“I would say it’s just a small study that illustrated a particular point. And it’s not the last word on the subject by any means. There’s still a lot of analysis to be done. And many other systems and the conservation angle are still out there to be explored. I guess I’d say that.”

“I would say that the questions asked in that paper remain relevant, but the approaches needed to answer them will need to be more multifaceted compared to what I did. We need descriptive work, experimental work, and modelling in order to understand the structure and functioning of trophic networks.”

“I would say the statisticians have not shaped up at all. And I think that applies to the professional statisticians who teach statistics as well as other scientists who also often are teaching stat courses – biologists, psychologists, so on. The stat books, including some of those most commonly used by biologists, often completely ignore design. And that’s a major flaw in Sokal & Rohlf, probably the single biggest flaw of many that are in that book. I’m not sure if I published this or just commented on it, but there is a basic problem in the interaction between statisticians and people in other disciplines: statisticians often have a professional interest and professional incentives to develop fancy new methods for very special case type situations, and have no incentive to try to help people stop making simple errors in papers. They think that’s a little bit below them. And they’re not interested, they don’t enjoy reading critical reviews of statistical practice, like the sorts of things I’ve written. The editors often have a hard time because the statisticians are saying, “Well, yeah, these ecologists are making all these stupid mistakes, and that’s what Hurlbert’s talking about in this paper, but you know, they should clean up their own mess. You don’t need statisticians in order to avoid pseudoreplication.” Or, something of that sort. So the books remain not very good.”

“I would suggest to read it together with some of the key papers that followed in this field, because by putting it into a historical perspective you get a better idea how science really works. There is a tendency nowadays to lament about the fact that science is not reproducible. There are certainly some important issues that are worth discussing in this context, but part of the discussion bores me because it seems to be based either on false ideas about how science actually works or on unrealistic ideas about how it should work. There is no such thing as a perfect study. Studies are always done in a particular context and not always will the results be generalizable across contexts. That is especially true in our field, where we are working within a complex and variable ecological context. I think it is important that students learn, at the earliest possible stage, that science is not about writing the definitive paper on a particular issue, and that research is not about going in a straight line from point A to B. I like the way Stuart Firestein puts it, in his wonderful little book “Ignorance: How it Drives Science”: science is like “looking for a black cat in a dark room without knowing that there is a cat in the room”. So, it’s about being curious about a phenomenon and studying it from this or that angle, through careful observations or experiments. It’s about drawing conclusions that seem most reasonable given your data as well as your knowledge and thoughts and those of others at that time. And it’s about admitting limitations or weaknesses and openly discussing things we still do not know. Things are rarely black-and-white. Coming back to the evolution of extra-pair paternity, there is still evidence in some systems pointing to genetic benefits, but there are also studies that suggest that female extra-pair behaviour might even have evolved in the absence of benefits, simply because of strong selection on male extra-pair behaviour. There is no simple answer, and it remains interesting, so if a student is interested, he or she can still go out there and discover a black cat, or perhaps it will turn out to be a blue bird.”

“I would tell her that this paper is very difficult to read, but it has a lot of interesting information that might be useful to her. I would explain the value of story telling as a means of understanding nature, and that there are several interesting stories in the paper. I would suggest that as she reads it she copies the table of contents and lists the various vignettes or stories in the paper, and at the end see if she can synthesize those that are of interest to her into a big pictures story that makes sense.”

“I’d say: Come with me into the woods, watch these butterflies displaying, think of the sorts of questions you would ask, think critically about whether the experiments I did provided convincing evidence [] and then think critically about whether the interpretation I gave from the current theory at the time would be a useful interpretation today.”

“I’m actually trying to figure out a schedule to go down there for a month, with some help, and do a 50-year census. I think it will be interesting and historical. I’m in good physical shape, so I’m going to try to do it, somehow.”

“If I said that, it represents another terrible omission. Most of the focus of the paper and my career is on the various evolutionary roles of biological interactions: competition for potentially limited resources, predation, disturbance, and facilitative interactions. Certainly those three factors are critically important, but I would also add biological interactions!”

“In retrospect, I think I, too, jumped on this interpretation too quickly.”

“In terms of the main conclusions, yes, I think so. The question is, what else is involved, because clearly something else is involved. We ran several other experiments looking at alternative factors that might affect the evolution of discrete morphs. [...] And the answer was that behavioral factors did not work either. There’s clearly something that has to happen at the genetic level that predisposes moths to form discrete morphs. We were not able to access it. So, we did not have the final answer. And that’s not exactly unusual in science. I don’t feel disappointed with the work at all.”

“it [paper's conclusion] doesn’t only hold true; it has become, let’s say, a common sense. At that time we wrote that this maybe a unique rapid micro-evolutionary process that we have observed. Since then we have come to learn from many other papers, many other plants and animals, that this is not an exception. This is normal. But it was absolutely overlooked before we did this experiment. You may have heard about Peter and Rosemary Grant from America, from the Princeton University. They have worked for decades on the Galapagos Islands. They were astonished when, once, after a big drought, a specific population of ground finches went almost extinct, but after a while started to not only survive but also to increase the population again. This was due to the fact that they had developed, in a very short time, extremely strong beaks with which they could open the only seeds that could be harvested in the extreme drought. And when the normal climatic conditions came back to the Galapagos the size of the bill was again reduced to normal size. All this happened within about 10 generations. We have so many more examples – e.g. snakes that lay one more egg in a clutch and so on. And all this can happen within a few generations, in about 10 years or so. So this is now a general biological aspect. Therefore, I would say, the paper opened an area of understanding of how rapid and effective evolution can work everywhere in the world.”

“It is certainly one of the most important in the sense of its impact on the field and in clarifying, to myself, my thinking about Community Ecology. It has been gratifying to the extent that Community Ecology has encompassed the points of view expressed in the paper, although I believe this would have happened in any event. Thus, the paper was perhaps more a chronicle of changes ongoing in Community Ecology at the time.”

“It was a paper that marked my transition from being an ecologist to being a conservation biologist. I might have called myself a conservation biologist when I wrote this paper, but only just. Soon thereafter, I would say – I’m a conservation biologist.”

“It would be interesting to revisit and update it and to broaden it to include more recent work on functional diversity, phylogenetic diversity and a lot more island material, and to make a serious effort to expand to more explicitly include aquatic and especially marine systems, but that sort of synthesis would probably require a monograph to do it justice.”

“It’s still really relevant today. But of course, there is this big big chunk missing, which is: why birds in high conditions should breed earlier or be bigger or have longer tails. A lot of unfinished work. So if you are reading this paper today, make sure you understand why heritable traits don’t evolve, and then go back to the literature of the last 30 years to understand why condition correlates with these traits.”

“Its main findings have been remarkably robust. For instance, we had another debate after the first one, with Brad Cardinale and others who published a review paper in Nature in 2006. Their paper suggested again that biodiversity effects in experiments were largely driven by the sampling effect. Andy and I didn’t agree on their conclusions, but instead of fighting against each other, we decided to work together to perform a meta-analysis of all the grassland experiments that had the appropriate data. That joint work was published in PNAS in 2007. Andy and I were convinced that complementarity was important even in their data based on our previous experience. Brad and others were convinced that this was not the case. So we decided to analyse the data together using our method. It took one year for Brad to accept that we were right but in the end he did, which I view as a valuable sign of scientific honesty. Now we have more and more examples showing that complementarity is the leading factor in biodiversity experiments, so the conclusions of our paper hold more than ever. Our method does not solve everything, it has some limitations, some of which are even mentioned in the paper. But overall I would say that both the method and the results of our paper have stood the test of time particularly well.”

“Jeremy [Jackson] has told me that, when he was at Yale as a graduate student, he thought our ’72 paper was all wrong; absolutely wrong. And that there are examples that we gave in that paper that were not convincing or were not really well analyzed; not really scientifically done. So, years later, he comes along and he looks at the bryozoans that are alive, he’s doing some molecular stuff with them, and working with Alan Chatham, a palaeontologist, going down the last 20 million years to look at these lineages of these species that are still alive today. And he says, you guys are absolutely dead right. And I said, what about the turnovers and, you know, do things happen more-or-less across lineages at about the same time? He said, absolutely. So, I always go to Jeremy’s paper. I just tell people read Jeremy, because he was a profound doubter, he did the work at the level that he thought we should have done our work at, and he found out that we were dead right. And had the honesty and courage to publish it.”

“Keep in mind that this was one of the first phylogenetic studies – and certainly the first in comparative physiology – that made an explicit attempt to look at the evolutionary patterns of multiple quantitative traits for a clade of organisms. In that sense, it was pioneering, but the methods we used certainly don’t approach contemporary standards, and the phylogeny available to us at the time was very crude. Even so, the fundamental co-evolutionary questions we asked are still valid and are still interesting to those interested in evolutionary physiology.”

“Maybe a way to ask that question is, what would be a better paper to recommend than this one, if you had to read one paper in this field? And I’m not sure what that would be. And this is embarrassing because I do teach undergraduates and so I should be able to say, here’s what you should read if you want to get introduced to this field.”

“My views have shifted a bit. I think what that paper did get right is mating preferences can evolve for non-adaptive reasons. It is mentioned in that paper that almost certainly any gene that affects a mating preference is going to have pleiotropic effects, perhaps on things not having to do with mating at all. Every mutation, every allele that has a phenotypic effect has pleiotropic effects. It’s almost inevitable that those pleiotropic effects can have some influence on how the mating preference evolves. So I do think that there are a lot of “mating preferences” - female biases – that are responsible for the evolution of extremely elaborate male traits, that are there for reasons completely disconnected with mating. That much I think is correct. In this paper, and in some later papers, I was probably a little bit too militant about arguing against the so-called ‘good genes’ or indirect benefits. Much after this paper, I worked on the reinforcement of mating preferences, when you have two species that are hybridizing and producing low-fitness offspring. This is an idea that goes back to Dobzhansky. When you have that situation, you can have reinforcement of mating preferences that strengthen barriers and decrease the amount of hybridization. [...] And if you believe that reinforcement works, then you believe in indirect benefits, because reinforcement of mating preferences during hybridization is basically an extreme version of ‘good genes’. If you think about mating with a heterospecific as being a really bad genetic choice, that’s just an exaggerated version of picking a really bad male of your own species. So, it’s really a matter of degree. I’m more open, I think, now to the possibility of genetic benefits, not just with reinforcement of hybridization between species, but with conspecifics as well. So, yeah, maybe I’m getting old and soft, but I’m more open to that being a viable hypothesis than I was.”