Fulhorst, C. F., Hardy, J. L., Eldridge, B. F., Chiles, R. E., & Reeves, W. C. (1996). Ecology of Jamestown Canyon virus (Bunyaviridae: California serogroup) in coastal California. Am J Trop Med Hyg, 55(2), 185–189.
Abstract: This paper reports the first isolation of Jamestown Canyon (JC) virus from coastal California and the results of tests for antibody to JC virus in mammals living in coastal California. The virus isolation was made from a pool of 50 Aedes dorsalis females collected as adults from Morro Bay, San Luis Obispo County, California. The virus isolate was identified by two-way plaque reduction-serum dilution neutralization tests done in Vero cell cultures. Sera from the mammals were tested for antibody to JC virus by a plaque-reduction serum dilution neutralization method. A high prevalence of JC virus-specific antibody was found in horses and cattle sampled from Morro Bay. This finding is additional evidence for the presence of a virus antigenically identical or closely related to JC virus in Morro Bay and indicates that the vectors of the virus in Morro Bay feed on large mammals. A high prevalence of virus-specific antibody was also found in horses sampled from Marin and San Diego counties. This finding suggests that viruses antigenically identical or closely related to JC virus are geographically widespread in coastal California.
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Atwill, E. R., Mohammed, H. O., & Lopez, J. W. (1996). Evaluation of travel and use as a risk factor for seropositivity to Ehrlichia risticii in horses of New York state. Am J Vet Res, 57(3), 272–277.
Abstract: OBJECTIVES--To determine whether mean annual frequency and destination of equine travel was associated with exposure to Ehrlichia risticii and whether these associations were modified by horses' place of residence. DESIGN--Cross-sectional study. SAMPLE POPULATION--511 equine operations containing 2,587 horses were visited in New York state from a target population of 39,000 operations. PROCEDURE--Each horse was tested for serum antibodies against E risticii, using indirect fluorescent antibody. Information on the horse's travel history, farm's management practices, and surrounding ecology was obtained by personal interview and resource maps. Statistical analyses were performed on 2 cohorts of animals: all horses enrolled in the study and horses born on the property or that resided at least 4 years on the farm. Three county-based risk regions (RR) were identified by use of cluster analysis. RESULTS--Mean seroprevalence for each of the 3 RR was 2.4 (low risk), 8.5 (moderate risk), and 18.5% (high risk) for cohort 1 and 2.5, 8.0, and 18.4% for cohort 2. Among cohorts 1 and 2, pleasure riding and breeding trips were associated with exposure to E risticii, but horse residence (low, moderate, or high RR) was an effect modifier for these associations. Among cohort 1 and stratifying the analysis according to the RR for the travel destination, trail riding at low RR and trail riding at high RR were associated with exposure. Among cohort 2 and stratifying the analysis according to the RR for the travel destination, breeding trips were associated with exposure, and strong effect modification was present for horse residence (low, moderate, or high RR). CONCLUSIONS--Only certain types of travel to specific RR were associated with higher risk of exposure to E risticii. In many instances, travel was not associated, or was associated, with a reduced risk of exposure.
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Doré, F. Y., Fiset, S., Goulet, S., Dumans, M. - C., & Gagnon, S. (1996). Search behavior in cats and dogs Interspecific differences in working memory and spatial cognition. Anim Learn. & Behav., 24(2), 142–149.
Abstract: Cats and dogs search behavior was compared in different problems where an object was visibly
moved behind a screen that was then visibly moved to a new position. In Experiments 1 (cats) and 2 (dogs),
one group was tested with identical screens and the other group was tested with dissimilar screens.
Results showed that in both species, search behavior was based on processing of spatial information
rather than on recognition of the visual features of the target screen. Cats and dogs were unable to find
the object by inferring its invisible movement. They reached a high level of success only if there was
direct perceptual evidence that the object could not be at its initial position. When the position change
was indicated by an indirect cue, cats searched more at the object`s initial than final position, whereas
dogs searched equally at both positions. Interspecific similarities and differences are interpreted in
terms of the requirements for resetting working memory.
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Kaseda, Y., & K. Nozawa, K. (1996). Father-daughter matings and its avoidance in Misaki feral horses. Anim Sci Tech, 67(11), 996–1002.
Abstract: Father-daughter matings and its avoidance mechanism were analysed on the basis of data which gained from behavioural observations and paternity tests in Misaki feral horses from 1979 to 1994. Twelve stallions and their 51 daughters had 176 breeding seasons, but they lived in the different home range in 82 breeding seasons. About half of 1- to 3-year-old mares emigrated from natal area to the other and grew up there. Therefore, emigrations of young mares may result reduction of contacts and avoidance of inbreeding with their fathers. The stallions and their daughters lived in the same area in 94 breeding seasons, but there were no cases that daughters which left their natal harem groups before sexual maturity formed again stable consort relations with their natal harem stallions. It is possible that separation of young mares from their natal groups before sexual maturity may result avoidance of formation of consort relation with their fathers. Two father-daughter matings were observed in 124 paternity tests. These two daughters were born in the other harem groups than their father's and left their natal groups before maturity. After maturity, one of them formed a stable consort relation with her father and the other remained together with her father for 2 months in the breeding season. Both of them had not experience to have lived with their fathers before maturity. The persent result supports the hypothesis in wild and semi-wild horses that inbreedings between fathers and daughters may be avioded by the experience to have lived together before sexual maturity.
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Wilson, D. S., & Dugatkin, L. A. (1996). A reply to Lombardi & Hurlbert. Anim. Behav., 52(2), 423–425.
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Dugatkin, L. A. (1996). Tit for Tat, by-product mutualism and predator inspection: a reply to Connor. Anim. Behav., 51(2), 455–457.
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Galef, B. G. (1996). The adaptive value of social learning: a reply to Laland. Anim. Behav., 52(3), 641–644.
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Brunner, D., Kacelnik, A., & Gibbon, J. (1996). Memory for inter-reinforcement interval variability and patch departure decisions in the starling,Sturnus vulgaris. Anim. Behav., 51(5), 1025–1045.
Abstract: An experiment with starlings was conducted to investigate the effect of variability in inter-reinforcement intervals on foraging decisions. The experimental design simulated an environment in which food was distributed in patches. Patches contained zero to four food items which could be collected by pecking at a key. All patches ended with sudden depletion. The time elapsed since the last reinforcement was the only way to detect the depletion of the patch. Once a patch was depleted, a new patch could be reached by completion of a travel requirement of 20 flights between two perches. Key pecks within a patch and the time of the last response in a patch (giving-in time) were recorded. The level of variability in the inter-reinforcement intervals was varied between different conditions. An increase in inter-reinforcement interval variability resulted in a flattening of response rate functions and giving-in time distributions, and in more asymmetry of the response functions, but not of the giving-in time distributions. Two theoretical models of decision making are presented, which differ in the assumptions about memory constraints. In one case, all inter-reinforcement intervals are remembered but in the other, only the intervals with extreme values are remembered. Both models accommodate response rates as a function of trial time, but only the second is compatible with the observed departure decision. Our results are compatible with net rate maximization.
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Monard, A. - M., & Duncan, P. (1996). Consequences of natal dispersal in female horses. Anim. Behav., 52(3), 565–579.
Abstract: Social, genetic and reproductive consequences of natal dispersal were investigated in female horses,Equus caballus, living in a herd with a natural social structure. Dispersal did not as a rule reduce the level of competition the young mares faced: they did not selectively join groups with fewer resident females than the groups they left, and they did not attain higher ranks; there was also no tendency for females to disperse to groups with the fewest resident females, and they suffered more aggression from the mares in their new groups than in their natal groups. These results therefore do not support the hypothesis that a function of natal dispersal is to reduce intra-sexual competition. The young mares nevertheless dispersed non-randomly, generally joining harems with one stallion and at least two subadult females; and they preferred to move to groups with familiar females but no familiar males. As a result, most were closely related to some females of their new groups, but distantly related or unrelated to the male(s). Since after dispersal the young mares bred only with a male of their new groups, inbreeding coefficients of most (85%) of their offspring were lower than from matings between half siblings. These results are consistent with the hypothesis that a function of natal dispersal is to avoid close inbreeding. Dispersal did not appear to involve reproductive costs: the young mares suffered no delay in age at first reproduction, and the survival rates of their first foals tended to be higher if the females had emigrated, although not significantly so.
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Heyes CM. (1996). Self-recognition in primates: irreverence, irrelevance and irony. Anim. Behav., 51, 470.
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