Gerard Dizinno

Ultrasonic vocalizations by male mice (Mus musculus) to female sex pheromone: Experiential determinants.

Adult male mice (Mus musculus), separated from females at weaning, did not emit 70-kHz courtship ultrasounds to female urine. Other adult males that in addition were given 3-min exposures per day to stimulus females and males for 8 consecutive days later emitted many ultrasounds to female urine. However, even those males that initially responded to female urine typically ceased responding during the course of repeated presentations of female urine. This loss of responsiveness to urine did not generalize to female stimuli. Thus, both the acquisition and maintenance of the male ultrasonic response to female urine are affected by experiential factors.

Female odors evoke ultrasounds from male mice

Four experiments investigated the stimulus properties of female mice that influence ultrasound production by adult males. Female urine alone was less effective in evoking ultrasounds than was the female in male-female pairs. Visual cues were not necessary, since there was no difference in the incidence or latency of ultrasounds from male-female pairs when tested in light and dark conditions. A presently unspecified chemical cue produced by females, whose effectiveness is mediated by olfaction, was sufficient to evoke ultrasounds from male mice. The role of this chemical cue in a multimodal sequential communicative chain is discussed.

Androgen influence on male mouse ultrasounds during courtship.

Abstract Ultrasonic vocalizations are emitted by adult male mice (Mus musculus) shortly after an adult female or her odor are encountered, possibly as an early part of courtship behavior. Consistent with this hypothesis, it was found that castration of adult male mice increased the latency to first ultrasonic vocalization in response to an adult female. In addition, castrated males, subsequently injected once with 200 μg of testosterone propionate, reduced their latency, whereas oil-injected castrates did not.

Social status and ultrasonic vocalizations of male mice

Dominant male mice (Mus musculus) emit much more 70-kHz ultrasound in response to females than do subordinates. Neither dominant nor subordinate males emit much ultrasound in response to male stimuli. Inhibition of initial courtship by social subordination may be a central factor contributing to the greater reproductive fitness of dominant males.

A NOTE ON MEASURING APPREHENSION ABOUT WRITING

Having revised Daly and Millers 1975 unidimensional Writing Apprehension Test, Riffe and Stacks in 1992 proposed eight multidimensional factors derived from responses to 56 items in their Mass Communication Writing Apprehension Measure, administered to communication students to identify the various dimensions of apprehension about writing shared with business writers and specific to their major. The current authors administered the questionnaire at the beginning of an academic year to 419 freshmen from all undergraduate schools and majors at a private liberal arts university. It was hypothesized that the factors found among the homogeneous population of communication majors would not be replicated among the more heterogeneous student population. The hypothesis was partially upheld. Seven factors were identified. Two duplicated most items found by Riffe and Stacks (1992), four added items, and one was new. The results of this study suggest that, although the general population of students differs from students in mass communication, as Riffe and Stacks remarked, the groups also share similar content in their writing apprehension, that writing apprehension is multidimensional, that caution must be exercised when administering any instrument for the diagnostic and counseling purposes suggested by Riffe and Stacks, and that writing apprehension should also be investigated from the perspective of locus of control.

Ventral marking in black and agouti gerbils (Meriones unguiculatus)

Male and female Mongolian gerbils (Meriones unguiculatus) of both agouti and black coat color variations were tested for ventral marking in an open field. Males marked more than females and black gerbils marked more than the agouti animals. Black females marked at levels equal to those of agouti males, and thus they may be useful in future investigations of neural and hormonal factors affecting ventral marking in females. Such research was difficult in the past because of the extremely low levels of marking normally exhibited by agouti females.