Poisonous plants are an integral part of many pastures destined for horses around the world. However, fundamental knowledge of the role of horses’ senses in discriminating these plants is still ...lacking. It is, therefore, of interest to study whether, besides sight, the olfaction used by animals before ingesting may prevent them eating a poisonous plant. The aim of the study was to determine whether stabled horses are capable of distinguishing poisonous plants solely by odour among the unfamiliar plants presented. Twenty adult warmblood mares and geldings were involved in the study. The novel plants presented for exploration by the horses were three poisonous species: Taxus baccata, Buxus sempervirens and Thuja occidentalis, as well as three non-poisonous species: Petroselinum crispum, Anethum graveolens and Eruca sativa. Each plant was presented in a small box for one minute on three days, two plants daily. The plants were unavailable to see or touch by the horses and only smell was perceptible. The horses were habituated and positively conditioned to approach the box. The intensity of exploration was measured by the number of exploration events, total exploration time and occurrence of additional behaviours, such as chewing. The method used made it possible to exclude other senses than smell and a previous experience with the plants tested from the analysis. The time of exploration in subsequent trials was found to be shortened (9.0, 5.5, 3.0 s for poisonous plants and 14.5, 7.0, 5.5 s for non-poisonous plants). The differences in the time spent exploring boxes with different plants show that horses discriminate new odours individually and undertake increased olfactory behaviours when encountering a novel odour. The horses spent significantly more time exploring non-poisonous than poisonous plants (7.0 and 5.0 s, respectively). They were also chewing and licking the crib notably more often when non-poisonous plants were presented compared to poisonous plants (0.24 and 0.13 versus 0.15 and 0.08, respectively). The shortened and weaker exploration in the case of poisonous plants may indicate that these plants caused a reluctance in the horses. Hence, our findings suggest that the horses’ sense of smell has some potential for differentiating poisonous from non-poisonous plants independently of the sense of taste, touch and sight.
•Horses show varying responses towards odours of unfamiliar plant species.•Horses attend less to poisonous plants compared with non-poisonous plants.•Horses may discriminate unknown poisonous and non-poisonous plants by olfaction.
Anaesthetic efficacy of eugenol was investigated on Pterophyllum scalare. A total of 130 fish with average weights of 1.0 ± 0.5, 5.0 ± 1.0 and 10.0 ± 1.0 g were subjected to 1.25, 2.5, 4.0, 5.5 and ...7.0 mg/L eugenol, and behavioural responses were observed. Induction and recovery times were significantly affected by the interactive effect of eugenol concentration and fish weight (p < .05). Generally, 49.9–128 s after exposure to 1.25–7 mg/L eugenol, fish reached stage 3. Fish entered stage 4 over 55–135 s post exposure to such concentrations. Recovery time was 393.5–597.7 s in all sizes. Any increase in eugenol concentration led to a significant decrease in the induction time with a subsequent increment of the recovery time. Concentrations of eugenol and fish size along with their interactive effects have significantly contributed to the regression models, with concentration recording the highest beta values for stages 1, 2, 3 and 4 (−0.903, −0.898, −0.976 and −0.864 respectively) and the product of size and anaesthetic concentration for full recovery in smaller fish (0.647) and eugenol concentration in larger ones (0.967). Recovery time was fitted to induction time to stage 4 via quadratic and linear regression models in smaller and larger fish respectively. Results revealed the minimal eugenol concentration to induce anaesthesia in various size classes of angelfish in less than 3 min was 1.25 mg/L. Our results showed eugenol as an effective and safe anaesthetic; however, it is not advisable for live fish transportation.
Anaesthetic efficacy of eugenol was investigated on Flowerhorn (Amphilophus labiatus × Amphilophus trimaculatus). A total of 104 fish with average weights of 12 ± 2.5, 28 ± 5 and 53 ±5.1 g were ...subjected to 25–200 mg L−1 eugenol and behavioural responses as well as induction and recovery times were recorded. Induction and recovery times were significantly affected by eugenol concentration as well as fish weight (P < 0.05). Generally, 49.9–127.3 s after exposure to 50–200 mg L−1 eugenol, fish reached stage 3 anaesthesia (suitable for general handling). Fish entered stage 4 anaesthesia (suitable for surgery and blood sampling) over 57.3–140.4 s post exposure to such concentrations. Recovery time was 91.7–312 s in all weight classes for all eugenol concentrations. Mortality (23%) was only observed in 12‐g fish when were subjected to 200 mg L−1 eugenol. This study showed the behavioural response of Flowerhorn to anaesthesia and eugenol efficacy as an anaesthetic in this important ornamental species. The general quadratic equation revealed that concentrations of eugenol and fish size along with their interactive effects have significantly contributed to the model, with concentration recording the highest beta value in all models (β = −0.809, −0.818 and −0.909, P = 0.000). According to the results, minimum eugenol concentration to induce anaesthesia in less than 3 min was 50 mg L−1.
Efficient estimation of the population size from dependent dual-record system (DRS) remains a statistical challenge in the capture-recapture type experiment. Owing to the non-identifiability of the ...suitable time-behavioural response variation model (denoted as Mtb) under DRS, few methods are developed in the Bayesian paradigm based on informative priors. Our contribution in this article is to develop a new integrated likelihood function from model Mtb motivated by a novel approach developed by Severini (2007). A suitable weight function on the nuisance parameter is derived with the knowledge of the direction of behavioural dependency. A pseudo-likelihood function is constructed so that the resulting estimator possess some desirable properties including negligible prior (or weight) sensitiveness. Extensive simulations show the superior performance of our proposed method to that of the existing Bayesian methods. Moreover, the proposed estimator is easy to implement from the computational perspective. Applications to two real data sets are presented.
L’estimation efficace de la taille d’une population à partir d’un système à enregistrement double (SED) dépendant demeure un défi statistique de taille pour les expériences de type capture-recapture. Peu de méthodes ont été développées dans un cadre bayésien avec des lois a priori informatives, surtout à cause de la non-identifiabilité du modèle pour la variation temporelle du comportement (dénoté Mtb) avec un SED. Les auteurs développent une nouvelle fonction de vraisemblance intégrée à partir du modèle Mtb motivée par une approche novatrice proposée par Severini (2007). Ils dérivent une fonction de pondération appropriée pour les paramètres de nuisance avec la connaissance de la direction de la variation temporelle du comportement. Ils construisent une fonction de pseudo vraisemblance conférant à l’estimateur obtenu des propriétés désirables, notamment une sensibilité négligeable à la loi a priori et à la pondération. De plus, l’estimateur proposé est facile à implémenter d’un point de vue numérique. Les auteurs présentent une vaste étude de simulation démontrant les performances supérieures offertes par la méthode proposée par rapport aux méthodes bayésiennes existantes. Ils en présentent également l’application à deux jeux de données réelles.
•Only four of the five servicescape dimensions contribute to explaining ‘Pleasure’ and ‘Arousal’.•‘Spaciousness’ was the most important dimension in predicting guests’ ‘Favourable behaviours’.•None ...of the dimensions affected propensity to spend.•Both ‘Pleasure’ and ‘Arousal’ had a positive influence on ‘Favourable behaviours’.•Only ‘Pleasure’ was found to be significant in the explanation of ‘Propensity to spend’.
Previous research shows some links between customers’ perceptions of their service experience in hotels, overall satisfaction and enhanced sales revenue. However, the ways in which the servicescape influences the customer and their perceptions of the hotel experience remains relatively unexplored.
This study explores the links between customers’ perceptions of the hotel servicescape and their emotional and behavioural responses. Previous research has used scales developed for other industrial contexts and this study aims to develop an instrument directly relevant to the hotel context. To achieve this goal, a recently developed hotel specific servicescape scale was used but both the emotional and behavioural response scales were developed based on existing research but expanded to include items specifically for hotel customers.
Using a large-scale survey of hotel customers in London, analysis showed two dimensions of emotional responses and two dimensions of behavioural responses to be both valid and reliable for the hotel context. The study then successfully determined the relationship between five hotel servicescape dimensions and customers’ emotional states and their behavioural responses. The findings showed the ways in which the hotel servicescape significantly affects both emotional and behavioural responses, having clear implications for both hotel design and management. The results also raised a number of interesting and potentially rewarding areas for further research.
Shipping is the dominant marine anthropogenic noise source in the world's oceans, yet we know little about vessel encounter rates, exposure levels and behavioural reactions for cetaceans in the wild, ...many of which rely on sound for foraging, communication and social interactions. Here, we used animal-borne acoustic tags to measure vessel noise exposure and foraging efforts in seven harbour porpoises in highly trafficked coastal waters. Tagged porpoises encountered vessel noise 17–89% of the time and occasional high-noise levels coincided with vigorous fluking, bottom diving, interrupted foraging and even cessation of echolocation, leading to significantly fewer prey capture attempts at received levels greater than 96 dB re 1 µPa (16 kHz third-octave). If such exposures occur frequently, porpoises, which have high metabolic requirements, may be unable to compensate energetically with negative long-term fitness consequences. That shipping noise disrupts foraging in the high-frequency-hearing porpoise raises concerns that other toothed whale species may also be affected.
Invasive predators not only cause native prey populations to decline but can also induce evolutionary changes in their behaviour in a short time scale. However, few studies have reported these rapid ...responses. This could be because strong predation pressure by invasive species often causes the extinction of native prey before an evolutionary effect can be detected. Recently, eradication projects successfully removed invasive predators and resulted in the recovery of native prey. We predicted that rapid responses can be detected by evaluating the behavioural traits of native prey populations having different histories of predator invasion. We examined the behavioural responses of a native frog, the Amami tip‐nosed frog (Odorrana amamiensis), to an invasive mongoose (Herpestes auropunctatus) on Amami Island, Japan. The native frog population was reduced by the mongoose; however, the eradication project leads to the recovery of the native frog population, thereby providing an opportunity to evaluate the evolutionary impact of the invasive species. We hypothesized that spatial differences in flight initiation distance (FID) can be explained by spatial patterns of past mongoose predation pressure. We used a spatial model based on generalized least squares regression methods to test the effects of potential factors on FID. We then performed model comparison and model averaging. We found that the native frog became more sensitive to the approach of a potential predator as the historical impact of the mongoose increased, suggesting that past strong predation pressure by the mongoose drove a rapid behavioural response in the native frog. Our study suggests that rapid behavioural responses of other native species can be detected not only after successful eradication projects, but also on currently invaded sites with different invasion histories.
Invasive predators not only cause native prey populations to decline but can also induce evolutionary changes in their behaviour in a short time scale. However, few studies have reported these rapid responses. We found that the spatially heterogeneous anti‐predator response of a native frog can be explained by the spatial gradation of past predation pressure from the invasive mongoose. This means that past strong predation pressure by the invasive mongoose drove a rapid behavioural response in the native frog and the behavioural change remains even after mongooses have been mostly removed by eradication project. This result suggests that we can detect rapid behavioural responses of the native species in many other cases following successful eradication projects.
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