@article{3386,
  abstract     = {Evolutionary theories of ageing predict that life span increases with decreasing extrinsic mortality, and life span variation among queens in ant species seems to corroborate this prediction: queens, which are the only reproductive in a colony, live much longer than queens in multi-queen colonies. The latter often inhabit ephemeral nest sites and accordingly are assumed to experience a higher mortality risk. Yet, all prior studies compared queens from different single- and multi-queen species. Here, we demonstrate an effect of queen number on longevity and fecundity within a single, socially plastic species, where queens experience the similar level of extrinsic mortality. Queens from single- and two-queen colonies had significantly longer lifespan and higher fecundity than queens living in associations of eight queens. As queens also differ neither in morphology nor the mode of colony foundation, our study shows that the social environment itself strongly affects ageing rate.},
  author       = {Schrempf, Alexandra and Cremer, Sylvia and Heinze, Jürgen},
  journal      = {Journal of Evolutionary Biology},
  number       = {7},
  pages        = {1455 -- 1461},
  publisher    = {Wiley-Blackwell},
  title        = {{Social influence on age and reproduction reduced lifespan and fecundity in multi queen ant colonies}},
  doi          = {10.1111/j.1420-9101.2011.02278.x},
  volume       = {24},
  year         = {2011},
}

@article{3388,
  abstract     = {Background: Fragmentation of terrestrial ecosystems has had detrimental effects on metapopulations of habitat specialists. Maculinea butterflies have been particularly affected because of their specialized lifecycles, requiring both specific food-plants and host-ants. However, the interaction between dispersal, effective population size, and long-term genetic erosion of these endangered butterflies remains unknown. Using non-destructive sampling, we investigated the genetic diversity of the last extant population of M. arion in Denmark, which experienced critically low numbers in the 1980s. Results: Using nine microsatellite markers, we show that the population is genetically impoverished compared to nearby populations in Sweden, but less so than monitoring programs suggested. Ten additional short repeat microsatellites were used to reconstruct changes in genetic diversity and population structure over the last 77 years from museum specimens. We also tested amplification efficiency in such historical samples as a function of repeat length and sample age. Low population numbers in the 1980s did not affect genetic diversity, but considerable turnover of alleles has characterized this population throughout the time-span of our analysis. Conclusions: Our results suggest that M. arion is less sensitive to genetic erosion via population bottlenecks than previously thought, and that managing clusters of high quality habitat may be key for long-term conservation.},
  author       = {Ugelvig, Line V and Nielsen, Per and Boomsma, Jacobus and Nash, David},
  journal      = {BMC Evolutionary Biology},
  number       = {201},
  publisher    = {BioMed Central},
  title        = {{Reconstructing eight decades of genetic variation in an isolated Danish population of the large blue butterfly Maculinea arion}},
  doi          = {10.1186/1471-2148-11-201},
  volume       = {11},
  year         = {2011},
}

@article{3399,
  abstract     = {Context-dependent adjustment of mating tactics can drastically increase the mating success of behaviourally flexible animals. We used the ant Cardiocondyla obscurior as a model system to study adaptive adjustment of male mating tactics. This species shows a male diphenism of wingless fighter males and peaceful winged males. Whereas the wingless males stay and exclusively mate in the maternal colony, the mating behaviour of winged males is plastic. They copulate with female sexuals in their natal nests early in life but later disperse in search for sexuals outside. In this study, we observed the nest-leaving behaviour of winged males under different conditions and found that they adaptively adjust the timing of their dispersal to the availability of mating partners, as well as the presence, and even the type of competitors in their natal nests. In colonies with virgin female queens winged males stayed longest when they were the only male in the nest. They left earlier when mating partners were not available or when other males were present. In the presence of wingless, locally mating fighter males, winged males dispersed earlier than in the presence of docile, winged competitors. This suggests that C. obscurior males are capable of estimating their local breeding chances and adaptively adjust their dispersal behaviour in both an opportunistic and a risk-sensitive way, thus showing hitherto unknown behavioural plasticity in social insect males.},
  author       = {Cremer, Sylvia and Schrempf, Alexandra and Heinze, Jürgen},
  journal      = {PLoS One},
  number       = {3},
  publisher    = {Public Library of Science},
  title        = {{Competition and opportunity shape the reproductive tactics of males in the ant Cardiocondyla obscurior}},
  doi          = {10.1371/journal.pone.0017323},
  volume       = {6},
  year         = {2011},
}