The gesturing towards the infected wolves being more reproductively fit in general is probably wrong, however. Of course wolves can be more aggressive if it’s actually a good idea, there’s no need for a parasite to force them to be more aggressive; the suggestion about American lions going extinct is absurd − 11,000 years is more than enough time for wolves to recalibrate such a very heritable trait if it’s so fitness-linked! So the question there is merely what is going on? Some sort of bias or very localized fitness benefit?
Is there a selection bias whereas ex ante going for pack leader is a terrible idea, but ex post conditional on victory (rather than death/expulsion) it looks good? Well, this claims to be longitudinal and not find the sorts of correlations you’d expect from a survivorship. What else?
Looking it over, the sampling frame 1995-2020 itself is suspect: starting in 1995. Why did it start then? Well, that’s when the wolves came back (very briefly mentioned in the article). The wolf population expanded rapidly 5-fold, and continues to oscillate a lot as packs rise and fold (ranging 8-14) and because of overall mortality/randomness on a small base (a pack is only like 10-20 wolves of all ages, so you can see why there would be a lot of volatility and problems with hard constraints like lower bounds):
Wolf population declines, when they occur, result from “intraspecific strife,” food stress, mange, canine distemper, legal hunting of wolves in areas outside the park (for sport or for livestock protection) and in one case in 2009, lethal removal by park officials of a human-habituated wolf.[21]
So, we have at least two good possible explanations there: (a) it was genuinely reproductively-fit to take more risks than the basal wolf, but only because they were expanding into a completely-wolf-empty park and surrounding environs, and the pack-leader GLM they use doesn’t include any variables for time period, so on reanalysis, we would find that the leader-effect has been fading out since 1995; and (b) this effect still exists, and risk-seeking individuals do form new packs and are more fit… but only temporarily because they occupied a low-quality pack niche and it goes extinct or does badly enough that they would’ve done better to stay in the original pack, and this wouldn’t show up in a naive individual-level GLM like theirs, you would have to do more careful tracing of genealogies to notice that the new-pack lineages underperform.
The gesturing towards the infected wolves being more reproductively fit in general is probably wrong, however. Of course wolves can be more aggressive if it’s actually a good idea, there’s no need for a parasite to force them to be more aggressive; the suggestion about American lions going extinct is absurd − 11,000 years is more than enough time for wolves to recalibrate such a very heritable trait if it’s so fitness-linked! So the question there is merely what is going on? Some sort of bias or very localized fitness benefit?
Is there a selection bias whereas ex ante going for pack leader is a terrible idea, but ex post conditional on victory (rather than death/expulsion) it looks good? Well, this claims to be longitudinal and not find the sorts of correlations you’d expect from a survivorship. What else?
Looking it over, the sampling frame 1995-2020 itself is suspect: starting in 1995. Why did it start then? Well, that’s when the wolves came back (very briefly mentioned in the article). The wolf population expanded rapidly 5-fold, and continues to oscillate a lot as packs rise and fold (ranging 8-14) and because of overall mortality/randomness on a small base (a pack is only like 10-20 wolves of all ages, so you can see why there would be a lot of volatility and problems with hard constraints like lower bounds):
So, we have at least two good possible explanations there: (a) it was genuinely reproductively-fit to take more risks than the basal wolf, but only because they were expanding into a completely-wolf-empty park and surrounding environs, and the pack-leader GLM they use doesn’t include any variables for time period, so on reanalysis, we would find that the leader-effect has been fading out since 1995; and (b) this effect still exists, and risk-seeking individuals do form new packs and are more fit… but only temporarily because they occupied a low-quality pack niche and it goes extinct or does badly enough that they would’ve done better to stay in the original pack, and this wouldn’t show up in a naive individual-level GLM like theirs, you would have to do more careful tracing of genealogies to notice that the new-pack lineages underperform.