Georges Gonzalez

Sarcoptes scabiei: Specific immune response to sarcoptic mange in the Iberian ibex Capra pyrenaica depends on previous exposure and sex.

Host acquired immunity is a critical factor that conditions the survival of parasites. Nevertheless, there is a shortage of data concerning inter-individual immunological inequalities in wild mammals. Sarcoptic mange is a widespread parasitosis that severely affects mammals such as the Iberian ibex (Capra pyrenaica). Despite some work on the subject, the immune response to sarcoptic mange infestation is still a complex and poorly understood phenomenon. To improve knowledge of the host-Sarcoptes immunological interaction, 18 Iberian ibexes were experimentally infested. IgG levels were assessed using ELISA to test for potential factors determining the specific immune response to infestation. Previous exposure and sex appeared to affect the IgG response to infestation and our results suggest a sex-biased immunomodulation. We discuss the immunological pattern of host-Sarcoptes interactions and also suggest further lines of work that may improve the understanding of immunological interactions of host-Sarcoptes systems.

Diurnal and seasonal variations of roaring activity of farmed red deer stags

Various environmental and social parameters are known to affect the roaring activity of the red deer (Cervus elaphus) stags, but their influence is difficult to estimate in the field. We consequently studied the diurnal changes in roaring activity of three adult stags kept in separate paddocks with hinds over the course of a breeding season during seven 24 h field sessions. Roaring activity started at the end of September, peaked for all three stags in mid-October before ceasing abruptly about a week later. Both the hourly number of roar bouts and the hourly number of roars emitted differed between stags and sessions: the youngest (5-year-old) stag roared more at the beginning of the rut, while roaring of the two other stags (11- and 12-year-old) progressively increased over the season. However, at the peak, the roaring activity of the three stags was similar. During the two first weeks of October, the roaring activity of the two more vocal stags significantly decreased just before sunrise and at least 2.5 h after sunset, while it significantly increased during daytime. The implications of these results for estimating the population size of free ranging red deer based on roaring activity of stags are briefly discussed.

Population size, distribution and status of the remote and Critically Endangered Bawean deer Axis kuhlii

Conservation of rare ungulates requires reliable population size estimates and distribution maps for prioritizing investments and assessing the effectiveness of conservation measures. We used both camera trapping and a random encounter model approach, and faecal pellet group counts, to update the range and population size of the Bawean deer Axis kuhlii in the Bawean Island Nature Reserve and Wildlife Sanctuary, Indonesia. We studied 2-month periods to fulfil the assumption of population closure. Both methods provided similar population density estimates (higher in the dry season) of c. 227–416 individuals. The estimated range of the species is significantly narrower than previously reported. The main threats (habitat loss as a result of illegal logging, and disturbance by dogs and hunters) are ongoing. Based on these results we suggest that the species should retain its Critically Endangered status on the IUCN Red List.

Benefit of camera trapping for surveying the critically endangered Bawean deer Axis kuhlii (Temminck, 1836)

Despite being one of the rarest deer in the world, the critically endangered Bawean deer Axis kuhlii has received little conservation attention. Fauna monitoring is usually limited by lack of resource; therefore, the choice of a relevant methodology is fundamental to maximize the cost–benefit ratio. We compared the performance and cost of three direct and indirect methods to survey Bawean deer in protected areas of Bawean Island. Camera trapping provided a high number of records of Bawean deer (118 for 5500 camera days) and ascertained identifications of several other species. The number of photographs increased with the dry season. Transect sampling was time-consuming in the field for a poor result (two records for 19.200 h). Faecal pellet group count was more successful (80 pellet groups for 9.600 h of fieldwork). Camera traps are expensive to buy, but they lighten the field work and provide much data for further analyses.

Is dominance the only factor determining access to food in an agonistic context? An experiment with captive male mouflon

In fulfilling their daily activities, animals must expend the least amount of energy possible while feeding in order to optimise their energy balance. Food is removed by congeners as a result of exploitation competition. When a resource becomes limited, an increase in the probability of interference competition (direct competition for the resource) is triggered. While a high social rank may increase foraging time and resource access, this status also has detrimental facets. To explore the benefits of dominance/aggression in a context where true monopolisation of resources could be advantageous, we tested three hypotheses related to the patchiness of resources, agonistic activity (i.e. dominance and aggression) and individual attributes (i.e. morphology and behaviour) in a group of captive mouflon males (Ovis ammon musimon). Feeding performance was analysed using linear mixed models based on predictors about patchiness of the resource, and behavioural and morphological indices. No clear relationship was found between dominance and feeding performance. However, the general pattern showed (i) a decrease in overall feeding performance with the dispersion of the resource; (ii) that the discrepancy in feeding performance among individuals was maximal when confronted with intermediate conditions; and (iii) that alternative tactics allowed subordinate individuals to achieve a similar feeding performance to dominants. The results of this study suggest that, over and above agonistic behaviour and dominance, the motivation of individuals and its variation over time, though difficult to evaluate, could be key to understanding the coexistence of alternative behavioural tactics.

La domestication des animaux par les hommes préhistoriques: By D. Helmer. Masson, France, 1992, 180 pp. plus 59 figures, ISBN 2-225-82473-8, 145FF

“noise”. On the other hand, it is often interesting to have the subject choose between two or many intervals, one of which contains the stimulus. In many circumstances, two intervals are more effective than one-interval designs. For instance in some word recognition experiments, when subjects have to determine whether a given word has been presented or not during the study phase, familiarity due to lexical frequency may be confounded with familiarity due to recent exposure. Presenting a distractor of variable lexical frequency allows to control for familiarity using a forced choice procedure. In the same vein, one can use pairs of stimuli that differ by one feature only and ask the subject whether they are different. It is a convenient way to control for the feature the subjects uses. Sophisticated designs involving three stimuli (e.g. two standard stimuli are first presented and then the subject must determine which of those matches a third one> are also described. Models are provided for all those designs as well as guidelines regarding which one to use. Finally, part III generalizes the paradigm to larger contexts and part IV covers specifically statistical questions. Chapter 8 addressed a generalized threshold estimation problem: finding the stimulus difference that corresponds to a given sensitivity level. Chapters 9 and 10 generalize to classification experiments either by considering many stimuli classes or by considering multidimensional descriptions of the stimulus. There are many examples throughout the book, not only from psychophysical experiments but also from memory experiments or from perception or medical research. A serious effort has obviously been made to cover a large variety of designs. The book convincingly demonstrates how SDT can be put to good use in various experimental contexts. It will certainly be very helpful to students and researchers in behavioural science.