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Pastoralism impacts the habitat quality of wild animals, while poaching is a direct threat to populations. The demographic effects of pastoralism are well known, whereas the effects of poaching are difficult to obtain. In addition, little attention has been paid to the role of tourism as a facilitator of poaching, especially when tourists feed animals and thus lower their fear of humans. In this paper, we investigate the demographic effects of pastoralism (a habitat quality indicator) and tourism (a poaching indicator) on wild Barbary macaques ( Macaca sylvanus) in Middle Atlas ( Morocco). Neither pastoralism nor tourism affected reproduction rates. High tourism pressure was related to a dramatic deficit in immature individuals. In groups near tourist sites, about half of the infants disappeared suggesting a high poaching pressure on these groups; as poachers select infants to sell as pets, infants used to seeing tourists probably constitute easy poaching targets. Group size and age structure were unrelated to the intensity of pastoralism. Groups were then half the size of those in undisturbed forests and in Middle Atlas 30 years ago. The effects of poaching are predicted to cause a severe collapse of the population. Our results demonstrate the need for Moroccan authorities to be aware of the conservation issues of Barbary macaques and to stop tourists feeding them. This research work illustrates that the potential links between tourism and poaching should be taken into account regarding species conservation, even in protected areas. [ABSTRACT FROM AUTHOR]

Three related Aphidius parasitoid species share the same host, the grain aphid Sitobion avenae. Among this parasitoid community, Aphidius rhopalosiphi is the most abundant species in the field. Both the interspecific host discrimination of A. rhopalosiphi towards hosts parasitized by the two other species (i.e. A. avenae and A. ervi) and the interspecific host discrimination of the two other species towards hosts parasitized by A. rhopalosiphi were studied here. Results showed that females of A. rhopalosiphi and A. avenae both discriminated between unparasitized hosts and hosts parasitized by the other species. This discrimination occurred only after ovipositor insertion, suggesting the perception of an internal marker of parasitism. Likewise, females of A. rhopalosiphi and A. ervi were able to discriminate between unparasitized hosts and hosts parasitized by the other species. However, in this combination of species, recognition of parasitized hosts occurred before ovipositor insertion, through an antennal perception, suggesting the presence an external cue indicating parasitism. Hence, interspecific host discrimination in the three Aphidius species is based on internal or external cues, which are used either alone or together. Our results showed that the cues used for interspecific host discrimination depend on the specific identity of the interaction. These differences seemed strongly linked to the way the different species respond to defensive behaviours of their aphid hosts. Results are discussed in the context of optimal foraging and possible consequences for community structure. [ABSTRACT FROM AUTHOR]

In order to establish whether commercial hybrid seed production between petalous and apetalous rapeseed lines could be developed through insect cross-pollination, observations were made to compare the foraging behaviour of honeybees on both flower types with regard to their attractiveness. Number of flowers/m² and nectar volumes, considered as important attractive factors, did not differ between the two lines but nectar sugar composition was slightly different. Honeybee density was significantly higher on the apetalous line when their foraging activity was rather high. Honeybees showed a considerable constancy to each flower type. Passages between both types were not very frequent. Nectar foraging behaviour, observed under cages, differed with the floral morphology. On the petalous flowers, honeybees visited the two inner nectaries by crawling over the anthers and the stigma, while on the apetalous ones they often inserted their tongues between the sepals, thus having less contact with the reproductive organs. From these results, the honeybee efficiency in cross-pollination between petalous and apetalous lines appears to be reduced. [ABSTRACT FROM AUTHOR]

Examines the effect of climate on the proportion of males in the autumn flight of aphid Rhopalosiphum padi in Great Britain. Reproduction of anholocycly; Composition of the autumn flights of cereal pest aphid; Factors affecting the geographical distribution of males.

The stylet penetration activities of Sitobion avenae F. were followed with an electronic method (DC-EPG) on resistant and susceptible wheat genotypes. Discriminant analysis was therefore applied to data evaluated on each electrical penetration graphs obtained (EPGs). The variables which mostly explained the resistance-susceptibility status of the wheat genotypes appeared to be related to the ingestion sap event (as represented by pattern E2), either to the time preceding first occurrence of a sap ingestion event or to the total time spent by the aphid ingesting sap from the sieve elements of the phloem. On the basis of their stylet penetration activities, individuals were separated into three blocks. The first one was made up the individuals tested on susceptible or slightly resistant wheat ('susceptible block'). The second one contained the individuals tested on two resistant genotypes ('resistant block l') and the third one regrouped the individuals tested on another resistant genotype ('resistant block 2'). These results are discussed in relation to the possible mechanisms of wheat resistance to S. avenae. [ABSTRACT FROM AUTHOR]

We assessed, using a modelling approach, the influence of several management practices within a farrow-to-finish farm on the age of PCV-2 infection. The impact of PCV-2 vaccination with different vaccination schemes on infection dynamics, was also tested. A stochastic individual-based model describing the population dynamics in a typical French farrow-to-finish pig farm was built and coupled with an epidemiological model of PCV-2 infection. The parameters of the infectious model were mainly obtained from previous transmission experiments. Results were subjected to a survival analysis of time-to-infection. For each comparison, the reference situation was no vaccination followed by random mixing of piglets after birth and after weaning. The risk of early infection was significantly reduced when mixing of piglets was reduced at different stages (avoiding cross-fostering and grouping piglets by litters in small pens after weaning, hazard ratio (HR)=0.52 [0.46; 0.59]). Sow-targeted vaccination delayed the infectious process until the waning of passive immunity and piglet-targeted vaccination considerably decreased the force of infection leading to a dramatic decrease of the total number of infections (HR=0.44 [0.37; 0.54]). The effect was even more pronounced when strict management measures were applied (HR=0.24 [0.19; 0.31]). Changing from a low (3%) prevalence of PCV-2-infected semen to a higher one (18%) significantly increased the risk of early infections (HR=1.36 [1.2; 1.53]), whereas reducing replacement rate or changing sow housing from individual crates to group housing had a limited impact on PCV-2 dynamics.

Six successive transmission trials were carried out from 4 to 39 days post inoculation (DPI) to determine the features of the infectious period for PCV2-infected pigs. The infectiousness of inoculated pigs, assessed from the frequency of occurrence of infected pigs in susceptible groups in each contact trial, increased from 4 to 18 DPI (0, 7 and 8 infected pigs at 4, 11 and 18 DPI, respectively) and then decreased slowly until 39 days post infection (4, 2 and 1 pigs infected at 25, 32 and 39 DPI, respectively). The estimated time-dependent infectiousness was fitted to three unimodal function shapes (gamma, Weibull and lognormal) for comparison. The absence of infected pigs at 4 DPI revealed a latency period between 4 and 10 DPI. A sensitivity analysis was performed to test whether the parametric shape of the transmission function influenced the estimations. The estimated time-dependent transmission rate was implemented in a deterministic SEIR model and validated by comparing the model prediction with external data. The lognormal-like function shape evidenced the best quality of fit, leading to a latency period of 8 days, an estimated basic reproduction ratio of 5.9 [1.8,10.1] and a mean disease generation time of 18.4 days [18.2, 18.5].

Branching processes are widely used in biology. This theoretical tool is used in cell dynamics, epidemics and population dynamics. In population dynamics, branching processes are mainly used to access extinction probabilities of populations, groups or families, with the Galton-Watson branching process. Many mammal species live in socially-structured groups, and the smallest units of these groups are lineages (or families) of kin-related individuals. In many primate species, these lineages are matrilines, as females remain in their natal groups most of the time, whereas males generally disperse. Lineage parameters, such as numbers of matrilines, size of each matriline and average degree of relatedness, could strongly influence the genetic composition of groups. Evidence indicates that division along matrilines could induce substantial differentiation among fission groups. Here, we develop a novel mathematical model based on the branching process theory describing demographic dynamics of groups. The main result of this model is an explicit analytical expression of the joint distribution of numbers of lineages and sizes of socially-structured groups. We investigated the influence of parameters such as natality and mortality on the outcome of the process, including extinction probability. Finally, we discuss this theoretical result with respect to biological significance.

Purpose: To determine the response of infants and children to the Moving Dynamic Random Dot Stereosize (MDRS) test and to collect cross-sectional age-related data., Methods: Sixty visually normal individuals were divided into four age groups: 0.5-<2, 2-<5, 5-<8, and 8-<20 years. Stereopsis was measured with the MDRS test on two occasions, plus the Frisby, Randot, or Stereo Smile tests, as was age appropriate., Results: All children aged >2 years and 80% of the children between ages 6 months and 2 years were able to perform the MDRS test on at least one occasion. Sixty percent of the 6-month to 2-year-old children were able to perform the Stereo Smile test on both occasions. Performance on the MDRS test improved with age up to 9 years. Improvement on the Frisby and Randot tests was seen in children aged up to 7 years. Mean and 95% confidence interval ranges for each test are given., Conclusion: This study gives evidence that aspects of the visual system are not fully mature until age 7-9 years. The MDRS test is a visually demanding but cognitively simple test that shows potential for detecting visual anomalies in young children.