Project description:We combined heritability analysis of larval development rate with a global expression analysis of this phenotype to investigate genotype by environment interactions across three ecologically relevant temperatures in the Glanville fritillary butterfly (Melitaea cinxia). We focused upon the development of final instar caterpillars which is greatly affected by temperature, and during this stage the caterpillars build up most of the resources for adult life. Second generation, lab reared larvae, initially collected from the Åland metapopulation, were reared in standard lab condition until 6th larval instar. At the beginning of the final (7th) instar stage the larvae were separated into of three temperature conditions: Cold treatment (temperature profile: 8°C 18:00-9:59, 14°C 10:00-11:59, 20°C 12:00-15:59 and 14°C 16:00-17:59) Standard treatment (temperature profile: 15°C 17:00-6:59, 18°C 7:00-8:59, 22°C 9:00-10:59 and 26°C 11:00-16:59) Hot treatment (temperature profile: 8°C 20:00-7:59, 15°C 8:00-9:59, 35°C 10:00-17:59 and 15°C 18:00-19:59) The temperature profiles mimic the diurnal thermal variation of the natural habitat (Åland islands) of samples. Cold treatment mimics a cool and cloudy summer, Standard represents an average temperature profile in the Åland islands and Hot treatment mimics an exceptionally hot and sunny summer, with cold night-time temperatures. The experiment contained several larval families (full-sib) of which three were selected for gene expression analysis. Samples were snap-frozen in liquid nitrogen during mid-development (after 6, 5 and 4 days, for Cold, Standard and Hot respectively). Additional larvae from the same treatments were assayed for survival and growth. Gene expression was analyzed using a mixed model approach to identify genes with potential heritable expression variation (variation among families), genes with plastic expression responses (treatment induced changes) and genes with treatment dependent expression that varies among families (family by treatment interactions).
Project description:We combined heritability analysis of larval development rate with a global expression analysis of this phenotype to investigate genotype by environment interactions across three ecologically relevant temperatures in the Glanville fritillary butterfly (Melitaea cinxia). We focused upon the development of final instar caterpillars which is greatly affected by temperature, and during this stage the caterpillars build up most of the resources for adult life. Second generation, lab reared larvae, initially collected from the M-CM-^Eland metapopulation, were reared in standard lab condition until 6th larval instar. At the beginning of the final (7th) instar stage the larvae were separated into of three temperature conditions: Cold treatment (temperature profile: 8M-BM-0C 18:00-9:59, 14M-BM-0C 10:00-11:59, 20M-BM-0C 12:00-15:59 and 14M-BM-0C 16:00-17:59) Standard treatment (temperature profile: 15M-BM-0C 17:00-6:59, 18M-BM-0C 7:00-8:59, 22M-BM-0C 9:00-10:59 and 26M-BM-0C 11:00-16:59) Hot treatment (temperature profile: 8M-BM-0C 20:00-7:59, 15M-BM-0C 8:00-9:59, 35M-BM-0C 10:00-17:59 and 15M-BM-0C 18:00-19:59) The temperature profiles mimic the diurnal thermal variation of the natural habitat (M-CM-^Eland islands) of samples. Cold treatment mimics a cool and cloudy summer, Standard represents an average temperature profile in the M-CM-^Eland islands and Hot treatment mimics an exceptionally hot and sunny summer, with cold night-time temperatures. The experiment contained several larval families (full-sib) of which three were selected for gene expression analysis. Samples were snap-frozen in liquid nitrogen during mid-development (after 6, 5 and 4 days, for Cold, Standard and Hot respectively). Additional larvae from the same treatments were assayed for survival and growth. Gene expression was analyzed using a mixed model approach to identify genes with potential heritable expression variation (variation among families), genes with plastic expression responses (treatment induced changes) and genes with treatment dependent expression that varies among families (family by treatment interactions). Full-sib larvae from three families (N170, N74 and O171) were exposed to three temperature treatments (Cold, Standard and Hot) during final (7th) instar stage. A total of 35 samples were used to analyze family, treatment and family by treatment interactions in gene expression, using a mixed model approach. This included 3 biological replicates in Cold and Hot treatments from each family and 5-6 biological replicates in Standard (5 in O171) per family. Techinal replicates from each family and additional techical replicates in family O171 (including dye swap replicates) were used to assess robustness of the findings.
Project description:We present a genome assembly from an individual male Melitaea cinxia (the Glanville fritillary; Arthropoda; Insecta; Lepidoptera; Nymphalidae). The genome sequence is 499 megabases in span. The complete assembly is scaffolded into 31 chromosomal pseudomolecules, with the Z sex chromosome assembled. Gene annotation of this assembly on Ensembl has identified 13,666 protein coding genes.
Project description:Predicting how climate change affects biotic interactions and their evolution poses a challenge. Plant-insect herbivore interactions are particularly sensitive to climate change, as climate-induced changes in plant quality cascade into the performance of insect herbivores. Whereas the immediate survival of herbivore individuals depends on plastic responses to climate change induced nutritional stress, long-term population persistence via evolutionary adaptation requires genetic variation for these responses. In order to assess the prospects for population persistence under climate change, it is therefore crucial to characterise response mechanisms to climate change induced stressors, and quantify their variability in natural populations. Here, we test developmental and transcriptomic responses to water limitation induced host plant quality change in a Glanville fritillary butterfly (Melitaea cinxia) metapopulation. We combine nuclear magnetic resonance spectroscopy on the plant metabolome, larval developmental assays and an RNA seq analysis of the larval transcriptome. We observed that responses to feeding on water limited plants, in which amino acids and aromatic compounds are enriched, showed marked intrapopulation variation, with individuals of some families performing better on control and others on water limited plants. The transcriptomic responses were concordant with the developmental responses: Families exhibiting opposite developmental responses also produced opposite transcriptomic responses, e.g. in growth associated intracellular signalling. The opposite developmental and transcriptomic responses are associated with between families differences in organic compound catabolism and storage protein production. The results reveal heritable intrapopulation variability in plasticity, suggesting potential for evolutionary responses to drought-induced changes in host plant quality in the Finnish M. cinxia metapopulation.