No predator relies on the delta green ground beetle for a major portion of its food supply. The only habitat of delta green ground beetles is around pools formed by the collection of winter rains in low-lying areas. Because of their excellent camouflage, delta green ground beetles are almost impossible to see if they are not moving. Delta green ground beetles move about very little to get food; most of their moving from one place to another is related to their reproductive behavior.
Delta green ground beetles sometimes remain motionless for hours at a stretch, although they are more active in wet years than in dry years. In 1989 an observer spotted ten delta green ground beetles in nine hours; in 1985 the same observer at the same location had counted 38 in about two hours. This difference probably does not reflect a drop in the population of these rare beetles over this period, however, because 1985 was a wet year and 1989 was relatively dry.
Which one of the following, if true, most strongly supports the conclusion drawn above?