New research on bats

During this week two interesting papers on bat biology have been published. First, McGuire et al (J. Anim. Ecol. doi: 10.1111/j.1365-2656.2011.01012.x) reports on radio tracked silver-haired bats at Long Point Bird Observatory, Ontario, Canada, Radio tagged birds were tracked using 5 towers with antennas. Most bats stopped over for 1-2 days before continuing migration, while some bats stayed for up to two weeks. Another paper, by Elemans et al (Science, Vol. 333: 1885-1888) reports about ultra-fast laryngeal muscles, which can produce echolocation calls at rates beyond 160 calls per second. Bats use such fast repetition rates during their final approach to a prey, calls known as feeding buzzes that are heard in a bat detector.

New Animal FLight Lab website

The Animal Flight Lab at Lund University proudly presents its new website. We have updated the content, both when it comes to members of the lab, current projects and new publications. There have been some changes in recent time. Marco Klein Heerenbrink has started as PhD-student, and will explore aerodynamics of gliding flight further anyone else before. Sophia Engel, who has been a CAnMove funded postdoc for two years, left last Sunday for southern Germany. During her time here, Sophia has made a number of wind tunnel experiments on insects and some very extensive field experiments on flight performance in damselflies. There are now plenty of data to analyze and write up. At todays lab meeting it was decided that, in addition to the newest research papers, we will also start reading the 'classics' in the field of animal flight.

Textbook about bats

It is time to activate this blog again, a semester and a new lab meetings ahead. We, the Animal Flight Lab at Lund University, will have weekly lab meetings on Tuesday mornings at 09:00, where we discuss a recent paper and other lab businesses. We look forward to a very active autumn, and we especially welcome Christoffer back from a paternal leave! It is a pleasure to note that there is a brand new edition of John Altringham's book "Bats: from evolution to conservation" (Oxford), where the flight section has been updated to include some Lund results on bat wakes. We appreciate this since the current view on bat wakes has changed quite dramatically in recent years due to those experiments, which have also been confirmed by experiments at Brown University. So, we finally made it into the textbook lore!

Please also note that the lab is looking for a new PhD student (see advertisement at the links below, in Swedish and English, respectively).

http://www.lu.se/o.o.i.s?id=22598&Dnr=419462&Type=S

http://www.lunduniversity.lu.se/o.o.i.s?id=24914&Dnr=419462&Type=EU

New PhD thesis from Animal Flight Lab

Florian Muijres has received his thesis from the printer and is busy distributing them. The thesis contains seven different studies about aerodynamic performance in bats and birds. Two papers describe a high lift mechanism - Leading Edge Vortex - used by bats and pied flycatchers when flying slowly. This vortex enhances lift by 40% or more in these vertebrates, and before Florians work it was thought to be a typical insect mechanism. In other papers time-resolved PIV is used to work out aerodynamic efficiency of bats and birds, and to evaluate an adaptation of the classic actuator concept of flapping flight. Florian is to be congratulated to marvelous thesis, which is not only interesting on the inside but also beautiful on the outside. The public defense will take place on 28 April at 10:00 am, in the Blue Lecture Hall, Ecology Building, Lund. As faculty opponent we are very glad to welcome Professor Tom Daniel, University of Washington, Seattle.

New paper about bat aerodynamics from Animal Flight Lab

A new paper, entitled Comparative aerodynamic performance of flapping flight in two bat species using time-resolved wake visualization from the lab was published today in the Journal of the Royal Society Interface, in which Florian Muijres and co-workers compare two species of bat with regard to their aerodynamic performance. Florian has developed very detailed methods for analyzing the wake properties, as recorded by time-resolved stereo PIV in the Lund University wind tunnel. The two species being compared, Glossophaga soricina and Leptopnycteris yerbabuenae, differ with a factor of 2 in mass and in some ecological respects. The Leptonycteris is a migrant while the Glossophaga is a resident, while they are both fruigivores that eat/drink nectar from plants using hovering flight. A measure of flight economics, the maximum lift to drag, was similar between the species, but it occurred at a higher speed in the larger species. This could reflect different performance optima between the two species associated with requirements for slow flight in Glossophaga and cruising/migratory flight in Leptonycteris. The wake geometry showed the typical bat features in both species, including reversed vortex loops at the transition between up-/downstroke and vortices shed from the wing roots.

Animal Flight Research Highlighted in Research Council Annual Report

In the current "Annual Report for 2010" from the Swedish Research Council (VR), our research on animal flight was selected to illustrate "basic research of the highest quality", which is an investment in the future. It's very nice to be appreciated in this way, I think, by our main funding body and we should see that as a token of achieved quality and visibility. There is also some accompanying text on VR:s website, with answers to some questions about the research. The picture on the left was taken earlier this winter, when AH was performing some critical experiments.

Rhea gets PhD

On last Friday our group member Rhea von Busse passed her oral examination for a PhD at the Humboldt University, Berlin. Dr Busses thesis is about "The trinity of energy conservation: kinematics, aerodynamics and energetics of the lesser long-nosed bat (Leptonycteris yerbabuenae)", including chapters on kinematcs, aerodynamics (wakes), a comparison between kinematics and wakes, and an investigation about the flight metabolic rate. This thesis is the result of the collaboration between AFL and York Winter. The discussions leading up to this collaboration were initiated some 10 years ago, when AH visited the Max Planck Institute at Seewiesen to give a talk about the wind tunnel studies on birds that were underway. Then Rhea came with the first batch of Glossophaga soricinas used for our first studies (and Rheas master thesis). We congratulate Rhea to this magnificent achievement and wish her the best of luck with her new studies on bats in the Brown University bat biology group.