The EICA‐hypothesis predicts that invading plants adapt to their novel environment by evolving increased performance and reduced resistance in response to the release from natural enemies, and assumes a resource allocation tradeoff among both trait groups as mechanistic basis of this evolutionary change. Using the plant Silene latifolia as a study system, we tested these predictions by investigating whether 1) invasive populations evolved lower resistance and higher performance, 2) this evolutionary change is indeed adaptive, and 3) there is a negative genetic correlation between performance and resistance (i.e. a tradeoff) in native and introduced individuals. Moreover, we sampled eight native and eight invasive populations and determined their population co‐ancestry based on neutral SSR‐markers. We performed controlled crossings to produce five sib‐groups per population and exposed them to increased and reduced levels of enemy attack in a full‐factorial experiment to estimate performance and resistance. With these data, we performed trait‐by‐trait comparisons between ranges with ‘animal models’ that account for population co‐ancestry to quantify the amount of variance in traits explained by non‐adaptive versus adaptive evolution. Moreover, we tested for genetic correlations among performance and resistance traits within sib‐groups. We found significant reductions in resistance and increases in performance in invasive versus native populations, which could largely be attributed to adaptive evolution. While we detected a non‐significant trend towards negative genetic performance × resistance correlations in native populations, invasive populations exhibited both significant and non‐significant positive correlations. In summary, these results do not support a shift of performance and resistance trait values along a tradeoff line in response to enemy release, as predicted by EICA. They rather suggest that the independent evolution of both traits is not constrained by a tradeoff, and that various selective agents (including resource availability) interact in shaping both traits and in weakening negative genetic correlations in the invaded habitat.
In a major disaster with more than 200 seriously injured patients the EVK model is a practicable and regional well tried solution that could increase the capacity of hospital admissions and advanced trauma life support, regardless of the type of casualty, season or weather conditions. It is possible to reduce the interval to advanced trauma life support, temporary fracture stabilization (damage control) and definitive surgical care by means of rapid and targeted utilization of resources and manpower. Physicians involved in the initial treatment play a key role and have to be highly trained (ATLS). The EVK model is variable and can easily be established and adapted to regional conditions at basic regional hospitals as well as at level I trauma centers.
Inbreeding and enemy infestation are common in plants and can synergistically reduce their performance. This inbreeding ×environment (I × E) interaction may be of particular importance for the success of plant invasions if introduced populations experience a release from attack by natural enemies relative to their native conspecifics. Here, we investigate whether inbreeding affects plant infestation damage, whether inbreeding depression in growth and reproduction is mitigated by enemy release, and whether this effect is more pronounced in invasive than native plant populations. We used the invader Silene latifolia and its natural enemies as a study system. We performed two generations of experimental out‐ and inbreeding within eight native (European) and eight invasive (North American) populations under controlled conditions using field‐collected seeds. Subsequently, we exposed the offspring to an enemy exclusion and inclusion treatment in a common garden in the species’ native range to assess the interactive effects of population origin (range), breeding treatment, and enemy treatment on infestation damage, growth, and reproduction. Inbreeding increased flower and leaf infestation damage in plants from both ranges, but had opposing effects on fruit damage in native versus invasive plants. Inbreeding significantly reduced plant fitness; whereby, inbreeding depression in fruit number was higher in enemy inclusions than exclusions. This effect was equally pronounced in populations from both distribution ranges. Moreover, the magnitude of inbreeding depression in fruit number was lower in invasive than native populations. These results support that inbreeding has the potential to reduce plant defenses in S. latifolia, which magnifies inbreeding depression in the presence of enemies. However, future studies are necessary to further explore whether enemy release in the invaded habitat has actually decreased inbreeding depression and thus facilitated the persistence of inbred founder populations and invasion success.
37Inbreeding and enemy infestation are common in plants and can synergistically reduce their 38 performance. This inbreeding × environment (I×E) interaction may be of particular 39 importance for the success of plant invasions if introduced populations experience a release 40 from attack by natural enemies relative to their native conspecifics. Using native and invasive 41 plant populations, we investigate whether inbreeding affects infestation damage, whether 42 inbreeding depression in performance is mitigated by enemy release and whether genetic 43 differentiation among native and invasive plants modifies these I×E interactions. We used the 44 plant invader Silene latifolia and its natural enemies as a study system. We performed two 45 generations of experimental out-and inbreeding within eight native (European) and eight 46 invasive (North American) S. latifolia populations under controlled conditions using field-47 collected seeds. Subsequently, we exposed the offspring to an enemy exclusion and 48 inclusion treatment in a common garden in the species' native range to assess the interactive 49 effects of population origin (range), breeding treatment and enemy treatment on infestation 50 damage as well as plant performance. Inbreeding increased flower and leaf infestation 51 damage in plants from both ranges, but had opposing effects on fruit damage in native 52 versus invasive plants. Both inbreeding and enemy infestation had negative effects on plant 53 performance, whereby inbreeding depression in fruit number was higher in enemy inclusions 54 than exclusions in plants from both ranges. Moreover, the magnitude of inbreeding 55 depression in fruit number was lower in invasive than native populations. Our results support 56 that inbreeding increases enemy susceptibility of S. latifolia, which magnifies inbreeding 57 depression in the presence of enemies. Enemy release in the invaded habitat may thus 58 increase the persistence of inbred founder populations and thereby contribute to successful 59 invasion. Moreover, our findings emphasize that genetic differentiation among native and 60 invasive plants can shape the magnitude and even the direction of inbreeding effects. 61 4 Keywords 62 biological invasion, genetic differentiation, genetic paradox, herbivory, purging, white 63 campion 64Understanding the forces that promote or prevent species range expansions remains a 66 challenging goal in ecology (Barrett, 2015). During invasion of a new range, populations can 67
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