M. Pearcy - Academia.edu (original) (raw)
Papers by M. Pearcy
... Bruxelles (Belgique) Michel Baguette Université Catholique de Louvain (Belgique) Alain Lenoir... more ... Bruxelles (Belgique) Michel Baguette Université Catholique de Louvain (Belgique) Alain Lenoir Université François-Rabelais, Tours (France) et Jacques M. Pasteels ... Une telle variation a été signalée à une occasion chez les mâles de l'abeille domestique (Harbo, 1990), mais ...
Many variations of the method are possible. The activity and affect descriptors used to describe ... more Many variations of the method are possible. The activity and affect descriptors used to describe episodes should fit the particular topic of investigation. Interactive questionnaires offer further opportunities to tailor the affect terms to the respective episode; for example, when the individual identifies an episode as an interaction with customers rather than with family members, different descriptors could be presented. Other variations could make the method more practical for adoption in conventional surveys. Our preliminary work suggests that much of the benefit of the DRM in producing accurate emotional recall could be retained if respondents are asked to retrieve specific recent episodes of a designated type (e.g., Bthe last occasion on which you went out to dinner[). When samples are large and interviewing time is scarce, the allocation of different situations to subgroups of respondents makes it possible to achieve comprehensive coverage of situations while minimizing respondent burden. In conjunction with timeuse data obtained from other sources, affect profiles of the main activities in which people engage could be integrated to produce a duration-weighted assessment of the experience of the population and of subgroups. The DRM or its variants could also contribute to the development of an accounting system for the well-being of society, a potentially important tool for social policy (32, 33).
Insectes Sociaux, 2013
ABSTRACT Desert ants of the genus Cataglyphis evolved a remarkable diversity in their reproductiv... more ABSTRACT Desert ants of the genus Cataglyphis evolved a remarkable diversity in their reproductive strategies. In Cataglyphis species where social organisation was described so far, colonies are headed by one or multiple queens, queens being singly or multiply mated, and workers and/or queens possess the ability to reproduce asexually via thelytokous parthenogenesis. Here, we investigate the social organisation of C. bombycina (group bombycinus) and C. theryi (group albicans) using highly polymorphic microsatellite markers. Our results show that both species are characterized by monogynous colonies and multiply mated queens, supporting the idea that polyandry is an ancestral trait of the genus. No evidence for parthenogenetic reproduction by queens was found. One distinctive feature of the species C. bombycina among the genus is the presence of a morphologically distinct soldier caste, with highly developed scythe blades jaws. In the only colony where a significant number of soldiers have been sampled, the distribution of patrilines is fundamentally different between the soldier and the worker caste. This result suggests a genetic contribution to worker caste determination in this species, and certainly awaits further investigation.
Heredity, 2006
Thelytokous parthenogenesis, that is, the production of diploid daughters from unfertilized eggs,... more Thelytokous parthenogenesis, that is, the production of diploid daughters from unfertilized eggs, may involve various cytological mechanisms, each having a different impact on the genetic structure of populations. Here, we determined the cytological mechanism of thelytokous parthenogenesis and its impact on inbreeding in the ant Cataglyphis cursor,a species where queens use both sexual and asexual reproduction to produce, respectively, workers and new queens. It has been suggested that thelytokous parthenogenesis in C. cursor might have been selected for to face high queen mortality and, originally, to allow workers to replace the queen when she passes away. We first determined the mode of thelytokous parthenogenesis by comparing the rate of transition to homozygosity at four highly polymorphic loci to expectations under the different modes of parthenogenesis. Our data show that thelytoky is achieved through automictic parthenogenesis with central fusion. We then estimated the proportion of colonies headed by worker-produced queens in a natural population. We designed a model linking the observed homozygosity in queens to the proportion of queens produced by workers, based on the assumption that (i) parthenogenesis is automictic with central fusion and (ii) queen lineage is asexually produced, resulting in an increase of the inbreeding over generations, whereas workers are sexually produced and therefore not inbred. Our results indicate that more than 60% of the colonies should be headed by a worker-produced queen, suggesting that queen's lifespan is low in this species.
Biology Letters, 2011
An enduring problem in evolutionary biology is the near ubiquity of sexual reproduction despite t... more An enduring problem in evolutionary biology is the near ubiquity of sexual reproduction despite the inherent cost of transmitting only half the parent's genes to progeny. Queens of some ant species circumvent this cost by using selectively both sexual reproduction and parthenogenesis: workers arise from fertilized eggs, while new queens are produced by parthenogenesis. We show that queens of the ant Cataglyphis cursor maximize the transmission rate of their genes by regulating the proportion of fertilized and parthenogenetic eggs laid over time. Parthenogenetic offspring are produced in early spring, when workers raise the brood into sexuals. After the mating period, queens lay mostly fertilized eggs that will be reared as the non-reproductive caste.
Biological Journal of the Linnean Society, 2008
HARDY, OJ, PEARCY, M. and ARON, S.(2008), Small-scale spatial genetic structure in an ant species... more HARDY, OJ, PEARCY, M. and ARON, S.(2008), Small-scale spatial genetic structure in an ant species with sex-biased dispersal. Biological Journal of the Linnean Society, 93: 465–473. doi: 10.1111/j. 1095-8312.2007. 00898. x
Behavioral Ecology, 2006
The local resource competition (LRC) hypothesis predicts that wherever philopatric offspring comp... more The local resource competition (LRC) hypothesis predicts that wherever philopatric offspring compete for resources with their mothers, offspring sex ratios should be biased in favor of the dispersing sex. In ants, LRC is typically found in polygynous (multiple queen) species where foundation of new nests occurs by budding, which results in a strong population structure and a male-biased population-wide sex ratio. However, under polygyny, the effect of LRC on sex allocation is often blurred by the effect of lowered relatedness asymmetries among colony members. Moreover, environmental factors, such as the availability of resources, have also been shown to deeply influence sex ratio in ants. We investigated sex allocation in the monogynous (single queen) ant Cataglyphis cursor, a species where colonies reproduce by budding and both male and female sexuals are produced through parthenogenesis, so that between-colony variations in relatedness asymmetries should be reduced. Our results show that sex allocation in C. cursor is highly male biased both at the colony and population levels. Genetic analyses indicate a significant isolation-by-distance in the study population, consistent with limited dispersal of females. As expected from asexual reproduction, only weak variations in relatedness asymmetry of workers toward sexual offspring occur across colonies, and they are not associated with colony sex ratio. Inconsistent with the predictions of the resource availability hypothesis, the male bias significantly increases with colony size, and investment in males, but not in females, is positively correlated with total investment in sexuals. Overall, our results are consistent with the predictions of the LRC hypothesis to account for sex ratio variation in this species.
... Bruxelles (Belgique) Michel Baguette Université Catholique de Louvain (Belgique) Alain Lenoir... more ... Bruxelles (Belgique) Michel Baguette Université Catholique de Louvain (Belgique) Alain Lenoir Université François-Rabelais, Tours (France) et Jacques M. Pasteels ... Une telle variation a été signalée à une occasion chez les mâles de l'abeille domestique (Harbo, 1990), mais ...
Many variations of the method are possible. The activity and affect descriptors used to describe ... more Many variations of the method are possible. The activity and affect descriptors used to describe episodes should fit the particular topic of investigation. Interactive questionnaires offer further opportunities to tailor the affect terms to the respective episode; for example, when the individual identifies an episode as an interaction with customers rather than with family members, different descriptors could be presented. Other variations could make the method more practical for adoption in conventional surveys. Our preliminary work suggests that much of the benefit of the DRM in producing accurate emotional recall could be retained if respondents are asked to retrieve specific recent episodes of a designated type (e.g., Bthe last occasion on which you went out to dinner[). When samples are large and interviewing time is scarce, the allocation of different situations to subgroups of respondents makes it possible to achieve comprehensive coverage of situations while minimizing respondent burden. In conjunction with timeuse data obtained from other sources, affect profiles of the main activities in which people engage could be integrated to produce a duration-weighted assessment of the experience of the population and of subgroups. The DRM or its variants could also contribute to the development of an accounting system for the well-being of society, a potentially important tool for social policy (32, 33).
Insectes Sociaux, 2013
ABSTRACT Desert ants of the genus Cataglyphis evolved a remarkable diversity in their reproductiv... more ABSTRACT Desert ants of the genus Cataglyphis evolved a remarkable diversity in their reproductive strategies. In Cataglyphis species where social organisation was described so far, colonies are headed by one or multiple queens, queens being singly or multiply mated, and workers and/or queens possess the ability to reproduce asexually via thelytokous parthenogenesis. Here, we investigate the social organisation of C. bombycina (group bombycinus) and C. theryi (group albicans) using highly polymorphic microsatellite markers. Our results show that both species are characterized by monogynous colonies and multiply mated queens, supporting the idea that polyandry is an ancestral trait of the genus. No evidence for parthenogenetic reproduction by queens was found. One distinctive feature of the species C. bombycina among the genus is the presence of a morphologically distinct soldier caste, with highly developed scythe blades jaws. In the only colony where a significant number of soldiers have been sampled, the distribution of patrilines is fundamentally different between the soldier and the worker caste. This result suggests a genetic contribution to worker caste determination in this species, and certainly awaits further investigation.
Heredity, 2006
Thelytokous parthenogenesis, that is, the production of diploid daughters from unfertilized eggs,... more Thelytokous parthenogenesis, that is, the production of diploid daughters from unfertilized eggs, may involve various cytological mechanisms, each having a different impact on the genetic structure of populations. Here, we determined the cytological mechanism of thelytokous parthenogenesis and its impact on inbreeding in the ant Cataglyphis cursor,a species where queens use both sexual and asexual reproduction to produce, respectively, workers and new queens. It has been suggested that thelytokous parthenogenesis in C. cursor might have been selected for to face high queen mortality and, originally, to allow workers to replace the queen when she passes away. We first determined the mode of thelytokous parthenogenesis by comparing the rate of transition to homozygosity at four highly polymorphic loci to expectations under the different modes of parthenogenesis. Our data show that thelytoky is achieved through automictic parthenogenesis with central fusion. We then estimated the proportion of colonies headed by worker-produced queens in a natural population. We designed a model linking the observed homozygosity in queens to the proportion of queens produced by workers, based on the assumption that (i) parthenogenesis is automictic with central fusion and (ii) queen lineage is asexually produced, resulting in an increase of the inbreeding over generations, whereas workers are sexually produced and therefore not inbred. Our results indicate that more than 60% of the colonies should be headed by a worker-produced queen, suggesting that queen's lifespan is low in this species.
Biology Letters, 2011
An enduring problem in evolutionary biology is the near ubiquity of sexual reproduction despite t... more An enduring problem in evolutionary biology is the near ubiquity of sexual reproduction despite the inherent cost of transmitting only half the parent's genes to progeny. Queens of some ant species circumvent this cost by using selectively both sexual reproduction and parthenogenesis: workers arise from fertilized eggs, while new queens are produced by parthenogenesis. We show that queens of the ant Cataglyphis cursor maximize the transmission rate of their genes by regulating the proportion of fertilized and parthenogenetic eggs laid over time. Parthenogenetic offspring are produced in early spring, when workers raise the brood into sexuals. After the mating period, queens lay mostly fertilized eggs that will be reared as the non-reproductive caste.
Biological Journal of the Linnean Society, 2008
HARDY, OJ, PEARCY, M. and ARON, S.(2008), Small-scale spatial genetic structure in an ant species... more HARDY, OJ, PEARCY, M. and ARON, S.(2008), Small-scale spatial genetic structure in an ant species with sex-biased dispersal. Biological Journal of the Linnean Society, 93: 465–473. doi: 10.1111/j. 1095-8312.2007. 00898. x
Behavioral Ecology, 2006
The local resource competition (LRC) hypothesis predicts that wherever philopatric offspring comp... more The local resource competition (LRC) hypothesis predicts that wherever philopatric offspring compete for resources with their mothers, offspring sex ratios should be biased in favor of the dispersing sex. In ants, LRC is typically found in polygynous (multiple queen) species where foundation of new nests occurs by budding, which results in a strong population structure and a male-biased population-wide sex ratio. However, under polygyny, the effect of LRC on sex allocation is often blurred by the effect of lowered relatedness asymmetries among colony members. Moreover, environmental factors, such as the availability of resources, have also been shown to deeply influence sex ratio in ants. We investigated sex allocation in the monogynous (single queen) ant Cataglyphis cursor, a species where colonies reproduce by budding and both male and female sexuals are produced through parthenogenesis, so that between-colony variations in relatedness asymmetries should be reduced. Our results show that sex allocation in C. cursor is highly male biased both at the colony and population levels. Genetic analyses indicate a significant isolation-by-distance in the study population, consistent with limited dispersal of females. As expected from asexual reproduction, only weak variations in relatedness asymmetry of workers toward sexual offspring occur across colonies, and they are not associated with colony sex ratio. Inconsistent with the predictions of the resource availability hypothesis, the male bias significantly increases with colony size, and investment in males, but not in females, is positively correlated with total investment in sexuals. Overall, our results are consistent with the predictions of the LRC hypothesis to account for sex ratio variation in this species.