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Ending hunger and alleviating poverty are key goals for a sustainable future. Food security is a constant challenge for agrarian communities in low-income countries, especially in Madagascar. We investigated agricultural practices, household characteristics, and food security in northeast Madagascar. We tested whether agricultural practices, demographics, and socioeconomics in rural populations were related to food security. Over 70% of respondents reported times during the last three years during which food for the household was insufficient, and the most frequently reported cause was small land size (57%). The probability of food insecurity decreased with increasing vanilla yield, rice yield, and land size. There was an interaction effect between land size and household size; larger families with smaller land holdings had higher food insecurity, while larger families with larger land had lower food insecurity. Other socioeconomic and agricultural variables were not significantly related to food insecurity, including material wealth, education, crop diversity, and livestock ownership. Our results highlight the high levels of food insecurity in these communities and point to interventions that would alleviate food stress. In particular, because current crop and livestock diversity were low, agricultural diversification could improve outputs and mitigate food insecurity. Development of sustainable agricultural intensification, including improving rice and vanilla cultivation to raise yields on small land areas, would likely have positive impacts on food security and alleviating poverty. Increasing market access and off-farm income, as well as improving policies related to land tenure could also play valuable roles in mitigating challenges in food security. [ABSTRACT FROM AUTHOR]

Sleep in the primate order remains understudied, with quantitative estimates of sleep duration available for less than 10% of primate species. Even fewer species have had their sleep synchronously quantified with meteorological data, which have been shown to influence sleep–wake regulatory behaviors. We report the first sleep duration estimates in two captive gibbon species, the Javan gibbon (Hylobates moloch) and the pileated gibbon (Hylobates pileatus) (N = 52 nights). We also investigated how wind speed, humidity, temperature, lunar phase, and illumination from moonlight influence sleep–wake regulation, including sleep duration, sleep fragmentation, and sleep efficiency. Gibbons exhibited strict diurnal behavior with little nighttime activity and mean total average sleep duration of 11 h and 53 min for Hylobates moloch and 12 h and 29 min for Hylobates pileatus. Gibbons had notably high sleep efficiency (i.e., time score asleep divided by the time they spent in their sleeping site, mean of 98.3%). We found illumination from moonlight in relation to lunar phase and amount of wind speed to be the strongest predictors of sleep duration and high-quality sleep, with increased moonlight and increased wind causing more fragmentation and less sleep efficiency. We conclude that arousal threshold is sensitive to nighttime illumination and wind speed. Sensitivity to wind speed may reflect adaptations to counter the risk of falling during arboreal sleep. [ABSTRACT FROM AUTHOR]

With the predicted increase in extreme weather events as a result of global climate change, animals living in dry or seasonally dry habitats are likely to experience dramatic fluctuations in water availability from season to season and year to year. Understanding how animals respond to short-term changes in water availability is paramount for future conservation and management of water-dependent wild populations. We investigated how short-term changes to the availability of water influenced habitat use of four groups of red-fronted lemurs (Eulemur rufifrons) in a dry deciduous forest in western Madagascar using detailed spatial data collected from GPS collars over 15 weeks. We experimentally manipulated water availability in the habitat and compared ranging patterns of the lemurs during the experiments to those before and after the experiments. Lemur groups shifted the intensity of their habitat use relative to changes in natural and experimental water availability. Specifically, lemurs were more likely to spend time in areas near experimental water sources during the experiment than in the same areas without water. Lemurs were less likely to spend time near previous habitual water sources when experimental water sources were available. We observed shifts in ranging intensity in response to natural changes to water availability when waterholes disappeared across the dry season. Our findings support the importance of water for shaping wild animal ranging patterns. We propose that water should be a primary consideration in future studies of habitat use, especially given the potential for climate change and human land use to further alter water availability for wild animals. [ABSTRACT FROM AUTHOR]

Sleep is essential for survival, yet it represents a time of extreme vulnerability, including through exposure to parasites and pathogens transmitted by biting insects. To reduce the risks of exposure to vector-borne disease, the encounter-dilution hypothesis proposes that the formation of groups at sleep sites is influenced by a "selfish herd" behavior, where individuals dilute risk by sleeping with other group members. To investigate this hypothesis in the context of chimpanzee (Pan troglodytes schweinfurthii) sleep site selection, we employed four light traps that we also baited with nontoxic chemical attractants to capture insects throughout the night. Across 74 nights with 294 traps set, we collected 66,545 individual insects. Consistent with the encounter-dilution hypothesis, we found that insect exposure, inferred by absolute numbers of insects caught in nighttime traps, was strongly influenced by the grouping of traps. Specifically, single traps caught more insects—including vector transmitting female mosquitoes—than grouped traps, and the number of insects caught increased with increasing distance between grouped traps. Moreover, ground sleep sites caught fewer insects than arboreal sleep sites. In addition, traps associated with Cynometra alexandri trees resulted in significantly lower catch rates than Pseudospondias microcarpa–associated traps. Our results suggest wild chimpanzees use group sleep as a strategy to avoid biting insects that serve as hosts for vector-borne diseases. [ABSTRACT FROM AUTHOR]

Waterholes are critically important to animal survival in dry habitats but are also a potential source of parasite exposure. Avoiding feces may effectively reduce parasite transmission risk, but may also impose costs, including greater travel distances to locate less contaminated resources. We studied factors influencing wild, water-dependent red-fronted lemurs' (Eulemur rufifrons) selection of waterholes, including factors related to trade-offs between energy expenditure and parasite avoidance. Research took place in a dry deciduous forest in western Madagascar characterized by water scarcity during a pronounced local dry season. We tested whether fecal contamination influenced lemurs' water selection with an experiment that gave lemurs a choice between clean and fecally contaminated water disinfected by boiling. We also monitored lemurs' use of natural waterholes to determine how conspecific fecal contamination and travel distance influenced lemurs' use of waterholes. Red-fronted lemurs displayed a strong preference for clean water in the experiment. At natural waterholes, we found a significant negative interaction between frequency of previous lemur visits and fecal contamination, and a longer return time to waterholes with increasing fecal contamination, revealing that lemurs returned to less contaminated waterholes more frequently and sooner. We also found that lemurs prioritized shorter travel distances over feces avoidance. Together, these results suggest that red-fronted lemurs exercised their preferences for avoiding parasite risk in their natural waterhole choices by avoiding highly contaminated waterholes, especially when waterholes were equidistant. Thus, fecal contamination and travel distance influence water selection in water-scarce habitats, with potential impacts on habitat use and ecological interactions. Significance statement: Animals can take many measures to avoid becoming infected with parasites. One strategy involves avoiding reliable indicators of parasite presence, such as feces. Although avoiding feces may have many benefits, it may also have costs, such as when essential resources, like waterholes in a dry forest, inevitably become contaminated by the animals that use them. Using a choice experiment, we demonstrated that wild red-fronted lemurs preferred to avoid fecal contamination of water sources. From observations of lemurs' waterhole choices, we determined that lemurs exercised this preference most when choosing among nearby waterholes, thus prioritizing energy conservation, and secondarily reducing the costs of parasite exposure risk. Avoidance of feces may thus have effects on lemurs' patterns of habitat use and ecological interactions. [ABSTRACT FROM AUTHOR]

Primates spend almost half their lives asleep, yet little is known about how sleep influences their waking cognition. We hypothesized that diurnal and cathemeral lemurs differ in their need for consistent, non-segmented sleep for next-day cognitive function—including long-term memory consolidation, self-control, foraging efficiency, and sociality. Specifically, we expected that strictly diurnal Propithecus is more reliant on uninterrupted sleep for cognitive performance, as compared to four other lemur species that are more flexibly active (i.e., cathemeral). We experimentally inhibited sleep and tested next-day performance in 30 individuals of 5 lemur species over 960 total nights at the Duke Lemur Center in Durham, North Carolina. Each set of pair-housed lemurs experienced a sleep restriction and/or deprivation protocol and was subsequently tested in a variety of fitness-relevant cognitive tasks. Within-subject comparisons of performance on these tasks were made by switching the pair from the experimental sleep inhibited condition to a normal sleep environment, thus ensuring cognitive equivalency among individuals. We validated effectiveness of the protocol via actigraphy and infrared videography. Our results suggest that 'normal' non-disrupted sleep improved memory consolidation for all lemurs. Additionally, on nights of normal sleep, diurnal lemurs performed better in foraging efficiency tasks than cathemeral lemurs. Social behaviors changed in species-specific ways after exposure to experimental conditions, and self-control was not significantly linked with sleep condition. Based on these findings, the links between sleep, learning, and memory consolidation appear to be evolutionarily conserved in primates. [ABSTRACT FROM AUTHOR]

Sleep is a critically important dimension of primate behavior, ecology, and evolution, yet primate sleep is under-studied because current methods of analyzing sleep are expensive, invasive, and time-consuming. In contrast to electroencephalography (EEG) and actigraphy, videography is a cost-effective and non-invasive method to study sleep architecture in animals. With video data, however, it is challenging to score subtle changes that occur in different sleep states, and technology has lagged behind innovations in EEG and actigraphy. Here, we applied Eulerian videography to magnify pixels relevant to scoring sleep from video, and then compared these results to analyses based on actigraphy and standard infrared videography. We studied four species of lemurs (Eulemur coronatus, Lemur catta, Propithecus coquereli, Varecia rubra) for 12-h periods per night, resulting in 6480 1-min epochs for analysis. Cramer's V correlation between actigraphy-classified sleep and infrared videography-classified sleep revealed consistent results in eight of the nine 12-h videos scored. A sample of the infrared videography was then processed by Eulerian videography for movement magnification and re-coded. A second Cramer's V correlation analysis, between two independent scorers coding the same Eulerian-processed video, found that interobserver agreement among Eulerian videography increased sleep vs. awake, NREM, and REM classifications by 7.1%, 46.7%, and 34.3%, respectively. Furthermore, Eulerian videography was more strongly correlated with actigraphy data when compared to results from standard infrared videography. The increase in agreement between the two scorers indicates that Eulerian videography has the potential to improve the identification of sleep states in lemurs and other primates, and thus to expand our understanding of sleep architecture without the need for EEG. [ABSTRACT FROM AUTHOR]

Attempts to establish relationships between mandibular morphology and either traditional dietary categories or geometric and material properties of primate diets have not been particularly successful. Using our conceptual framework of the feeding factors impacting mandibular morphology, we argue that this is because dietary categories and food geometric and material properties affect mandibular morphology only through intervening variables that are currently poorly understood, i.e., feeding behavior, mandibular loading, and stress and strain regimes. Our studies of 3-dimensional jaw kinematics in macaques and capuchins show that, although jaw movement profiles during chewing are affected by food material properties and species-level effects, patterns of jaw movements in these two species are broadly similar. However, because mandibular loading, stress, and strain regimes are determined by interactions between feeding behavior (such as jaw kinematics) and mandibular morphology, it is difficult to say whether these similarities in chewing kinematics also mean similarities in loading, stress, and strain. Comparative analyses of the scaling of daily feeding time and chew cycle duration reveal only weak support for the hypothesis that larger primates chew more than smaller primates. Consideration of these results suggests that better data are needed on the relationship between dietary categories, food material and geometric properties, the amount of time/cycles associated with different feeding behaviors (ingestion, premolar biting, mastication), and mandible stress and strain patterns if we are to understand fully relationships between mandibular morphology and diet in primates. [ABSTRACT FROM AUTHOR]

Experiments in captivity have provided evidence for social learning, but it remains challenging to demonstrate social learning in the wild. Recently, we developed network-based diffusion analysis (NBDA; 2009) as a new approach to inferring social learning from observational data. NBDA fits alternative models of asocial and social learning to the diffusion of a behavior through time, where the potential for social learning is related to a social network. Here, we investigate the performance of NBDA in relation to variation in group size, network heterogeneity, observer sampling errors, and duration of trait diffusion. We find that observation errors, when severe enough, can lead to increased Type I error rates in detecting social learning. However, elevated Type I error rates can be prevented by coding the observed times of trait acquisition into larger time units. Collectively, our results provide further guidance to applying NBDA and demonstrate that the method is more robust to sampling error than initially expected. Supplemental materials for this article may be downloaded from http:// lb.psychonomic-journals.orglcontent/supplemental. [ABSTRACT FROM AUTHOR]

Emerging infectious diseases threaten a wide diversity of animals, and important questions remain concerning disease emergence in socially structured populations. We developed a spatially explicit simulation model to investigate whether—and under what conditions—disease-related mortality can impact rates of pathogen spread in populations of polygynous groups. Specifically, we investigated whether pathogen-mediated dispersal (PMD) can occur when females disperse after the resident male dies from disease, thus carrying infections to new groups. We also examined the effects of incubation period and virulence, host mortality and rates of background dispersal, and we used the model to investigate the spread of the virus responsible for Ebola hemorrhagic fever, which currently is devastating African ape populations. Output was analyzed using regression trees, which enable exploration of hierarchical and non-linear relationships. Analyses revealed that the incidence of disease in single-male (polygynous) groups was significantly greater for those groups containing an average of more than six females, while the total number of infected hosts in the population was most sensitive to the number of females per group. Thus, as expected, PMD occurs in polygynous groups and its effects increase as harem size (the number of females) increases. Simulation output further indicated that population-level effects of Ebola are likely to differ among multi-male-multi-female chimpanzees and polygynous gorillas, with larger overall numbers of chimpanzees infected, but more gorilla groups becoming infected due to increased dispersal when the resident male dies. Collectively, our results highlight the importance of social system on the spread of disease in wild mammals. [ABSTRACT FROM AUTHOR]

Reproductive skew models have been proposed as a unifying framework for understanding animal social systems, but few studies have investigated reproductive skew in a broad evolutionary context. We compiled data on the distribution of mating among males for 31 species of primates and calculated skew indices for each study. We analyzed the determinants of mating skew with phylogenetic comparative methods to investigate two models from reproductive skew theory, the concession model and the tug-of-war model. Mating skew decreased as the number of males increased in multimale groups, suggesting that monopolization of females becomes more difficult when there are more rivals, and therefore supporting the tug-of-war model. We predicted that single males are unable to monopolize receptive females as overlap in female receptivity increases (estrous synchrony) and, as a result, that mating skew decreases. However, we did not find any evidence for a link between female estrous synchrony and male mating skew. Finally, the concession model predicts high skew in male philopatric species relative to species in which males disperse, yet our measures of mating skew showed no significant associations with qualitative scores of male dispersal. More definitive tests of the concession model will require more quantitative measures of relatedness, which are presently unavailable for most primate species in our study. Overall, our results provide support for the tug-of-war model in primates, and the approach developed here can be applied to study comparative patterns of skew in other biological systems. [ABSTRACT FROM AUTHOR]

Parasites are ubiquitous in populations of free-ranging animals and impact host fitness, but virtually nothing is known about the factors that influence patterns of disease risk across species and the effectiveness of behavioral defenses to reduce this risk. We investigated the correlates of malaria infection (prevalence) in Neotropical primates using data from the literature, focusing on host traits involving group size, body mass, and sleeping behavior. Malaria is spread to these monkeys through anopheline mosquitoes that search for hosts at night using olfactory cues. In comparative tests that used two different phylogenetic trees, we confirmed that malaria prevalence increases with group size in Neotropical primates, as suggested by a previous non-phylogenetic analysis. These results are consistent with the hypothesis that larger groups experience increased risk of attack by mosquitoes, and counter to the hypothesis that primates benefit from the encounter-dilution effect of avoiding actively-seeking insects by living in larger groups. In contrast to non-phylogenetic tests, body mass was significant in fewer phylogeny-based analyses, and primarily when group size was included as a covariate. We also found statistical support for the hypothesis that sleeping in closed microhabitats, such as tree holes or tangles of vegetation, reduces the risk of malaria infection by containing the host cues used by mosquitoes to locate hosts. Due to the small number of evolutionary transitions in sleeping behavior in this group of primates, however, this result is considered preliminary until repeated with a larger sample size. In summary, risk of infection with malaria and other vector-borne diseases are likely to act as a cost of living in groups, rather than a benefit, and sleeping site selection may provide benefits by reducing rates of attack by malaria vectors. [ABSTRACT FROM AUTHOR]

As applied to polygynous mammals, the socioecological model assumes that environmental risks and resources determine the spatial and temporal distribution of females, which then sets male strategies for monopolizing fertile matings. The effects of female spatial distribution (i.e., female number) and temporal overlap (female mating synchrony) have been examined in comparative studies of primates, but the relative influence of these two factors on male monopolization potential (the number of males) remains unclear. One particular problem is that female synchrony is more difficult to estimate than female number. This paper uses multivariate statistical methods and three independent estimates of female synchrony to assess the roles of spatial and temporal effects in the context of a phylogenetically corrected dataset. These analyses are based on sensitivity analyses involving a total of four phylogenies, with two sets of branch length estimates for each tree, and one nonphylogenetic analysis in which species values are used (because male behavior may represent a facultative response to the distribution of females). The results show: (1) that breeding seasonality predicts male number (statistically significant in six out of nine sensitivity tests); (2) that expected female overlap, after controlling for female group size using residuals, also accounts for the number of males in primate groups (significant in eight out of nine tests), and (3) that actual estimates of female mating synchrony predict male number, again after correcting for female group size (significant in five out of nine tests). Nonsignificant results are in the predicted direction, and female group size is significant in all statistical tests. These analyses therefore demonstrate an independent influence of female temporal overlap on male monopolization strategies in mammalian social systems. [ABSTRACT FROM AUTHOR]

The original version of this article unfortunately contained a mistake in the authorgroup section. [ABSTRACT FROM AUTHOR]

As predicted by sexual selection theory, males are larger than females in most polygynous mammals, but recent studies found that ecology and life history traits also affect sexual size dimorphism (SSD) through evolutionary changes in either male size, female size, or both. The primates of Madagascar (Lemuriformes) represent the largest group of mammals without male-biased SSD. The eco-evo-devo hypothesis posited that adaptations to unusual climatic unpredictability on Madagascar have ultimately reduced SSD in lemurs after dispersing to Madagascar, but data have not been available for comparative tests of the corresponding predictions that SSD is also absent in other terrestrial Malagasy mammals and that patterns of SSD changed following the colonization of Madagascar. We used phylogenetic methods and new body mass data to test these predictions among the four endemic radiations of Malagasy primates, carnivorans, tenrecs, and rodents. In support of our prediction, we found that male-biased SSD is generally absent among all Malagasy mammals. Phylogenetic comparative analyses further indicated that after their independent colonization of Madagascar, SSD decreased in primates and tenrecs, but not in the other lineages or when analyzed across all species. We discuss several mechanisms that may have generated these patterns and conclude that neither the eco-evo-devo hypothesis, founder effects, the island rule nor sexual selection theory alone can provide a compelling explanation for the observed patterns of SSD in Malagasy mammals. [ABSTRACT FROM AUTHOR]

Exaggerated sexual signals are likely to be shaped by sexual selection, but few studies have examined signal evolution in females. Domb and Pagel have presented support for the hypothesis that individual differences in exaggerated sexual swellings in female primates are reliable indicators of differences in female quality. However, our re-analysis of their data casts doubt on their conclusions. [ABSTRACT FROM AUTHOR]