Particularly, given the strongly localised dispersal of S. hystrix [ 26], the selection-driven partitioning of ecotypes across habitats would result in assortative mating (i.e., mating with neighbours), which may drive and/or strengthen the genetic divergence of the depth-associated populations.
When we fix the proboscis length of pollinators (proboscis length is assigned to individuals at random, independently of the proboscis length of their parents, using the same probability distribution at each generation), there is absolutely no divergence in the depth of corolla tubes following 10000 generations (Fig. 4A).
By contrast, increasing the divergence of the illumination decreases the depth of focus and allows more flexibility regarding the cleanliness and quality of the illumination path.
Ingram [ 10] showed evidence that rockfish speciation is associated with the divergence of habitat depth and depth-related morphology, which supports that this group of fishes are undergoing ecological speciation along an environmental gradient.
Increasing the number of "pollen parcels" from two to ten, while keeping all other parameter values fixed, interferes with the divergence of corolla depths between the two plant species.
Reducing the lifespan of flowers to one tenth of the baseline value, so that the average number of visits per flower is reduced from 20 to 2, leads to a further decrease in the divergence of corolla-tube depth (0.24±0.08 units).
However, it is important to notice that the positioning of the FOV using a single projection is prone to error because of the summing of attenuation structures in the depth direction and divergence of the beam [23].
Mitochondrial introgression does not misled phylogenetic inferences at the depth of the divergence of the avian radiation and the range of mutation rates among mitochondrial genes make this an excellent single loci to study.
In this paper, we extend the model of Rodríguez-Gironés and Santamaría [16] to study the conditions under which, if the two pollinator species have originally the same tongue length, natural selection can lead to the simultaneous divergence of corolla-tube depth and tongue length.
However, for more in-depth interpretations of the remarkable divergence of the Philippine population, a broader geographic coverage of the whole island group would be required.
If pollinators specialised on flowers with deep corolla tubes became inefficient at exploiting flowers with shallow corolla tubes, divergence of corolla-tube depth would indeed promote flower constancy.
