The coevolution of long‐term pair bonds and cooperation

The evolution of social traits may not only depend on but also change the social structure of the population. In particular, the evolution of pairwise cooperation, such as biparental care, depends on the pair‐matching distribution of the population, and the latter often emerges as a collective outcome of individual pair‐bonding traits, which are also under selection. Here, we develop an analytical model and individual‐based simulations to study the coevolution of long‐term pair bonds and cooperation in parental care, where partners play a Snowdrift game in each breeding season. We illustrate that long‐term pair bonds may coevolve with cooperation when bonding cost is below a threshold. As long‐term pair bonds lead to assortative interactions through pair‐matching dynamics, they may promote the prevalence of cooperation. In addition to the pay‐off matrix of a single game, the evolutionarily stable equilibrium also depends on bonding cost and accidental divorce rate, and it is determined by a form of balancing selection because the benefit from pair‐bond maintenance diminishes as the frequency of cooperators increases. Our findings highlight the importance of ecological factors affecting social bonding cost and stability in understanding the coevolution of social behaviour and social structures, which may lead to the diversity of biological social systems.     

The Radical SAM Superfamily

ABSTRACT

The radical S-adenosylmethionine (SAM) superfamily currently comprises more than 2800 proteins with the amino acid sequence motif CxxxCxxC unaccompanied by a fourth conserved cysteine. The charcteristic three-cysteine motif nucleates a [4Fe–4S] cluster, which binds SAM as a ligand to the unique Fe not ligated to a cysteine residue. The members participate in more than 40 distinct biochemical transformations, and most members have not been biochemically characterized. A handful of the members of this superfamily have been purified and at least partially characterized. Significant mechanistic and structural information is available for lysine 2,3-aminomutase, pyruvate formate-lyase, coproporphyrinogen III oxidase, and MoaA required for molybdopterin biosynthesis. Biochemical information is available for spore photoproduct lyase, anaerobic ribonucleotide reductase activation subunit, lipoyl synthase, and MiaB involved in methylthiolation of isopentenyladenine-37 in tRNA. The radical SAM enzymes biochemically characterized to date have in common the cleavage of the [4Fe–4S]^{1 +} –SAM complex to [4Fe–4S]^{2 +}–Met and the 5′ -deoxyadenosyl radical, which abstracts a hydrogen atom from the substrate to initiate a radical mechanism.     

The Relationship between Personality Match and Pet Satisfaction among Dog Owners

ABSTRACT

We investigated the extent to which personality match between dog and owner is related to pet satisfaction. Prior research shows that owners relinquish dogs at a high rate, not only in the United States, but also in other countries. New procedures to match owners to future pets could reduce the problem of homeless pets. These were developed after examining the literature to determine all possible traits in dogs and conducting structured interviews to check for further traits. After doing this, 45 traits were determined, and two surveys were created. One survey assessed the personality traits of the dog, and the other assessed the owner's personality traits. In our study, 88 dog owners were asked to report their satisfaction with their self-selected dog and to describe their dog's personality characteristics, based on eight dimensions. Correlations between dog satisfaction scores and dog–owner personality match revealed four characteristics that were significantly associated with satisfaction: tendency to share possessions, love of running outside, likeliness of being destructive, and ability to get along with others. These results suggest that prospective dog owners may want to consider adopting dogs who match their personality on these characteristics. Matching the personality of dogs and their owners on a few characteristics may predict owner satisfaction. This is important as it may reduce the number of dogs that are relinquished by owners as well as the number of dogs left homeless each year.     

计算机视觉在线虫进食行为自动分析中的应用

秀丽隐杆线虫被广泛地用作研究基因与行为关系的绝佳模式生物.线虫的咽部神经元回路控制着复杂的进食行为.为了研究进食行为的分子机制,有必要对线虫进食行为表型分析鉴定.然而,目前为止,几乎所有的线虫进食行为表型鉴定都是通过人眼来判断.因为其泵入食物的肌肉运动频率高,该行为的分析是很困难而且效率低下的.为解决这个问题,我们设计了基于计算机视觉技术的自动化成像系统来高通量分析线虫进食行为表型.此成像系统对进食表型的检测准确率达到98%以上,并使得连续可靠地分析其表型细微变化成为可能.同时,在保证高准确率的前提下单位时间内分析数据的效率比人工分析提高了3倍.     

The magnitude of local adaptation under genotype‐dependent dispersal

Dispersal moves individuals from patches where their immediate ancestors were successful to sites where their genotypes are untested. As a result, dispersal generally reduces fitness, a phenomenon known as “migration load.” The strength of migration load depends on the pattern of dispersal and can be dramatically lessened or reversed when individuals move preferentially toward patches conferring higher fitness. Evolutionary ecologists have long modeled nonrandom dispersal, focusing primarily on its effects on population density over space, the maintenance of genetic variation, and reproductive isolation. Here, we build upon previous work by calculating how the extent of local adaptation and the migration load are affected when individuals differ in their dispersal rate in a genotype‐dependent manner that alters their match to their environment. Examining a one‐locus, two‐patch model, we show that local adaptation occurs through a combination of natural selection and adaptive dispersal. For a substantial portion of parameter space, adaptive dispersal can be the predominant force generating local adaptation. Furthermore, genetic load may be largely averted with adaptive dispersal whenever individuals move before selective deaths occur. Thus, to understand the mechanisms driving local adaptation, biologists must account for the extent and nature of nonrandom, genotype‐dependent dispersal, and the potential for adaptation via spatial sorting of genotypes.     

Nest covering in plovers: How modifying the visual environment influences egg camouflage

Camouflage is one of the most widespread antipredator defences, and its mechanistic basis has attracted considerable interest in recent years. The effectiveness of camouflage depends on the interaction between an animal's appearance and its background. Concealment can therefore be improved by changes to an animal's own appearance, by behaviorally selecting an optimal background, or by modifying the background to better match the animal's own appearance. Research to date has largely focussed on the first of these mechanisms, whereas there has been little work on the second and almost none on the third. Even though a number of animal species may potentially modify their environment to improve individual‐specific camouflage, this has rarely if ever been quantitatively investigated, or its adaptive value tested. Kittlitz's plovers (Charadrius pecuarius) use material (stones and vegetation) to cover their nests when predators approach, providing concealment that is independent of the inflexible appearance of the adult or eggs, and that can be adjusted to suit the local surrounding background. We used digital imaging and predator vision modeling to investigate the camouflage properties of covered nests, and whether their camouflage affected their survival. The plovers' nest‐covering materials were consistent with a trade‐off between selecting materials that matched the color of the eggs, while resulting in poorer nest pattern and contrast matching to the nest surroundings. Alternatively, the systematic use of materials with high‐contrast and small‐pattern grain sizes could reflect a deliberate disruptive coloration strategy, whereby high‐contrast material breaks up the telltale outline of the clutch. No camouflage variables predicted nest survival. Our study highlights the potential for camouflage to be enhanced by background modification. This provides a flexible system for modifying an animal's conspicuousness, to which the main limitation may be the available materials rather than the animal's appearance.