Sabattini, M. S., Monath, T. P., Mitchell, C. J., Daffner, J. F., Bowen, G. S., Pauli, R., et al. (1985). Arbovirus investigations in Argentina, 1977-1980. I. Historical aspects and description of study sites. Am J Trop Med Hyg, 34(5), 937–944.
Abstract: This is the introductory paper to a series on the ecology of arboviruses in Argentina. Epizootics of equine encephalitis have occurred since at least 1908, principally in the Pampa and Espinal biogeographic zones, with significant economic losses; human cases of encephalitis have been rare or absent. Both western equine and eastern equine encephalitis viruses have been isolated from horses during these epizootics, but the mosquitoes responsible for transmission have not been identified. A number of isolations of Venezuelan equine encephalitis (VEE) virus were reported between 1936 and 1958 in Argentina, but the validity of these findings has been seriously questioned. Nevertheless, serological evidence exists for human infections with a member of the VEE virus complex. Serological surveys conducted in the 1960s indicate a high prevalence of infection of humans and domestic animals with St. Louis encephalitis (SLE), and 2 SLE virus strains have been isolated from rodents. Human disease, however, has rarely been associated with SLE infection. Only 7 isolations of other arboviruses have been described (3 of Maguari, 1 of Aura, 2 of Una, and 1 of an untyped Bunyamwera group virus). In 1977, we began longitudinal field studies in Santa Fe Province, the epicenter of previous equine epizootics, and in 1980 we extended these studies to Chaco and Corrientes provinces. The study sites are described in this paper.
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Barros, A. T. (2001). Seasonality and relative abundance of Tabanidae (Diptera) captured on horses in the Pantanal, Brazil. Mem Inst Oswaldo Cruz, 96(7), 917–923.
Abstract: Once a month, from June 1992 to May 1993, collections of tabanids on horse were conducted in the Nhecolandia, Pantanal State of Mato Grosso do Sul, Brazil. Tabanid catches using hand nets were conducted from sunrise to sunset at grassland and cerradao (dense savanna) habitats. A total of 3,442 tabanids from 21 species,12 genera, and 3 subfamilies were collected. Although species abundance varied seasonally depending on habitat, no habitat specificity was observed for the most abundant species. In the grassland, 1,625 (47.2%) tabanids belonging to 19 species were collected, while 1,817 (52.8%) tabanids from 17 species were caught in the cerradao. The number of tabanid species varied from 7 during winter (July/August) to 15 in the spring (October). Tabanus importunus (56%) was the most abundant species, followed by T. occidentalis (8.2%), and T. claripennis (8.1%). The tabanid peak, in October, coincided with the beginning of the rainy season. The population peak of most species, including those with higher vector potential, suggests that the rainy season can be considered as the period of potentially higher risk of mechanical transmission of pathogens by tabanids to horses in the region.
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Alexander, D. J. (1982). Ecological aspects of influenza A viruses in animals and their relationship to human influenza: a review. J R Soc Med, 75(10), 799–811.
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Bertram, D. S. (1971). Mosquitoes of British Honduras, with some comments on malaria, and on arbovirus antibodies in man and equines. Trans R Soc Trop Med Hyg, 65(6), 742–762.
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Dall, S. R. X., Houston, A. I., & McNamara, J. M. (2004). The behavioural ecology of personality: consistent individual differences from an adaptive perspective. Ecol. Letters, 7, 734–739.
Abstract: Individual humans, and members of diverse other species, show consistent differences in
aggressiveness, shyness, sociability and activity. Such intraspecific differences in
behaviour have been widely assumed to be non-adaptive variation surrounding
(possibly) adaptive population-average behaviour. Nevertheless, in keeping with recent
calls to apply Darwinian reasoning to ever-finer scales of biological variation, we sketch
the fundamentals of an adaptive theory of consistent individual differences in behaviour.
Our thesis is based on the notion that such .personality differences. can be selected for if
fitness payoffs are dependent on both the frequencies with which competing strategies
are played and an individual`s behavioural history. To this end, we review existing models
that illustrate this and propose a game theoretic approach to analyzing personality
differences that is both dynamic and state-dependent. Our motivation is to provide
insights into the evolution and maintenance of an apparently common animal trait:
personality, which has far reaching ecological and evolutionary implications.
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Marfin, A. A., Petersen, L. R., Eidson, M., Miller, J., Hadler, J., Farello, C., et al. (2001). Widespread West Nile virus activity, eastern United States, 2000. Emerg Infect Dis, 7(4), 730–735.
Abstract: In 1999, the U.S. West Nile (WN) virus epidemic was preceded by widespread reports of avian deaths. In 2000, ArboNET, a cooperative WN virus surveillance system, was implemented to monitor the sentinel epizootic that precedes human infection. This report summarizes 2000 surveillance data, documents widespread virus activity in 2000, and demonstrates the utility of monitoring virus activity in animals to identify human risk for infection.
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Scherer, W. F., Dickerman, R. W., & Ordonez, J. V. (1970). Discovery and geographic distribution of Venezuelan encephalitis virus in Guatemala, Honduras, and British Honduras during 1965-68, and its possible movement to Central America and Mexico. Am J Trop Med Hyg, 19(4), 703–711.
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Edman, J. D. (1971). Host-feeding patterns of Florida mosquitoes. I. Aedes, Anopheles, Coquillettidia, Mansonia and Psorophora. J Med Entomol, 8(6), 687–695.
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Wittemyer, G., & Getz, W. M. (2007). Hierarchical dominance structure and social organization in African elephants, Loxodonta africana. Anim. Behav., 73(4), 671–681.
Abstract: According to the socioecological framework, transitivity (or linearity) in dominance relationships is related to competition over critical resources. When a population is structured into groups, the intensity of between- versus within-group competition influences the form and function of its social organization. Few studies have compared the type and relative intensity of competition at these two levels. African elephants have well-structured social relations, providing an exemplary system for such a study. We report on dominance hierarchies among free-ranging elephants and evaluate the factors that drive their socioecological structure to lie in a region of the three-dimensional nepotism/despotism/tolerance space rarely observed among social species; namely, where non-nepotistic, transitive dominance hierarchies within groups emerge despite kin-based philopatry and infrequent agonistic interactions over widely distributed resources. We found significant transitivity in dominance hierarchies between groups. Dominance relations among the matriarchs of different social groups were primarily age based, rather than driven by physical or group size, and group matriarch rank influenced the dominance relationships among nonmatriarchal females in the population. Our results suggest that between-group dominance relationships induce tolerance among group members, which in combination with high group relatedness, reduces the benefits of nepotism. We postulate that cognitive abilities and high risk of injury in contests enhance winner and loser effects, facilitating the formation of transitive dominance relationships, despite widely distributed resources over which infrequent competition occurs. The interplay of cognitive abilities, winner and loser effects, resource distribution, and within- and between-group dominance relationships may produce behaviour in other strongly social mammals that differs from that predicted by a superficial application of current socioecological models.
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Krueger, K., Farmer, K., & Heinze, J. (2014). The effects of age, rank and neophobia on social learning in horses. Anim. Cogn., 17(3), 645–655.
Abstract: Social learning is said to meet the demands of complex environments in which individuals compete over resources and co-operate to share resources. Horses (Equus caballus) were thought to lack social learning skills because they feed on homogenously distributed resources with few reasons for conflict. However, the horse’s social environment is complex, which raises the possibility that its capacity for social transfer of feeding behaviour has been underestimated. We conducted a social learning experiment using 30 socially kept horses of different ages. Five horses, one from each group, were chosen as demonstrators, and the remaining 25 horses were designated observers. Observers from each group were allowed to watch their group demonstrator opening a feeding apparatus. We found that young, low ranking, and more exploratory horses learned by observing older members of their own group, and the older the horse, the more slowly it appeared to learn. Social learning may be an adaptive specialisation to the social environment. Older animals may avoid the potential costs of acquiring complex and potentially disadvantageous feeding behaviours from younger group members. We argue that horses show social learning in the context of their social ecology, and that research procedures must take such contexts into account. Misconceptions about the horse’s sociality may have hampered earlier studies.
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