Issues

Summary: We review the metabolic, morphological and physiological features unique to embryonic and larval fishes that are necessary to cope with an amino acid-fuelled metabolism and lack of a functional gill.

Summary: Recent work has adapted methods for assessing emotions in humans and other animals, to invertebrates, with intriguing results. This Review interprets and discusses their utility with respect to the evolution and neurobiology of emotion.

Summary: Exposure to constant light or constant darkness accelerates the onset of spring physiology in overwintering reindeer; this has implications for current models of circannual time-keeping in mammals.

Summary: Turtle humeri experience reduced torsional loads during swimming compared with terrestrial walking. Such reductions may have facilitated the transition from tubular to flattened limb bones in secondarily aquatic tetrapods.

Summary: A new statistical package developed in R for the maximum likelihood analysis of animal orientation data. Both simulated and empirical examples are provided for demonstration.

Highlighted Article: Anoxia-tolerant crucian carp sustain brain cell death during early re-oxygenation, as well as impaired memory, although damage is transient and does not diminish learning ability.

Summary: Functional trade-offs of the hyobranchial apparatus result in lower tongue-projection distance, velocity, acceleration and power in semi-aquatic and aquatic salamandrids compared with terrestrial specialists.

Summary: Damselfly larvae benefit from a heat wave by increasing growth rate and immune components, which can be attributed to an increase in food intake.

Highlighted Article: Hyperbaric limitation of depth range suggests the incorporation of hydrostatic pressure into a complex model of environmental tolerance, where energy limitation constrains biogeographic range, and into the metabolic framework for ecology and evolution.

Summary: Male mosquitoes possess at least eight groups of auditory neurons distinct in frequency tuning. They gradually amplify receptor potentials in a non-spiking mode. Individual frequencies range from 85 to 470 Hz.

Summary: Haemoglobin–O₂ binding properties of African mole rats reveal low specific CO₂ sensitivities compared with humans that predictably safeguard O₂ uptake and transport under hypoxic and hypercapnic conditions.

Summary: Placement of unrelated tadpoles on adult poison frogs triggers a cascade of parental behaviours involving tadpole transport and spatial memory use in both sexes, despite the asymmetric parental sex roles.

Editors' Choice: Fights between parasitoid females require little energy, but drilling through seeds to access hosts is expensive. Females avoid metabolic costs by reusing holes drilled by rivals (superparasitism).

Summary: The function of dorsal fins varies among shark species, and these fins can act in either a stabilizing or thrust-generating role.

Summary: Elevated temperature (>22°C) reduces growth rate and induces endocrine and cellular stress responses of brook trout. Daily temperature oscillation around a mean temperature of 21°C decreases growth and increases heat shock proteins.

Summary: Alkaline phosphatase activity and immunochemistry reveal that oyster germline cells are located in the gonad duct outer edge during the resting period and proliferate very early during the next sexual cycle.

Summary: Freshwater mayfly nymphs regulate salt and water balance using the alimentary canal, Malpighian tubules and tracheal gills, and data provide the first direct evidence that the tracheal gills are ion transport organs.

Highlighted Article: Investigation of the molecular mechanism of an ancient physiological behaviour in sponges in which engulfed quartz particles are fibrogenic and the process is cytokine mediated as in human fibrosis.

Summary: Genome-wide DNA methylation variation in subspecies of house sparrow is largely independent of subspecies designation and does not follow differences in habitat, but is associated with several other biological phenomena such as morphology, sex and commensalism.

Summary: The large black chafer Holotrichia parallela has an endogenous circa‘bi'dian rhythm, which is seemingly produced by the circadian clock system. The 2-day periodicity appears in both the laboratory and the field.

Summary: Changes in mitochondrial activity and hypoxia gene expression in the head, thorax and abdomen of honey bee workers are associated with the nurse bee to forager transition.

Summary: Hypobranchial muscles of bamboo sharks allow for storage and release of elastic strain energy during suction feeding, which is facilitated by a four-bar linkage that links jaw and hyoid depression.

Summary: Developmental trajectory just prior to fledging in songbirds may be hardwired across natural and experimentally manipulated environmental conditions, but shows oxidative stress cost.

Summary: Dihydrotestosterone mimics the effects of testosterone on growth and coloration in a female-larger lizard, and both sexes share downstream regulatory mechanisms required for growth inhibition and enhanced coloration in response to androgens.