Nepotistic nosiness: inclusive fitness and vigilance of kin members' romantic relationships

The logic of inclusive fitness suggests that people should be attentive to the mating relationships of their kin—especially their genetically closest kin. This logic further suggests that people will be especially attentive to close kin members' relationships when a greater indirect fitness benefit is at stake. Three studies tested implications of this analysis. The primary results were that (a) people maintain greater vigilance over (and attempt greater influence on) the romantic relationships of genetically closer kin; (b) this effect is largely mediated by feelings of emotional closeness and perceptions of physical similarity; (c) women are more vigilant than men over their kin members' relationships; (d) people are more vigilant over the relationships of female kin, as compared to male kin, but only under conditions with especially clear implications for indirect fitness; and (e) people are more vigilant over kin members' long-term committed relationships, as compared to their casual relationships. These results indicate that a subtle form of nepotism is manifest in people's concern with their kin members' romantic relationships.     

Reimagining the wilderness ethic to include “people and nature”

Biodiversity and Conservation - The concept of the “wilderness ethic” is at an impasse. Despite calls for action to conserve wilderness, any notion of wilderness thinking still resides...     

Modelling temperature-driven changes in species associations across freshwater communities

Due to global climate change–induced shifts in species distributions, estimating changes in community composition through the use of Species Distribution Models has become a key management tool. Being able to determine how species associations change along environmental gradients is likely to be pivotal in exploring the magnitude of future changes in species’ distributions. This is particularly important in connectivity-limited ecosystems, such as freshwater ecosystems, where increased human translocation is creating species associations over previously unseen environmental gradients. Here, we use a large-scale presence–absence dataset of freshwater fish from lakes across the Fennoscandian region in a Joint Species Distribution Model, to measure the effect of temperature on species associations. We identified a trend of negative associations between species tolerant of cold waters and those tolerant of warmer waters, as well as positive associations between several more warm-tolerant species, with these associations often shifting depending on local temperatures. Our results confirm that freshwater ecosystems can expect to see a large-scale shift towards communities dominated by more warm-tolerant species. While there remains much work to be done to predict exactly where and when local extinctions may take place, the model implemented provides a starting-point for the exploration of climate-driven community trends. This approach is especially informative in regards to determining which species associations are most central in shaping future community composition, and which areas are most vulnerable to local extinctions.     

The phytochemical polydatin ameliorates non‐alcoholic steatohepatitis by restoring lysosomal function and autophagic flux

Impaired autophagic degradation of intracellular lipids is causally linked to the development of non‐alcoholic steatohepatitis (NASH). Pharmacological agents that can restore hepatic autophagic flux could therefore have therapeutic potentials for this increasingly prevalent disease. Herein, we investigated the effects of polydatin, a natural precursor of resveratrol, in a murine nutritional model of NASH and a cell line model of steatosis. Results showed that oral administration of polydatin protected against hepatic lipid accumulation and alleviated inflammation and hepatocyte damage in db/db mice fed methionine‐choline deficient diet. Polydatin also alleviated palmitic acid‐induced lipid accumulation in cultured hepatocytes. In both models, polydatin restored lysosomal function and autophagic flux that were impaired by NASH or steatosis. Mechanistically, polydatin inhibited mTOR signalling and up‐regulated the expression and activity of TFEB, a known master regulator of lysosomal function. In conclusion, polydatin ameliorated NASH through restoring autophagic flux. The polydatin‐regulated autophagy was associated with inhibition of mTOR pathway and restoration of lysosomal function by TFEB. Our study provided affirmative preclinical evidence to inform future clinical trials for examining the potential anti‐NASH effect of polydatin in humans.     

Translational optical coherence elastography for assessment of systemic sclerosis

Systemic sclerosis (SSc‐scleroderma) is an autoimmune disorder with high mortality rate that results in excessive accumulation of collagen in the skin and internal organs. Currently, the modified Rodnan Skin Score (mRSS) is the gold standard for evaluating the dermal thickening due to SSc. However, mRSS has noticeable inter‐ and intra‐observer variabilities as quantified by the interclass correlation coefficient (ICC: 0.6‐0.75). In this work, optical coherence elastography (OCE) combined with structural optical coherence tomography (OCT) image analysis was used to assess skin thickness in 12 SSc patients and healthy volunteers. Inter‐ (ICC: 0.62‐0.99) and intra‐observer (ICC > 0.90) assessment of OCT/OCE showed excellent reliability. Clinical assessments, including histologically assessed dermal thickness (DT), mRSS, and site‐specific mRSS (SMRSS) were also performed for further validation. The OCE and OCT results from the forearm demonstrated the highest correlation (OCE: 0.78, OCT: 0.65) with SMRSS. Importantly, OCE and OCT had stronger correlations with the histological DT (OCT: r = .78 and OCE: r = .74) than SMRSS (r = .57), indicating the OCT/OCE could outperform semi‐quantitative clinical assessments such as SMRSS. Overall, these results demonstrate that OCT/OCE could be useful for rapid, noninvasive and objective assessments of SSc onset and monitoring skin disease progression and treatment response.     

Drier tropical forests are susceptible to functional changes in response to a long‐term drought

Climatic changes have profound effects on the distribution of biodiversity, but untangling the links between climatic change and ecosystem functioning is challenging, particularly in high diversity systems such as tropical forests. Tropical forests may also show different responses to a changing climate, with baseline climatic conditions potentially inducing differences in the strength and timing of responses to droughts. Trait‐based approaches provide an opportunity to link functional composition, ecosystem function and environmental changes. We demonstrate the power of such approaches by presenting a novel analysis of long‐term responses of different tropical forest to climatic changes along a rainfall gradient. We explore how key ecosystem's biogeochemical properties have shifted over time as a consequence of multi‐decadal drying. Notably, we find that drier tropical forests have increased their deciduous species abundance and generally changed more functionally than forests growing in wetter conditions, suggesting an enhanced ability to adapt ecologically to a drying environment.     

Effects of Cardiac Myosin Binding Protein-C on Actin Motility Are Explained with a Drag-Activation-Competition Model

Although mutations in cardiac myosin binding protein-C (cMyBP-C) cause heart disease, its role in muscle contraction is not well understood. A mechanism remains elusive partly because the protein can have multiple effects, such as dual biphasic activation and inhibition observed in actin motility assays. Here we develop a mathematical model for the interaction of cMyBP-C with the contractile proteins actin and myosin and the regulatory protein tropomyosin. We use this model to show that a drag-activation-competition mechanism accurately describes actin motility measurements, while models lacking either drag or competition do not. These results suggest that complex effects can arise simply from cMyBP-C binding to actin.     

Material affects attack rates on dummy caterpillars in tropical forest where arthropod predators dominate: an experiment using clay and dough dummies with green colourants on various plant species

Predation can be one of the key factors that determine abundance in insect herbivore communities, and drive evolution of body size, and anti‐predator traits, including crypsis. Population dynamics and selection pressures will depend on the identity of dominant predators in the system, and these may vary substantially among habitats. Arthropods emerge as chief predators on caterpillars in the understorey of non‐montane tropical forest, whereas birds dominate elsewhere. In a tropical forest in Uganda, Africa, we evaluated marks on dummy caterpillars that differed in size, material (clay vs. dough), colourant, and plant species on which dummy caterpillars were exposed. We included live caterpillars to estimate the extent to which studies using artificial caterpillars reflect actual levels of predation. Ants and wasps were the most important damagers of dummy caterpillars, whereas bug and beetle damage was very rare, and no bird or small mammal damage was observed. Daily attack rates did not differ significantly from apparent mortality of live caterpillars (daily mortality = 12.1%), but dummy caterpillars made from dough were attacked more frequently (daily attack rate = 18.4%) than those from clay (daily attack rate = 6.9%). Caterpillars of different colour and size, and caterpillars exposed on different plant species had the same chances to be predated. This is in contrast to results from temperate area studies where birds dominate and are not affected by dummy caterpillar material, but prefer larger caterpillars. Our results are consistent with dominant predators on tropical forest caterpillars being invertebrates that are more chemically than visually oriented, so that: (1) material used for dummy caterpillars is important, (2) background matching is relatively unimportant, and (3) being large may have less of a cost. These patterns in predation might facilitate polyphagy and evolution of large body size in tropical Lepidoptera.