Search results for "history."

Daphnia invest in sexual reproduction when its relative costs are reduced

2018

The timing of sex in facultatively sexual organisms is critical to fitness, due to the differing demographic consequences of sexual versus asexual reproduction. In addition to the costs of sex itself, an association of sex with the production of dormant life stages also influences the optimal use of sex, especially in environments where resting eggs are essential to survive unfavourable conditions. Here we document population dynamics and the occurrence of sexual reproduction in natural populations of Daphnia magna across their growing season. The frequency of sexually reproducing females and males increased with population density and with decreasing asexual clutch sizes. The frequency of…

Genetic variation in plasticity of life-history traits between Atlantic cod (Gadus morhua) populations exposed to contrasting thermal regimes

2016

We employed common-garden experiments to test for genetic variation in responses of larval life-history traits to temperature between two populations of Atlantic cod (Gadus morhua L., 1758) that naturally experience contrasting thermal environments during early life due to spatial and temporal differences in spawning. Southern Gulf of St. Lawrence cod larvae experienced faster growth in warmer water and low, uniform survival across all experimental temperatures (3, 7, 11 °C), consistent with previous studies on this spring-spawning population. In contrast, larvae from fall-spawning Southwestern Scotian Shelf cod collected near Sambro, Nova Scotia, lacked plasticity for growth but experienc…

Phenological and intrinsic predictors of mite and haemacoccidian infection dynamics in a Mediterranean community of lizards

2021

Ectotherms are vulnerable to environmental changes and their parasites are biological health indicators. Thus, parasite load in ectotherms is expected to show a marked phenology. This study investigates temporal host–parasite dynamics in a lizard community in Eastern Spain during an entire annual activity period. The hosts investigated were Acanthodactylus erythrurus, Psammodromus algirus and Psammodromus edwardsianus, three lizard species coexisting in a mixed habitat of forests and dunes, providing a range of body sizes, ecological requirements and life history traits. Habitat and climate were considered as potential environmental predictors of parasite abundance, while size, body conditi…

Ecological conditions alter cooperative behaviour and its costs in a chemically defended sawfly

2018

The evolution of cooperation and social behaviour is often studied in isolation from the ecology of organisms. Yet, the selective environment under which individuals evolve is much more complex in nature, consisting of ecological and abiotic interactions in addition to social ones. Here, we measured the life-history costs of cooperative chemical defence in a gregarious social herbivore, Diprion pini pine sawfly larvae, and how these costs vary under different ecological conditions. We ran a rearing experiment where we manipulated diet (resin content) and attack intensity by repeatedly harassing larvae to produce a chemical defence. We show that forcing individuals to allocate more to coope…

2021

Predator-induced plasticity in life-history and antipredator traits during the larval period has been extensively studied in organisms with complex life-histories. However, it is unclear whether different levels of predation could induce warning signals in aposematic organisms. Here, we investigated whether predator-simulated handling affects warning coloration and life-history traits in the aposematic wood tiger moth larva, Arctia plantaginis. As juveniles, a larger orange patch on an otherwise black body signifies a more efficient warning signal against predators but this comes at the costs of conspicuousness and thermoregulation. Given this, one would expect that an increase in predation…

Highly contrasted population genetic structures in a host-parasite pair in the Caribbean Sea.

2017

Evolution and population genetic structure of marine species across the Caribbean Sea are shaped by two complex factors: the geological history and the present pattern of marine currents. Characterizing and comparing the genetic structures of codistributed species, such as host–parasite associations, allow discriminating the relative importance of environmental factors and life history traits that influenced gene flow and demographic events. Using microsatellite and Cytochrome Oxidase I markers, we investigated if a host–parasite pair (the heart urchin Meoma ventricosa and its parasitic pea crab Dissodactylus primitivus) exhibits comparable population genetic structures in the Caribbean Sea…

Evolutionary history and species delimitations:a case study of the hazel dormouse, Muscardinus avellanarius

2017

Robust identification of species and significant evolutionary units (ESUs) is essential to implement appropriate conservation strategies for endangered species. However, definitions of species or ESUs are numerous and sometimes controversial, which might lead to biased conclusions, with serious consequences for the management of endangered species. The hazel dormouse, an arboreal rodent of conservation concern throughout Europe is an ideal model species to investigate the relevance of species identification for conservation purposes. This species is a member of the Gliridae family, which is protected in Europe and seriously threatened in the northern part of its range. We assessed the exten…

Infection, specificity and host manipulation of Australapatemon sp. (Trematoda, Strigeidae) in two sympatric species of leeches (Hirudinea)

2017

SUMMARYFactors that drive parasite specificity and differences in infection dynamics among alternative host species are important for ecology and evolution of host–parasite interactions, but still often poorly known in natural systems. Here, we investigated spatiotemporal dynamics of infection, host susceptibility and parasite-induced changes in host phenotype in a rarely explored host–parasite system, theAustralapatemonsp. trematode infecting two sympatric species of freshwater leeches,Erpobdella octoculataandHelobdella stagnalis. We show significant variation in infection abundance between the host species in both space and time. Using experimental infections, we also show that most of th…

Adaptation to environmental stress at different timescales

2020

Environments are changing rapidly, and to cope with these changes, organisms have to adapt. Adaptation can take many shapes and occur at different speeds, depending on the type of response, the trait, the population, and the environmental conditions. The biodiversity crisis that we are currently facing illustrates that numerous species and populations are not capable of adapting with sufficient speed to ongoing environmental changes. Here, we discuss current knowledge on the ability of animals and plants to adapt to environmental stress on different timescales, mainly focusing on thermal stress and ectotherms. We discuss within-generation responses that can be fast and induced within minute…

Genomic Differentiation and Demographic Histories of Atlantic and Indo-Pacific Yellowfin Tuna (Thunnus albacares) Populations.

2017

Recent developments in the field of genomics have provided new and powerful insights into population structure and dynamics that are essential for the conservation of biological diversity. As a commercially highly valuable species, the yellowfin tuna (Thunnus albacares) is intensely exploited throughout its distribution in tropical oceans around the world, and is currently classified as near threatened. However, conservation efforts for this species have so far been hampered by limited knowledge of its population structure, due to incongruent results of previous investigations. Here, we use whole-genome sequencing in concert with a draft genome assembly to decipher the global population str…