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Traversa, D., Otranto, D., Iorio, R., & Giangaspero, A. (2005). Molecular characterization of Thelazia lacrymalis (Nematoda, Spirurida) affecting equids: a tool for vector identification. Mol Cell Probes, 19(4), 245–249.
Abstract: Equine thelaziosis caused by the eyeworm Thelazia lacrymalis is a parasitic disease transmitted by muscid flies. Although equine thelaziosis is known to have worldwide distribution, information on the epidemiology and presence of the intermediate hosts of T. lacrymalis is lacking. In the present work, a PCR-RFLP based assay on the first and/or second internal transcribed spacer (ITS1 and ITS2) of ribosomal DNA was developed for the detection of T. lacrymalis DNA in its putative vector(s). The sensitivity of the technique was also assessed. The restriction patterns obtained readily differentiated T. lacrymalis from four species of Musca (Diptera, Muscidae) (i.e. Musca autumnalis, Musca domestica, Musca larvipara and Musca osiris), which are potential vectors of equine eyeworms. The molecular assay presented herein is a useful tool to identify the intermediate host(s) of T. lacrymalis in natural conditions and to study its/their ecology and epidemiology.
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Hogan, J. (2005). Causation: the study of behavioural mechanisms. Animal Biology (formerly Netherlands Journal of Zoology), 55(4), 323–341.
Abstract: This paper describes current work on the causal analysis of behaviour systems. It is noted that while causal work investigating the neural, hormonal, and genetic bases of behaviour is flourishing, work being conducted at a strictly behavioural level of analysis has declined greatly over the past 40 years. Nonetheless, most recent research on animal cognition and applied ethology is still being carried out at a behavioural level of analysis and examples of both types of research are presented: memory mechanisms of food-storing birds and decisions of spider-eating jumping spiders, as well as feather pecking in fowl and animal welfare issues, are all briefly discussed. Finally, I discuss the similarities between neural network modelling and early ethological models of motivation, and then show how a modern version of Lorenz's model of motivation can account for current research findings on dustbathing in chickens and sleep in humans. I conclude that valuable information can still be obtained by research at a behavioural level of analysis.
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Bolhuis, J. (2005). Function and mechanism in neuroecology: looking for clues. Animal Biology (formerly Netherlands Journal of Zoology), 55(4), 457–490.
Abstract: The four questions that Niko Tinbergen identified for behavioural biology ? evolution, function, development and causation ? are all important and should be studied in their own right. Recently, there has been a debate as to whether these four questions should be investigated separately or whether they should be integrated. Integration of the four questions has been attempted in novel research disciplines such as cognitive ecology, evolutionary psychology and neuroecology. Euan Macphail and I have criticised these integrative approaches, suggesting that they are fundamentally flawed as they confound function and mechanism. Investigating the function or evolutionary history of a behaviour or cognitive system is important and entirely legitimate. However, such investigations cannot provide us with answers to questions about the mechanisms underlying behaviour or cognition. At most, functional or evolutionary considerations can provide clues that may be useful for a causal analysis of the underlying mechanisms. However, these clues can be misleading and are often wrong, as is illustrated with examples from song learning and food storing in birds. After summarising the main issues in the neuroecology debate, I discuss some misunderstandings that were apparent in the responses to our critique, as well as some recent relevant data. Recent results do not support the neuroecological approach. Finally, I suggest that the way forward is a cautious and critical use of functional and evolutionary clues in the study of the mechanisms of behaviour.
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Savage,, A. O., Kirsten Leong, Laura Graham, & Anne. (2005). Behavioral indices of estrus in a group of captive African elephants (Loxodonta africana). Zoo Biology, 24(4), 311–329.
Abstract: This study investigated behavioral signals of estrus by systematically monitoring the interactions of one male with four female African elephants housed in a naturalistic outdoor enclosure at Disney's Animal Kingdom over a period of 11 months. We measured changes in five spatial behaviors and 22 tactile-contact behaviors, as well as changes in serum progestagen and LH concentrations, across three ovarian cycles for each female. Two females did not cycle during the study. Three different phases of the ovarian cycle were identified: mid luteal, anovulatory follicular, ovulatory follicular. The male followed more and carried out more genital inspections, flehmen, and trunk-to-mouth behaviors toward cycling females during their ovulatory phase. Genital inspections by the male peaked above baseline levels on the day of an LH surge, and up to 9 days before, in both cycling females and, thus, might be a useful behavioral index of estrus. The male also carried out more genital inspections, flehmen, and trunk touches to the back leg toward ovulatory cycling than noncycling females. Overall, our results indicated that: 1) a single subadult African elephant male could discriminate two females in the ovulatory phase of their cycle (i.e., during the 3 weeks preceding ovulation) from the mid luteal phase; 2) the male also discriminated two cycling females in the ovulatory and anovulatory follicular phases from two noncycling females; 3) two females in the ovulatory phase of the cycle displayed a greater variety of tactile-contact behavior toward the male compared to the other cycle phases. Zoo Biol 0:1-19, 2005. – 2005 Wiley-Liss, Inc.
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Callow, N., & Waters, A. (2005). The effect of kinesthetic imagery on the sport confidence of flat-race horse jockeys. Psychology of Sport and Exercise, 6(4), 443–459.
Abstract: Objectives The primary objective was to examine the efficacy of a kinesthetic imagery intervention on the sport confidence of three professional flat-race horse jockeys, with the secondary objective of examining the relationship between performance and sport confidence.Design A multiple-baseline across participants research design was employed.Methods The State Sport Confidence Inventory [SSCI; Vealey, R.S. (1986). Conceptualization of sport confidence and competitive orientation: Preliminary investigation and instrument development. Journal of Sport Psychology, 8, 221-246.] was administered twice weekly, prior to a total of 23, 25, and 27 races for participants 1, 2, and 3, respectively. In addition, performance data were collected on each SSCI data collection day. The kinesthetic imagery intervention consisted of six kinesthetic imagery sessions, twice weekly during a 3-week period. The intervention was introduced after race 7, 9, and 11 for participants 1, 2, and 3, respectively. Approximately, 1 week after the end of the data collection, participants completed a postexperimental questionnaire.Results ITSACORR [Crosbie, J. (1993). Interrupted time-series analysis with brief single-subject data. Journal of Consulting and Clinical Psychology, 6, 966-974.] was employed to analyze the sport confidence data. The results of ITSACORR along with visual inspection, demonstrated a significant increase in sport confidence for participants 1 and 3, and a non-significant increase for participant 2. Kendall's tau b correlations failed to find a significant relationship between performance and confidence.Conclusions The results are discussed in terms of the value of kinesthetic imagery as a tool for athletes to practice and develop. Furthermore, this study demonstrates the ability of ITSACORR to provide a statistical analysis for serially dependent single-subject data.
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Young, L. E., Rogers, K., & Wood, J. L. N. (2005). Left ventricular size and systolic function in Thoroughbred racehorses and their relationships to race performance. J Appl Physiol, 99(4), 1278–1285.
Abstract: Cardiac morphology in human athletes is known to differ, depending on the sports-specific endurance component of their events, whereas anecdotes abound about superlative athletes with large hearts. As the heart determines stroke volume and maximum O(2) uptake in mammals, we undertook a study to test the hypothesis that the morphology of the equine heart would differ between trained horses, depending on race type, and that left ventricular size would be greatest in elite performers. Echocardiography was performed in 482 race-fit Thoroughbreds engaged in either flat (1,000-2,500 m) or jump racing (3,200-6,400 m). Body weight and sex-adjusted measures of left ventricular size were largest in horses engaged in jump racing over fixed fences, compared with horses running shorter distances on the flat (range 8-16%). The observed differences in cardiac morphologies suggest that subtle differences in training and competition result in cardiac adaptations that are appropriate to the endurance component of the horses' event. Derived left ventricular mass was strongly associated with published rating (quality) in horses racing over longer distances in jump races (P < or = 0.001), but less so for horses in flat races. Rather, left ventricular ejection fraction and left ventricular mass combined were positively associated with race rating in older flat racehorses running over sprint (<1,408 m) and longer distances (>1,408 m), explaining 25-35% of overall variation in performance, as well as being closely associated with performance in longer races over jumps (23%). These data provide the first direct evidence that cardiac size influences athletic performance in a group of mammalian running athletes.
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König, H. E., Wissdorf, H., Probst, A., Macher, R., Voß, S., & Polsterer, E. (2005). Considerations about the function of the mimic muscles and the vomeronasal organ of horses during the Flehmen reaction. Pferdeheilkunde, 21(4), 297–300.
Abstract: Additional to the olfactory epithelium, the equine vomeronasal organ serves to the perception of odorous substances and specially for pheromones. In a middle-size horse this organ has an extension in length from an imaginary transverse plane about 10 cm caudally the nostrils to a transverse plane through the middle of the second premolar tooth. During the Flehmen reaction the levator labii superior, nasolabial, caninus and lateralis nasi muscles contract. The upper lip and the tip of the nose are lifted. The opening of the nostrils is narrowed, caused by the convergence of the plate and horn of the alar cartilage. In this manner in case of Flehmen reaction air is directly conducted towards the opening of the vomeronasal organ into the nasal cavity during inspiration. During the “Flehmen” horses assume a characteristic posture.
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Vallortigara, G., & Rogers, L. J. (2005). Survival with an asymmetrical brain: advantages and disadvantages of cerebral lateralization. Behav Brain Sci, 28(4), 575–89; discussion 589–633.
Abstract: Recent evidence in natural and semi-natural settings has revealed a variety of left-right perceptual asymmetries among vertebrates. These include preferential use of the left or right visual hemifield during activities such as searching for food, agonistic responses, or escape from predators in animals as different as fish, amphibians, reptiles, birds, and mammals. There are obvious disadvantages in showing such directional asymmetries because relevant stimuli may be located to the animal's left or right at random; there is no a priori association between the meaning of a stimulus (e.g., its being a predator or a food item) and its being located to the animal's left or right. Moreover, other organisms (e.g., predators) could exploit the predictability of behavior that arises from population-level lateral biases. It might be argued that lateralization of function enhances cognitive capacity and efficiency of the brain, thus counteracting the ecological disadvantages of lateral biases in behavior. However, such an increase in brain efficiency could be obtained by each individual being lateralized without any need to align the direction of the asymmetry in the majority of the individuals of the population. Here we argue that the alignment of the direction of behavioral asymmetries at the population level arises as an “evolutionarily stable strategy” under “social” pressures occurring when individually asymmetrical organisms must coordinate their behavior with the behavior of other asymmetrical organisms of the same or different species.
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Harewood, E. J., & McGowan, C. M. (2005). Behavioral and physiological responses to stabling in naive horses. J. Equine Vet. Sci., 25(4), 164–170.
Abstract: The purpose of this study was to investigate the response of horses to confinement and isolation in a stable (indoor individual housing) for the first time using behavioral indices, heart rate, and salivary cortisol concentration. Six naive 2-year-old Australian Stock Horse fillies were examined at 4-hour intervals over 24 hours in an outdoor group paddock followed by 24 hours in indoor individual housing. Behavioral observations and scores and heart rates were recorded and saliva samples were taken at each interval. During stabling, all horses became agitated and demonstrated increased vocalization and movement. Behavioral scores were significantly higher in the indoor individual housing (P < .001). No significant difference in heart rates between the two environments was detected. Mean salivary cortisol did not increase significantly (2 ng/mL ± 1.4 ng/mL in outdoor group paddock vs 2.5 mL ± 1.2 ng/mL in indoor individual housing). No diurnal rhythm in salivary cortisol was evident in either the outdoor group paddock or indoor individual housing. The results of this study highlight that a combination of behavioral and physiological measures allow better understanding of stress, where one measurement may be misleading. First time stabling of horses elicited marked behavioral responses indicative of stress that were not reflected in increased heart rates or salivary cortisol concentrations. The lack of a diurnal cortisol rhythm and the comparatively high basal cortisol concentrations found in the outdoor group paddock environment may imply that the fillies were already stressed; therefore, stabling did not cause further aberrations detectable by salivary cortisol analysis.
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de Waal, F. B. M., Dindo, M., Freeman, C. A., & Hall, M. J. (2005). The monkey in the mirror: hardly a stranger. Proc. Natl. Acad. Sci. U.S.A., 102(32), 11140–11147.
Abstract: It is widely assumed that monkeys see a stranger in the mirror, whereas apes and humans recognize themselves. In this study, we question the former assumption by using a detailed comparison of how monkeys respond to mirrors versus live individuals. Eight adult female and six adult male brown capuchin monkeys (Cebus apella) were exposed twice to three conditions: (i) a familiar same-sex partner, (ii) an unfamiliar same-sex partner, and (iii) a mirror. Females showed more eye contact and friendly behavior and fewer signs of anxiety in front of a mirror than they did when exposed to an unfamiliar partner. Males showed greater ambiguity, but they too reacted differently to mirrors and strangers. Discrimination between conditions was immediate, and blind coders were able to tell the difference between monkeys under the three conditions. Capuchins thus seem to recognize their reflection in the mirror as special, and they may not confuse it with an actual conspecific. Possibly, they reach a level of self-other distinction intermediate between seeing their mirror image as other and recognizing it as self.
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