Whether sexual selection generally promotes or impedes population persistence remains an open question. Intralocus sexual conflict (IaSC) can render sexual selection in males detrimental to the population by increasing the frequency of alleles with positive effects on male reproductive success but negative effects on female fecundity. Recent modeling based on fitness landscape theory, however, indicates that the relative impact of IaSC may be reduced in maladapted populations and that sexual selection therefore might promote adaptation when it is most needed. Here, we test this prediction using bean beetles that had undergone 80 generations of experimental evolution on two alternative host plants. We isolated and assessed the effect of maladaptation on sex-specific strengths of selection and IaSC by cross-rearing the two experimental evolution regimes on the alternative hosts and estimating within-population genetic (co)variance for fitness in males and females. Two key predictions were upheld: males generally experienced stronger selection compared to females and maladaptation increased selection in females. However, maladaptation consistently decreased male-bias in the strength of selection and IaSC was not reduced in maladapted populations. These findings imply that sexual selection can be disrupted in stressful environmental conditions, thus reducing one of the potential benefits of sexual reproduction in maladapted populations.

The role of mitochondrial DNA for the evolution of life-history traits remains debated. We examined mitonuclear effects on the activity of the multisubunit complex of the electron transport chain (ETC) involved in oxidative phosphorylation (OXPHOS) across lines of the seed beetle Acanthoscelides obtectus selected for a short (E) or a long (L) life for more than >160 generations. We constructed and phenotyped mitonuclear introgression lines, which allowed us to assess the independent effects of the evolutionary history of the nuclear and the mitochondrial genome. The nuclear genome was responsible for the largest share of divergence seen in ageing. However, the mitochondrial genome also had sizeable effects, which were sex-specific and expressed primarily as epistatic interactions with the nuclear genome. The effects of mitonuclear disruption were largely consistent with mitonuclear coadaptation. Variation in ETC activity explained a large proportion of variance in ageing and life-history traits and this multivariate relationship differed somewhat between the sexes. In conclusion, mitonuclear epistasis has played an important role in the laboratory evolution of ETC complex activity, ageing, and life histories and these are closely associated. The mitonuclear architecture of evolved differences in life-history traits and mitochondrial bioenergetics was sex-specific.

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Background Investigations of evolution knowledge and acceptance and their relation are central to evolution education research. Ambiguous results in this field of study demonstrate a variety of measuring issues, for instance differently theorized constructs, or a lack of standardized methods, especially for cross-country comparisons. In particular, meaningful comparisons across European countries, with their varying cultural backgrounds and education systems, are rare, often include only few countries, and lack standardization. To address these deficits, we conducted a standardized European survey, on 9200 first-year university students in 26 European countries utilizing a validated, comprehensive questionnaire, the “Evolution Education Questionnaire”, to assess evolution acceptance and knowledge, as well as influencing factors on evolution acceptance. Results We found that, despite European countries’ different cultural backgrounds and education systems, European first-year university students generally accept evolution. At the same time, they lack substantial knowledge about it, even if they are enrolled in a biology-related study program. Additionally, we developed a multilevel-model that determines religious faith as the main influencing factor in accepting evolution. According to our model, knowledge about evolution and interest in biological topics also increase acceptance of evolution, but to a much lesser extent than religious faith. The effect of age and sex, as well as the country’s affiliation, students’ denomination, and whether or not a student is enrolled in a biology-related university program, is negligible. Conclusions Our findings indicate that, despite all their differences, most of the European education systems for upper secondary education lead to acceptance of evolution at least in university students. It appears that, at least in this sample, the differences in knowledge between countries reflect neither the extent to which school curricula cover evolutionary biology nor the percentage of biology-related students in the country samples. Future studies should investigate the role of different European school curricula, identify particularly problematic or underrepresented evolutionary concepts in biology education, and analyze the role of religious faith when teaching evolution.

Expansion of the host range in phytophagous insects depends on their ability to form an association with a novel plant through changes in host-related traits. Phenotypic plasticity has important effects on initial survival of individuals faced with a new plant, as well as on the courses of evolutionary change during long-term adaptation to novel conditions. Using experimental populations of the seed beetle that evolved on ancestral (common bean) or novel (chickpea) host and applying reciprocal transplant at both larval and adult stage on the alternative host plant, we studied the relationship between the initial (plastic) phases of host-shift and the subsequent stages of evolutionary divergence in life-history strategies between populations exposed to the host-shift process. After 48 generations, populations became well adapted to chickpea by evolving the life-history strategy with prolonged larval development, increased body mass, earlier reproduction, shorter lifespan and decreased plasticity of all traits compared with ancestral conditions. In chickpea-adapted beetles, negative fitness consequences of low plasticity of pre-adult development (revealed as severe decrease in egg-to-adult viability on beans) exhibited mismatch with positive effects of low plasticity (i.e. low host sensitivity) in oviposition and fecundity. In contrast, beetles adapted to the ancestral host showed high plasticity of developmental process, which enabled high larval survival on chickpea, whereas elevated plasticity in adult behaviour (i.e. high host sensitivity) resulted in delayed reproduction and decreased fecundity on chickpea. The analysis of population growth parameters revealed significant fluctuation during successive phases of the host-shift process in A. obtectus.

Products and regulatory motifs of the mitochondrial and nuclear genomes interact closely to enable efficient cellular energy production within mitochondria. Although recent evidences support the prediction that during evolutionary time combinations of these interactions are optimized by selection acting on important life history traits, relatively few studies have directly tested it. The goal of this study was to test the role of mitonuclear interactions in shaping preadult and adult life history traits under age-specific selection in the seed beetle (Acanthoscelides obtectus). In order to disentangle the effects of mitochondria, nuclei and their interaction in the evolutionary response to the long-term laboratory selection for early (E) and late (L) reproduction, we used mitonuclear introgression lines in which E and L mitochondrial genomes were expressed in both E and L nuclear background. We found that mitonuclear genotypes carrying disrupted pair of nuclear and mitochondrial genomes mainly affected preadult life history traits-egg-to-adult viability and developmental time. Neither mitochondria nor their interaction with nuclear genomes had effects on realized fecundity of mated females and longevity of virgin beetles. However, when involved in reproductive activities females and males with disrupted genotypes mostly exhibited reduced longevity. Furthermore, since reproduced males exhibited greater longevity cost than females, our results are in accordance with the mother's curse hypothesis. Being that for the most life history traits we detected smaller additive mitochondrial genetic effects compared with epistatic mitonuclear effects, we concluded that mitonuclear interactions might be the target of age-specific selection.

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Mitochondria play a key role in ageing. The pursuit of genes that regulate variation in life span and ageing have shown that several nuclear-encoded mitochondrial genes are important. However, the role of mitochondrial encoded genes (mtDNA) is more controversial and our appreciation of the role of mtDNA for the evolution of life span is limited. We use replicated lines of seed beetles that have been artificially selected for long or short life for>190 generations, now showing dramatic phenotypic differences, to test for a possible role of mtDNA in the divergent evolution of ageing and life span. We show that these divergent selection regimes led to the evolution of significantly different mtDNA haplotype frequencies. Selection for a long life and late reproduction generated positive selection for one specific haplotype, which was fixed in most such lines. In contrast, selection for reproduction early in life led to both positive selection as well as negative frequency-dependent selection on two different haplotypes, which were both present in all such lines. Our findings suggest that the evolution of life span was in part mediated by mtDNA, providing support for the emerging general tenet that adaptive evolution of life-history syndromes may involve mtDNA.