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Linklater, W. L. (2000). Adaptive explanation in socio-ecology: lessons from the Equidae. Biol. Rev., 75(1), 1–20.
Abstract: Socio-ecological explanations for intra- and interspecific variation in the social and spatial organization of animals predominate in the scientific literature. The socio-ecological model, developed first for the Bovidae and Cervidae, is commonly applied more widely to other groups including the Equidae. Intraspecific comparisons are particularly valuable because they allow the role of environment and demography on social and spatial organization to be understood while controlling for phylogeny or morphology which confound interspecific comparisons. Feral horse (Equus caballus Linnaeus 1758) populations with different demography inhabit a range of environments throughout the world. I use 56 reports to obtain 23 measures or characteristics of the behaviour and the social and spatial organization of 19 feral horse populations in which the environment, demography, management, research effort and sample size are also described. Comparison shows that different populations had remarkably similar social and spatial organization and that group sizes and composition, and home range sizes varied as much within as between populations. I assess the few exceptions to uniformity and conclude that they are due to the attributes of the studies themselves, particularly to poor definition of terms and inadequate empiricism, rather than to the environment or demography per se. Interspecific comparisons show that equid species adhere to their different social and spatial organizations despite similarities in their environments and even when species are sympatric. Furthermore, equid male territoriality has been ill-defined in previous studies, observations presented as evidence of territoriality are also found in non-territorial equids, and populations of supposedly territorial species demonstrate female defence polygyny. Thus, territoriality may not be a useful categorization in the Equidae. Moreover, although equid socio-ecologists have relied on the socio-ecological model derived from the extremely diverse Bovidae and Cervidae for explanations of variation in equine society, the homomorphic, but large and polygynous, and monogeneric Equidae do not support previous socio-ecological explanations for relationships between body size, mating system and sexual dimorphism in ungulates. Consequently, in spite of the efforts of numerous authors during the past two decades, functional explanations of apparent differences in feral horse and equid social and spatial organization and behaviour based on assumptions of their current utility in the environmental or demographic context remain unconvincing. Nevertheless, differences in social cohesion between species that are insensitive to intra- and interspecific variation in habitat and predation pressure warrant explanation. Thus, I propose alternative avenues of inquiry including testing for species-specific differences in inter-individual aggression and investigating the role of phylogenetic constraints in equine society. The Equidae are evidence of the relative importance of phylogeny and biological structure, and unimportance of the present-day environment, in animal behaviour and social and spatial organization.
Keywords: *Adaptation, Physiological; Animals; Ecology; Equidae/*physiology; Female; Male; Phylogeny
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Neiworth, J. J., Hassett, J. M., & Sylvester, C. J. (2007). Face processing in humans and new world monkeys: the influence of experiential and ecological factors. Anim. Cogn., 10(2), 125–134.
Abstract: This study tests whether the face-processing system of humans and a nonhuman primate species share characteristics that would allow for early and quick processing of socially salient stimuli: a sensitivity toward conspecific faces, a sensitivity toward highly practiced face stimuli, and an ability to generalize changes in the face that do not suggest a new identity, such as a face differently oriented. The look rates by adult tamarins and humans toward conspecific and other primate faces were examined to determine if these characteristics are shared. A visual paired comparison (VPC) task presented subjects with either a human face, chimpanzee face, tamarin face, or an object as a sample, and then a pair containing the previous stimulus and a novel stimulus was presented. The stimuli were either presented all in an upright orientation, or all in an inverted orientation. The novel stimulus in the pair was either an orientation change of the same face/object or a new example of the same type of face/object, and the stimuli were shown either in an upright orientation or in an inverted orientation. Preference to novelty scores revealed that humans attended most to novel individual human faces, and this effect decreased significantly if the stimuli were inverted. Tamarins showed preferential looking toward novel orientations of previously seen tamarin faces in the upright orientation, but not in an inverted orientation. Similarly, their preference to look longer at novel tamarin and human faces within the pair was reduced significantly with inverted stimuli. The results confirmed prior findings in humans that novel human faces generate more attention in the upright than in the inverted orientation. The monkeys also attended more to faces of conspecifics, but showed an inversion effect to orientation change in tamarin faces and to identity changes in tamarin and human faces. The results indicate configural processing restricted to particular kinds of primate faces by a New World monkey species, with configural processing influenced by life experience (human faces and tamarin faces) and specialized to process orientation changes specific to conspecific faces.
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Ward, M. P., Ramsay, B. H., & Gallo, K. (2005). Rural cases of equine West Nile virus encephalomyelitis and the normalized difference vegetation index. Vector Borne Zoonotic Dis, 5(2), 181–188.
Abstract: Data from an outbreak (August to October, 2002) of West Nile virus (WNV) encephalomyelitis in a population of horses located in northern Indiana was scanned for clusters in time and space. One significant (p = 0.04) cluster of case premises was detected, occurring between September 4 and 10 in the south-west part of the study area (85.70 degrees N, 45.50 degrees W). It included 10 case premises (3.67 case premises expected) within a radius of 2264 m. Image data were acquired by the Advanced Very High Resolution Radiometer (AVHRR) sensor onboard a National Oceanic and Atmospheric Administration polar-orbiting satellite. The Normalized Difference Vegetation Index (NDVI) was calculated from visible and near-infrared data of daily observations, which were composited to produce a weekly-1km(2) resolution raster image product. During the epidemic, a significant (p < 0.01) decrease (0.025 per week) in estimated NDVI was observed at all case and control premise sites. The median estimated NDVI (0.659) for case premises within the cluster identified was significantly (p < 0.01) greater than the median estimated NDVI for other case (0.571) and control (0.596) premises during the same period. The difference in median estimated NDVI for case premises within this cluster, compared to cases not included in this cluster, was greatest (5.3% and 5.1%, respectively) at 1 and 5 weeks preceding occurrence of the cluster. The NDVI may be useful for identifying foci of WNV transmission.
Keywords: Animals; Biomass; Cluster Analysis; Disease Outbreaks/veterinary; Ecology; *Geographic Information Systems; Horse Diseases/*epidemiology; Horses; Indiana/epidemiology; Plants; Population Surveillance; Rural Health; Seasons; Topography, Medical/*methods; West Nile Fever/epidemiology/*veterinary
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Matsuzawa, T. (2003). The Ai project: historical and ecological contexts. Anim. Cogn., 6(4), 199–211.
Abstract: This paper aims to review a long-term research project exploring the chimpanzee mind within historical and ecological contexts. The Ai project began in 1978 and was directly inspired by preceding ape-language studies conducted in Western countries. However, in contrast with the latter, it has focused on the perceptual and cognitive capabilities of chimpanzees rather than communicative skills between humans and chimpanzees. In the original setting, a single chimpanzee faced a computer-controlled apparatus and performed various kinds of matching-to-sample discrimination tasks. Questions regarding the chimpanzee mind can be traced back to Wolfgang Koehler's work in the early part of the 20th century. Yet, Japan has its unique natural and cultural background: it is home to an indigenous primate species, the Japanese snow monkey. This fact has contributed to the emergence of two previous projects in the wild led by the late Kinji Imanishi and his students. First, the Koshima monkey project began in 1948 and became famous for its discovery of the cultural propagation of sweet-potato washing behavior. Second, pioneering work in Africa, starting in 1958, aimed to study great apes in their natural habitat. Thanks to the influence of these intellectual ancestors, the present author also undertook the field study of chimpanzees in the wild, focusing on tool manufacture and use. This work has demonstrated the importance of social and ecological perspectives even for the study of the mind. Combining experimental approaches with a field setting, the Ai project continues to explore cognition and behavior in chimpanzees, while its focus has shifted from the study of a single subject toward that of the community as a whole.
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Burke, D., Cieplucha, C., Cass, J., Russell, F., & Fry, G. (2002). Win-shift and win-stay learning in the short-beaked echidna (Tachyglossus aculeatus). Anim. Cogn., 5(2), 79–84.
Abstract: Numerous previous investigators have explained species differences in spatial memory performance in terms of differences in foraging ecology. In three experiments we attempted to extend these findings by examining the extent to which the spatial memory performance of echidnas (or “spiny anteaters”) can be understood in terms of the spatio-temporal distribution of their prey (ants and termites). This is a species and a foraging situation that have not been examined in this way before. Echidnas were better able to learn to avoid a previously rewarding location (to “win-shift”) than to learn to return to a previously rewarding location (to “win-stay”), at short retention intervals, but were unable to learn either of these strategies at retention intervals of 90 min. The short retention interval results support the ecological hypothesis, but the long retention interval results do not.
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Barker, S. C. (2003). The Australian paralysis tick may be the missing link in the transmission of Hendra virus from bats to horses to humans. Med Hypotheses, 60(4), 481–483.
Abstract: Hendra virus is a new virus of the family Paramyxoviridae. This virus was first detected in Queensland, Australia, in 1994; although, it seems that the virus has infected fruit-eating bats (flying-foxes) for a very long time. At least 2 humans and 15 horses have been killed by this virus since it first emerged as a virus that may infect mammals other than flying-foxes. Hendra virus is thought to have moved from flying-foxes to horses, and then from horses to people. There is a reasonably strong hypothesis for horse-to-human transmission: transmission of virus via nasal discharge, saliva and/or urine. In contrast, there is no strong hypothesis for flying-fox-to-human transmission. I present evidence that the Australian paralysis tick, Ixodes holocyclus, which has apparently only recently become a parasite of flying-foxes, may transmit Hendra virus and perhaps related viruses from flying-foxes to horses and other mammals.
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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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Mouritsen, K. N. (2001). Hitch-hiking parasite: a dark horse may be the real rider. Int J Parasitol, 31(13), 1417–1420.
Abstract: Many parasites engaged in complex life cycles manipulate their hosts in a way that facilitates transmission between hosts. Recently, a new category of parasites (hitch-hikers) has been identified that seem to exploit the manipulating effort of other parasites with similar life cycle by preferentially infecting hosts already manipulated. Thomas et al. (Evolution 51 (1997) 1316) showed that the digenean trematodes Microphallus papillorobustus (the manipulator) and Maritrema subdolum (the hitch-hiker) were positively associated in field samples of gammarid amphipods (the intermediate host), and that the behaviour of Maritrema subdolum rendered it more likely to infect manipulated amphipods than those uninfected by M. papillorobustus. Here I provide experimental evidence demonstrating that M. subdolum is unlikely to be a hitch-hiker in the mentioned system, whereas the lucky candidate rather is the closely related but little known species, Microphallidae sp. no. 15 (Parassitologia 22 (1980) 1). As opposed to the latter species, Maritrema subdolum does not express the appropriate cercarial behaviour for hitch-hiking.
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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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Sebastiani, F., Meiswinkel, R., Gomulski, L. M., Guglielmino, C. R., Mellor, P. S., Malacrida, A. R., et al. (2001). Molecular differentiation of the Old World Culicoides imicola species complex (Diptera, Ceratopogonidae), inferred using random amplified polymorphic DNA markers. Mol Ecol, 10(7), 1773–1786.
Abstract: Samples of seven of the 10 morphological species of midges of the Culicoides imicola complex were considered. The importance of this species complex is connected to its vectorial capacity for African horse sickness virus (AHSV) and bluetongue virus (BTV). Consequently, the risk of transmission may vary dramatically, depending upon the particular cryptic species present in a given area. The species complex is confined to the Old World and our samples were collected in Southern Africa, Madagascar and the Ivory Coast. Genomic DNA of 350 randomly sampled individual midges from 19 populations was amplified using four 20-mer primers by the random amplified polymorphic DNA (RAPD) technique. One hundred and ninety-six interpretable polymorphic bands were obtained. Species-specific RAPD profiles were defined and for five species diagnostic RAPD fragments were identified. A high degree of polymorphism was detected in the species complex, most of which was observed within populations (from 64 to 76%). Principal coordinate analysis (PCO) and cluster analysis provided an estimate of the degree of variation between and within populations and species. There was substantial concordance between the taxonomies derived from morphological and molecular data. The amount and the different distributions of genetic (RAPD) variation among the taxa can be associated to their life histories, i.e. the abundance and distribution of the larval breeding sites and their seasonality.
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