Stage‐dependent physiological responses in a butterfly cause non‐additive effects on phenology

Studies illustrating climate‐induced shifts in phenology typically focus on the timing of a single lifecycle stage. In contrast, species’ responses to climate change are likely to be complex and constrained by interactions and tradeoffs across the lifecycle. We characterized the thermal sensitivity of egg, larval and pupal stages of a native Australian butterfly and then integrated these responses to predict sensitivity of emergence time, survival, and feeding performance on oviposition date and climate. Thermal physiology varied among lifecycle stages and between sexes, with the development rate of eggs, first instar larvae, and pupae being the most sensitive to temperature. As lifecycle stages have different thermal physiologies, the environment experienced by a given stage depends in a complex way on the experience of previous stages. Our simulations indicate that oviposition date strongly influences time spent in each lifecycle‐stage, as well as performance. Under a high emissions climate warming scenario (CSIRO Mk 3.5 climate model, high emissions SRES marker scenario A1F1, and a moderate rate of global warming), we predict development times to decrease by 38 days by 2070. Our analysis illustrates how differences in thermal physiology across the lifecycle may result in non‐additive effects on phenology which, in turn, may constrain species’ responses to global warming. These results highlight the need to view shifts in phenology in the context of an organism's entire lifecycle.     

A specific cognitive deficit within semantic cognition across a multi-generational family

We report a study of eight members of a single family (aged 8-72 years), who all show a specific deficit in linking semantic knowledge to language. All affected members of the family had high levels of overall intelligence; however, they had profound difficulties in prose and sentence recall, listening comprehension and naming. The behavioural deficit was remarkably consistent across affected family members. Structural neuroimaging data revealed grey matter abnormalities in the left infero-temporal cortex and fusiform gyri: brain areas that have been associated with integrative semantics. This family demonstrates, to our knowledge, the first example of a heritable, highly specific abnormality affecting the interface between language and cognition in humans and has important implications for our understanding of the genetic basis of cognition.     

Intron splice sites of Papilio glaucus PglRh3 corroborate insect opsin phylogeny

Full-length cDNA clones encoding the PglRh3 opsin from the tiger swallowtail butterfly Papilio glaucus were isolated from cDNA synthesized from adult head tissue total RNA. This cDNA consists of 1679 nucleotides and contains a single open reading frame predicted to be 379 amino acids in length. PCR amplification of genomic DNA with primers spanning the coding region yielded a single 2760bp fragment which was sequenced. The PglRh3 gene has nine exons and eight introns, four of which are in unique locations relative to the positions of introns in other known insect opsin sequences. Phylogenetic analyses of amino acid and nucleotide sequence data places PglRh3 within a clade of insect visual pigments thought to be sensitive to long wavelengths of light. The genomic structure of PglRh3 is the first characterized from a member of this opsin clade. Three PglRh3 intron positions are shared with Drosophila Rh1, and one of these is also shared with Drosophila Rh2. By contrast, none of the known intron locations in a clade of anciently diverged ultraviolet- and blue-sensitive visual pigments are shared by P. glaucus PglRh3, Drosophila Rh1 or Rh2. The placement of introns within opsin genes therefore independently supports the clustering of a putatively long-wavelength-sensitive clade with a clade of blue-green-sensitive visual pigments.     

Polymerisation stress modelling in acrylic bone cement

Fatigue failure of the cement mantle has been proposed as one of the failure processes contributing to aseptic loosening of cemented joint replacements. It has also been suggested that fatigue failure is dramatically accelerated by residual stress generated during the cement polymerisation process. Previous computational models of the polymerisation process have investigated only the latter part of polymerisation by assuming both instantaneous hardening of the material (a stress locking point) and that all residual stress results from thermal shrinkage after this stress locking point. In this study, finite element models which use the local degree of polymerisation to calculate material properties and shrinkage have been used to predict residual stresses in two models of total hip replacement cement mantles. Results indicate that the final value of cement mantle stress may not be the highest stresses that the cement is subjected to during the polymerisation process. Two models are presented, a 2-dimensional model, which was adapted from a similar model in the literature (Lennon and Prendergast, 2002) and a 3-dimensional concentric-cylinders model. In both cases a chemical kinetics model was used to predict the progress of the polymerisation reaction and a second linear model used to predict cement mechanical properties and density, and so stress generation and volume change, over time. There was good agreement of the results of the 2D model with its counterpart in the literature. For the 3D model, the final residual stress magnitudes and patterns showed good agreement with similar physical and computational models in the literature.