Kramerjansen5802

Anthropogenic noise sources range from intermittent to continuous, with seismic and navy sonar technology moving towards near-continuous transmissions. Continuous active sonar (CAS) may be used at a lower amplitude than traditional pulsed active sonar (PAS), but potentially with greater cumulative sound energy. We conducted at-sea experiments to contrast the effects of navy PAS vs. CAS on sperm whale behaviour using animal-attached sound and movement-recording tags (n=16 individuals) in Norway. Changes in foraging effort and proxies for foraging success and cost during sonar and control exposures were assessed while accounting for baseline variation (individual effects, time of day, bathymetry and blackfish [pilot/killer whale] presence) in generalized additive mixed models. We found no reduction in time spent foraging during exposures to medium-level PAS (MPAS) transmitted at the same peak amplitude as CAS. In contrast, we found similar reductions in foraging during CAS (df=1, F=8.0, p=0.005) and higher amplitude PAS (df=1, F=20.8, p less then 0.001) when received at similar energy levels integrated over signal duration. These results provide clear support for sound energy over amplitude as the response driver. We discuss the importance of exposure context and need to measure cumulative sound energy to account for intermittent vs. more continuous sources in noise impact assessments. © 2020. Published by The Company of Biologists Ltd.Organisms with wide environmentally-induced morphological plasticity and cosmopolitan distribution, e.g., the common freshwater rotifer Keratella cochlearis, are ideal models to study the evolution of plastic polymorphisms and the capacity of zooplankton to adapt to local selection conditions. We investigated population-level differences (population-by-environment interaction) in sensitivity to food availability and temperature-induced phenotypic plasticity between two clones of K. cochlearis (Gosse) isolated from neighboring populations in Ruidera Natural Park (Spain) with different trophic statuses Tinaja (TIN) lake (mesotrophic) and Cueva Morenilla (MOR) lake (eutrophic). Using common-garden experiments, each clone proved to have a different sensitivity to food availability, with substantial phenotypic differences between them. When rotifers grew at moderate temperature (15.6°C), low food levels were more efficiently used by the TIN versus MOR clone, whereas high food levels were more efficiently used by the MOR versus TIN clone. The posterior spine was much longer and the lorica wider in the TIN versus MOR clone, with no difference in lorica length. Phylogenetic analysis based on COI sequences showed that both populations have the same haplotype. This is the first study to show possible local adaptation by a rotifer species to habitats that consistently differ in food availability. We also detected an intriguing deviation from the expected negative relationship between posterior spine length and temperature. Our experimental results indicate that intermediate temperatures may activate the gene responsible for spine elongation in K. cochlearis This suggests that rotifers in nature could use water temperature as proxy signal of a change in predation risk before defense is needed. © 2020. Published by The Company of Biologists Ltd.Immune systems provide a key defence against diseases. However, they are not a panacea and so both vertebrates and invertebrates co-opt naturally occurring bioactive compounds to treat themselves against parasites and pathogens. In vertebrates this co-option is complex, with pharmacodynamics leading to differential effects of treatment at different life stages, which may reflect age-linked differences in the immune system. However, our understanding of pharmacodynamics in invertebrates is almost non-existent. Critically, this knowledge may elucidate broad parallels across animals in regard to the requirement for the co-option of bioactive compounds to ameliorate disease. Here we use biochanin A, an isoflavone found in the pollen of red clover (Trifolium pratense), to therapeutically treat Nosema bombi (Microsporidia) infection in bumblebee (Bombus terrestris) larvae and adults, and thus examine age-linked pharmacodynamics in an invertebrate. Therapeutic treatment of larvae with biochanin A did not reduce the infection intensity of N. bombi in adults. In contrast, therapeutic treatment of adults did reduce the infection intensity of N. bombi This transition in parasite resistance to bioactive compounds mirrors the age-linked pharmacodynamics of vertebrates. Ivacaftor mw Understanding how different life-history stages respond to therapeutic compounds will provide novel insights into the evolution of foraging and self-medication behaviour in natural systems more broadly. © 2020. Published by The Company of Biologists Ltd.The fat body, a major metabolic hub in insects, is involved in many functions, e.g., energy storage, nutrient sensing, and immune response. In social insects, fat appears to play an additional role in division of labour between egg-layers and workers, which specialize in non-reproductive tasks inside and outside their nest. For instance, reproductives are more resistant to starvation, and changes in fat content have been associated with the transition from inside to outside work or reproductive activities. However, most studies remained correlative and we still need to unravel the causal interrelations between fat content, and division of both reproductive and non-reproductive labour. Clonal ants, e.g., Platythyrea punctata, are ideal models for studying task partitioning without confounding variation in genotype and morphology. In this study, we examined the range of variation and flexibility of fat content throughout the lifespan of workers, the thresholds of corpulence associated with foraging or reproduction and whether low fat content is a cause rather than a consequence of the transition to foraging. We found that lipid stores change with division of labour from corpulent to lean and, in reverted nurses, back to corpulent. In addition, our data show the presence of fat content thresholds that trigger the onset of foraging or egg laying behaviour. Our study supports the view that mechanisms that regulate reproduction and foraging in solitary insects, in particular the nutritional status of individuals, have been co-opted to regulate division of labour in colonies of social insects. © 2020. Published by The Company of Biologists Ltd.