Biology subjects

Opedal, O. H.

Publications and source records attributed to Opedal, O. H..

4 recordsLinked to original sources

bioRxiv2025

Can evolutionary potential help plants survive climate change? High variability in evolvability and G-matrix structure of Hypericum populations

2To predict the consequences of global change, we need knowledge of the ability of populations to evolve. On the short term, this is driven by the amount of standing genetic variation in the population. There is a pressing need for empirical data on evolutionary potential of natural populations, and on how evolutionary potential varies among species and across species distributions. Here, we evaluate and compare additive genetic variance-covariance matrices (G-matrices) and evolutionary potential in multiple populations of two Hypericum species, one of them a generalist perennial plant with a wide geographic distribution, and the other a rare habitat specialist. With these comparisons, we aim to evaluate the stability of the G-matrix within and among plant species, and whether the genetic architecture of some plant trait modules remains more stable than of others. We utilize manual crossing experiments in a nested half-sibling breeding design and quantitative genetic analyses to estimate evolvabilities (mean-scaled genetic variances) as a proportional measure of evolutionary potential. With such comparisons of evolvability in different types of species and populations, we can begin to understand general patterns in the variation of evolutionary potential in nature.

evolutionary biology↗

bioRxiv2022

Linking microenvironment modification to species interactions and demography in an alpine plant community

Individual plants can modify the microenvironment within their spatial neighborhood. However, the consequences of microenvironment modification for demography and species interactions remain unclear at the community scale. In a study of co-occurring alpine plants, we (1) determined the extent of species-specific microclimate modification by comparing temperature and soil moisture between vegetated and non-vegetated microsites for several focal species. We (2) determined how vital rates (survival, growth, fecundity) of all species varied in response to aboveground and belowground vegetative overlap with inter- and intraspecific neighbors as proxies for microenvironment modification. For (1), surface temperatures were buffered (lower maximums and higher minimums) and soil moisture was higher below the canopies of most species compared to non-vegetated areas. For (2), vegetative overlap predicted most vital rates, although the effect varied depending on whether aboveground or belowground overlap was considered. Vital rate response to microenvironment-modification proxies (vegetative overlap) was also frequently context dependent with respect to plant size and macroclimate. Microenvironment modification and spatial overlapping of individuals are key drivers of demography and species interactions in this alpine community.

ecology↗

bioRxiv2022

Seasonality and competition select for variable germination behavior in perennials

The common occurrence of within-population variation in germination behavior and associated traits such as seed size has long fascinated evolutionary ecologists. In annuals, unpredictable environments are known to select for bet-hedging strategies causing variation in dormancy duration and germination strategies. Variation in germination timing and associated traits is also commonly observed in perennials, and often tracks gradients of environmental predictability. Although bet-hedging is thought to occur less frequently in long-lived organisms, these observations suggest a role of bet-hedging strategies in perennials occupying unpredictable environments. We use complementary analytical and evolutionary simulation models of within-individual variation in germination behavior in seasonal environments to show how bet-hedging interacts with fluctuating selection, life-history traits, and competitive asymmetries among germination strategies. We reveal substantial scope for bet-hedging to produce variation in germination behavior in long-lived plants, when false starts to the growing season results in either competitive advantages or increased mortality risk for alternative germination strategies. Additionally, we find that lowering adult survival may, in contrast to classical bet-hedging theory, result in less spreading of germination by decreasing density-dependent competition. These models extend insights from bet-hedging theory to perennials and explore how competitive communities may be affected by ongoing changes in climate and seasonality patterns.

evolutionary biology↗

bioRxiv2020

High evolutionary potential in the chemical defenses of an aposematic Heliconius butterfly

Chemical defences against predators underlie the evolution of aposematic coloration and mimicry, which are classic examples of adaptive evolution. Surprisingly little is known about the roles of ecological and evolutionary processes maintaining defence variation, and how they may feedback to shape the evolutionary dynamics of species. Cyanogenic Heliconius butterflies exhibit diverse warning color patterns and mimicry, thus providing a useful framework for investigating these questions. We studied intraspecific variation in de novo biosynthesized cyanogenic toxicity and its potential ecological and evolutionary sources in wild populations of Heliconius erato along environmental gradients, in common-garden broods and with feeding treatments. Our results demonstrate substantial intraspecific variation, including detectable variation among broods reared in a common garden. The latter estimate suggests considerable evolutionary potential in this trait, although predicting the response to selection is likely complicated due to the observed skewed distribution of toxicity values and the signatures of maternal contributions to the inheritance of toxicity. Larval diet contributed little to toxicity variation. Furthermore, toxicity profiles were similar along steep rainfall and altitudinal gradients, providing little evidence for these factors explaining variation in biosynthesized toxicity in natural populations. In contrast, there were striking differences in the chemical profiles of H. erato from geographically distant populations, implying potential local adaptation in the acquisition mechanisms and levels of defensive compounds. The results highlight the extensive variation and potential for adaptive evolution in defense traits for aposematic and mimetic species, which may contribute to the high diversity often found in these systems.

evolutionary biology↗