it is important to recognize that organisms within a population may not always have the same strategy, and different strategies may offer individuals either a range of tactical options or just one tactic. furthermore, given strategy may be considered mendelian, developmental, conditional, or a combination of the above. a mendelian strategy depends on a genetically determined phenotypic difference, such as body size. this is the case in marine isopods, described below. developmentally driven strategies are associated with phenotypic differences caused by varying conditions during the course of development that affect body size or overall adult health. individuals may also have a conditional behaviour strategy that depends not on the genetic or developmental impact on one's life circumstance, but on external factors. these may include the number of available mates, or the number of nearby competitors and their employed tactics. additionally, some mating strategies will be impacted by the interaction of multiple factors, so these categorizations of mendelian, developmental, and conditional are not mutually exclusive. they simply offer ways to think about alternative mating strategies and their root causes.