Katherine E. Bruce

Agonistic relationships and sexual behaviour patterns in male guppies, Poecilia reticulata

Abstract Two experiments were conducted to assess the influence of agonistic relationships among male guppies on their sexual and aggressive behaviour under different social conditions. In experiment 1, each male of small mixed-sex groups of guppies was systematically removed and reintroduced to the group. Only during the alpha male reintroduction were there any changes in the sexual behaviour of the remaining males; the female-preferred sigmoid display of the beta males was depressed. During reintroductions, the alpha male was responsible for most aggression directed towards the reintroduced male. Females also responded aggressively towards the reintroduced males, particularly the alpha male. In experiment 2, an unfamiliar male was introduced to each established mixed-sex group. Again, rank-related behaviour was evident; most aggression directed towards the unfamiliar male was performed by the alpha male. The unfamiliar male also performed fewer sigmoid displays than did the alpha male. Thus, agonistic relationships among males may be responsible for suppression of sexual behaviour by subordinate and non-resident males and should be considered as a factor in sexual selection processes in guppies.

Matching- and Nonmatching-to-Sample Concept Learning in Rats using Olfactory Stimuli

Previous research has shown that rats can learn matching-to-sample relations with olfactory stimuli; however, the specific characteristics of this relational control are unclear. In Experiment 1, 6 rats were trained to either match or nonmatch to sample in a modified operant chamber using common household spices as olfactory stimuli. After matching or nonmatching training with 10 exemplars, the contingencies were reversed with five new stimuli such that subjects trained on matching were shifted to nonmatching and vice versa. Following these reversed contingencies, the effects of the original training persisted for many trials with new exemplars. In Experiment 2, 9 rats were trained with matching procedures in an arena that provided for 18 different spatial locations for comparison stimuli. Five subjects were trained with differential reinforcement outcomes and 4 with only one type of reinforcer. Differential outcomes and multiple exemplars facilitated learning, and there was strong evidence for generalization to new stimuli for most rats that acquired several conditional discriminations. Performances with novel samples were generally above chance, but rarely reached the high levels obtained during baseline with well-trained stimulus relations. However, taken together, the data from the two experiments extend previous work, show that rats can learn both match and nonmatch relations with different experimental protocols, and demonstrate generalization to novel sample stimuli.

The Development of Scales to Assess Knowledge and Attitudes about Genital Herpes

The Herpes Attitudes Scale (HAS) and the Herpes Knowledge Scale (HKS) were developed as research instruments to investigate knowledge and attitudes among college students about herpes. The HAS is a 40‐item Likert‐type scale with an internal consistency reliability coefficient of .91, based on a sample of 148 students. The HKS is a 54‐item true‐false test with a reliability coefficient of .88, with the same sample. Content validity of both scales was evaluated by a panel of judges knowledgeable about herpes and/or instrument construction. Since the scales are designed to detect unfavorable attitudes and general misconceptions about herpes, they can function in research applications and as both needs assessment and evaluative tools in herpes education programs.

The Effect of Male Familiarity on Proximity Time in Female Eastern Mosquitofish (Gambusia holbrooki)

Among live-bearing fish, females often prefer larger or more colorful males, or males engaging in ritualized courtship. However, in eastern mosquitofish, Gambusia holbrooki, the factors affecting females’ choice of males are unclear. We tested whether female Gambusia prefer to spend time near unfamiliar males over males with whom they have prior experience, expecting that females would prefer unfamiliar males. We examined both visual/olfactory and full exposure experience with males. As a control, we tested females with pairs of unfamiliar males. Control females showed no preferences between males. Females in the visual/olfactory experiment spent more time with males in general following 30-minute exposure, compared to 24-hour exposure. In the full exposure experiment, females spent more time with unfamiliar males only after 24 hours of previous exposure to the familiar male. We discuss the data in the context of mate choice, familiarity, female deprivation, and sexual satiation.

Behavioral pharmacology of the odor span task: Effects of flunitrazepam, ketamine, methamphetamine and methylphenidate

The Odor Span Task is an incrementing non-matching-to-sample procedure that permits the study of behavior under the control of multiple stimuli. Rats are exposed to a series of odor stimuli and selection of new stimuli is reinforced. Successful performance thus requires remembering which stimuli have previously been presented during a given session. This procedure has been frequently used in neurobiological studies as a rodent model of working memory; however, only a few studies have examined the effects of drugs on performance in this task. The present experiments explored the behavioral pharmacology of a modified version of the Odor Span Task by determining the effects of stimulant drugs methylphenidate and methamphetamine, NMDA antagonist ketamine, and positive GABAA modulator flunitrazepam. All four drugs produced dose-dependent impairment of performances on the Odor Span Task, but for methylphenidate and methamphetamine, these occurred only at doses that had similar effects on performance of a simple odor discrimination. Generally, these disruptions were based on omission of responding at the effective doses. The effects of ketamine and flunitrazepam were more selective in some rats. That is, some rats tested under flunitrazepam and ketamine showed decreases in accuracy on the Odor Span Task at doses that did not affect simple discrimination performance. These selective effects indicate disruption of within-session stimulus control. Overall, these findings support the potential of the Odor Span Task as a baseline for the behavioral pharmacological analysis of remembering.

Emergent identity but not symmetry following successive olfactory discrimination training in rats.

The search for symmetry in nonhuman subjects has been successful in recent studies in pigeons (e.g., Urcuioli, 2008). The key to these successes has been the use of successive discrimination procedures and combined training on identity, as well as arbitrary, baseline relations. The present study was an effort to extend the findings and theoretical analysis developed by Urcuioli and his colleagues to rats using olfactory rather than visual stimuli. Experiment 1 was a systematic replication of Urcuiolis (2008) demonstration of symmetry in pigeons. Rats were exposed to unreinforced symmetry probes following training with two arbitrary and four identity conditional discriminations. Response rates on symmetry probe trials were low and provided little evidence for emergent symmetry in any of the seven rats tested. In Experiment 2, a separate group of six rats was trained on four identity relations and was then exposed to probe trials with four novel odor stimuli. Response rates were high on identity probe trials, and low on nonmatching probe trials. The similar patterns of responding on baseline and probe trials that were shown by most rats provided a demonstration of generalized identity matching. These findings suggest that the development of stimulus control topographies in rats with olfactory stimuli may differ from those that emerge in pigeons with visual stimuli. Urcuiolis (2008) theory has been highly successful in predicting conditions necessary for stimulus class formation in pigeons, but may not be sufficient to fully understand determinants of emergent behaviors in other nonhuman species.

Successive odor matching- and non-matching-to-sample in rats: A reversal design

There is a growing body of research on matching- and non-matching-to-sample (MTS, NMTS) relations with rats using olfactory stimuli; however, the specific characteristics of this relational control are unclear. In the current study we examine MTS and NMTS in rats with an automated olfactometer using a successive (go, no-go) procedure. Ten rats were trained to either match- or non-match-to-sample with common scents (apple, cinnamon, etc.) as olfactory stimuli. After matching or non-matching training with four odorants, rats were tested for transfer twice with four new odorants on each test. Most rats trained on MTS showed immediate transfer to new stimuli, and most rats trained on NMTS showed full transfer by the second set of new odors. After meeting criterion on the second transfer test, the contingencies were reversed with four new odor stimuli such that subjects trained on matching were shifted to non-matching and vice versa. Following these reversed contingencies, the effects of the original training persisted for many trials with new odorants. These data extend previous studies on same-different concept formation in rats, showing strong generalization requiring few exemplars. The critical role of olfactory stimuli is discussed.