The phrase "a certain morph" is correct and usable in written English.
It can be used in contexts discussing specific types or forms of something, particularly in fields like biology, linguistics, or art.
Example: "In this study, we will focus on a certain morph of the species that exhibits unique characteristics."
Alternatives: "a specific morph" or "a particular morph".
In addition, although there is suggestive evidence that male preference for a certain female morph depends on the previous experience with that female morph e.g. [ 27], the role of innate male mating preferences and ontogenetic changes in male preference have until now received little attention [ 28].
The overall high neutral FST-value for this lizard species (0.208) should, however, increase our statistical power to detect stabilizing selection in this system that might have favored a certain stable morph frequency equilibrium in all populations.
An obvious suggestion is that divergent selection or gene-by-environment interactions [ 45] affect the precise equilibrium, favouring certain morphs under a given set of ecological conditions such as particular densities of con- and heterospecific damselflies, differences in climate, predation rate or parasite load among populations.
Even when potential fitness in a given population differs between morphs, polymorphism is protected in the population if the advantage of fitness potential of certain morphs is countered by frequency-dependent disadvantage (common morph disadvantage).
On the boundary between each phase, disadvantage in the fitness potential of certain morphs is countered by rare morph advantage when its frequency is juts zero.
Given that discrete colour morphs are often genetically correlated with other traits such as behaviour, physiology and life-history, selection may act on these correlated traits which make certain morphs better adapted to different environments.
Furthermore, transitions towards heteroecy necessitate changes in the ability to produce certain morphs (heteroecious species must necessarily produce winged males, while some of the monoecious Brachycaudus produced unwinged males only [ 14]) as well as changes in host preference for Prunus in several morphs (winged males and gynoparae).
"In terms of policing it, in terms of trying to prevent these acts, they kind of morph to a certain extent," Mr. Kelly said.
In contrast, NFDS led to the coexistence of two morphs with different potential fitness in a certain geographic range along latitude due to rare morph advantage, and resulted in a smooth geographic cline of morph frequency.
On the other hand, NFDS that is independent from the potential fitness may counteract a certain amount of difference in the morph specific potential fitness.
