Virtually every theoretical model about competition that I can think of models exploitation competition. As I write this, I’m watching three hummingbirds outside chase each other away from the feeder, where none of the resource is being consumed. For most non-ecologists, interference competition is how they envision competition between species, so it’s surprising that it’s been given so little attention in the ecological literature. Thus, I was excited to read this manuscript from Grether and Okamoto that incorporates both forms of competition. By incorporating evolution into their ecological model, they find increased coexistence between species when a superior interference competitor evolutionarily tracks a superior exploitative competitor. One take-away from these results is that exploitation is more important for competitor coexistence than interference competition and so the theoreticians have it right in terms of choosing to focus on this process. However, as ecologists continue to appreciate the value of evolution on short time scale in altering ecological outcomes, eco-evo models such as this one are becoming more common. This one suggests that in an eco-evolutionary scenario, failing to account for interference competition would drastically underestimate the region of parameter space in which competitors can coexist.

I think that is manuscript is likely to result in a publication in Ecology Letters eventually, although I think it deserves some clarification in a number of places. I don’t suspect that these clarifications will result in any fatal flaws, but will help readers to better understand the logical reasoning behind some of the results and assumptions. I found myself having to explain things out loud to myself in various parts and I ultimately was able to understand these difficulties, but some more clarity would help. Thus I present this list of places where clarity could be improved or assumptions made clear:

Line 44-45: after reading the manuscript, why a superior interference competitor would go extinct makes sense, but in the abstract, why one would ask this question at all is counterintuitive. So either this needs some more explanation in the Abstract, or to be worded differently.

Line 57: Briefly explain how microbes engage in interference competition.

Line 67: explain why a superior competitor would go extinct because this is counterintuitive.

Line 118: I think this assumes that the superior interference competitor must also be an inferior exploitative competitor, but make this clear

Line 130 and elsewhere: I was initially confused by this because I was focused on the importance of interspecific competition. But this model relies on the assumption that intraspecific competition is greater than interspecific competition and that heterospecifics are more easily recognized as competitors when they are phenotypically closer to conspecifics. The whole model depends on this assumption because otherwise I assume you would see very different outcomes. I think that’s a perfectly valid assumption (and one that most competition models also make), but just make it clear and provide justification for the assumption…but also I think that will help the reader understand this logic.

Line 165: What are the four traits? I agree that the phenotypic cue and fighting ability are two traits. Yes, u and s play into how the phenotypic cue is perceived, but these aren't individual traits, but population-level traits.

Line 178-180: is there still some stochasticity in who wins the interaction, or does the better fighter always win? I’m assuming there is some chance involved in who wins, but the role of stochasticity decreases with increasing differences in fighting ability. Please clarify.

Line 184-185: Say more about how nestling survival is related to exploitative competitive ability

Line 189: “more likely to lose” might be better here

Line 214: “intraspecific territoriality is not assumed by the model”. Just to make sure I understand this correctly, this is not assumed, but there IS a critical assumption that similarity = territorial response, which makes sense because it's hard to imagine a scenario in which intraspecific similarity is lower than interspecific similarity

Line 216: Change “While” to “Although”

Line 230: Many would say that this is co-occurrence, rather than coexistence, which is defined by the ability to increase when rare. I find that definition very strict, as co-occurrence for 900 generations seems plenty relevant to an ecological scenario. In this model though, when do species go "extinct"? When < 1 individual? Or does it take a very long time for extinction to occur, despite a species being effectively extinct? What percentage of these cases of coexistence involve both species at relevant abundances in nature?

Line 231: Why only for these cases? Couldn't evolution also be important in one or both spp going extinct over shorter time frames?

Line 233: Why only for these cases? Couldn't evolution also be important in one or both spp going extinct over shorter time frames?