Landscape biogeography and population structuring of a facultatively amphidromous galaxiid fish, Galaxias brevipinnis

Processes responsible for population structuring across spatial and temporal scales represent key components in understanding speciation and evolution. We use a hierarchical approach to investigate the degree and mechanisms of structuring in landlocked and diadromous populations of the facultatively amphidromous fish Galaxias brevipinnis across various temporal and spatial scales in southern New Zealand. To determine long-term structuring, multiple lakes and coastal sites were compared genetically. Short-term structuring was assessed using otolith microchemistry for a subset of sites, and behavioural mechanisms driving population structuring were assessed via larval distributions. Genetic data show that lakes foster divergence of lake-developing populations from each other and from coastal stream populations, whereas there is relatively little structuring within coast or lake populations. However, otolith analyses indicate that on a shorter time scale, most larvae do not disperse, i.e. recruitment is local. Thus, lake and coastal populations show a distinct meta-population structure based on catchment, in contrast to the prevailing assumption of widespread dispersal, with implications for management. Most larvae were distributed in river plumes, suggesting that a simple larval behavioural mechanism, e.g. positive rheotaxis, may result in larval retention within catchments and lakes. However, not all larvae were retained in plumes, creating opportunities for genetic exchange within-lake or among coastal sites. Genetic divergence of lake populations as a consequence of landscape and behaviour provides an insight into the potential of G. brevipinnis to diversify and speciate, when landscape and circumstances align, and also has implications for the management of this and other facultatively amphidromous species.

The concomitant effects of self-limiting insect releases and behavioural interference on patterns of coexistence and exclusion of competing mosquitoes

Aedes aegypti is the dominant vector of dengue, a potentially fatal virus whose incidence has increased eightfold in the last two decades. As dengue has no widely available vaccine, vector control is key to reducing the global public health burden. A promising method is the release of self-limiting Ae. aegypti , which mate with wild Ae. aegypti and produce non-viable offspring. The resultant decrease in Ae. aegypti population size may impact coexistence with Ae. albopictus , another vector of dengue. A behavioural mechanism influencing coexistence between these species is reproductive interference, where incomplete species recognition results in heterospecifics engaging in mating activities. We develop a theoretical framework to investigate the interaction between self-limiting Ae. aegypti releases and reproductive interference between Ae. aegypti and Ae. albopictus on patterns of coexistence. In the absence of self-limiting Ae. aegypti release, coexistence can occur when the strength of reproductive interference experienced by both species is low. Results show that substantial overflooding with self-limiting Ae. aegypti prevents coexistence. For lower release ratios, as the release ratio increases, coexistence can occur when the strength of reproductive interference is increasingly high for Ae. albopictus and increasingly low for Ae. aegypti . This emphasizes the importance of including behavioural ecological processes into population models to evaluate the efficacy of vector control.

Emotional eating and obesity in adults: the role of depression, sleep and genes

Stress and other negative emotions, such as depression and anxiety, can lead to both decreased and increased food intake. The term ‘emotional eating’ has been widely used to refer to the latter response: a tendency to eat in response to negative emotions with the chosen foods being primarily energy-dense and palatable ones. Emotional eating can be caused by various mechanisms, such as using eating to cope with negative emotions or confusing internal states of hunger and satiety with physiological changes related to emotions. An increasing number of prospective studies have shown that emotional eating predicts subsequent weight gain in adults. This review discusses particularly three lines of research on emotional eating and obesity in adults. First, studies implying that emotional eating may be one behavioural mechanism linking depression and development of obesity. Secondly, studies highlighting the relevance of night sleep duration by showing that adults with a combination of shorter sleep and higher emotional eating may be especially vulnerable to weight gain. Thirdly, an emerging literature suggesting that genes may influence body weight partly through emotional eating and other eating behaviour dimensions. The review concludes by discussing what kind of implications these three avenues of research offer for obesity prevention and treatment interventions.

Behavioural Mechanism to Overcome Leadership Challenges: The Role of Inward Looking Leadership

We face leadership challenges arising from conflicting situations and instincts. This paper discusses some of the common modern leadership traits and what our relics suggest. The analysis of most of the leadership theories and practices indicate that finally it is the self-discipline and self-control that can be a major success factor in managing situations, in being more effective leader. Our ancient texts also refer to rising above material growth to attain achievement of maximum joy and fulfilment of life’s objectives. The research shows inward looking approach can help in seeking the true treasures of good judgement and real wisdom within ourselves. Successful leadership requires stepping aside and then to take a look from outside to inside. There is acceptability and concurrence by modern psychologists and thinkers; the approach suggested by our Rishis, Sufis and Zen masters also conveys the same.

Temperature regulation

For many organisms there is a fitness advantage to being warm. Many organisms use behavioural thermoregulation to maintain a high body temperature during the day, basking in the sun to warm up and retreating to the shade to avoid overheating. This option is not open to most aquatic organisms, or those living in soil or sediment. It is also generally not possible for small or nocturnal organisms. A small number of active predatory fish utilise a counter-current heat exchanger (rete mirabile) to retain metabolic heat and warm their muscles, brain or eyes. A few have modified optical muscles as heater organs, and a range of plants generate heat to aid dispersal of scent and attract pollinators. A wide range of larger insects use rapid but unsynchronised muscle contraction to elevate their body temperature prior to flight, or other activity. In hot climates organisms may need to dissipate heat to avoid overheating. The major behavioural mechanism is shade-seeking, or for small organisms stilting or climbing onto objects such as plants to move out of the hottest air net to the ground. Larger mammals may tolerate a limited degree of warming during the day, releasing this in the cool of the night. Evaporative cooling is very effective at losing heat, but because it loses valuable water it can only be used sparingly in arid areas.