle is perhaps mainly interesting for its navigations skills rather than it's flight performance. The MAV has a laser scanning the environment to build up an image about the surrounding topology. At the recent International Bat Research Conference in Prague, there were talks about using sonar systems similar to those of bats to navigate the environment. The real challenge will be to combine any of these navigation based systems with a MAV that uses flapping flight, and flies like a bat or an insect. A film showing the MAV flying indoors can be seen by clicking here. The accompanying paper is not very new, published in Science in late 2009.

Animal Flight Lab on Bat Conference, Prague

Members of the Animal Flight Lab are currently attending the 15^th International Bat Research Conference in Prague. This is the main outlet for bat science, being the biggest assemblage of bat scientists ever at 550 individuals. In the afternoon on Monday (23 August) we had the flight symposium, organised by Anders H and Sharon Swartz, Brown University. Members of both the Lund and Brown labs gave excellent presentations, showing how kinematics and PIV data could be used to get lots of information (Florian Muijres and Rhea von Busse). Other talks were on flight mechanical constraints on bat size (Ulla Lindhe Norberg), context-dependent flight speeds (Marc Holderied), energetics by Na-Bicarbonate isotope analysis (Christian Voigt), and muscle and tendon morphology in the wings (Sharon Swartz). In the evening, the whole group of speakers went in to Prague for a excellent dinner at a restaurant (Café du Paris, see picture). After dinner we strolled through central Prague and into the old city. Today (Tuesday, 24 August) we have enjoyed many more interesting talks, and soon we will attend the poster session, where Melanie Stuiver will present her poster on the bat robot (RoBat).

News on power curves

Summer is coming to an end and we have an autumn of activities to look forward to. As a starter, I would like to recommend a series of papers just out in the J Exp Biol, in which the mechanical power was measured in cockatiels. In three papers the researchers measured muscle work, compared muscle work with output from a aerodynamic model, and finally measure the flight metabolic rate to get conversion efficiency. The papers discuss all the difficulties and pitfalls, we are so well aware of, but they constitute a good and recent update on the subject. It is concluded that power consumption during flight must come from more than just the main flight muscles (Pectoralis major/supracoracoideus), otherwise the efficiency must be extremely low in the order of 10%, or so.

California Dreamin'

Today the great news reached us that Marta (Wolf) has received a prestigious postdoc stipend from the Swedish Research Council. This is an outgoing postdoc for Marta to work in Robert Dudley's lab, University of California, Berkeley. There, she will study the evolution of flight in insects, and we now look forward to hear reports from her research and Californian experience.

Congratulations Marta!

New paper on LEV

In a new paper by Tatjana Hubel and Ca Tropea published in J Exp Biol, the occurence of LEV in model wings is investigated. The wings are large, goose size, and the kinematics resemble that of a large bird as well. Still, these wings develop LEVs associated with a delayed stall. These results suggest that even relatively simple kinematics of forward flight in largish birds are potent in developing non-ignorable LEVs associated with unsteady aerodynamic effects. The authors also raise the question whether the quasi-steady approach to bird flight, as adopted in the most popular flight models, perhaps now should be reconsider. I anticipate we will need to discuss this in the near future.

New Lab Publication

It was recently demonstrated that shorebirds (godwits) fly non-stop between Alaska and New Zealand on their autumn migration - a flight that takes more than a week! Do we need to revise our current flight models as a result of these observations? How did such long flights evolve? These, and other questions are discussed in an "unsolved mystery" piece in the May issue of PLoS Biology: http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1000362

New lab publication

Two members of the AFL and their co-authors have written a paper titled, 'Grand Challenges in Migration Biology', which was published online in the journal Integrative and Comparative Biology today. The paper grew out of the symposium on Integrative Migration Biology that A.H. and M.S.B. attended in January.

The paper can be found on the 'advance access' portion of ICB's website, here: http://icb.oxfordjournals.org/cgi/reprint/icq013 .

DelFly makes it into the Lund Wind Tunnel

On Friday 9 April, last week, the dutch MAV experts B. W. van Oudheusden and Bart Remes from the TU Delft visited Lund and the Animal Flight Lab. The reason for their visit was discussion about Melanie Stuiver's MAV design. The dutch lab develops some famous MAVs, such as the DelFly, which is inspired by insect flyers such as dragonflies (and uses a clap-and-fling mechanism), and the Roboswift, which is inspired by the morphing wings of real swifts. As a proof of concept the DelFly was tested in the wind tunnel, with medium success. It turned out to be somewhat hard to control it's flight in the tunnel, but after some practice pilot Bart Remes could keep the fly stationary in the test section at a speed about 2 m/s.

Rhea gets FAZIT stipend

AFL member Rhea von Busse has received a FAZIT stipend, which is a foundation of the FAZ (Frankfurter Allgemeine Zeitung), which is one of the biggest, reputable German newspapers. They are mainly known to support Journalists in their career but they also support scientific research by giving stipends to doctoral and postdoctoral candidates. Rhea says "I didn’t even know that they provide PhD stipends, but one of the grant counselors at my University told me to apply there and don’t feel discouraged by their guidelines, which mostly address Journalists.". Rhea has collected all of her data to finnish her PhD thesis, and now "only" has to analyze those and write up some manuscript.

Congratulations to Rhea!

Bat ecology on SVT Play

Yesterday, monday 15 March, SVT sent a nature film following a group of Germans and US scientists working with bats on Barro Colorado, Panama. This rater small island holds 72 species of bats and one main question addressed by these biologists is: how can they co-exist in such a small area. The answer is multi-faceted, including roost sites, food type and flight/foraging altitude. We can see the biologists catching bats, filming them in infrared, recording their sounds and making experiments. Even if the film is narrated in Swedish (could be a good practice for those who are still learning swedish), the scientists themselves speak in english. I liked the film and strongly recommend it to everybody in AFL. It can bee seen at

http://svtplay.se/v/1926696/naturfilm/fladdermossens_paradis

Rabies in Swedish bats

Bats can get infected about a form of rabies (Lyssa virus), which rarely also can be transferred to other mammals, including Homo sapiens. Out of four fatal cases in Europe during the last few decades two have been bat researchers, so there is a small risk of handling wild bats in Europe. However, Sweden has thus far been without any reported cases of rabid bats. But new samples taken during 2009 in Skåne found antibodies against bat rabies in eight Daubenton's bats (Myotis daubentoni), according to a press release yesterday. These bats are non-migratory (at least we think so), and therefore they should have been in contact with actually sick bats at some stage. Hence, Sweden is no longer a rabies-free territory. But this is a fully expected result considering that rabies is found in our neighboring countries Denmark and Finland, and is common in Germany and Poland. Since many bats migrate to continental Europe it would have been strange if infected bats never turned up in Sweden. This new finding does not change any of the official recommendations for us working with bats, which include being vaccinated and wearing a glove when handling (such as ringing) bats. More information can be found at www.naturvardsverket.se/fladdermus .

To stay or to go?

Especially during a winter like this those birds that migrated south last autumn probably did a good choice in a Darwinian sense. In mild winters, however, those that decide to stay near their breeding areas may be at an advantage because they can select territories first and they don't have to pay the cost of migrating. Many bats have evolved the alternative strategy of hibernating, which means that they lower their body temperature almost to the ambient, and therefore they spend very little energy. But there is an energy cost and the fat they accumulate in the autumn must last until spring, when insects emerge again. In that sense they can be compared with bird migrants, but instead of converting fuel into distance, they migrate in time. In bats, there are species that do migrate, often in combination with hibernation at the winter destination, and we may think about how this strategy came to be? Here, I want to share some images from a recent winter bat count in the mine at Taberg, Småland. Six species were encountered, and here are pictures (lower) of Whiskered bat (Myotis mystacinus; the two small ones) and Brandt's bat (M. brandtii; the two larger ones on the right), and the picture on top shows a Natterer's bat (M. nattereri), which is quite a rare species in Sweden.

Party in Animal Flight Lab

Congratulations to Per Henningsson on his thesis defense on 29 January. With opponent Bret Tobalske we witnessed a very interesting discussion about bird flight, and swift flight in particular. Now we are looking forward to a great party tonight, and wish Dr Per a successful postdoc and career! The red-flanked blue tail Tarsiger cyanurus shown her to the right is Per's latest acquisition on his Swedish list. Congratulations also to that!

New thesis: flight of swifts

On Friday 29th January 2010, Per Henningsson is defending his thesis on "fluid dynamics, flight performance and flight behavior of common swifts". The defense takes place in the Blue lecture hall at 10:00, with Prof. Bret Tobalske as faculty opponent. On the day before, you can enjoy an extra CAnMove mini-sympoium on the animal flight, starting at 14:00 in the seminar room "Tanken", in which Bret Tobalske will talk on his fascinating research on hummingbird flight. That the swift is a remarkable bird is perhaps not new to most of us, and Per is now getting some well deserved media attention for his spectacular PhD thesis. See e.g. http://www.gp.se/nyheter/sverige/1.296297-flygexpertens-hemlighet-avslojad ).

Looking forward to a great week

As for our next lab meeting on Monday 25th January (2010) we will join forces with the Svensson lab. Time is our usual at 09:00, and location is also the usual (Argumentet). We will discuss some relevant insect flight papers that Sophia will distribute.

It should also be mentioned that Melissa Bowlin has accepted a faculty position at the University of Michigan Dearborn, and we wish her all the best of luck there. But before that Melissa will be with us until August to finish lots of interesting projects.

Next week is going to be eventful in other respects as well. On Thursday at 14:00 we will have a mini symposium on the aerodynamics of flight. Main speaker is Dr. Bret Tobalske (see image), University of Montana, who will talk on hummingbird flight, with a few other talks from AFL reps. Bret Tobalske is here also to act as faculty opponent on Per Henningsson's thesis defense, taking place on Friday 29 January at 10:00, Blue Lecture Hall.

Animal flight lab in Seattle

Greetings from Seattle! The Space Needle and the mountains looked on as two members of the flight lab, Anders and Melissa, gave talks at this year's SICB meeting. Melissa (who is currently talking about herself in third person) introduced the Integrative Migration Biology symposium she had organized, and Anders spoke about mixing theory and wind tunnels to increase our understanding of animal migration.

The symposium went very well, down to a last-minute replacement talk by Ken Lohmann for Tom Kunz, who was ill and couldn't attend the conference. A Science reporter was at the event speaking to several of the speakers, and we were approached about potentially writing a book (something that, if it happens, won't be happening anytime soon!).

There were many interesting flight talks, but since many of them were at the same time as the migration session, I didn't get to see them. Hopefully Anders did and he can fill you all in on all of the exciting research going on in the US. I personally got to meet up with old lab-mates and friends, and generally enjoyed the area (including some wonderfully fresh seafood!).