Maternal and paternal sugar consumption interact to modify offspring life history and physiology

First published: 09 March 20221. Intergenerational effects on offspring phenotypes occur in response to variation in both maternal and paternal nutrition. Because the combined maternal and paternal effects are rarely considered together, however, their relative contributions, and the capacity for interactions between parental diets to shape offspring life history and physiology are not understood. 2. To address this, we altered the sucrose levels of adult fruit flies (Drosophila melanogaster) prior to mating, across two generations, producing parent–parent and parent–offspring combinations that were either matched or mismatched in dietary sucrose. We then measured life span, fecundity, body mass and triglyceride levels in parents and offspring. 3. We reveal complex, non-cumulative interactions, which involve diets of each parent and offspring, shape offspring phenotypes, but the effects were generally not consistent with an adaptive response to parental diet. 4. Notably, we find that interacting parental flies (sires and dams) lived longer when their sucrose treatments were matched, but they produced shorter lived offspring. 5. These results are suggestive of intergenerational conflict over optimal diets, and call for further research into the capacity, and mechanisms, for mismatches in parental environments to enhance offspring phenotype generally. 6. Our study also indicates that studies of maternal and paternal effects will need embrace experimental designs with power to test for interactions between maternal and paternal environments if they are to fully understand the ecological and evolutionary significance of parental effects on offspring fitness.Tara-Lyn Camilleri, Matthew D. W. Piper, Rebecca L. Robker, Damian K. Dowlin

The costs of being male: are there sex-specific effects of uniparental mitochondrial inheritance?

Eukaryotic cells typically contain numerous mitochondria, each with multiple copies of their own genome, the mtDNA. Uniparental transmission of mitochondria, usually via the mother, prevents the mixing of mtDNA from different individuals. While on the one hand, this should resolve the potential for selection for fast-replicating mtDNA variants that reduce organismal fitness, maternal inheritance will, in theory, come with another set of problems that are specifically relevant to males. Maternal inheritance implies that the mitochondrial genome is never transmitted through males, and thus selection can target only the mtDNA sequence when carried by females. A consequence is that mtDNA mutations that confer male-biased phenotypic expression will be prone to evade selection, and accumulate. Here, we review the evidence from the ecological, evolutionary and medical literature for male specificity of mtDNA mutations affecting fertility, health and ageing. While such effects have been discovered experimentally in the laboratory, their relevance to natural populations—including the human population—remains unclear. We suggest that the existence of male expression-biased mtDNA mutations is likely to be a broad phenomenon, but that these mutations remain cryptic owing to the presence of counter-adapted nuclear compensatory modifier mutations, which offset their deleterious effect

No effects of a feather mite on life-history components and grooming behaviour in the Seychelles warbler, Acrocephalus sechellensis.

A common assumption of studies examining host-symbiont interactions is that all symbiotic organisms are parasitic. Feather mites are widespread symbionts of birds that do not appear to deplete the host of any vital resources. Instead they feed on the oily secretions that cover the feathers and the detritus caught in these secretions. Therefore, a more logical assumption might be that feather mites are non-parasitic. We investigated whether infestation by a feather mite, Trouessartia sp. (Trouessartiidae), has any detrimental effects on the Seychelles warbler, Acrocephalus sechellensis. Feather mite load was not correlated with body condition. Survivorship of birds per territory was lower for birds with lower mite loads, but this result is explained by these birds also living in low-quality territories with low food availability. The amount of time birds spent grooming was not related to feather mite load and grooming did not decrease following the experimental removal of mites. Additionally, although males groom more than females, they do not have larger mite loads than females. Although this study is largely non-experimental, the combined results indicate that the relationship between these feather mites and the Seychelles warbler is probably benign

ORIC central region calculations

The central region for the K = 100 Oak Ridge Isochronous Cyclotron, ORIC, will be modified to provide better orbit centering, focusing of orbits in the axial direction, and phase selection, in order to improve extraction efficiency, and reduce radioactive activation of cyclotron components. The central region is specifically designed for the acceleration of intense light ion beams such as 60 MeV protons and 15--100 MeV alphas. These beams will be used in the production of radioactive atoms in the Radioactive Ion Beam Project at Oak Ridge National Laboratory