Summary: This Review discusses the energetic cost of colour change and highlights the effects of this cost on animals that change colour rapidly and slowly and how it can be avoided or lessened.
Summary: Amazonia is now in crisis owing to climate change and other anthropogenic pressures. High temperature is the most critical of the physiological threats to its unique and diverse fish fauna.
Summary: Residual force enhancement (rFE) is thought to be achieved by stretching an active muscle at any speed. However, experiments indicate that fast stretching eliminates rFE, presumably by preventing strong cross-bridge binding.
METHODS & TECHNIQUES
An accelerometer-derived ballistocardiogram method for detecting heart rate in free-ranging marine mammals
Highlighted Article: Validation of a computational method for extracting heart rate in free-ranging cetaceans from high-resolution accelerometer data using a ballistocardiogram.
Summary: After 7 months with weekly bouts of mechanical stress, California mussels had repaired shell damage and maintained shell strength; repair was associated with morphological changes but came at a significant cost.
Seasonal changes in membrane structure and excitability in retinal neurons of goldfish (Carassius auratus) under constant environmental conditions
Summary: Neurons isolated from the retina of goldfish held under constant environmental conditions undergo seasonal changes in membrane structure and excitability.
Summary: Residual force enhancement is reduced in fiber bundles from mdm mice, supporting a role for titin in residual force enhancement.
Experimental warming during incubation improves cold tolerance of blue tit (Cyanistes caeruleus) chicks
Summary: Chicks from experimentally heated nests demonstrate greater cold tolerance compared with control chicks when exposed to a series of post-hatch cooling challenges.
Summary: Site-directed mutagenesis indicates that spectral tuning in retinochrome is not solely additive but is instead influenced by intra-molecular epistasis.
Summary: Bimodal enhancement during learning and memory tasks in africanized honey bees increases as the stimulus intensity of its unimodal components decreases; this indicates that learning performance depends on the interaction between the intensity of its components and the nature of the sensory modalities involved, supporting the principle of inverse effectiveness.
Summary: Cockroaches make adjustments to better roll into gaps to traverse cluttered large obstacles.
Locomotion in the pseudoscorpion Chelifer cancroides: forward, backward and upside-down walking in an eight-legged arthropod
Highlighted Article: Pseudoscorpions perform an alternating tetrapod gait during forward and backward locomotion, with consistently higher speeds during backward motion, while no fixed leg coupling occurs during upside-down walking.
The functional basis for variable antipredatory behavioral strategies in the chameleon Chamaeleo calyptratus
Summary: Behavioral antipredator response in chameleons is predicted by both the functional capacity to perform these behaviors and the immediate environmental context for that individual.
Highlighted Article: Air-breathing mechanics in Xenopus laevis tadpoles change over development as they transition from bubble-sucking to breaching. Differences in breathing mechanics appear to be primarily a consequence of growth, and despite temporal correlations to changes in respiratory physiology, are not linked to changes in lung morphology.
The acute effects of higher versus lower load duration and intensity on morphological and mechanical properties of the healthy Achilles tendon: a randomized crossover trial
Summary: High levels of load duration and intensity have the greatest acute effect on the free Achilles tendon volume and stiffness.
Anna's hummingbird (Calypte anna) physiological response to novel thermal and hypoxic conditions at high elevations
Highlighted Article: Hummingbirds show increased torpor use in response to colder thermal conditions above their elevational range limit but exhibit a decrease in hovering performance in response to lower oxygen conditions.