You are here


  • Post date: 1 month 5 days ago
    Citation for this post: BibTeX | RIS

    In a published in Animal Behaviour in 1977, , , Michael Webber and showed experimentally that whether great tits (Parus major) are selective or not about prey choice depends only on the supply rate of the more profitable prey, and not of the less profitable prey. These findings partially supported a model of optimal foraging that they had developed. Twenty-four years after the paper was published, I spoke to John Krebs about the making of this study and what we have learnt since then about foraging decisions of great tits.

     (Questions sent by email on 10 August 2016; responses received on 10 August 2016)

     Citation: Krebs, J. R., Erichsen, J. T., Webber, M. I., & Charnov, E. L. (1977). Optimal prey selection in the great tit (Parus major). Animal Behaviour, 25, 30-38.


    Hari Sridhar: What was your motivation to do the experiments presented in this paper?

    John Krebs: To test a model of optimal prey selection


    HS: This paper has four authors. Could you tell us how this group came together and what each member of the group contributed to this study?

    JK: Erichsen designed the apparatus, Charnov did the modelling, Webber and I ran the experiments and the analyses.


    HS: Who were the two observers - one who replenished the food and the other who watched the video monitor - during this experiment?

    JK: Sometimes Krebs and Webber, and sometimes Krebs and Erichsen.


    HS:  How did you come up with the idea of using a conveyor belt apparatus for this experiment? Would you know whether the apparatus that you used still exists?

    JK: Erichsen had designed the apparatus for another purpose. I doubt that it still exists


    HS:  Where and by whom were the four great tits caught? How did you find the fifth bird, which was raised from an age of 12 days?

    JK: They were caught by Krebs at , the fifth was hand raised by Krebs.


    HS: Could you share with us what the codes 'bw', 'gbw', 'ro', 'yy' and 'pw' stand for?

    JK: Colour ring codes: blue, white, green, red, orange, yellow, pink


    HS: During the writing of this paper, how did the authors share, discuss and edit drafts of the manuscript? Would you remember how long the writing took?

    JK: Don’t know how long it. Krebs wrote the draft and others commented


    HS: Did this paper have a relatively easy ride through peer-review? Was Animal Behaviour the first journal you submitted this to? 

    JK: We didn’t submit it elsewhere.  I don’t recall how the referees commented on it


    HS: Were these results considered controversial soon after they were published? Did this paper receive a lot of attention from peers?

    JK: The results weren’t controversial. The paper was, I think, well-received.


    HS: Did this paper play a role in influencing the future course of your research career?

    JK: It was one of our early papers on foraging theory, which formed a major research focus of my group for the following decade.


    HS: Today, 39 years after it was published, would you say that the main conclusions of this study still hold true?

    JK: I have no reason to doubt the results, but corrected the theory, and were unable to repeat the results in toto.


    HS: If you were to redo these experiments today would you do them differently?

    JK: Yes.


    HS: In the paper you say "it will be impossible to distinguish between 'mistakes' and 'deliberate sampling' until we have devised a specific predictive sampling model". Was such a model developed subsequent to this paper?

    JK: Yes.



    HS:  You say that "our failure to find this [a step change from no selection to selection for profitable prey] in our experiment is likely to be a general result". Was this statement borne out by future research? 

    JK: See


    HS: In the 39 years since it was published, have you ever had to go back and read this paper for any reason?

    JK: I did in the early days but not recently


    HS:  Among all the papers you have published, is this one of your favourites? If yes, why? 

    JK: It was one of our early papers testing optimal foraging models.  In hindsight the theory and experiments could have been improved


    HS: What would you say to a student about to read this paper today? What should he or she take away from this paper written 39 years ago?

    JK: I would say it is a good example of how to link theory and experiment, but also that by today’s standards it is not a very sophisticated piece of work and much has been done since then to develop both the theory and experimental techniques.


  • Post date: 1 month 1 week ago
    Citation for this post: BibTeX | RIS

    In a published in Science in 1999,  and a team of collaborators reported the results of an experiment, replicated in eight European field sites, that showed that loss of plant species diversity leads to reduced above-ground plant biomass. Seventeen years after the paper was published, I spoke to Andrew Hector about the making of this project and what we have learnt since about the diversity-productivity relationship.

     (Questions sent by email on 30 July 2016; responses received on 18 September 2016)

     Citation: Hector, A., B. Schmid, C. Beierkuhnlein, M. C. Caldeira, M. Diemer, P. G. Dimitrakopoulos, J. A. Finn et al. 1999. Plant diversity and productivity experiments in European grasslands. Science 286: 1123-1127


    Hari Sridhar: Please tell us a little about the motivation for setting up this multi-country experiment. Whose idea was it? Was it setup specifically to investigate niche complementarity and sampling effects?

    Andrew Hector: Research on the link between biodiversity and ecosystem functioning only coalesced as a field following a conference in the early 90’s put together by Detlef Schulze and Hal Mooney. That meeting spawned several studies. Interestingly, the link between diversity and function but there was only sporadic study of it until the 90s. The multi-country approach of BIODEPTH was facilitated by the European Framework 4 – we had about a dozen groups in 8 countries led by at the NERC Centre for Population Biology at Imperial College Silwood Park.


    HS: You joined the BIODEPTH project soon after you completed your PhD. Can you share with us how you got into this project?

    AH: Luckily, I spent much of the previous year working for at Imperial College, monitoring on-going experiments and helping set up new ones, to earn money while I wrote my PhD up. That put me in a good position when the postdoc. came up for BIODEPTH.


    HS: Please give us a sense of how this collaboration worked. How did people join this group? Did all of you meet anytime during the making of this study? Did you have regular online meetings?

    AH: BIODEPTH was a success because of the great collaborative spirit - it was a real team effort and everyone in it made an important contribution to its success. The Framework 4 structure had meetings every 6 months and we worked our way around most of the sites.


    HS: How did the writing of this paper happen? Did you do most of the writing? How were drafts shared and commented upon?

    AH: The paper was born at one of the regular meetings. It was hard to explain to people how to send the data in for inclusion in the database so we went through the whole process in a mock example and then did a basic statistical analysis there and then. Seeing how quickly it could be done really motivated people to get the data sent in speedily.


    HS: Did this paper have a smooth ride through peer-review? Was Science the first place you submitted this to? In what ways did the published version differ from the first submitted draft?

    AH: Yes and no. Science were happy to have it but it had mixed reviews – some scientists were (and still are) quite against the whole idea that diversity can be important for functioning. To some degree, the final paper was a compromise between opposing reviewer opinions.


    HS: In the Acknowledgements you thank "P. Heads and E.Bazeley-White" - can you tell us how these people helped? You also thank J. Nelder for advice on statistical analyses" - can you tell us more about this?

    AH: Phil Heads managed the NERC Centre for Population Biology for John (he was one of his ex-PhD students) and Ellen managed the database (she is now at British Antarctic Survey). It was great to have both of them to help support the work. was a very influential statistician. We hired him to hold a short workshop where we could bounce ideas for the analysis off him.


    HS: You say you used "standardized protocols to establish experimental assemblages ". Can you tell us a little more about these protocols?

    AH: The details are too technical to go into here. The key point was that each team followed the same approach at the different field-sites to make the data as comparable as possible.


    HS: Did this paper attract a lot of attention - in academia and in the media - when it was published?

    AH: Yes. Interestingly, the media did not find the idea controversial - it seems to make sense to people that biodiversity affects how ecosystems work – but some scientists did.


    HS: What impact did this paper have on your career and the future course of your research?

    AH: Obviously getting my second publication into Science was a huge break – I was very lucky to have had the opportunity.


    HS:  It is now 17 years since this paper was published - would you say that the main conclusions from this study still hold true?

    AH: Yes, in general. We have realized many scientific results are not reproducible (‘the reproducibility crisis’) but the BIODEPTH results turned out to be very reproducible despite being controversial with some people. The experiment has been repeated in , , and elsewhere and all results fall in the range seen in our study.


    HS:  If you were to redo these experiments today, would you do anything differently, given the advances in technology, theory and analytical techniques?

    AH: We tried to manipulate both species richness and functional groups and although their effects cannot be totally separated (more groups means more species) it would have been nice to have teased them apart a bit more (although did this for legumes, omitting them from their study). We used random mixtures of species due to some practical constraints. It might have been nice to use mixtures that reflected how species might be lost in reality, but this is hard to predict and depends on what is driving species loss. And, on the other hand, randomization is a key feature of good experimental design and a good place to begin.


    HS:  In the paper you say that this was "the most extensive experiment to date in terrestrial ecosystems." Since then, have there been bigger experiments on this topic?

    AH: At single sites yes (Cedar Creek and Jena), and BIODEPTH seems to have been partly responsible for the current popularity of networks (coordinated distributed networks) like Nutrient Network and Drought-Net.


    HS: Did the work presented in this paper serve as a motivation for ?

    AH: Yes. Basically we had a pattern, but could not pin down the mechanism. The 2001 paper helped us to do this.


    HS:  In your paper you say that "There may also be transient effects at this early stage of the experiment that largely disappear by the following year". Can you tell us whether this has happened in subsequent sampling?

    AH: Sadly, the EU framework 4 only allowed us to keep the 8 sites going for 3-4 years (some ran for longer) but longer term work at Cedar Creek and Jena has shown the effects generally get stronger over time as the experiments go on.


    HS: At the time of this study, Trifolium pratense was the only species that had particularly marked effects on productivity. Since then have other important species been discovered?

    AH: Actually, that result has to be taken in the context that red clover was one of the few species grown at all sites. I don’t doubt it has strong effects (it is a nitrogen fixer) but the design could not get at the effects of all species.


    HS: What is the status of the plots used in this study? Do they continue to be used for these experiments? Have the sites in which these plots are located undergone any changes since the time of this paper?

    AH: As I said above, sadly we could not keep the study going in the long term but the projects at Cedar Creek and Jena are still going.


    HS: At the time you did this study, did you anticipate that it would be cited so much? Do you know what this paper has been mostly cited for?

    AH: I didn’t really think about it but it was a new field and a controversial topic so it is not surprising. It is cited as evidence that biodiversity affects how ecosystems function.


    HS: Have you ever read the paper after it was published? When you read it now, what strikes you the most about it?

    AH: Not recently. I remember there is a mistake in it – at one point we say species richness affected diversity (when we meant productivity).


    HS: What would you say to a student about to read this paper today? What should he or she take-away from it?

    AH: That it is important to repeat the same study to see how repeatable or variable the result it.


    HS: Is this your favourite paper among all the papers you have published? If yes, why? If no, and if you do have another favourite, which is it and why?

    AH: It seems a long time ago now (it was!) but obviously it will always be one I remember. My other current favourites are:




  • Post date: 1 month 3 weeks ago
    Citation for this post: BibTeX | RIS

    In r published in Nature in 1982, showed, experimentally, that female choose mates based on the lengths of their tails. Andersson’s study was, arguably, the first experimental support for . Thirty-four years after the paper was published, I spoke to Malte Andersson about the making of this study and what we have learnt since about mate choice in widowbirds.

     (Questions sent by email on 7 July 2016; responses received on 17 September 2016)

     Citation: Andersson, M. (1982). Female choice selects for extreme tail length in a widowbird. Nature 299: 818-820.


    Hari Sridhar: What was your motivation for doing this study ? How and when did you first come to know about long-tailed widowbirds?

    Malte Andersson: My interest in sexual selection and signaling was seeded around 1970, during my doctoral studies of behaviour and ecology of long-tailed skuas in Lapland, Northern Sweden. The long-tailed skua is a relative of auks and gulls, and turns rodent predator in the far North during the breeding season. Inspired by the comparative ethological studies of gulls by ’s group, my aim was to study skua behaviour and its adaptations to an ecological lifestyle very different from that of its phylogenetic relatives. I was aware that both sexes in skuas have a pair of elongated central tail feathers that differ markedly in shape and length among the four Northern hemisphere species. In the field, I found that both sexes raise and expose the tail conspicuously during courtship, and I wondered about its function. Perhaps the elongated feathers are important for species recognition in pair formation? But at their breeding grounds, the species are easy to tell apart for a human observer, based on size, calls, coloration and other aspects. So why should the birds need different tail shapes for that purpose? Species recognition did not seem an entirely plausible hypothesis. On the other hand, catching the same individuals over several years, I found that the central tail feathers became longer and therefore reflected age and perhaps also survivorship. I wondered if that might somehow be relevant.

          About a decade earlier, Peter O’Donald, ’s last doctoral student, had studied sexual selection of color morphs in Arctic skuas. Reading his pioneering papers made me aware of Darwin’s and Fisher’s theory of sexual selection by female choice. I also read widely outside the curriculum, visiting our university library each weak, skimming journals in behavior, ecology and evolution for interesting new studies. I was also influenced by books on evolution, selection and adaptation by , and , which strengthened my interest in evolution. After my dissertation, these research fields, in particular sexual selection, full of interesting theory and unsolved problems, were on my mind. During a visit to East Africa in 1975, I saw long-tailed and Jackson’s widowbirds on their savanna breeding grounds in the Kenyan highlands. Why were male long-tailed widowbirds, with their black plumage, red wing epaulet and, especially, a half meter long unwieldy tail, so different from the females, which resembled dull females of other weaverbirds (Ploceidae)?


    HS: This is the first test of Darwin's hypothesis about male sexual ornaments. Why do you think it took so long for it to be experimentally tested?

    MA: Most biologists for a long period were skeptical about Darwin’s ideas on mate choice, and many remained skeptical even after the ‘’ in the mid 1900’s (e.g. , ). And, in spite of early pioneering work by Niko Tinbergen, experimental tests of behavior in the wild gained momentum only in the 1970’s and 80’s. Then, new results made it increasingly clear that field experiments in the natural environment could often provide decisive results and distinguish between hypotheses in behavioral and evolutionary ecology, clarifying the function and adaptive significance of a trait. Controlled field experiments thereafter became more common.


    HS:  During this study, what was a typical day in field like?

    MA: Usually going to the field site a while after sunrise, when widowbird males returned to their grassland territories from the night roost. We caught territorial males with a clap-net trap. Before and after catching and manipulating a male, I measured his display activity. After the sun dried out the morning dew from the tall grass, I searched for nests of females breeding in the territory, doing so once a week until the end of the breeding season.


    HS:  You started the fieldwork for this study in November 1981. In the same month, you wrote was accepted in the Biological Journal of the Linnean Society. Did this paper, in some way, motivate your study on widowbirds?

    MA: Yes, in a general way, as work on theoretical aspects of sexual selection made me read and think about debated issues of female choice and male ornaments. was one possibility, and it also seemed likely to me that ornaments could indicate phenotypic and genetic fitness, through resource allocation, as portrayed in a figure in the paper you mention. I thought that, in spite of lingering skepsis among many researchers, female choice based on male ornaments was plausible, encouraging me to attempt an experimental test.


    HS: Did you do all the fieldwork on your own or did you have help in field?

    MA: In catching the birds and during the experimental manipulations, a field assistant, first Uno Unger, then Kuria Mwaniki, helped me. He held the male in a suitable position, while I cut and glued the tail feathers. This way there was no need for anesthetics, and the bird could be released immediately after being manipulated and ringed.


    HS:  How difficult was it to find the nests?

    MA: It was more time-consuming than difficult. Females build their rather large-domed grass nest in the upper third of 0.5 – 0.8 m tall grass in the male’s territory. Females usually flew from the nest when I was several meters away. By systematically searching the grass areas of the territory in parallel walks about 2 m apart, I located the nests, and I repeated the search each week until the end of the breeding season, when no new nests were started.


    HS: Walk us through how you came up with the idea of modifying the tail lengths of these birds? Was it tricky to cut and paste the tail feathers back? Did you use a particular brand of glue for this?

    MA: Controlled field experiments was an approach I had used in several earlier studies during work with skuas and lemmings in Lapland. And I was aware of the . So, experimental testing of a conspicuous male ornament, potentially involved in female choice, was not a far-fetched approach. In fact, I had been thinking about this possibility for a long time, but then with the epitome of male ornaments in mind: the train of the peacock. I explored possibilities for doing such a field experiment during a visit to Sri Lanka in 1979, but found that such a study of peacocks in the wild would be difficult for several reasons. The lek sites I found in a national park were in jungle with plenty of elephants and wild buffalo around; not an ideal situation. In addition, manipulating trains of unwilling peacocks in the wild seemed to present some problems of its own.  That made me think again about the African widowbirds, which appeared more manageable.

          When I planned the experiments, rapidly hardening cyanoacrylate superglue was coming on the market. The brand I used was called . Testing with feathers from other birds, I found that the glue hardened quickly enough, in just a few seconds, to be suitable for use in the field for tail elongation. I practiced and improved my skill at feather manipulation at the lab before going to Kenya for the study. During manipulations in the field, the assistant sat in front of me holding the bird, while I cut, trimmed and glued the tail feathers.


    HS:  Fig. 1 in this paper is one of the nicest figures I have seen in a scientific paper. Whose idea was it to include the widowbird illustrations perched on the bars in the graph? How was this figure made at that time?

    MA: I thought carefully about how to include, without overloading the figure, as much information as possible. For instance the number of nests for each individual male at the bottom of the bars. The idea of having perched widowbirds with relevant tail lengths on the bars came rather naturally, because this was the way I often saw males in the field. There were many cattle fences in the area, and fence poles were the favorite perch sites for territorial males. I made the first version of the figure, which was then redrawn in ink by a departmental lab assistant, Aino Falk Wahlström, skilled at illustration work.


    HS:  One of the unique aspects of your study is the elegant “double control” you used for the experiments. Was this the first time such a design was being used?

    MA: I am not aware of any previous study with such a design, but it may well have been used before. I first planned to use only the color-ringed birds as control, but became worried that the cut-and-glue operation might have an important effect, so added a control for that.


    HS:  Your paper presents a lot of natural history information on the widowbird. Was this already known or did it come from your own observations?

    MA: Some of it was known from earlier studies of the South and the East African subspecies (e.g. ). Other aspects I learned during fieldwork.


    HS:  Today, do we know more about aspects of this bird's ecology which weren't well-known then, e.g. nest-site choice by females, role of tail length in competition, and territory ownership?

    MA: There has apparently not been much more fieldwork on this species, but several other widowbirds have been studied extensively by observations, experiments and comparative phylogenetic analyses, in particular by my former PhD student (no relative!) and his research group.


    HS:  Today, do we know more about why females choose long-tailed males in this species?

    MA: Our knowledge about mate choice in other widowbirds, and of course more generally, has increased vastly in the 34 years since the study was published, but there have been no further studies of mate choice in this species. The reason may be that a number of other widowbirds, whydas and other species also have long tails. Researchers have apparently preferred to study some of these other species rather than the one I already studied. Focusing on another species permits both another independent test of tail function, and can show if ornamental long tail plays a role in female choice more generally among birds. A number of studies of different species have found that it does.  


    HS:  Your work was entirely experimental. Have there been studies looking at whether your findings hold true with respect to natural variation in males?

    MA: Not in this species, but in many other birds, studies based on natural variation have found that male mating success correlates with ornament size.


    HS: Did this paper create a buzz - within academia and outside - when it was published?

    MA: Yes, it raised much interest among biologists, demonstrating sexual selection by mate choice of a conspicuous ornament, of the kind that long puzzled Darwin, until he arrived at the essentially correct explanation. It also raised interest in general news media, some of which reported that now it has been proved: the length matters.


    HS:  How important has this paper been in your career? Has it had a major influence on the course of your future research?

    MA: It had a major influence. Sexual selection is a field full of both fascinating natural history and interesting debated theory. Partly as a consequence of the simultaneous publication of the widowbird study and my theoretical paper in Biological Journal of the Linnean Society, I was invited by editors at Princeton University Press to write . Not anticipating the eruption of coming studies I gladly accepted. That decision kept me busy for a number of years. When the first version of the book manuscript was finished, it was necessary to revise almost every chapter, because so many new important results had been presented in the meantime. And the same procedure had to be repeated again also when the revision was finished, until I could finally deliver a manuscript that was reasonably up to date with the latest findings. Writing the book greatly reduced my available time for widowbird work and other research. Fortunately Staffan Andersson, after presenting his thesis on Jackson’s widowbird, could continue comparative and experimental studies of sexual selection of coloration and other ornamental traits in widowbirds and bishops, which remains a successful ongoing project. After gaining more time for own research when the book was finished, I have worked for instance on various aspects of breeding systems.


    HS:  Have you ever gone back and read this paper after it was published? What aspects about it strike you now? What memories does it bring back?

    MA: Yes, I have read the paper in preparing some talks and lectures. A nice aspect is its brevity. The experimental design, planned after a pilot visit to the study site a year before the experiment, made the outcome rather clear and easy to write about, resulting in a short informative paper. Reading it now recalls exciting fieldwork in a beautiful rural part of the Kenya highlands, with cool nights and hot sunny days, helpful and friendly Kikuyu farmers, and the Nyandarua Mountains as a magnificent backdrop under a clear sky. (There were thunderstorms and torrent rains too, but they seem to have thinned out in my memory.)


    HS: If you compare this paper to papers you write today, do you find any striking differences, e.g. in writing style?

    MA: Not that I am aware of. I try, but of course fail, to write as simply and briefly as possible, without sacrificing clarity and readability. A researcher that in my opinion wrote lucidly about quantitative evolutionary problems was John Maynard Smith. Authors with such writing style were for instance and .


    HS:  Have you had the opportunity to go back to your study site after the paper was published? Has the site changed a lot since the time you worked there, in 1981-82?

    MA: I have not been back since the mid-1980s, but even then, some of the breeding habitat of long-tailed widowbirds was disappearing, being turned into arable fields or plots for growing vegetables, and the nesting grass (Eleusinae) was being cut for thatching of roofs.


    HS:  This paper has been cited 793 times (Google scholar) as of today. Did you anticipate that it would generate so much interest? Do you know what your paper has mostly been cited for?

    MA: I had no idea it would raise so much interest. It has probably been cited mostly because it experimentally demonstrated female choice based on a conspicuous male ornament in the wild.


    HS:  What would you tell a student who is about to read this paper today? Any caveats? What should he or she take-away from it?

    MA: I spent much time thinking about the experimental design, and exploring the possibility for such a study by a pilot visit to the field site. So the importance of careful planning is probably a useful takeaway. Viewed today, there are many caveats. For instance, there is no paternity determination, as DNA methods were not then available. And the adaptive reasons for female choice of males with long tail could not be studied in this brief experiment. But the successful experimental demonstration of female choice in the wild may have helped encourage subsequent better studies.


    HS: Among all the papers you have written, is this your favourite?

    MA: Yes, I believe it is my best paper because it is short and informative, reporting a fairly clear outcome of a controlled, interesting experiment. It demonstrated, in the wild, female choice of mate based on a conspicuous ornament, one of Darwin’s most controversial ideas. Another often cited sexual selection paper is a model () showing that a genetic indicator process of mate choice can work, taking to higher frequencies a female preference and a preferred male ornament that reflects genetic viability. This, together with similar results from other researchers, may have helped generate more interest and more sophisticated modeling and empirical testing of such processes in sexual selection.



  • Post date: 2 months 11 hours ago
    Citation for this post: BibTeX | RIS

    Contributed by Sofía Campana, Georgina Conti, Florencia Spirito and Laureano Gherardi

    The was held on  September 18th to 23rd, 2016 in Puerto Iguazú, Argentina. This small town is known for its proximity to the Iguazú Falls, one of the Seven Natural Wonders of the World. It is situated within one of the biggest remnants of Atlantic Forest, which is a biodiversity hotspot in South America. This natural setting provided a perfect atmosphere for our meeting, which theme was “The challenge of integrating society and nature: proposals from ecology". 

    The Binational Meeting of Ecology is organized every two years by the ecological societies of these two neighbouring countries: the Chilean Society of Ecology () and the Argentinian Ecological Association (). This year, more than 600 ecologists attended the meeting, including undergraduate and postgraduate students, researchers and natural reserve managers from Argentina, Chile, Uruguay, Brazil, Paraguay, Ecuador, Mexico, United States and Spain. The meeting consisted of six plenary conferences, 25 symposia, seven courses/workshops, 27 oral sessions (with ca. 200 speakers) and more than 300 poster presentations.

    The challenge of linking nature and society

    This year, the ecological meeting highlighted a main challenge across ecologists: to address the need to make a theoretical and empirical link in continuous feedback between natural ecosystems and human societies. This was reflected across plenary conferences, starting with Ulysses Alburqueque (Federal Rural University of Pernambuco, Brazil) proposing the need to consider humans as ecosystems engineers in ecological approaches. He showed a controversial framework that generated several interesting questions and debate across attendees. This first plenary was followed by several symposia addressing agroecology, etnobiology, etnoecology, etnozoology, ecological restoration, eco-economy concluding the first day with a plenary conference leaded by Irina Izaguirre (University of Buenos Aires, Argentina) showing the effect of anthropogenic changes in aquatic ecosystems embedded across the Argentinian Pampa.

    A very interesting and enjoyable plenary conference was the one proposed by Patrick Lavelle (Pierre and Marie Curie University, France) showing the complexity of underground systems continuously evolving over time. In this context, conventional agriculture acts disrupting and turning back processes and systems, making soils simpler and poorer in terms of biological activity. He proposed a redefinition of agriculture in particular, and managed landscapes in general, calling for special research attention on the restoration of anthropized ecosystems.

    Plenary conferences called for a change in the general paradigm conducting ecological research in southern South America, as was pointed out by Audrey Grez (University of Chile) and repeated across symposium, oral and poster sessions: there is a bias in ecological studies towards the study of natural ecosystems where managed or disturbed ecosystems are underrepresented even though these managed ecosystems support most food provisioning services contributing to human well being.

    INNGE: “Seeds in the South”

    Last year a small group of young ecologists from Argentina started the South American INNGE sub-group, called “INNGE: seeds in the South”. For our inaugural event we organised the symposium entitled “The ecology and the ecologists to come: challenges and opportunities in the next decades”. We were motivated by our joint vision for the future of ecology, and the slogan of the meeting was a perfect framework for our first symposium as INNGE South America. We invited five inspiring speakers who are leaders in ecological science to talk about three key topics: (i) academia and the role of ecologists in society (, ), (ii) cooperative networks in ecology (), and (iii) science communication beyond scientific literature (). The symposium was a great success and very well attended, with high levels of participation from the audience. After the symposium, a lot of people showed interest in being involved and collaborating with other INNGE activities across South America. It was a great first step for us! At present, we are actively participating together with a group of more than 30 researchers, putting together several ideas and discussions of collaboration, evaluation of the actual situation and future goals of early career ecologists.

    If you would like to collaborate or know more about the group “Seeds in the South”, you could write to:

  • Post date: 2 months 3 days ago
    Citation for this post: BibTeX | RIS

    In published in Animal Behaviour in 1991, , and Carolyn Sanders showed, through an observational study, that: 1. mating success of male peacock was related to the number of spots on their tails; 2. the relation between mating success and number of tail spots was a result of female choice, i.e. females preferentially mated with males with a greater number of tail spots. Twenty-five years after the paper was published, I spoke to Marion Petrie about the making of this study and what we have learnt since about the tail of the peacock.

     Questions sent via email on 1st July 2016; responses received on 21st September 2016

     Petrie, M., Tim, H., & Carolyn, S. (1991). Peahens prefer peacocks with elaborate trains. Animal Behaviour, 41: 323-331.


    Hari Sridhar:  In the Introduction of your paper you cite only three references. One is Darwin. The other two are studies that manipulated a male character and measured mating success. What role did these studies play in motivating your work?

    Marion Petrie: Although Darwin first suggested that the peacock’s train had evolved as a result of female choice, no one had tested this idea. I was working at Whipsnade Park on a study of Chinese Water Deer, and, whilst staying overnight in the park, noticed the free-ranging peacocks displaying in groups (lekking).  I thought that it would be feasible to study the peacocks at Whipsnade (that it would be relatively easy to catch and mark them) and test Darwin’s hypothesis.  The beauty of a lek mating system is that the process of active female choice is directly observable.


    HS: This paper has three authors. How did this group come together and what was the contribution of each author? Who did most of the writing?

    MP: Tim Halliday held a lectureship at the Open University, which was the closest University to Whipsnade Park, and had an interest in mate choice.  I met Tim at a conference and talked about studying the peacocks at Whipsnade.  We wrote a grant application to the to start the study together. This grant included provision to appoint field assistants for the breeding season and Carolyn Sanders acted as my most excellent assistant on the project. The paper was written after the field season and Carolyn was not involved with writing.  It is hard to recall exactly who wrote what, but looking through my files it looks like I produced a first draft which Tim then improved and added to. Tim is also a talented artist and drew all the lovely figures.


    HS: What is the history of the "free-ranging, feral population of blue peafowl at Whipsnade Park"? When were peafowl brought there and what for?

    MP: Whipsnade Park belongs to the Zoological Society of London, and I am afraid that I know very little about the history of the population of the peafowl, although it had been in existence for at least 40 years when I started working there. I know that peafowl born in captivity at London Zoo were brought to Whipsnade, and that Whipsnade provided a home for other peafowl from other sources. The keepers at Whipsnade sometimes caught and sold peacocks.  So my impression was that there were movements in and out of the population, and that this had been going on for some time.


    HS: Have you ever had the opportunity to observe peafowl in their natural range?

    MP: I have been to India twice for short filming trips during the peafowl mating season, and had the opportunity to watch peafowl there, although they were not ringed.  It was possible to observe a “lek” and courtship, and, although I didn’t see an actual mating, it was fairly easy to observe peacocks displaying close together in Sariska National Park. One of the aims of the filming trips was to film tigers and peafowl, so I also went to Ranthambore National Park. I can remember seeing peacocks in flight there…a fabulous sight!  Although I didn’t note any obvious differences in behaviour between Indian and UK birds, there was an obvious phenotypic difference: the peacocks in India tended to have longer legs, and, as a result, held their trains further up from the ground.


    HS: What was a typical day like when you were doing this work? Did you do the trapping and banding and lek observations yourself? Who was Nigella Hillgarth, who you acknowledge "for help in marking and measuring the birds"?

    MP: I don’t think I can describe one typical day because they would vary so much over the year. But some tasks would predominate at particular times of the year. I was heavily involved in catching birds in the months prior to the breeding season, and took all the measurements myself, whilst Nigella held the birds (to make sure the same person took all the measurements).  My memories of this was that it was very cold as we had a small unheated shed to work in, and under these adverse conditions, Nigella and I became great friends.  Sometimes we had large numbers of birds to process all at once, so we would work very long hours. At the time, Nigella was a PhD student working on pheasants in the Zoology Department in Oxford, and was her supervisor.  Nigella was interested in the ecto-parasites of peafowl, and as part of her work, we recorded the number of feather mites drinking at the eyes of the peafowl in a time period. Nigella and I are still in touch, and she is now the president and CEO of the .

    During the mating season, I was heavily involved in watching the birds. The lek watching started in mid-April and continued until the end of May; Tim and Carolyn also covered some of the watches.  The aim was to arrive at the lek early in the morning, before peacocks left their roost sites, and continue until the males stopped displaying, around the middle of the day. This could mean very early starts for me, as I was living in Norfolk at the time, and it was a 100 mile drive to the Park. We would watch from a small canvas hide, sitting on a small canvas chair, but sometimes we had to kneel to move round the hide, in order to follow females moving between males situated around the hide.  Watching the birds was extremely interesting and stimulating.  There was always something new to see, and many observations would make you ask ‘why are they doing that’? Some observations would provoke analyses that contributed to a paper.  An example of this was the observation that certain females would sit by particular males and engage them in courtship at times when another female tried to approach them.

    After the mating season I was involved in data analysis and writing up, preparing to give talks at summer conferences, applying for grants and jobs!  This went on until Christmas and then the cycle would begin again.


    HS: The observations ended in May 1988 and the paper was submitted on 8 July 1989. Can you give us a sense of what happened in the intervening one year?

    MP: Whilst the observational work ended in May 1988 for this paper, we were still working at Whipsnade. In April and May 1989, I had four field assistants and we watched at four leks within the park.  After the end of the observation season in 1988 there was a period of analysis and writing the paper first for Nature and then for Animal Behaviour.  The referees requested changes so the paper needed to be revised before it was eventually published in Animal Behaviour On a more personal note my second child was born on 1st August 1989.


    HS:  Was the term "hoot-dash" used for the first time in this paper? Is it still used when describing peafowl mating?

    MP: No, hoot-dash was in the literature and is still used as far as I know.


    HS: Was the photo in Fig. 2 of the "hoot-dash" taken in Whipsnade park? Was Chris Pierpoint a professional photographer?

    MP: Yes it was, and Chris was one of the four excellent field assistants working in 1989 and was a very good photographer.


    HS:  Did this paper have a smooth ride through the publication process? Was Animal Behaviour the first place you submitted it to?

    MP: We first submitted the paper to Nature but it was rejected, so we rewrote the paper for Animal BehaviourNature has a very strict word limit, so the first draft of the paper for Nature was a lot less expansive than the Animal Behaviour version. 


    HS: You acknowledge Morris Gosling and Robert Gibson for "comments on an earlier draft". Could you tell us who these people were and how you knew them?

    MP: and I worked together on Chinese Water Deer at Whipsnade and on lekking in Topi in Kenya.  He is also my long-suffering husband.  is a colleague who has done some outstanding work on mate choice and lekking in sage grouse.


    HS:  How did the collaboration with , for the female choice null model, come about?

    MP: I gave a talk at the Zoology department in Oxford and presented the data on the sequence of males and females visited.  Alan attended the talk, came up to me afterwards and kindly offered to analyse the data as it is now presented in the paper.


    HS: You say "a large part of the variance in mating success can be attributed to train morphology and that females choose to mate with those males that have the most elaborate trains of those sampled". You also say "Our data do not suggest that competition between males is an important determinant of mating success". Today, 25 years after the paper was published, do these statements still hold true for peacock mating behaviour?

     MP: I do think that there is good evidence for these statements from the data that we collected at that time.  Whether it is ‘true’ for all peafowl everywhere is a different question, and whilst some studies have found the same positive relationship between train morphology and mating success, at least claims that no such relationship exists (although, they did find a non-significant positive correlation).  Of course, if females do not prefer peacocks with elaborate trains it does raise the question of why the peacock’s train has evolved, and I haven’t seen any good data that support any alternative hypothesis.


    HS:  In the Discussion, you highlight many questions for future research - how females assess males, why do females choose males with more elaborate trains, what determines whether males obtain a display site, how do males choose leks - have these questions been addressed since? 

    MP: I do think we are further ahead with these questions:

    Why females choose males with more elaborate trains formed the basis of much of my future peacock work, after the publication of this paper.  I removed peacocks from Whipsnade and bred from them in captivity.  This was a controlled breeding experiment, where each Whipsnade cock was mated with 4 females, and the subsequent eggs removed from pens and artificially incubated and hatched in separate compartments, so we knew the sire for all the offspring produced.  The young were reared in large groups and monitored regularly to record growth.  When the offspring were old enough, they were released into Whipsnade Park and we observed their subsequent survival and future behavior. 

    We also followed the male offspring of the release experiment through to sexual maturity and looked at where males started to display.


    HS:  Your study was entirely observational and with a small sample size (N = 10 males). Since this study, have you had the opportunity to repeat these tests with larger sample sizes and in an experimental way?

    MP: Yes, I looked at the relationship between train elaboration and mating success in a much bigger sample from four lek sites.  I have also removed eye spots of peacocks and shown a change (reduction) in subsequent mating success.  but this has not been cited nearly as widely as the Animal Behaviour paper. 


    HS:  Did this paper create a buzz - within academia and outside - when it was published?

    MP: My memory is that there wasn’t a huge amount of buzz around this paper, although it did get some attention. Other papers that I have published created a bigger response in the media, such as showing evidence for improved growth and survival of the offspring of males with more elaborate trains.


    HS: How important has this paper been in your career? Has it had a major influence on the course of your future research?

    MP: I think that the peacock work has had a huge impact on my career and it was certainly critical in my obtaining a NERC advanced research fellowship which I held in Zoology at Oxford and which provided the wherewithal to do a further 5 years of pure research.


    HS: Have you ever gone back and read this paper after it was published? When you read this paper now, what are the aspects about it that strike you first?

    MP: I did have a look at the paper again recently, in response to your questions, and it does seem like something from a different era, where natural history and simple field observations were considered to be important.  Times have changed enormously in academia, and it is now extremely difficult to obtain money to do this sort of work.  This is a shame, to say the least, as there is so much that we don’t know about the natural world.


    HS:  If you compare this paper to papers you write today, are there any differences, e.g. in writing style?

    MP: I am not sure how my writing style has changed, if it has at all, but how you produce papers has changed.

    As you become more senior in academia your job changes from being one where you do everything yourself (from collecting data to analyzing and writing papers) to one where you spend a lot of time applying for grants for other people to work as part of a team.  Your job becomes contributing ideas, reading other people’s work and contributing to that, rather than writing your own papers from scratch.


    HS: Have you had the opportunity to go back to your study site after the paper was published? Are any of the birds you banded still around?

     MP: I wrote a number of papers on peacocks after this one was published in 1991, and this involved doing several years more field work at Whipsnade. However, in 1996, I moved to a new post at Newcastle University, and once I moved to the North-East, it was logistically difficult to continue working at Whipsnade.  I continued to work on peacocks at a peacock farm in Norfolk.  I have been back to Whipsnade once, a few years ago, and saw very few peafowl.  Apparently, there was a big cull when there was an avian flu scare in the UK, as the keepers were worried that avian flu could be passed from the free-ranging peafowl to other animals in their collection.  I saw one of my marked birds, and it was begging at one of the restaurants in the park.  Flint pit paddock still exists, but it is no longer full of peacocks.


    HS:  This paper has been cited 360 times (Google scholar) as of today. Do you keep track of these citations, and do you know what this paper gets cited for, mostly?

    MP: I do not look at the citations of this paper very closely nowadays, but think it is usually cited as evidence for female choice. Although this is not universal, and in my experience, what people actually cite in a paper sometimes has more to do with what they are trying to say, than what you have actually said!


    HS: What would you tell a student who is about to read this paper today? Any caveats? What should he or she takeaway from it?

    MP: Probably the most important parts of the paper are the data on individual females.  These show two things: one is that females don’t mate with the first male that they approach; they always look at more than one male and this is very good evidence for female choosiness.  The second is that they mate with the male that has the highest eye-spot number of those visited.   This suggests that the male’s train has something to do with their choice, although it is not necessarily eye-spot number that is being assessed, and it may be something that is related to eye-spot number. It may also explain why males with relatively few eye-spots obtain matings (by being the best of those sampled), and that this doesn’t always result in a high correlation between train characteristics and mating success either within a lek or across several leks.


    HS: Among all the papers you have written, is this your favourite?

    MP: I wouldn't say that this paper is my favourite. The first paper I wrote from my PhD work will always have a special place in my heart and that iswhich was published in Science in 1983.







Powered by Drupal | Theme modified by Naupaka Zimmerman from Danland by Danetsoft | | INNGE is supported through a collaboration with INTECOL