@article{MillesDammhahnGrimm2020,
  author    = {Milles, Alexander and Dammhahn, Melanie and Grimm, Volker},
  title     = {Intraspecific trait variation in personality-related movement behavior promotes coexistence},
  series = {Oikos},
  volume    = {129},
  journal   = {Oikos},
  number    = {10},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0030-1299},
  doi       = {10.1111/oik.07431},
  pages     = {1441 -- 1454},
  year      = {2020},
  abstract  = {Movement behavior is an essential element of fundamental ecological processes such as competition and predation. Although intraspecific trait variation (ITV) in movement behaviors is pervasive, its consequences for ecological community dynamics are still not fully understood. Using a newly developed individual-based model, we analyzed how given and constant ITVs in foraging movement affect differences in foraging efficiencies between species competing for common resources under various resource distributions. Further, we analyzed how the effect of ITV on emerging differences in competitive abilities ultimately affects species coexistence. The model is generic but mimics observed patterns of among-individual covariation between personality, movement and space use in ground-dwelling rodents. Interacting species differed in their mean behavioral types along a slow-fast continuum, integrating consistent individual variation in average behavioral expression and responsiveness (i.e. behavioral reaction norms). We found that ITV reduced interspecific differences in competitive abilities by 5-35\% and thereby promoted coexistence via an equalizing mechanism. The emergent relationships between behavioral types and foraging efficiency are characteristic for specific environmental contexts of resource distribution and population density. As these relationships are asymmetric, species that were either 'too fast' or 'too slow' benefited differently from ITV. Thus, ITV in movement behavior has consequences for species coexistence but to predict its effect in a given system requires intimate knowledge on how variation in movement traits relates to fitness components along an environmental gradient.},
  language  = {en}
}
@article{SteinhoffWarfenVoigtetal.2020,
  author    = {Steinhoff, Philip O. M. and Warfen, Bennet and Voigt, Sissy and Uhl, Gabriele and Dammhahn, Melanie},
  title     = {Individual differences in risk-taking affect foraging across different landscapes of fear},
  series = {Oikos},
  volume    = {129},
  journal   = {Oikos},
  number    = {12},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0030-1299},
  doi       = {10.1111/oik.07508},
  pages     = {1891 -- 1902},
  year      = {2020},
  abstract  = {One of the strongest determinants of behavioural variation is the tradeoff between resource gain and safety. Although classical theory predicts optimal foraging under risk, empirical studies report large unexplained variation in behaviour. Intrinsic individual differences in risk-taking behaviour might contribute to this variation. By repeatedly exposing individuals of a small mesopredator to different experimental landscapes of risks and resources, we tested 1) whether individuals adjust their foraging behaviour according to predictions of the general tradeoff between energy gain and predation avoidance and 2) whether individuals differ consistently and predictably from each other in how they solve this tradeoff. Wild-caught individuals (n = 42) of the jumping spiderMarpissa muscosa, were subjected to repeated release and open-field tests to quantify among-individual variation in boldness and activity. Subsequently, individuals were tested in four foraging tests that differed in risk level (white/dark background colour) and risk variation (constant risk/variable risk simulated by bird dummy overflights) and contained inaccessible but visually perceivable food patches. When exposed to a white background, individuals reduced some aspects of movement and foraging intensity, suggesting that the degree of camouflage serves as a proxy of perceived risk in these predators. Short pulses of acute predation risk, simulated by bird overflights, had only small effects on aspects of foraging behaviour. Notably, a significant part of variation in foraging was due to among-individual differences across risk landscapes that are linked to consistent individual variation in activity, forming a behavioural syndrome. Our results demonstrate the importance of among-individual differences in behaviour of animals that forage under different levels of perceived risk. Since these differences likely affect food-web dynamics and have fitness consequences, future studies should explore the mechanisms that maintain the observed variation in natural populations.},
  language  = {en}
}