Search results for "jälkeläiset"
showing 5 items of 5 documents
Hybridization selects for prime‐numbered life cycles in Magicicada: An individual‐based simulation model of a structured periodical cicada population
2020
Abstract We investigate competition between separate periodical cicada populations each possessing different life‐cycle lengths. We build an individual‐based model to simulate the cicada life cycle and allow random migrations to occur between patches inhabited by the different populations. We show that if hybridization between different cycle lengths produces offspring that have an intermediate life‐cycle length, then predation acts disproportionately to select against the hybrid offspring. This happens because they emerge in low densities without the safety‐in‐numbers provided by either parent population. Thus, prime‐numbered life cycles that can better avoid hybridization are favored. How…
Variation in egg size and offspring phenotype among and within seven Arctic charr morphs.
2022
Maternal effects have the potential to alter early developmental processes of offspring and contribute to adaptive diversification. Egg size is a major contributor to offspring phenotype, which can influence developmental trajectories and potential resource use. However, to what extent intraspecific variation in egg size facilitates evolution of resource polymorphism is poorly understood. We studied multiple resource morphs of Icelandic Arctic charr, ranging from an anadromous morph—with a phenotype similar to the proposed ancestral phenotype—to sympatric morphs that vary in their degree of phenotypic divergence from the ancestral anadromous morph. We characterized variation in egg size and…
Individual- and group-level sex ratios under local mate competition : consequences of infanticide and reproductive dominance
2023
Extremely female-biased sex ratios of parasitoid wasps in multiple-foundress groups challenges evolutionary theory which predicts diminishing bias as foundress numbers increase. Recent theory based on foundress cooperation has achieved qualitative rather than quantitative success in explaining bias among parasitoids in the genus Sclerodermus. Here, we develop an explanation, expanding the theory of local mate competition, based on the observation that male production seems dominated by some foundresses within groups. Two sex ratio effects arise from such reproductive dominance: an immediate effect via suppression of male production, and a long-term evolutionary response to reproductive skew…
Early life of fathers affects offspring fitness in a wild rodent
2019
Intergenerational fitness effects on offspring due to the early life of the parent are well studied from the standpoint of the maternal environment, but intergenerational effects owing to the paternal early life environment are often overlooked. Nonetheless, recent laboratory studies in mammals and ecologically relevant studies in invertebrates predict that paternal effects can have a major impact on the offspring's phenotype. These non‐genetic, environment‐dependent paternal effects provide a mechanism for fathers to transmit environmental information to their offspring, and could allow rapid adaptation. We used the bank vole Myodes glareolus, a wild rodent species with no paternal care, t…
Maternal effects in the magpie
2006
Marjo Pihlaja tutki väitöskirjatyössään äitivaikutusten merkitystä sopeumana vaihteleviin ympäristöoloihin käyttäen tutkimuslajina luonnonvaraisena pesiviä harakoita. Äitivaikutuksiin kuuluvat äidiltä jälkeläisille siirtyvät ympäristön äidille aiheuttamat ilmiasun piirteet sekä emon jakamien resurssien vaikutukset jälkeläisten ilmiasuun. Pihlaja tutki lintuja, mutta monet hänen tutkimansa mekanismit toimivat myös nisäkkäillä – siis myös ihmisillä.Pihlajan tavoitteena oli selvittää, peilaako munassa olevien yhdisteiden määrä vain emon kuntoa pesimäkauden alussa ja muninnan aikana, vai voiko näiden poikaselle tarjolla olevien yhdisteiden määrän vaihtelun takana olla myös evolutiivisesti merki…