Hi Paul,
Those are all good questions. To some, I don't think we have any answers yet. I'll do my best to summarize my understanding:
Mol_PMB wrote: ↑17 Apr 2019, 16:08Where these live together in the wild, is there evidence that one evolved to mimic the other, or simply that both species evolved to be well camouflaged in the local environment?
This is a tough one to answer. The latter option is perfectly reasonable and may be sufficient to explain a lot of pattern similarity, but it wouldn't exclude an influence of the first idea. Also, there's no reason to discount the possibility that one idea may be the cause and the second occurs serendipidously.
Mol_PMB wrote: ↑17 Apr 2019, 16:08Where similar-coloured species don’t live together, can this be considered mimicry at all?
No, I don't think mimicry would apply to species living in different locations, unless perhaps they are dealing with predators that are able to hunt both species (e.g., a migrating or wide-ranging predator). Taking into account my comment above, it's also been my impression that in many fish (in particular, we'll focus on corys and plecos here), I've noticed that certain genera and lineages seem to have above-the-species-level color patterns which I infer are genetic traits of the group, and this may pre-dispose fish that have shared ancestry to develop similar color patterns. What do I mean by this? Take a look at the
or
or
- there are certain color patterns which prevail in the genus (e.g., the scrolled lines on the face of many
Panaqolus) which do not occur on plecos of other genera. Likewise, the black & white colors of many hypans are not recreated in
Ancistrus or
Panaqolus or other genera. These genetically determined patterns seem to be arch-typical of subgroups within each genus. In that sense, I am not surprised to see the re-occurrence of patterns like those of
,
or
in a variety of cory species, even if they don't live side-by-side. So is that mimicry or merely relatedness? Even if it is relatedness, it does not exclude any benefits of mimicry (but as you point out, if the two species do not live together, it's difficult to call the color match "mimicry" since, what are they mimicking?)
Mol_PMB wrote: ↑17 Apr 2019, 16:08Also I note that there are several examples of mimicry with other species (including Brachyrhamdia and some characins). With the elegans group having different habits (more mid-water dwelling than most corydoras) should you perhaps be looking for a characin mimic?
True, you might expect that, but I'm asking about mimicry within the corys between different lineages. I suppose you could argue that all of the corys WITHIN the
group are mimicking each other, but I'm thinking about all the corys that have mimics in other lineages. Perhaps because the
elegans group species tend to be midwater swimmers and most other lineages of corys are not, that might predispose them to NOT mimicking the
elegans-type corys. If that were the single explanation, I would find that fascinating.
Of note, @The.Dark.One observed that
can resemble some of the females in the
elegans group. This is true. I was thinking of male
elegans types when I asked my question, but the female comment should not be overlooked.
Cheers, Eric
