Adult beetles were fed aphids from genetically identical asexual aphid lineages harboring either the facultative symbiont S. symbiotica (aphid line 5AR), the facultative symbiont H. defensa (aphid line 5AT), or no facultative symbiont (aphid line 5AO).
For the purposes of this investigation, a species is considered hydrophytic if its probability of occurring in an aquatic and/or wetland system is 67%% or greater (i.e. designated as either a facultative- or an obligate-wetland plant by the United States Fish and Wildlife Service; Reed 1988).
Accordingly, tumor-colonizing bacteria are either obligate or facultative anaerobic.
Some of them are associated with accessible chromatin, others with heterochromatin, either constitutive or facultative [1].
Some of them are associated with accessible, active chromatin, others with heterochromatin, either constitutive or facultative [1], [2].
Thelytoky can either be obligate or facultative [ 4]; males are generally absent in obligately thelytokous populations, with the exception of the rare production of males [ 1].
Although semelparity is a life history characterized by a single reproductive episode within a single reproductive season, some semelparous organisms facultatively express a second bout of reproduction, either in a subsequent season ("facultative iteroparity") or later within the same season as the primary bout ("secondary reproduction").
These symbionts can be classified as either obligate or facultative for host survival.
Our overall findings are in agreement with previous studies utilizing experimental cellular models of bacterial internalization, using either intracellular or facultative intracellular pathogens.
On the mechanistic side, we begin by asking whether its higher representation in spores is due to either fixed or facultative allocation strategies [ 34].
