scholarly journals Density-by-diet interactions during larval development shape adult life-history trait expression and fitness in a polyphagous fly

2022 ◽  
Author(s):  
Juliano Morimoto ◽  
Anh The Than ◽  
Binh Nguyen ◽  
Ida Lundbäck ◽  
Hue Dinh ◽  
...  
2021 ◽  
Author(s):  
Juliano Morimoto ◽  
Anh The Than ◽  
Binh Nguyen ◽  
Ida Lundback ◽  
Hue Dinh ◽  
...  

Habitat quality early in life determines individual fitness, with possible long-term evolutionary effects on groups and populations. In holometabolous insects, larval ecology plays a major role in determining the expression of traits in adulthood, but how ecological conditions during larval stage interact to shape adult life-history and fitness, particularly in non-model organisms, remains subject to scrutiny. Consequently, our knowledge of the interactive effects of ecological factors on insect development is limited. Here, using the polyphagous fly Bactrocera tryoni, we conducted a fully-factorial design where we manipulated larval density and larval diet (protein-rich, standard, and sugar-rich) to gain insights into how these ecological factors interact to modulate adult fitness. As expected, a protein-rich diet resulted in faster larval development, heavier and leaner adults that were more fecund compared with standard and sugar-rich diets, irrespective of larval density. Females from the protein-rich larval diet had overall higher reproductive rate (i.e., eggs per day) than females from other diets, and reproductive rate decreased linearly with density for females from the protein-rich but non-linearly for females from the standard and sugar-rich diets over time. Surprisingly, adult lipid reserve increased with larval density for adults from the sugar-rich diet (as opposed to decreasing, as in other diets), possibly due to a stress-response to an extremely adverse condition during development (i.e., high intraspecific competition and poor nutrition). Together, our results provide insights into how ecological factors early in life interact and shape the fate of individuals through life-stages in holometabolous insects.


2021 ◽  
Author(s):  
Anik Dutta ◽  
Fanny E. Hartmann ◽  
Carolina Sardinha Francisco ◽  
Bruce A. McDonald ◽  
Daniel Croll

AbstractThe adaptive potential of pathogens in novel or heterogeneous environments underpins the risk of disease epidemics. Antagonistic pleiotropy or differential resource allocation among life-history traits can constrain pathogen adaptation. However, we lack understanding of how the genetic architecture of individual traits can generate trade-offs. Here, we report a large-scale study based on 145 global strains of the fungal wheat pathogen Zymoseptoria tritici from four continents. We measured 50 life-history traits, including virulence and reproduction on 12 different wheat hosts and growth responses to several abiotic stressors. To elucidate the genetic basis of adaptation, we used genome-wide association mapping coupled with genetic correlation analyses. We show that most traits are governed by polygenic architectures and are highly heritable suggesting that adaptation proceeds mainly through allele frequency shifts at many loci. We identified negative genetic correlations among traits related to host colonization and survival in stressful environments. Such genetic constraints indicate that pleiotropic effects could limit the pathogen’s ability to cause host damage. In contrast, adaptation to abiotic stress factors was likely facilitated by synergistic pleiotropy. Our study illustrates how comprehensive mapping of life-history trait architectures across diverse environments allows to predict evolutionary trajectories of pathogens confronted with environmental perturbations.


Author(s):  
Gaotian Zhang ◽  
Jake D Mostad ◽  
Erik C Andersen

Abstract Life history traits underlie the fitness of organisms and are under strong natural selection. A new mutation that positively impacts a life history trait will likely increase in frequency and become fixed in a population (e.g. a selective sweep). The identification of the beneficial alleles that underlie selective sweeps provides insights into the mechanisms that occurred during the evolution of a species. In the global population of Caenorhabditis elegans, we previously identified selective sweeps that have drastically reduced chromosomal-scale genetic diversity in the species. Here, we measured the fecundity of 121 wild C. elegans strains, including many recently isolated divergent strains from the Hawaiian islands and found that strains with larger swept genomic regions have significantly higher fecundity than strains without evidence of the recent selective sweeps. We used genome-wide association (GWA) mapping to identify three quantitative trait loci (QTL) underlying the fecundity variation. Additionally, we mapped previous fecundity data from wild C. elegans strains and C. elegans recombinant inbred advanced intercross lines that were grown in various conditions and detected eight QTL using GWA and linkage mappings. These QTL show the genetic complexity of fecundity across this species. Moreover, the haplotype structure in each GWA QTL region revealed correlations with recent selective sweeps in the C. elegans population. North American and European strains had significantly higher fecundity than most strains from Hawaii, a hypothesized origin of the C. elegans species, suggesting that beneficial alleles that caused increased fecundity could underlie the selective sweeps during the worldwide expansion of C. elegans.


1974 ◽  
Vol 106 (4) ◽  
pp. 367-376 ◽  
Author(s):  
W. W. Sawchyn ◽  
C. Gillott

AbstractLestes congener Hagen overwinters in the egg stage. There is a diapause just before blastokinesis, during which the egg is extremely resistant to low temperatures and desiccation. Post-diapause embryonic development can occur near 0 °C but will not take place until the eggs are wetted as the pond habitat fills in the spring. Hatching does not occur until the temperature exceeds about 5 °C and is highly synchronous. Larval development is rapid and is completed in the field in about 50 days. Emergence of the adults also is synchronous. Sexual maturation requires 3 weeks. Oviposition occurs immediately after copulation while the pair are still in tandem. It takes place only in dry stems of Scirpus. Adaptations of L. congener for life under rigorous prairie conditions are discussed.


2018 ◽  
Author(s):  
Jacob W. Malcom ◽  
Thomas E. Juenger ◽  
Mathew A. Leibold

ABSTRACTBackgroundIdentifying the molecular basis of heritable variation provides insight into the underlying mechanisms generating phenotypic variation and the evolutionary history of organismal traits. Life history trait variation is of central importance to ecological and evolutionary dynamics, and contemporary genomic tools permit studies of the basis of this variation in non-genetic model organisms. We used high density genotyping, RNA-Seq gene expression assays, and detailed phenotyping of fourteen ecologically important life history traits in a wild-caught panel of 32Daphnia pulexclones to explore the molecular basis of trait variation in a model ecological species.ResultsWe found extensive phenotypic and a range of heritable genetic variation (~0 < H2< 0.44) in the panel, and accordingly identify 75-261 genes—organized in 3-6 coexpression modules—associated with genetic variation in each trait. The trait-related coexpression modules possess well-supported promoter motifs, and in conjunction with marker variation at trans- loci, suggest a relatively small number of important expression regulators. We further identify a candidate genetic network with SNPs in eight known transcriptional regulators, and dozens of differentially expressed genes, associated with life history variation. The gene-trait associations include numerous un-annotated genes, but also support several a priori hypotheses, including an ecdysone-induced protein and several Gene Ontology pathways.ConclusionThe genetic and gene expression architecture ofDaphnialife history traits is complex, and our results provide numerous candidate loci, genes, and coexpression modules to be tested as the molecular mechanisms that underlieDaphniaeco-evolutionary dynamics.


1993 ◽  
Vol 71 (3) ◽  
pp. 568-578 ◽  
Author(s):  
D. Dudley Williams ◽  
Annette Tavares-Cromar ◽  
Donn J. Kushner ◽  
John R. Coleman

The relationship between the biology and habitat of larval mosquitoes was studied in a series of artificial ponds of differing characteristics established across a terrestrial vegetation gradient from open fields to deep woods. The ponds were uniformly colonized by two widespread species of Culex, both characteristic of small bodies of water, including artificial, "container" habitats. First-instar larvae of Culex restuans were found within 2 days of filling the ponds with water and four or five generations were produced from May until the end of September. One very long generation occurred in July, which corresponded to maximum larval densities. Overall, there was a strong relationship between larval development time of C. restuans and larval density. A few larvae of Culex pipiens pipiens occurred sporadically throughout the summer, but numbers did not increase until C. restuans populations began to wane in late July. Thereafter two, or possibly three, generations were produced into the autumn. The patterns of colonization, synchrony of life history, and growth of these two species were remarkably consistent amongst the ponds, despite considerable variation in both their physical and biological environments (e.g., over the 2 years of study, conductivity ranged from 20 to 890 μS, pH from 6.4 to 10.7, dissolved oxygen from 0 to 13.5 ppm, and water temperature from 5 to 29.8 °C). Density of C. restuans was related to water temperature and pH at the "open" site and to water temperature, dissolved oxygen, percent algae, and percent detritus at the "edge of the woods" site. At the "deep woods" site, larval numbers were related to temperature, pH, conductivity, and dissolved oxygen. At both the edge and deep wood sites, larval development time of C. restuans increased with mean water temperature to 20 °C. Above this temperature, larval development time tended to decrease.


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