Linking cognition with fitness in a wild primate: fitness correlates of problem-solving performance and spatial learning ability.

Linking the cognitive performance of wild animals with fitness consequences is crucial for understanding evolutionary processes that shape individual variation in cognition. However, the few studies that have examined these links revealed differing relationships between various cognitive performance measures and fitness proxies. To contribute additional comparative data to this body of research, we linked individual performance during repeated problem-solving and spatial learning ability in a maze with body condition and survival in wild grey mouse lemurs (Microcebus murinus). All four variables exhibited substantial inter-individual variation. Solving efficiency in the problem-solving task, but not spatial learning performance, predicted the magnitude of change in body condition after the harsh dry season, indicating that the ability to quickly apply a newly discovered motor technique might also facilitate exploitation of new, natural food resources. Survival was not linked with performance in both tasks, however, suggesting that mouse lemurs' survival might not depend on the cognitive performances addressed here. Our study is the first linking cognition with fitness proxies in a wild primate species, and our discussion highlights the importance and challenges of accounting for a species' life history and ecology in choosing meaningful cognitive and fitness variables for a study in the wild.This article is part of the theme issue 'Causes and consequences of individual differences in cognitive abilities'.

Correlation of Serum Levels of IgE Autoantibodies Against BP180 With Bullous Pemphigoid Disease Activity.

Importance: Bullous pemphigoid (BP) is by far the most frequent autoimmune blistering disease. The presence of IgE autoantibodies against the transmembrane protein BP antigen 2 (BP180, type XVII collagen) has previously been reported in 22% to 100% of BP serum samples, and the pathogenic relevance of anti-BP180 IgE has been suggested in various experimental models and by the successful use of omalizumab in individual patients with BP. Objectives: To determine the rate of anti-BP180-reactive IgE in BP, to evaluate the diagnostic relevance of anti-BP180 IgE in BP, and to correlate anti-BP180 IgE with disease activity and the clinical phenotype of patients with BP. Design, Setting, and Participants: This case-control cohort study examined 3 groups of patients with BP. Sixty-five patients with BP underwent an enzyme-linked immunosorbent assay for IgE antibodies against the 16th noncollagenous domain of BP180 (NC16A); 52 consecutive patients with BP underwent clinical evaluation with the Bullous Pemphigoid Disease Activity Index (BPDAI); and 36 patients with BP without anti-BP180 NC16A IgG reactivity underwent evaluation of the diagnostic importance of serum anti-BP180 IgE. In addition, 49 age-matched control individuals with noninflammatory dermatoses, 127 controls undergoing allergy testing for IgE levels, and 30 controls with pemphigus vulgaris or pemphigus foliaceus were included for comparison. Patients were seen at a university clinic from January 1, 2008, to July 31, 2014. Main Outcomes and Measures: Serum anti-BP180 NC16A IgE and IgG levels and BPDAI scores. Results: Of 117 patients with BP (69 women and 48 men), anti-BP180 NC16A serum IgE was detected in 47 (40.2%) and correlated with disease activity as measured by total BPDAI (r = 0.918; P = .06). An intraindividual correlation of anti-BP180 NC16A serum levels with the total BPDAI was observed during the course of the disease in 10 randomly selected patients with BP (r = 0.983; P = .003). Although no association of circulating BP180 NC16A IgE antibodies with urticarial or erythematous lesions was observed (r = 0.481; P = .31), the presence of IgG anti-BP180 NC16A antibodies was associated with the occurrence of erosions and blisters (r = 0.985; P = .006) but not urticarial and erythematous lesions (r = 0.632; P = .23). Assaying for anti-BP180 IgE increased the diagnostic sensitivity by only 2.2% (1 of 46 serum samples) when combined with the IgG anti-BP180 enzyme-linked immunosorbent assay. Conclusions and Relevance: Although detection of serum anti-BP180 IgE is not of diagnostic importance, it may be relevant for therapeutic decisions (eg, the use of anti-IgE treatment). The correlation of serum anti-BP180 NC16A IgE levels with disease activity in patients with BP supports the notion that anti-BP180 IgE is of pathogenic relevance. Our observation that IgG anti-BP180 antibodies are related to the occurrence of blisters and erosions may encourage further studies on the association of fine autoantibody reactivities with clinical features of BP.

Innovation and behavioral flexibility in wild redfronted lemurs (Eulemur rufifrons).

Innovations and problem-solving abilities can provide animals with important ecological advantages as they allow individuals to deal with novel social and ecological challenges. Innovation is a solution to a novel problem or a novel solution to an old problem, with the latter being especially difficult. Finding a new solution to an old problem requires individuals to inhibit previously applied solutions to invent new strategies and to behave flexibly. We examined the role of experience on cognitive flexibility to innovate and to find new problem-solving solutions with an artificial feeding task in wild redfronted lemurs (Eulemur rufifrons). Four groups of lemurs were tested with feeding boxes, each offering three different techniques to extract food, with only one technique being available at a time. After the subjects learned a technique, this solution was no longer successful and subjects had to invent a new technique. For the first transition between task 1 and 2, subjects had to rely on their experience of the previous technique to solve task 2. For the second transition, subjects had to inhibit the previously learned technique to learn the new task 3. Tasks 1 and 2 were solved by most subjects, whereas task 3 was solved by only a few subjects. In this task, besides behavioral flexibility, especially persistence, i.e., constant trying, was important for individual success during innovation. Thus, wild strepsirrhine primates are able to innovate flexibly, suggesting a general ecological relevance of behavioral flexibility and persistence during innovation and problem solving across all primates.

Manual lateralization in wild redfronted lemurs (Eulemur rufifrons) during spontaneous actions and in an experimental task.

The dominant use of one hand is a striking feature of humans, but manual lateralization can be found in a variety of other species as well. In primates, the lateralization in hand use varies among species and several theories such as the "postural origin," "task complexity," or "development theory" have been suggested to explain this variation. In order to contribute comparative data on this phenomenon from a basal primate, we studied manual lateralization in wild redfronted lemurs (Eulemur rufifrons). Data were collected on four groups at Kirindy Forest, western Madagascar, during spontaneous actions and by confronting them with artificial feeding boxes. The lemurs did not exhibit manual lateralization on a group level in either condition. More individuals showed a hand preference in the experimental task, and the preferences were stronger compared to spontaneous actions. The direction of individual hand preferences was not consistent across the two conditions. The results of this study show that measuring manual laterality in different contexts can yield different results. Manual lateralization in wild redfronted lemurs therefore seems to be flexible and situation dependent and probably not ecologically relevant in their natural habitat.