Abstracts (first author)


Artificial selection for host-plant use of a seed-predator: fitness consequences, inbreeding depression, and genetic variation


Author(s): Muola A, Laukkanen L, Leimu R, Mutikainen P


The use of alternative, suboptimal food-plant species affect herbivore’s fitness and life-history, and thus has both ecological and evolutionary consequences. Our study species, the seed predator Lygaeus equestris uses Vincetoxicum hirundinaria as its primary food plant. However, extensive spatio-temporal variation in seed production of V. hirundinaria occasionally enforces L. equestris to feed on alternative plant species. We conducted a long-term selection experiment to test if this seed predator is able to adapt to a suboptimal food-plant species in more than 20 generations. We measured fitness and adaptation in terms of increase in reproductive output. We replicated the populations within the selection lines to separate the effects of selection from random drift and conducted intra- and inter-population crosses to detect inbreeding and population differentiation. Furthermore, we analysed how population genetic structure changed during the selection experiment. We found that although the fitness of L. equestris that had fed on the alternative food plant was almost seven times lower than when feeding on V. hirundinaria, it increased significantly during the experiment indicating selection for higher fitness on the alternative food plant. Besides selection, random drift affected adaptation to the alternative food plant as indicated by differences in fitness among the replicate populations. Inter-population crosses within the selection lines resulted to higher fitness than intra-population crosses indicating inbreeding depression. To further underline the negative effects of random drift and inbreeding on adaptive potential of populations, we found that the level of genetic variation was lower in replicate populations feeding on the alternative food plant. Our study is novel in that it combines the analysis of population genetic structure to a more traditional selection experiment to examine host-plant specialization of herbivorous insects.

Abstracts (coauthor)

Interactive effects of inbreeding in a specialized plant-herbivore interaction

Author(s): Kalske, A, Mutikainen P, Muola A, Laukkanen L, Scheepens JF, Leimu R


Inbreeding causes inbreeding depression in plant resistance against herbivores, as well as in several fitness-related traits in the herbivores. Furthermore, plant inbreeding may affect herbivore performance due to reduced herbivore resistance or plant nutritional quality. In many natural plant-herbivore systems, both of the interacting species are likely to experience inbreeding and yet, interactive effects of inbreeding of both a host plant and its herbivore have not been extensively studied. We studied the effects of experimental inbreeding of a perennial host plant, Vincetoxicum hirundinaria, and its specialist herbivore, the moth Abrostola asclepiadis, on plant resistance and herbivore performance in four populations. We were particularly interested in how inbreeding of both the host plant and the herbivore affect host and herbivore inbreeding depression in resistance and performance. Our results demonstrate that the expression of inbreeding depression in herbivore performance depends on whether the herbivore was grown on an inbred or on an outbred host plant and this effect varied among herbivore populations. Inbreeding depression in plants was significantly higher when they were consumed by outbred compared to inbred herbivores. Finally, the expression of inbreeding depression in the host plant in terms of resistance varied among plant and herbivore populations. These findings demonstrate that in plant-herbivore interactions inbreeding depression of one species can be altered depending on the inbreeding of the interacting species. Furthermore, our results suggest that when herbivores are inbred, herbivore-induced selection against self-fertilization in plants may diminish.


Chairman: Octávio S. Paulo
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XIV Congress of the European Society for Evolutionary Biology

Organization Team
Department of Animal Biology (DBA)
Faculty of Sciences of the University of Lisbon
P-1749-016 Lisbon


Computational Biology & Population Genomics Group