Summary: Stamatakis & Stuber (2012)

Negative reward-related information is carried to the ventral portion of the middle brain (including the rostromedial tegmental nucleus) via projections of the lateral habenula. Stamatakis & Stuber (2012) studied the behavioural complications of selective activation of this particular pathway in the brain in mice. They found that aversive stimuli increased the excitatory drive of the lateral habenula, which resulted in conditioned, passive and active behavioural avoidance of the aversive stimulus. The activity of these projections to the midbrain is thus aversive, and functions to negatively reinforce behavioural response.

Summary: Markham et al. (2012)

Social species benefit from group living, however, social groups must also compete for resources with other groups. Competition can be a major driver influencing a group's movements and space use and has the potential to shape the evolution of sociality. Markham et al. (2012) investigated the ecological factors influencing baboon Papio cynocephalus group dominance, with a specific focus on what spatial features influence dominance and what occurs when a group is defeated. They found that the number of adult males in a group predicted which group would win a direct conflict, but they also found that a group's intensity of use of areas associated with the encounter location also predicted a win, over a longer time period (9-12 months). Losing groups  used the area surrounding the encounter location less, possibly incurring short-term costs associated with reduced access to resources. Markham et al.'s (2012) study highlights the importance of inter-group competition on social group space use.

Summary: Kronfeld-Schor et al. (2013)

The circadian "clock" is the body's internal mechanism for keeping track of time. This "clock" is driven by an individual's physiology and it influences an animal's behaviour on a daily basis. Alterations to environmental light conditions results in the natural time-keeping rhythms to become entrained to particular light-dark (day-night) cycles. The circadian system consists of molecular, cellular, tissue and organismal levels, and how these levels contribute to an individuals behaviour is quite well understood. The shortcomings of these studies relate to the species studied, typically those that are standard laboratory species that have been maintained in captivity (so called "model" organisms). Kronfeld-Schor et al. (2013) suggest that to understand the evolutionary significance of the circadian clock, we need to study a variety of species from multiple taxonomic groups that display a diversity in activity patterns (e.g. diurnal, nocturnal, cathemeral, crepuscular). In a special feature of the Proceedings of the Royal Society of London B, Kronfeld-Schor et al. (2013) highlight seven papers that attempt to explore the adaptive significance of the circadian clock, with the reviews including the influence of moonlight, latitude, evolutionary history, sociality, temporal niche specialization, annual variation and post-transcriptional mechanisms. These seven papers demonstrate the complexity, as well as the diversity, of the circadian system.

Summary: Madden & Whiteside (2013)

Females of many species show individual differences in their choice of mate, which has subsequent effects on fitness. These choices are shaped by early life experiences. Madden & Whiteside (2013) studies how adult sexual behaviour of pheasants Phasianus colchicus is influenced by the sex ratio of the clutch at rearing. When females are raised in equal sex ratio clutches, they showed a strong discrimination between males of different attractiveness, while females raised in female-biased clutches did not discriminate between males. These females also showed highly skewed mating success, with most achieving no copulations and relatively few gaining the most. Madden & Whiteside (2013) suggest that the early life environment could influence variation in female mate choice, which could ultimately maintain male trait variation that is otherwise under strong direction selection.

Summary: McNamara et al. (2013)

Animals are able to evaluate the word in relative terms through successive contrast effects. These behaviours are dependent on the state of the current conditions (better or worse) in relation to previous conditions. Generally, descriptive models of various processes (psychological and physiological) attempt to explain these effects. The factors promoting the evolution of these contrast effects has been relatively poorly studied. McNamara et al. (2013) used simple and general optimality models to show that adaptive responses to uncertainty result in contrast effects in an environment that is dynamic and unpredictable. They suggest that sensitivity to past conditions will be selected for by a wide range of environmental change patterns, which can generate either positive or negative contrast effects. Based on these findings, McNamara et al. (2013) they suggest that environmental stochasticity and uncertainty should be included into future adaptive behaviour models.

Summary: Allen et al. (2013)

Neornithes (living birds) locomote by feather-aided flight and they have a bipdeal crouched hindlimb support structure that facilitates walking / running. The evolution of both these traits is controversial, however, computer modelling and well preserved specimens are paving the way for identifying the underlying biomechanics of locomotion. Allen et al. (2013) digitally reconstructed the body morphology of species across the Archosauria clade (17 species), using three-dimensional reconstruction of body shape, to measure the trends in evolutionary locomotor biomechanics. Species used included the four major species representing major key stages in avian body plan evolution: Microraptor, Archaeopteryx, Pengornis and Yixianornis. Allen et al. (2013) suggest that a more-crouched limb posture was acquired gradually in a step-wise fashion through theropod evolution, although this was accelerated in the Maniraptoran clade. They also found that enlargement of the pectoral limb, with other associated trends, had a stronger influence on the evolution of hindlimb posture than tail reduction. Within the Manirapotra, Allen et al. (2013) also found that the evolution of flight is closely correlated with the accelerated morpho-functional trends observed. They suggest that anatomical novelties in the pelvic and pectoral limbs is closely linked to the evolution of flight in birds.

Summary: Liu et al. (2012)

Prolonged social isolation results in stress, particularly in group-living species. Isolation stress, particularly during the early developmental period, may then have a profound influence on cognitive and endocrine function, as well as behaviour. Liu et al. (2012) found that prolonged social isolation also influenced transcriptional and structural alterations to neurons in the prefontal cortex. They also found that re-integration with the social group normalized transciptional and behavioural changes. In addition, they noted that shorter periods of isolation did not induce behavioural change, but did influence structure of chromatin and myelin. Liu et al. (2012) suggest that the alteration of myelination in response to social interactions could be a form of phenotypic plasticity in adults.