onsdag 22 december 2010
During the Häckeberga CanMove meeting in October, Staffan, Helena, Karin and Lasse started to discuss the possibility to use Daphnia pulex as an additional organism in CanMove´s search for “the migratory gene”. This organism is easily cultivated, produces a lot of cloned kids and, which is important, its genome is known. Later, when inspired by Steve Repperts talk on the Monarch butterflies during Miriam´s symposium on “Genetics of migration”, we decided to make this new initiative take real action. Our first steps have been to grow the organism and make some background search for information. So, in order to inform you all about this initiative, we hereby enclose a Christmas card from the lab. where the creatures are now reproducing and wishing us all a Merry Christmas and a Fruitful New year!
torsdag 9 december 2010
tisdag 7 december 2010
We were indeed honoured by the number of participants, and excited to literally welcome participants from all over the world - thanks to you all having made this long trip to participate. It was great having had so many enthusiastic scientists - all working on one or the other aspect of the genetics of migration - here.
The backbone of the meeting was formed by six talks, presenting state-of-the-art research focussing on different aspects, covering a diverse range of taxa, and introducing methodological approaches that have recently emerged.
Steven Reppert from the University of Massachusetts shared insight into genomic, genetic and epigenetic approaches to monarch butterfly migration his lively lab is currently working on. Michael Banks from Oregon State University told us how genomics could help to elucidate spatiotemporal aspects of pacific salmon migration.
Within the field of migration, research on migratory birds has probably the longest tradition, and the talks of Martin Schaefer from Freiburg University and Staffan Bensch from Lund University focussed on microevolutionary processes and patterns of genetic and phenotypic variation along migratory divides in two migratory songbird species. Migratory divides as well as hybrid zones are great natural laboratories to study evolutionary processes and speciation, and the talks given by Anna Qvarnström and Jochen Wolf, both from Uppsala University, focussed on what we can learn from a Flycatcher hybrid zone, and how a genomic approach help us to incipient speciation in Carrion and Hooded crows.
Besides excellent talks, the highly interactive meeting included lively poster session and general discussions, sharing information and experience on the changes due to revolutionary technological achievements in this field. We closed the symposium with a plenary discussion evaluating methodological approaches to be focused upon, and critically assess possibilities and pitfalls thereof. The discussion also highlighted both importance and challenge of most accurately defining and controlling the target phenotype in focus, as well as including environmental variables in experimental design and analyses.
Discussion and plans for future projects, ideas for further development and collaboration continued over dinner – and will most certainly continue long thereafter.
måndag 22 november 2010
One consequence of animal movement and dispersal is gene flow between populations. Gene flow is generally thought to limit local adaptation and population divergence, since local selection is opposed by the homogeneising effects of gene flow. In spite of this, we often find that populations differ in morphological, physiological and behavioural traits, and one way why such population divergence can be achieved is through adaptive phenotypic plasticity. In terms of behavioural traits, it is increasingly being recognized that learning can be important, particularly when it comes to population divergence of mate preferences.
We have studied the effects of learning on the development of female mate preferences in a charismatic insect species: the banded demoiselle (Calopteryx splendens). Males of different species in these calopotergid damselflies are well-known for their enigmatic melanized wing patches, which serve multiple ecological functions, including mate recognition and species recognition for females.
Recently, we have showed that female mate preferences are not entirely genetic, but are partly learned, and develops in females as a result of physical pre-mating interactions and/or during mating with males. The result of this learning is that populations that are even close to each other and hence experience a lot of gene flow in between them, can diverge substantially in mate preferences, due to such learning. It is interesting that even these small insects have such advanced cognitive ability so that they can actually learn whom to mate with, and who is the wrong mate! Our paper has recently been published in the journal Evolution, where we also contributed with the cover photo of a male banded demoiselle aggressively defending his valuable territory (a water lilly). Our article was also covered by the popular science site and media outlet Science Daily.
Below is the link to the article and the abstract:
A ROLE FOR LEARNING IN POPULATION DIVERGENCE OF MATE PREFERENCES
Erik I. Svensson, Fabrice Eroukhmanoff, Kristina Karlsson, Anna Runemark & Anders Brodin
Learning and other forms of phenotypic plasticity have been suggested to enhance population divergence. Mate preferences can develop by learning, and species recognition might not be entirely genetic. We present data on female mate preferences of the banded demoiselle (Calopteryx splendens) that suggest a role for learning in population divergence and species recognition. Populations of this species are either allopatric or sympatric with a phenotypically similar congener (C. virgo). These two species differ mainly in the amount of wing melanization in males, and wing patches thus mediate sexual isolation. In sympatry, sexually experienced females discriminate against large melanin wing patches in heterospecific males. In contrast, in allopatric populations within the same geographic region, females show positive (“open-ended”) preferences for such large wing patches. Virgin C. splendens females do not discriminate against heterospecific males. Moreover, physical exposure experiments of such virgin females to con- or hetero-specific males significantly influences their subsequent mate preferences. Species recognition is thus not entirely genetic and it is partly influenced by interactions with mates. Learning causes pronounced population divergence in mate preferences between these weakly genetically differentiated populations, and results in a highly divergent pattern of species recognition at a small geographic scale.
måndag 15 november 2010
A major problem when studying behavior and migration of small organisms is that many questions, easily addressed for larger animals such as birds or fish, cannot be asked when it comes to animals of millimeter size, since tracking devices are too heavy to allow for the organism to act naturally. Recent advances in nanotechnology have, however, made it possible to individually track small animals. In a paper recently published in PloS One (Lard et al. 2010 PLoS ONE 5(10): e13516. doi:10.1371/journal.pone.0013516) we report on a novel approach to track movements and migratory behavior of millimeter sized aquatic animals, using nanometer sized fluorescent probes (quantum dots). Compared to previously used methods to label small animals, the nano-labeling method presented here offers considerable improvements. The method, developed in close cooperation between biologists, chemists and physicists, offers new opportunities to routinely study zooplankton responses to e.g. light, food and predation, i.e. opening up for advancements within research areas such as diel vertical/horizontal migration, partial migration and other differences in intra- and interspecific movements and migration. So, although our results are preliminary and the method still rough, CanMove is advancing the knowledge and opportunities also with respect to small organisms!
torsdag 4 november 2010
Two examples of the influence of ecological barriers on migratory strategies have been shown: the Eleonora’s falcon breeds in Mediterranean islands and reach the wintering grounds, located in Madagascar, in a 9’000 km journey. These birds migrate also during night, especially when crossing the Sahara desert, in order to overcome this ecological barrier as soon as possible. Besides this, Eleonora’s falcons are able to cross large water bodies like the Indian Ocean, flying non-stop also for 1’500 km and changing route accordng to weather conditions. Conversely, the Short-toed eagle is a broadwing raptor less adapted to flapping flight and therefore unable to cross large stretches of sea. The migratory strategies of the populations breeding in peninsular Italy are deeply influenced by the geography of the Mediterranean basin.
You can follow the journey of two eagles tagged with satellite transmitter from this website, where the maps are constantly updated.
Some papers concerning these researches can be downloaded from this website.
onsdag 3 november 2010
A collaborative team of researchers from the Danish Technical University and CAnMove at Lund University, led by Dr. Christian Skov, recently investigated this question in a species of partially migratory freshwater fish, the common bream (reported in Proc. R. Soc. B.). Common bream stay in lake habitats over the summer and part of the population migration into streams over the winter. In the lakes during the summer the risk of predation is high, but the rewards are also high (high food availablity). During the winter predation risk decreases as predators become less active and eat less, but food availability also decreases, reducing the benefit of staying in the lake. If the risk/reward ratio for residency in the lake differs over the winter between individuals (when the rewards for staying are relatively low), this may lead to partial migration. One way in which individuals differ that would affect this risk/reward ratio is in their vulnerability to predation. Hence, all else being equal, one would predict that fish that are more susceptible to predators would be more likely to migrate, and that differences in vulnerability between individuals might explain why some migrate and some stay resident.
To test this prediction Christian Skov and his team were able to assign >450 individual bream from 2 lakes in Denmark with a 'predation vulnerability' score, which they calculated by sampling large numbers of piscivorous predators (pike) from each lake. The vulnerability score was calculated by estimating what proportion of predatory pike in a lake could eat each specific bream (as pike are gape limited predators). The bream were individually tagged and released and their migratory behaviour monitored over the winter. As predicted, fish with a high vulnerability score showed a much stronger propensity to migrate, migrated earlier and stayed for longer in the streams. This research is important as it suggests a powerful role for predation in shaping patterns of migration.
So it seems for bream the question of 'should I stay or should I go?' depends upon an individual's vulnerability to predation. For smaller, more vulnerable fish, if they go there will be trouble (after all migration is a costly and risky business), but if they stay there may be double...
Read the full article here: http://rspb.royalsocietypublishing.org/content/early/2010/10/26/rspb.2010.2035.full
Here is the full reference:
Skov C, Baktoft H, Brodersen J, Bronmark C, Chapman BB, Hanson L-A, Nilsson PA. 2010. Sizing up your enemy: Individual predation vulnerability predicts migratory probability. Proc. R. Soc. B. (in press)
måndag 1 november 2010
Bird populations are doing gradually better the further away they are from the hottest part of their distribution range, or...
... Success in the north, trouble in the south
Climate change is affecting our fauna in various ways, by influencing distribution range, population size, and migration and breeding phenology. For example, recent studies have shown that European bird species living in a colder climate (that is, generally more northern bird species), are doing relatively poorly compared to species used to a warmer climate (more southern species).
As far as distribution goes, shifts at the poleward limit of the distributional range, or at the upper edge of the altitudinal range, have been documented for many taxa. But beyond changes at range limits, more subtle changes within the ranges of species are also likely, and might have important ecological and evolutionary consequences.
In a French–Dutch–Swedish joint effort we studied how the different populations of 62 common European bird species have developed over 20 years (1989–2008), as recorded in national bird monitoring schemes. France and Sweden were each divided into three equally sized latitudinal belts, and the Netherlands was considered a belt of its own. The following independent factors were used when trying to explain recent population size changes within these latitudinal belts: the thermal distance (in °C) to the thermal maximum of their European distribution (how far the birds are from the warmest part of their range), habitat preference, habitat specialization, body mass, latitude and migration distance.
For the 62 species considered, we found a gradual and linear significant increase in long-term population growth rate along the thermal range, when moving towards a species coolest range limit. Accordingly, the bird populations were doing better and better the further away they were from their thermal maximum (put in another way, the closer they were to the coolest part of their range). This effect was detected beyond other effects expected to affect population growth rates, such as the decline of farmland birds and habitat specialists.
We failed to highlight that long-distance migrants were more prone to decline, as has been shown in several other studies, probably because the studied set of species was restricted, excluding some Afro-Palaearctic migrants that do not occur in all the three studied countries. Also, recent declines in long-distance migrants are most severe in seasonal habitats in Western Europe, whereas we studied a broader array of habitats and countries.
Thus, beyond previously known effects on population dynamics near range limits, we revealed that population dynamics were not randomly distributed within species range, suggesting that European breeding birds are influenced by climate warming, and are experiencing demographic disequilibrium, along their whole thermal range.
Jiguet, F., Devictor, V., Ottvall, R., van Turnhout, C., van der Jeugt, H. & Lindström, Å. 2010. Bird population trends are linearly affected by climate change along species thermal ranges. – Proc. R. Soc. Lond. B 277: 3601–3608. Read the full article HERE.
// Åke Lindström
tisdag 19 oktober 2010
Winter is approaching fast, and what could be better then than to try to remember the past beatiful summer for as long as possible?Varm summers means field work with insects, at least for some of us. This was also the case for myself, CAnMove postdoc Sophia Engel and a number of other students and postdocs working with field studies of calopterygid damselflies. Here is a nice movie about CAnMove-related field work from Lund University's Youtube-channel. This movie contains an interview with Sophia and myself, where we explain what kind of experiments we did, and why. Unfortunately, this movie is in Swedish, not English, but at least you can enjoy the pictures!
Basically, we have quantified flight speeds of individually marked damselflies of two species (Calopteryx virgo and C. splendens), and we relate this performance-trait to wing morphology (shape), longevity in the field and mating success (sexual selection). A key player in this system is an enigmatic avian predator which kills these insects: The white wagtail (Motacilla alba), which also appears in the movie. The ornithologists among you readers will hopefully also realise how fascinating this insect system actually is, since it obviously also involves a bird! A key goal of ours is to link morphology to performance and fitness, and combine flight speed estimates with data on morphology and fitness. Such studies are rarely possible to perform, particularly not in natural populations of insects, so we are quite excited about the results that will hopefully come out from this work.
If the movie above does not work, you could follow this link instead. Enjoy! And go back and watch this movie whenever you miss the summer...
tisdag 28 september 2010
Today the first group of enthusiastic and brave CAnMovians started the series of brainstorm events to discuss development of research areas within CAnMove for the coming years. The task was to highlight the most interesting questions and needs to fulfill the identified research goals. The first event covered an at first glance odd combination of research areas which included residency, partial migration and nanobiology. Lars-Anders Hansson chaired the discussions which turned out to be very creative and the group formulated a suggested plan including infrastructure investments, new collaborations and manuscript ideas.
The next event is Orientation & Navigation, Migration Patterns (chair: Susanne Åkesson) - 30/9 at 13:30 - 15:30h in Communis.
All CAnMovians are Very Welcome to take part in the brainstorming events and to be involved in formulating the new directions of CAnMove research!
måndag 27 september 2010
By Keith Larson
On 18 May we departed from Lund University, southern Sweden, the destination, 61˚ north latitude along the Baltic coast of Sweden. Our goal was to trap willow warblers along several transects traversing a secondary contact zone for two subspecies spanning the center of the country from east to west. On this trip we would drive over 5000 km from the Baltic Sea in the east to the mountains on the border of Norway to the west and back trapping almost 400 birds at 30 sites in seven weeks!
The first transect was along the Baltic coast from Söderhamn to Umeå with trapping occurring at sites previously sampled between 1996 and 2004. From the first day we set our nets we noticed that our target species, despite being the most abundant species in Scandinavia, was less abundant than during our previous two trapping seasons. This year to reach our site sample size we had to work many more hours and trapped over larger areas. It had been a long cold winter and signs of summer were a long way off!
Most days started before sunrise with breakfast, packing the car, and driving forest roads all day long, sometimes until after sunset. Along the roads we were searching for patches of birch, the preferred habitat for willow warblers. Armed with an mp3 player and speaker we intruded into the territory of each male willow warbler we could locate. The song blasting from the speaker typically elicited an aggressive response from the owner. With good luck and a properly placed net the result was a bird in the net.
The first willow warbler in the net was a great moment each day. We collected biometrics, a little blood for genetic analysis, and a couple of feathers for stable isotope analysis. The bird was released with a ring and maybe now marked will be recaptured during migration somewhere between Sweden and Africa!
The habitats varied tremendously from site to site. The perfect patch is a dense stand of birch with low branches or an understory that will attract singing males from the canopy. We have learned that there is a distinctive phenology in behavior and differences in individual responses to intruders within territories that dictates how to use the playback system. Some birds only give you one chance to catch them. If they bounce out of the net or fly low and you have the net set the wrong way you might never catch them.
The second transect crossed from the Baltic coast to the mountains of Lappland. As we progressed to the northwest, the stands of birch increased in density as did the number of willow warblers. Here we were fortunate to capture two willow warblers ringed elsewhere, the first on migration in Sweden during the previous fall and the second in Poland. By the time we had reached the end of the transect on the border of Norway near Hemavan it was early June. The long winter still had its grip on the land as the lakes where still frozen, the birch just beginning to bud, and an occasional snow shower to remind us of its presence.
The third transect followed the Inlandsvägen or inland highway from Storumån (famous for its skiers, arm wrestlers, and the Wildman) to Mora (home of the famous Vasaloppet ski competition). Here we trapped often in vast areas of managed forest that required lots of patience and persistence to trap our sample size each day. As winter finally turned to spring the onslaught of mosquitoes arrived! Fortunately we had head nets and jungle juice to make our work tolerable; drive, find patch of birch, listen for willow warbler, use playback and mist-net to catch willow warbler, collect measurements and tissues, release bird, and repeat – 15 times each day!
The final transect was from Idre north to Lake Anjan through the fjäll or mountains along the border of Norway. Here we traversed the contact zone from south to north. The scenery was fantastic and with vast regions of birch forest the trapping improved each day as we moved north out of the managed forests. Despite the large amounts of high quality habitat, we still had the impression that the density of birds was much lower than the previous two years. As we trapped our last birds of the season near Vålådalen, we wondered how such a different year might affect the structure of the contact zone.
Willow warbler field crew: Max Lundberg, John Boss, Miriam Liedvogel, Sieglinde Kundisch, and Keith Larson
måndag 20 september 2010
The aim of the symposium Genetics of Migration is to discuss the state of the art and identify future directions and methodological approaches, as well as providing an opportunity to interact with scope for future collaborations between different institutions.
The symposium will be held in the Ecology Building on 6th December 2010 and we very much welcome all people fascinated in the field of migratory genetics and all CAnMove members to participate. The programme will be centred on a backbone of six talks by key figures in the field presenting case studies across a variety of taxa. The preliminary programme can be found here. We will close the symposium with a plenary discussion to synthesise future directions, methodological approaches, and assess possibilities and pitfalls thereof.
We particularly encourage Ph.D. students to present and discuss their work with a poster presentation - there will be ample opportunity for interaction and general discussion with all participants.
Registration: Attendance of the symposium is free, if you want to attend, please register here. The deadline for applications is October 22nd.
Further information can be found on the CAnMove page "Conference and meetings", this page will be regularly updated.
We are looking forward to seeing you all at the symposium, welcome!
Miriam, Susanne and Staffan
måndag 13 september 2010
Last week we held a CAnMove symposium in 'The Ecology & Evolution of Partial Migration' at Lund University. We had 19 international speakers, including 4 CAnMovians, who presented theoretical and empirical research into partial migration in a diverse range of taxa, including neotropical birds, salmonid fish and ungulates. Partial migration, where just a fraction of a population migrates, is thought to be extremely widespread in nature. As technology advances and our knowledge of animal movement patterns increases, the prevalence of partial migration amongst migratory species becomes even more striking. Some of the highlights of the meeting included Mark Hebblewhite's (University of Montana) plenary talk about partial migration in ungulates. His group has shown that human activities have altered the cost/benefit balance of the resident strategy by reducing predation risk from wolves in areas with human settlements. We also had some illuminating theory talks by Per Lundberg and Anders Hedenstrom (Lund University), Allison Shaw (Princeton University), and our second plenary speaker, Hanna Kokko (Australian National University). Hanna gave an excellent introduction to the theory of partial migration, and showed that behaviour that is optimal for the individual is not always optimal when scaled to a population level.
Other highlights included Christian Skov (Danish Technical University), whose work highlights the importance of predation as a factor influencing conditional migratory behaviour in multiple populations of freshwater fish, bream. Courtney Conway (University of Arizona) also took a cross-population approach to test hypotheses of partial migration in burrowing owls in North America, and Alice Boyle (University of Western Ontario) presented a fascinating series of research projects which investigated the 'limited foraging opportunity' hypothesis both a a species- and community-level in neotropical birds.
All in all it was an informative and fun symposium, with a diversity of research questions in the area of partial migration, including the role of culture and learning, animal personality, and parent-offspring conflict in partial migration, which really highlights the breadth of activity in this resurgent field. We ended with discussions and a CAnMove barbecue. Many of the participants took advantage of juggling therapy from Marcus Ljungqvist to wind down from the symposium. Was he successful at teaching juggling to scientists? Well, at least partially ...
We will now begin work on a thematic edition of Oikos on the 'Ecology & Evolution of Partial Migration' which will include some of the exciting research we heard about at the symposium. Watch this space for more details!
tisdag 7 september 2010
Please, do not forget to sign up for the RIN11 conference!
The Royal Institute of Navigation will be holding the Seventh International Conference on how animals navigate (RIN11 Orientation & Navigation Birds, Humans & Other Animals) at Whiteknights Campus, Reading University, UK from midday Wednesday 6April until midday Saturday 9 April 2011.
Abstracts should be submitted to email@example.com by 15 September 2010. Notification of provisional acceptance will be given by 30 October 2010.
For more information on conference, please, see news section on CAnMove home page.
torsdag 26 augusti 2010
The 15th International Bat Research Conference, held in Prague 23-27 August, is coming to an end. CAnMove has been represented by four persons, all of who have made presentations. The main activity was on Monday (23 August), when we participated in the flight symposium, organised by Anders Hedenström (CAnMove) and Sharon Swartz (Brown University). Highlights today have mainly been the “Movement” symposium with presentations about bat migration in North America and Europe using stable isotope analysis. Ron Larkin, USA, presented echoes from goal tracking radar studies that likely represent migrating bats, while others presentations were about the use of satellite telemetry and GPS loggers on tropical fruit bats. There have also been some talks about the emerging field of bat orientation. The conference has given lots of ideas and inspiration to develop the research on bat migration at Lund. The image shows the speakers at the bat flight symposium, during the post-symposium dinner at Café du Paris in Prague city.
fredag 2 juli 2010
Post-doc programmet inom CAnMove har varit väldigt framgångsrikt och det finns nu ekonomiskt utrymme att utlysa ytterligare två (2) stipendier om vardera max 24 månader. Finansieringen kommer att följa den modell vi tidigare beslutat d.v.s. 18 månader bekostas från CAnMove och sedan finns möjlighet för den handledande PI´n att förlänga med ytterligare 6 månader (kostnad 21 200/månad). Om PI´n inte anser sig klara detta avbryts stipendiet efter 18 månader.
Om du är intresserad av att söka medel för en stipendiat kan du skicka in en kort ansökan (max 1 sida på engelska) som 1) Översiktligt beskriver det tänkta projektet; 2) visar att det tänkta projektet utgör en viktig del av CAnMove (är du osäker på vad som menas med detta så läs ursprungsansökan); 3) Om projektet handleds av flera PI´s inom CAnMove är detta en merit.
Skicka ansökan till koordinatorn (Susanne Åkesson, firstname.lastname@example.org) senast 15 September 2010. Utvärdering och rankning av ansökningarna kommer att göras av vår scientific advisory board (SAB). Beslut tas av Styrgruppen.
onsdag 30 juni 2010
Organisms that are harvested show some of the fastest trait changes observed in wild populations. Anthropogenic pollution has been also shown to increase the rate of evolutionary change in organisms in their natural environment. These rapid phenotypic shifts can have severe implications for management and conservation.
The theme of the course is human-induced evolution and will cover topics on contemporary evolution induced by exploitation, in novel environments, and caused by habitat modification and pollution. Contemporary evolution has been defined as evolutionary change observable over less than a few centuries. This course will include topics on evolutionary change in both terrestrial and aquatic environments.
Dates: 4-9 October 2010
Intended for: MSc, PhD students, researchers
Application deadline: 20 August 2010
For course information: http://www.bio.uib.no/evofish/pages/NMA2010/NMA2010.php
//A course that might be of interest to CAnMovers,
fredag 28 maj 2010
onsdag 5 maj 2010
In a cooperative CanMove project we used long-term databases on fluctuations in regional bird abundances as well as on limnological monitoring to study interactions between migrating waterfowl and stop-over lake ecosystems quality. We show that despite the large amount of migratory waterfowl, our study site L. Krankesjön, was not negatively affected by the waterfowl which removed less than 3% of the macrophyte biomass per year. Moreover, we show that most waterfowl species occured in lower abundances during periods with low density of macrophytes, than when submersed macrophytes flourished and the water was clear. This pattern was not affected by regional fluctuations in abundances. Hence, our study suggest that some migratory waterfowl taxa select stop-over lakes based on stop-over habitat quality, suggesting that migratory routes are not fixed but instead adjusted over time. If you are interested in reading the whole paper go to: http://www.limnol.lu.se/limnologen/publikationer/834.pdf
fredag 30 april 2010
In an interesting paper published online recently in Proceedings of the Royal Society B (Boyle et al 2010: see link below), Dr. Alice Boyle and co-workers present research into the effect of storms upon migration in tropical birds. Many animals, including birds, bats and insects, migrate up and down elevational gradients, from the lowlands to higher ground in mountainous regions of tropical forest. This is known as altitudinal migration, and the factors that drive animals to migrate in this fashion remain obscure. One idea, proposed forty years ago by Alexander Skutch, is that tropical storms could force tropical birds to migrate downhill. In this paper, Dr. Boyle and her co-workers test this idea, and also suggest a mechanism. They propose that one explanation for these patterns may be that storms reduce the time a bird can spend finding food at higher altitudes more than at lower altitudes, and that this reduction in foraging time may pose a very real risk of starvation.
Dr. Boyle tested these hypotheses with a species of partially migratory tropical bird, the White-ruffed manakin. White-ruffed manakins are small fruit-eating birds that breed in the wet, mountainous forests of Central America. After the breeding season some birds migrate downhill to lower altitudes whilst some remain at higher altitudes. Dr. Boyle found that capture rates at higher elevation decrease during storms and increase at lower altitudes, which suggests that storms do play a role in altitudinal migration in this species. Interestingly, at high altitudes before storms there is a bias towards males, and after storms a bias towards females, which may be linked to differences in body size between sexes (males are around 15% smaller). By collecting blood samples from birds and analyzing physiological measures of body condition, Dr. Boyle also found support for her ‘limited foraging opportunities’ hypothesis: rainfall was associated with plasma coricosterone levels, fat stores, plasma metabolites and haematocrit. These results suggest that weather-related risks for species requiring high food intakes can explain the altitudinal migrations of tropical animals. This is an important advance in our understanding of animal migration in the tropics, which may be important in conservation efforts. Furthermore, this work suggests that climate change may have significant impacts upon migratory birds in the tropics, as global warming is predicted to alter the severity and timing of rainfall events in tropical regions of the world.
Here is the link to the full paper:
torsdag 22 april 2010
Three members of CAnMove (Melissa Bowlin, Susanne Åkesson, and Anders Hedenström) are among the authors of a review recently published online by the journal Integrative and Comparative Biology. The paper, titled, ‘Grand Challenges in Migration Biology’, advocates the use of integrative research to address the big questions in the field of migration biology. It grew out of a symposium titled, ‘Integrative Migration Biology,’ organized by Melissa Bowlin, Isabelle-Anne Bisson, and Martin Wikelski at the annual Society for Integrative and Comparative Biology meeting in Seattle last January.
In the paper, Bowlin et al. argue that the best way to meet the ‘grand challenges’ of migration biology is to perform multidisciplinary research that includes multiple species and clades as well as the entire annual cycle of organisms. They also stress the importance of a strong theoretical foundation and the need to study migrants both in the laboratory and out in the field. The paper concludes by highlighting the data the authors believe will prove to be vital for conservation efforts.
‘Grand Challenges in Migration Biology’ can be found on the ‘advance access’ section of ICB’s website, here: http://icb.oxfordjournals.org/papbyrecent.dtl .
Photo: Arne Hegemann
torsdag 15 april 2010
söndag 4 april 2010
In temperate regions bats survive the winter either by hibernation (the typical bat strategy) or by migration south combined with hibernation in the wintering area. The fuel for hibernation (and migration) is fat, which is consumed at a slow rate throughout the winter. About now (March/April) is the time to wake up for hibernators, when they are running low on fat loads and they have to find food to survive. It is not uncommon to see bats flying around during daytime at the time of emergence from hibernacula. On good Friday (2nd April) the Hedenström-Åkesson family had been bird watching around Voms ängar and Krankesjön, when they drove back a small bat flying back and forth along the road on the Revinge field was spotted at 14:20. They managed to get some photos, from which it is apparent we are dealing with a Pipistrellus species. The most common, and hence most likely, species in Sweden is P. pygmaeus (dvärgfladdermus), but P. pipistrellus (pipistrell) and P. nathusii (trollfladdermus) cannot easily be excluded on the basis of the photos. Why are bats emerging from hibernation sometimes flying in daylight? It could be that they are in such a desperate need for energy that they need to feed in daytime; perhaps diurnal insects are more abundant than nocturnal insects at this time of the year? It could also be that the circadian clock has drifted during the winter sleep, which makes them fly at the “wrong” time?
tisdag 23 mars 2010
Browse the table of content here, an overview of the contributing articles is given by Michael Winklhofer, subject editor of this special issue, in his introductory article: Magnetoreception; doi: 10.1098/rsif.2010.0010.focus.
måndag 22 mars 2010
In two recent papers a former PhD student at Lund University, now postdoc in Leiden, Oskar Brattström and co-authors have used stable isotopes and AFLP technique to study the structure of population composition and pattern of migration of European red admirals (Vanessa atalanta) across Europe.
Brattström, O., Åkesson, S. and Bensch, S. 2010. AFLP reveals cryptic population structure in migratory European red admirals Vanessa atalanta. Ecol. Entomol. 35: 48-52. // DOI: 10.1111/j.1365-2311.2009.01163.x
AFLP profiles showed significant differences between almost all sampled locations, but there was no clear pattern of isolation-by-distance. We found two distinct genotype clusters present in different frequencies at all study sites. The frequencies of these genotypic clusters varied significantly between years within the same site. Remarkably few individuals were of mixed ancestry, indicating that some isolating mechanisms are present. Twenty-seven mtDNA haplotypes were identified but they showed no geographic structure, nor were they related to either of the two genotype clusters identified in the AFLP data. Our results suggest long, but more complex migration movements between years for this species. Most field observations of migrating red admirals suggest a regular north–south migration pattern in Europe. Our data indicate both long-distance migration and a more variable pattern in orientation, since the composition of the two genotypic clusters shows dramatic variation between sites and years in the northern part of the distribution range.
Brattström, O., Bensch, S., Wassenaar, L. I., Hobson, K. and Åkesson, S. 2010. Understanding the migration ecology of European red admirals Vanessa atalanta using stable hydrogen isotopes. Ecography // doi: 10.1111/j.1600-0587.2009.05748.x
We also show by using stable isotope that the variation in deuterium associated with a southwest-northeast gradient can be used to assign individual butterflies to general regions of origin. Tracking migratory movement of small animals with variable migration patterns is difficult with standard mark recapture methods or genetic analysis. We used stable hydrogen isotope (dD) measurements of wings from European red admirals Vanessa atalanta to study several aspects of this species’ migration. In the central part of southern Europe we found large differences in dD values between red admirals sampled in autumn and spring supporting the hypothesis that reproduction takes place in the Mediterranean region during winter. There was also an apparent influx to southern Europe in the spring of individuals with a more southerly origin, since many samples had higher dD values and similar to those expected from coastal areas of North Africa. We found a clear seasonal difference in the dD values of red admirals sampled in northern Europe. Spring migrants arriving in northern Europe generally had high dD values that indicated a southerly origin. In autumn, dD values suggested that red admirals were mostly from regions close to the sampling sites, but throughout the sampling period there were always individuals with dD values suggesting non-local origins. The migration pattern of this species is supposedly highly variable and plastic. dD differences between individuals in the western part of Europe were generally small making migratory patterns difficult to interpret. However, butterflies from western Europe were apparently isolated from those from north-eastern Europe, since dD values in the western region rarely corresponded to those of autumn migrants from the north-east. Use of dD data for inferring butterfly migration in Europe is complex, but our study showed that this technique can be used to help uncover previously unknown aspects of red admiral migration.