Travel trip report and slide show from South Africa followed by "Evolutionary Biology for the 21th century"

Navy dropwing (Trithemis furva). Photo: Erik Svensson

Posted by Erik Svensson

During the lab-meeting next week (Tuesday April 2), I will show some nature pictures from our recent research and field work trip to eastern South Africa (from the provinces of KwaZulu Natal, Mupalanga and Limpopo) that I recently did with Anna Nordén, John Waller and Johannis Danielsen. 



After that, we will discuss a recent essay in PLoS Biology, entitled "Evolutionary Biology for the 21th Century", authored by Losos et al. This paper is published "Open Acess", and can be accessed here.

This thought-provoking essay should be an must-read for anyone interested in the future of the general research field of evolutionary biology. The paper has already sparked some interest in the bloggosphere, such as here and here. Of particular interest is their coining of a new term - "Biodiversity informatics", and what it might entail.

The more general questions, I think, are these: are the authors likely to be correct in their predictions about the future of our field, and if not, what have they missed? And where are we in this picture in our research group in relation to the rest of the evolutionary biology research community? How could we contribute?

Time: Tuesday April 2, 10.30
Place: "Argumentet", 2nd floor (Ecology Building)

Final reminder to Anna and John: could you bring fika? Also, send some of your best pictures to me well before Tuesday, so I can put them together in to our slide show.

Open science and "Encyclopedia of Life" - competition for projects

As we all know, our research field (ecology and evolutionary biology) are becoming increasing data-driven and to an increasing extent we are also using data collected by "others" from various internet sources. One such example is our recent paper in Ecology, where we used GBIF-data from thousands of species occurrence records, including from the Swedish source "Artportalen" ("The Species Portal") to model  and understand the environmental factors behind northern range limits in two Fennoscandian demoiselle species (the genus Calopteryx). 

Increasingly, evolutionary biologists interested in organismal biology and phenotypic evolution will use phenotypic data from sources like DRYAD, as has already been used for a long time for molecular data (DNA-sequences), where GenBank is now a common source of information when constructing phylogenies for comparative purposes. Thus, researchers will not only rely on data they have collected themselves (which is often expensive and it is logistically impossible to gather more than a limited amount of data in short time), but can to an increasing extent also use data from public open databases such as GBIF.

Now, another such initiative - Encyclopedia of Life (EOL) - announces a competition for project proposals (deadline November 15). One can propose data-driven projects - a "wish list" - of what kind of data one wants and in what form, and the "best" projects will be realized. This might be an opportunity for someone in our lab (Lesley?), provided that we can come up with a good project proposal to enter this competition. Think about it at least  until November 15.  

Odonates would be an example of a group where distribution data collected from amateur naturalists should ideally be compiled and become available for research projects through open databases. Unfortunately, the odonate research community is small, full of rivalry and have an unfortunate tradition of publishing in low-impact journals. Some odonate researchers and self-appointed experts are also extremely territorial about their collected occurrence data. This type of territoriality certainly hinders scientific progress and the establishment of odonates as respectable model organisms in ecology and evolutionary biology. Science should be characterized by openness and data-sharing - not by rivalry. 

On the evolution of large insects

Posted by Erik Svensson

Our last lab-meeting contained an interesting discussion about the evolutionary significance of large body size in insects, stimulated by the excellent talk by Yuma Takahashi about his ongoing research on Ischnura-damselflies. I thought we should continue on the theme of body size evolution and its drivers in insects, by reading two recent papers that should hopefully be entertaining and interesting.

Both papers discuss the rise and fall of large insects, such as gigantic dragonflies during the Carboniferous Period, and the biotic and abiotic factors driving selection on both body size and wing size. Among the most discussed (but also controversial) idéas is that atmospheric oxygen levels might have been important, but predation has also been suggested to play a role.

Time and place of lab-meeting as usual: "Argumentet" (2nd floor, Ecology Building) at 10.30 on Tuesday September 18 2012. 

Below, you will find the title of the papers and Abstracts and links that should allow you to download the paper if you are on the Lund University network. You can also download them here and here. You might also be interested in the short comment on the latter paper by Steven Chown, which you can download here. 

Environmental and biotic controls on the evolutionary history of insect body size

Author(s): Clapham, ME (Clapham, Matthew E.)1; Karr, JA (Karr, Jered A.)1

Source: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA  Volume: 109   Issue: 27   Pages: 10927-10930   DOI:10.1073/pnas.1204026109   Published: JUL 3 2012

Abstract: Giant insects, with wingspans as large as 70 cm, ruled the Carboniferous and Permian skies. Gigantism has been linked to hyperoxic conditions because oxygen concentration is a key physiological control on body size, particularly in groups like flying insects that have high metabolic oxygen demands. Here we show, using a dataset of more than 10,500 fossil insect wing lengths, that size tracked atmospheric oxygen concentrations only for the first 150 Myr of insect evolution. The data are best explained by a model relating maximum size to atmospheric environmental oxygen concentration (pO(2)) until the end of the Jurassic, and then at constant sizes, independent of oxygen fluctuations, during the Cretaceous and, at a smaller size, the Cenozoic. Maximum insect size decreased even as atmospheric pO(2) rose in the Early Cretaceous following the evolution and radiation of early birds, particularly as birds acquired adaptations that allowed more agile flight. A further decrease in maximum size during the Cenozoic may relate to the evolution of bats, the Cretaceous mass extinction, or further specialization of flying birds. The decoupling of insect size and atmospheric pO(2) coincident with the radiation of birds suggests that biotic interactions, such as predation and competition, superseded oxygen as the most important constraint on maximum body size of the largest insects.

Atmospheric oxygen level and the evolution of insect body size

Harrison, JF (Harrison, Jon F.)1; Kaiser, A (Kaiser, Alexander)2; VandenBrooks, JM (VandenBrooks, John M.)1

Source: PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES  Volume: 277   Issue: 1690   Pages: 1937-1946   DOI: 10.1098/rspb.2010.0001   Published:JUL 7 2010

Abstract: Insects are small relative to vertebrates, possibly owing to limitations or costs associated with their blind-ended tracheal respiratory system. The giant insects of the late Palaeozoic occurred when atmospheric PO(2) (aPO(2)) was hyperoxic, supporting a role for oxygen in the evolution of insect body size. The paucity of the insect fossil record and the complex interactions between atmospheric oxygen level, organisms and their communities makes it impossible to definitively accept or reject the historical oxygen-size link, and multiple alternative hypotheses exist. However, a variety of recent empirical findings support a link between oxygen and insect size, including: (i) most insects develop smaller body sizes in hypoxia, and some develop and evolve larger sizes in hyperoxia; (ii) insects developmentally and evolutionarily reduce their proportional investment in the tracheal system when living in higher aPO(2), suggesting that there are significant costs associated with tracheal system structure and function; and (iii) larger insects invest more of their body in the tracheal system, potentially leading to greater effects of aPO(2) on larger insects. Together, these provide a wealth of plausible mechanisms by which tracheal oxygen delivery may be centrally involved in setting the relatively small size of insects and for hyperoxia-enabled Palaeozoic gigantism.

Greetings from Austin (Texas)

Posted by Erik Svensson

After about two weeks in Texas, around its capital Austin, I am heading home to Sweden again, after a very nice visit to my colleagues at Section for Integrative Biology at University of Texas. This department is certainly one of the strongest in ecology, evolution and behaviour in the US, and I can strongly recommend a visit here. Interestingly, they do not have any bird research at all, but most empirical work is on fish on insects, and the department is particularly strong in animal behaviour, sexual selection, neurobiology and evolutionary population genetics. This is the second time I visit, and I gave a talk already in spring 2003, nine years ago. Remarkably, almost all who attended my talk then were here this time as well, including Mark Kirkpatrick, Mike Ryan and legendary lizard evolutionary ecologist Eric Pianka.

I also met with some new folks, which have arrived since 2003, including PhD student Eben Gehring who works in the lab of Molly Cummings, and who does research on Ischnura-damselflies and evolutionary ecology professor Dan Bolnick, with whom I share many research interests, including the evolution of assortative mating and its consequences. Tonight, I am going to dinner with Scott Edwards, who is also visiting from Harvard this same week as I am here, and who will be the opponent of PhD-student Anna Runemark in our lab on May 25 next month.

Apart from Monday, this week, when I gave my talk, I have spent most time in the field, looking for and researching on Texas odonates. You can see one particularly stunning species that I saw here. Texas is especially species-rich, as half of North America's species occur here, more than 250 species, and several tropical elements from Mexico and Central America. As a comparision, Sweden has about 55 species, less than a fifth of Texas (although it should be said that Texas is slightly bigger than Sweden - everything is bigger in Texas, actually!). It is good to keep in mind that biodiversity is quite low in Europe, mainly due to the effects of past ice ages, and perhaps our faunas have not yet even been saturated, as re-colonziation from the last Ice Age might still be ongoing?

Dr. Yuma Takahashi receives postdoctoral scholarship from Japan to join our lab

I am pleased to announce that Dr. Yuma Takahashi from Japan has been awarded a three-year postdoctoral scholarship, and will join our laboratory in 2012. Yuma received his doctorate degree at University of Tsukuba and in his thesis work he studied female colour polymorphism, frequency-dependent selection and evolutionary dynamics of the damselfly Ischnura senegalensis. You can read more about Yuma's research here. His study organism (I. senegalenis) is a small coenagrionid damselfly is closely related to Ischnura elegans, which we have studied in our lab.

There are many interesting similarities, but also difference between these two polymorphic species. One major difference, though, is that Ischnura senegalensis has only two female morphs, not three as in Ischnura elegans. Another interesting ecological difference is that the male mimicking androchrome females are often in minority in I. senegalensis, or at least not much more than 50 % of the female population, whereas this female morph is often the most common morph in I. elegans (at least in Sweden where we have mainly studied it). These interesting ecological species differences will hopefully be understood better and be explored after Yuma joins our lab in 2012.

Yuma has already published eight papers from his thesis-work and here I would just like to point to his latest one, which recently appeared in the journal Evolution. Using a powerful combination of field observations and experiments and simulation modelling, they elegantly illustrated the evolutionary dynamics of this polymorphic system which strongly suggest that this dynamic is most likely the result of frequency-dependent sexual conflict interactions, caused by male-female antagonistic mating interactions. In short: males develop a "search image" for common female morphs, and common morphs become differentially sexually harassed, resulting in an inverse relationship between a morph's fitness and its frequency in the population, which leads to negative frequency-dependent selection (NFDS), a very powerful evolutionary mechanism to maintain genetic polymorphisms. 

These findings and conclusions by Yuma and his co-workers are very similar to our paper on I. elegans that we published in 2005 in American Naturalist. It is of course nice to see that the genus Ischnura continues to generate interesting studies and inspire evolutionary biologists in different countries, including Japan. As an aside, the next international dragonfly conferences (WDA) will also take place in Japan, south of Tokyo between July 31 and August 5 2011. I am very happy and flattered to become invited as a plenary speaker to this rather small meeting of odonate enthusiasts, amateurs, naturalists and researchers.

Below is the Abstract and link to Yuma's article in Evolution, for those who are interested in reading more about this fascinating species and study system:

Negative frequency-dependent selection in female colour polymorphism of a damselfly (Evolution 2010 64: 3620-3628)

Takahashi, Yuma, Yoshimura, Jin), Morita, Satoru) & Watanabe, Mamoru

Abstract: Negative frequency-dependent selection (NFDS) is one of the most powerful selective forces maintaining genetic polymorphisms in nature. Recently many prospective cases of polymorphisms by NFDS have been reported. Some of them are very complicated, although strongly supportive of the NFDS. Here we investigate NFDS in wild populations of the dimorphic damselfly Ischnura senegalensis, in which females occur as andromorphs and gynomorphs. Specifically, we (1) test fitness responses to morph frequencies, (2) built a simple population genetic model, and (3) compare the observed and predicted morph-frequency dynamics. Fitnesses of the two morphs are an inverse function of its own frequency in a population, and are about equal when their frequencies are similar. Thus the conditions necessary for NFDS are satisfied. The long-term field surveys show that the morph frequencies oscillate with a period of two generations. Morph frequencies in a small population undergo large oscillations whereas those in a large population do small oscillations. The demographic properties of the observed dynamics agree well with those of our model. This example is one of the simplest confirmed cases of NFDS maintaining genetic polymorphisms in nature.

Interesting video about dragonfly migration over the oceans

Whatch this very interesting video by Charles Anderson, that is well worth watching. It deals with the newly discovered trans-continental dragonfly migration between India and Africa and describes how it was discovered. Enjoy!

This week there will not be a lab-meeting the coming Wednesday (20 January), since I will be in Germany, giving an invited lecture at Museum fur Naturkunde in Berlin, which is part of the famous Humboldt University. This university has had many famous students during its 200 year existence, among them Friedrich Engels, Karl Marx, Max Planck, Albert Einstein and Karl Liebknecht. The natural history part of the museum is well known for its paleontological collections, particularly one of the finest specimens of Archaeopteryx - the "missing link" between dinosaurs and birds. I will of course return with a detailed report when I get back.

For next week (25-29 January), the aim is to have a lab-meeting on Monday 25 January at 09.30 in "Argumentet" about insect flight and wing morphology. Sophia Engel will be responsible for announcing this seminar by putting up a bloggpost with a link to the paper(-s) that we will discuss. This will be a joint meeting with Anders Hedenströms group "Animal Flight Lab". Sophia should put up the post well ahead of Monday, preferably later this week, with some help of more experienced bloggers in the group, if necessary.

Wednesday: Dragonfly excursion!

For those of you who are interested, there is a possibility to participate in a dragonfly excursion on Wednesday, instead of our regular lab-meeting. Because of nice weather, I think we should skip lab-meetings from now, and instead spend time in the field (or lab, if we need to).

However, those of you who can are welcome at Stensoffa Ecological Field Station at 09.00 on Wednesday. If you go by your own car, you can decide to go back when ever you want (e. g. after a few hours), but I will probably spend more or less the whole day in the field visiting my census plots for the Official Dragonfly Census in Skåne that has just taken off and will run for the next five years. This is an excellent opportunity for those of you who wish to learn how to identify dragonflies. Everybody are welcome to book one or several census plots (5 x 5 km), which can be done by contacting these persons, and no special expertise is needed.

In case you cannot arrange transportation, there is also the opportunity to take the bus to Dalby and go with me, or send me an e-mail (erik. svensson@zooekol.lu.se).

Quizz of the week: Which species of odonate is shown above?

Dragonfly season has started!

This weekend I spent a few hours in the field and the first odonates have already emerged! It appears as it will be an as early season this year as last year, and we probably need to start to catch Ischnura elegans soon. Hopefully, the Calopteryx-season will still not start until early June. This means that lab-meeting on Wednesday will be at the Ecology Building (as planned), when we will see the second part of "Life in Cold Blood", although the week after is an open issue (at least to me). Depending on weather, we might do a joint field trip, although I want to keep this day open for other possibilities, depending on weather.

For this week, I suggest that we skip the TREE-article I suggested last week, as I feel it will be a bit too much with both that article (a rather heavy one!) and the movie. I hope nobody objects to this. Time and place as usual: "Darwin" at 10.15 (Wednesday 6 May). Could Shawn bring popcorn or somebody else this week?

Quizz: Which species of dragonfly is depicted above? It is a very common species that is one of the earliest fliers in the season.

Lab-meeting on Wednesday April 1: Flight of dragonflies!

In light of the recent and very succesful CAnMove meeting on the interface of physics and biology, it seems appropriate to have next lab meeting focus on the interface of physics and odonatology. In particular, flight.

We've chosen two chapters out of the book Dragonflies and Damselflies: Model Organisms for Ecological and Evolutionary Research (edited by Cordoba-Aguilar, 2008). Both chapters are at the end of the book, and are short:

Chapter 19: Dragonfly flight performance: a model system for biomechanics, physiological genetics, and animal competitive behavior (Marden)

Chapter 20: Evolution, diversification, and mechanics of dragonfly wings (Wooton and Newman).

If you do not own this book, both chapters can be found in Shawn Kuctha's mailbox (2nd floor, Ecology Building), where you can copy them. Alternatively, you could contact him directly (shawn.kuchta@zooekol.lu.se).