“I think it’s maybe hard for you to realise that, up until the ‘60s, animal people studied animals and plant people studied plants. Very few people tried to study the interactions between them because you had to learn two different worlds. Remember, we used to have botany departments and entomology departments and zoology departments. Three separate administrative castles. Each one of them with their own purpose, their own rules and own awards, their own students, their own budgets. When I was in the entomology department, it was viewed as not good if I went to seminars in the botany department!”

“I think it’s quite a self-contained piece. Maybe it will be good to read it together with the 2003 review. And then, of course, you know, nowadays there are much later and kind of like more up-to-date reviews of work that obviously couldn’t exist back then. But I still think that people tend to think that it makes a point that can be understood, by reading it just like that.”

“I think most of what we said still stands.”

“I think students today must see the paper in context. This was the very first attempt to see if stable isotopes could be used to model whole complex food webs. Before this paper, there really was no straightforward modeling of food webs using stable isotopes. All new and original and aimed at the “big picture” or overview. As I indicate below, technology at the time was also not what it is today and so sample sizes were often limited. Students have a much more convenient means of using stable isotopes in their research today. I would also say that the approach was not without its risks of failure and so it can pay to take chances in planning research questions.”

“I think that ours is certainly not the full explanation; I don’t think it is the full story. I find it hard to believe that if a bee flies, for example, distances greater than 10 kilometres in search of food, it relies purely on optic flow. It must feel tired, it must feel exhausted, its crop would be almost empty, and it would feel a sense of fatigue – all these would also indicate distance in some way, I think. Maybe for short to medium flights, optic flow is the only cue, but for longer flights I think other cues will be required.”

“I think that paper was definitely a product of its time context. And so, there are pretty clear references in there to different processes of speciation – vicariant speciation versus ecological speciation. I think, sometimes that, those debates, which were very current at the time, may not be so current now. So, it’d be very useful for somebody reading this paper, to be familiar with, you know, what the cladistic biogeographic school was doing and what the Endler Group, which was pushing ecological speciation at that time, was doing. It would help to have that context of what were the big issues and the big discussions at that time. That would be the main point.”

“I think that some of the main messages that are in my paper are all over the literature today. So from that perspective, if you are a student reading it, I don’t think you will be so surprised by it, because you are also reading it in so many other papers today. Of course, the newer papers also have more data and more sophisticated analysis.”

“I think that the bar to getting such a paper in a scientific journal is higher now, as it should be, given all of the complicating factors that have been studied since. I did that work in the early 80s. People worry much more about the size of the eggs, the scent of the eggs, the impact of having people check the nests, placement of the nests, as well they should.”

“I think that this 1983 paper does tell a story as it happened in a good historical context. It came out at a time that was really exciting. We published a more extensive follow-up cheetah study in Science in 1985 (227:1424) which is complementary. Interesting to me was that in the same 1985 issue of Science, right next to our cheetah study was the first description of the BLAST algorithm, written by David Lipman, soon to become the founding director of the National Center for Biological information – NCBI – which hosts the GenBank database. Lippman’s BLAST algorithm was like back to back with our study. We laugh about that whenever we get together, about how young we were and how important those two papers were. Time passes.”

“I think that this conclusion has stood the test of time in this system and in others. Andre Kessler and Ian Baldwin were somewhat skeptical of the result and repeated the basic experiment using a different sagebrush subspecies and wild tobacco in Utah. Their findings confirmed our results and added priming as a mechanism that we were not aware of. More recently, I conducted a meta-analysis with Louie Yang and Kyle Edwards of published and unpublished studies that examined volatile communication between plants of other species. This meta-analysis revealed that communication resulting in induced resistance is a widespread phenomenon, although it was not found in all systems. I believe that plants are under strong selection to evaluate their risk of being eaten. The most reliable cue of future herbivory is probably direct damage to the plant and this is the cue that has been described most commonly in studies of induced resistance. In addition to direct damage, many plants perceive volatile cues that are emitted by neighboring tissues of the same individual or neighboring individuals; to the extent that these cues provide reliable information about future risk, plants will be selected to respond to them. However, volatiles are not the only cues that can be perceived and offer reliable information.”

“I think that’s the main takeaway, but I think associated with that is the idea, which was novel at the time, that this was a consequence of inevitable correlations between the capacity to roar and your muscle condition and strength. So, it’s not purely just an observational paper that suggests that animals are competing by roaring. It’s also associated with ideas as to why this should be the case. And I would think that both of those hold.”

“I think the biggest disclaimer is not to take the paradigms too seriously and to think about other ways of thinking about the processes involved rather than the cartoons that are in that paper.”

“I think the core of this paper still holds, but how strongly so and whether it can really do so on its own, to the point that we get truly distinct species, is unknown. So, I think the paper is correct in terms of natural selection is part of the puzzle for understanding speciation, but the caveat would be that, I think it’s still unknown, in this system and in most systems actually, how far natural selection, on its own, can really push things. That would be the caveat. And that’s why, I guess, 15 years later, I’m happy I didn’t put ‘speciation’ in the title and that I used ‘reproductive isolation’ instead.”

“I think the most exciting studies are ones that show where it does and where it does not happen. In other words, just showing that it does happen someplace else is great. But I’m, in many ways, more interested in the ones that show that it does not happen, and wondering why is that. You know, what are the other things that are important? And even better are studies that perform these sorts of things in multiple locations, or under multiple types of conditions, and find that, well, in this area, it looks like it’s sort of confirmed,while in this area it looks like it’s not confirmed. Those sorts of multifactorial studies are very challenging to conduct, especially with diversity, because there are a lot of treatments involved. But I think those can be pretty powerful.”

“I think the one part that I would have changed, that I was the most uncomfortable with, was the section on remixing and gene flow and maladaptation. I felt that that was a little too speculative. Subsequent work supports all the other parts quite well, but I probably shouldn’t have included that part. But it was my attempt to address all the components of the geographic mosaic. I cringed when I read it.”

“I think the only caveat I would add is that the circumstances under which we did our tests on females in sound attenuating chambers with males is very unnatural. And that it would be better to try to show it in the flock setting where there are more males and females present. We stopped doing work inside attenuating chambers because it just seemed like not a very good environment for the birds. I mean, the chambers are very large and they had a lot of room to fly and things like that, but it still isn’t the same as an outdoor facility, where the birds can decide who they want to be with and form groups of their own volition. We were forcing males and females together, and I think I would rather have them try to connect naturally. So that’s what I would say.”

“I think the paper is now remembered as representing the formal birth of the field of phylogeography. Of course, I couldn’t have fully anticipated this at the time, but I did certainly have a sense that it had the potential to become a landmark treatise.”

“I think the paper stands as it is. There is nothing I regret or where I think the results are not right. Work with other parasites of Daphnia done in my group are largely consistent with the first results. Studies in other systems also largely confirmed that the overall conclusion is sound. However, we know now that in some systems the story is much more complex. Maybe I was lucky that in my system the outcome was rather clear cut.”

“I think the results hold, and that’s nice to be able to say. My sense is that they were preliminary experiments, but due to my own work on radish for a couple years after that, as well as work other people have done in other systems, this seems to be a general phenomenon.”

“I think the story itself was solid. The data were solid. Although the sequence data was just mitochondrial, I also had allozyme data which told a similar story in terms of evolutionary relationships. And allozyme data provide fairly good nuclear markers that at least give you more confidence than mitochondrial DNA alone. I mean, given what was available at the time, the data were really not bad at all. I mean if I did it now, of course, they’d say, “Oh, we want far more markers”, and allozymes went out with the dinosaurs! But it’s kind of silly that people abandoned allozymes, to be honest, because they were great markers and there was minimal fuss and bother. It was easy enough to just get them, and as long as you had enough of them they provided a pretty good indication of relationships.”