Every half an hour we examined the females for attached spermatophores. High-risk sexual behavior among heterosexual undergraduates at a midwestern university. A participant was considered as having initiated sex if he or she responded negatively to both questions in prior waves of the survey and responded positively for the first time to either of two questions in the subsequent survey. Arnett notes that in the past several decades the experiences of most individuals between the ages of 18 and 25 who live in industrialized societies have undergone dramatic changes. During the last decade a few studies have tried to extract and characterize copepod pheromones, but so far without success. Here, we demonstrate that the swimming activity and velocity of males of a pelagic copepod, Oithona davisaeincreases in the presence of virgin when compared with mated females and that the cue is waterborne. Because we were unable to assess use of condoms or other contraceptives, it is not known whether or not the sexually active individuals practiced safer sex or how that may vary by degree of religiosity.
After this period 10 adult males were pipetted into each bottle with a minimum amount of water, resulting in a total number of 11 individuals per bottle.
We estimate that at realistic population densities the ability of males to distinguish between virgin and mated females saves them several hours per day of dangerous and energetically expensive fast female tracking. Receipt of a behavioral prevention intervention based on a cognitive model prevented Close mobile search navigation Article navigation. Sexually reproducing organisms have to find and identify potential partners to be able to produce offspring. Email alerts New issue alert. A general social psychological model for changing AIDS risk behavior.