it can sometimes be difficult to differentiate between maternal and adaptive maternal effects. consider the following: gypsy moths reared on foliage of black oak, rather than chestnut oak, had offspring that developed faster. this is a maternal, "not" an adaptive maternal effect. in order to be an adaptive maternal effect, the mother's environment would have to have led to a change in the eating habits or behavior of the offspring. the key difference between the two therefore, is that adaptive maternal effects are environment specific. the phenotypes that arise are in response to the mother sensing an environment that would reduce the fitness of her offspring. by accounting for this environment she is then able to alter the phenotypes to actually increase the offspring's fitness. "maternal" effects are not in response to an environmental cue, and further they have the potential to increase offspring fitness, but they may not.