Effects of dispersant-treated oil upon behavioural and metabolic parameters of the anti-predator response in juvenile European sea bass (Dicentrarchus labrax).

Acute exposure to oil and oil dispersants can cause a wide range of physiological dysfunctions in marine fish species and evidences for consequences on behaviour are also increasing. In response to the presence of predators or to food availability, the modulation of locomotor activity and schools' behaviour enable fish to maximize their survival rates. However, the degree to which this regulatory process is affected by exposure to oil and/or dispersants is yet unknown. Here we investigated the effect of a 62-h experimental exposure to dispersant-treated oil on the behavioural (shoal cohesion, spontaneous activity) and metabolic (oxygen consumption) responses to simulated predation in juvenile European sea bass, Dicentrarchus labrax L. Our results suggest that exposure to petroleum hydrocarbons may affect negatively individual fitness through impaired ability to respond to predation. Shoal cohesion was not affected, but fish swimming activity was higher than control individuals under predation pressure and the amplitude of their metabolic response was significantly reduced. Fish recovered from alteration of their metabolic response 7 days post-exposure. Additionally, a strong habituation component was observed in C fish and the absence of such pattern in E fish suggest altered capacity to habituate over time to the surrounding environment and possible impairments of the related cognitive performances. Altogether, our data show that juvenile sea bass exposed to oil exhibit transient physiological dysfunctions and impairments of complex behaviours that may have major population-level consequences.

[The Alexithymia Questionnaire for Children (AQC): French translation and validation study in a convenience sample of 80 children]. / Le questionnaire d'alexithymie pour enfants (QAE): traduction française et étude de validation dans une population de 80 enfants « tout venant ¼.

INTRODUCTION: Alexithymia refers to a specific disturbance in psychic functioning characterized by a limited ability to identify and communicate one's feelings. Development of specific rating scales and notably the well-validated 20-item Toronto alexithymia Scale (TAS-20) have allowed the study of alexithymia in numerous samples of clinical or non-clinical subjects. Recently, Rieffe et al. [Pers and Individ Differ 40 (2006) 123-133] have developed an alexithymia questionnaire for children (AQC) basing on the TAS-20. The AQC comprised 20 items divided into three subscales: difficulty-identifying feelings (DIF), difficulty describing feelings (DDF) and externally-oriented thinking (EOT). Using a sample of 740 children and the Dutch version of the AQC the three-factor structure of alexithymia was found, using confirmatory factorial analysis, but the EOT factor showed low factor loadings and reliability. OBJECTIVE: The aim of the study was to present the French version of the AQC and to assess the psychometric properties of this version. METHODS: Eighty children recruited from a convenience sample were included in the study. There were 43 boys and 37 girls with a mean age of 11.81 (SD = 1.99, range: 9-16). The validity and the reliability of the AQC were studied using a confirmatory factorial analysis (CFA), the determination of the Cronbach alpha coefficient, and the calculation of the correlations between each item and the total score. RESULTS: Adequation parameters of the CFA showed that the 3-factor solution of the AQC was adequate (χ 2/df = 1.27, RMSEA = .039) although the EOT factor had low factor loadings. The Cronbach alpha coefficient was 0.64 and 15 items had significant correlations with the total score. CONCLUSION: The three-factor model of the AQC was reported for the French version of scale but the EOT factor had low validity. This result confirms the recent study using the Dutch version of the AQC. Moreover, several studies using foreign versions of the TAS-20 reported low reliability of the EOT factor. Thus, other studies are necessary to explore the reliability of the EOT factor of the French version of the AQC, and it's recommended to use only the total score of the AQC instead of the sub-scores.

Female-biased dispersal alone can reduce the occurrence of inbreeding in black grouse (Tetrao tetrix).

Although inbreeding depression and mechanisms for kin recognition have been described in natural bird populations, inbreeding avoidance through mate choice has rarely been reported suggesting that sex-biased dispersal is the main mechanism reducing the risks of inbreeding. However, a full understanding of the effect of dispersal on the occurrence of inbred matings requires estimating the inbreeding risks prior to dispersal. Combining pairwise relatedness measures and kinship assignments, we investigated in black grouse whether the observed occurrence of inbred matings was explained by active kin discrimination or by female-biased dispersal. In this large continuous population, copulations between close relatives were rare. As female mate choice was random for relatedness, females with more relatives in the local flock tended to mate with genetically more similar males. To quantify the initial risks of inbreeding, we measured the relatedness to the males of females captured in their parental flock and virtually translocated female hatchlings in their parental and to more distant flocks. These tests indicated that dispersal decreased the likelihood of mating with relatives and that philopatric females had higher inbreeding risks than the actual breeding females. As females do not discriminate against relatives, the few inbred matings were probably due to the variance in female dispersal propensity and dispersal distance. Our results support the view that kin discrimination mate choice is of little value if dispersal effectively reduces the risks of inbreeding.

Low levels of relatedness on black grouse leks despite male philopatry.

In lekking species, males cluster on specific areas for display (the leks) and females generally prefer to copulate with males on large aggregations. The maintenance of leks in which only a few males reproduce might be explained if subordinate males gain indirect fitness benefits. By joining a lek on which relatives are displaying, subordinates might attract more females to the lek thereby increasing the mating opportunities of their kin. In black grouse, a genetic structure among leks has previously been found suggesting that relatives could display together. Using 11 microsatellite loci, we extended this result by testing for the presence of kin structures in nine black grouse leks (101 males). The genetic differentiation among flocks was higher in males than in females, suggesting female-biased dispersal and male philopatry. Because of this genetic structure, males were more related within than among leks. However, the mean relatedness within each lek hardly differed from zero. The lekking males were not more related than random assortments of males from the winter flocks and there were no kin clusters within leks. Thus, black grouse males do not choose to display with and close to relatives. Male philopatry alone was not sufficient to induce elevated levels of relatedness on the leks either because of male partial dispersal or a rapid turnover of the successful males. The indirect fitness benefits associated with males' settlement decision are probably limited compared to the direct benefits of joining large aggregations such as increased current and future mating opportunities.

Restrictive mating by females on black grouse leks.

In bird species with pair bonds, extra-pair matings could allow females to choose genetically superior males. This is not needed in lekking species because female choice is not constrained by pairing opportunities. However, polyandry has been reported in most lekking species studied so far. Using 12 microsatellite loci, we determined the paternity of 135 broods of black grouse sampled between 2001 and 2005 (970 hatchlings and 811 adult birds genotyped). The paternity assignments were combined to lek observations to investigate the mating behaviour of black grouse females. About 10% of the matings seemed to take place with males displaying solitarily. Forty per cent of the copulations between males displaying on the studied leks and radio-tagged females were not recorded. This was due to difficulties in identifying the females and because our observations did not cover all the possible time for matings. However, females of the undetected copulations had chosen males that were already known to be successful on the leks. There was a strong consistency between the observations and true paternity, even when the copulation was disturbed by a neighbouring male. Multiple mating and multiple paternities were rare. We can now confidently ascertain that most females mate only once with one male for the whole clutch. This mating behaviour requires that a single insemination is sufficient to fertilize a clutch and that females can determine whether the sperm has been successfully transferred. Grouse Tetraoninae with many lekking species may be the only bird taxon that has evolved these traits.