Summary: Magnetic orientation responses in animals are often weak and difficult to elicit experimentally. A possible explanation is that the magnetic compass is ‘noisy’ and cannot acquire precise magnetic information over short time periods.
Irreversible sterility of workers and high-volume egg production by queens in the stingless bee Tetragonula carbonaria
Summary: The first experimental evidence of absolute worker sterility in a social insect species. Australian stingless bee workers under a manipulated social environment and diet are irreversibly sterile.
No water, no problem: stage-specific metabolic responses to dehydration stress in annual killifish embryos
Highlighted Article: Annual killifish embryos survive over a year without water. Dormant and actively developing embryos exhibit opposite metabolic responses to dehydration. These responses may contribute to phenotypic variation associated with developmental bet hedging.
Discrimination of small sugar concentration differences helps the nectar-feeding bat Leptonycteris yerbabuenae cover energetic demands
Highlighted Article: Nectar-feeding bats have very high daily energy demands. The bat Leptonycteris yerbabuenae discriminates very small sugar concentration differences, which helps it to avoid physiological constraints.
Extreme diving in mammals: first estimates of behavioural aerobic dive limits in Cuvier's beaked whales
Highlighted Article: Long dives in Cuvier's beaked whales are not followed by prolonged recovery periods, suggesting that diving metabolism is reduced and/or undescribed mechanisms are used to process products of anaerobic metabolism.
METHODS & TECHNIQUES
Summary: A new method for plotting joint poses, inspired by a 16th century map projection, allows coordinate-system-independent measurements of joint mobility and enables accurate comparative studies of joint function.
Differential effects of early growth conditions on colour-producing nanostructures revealed through small angle X-ray scattering and electron microscopy
Summary: A two-stage brood size manipulation experiment in Cyanistes caeruleus, with application of small-angle X-ray scattering and electron microscopy, revealed that structurally coloured feathers are more sensitive to conditions during feather growth than during the first days after hatching.
Summary: Several morphological modifications are likely to contribute to the stiffness of the novel walking appendages in the sea-robin and therefore their ability to facilitate underwater locomotion.
Traction force measurements on male Strepsiptera (Insecta) revealed higher forces on smooth compared with hairy substrates
Summary: Males of the strepsipteran Stylops ovinae develop significantly higher forces on smooth than hairy surfaces; these forces are generated by adhesion and not by mechanical interlocking with host hairs.
A mutation in monoamine oxidase (MAO) affects the evolution of stress behavior in the blind cavefish Astyanax mexicanus
Summary: A mutation in the serotonin neurotransmitter pathway that lowers basal stress levels but increases the amplitude of stress response can spread in cavefish populations living in singular environments.
Measuring power input, power output and energy conversion efficiency in un-instrumented flying birds
Summary: Presentation and evaluation of 13C-labelled sodium bicarbonate (NaBi) combined with particle image velocimetry (PIV) for estimation of flight energetics in birds over a wide range of speeds.
Thermal adaptation in the honeybee (Apis mellifera) via changes to the structure of malate dehydrogenase
Highlighted Article: The cytosolic malate dehydrogenase enzyme of the honeybee has three allozymes that show parallel temperature clines on four continents, reflecting the adaptive advantage/disadvantage of each allele at different temperatures.
Drinking made easier: honey bee tongues dip faster into warmer and/or less viscous artificial nectar
Summary: Fluidic modelling and theoretical analysis of the honey bee feeding mechanism reveals an adaptation strategy in which bees respond to variation in nectar properties by regulating dipping frequency.
Respirometry and cutaneous oxygen flux measurements reveal a negligible aerobic cost of ion regulation in larval zebrafish (Danio rerio)
Summary: The energetic cost of epithelial ion transport in larval zebrafish is estimated to be low based on relatively constant in vivo O2 flux across cutaneous ionocytes, despite widely varying rates of Na+ uptake.
Variation in the response to exercise stimulation in Drosophila: marathon runner versus sprinter genotypes
Summary: Drosophila strains differ in their response to exercise stimulation, which is controlled at least in part by genetic variation and sex.
Unequal rewarding of three metabolizable sugars – sucrose, fructose and glucose – in olfactory learning and memory in Bactrocera dorsalis
Summary: Bactrocera dorsalis can learn to discriminate three sugars – sucrose, fructose and glucose – through both pre- and post-ingestive signals, which might be a strategy for flies to assess the quality of the food.
Summary: A species contrast in patterns of noradrenaline levels reveals that different brain areas are responsible for the encoding of social signals versus preferences for those signals.
Estimation of the force–velocity properties of individual muscles from measurement of the combined plantarflexor properties
Summary: Incorporating appropriate fiber properties and muscle architecture is necessary to evaluate the contribution of individual muscles to combined plantarflexor force-velocity properties.
Editor's choice: Channel catfish use their dorsal body muscles to stabilize the head during suction feeding, while the ventral body muscles power mouth expansion.
Cortisol is an osmoregulatory and glucose-regulating hormone in Atlantic sturgeon, a basal ray-finned fish
Summary: Cortisol increases during exposure to seawater and exogenous cortisol upregulates gill NKA, NKCC and H+-ATPase and plasma glucose in sturgeon; thus, cortisol is a key osmoregulatory and glucocorticoid hormone in chondrosteans.