Declarative referential gesturing in a wild chimpanzee (Pan troglodytes).

Humans are argued to be unique in their ability and motivation to share attention with others about external entities-sharing attention for sharing's sake. Indeed, in humans, using referential gestures declaratively to direct the attention of others toward external objects and events emerges in the first year of life. In contrast, wild great apes seldom use referential gestures, and when they do, it seems to be exclusively for imperative purposes. This apparent species difference has fueled the argument that the motivation and ability to share attention with others is a human-specific trait with important downstream consequences for the evolution of our complex cognition [M. Tomasello, Becoming Human (2019)]. Here, we report evidence of a wild ape showing a conspecific an item of interest. We provide video evidence of an adult female chimpanzee, Fiona, showing a leaf to her mother, Sutherland, in the context of leaf grooming in Kibale Forest, Uganda. We use a dataset of 84 similar leaf-grooming events to explore alternative explanations for the behavior, including food sharing and initiating dyadic grooming or playing. Our observations suggest that in highly specific social conditions, wild chimpanzees, like humans, may use referential showing gestures to direct others' attention to objects simply for the sake of sharing. The difference between humans and our closest living relatives in this regard may be quantitative rather than qualitative, with ramifications for our understanding of the evolution of human social cognition.

Effects of two dentifrices on the surface properties and staining susceptibility of polymer-based materials.

PURPOSE: This study examined the effect of whitening and abrasive regular dentifrices on the surface characteristics and stain susceptibility of polymer-based CAD-CAM blocks subjected to artificial toothbrushing abrasion (TB). MATERIALS AND METHODS: Two resin composite blocks [CeraSmart (CS) and Grandio Blocs (GB)], one polymer-infiltrated ceramic [Vita Enamic (VE)], and one direct resin composite [GrandioSO (RC)] were used to produce 60 specimens. The baseline mass, gloss, roughness, Vickers hardness (Hv), and color were measured after 7 days of water storage. The specimens were then separated into three TB treatment groups (n = 5): water control (C), regular daily dentifrice (R), and whitening dentifrice (W). Measurements were repeated post-TB (20,000 cycles). All specimens were immersed in coffee, and the CIE ΔE00 was measured after 1, 7, and 14 days. Two-way, one-way ANOVA, and Tukey's post hoc tests were performed to determine any significant differences between the materials and TB groups. To determine the stain resistance, repeated measures of ANOVA, one-way ANOVA, and Tukey's post hoc tests were used (α = 0.05). RESULTS: The R and W mass changes were minimal (-3.77 to 3.16 g%). W reduced the gloss of all the materials by 12.6%-65%. All materials in W were slightly rougher (Ra, 0.107-0.144 µm) than those in R (Ra, 0.049-0.072 µm). The ΔE00 ranged from 0.6 to 1.6 in W and 0.4 to 1.4 in R. VE was the hardest material at baseline (Hv = 362), whereas brushing and staining lowered Hv in all TB groups (282.8-300.6). After brushing in W, VE, and RC were more susceptible to coffee stains than were CS and GB. CONCLUSIONS: The whitening dentifrice roughened CAD-CAM specimens, reducing gloss, yet lightened some materials. Polymer-infiltrated ceramic and direct resin composite specimens brushed with abrasive regular or whitening dentifrice resulted in more intense staining than the CAD-CAM resin composites.

Evaluating methods to create protein functionalized catanionic vesicles.

Catanionic surfactant vesicles (SVs) composed of sodium dodecylbenzenesulfonate (SDBS) and cetyltrimethylammonium tosylate (CTAT) have potential applications as targeted drug delivery systems, vaccine platforms, and diagnostic tools. To facilitate these applications, we evaluated various methods to attach proteins to the surface of SDBS/CTAT vesicles. Acid phosphatase from wheat germ was used as a model protein. Acid phosphatase was successfully conjugated to vesicles enriched with a Triton-X 100 derivative containing an unsaturated ester. Enzymatic activity of acid phosphatase attached to vesicles was assessed using an acid phosphatase assay. Results from the acid phosphatase assay indicated that 15 ± 3% of the attached protein remained functional but the presence of vesicles interferes with the assay. DLS and zeta potential results correlated with the protein functionalization studies. Acid phosphatase functionalized vesicles had an average diameter of 175 ± 85 nm and an average zeta potential of -61 ± 5 mV in PBS. As a control, vesicles enriched with Triton-X 100 were prepared and analyzed by DLS and zeta potential measurements. Triton X-100 enriched vesicles had an average diameter of 140 ± 67 nm and an average zeta potential of -49 ± 2 mV in PBS. Functionalizing the surface of SVs with proteins may be a key step in developing vesicle-based technologies. For drug delivery, antibodies could be used as targeting molecules; for vaccine formulation, functionalizing the surface with spike proteins may produce novel vaccine platforms.

The use of chimpanzee-modified faunal assemblages to investigate early hominin carnivory.

Chimpanzees regularly hunt and consume prey smaller than themselves. It seems therefore likely that early hominins also consumed small vertebrate meat before they started using and producing stone tools. Research has focused on cut marks and large ungulates, but there is a small body of work that has investigated the range of bone modifications produced on small prey by chimpanzee mastication that, by analogy, can be used to identify carnivory in pre-stone tool hominins. Here, we review these works along with behavioral observations and other neo-taphonomic research. Despite some equifinality with bone modifications produced by baboons and the fact that prey species used in experiments seldom are similar to the natural prey of chimpanzees, we suggest that traces of chimpanzee mastication are sufficiently distinct from those of other predators that they can be used to investigate mastication of vertebrate prey by early hominins.

Investigating infant feeding development in wild chimpanzees using stable isotopes of naturally shed hair.

Measuring the relative contributions of milk and non-milk foods in the diets of primate infants is difficult from observations. Stable carbon (δ13 C) and nitrogen (δ15 N) isotopes in hair can be used to physiologically track infant feeding through development, but few wild studies have done so, likely due to the difficulty in collecting hair non-invasively. We assessed infant feeding at different ages in wild chimpanzees (Pan troglodytes) at Ngogo, Uganda using δ13 C and δ15 N of keratin in 164 naturally shed hairs from 29 infants (61 hairs), 6 juveniles (7 hairs), 28 mothers (67 hairs) and 14 adult males (29 hairs). Hairs were collected when they stuck to feces during defecation or from the ground after chimpanzees groomed or rested. We could not distinguish between the hairs of infants and mothers using strand length and diameter. Infants 1-2 years old were most enriched in 13 C and 15 N and showed means of 1.1‰ in δ13 C and 2.1‰ in δ15 N above their mothers. Infants at 2 years had hair δ13 C values like those of their mothers, which suggests infants began relying more heavily on plants around this age. While mother-infant δ13 C and δ15 N differences generally decreased with offspring age, as is expected when infants rely increasingly more on independent foraging through development, milk seemed to remain an important dietary component for infants older than 2.5 years, as evidenced by continuing elevated δ15 N. We showed that stable carbon and nitrogen isotopes in naturally shed hairs can feasibly detect trophic level differences between chimpanzee infants and mothers. Since it can mitigate some of the limitations associated with behavioral and fecal stable isotope data, the use of hair stable isotopes is a useful, non-invasive tool for assessing infant feeding development in wild primates.

Male chimpanzee sexual coercion and mating success at Ngogo.

Chimpanzees (Pan troglodytes) have a complex mating system in which both sexes use multiple tactics. Most copulations occur in group contexts, and high-ranking males can gain high mating and reproductive success, but females typically mate with multiple males and the potential for sperm competition is high. Also, male-female dyads sometimes form temporary exclusive mating associations (consortships). Male aggression to receptive females is common. Several studies have supported the hypothesis that this is sexual coercion, but debate exists regarding the importance of coercion relative to that of female choice. The number of adult males in a community can influence the balance between these processes. In the large Ngogo community, male dominance ranks and rates of aggression to fully-swollen females were positively related to mating success as estimated by copulation rates and by proportions of copulations achieved. Aggression rates were higher than at other sites, overall and per male, especially during periovulatory periods, and increased with the number of males associating with a female. Aggression impaired female foraging efficiency. Males initiated most copulations and females rarely refused mating attempts. Male-to-female grooming was positively associated with male mating success and with the proportion of copulations that females initiated, but the amount of grooming was typically small and whether grooming-for-mating trading occurs is uncertain. These results are consistent with the hypothesis that sexual coercion is an important component of male chimpanzee mating strategies in many sociodemographic circumstances, but also show that male tactics vary both in response to and independently of those circumstances.

Earlier spring reduces potential for gene flow via reduced flowering synchrony across an elevational gradient.

PREMISE: One of the best-documented ecological responses to climate warming involves temporal shifts of phenological events. However, we lack an understanding of how phenological responses to climate change vary among populations of the same species. Such variability has the potential to affect flowering synchrony among populations and hence the potential for gene flow. METHODS: To test whether an earlier start of the growing season affects the potential for gene flow among populations, we quantified the distributions of flowering times of two spring-flowering plants (Trillium erectum and Erythronium americanum) over 6 years along an elevational gradient. We developed a novel model-based metric of potential gene flow between pairs of populations to quantify the potential for pollen-mediated gene flow based on flowering phenology. RESULTS: Earlier onset of spring led to greater separation of peak flowering dates across the elevational gradient for both species investigated, but was only associated with a reduction in potential gene flow in T. erectum, not E. americanum. CONCLUSIONS: Our study suggests that climate change could decrease gene flow via phenological separation among populations along climatic gradients. We also provide a novel method for quantifying potential pollen-mediated gene flow using data on flowering phenology, based on a quantitative, more biologically interpretable model than other available metrics.

Real-world effectiveness and safety of ustekinumab for the treatment of Crohn's disease: the Scottish ustekinumab cohort.

BACKGROUND AND AIM: Ustekinumab is a monoclonal antibody that targets interleukin-12/23. In Scotland, it was approved for the treatment of moderate to severe Crohn's disease in 2017. The objective of this study was to establish the real-world effectiveness and safety of ustekinumab in the treatment of Crohn's disease. METHODS: We conducted a retrospective study of patients receiving ustekinumab across eight Scottish National Health Service health boards between 2017 and 2019. Inclusion criteria included a diagnosis of Crohn's disease with symptoms attributed to active disease plus objective signs of inflammation at baseline (C-reactive protein ≥ 5 mg/L or fecal calprotectin ≥ 250 µg/g or inflammation on endoscopy/magnetic resonance imaging) and completion of induction plus at least one clinical follow-up at 8 weeks. Kaplan-Meier survival analysis was used to establish 12-month cumulative rates of clinical remission, mucosal healing, deep remission, and perianal fistula response. Rates of serious adverse events were described quantitatively. RESULTS: Our cohort consisted of 216 patients (female sex, 37.9%; median age, 39.0 years, interquartile range [IQR] 28.8-51.8 years; disease duration, 9.9 years, IQR 6.0-16.5 years; prior biologic, 98.6%) with a median follow-up of 35.0 weeks (IQR 17.4-52.0 weeks). Twelve-month cumulative rates of clinical remission, mucosal healing, and deep remission (clinical remission plus mucosal healing) were 32.0%, 32.7%, and 19.3%, respectively. In patients with active perianal disease (n = 37), the 12-month cumulative perianal response rate was 53.1%. The serious adverse event rate was 13.6 per 100 patient-years of follow-up. CONCLUSION: Ustekinumab is a safe and effective treatment for the treatment of complex Crohn's disease.

Relationship Between Tennis Serve Velocity and Select Performance Measures.

ABSTRACT: Hayes, MJ, Spits, DR, Watts, DG, and Kelly, VG. Relationship between tennis serve velocity and select performance measures. J Strength Cond Res 35(1): 190-197, 2021-The purpose of this study was to determine whether there was a relationship between tennis serve speed and isometric midthigh pull (IMTP) kinetic variables: countermovement jump (CMJ) height, shoulder internal and external rotation strength, and anthropometric measures in elite adolescent tennis players. Twenty-one elite junior tennis players from the Tennis Australia National Academy were recruited for this study (male, n = 12 and female, n = 9). Correlations between the performance variables and peak tennis serve speed were calculated using a Pearson's product-moment correlation coefficient. A significant positive correlation was found between peak serve speed and body height (r = 0.80, p < 0.01), IMTP peak force (r = 0.87, p < 0.01), CMJ height (r = 0.77, p ≤ 0.01), and impulse at 300 ms (r = 0.71, p ≤ 0.01). A significant, strong correlation was found between peak serve speed and impulse at 100 ms (r = 0.58, p ≤ 0.01), impulse at 200 ms (r = 0.64, p ≤ 0.01), internal rotation <90° (r = 0.63, p ≤ 0.01), and external rotation <90° (r = 0.63, p ≤ 0.01). Because of the significant positive correlations between IMTP variables, CMJ height and peak serve speed, strength and conditioning coaches with access to a force plate should consider using the IMTP to athletically profile athletes in regards to their strength, power, and injury risk.

Meat eating by nonhuman primates: A review and synthesis.

Most nonhuman primates prey on vertebrates. Meat-eating, defined as ingestion of vertebrate tissue, occurs in 12 families, ≥39 genera, and ≥89 species. It is most common in capuchins (Cebus and Sapajus spp.), baboons (Papio spp.), bonobos (Pan paniscus), and chimpanzees (Pan troglodytes) and modestly common in blue monkeys (Cercopithecus mitis), callitrichids (Callithrix spp. and Saguinus spp.), and squirrel monkeys (Saimiri spp.). It is uncommon in other cercopithecines, rare in other haplorhines and in lemurs, and virtually absent in colobines. Birds are the prey class eaten by the most species (≥53), followed by reptiles (≥48), amphibians (≥38), mammals (≥35), and fish (≥7). Major hypotheses for the importance of meat eating are that it is (1) mainly an energy source, especially (1a) when plant-source foods (PSFs) with high energy return rates are scarce (energy shortfall hypothesis); (2) mainly a protein source; and (3) mainly a source of micronutrients scarce in PSFs. Meat eating bouts sometimes provide substantial energy and protein, and some chimpanzees gain substantial protein from meat monthly or annually. However, meat typically accounts for only small proportions of feeding time and of total energy and protein intake, and quantitative data are inconsistent with the energy shortfall hypothesis. PSFs and/or invertebrates are presumably the main protein sources, even for chimpanzees. Support is strongest for the micronutrient hypothesis. Most chimpanzees eat far less meat than recorded for hunter-gatherers, but the highest chimpanzee estimates approach the lowest for African hunter-gatherers. In fundamental contrast to the human predatory pattern, other primates only eat vertebrates much smaller than they are, tool-assisted predation is rare except in some capuchins and chimpanzees, and tool use in carcass processing is virtually absent. However, harvesting of small prey deserves more attention with reference to the archaeological and ethnographic record.

Premasticated food transfer by wild chimpanzee mothers with their infants: Effects of maternal parity, infant age and sex, and food properties.

Premasticated food transfer, when an individual partially breaks down food through chewing and feeds it to another individual, usually mouth-to-mouth, is described widely across human cultures. This behavior plays an important role in modern humans' strategy of complementary feeding, which involves supplementing maternal milk in infant diets with processed, easily digestible versions of adult foods. The extent to which other primates engage in premasticated food transfer with infants is unclear, as premasticated food transfers have been only occasionally reported in other ape species. We investigated premasticated food transfers in 62 mother-infant pairs of wild chimpanzees at Ngogo, Uganda, as well as unresisted food taking, when mothers passively allow infants to seize food. We evaluated the presence or absence and rates of premasticated food transfer and unresisted food taking relative to maternal parity and infant age and sex and assessed the food species and part used. We found that chimpanzee mothers regularly shared premasticated food with their infants aged between 6 months and 4 years, but they were more likely to share, and more frequently shared, with younger infants. The frequency with which females shared premasticated food may relate to maternal experience, as multiparous females shared premasticated food more often than did first-time mothers, which we did not find with unresisted food taking. Both easy-to-chew, commonly eaten foods and tougher, rarely eaten foods were shared. Premasticated food transfer and unresisted food taking may be infant-rearing strategies to facilitate the transition from a diet of exclusive maternal milk to solid food during early infancy. Premasticated food transfer in particular may provide energetic, immune, or growth benefits to infants through reduced chewing effort and maternal saliva. Given our findings in chimpanzees and earlier reports in other ape species, we suggest that the foundation of complementary feeding, a uniquely hominin strategy, might have been present in a common ancestor shared with the other great apes in the form of premasticated, mouth-to-mouth food transfer by mothers with their offspring.

Key viral immune genes and pathways identify elite athletes with URS.

PURPOSE: Habitual intense exercise may increase the incidence of upper respiratory symptoms (URS) in elite athletes. This study investigated whether immune gene expression could identify gene markers that discriminate athletes with a higher prevalence of URS. METHODS: This cross-sectional analysis of elite Australian athletes from various sports investigated whether athletes retrospectively reporting URS for two days or more in a month (n=38), had an altered immune gene expression profile compared with asymptomatic athletes (n=33). Peripheral blood samples were collected during Olympic selection events with corresponding URS data collected for the one-month period before sampling. Digital immune gene expression analysis was undertaken using the NanoString PanCancer Immune Profiling panel. RESULTS: Fifty immune genes were differentially expressed between the groups (p<0.05) and approximately 78% of these genes were more highly expressed in athletes reporting URS. Many of these genes were interferon-stimulated genes or genes involved in the Jak/Stat signalling pathway. Only interferon alpha inducible protein 27 (IFI27), an interferon stimulated gene involved in viral response, remained significantly higher in athletes reporting URS (log2 fold-difference=2.49, odds ratio 1.02 per unit increase; p<0.01) post-adjustment and discriminated athletes reporting URS from asymptomatic athletes with 78% accuracy. CONCLUSIONS: Expression of IFI27 could differentiate athletes reporting URS from asymptomatic athletes, a gene that is upregulated in the immune response to viral infection. Upregulation of viral signalling pathways provides novel information on the potential aetiology of URS in elite Olympic athletes.

Lethal aggression in Pan is better explained by adaptive strategies than human impacts.

Observations of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) provide valuable comparative data for understanding the significance of conspecific killing. Two kinds of hypothesis have been proposed. Lethal violence is sometimes concluded to be the result of adaptive strategies, such that killers ultimately gain fitness benefits by increasing their access to resources such as food or mates. Alternatively, it could be a non-adaptive result of human impacts, such as habitat change or food provisioning. To discriminate between these hypotheses we compiled information from 18 chimpanzee communities and 4 bonobo communities studied over five decades. Our data include 152 killings (n = 58 observed, 41 inferred, and 53 suspected killings) by chimpanzees in 15 communities and one suspected killing by bonobos. We found that males were the most frequent attackers (92% of participants) and victims (73%); most killings (66%) involved intercommunity attacks; and attackers greatly outnumbered their victims (median 8:1 ratio). Variation in killing rates was unrelated to measures of human impacts. Our results are compatible with previously proposed adaptive explanations for killing by chimpanzees, whereas the human impact hypothesis is not supported.

Long-term trends in fruit production in a tropical forest at Ngogo, Kibale National Park, Uganda.

Fruit production in tropical forests varies considerably in space and time, with important implications for frugivorous consumers. Characterizing temporal variation in forest productivity is thus critical for understanding adaptations of tropical forest frugivores, yet long-term phenology data from the tropics, in particular from African forests, are still scarce. Similarly, as the abiotic factors driving phenology in the tropics are predicted to change with a warming climate, studies documenting the relationship between climatic variables and fruit production are increasingly important. Here we present data from 19 years of monitoring the phenology of 20 tree species at Ngogo in Kibale National Park, Uganda. Our aims were to characterize short- and long-term trends in productivity and to understand the abiotic factors driving temporal variability in fruit production. Short-term (month-to-month) variability in fruiting was relatively low at Ngogo, and overall fruit production increased significantly through the first half of the study. Among the abiotic variables we expected to influence phenology patterns (including rainfall, solar irradiance, and average temperature), only average temperature was a significant predictor of monthly fruit production. We discuss these findings as they relate to the resource base of the frugivorous vertebrate community inhabiting Ngogo.

Group augmentation, collective action, and territorial boundary patrols by male chimpanzees.

How can collective action evolve when individuals benefit from cooperation regardless of whether they pay its participation costs? According to one influential perspective, collective action problems are common, especially when groups are large, but may be solved when individuals who have more to gain from the collective good or can produce it at low costs provide it to others as a byproduct. Several results from a 20-y study of one of the most striking examples of collective action in nonhuman animals, territorial boundary patrolling by male chimpanzees, are consistent with these ideas. Individuals were more likely to patrol when (i) they had more to gain because they had many offspring in the group; (ii) they incurred relatively low costs because of their high dominance rank and superior physical condition; and (iii) the group size was relatively small. However, several other findings were better explained by group augmentation theory, which proposes that individuals should bear the short-term costs of collective action even when they have little to gain immediately if such action leads to increases in group size and long-term increases in reproductive success. In support of this theory, (i) individual patrolling effort was higher and less variable than participation in intergroup aggression in other primate species; (ii) males often patrolled when they had no offspring or maternal relatives in the group; and (iii) the aggregate patrolling effort of the group did not decrease with group size. We propose that group augmentation theory deserves more consideration in research on collective action.

Nudging, formulating new products, and the lifecourse: A qualitative assessment of the viability of three methods for reducing Scottish meat consumption for health, ethical, and environmental reasons.

Most governmental initiatives designed to improve dietary and planetary health have adopted a light-touch informing approach. However, it may be necessary to consider more direct measures that go beyond simply informing the public if the current high levels of meat consumption in Scotland are to be addressed. This paper considers three possible avenues through which more sustainable meat consumption patterns may be promoted: 'nudging', the formulation of new meat-alternative products, and targeting those in particular stages of the lifecourse. Through focus groups held in various locations in Scotland, the perceived viability of these measures was explored. While each measure shows some promise for reducing Scottish meat intake, the complex nature of food choice means that more qualitative research into meat consumption in Scotland is required.

Prevalence of illness, poor mental health and sleep quality and low energy availability prior to the 2016 Summer Olympic Games.

OBJECTIVE: Establish the prevalence of illness symptoms, poor sleep quality, poor mental health symptoms, low energy availability and stress-recovery state in an Olympic cohort late in the 3 months prior to the Summer Olympic Games. METHODS: Olympic athletes (n=317) from 11 sports were invited to complete questionnaires administered 3 months before the Rio 2016 Olympic Games. These questionnaires included the Depression, Anxiety and Stress Questionnaire, Perceived Stress Scale, Dispositional Resilience Scale, Recovery-Stress Questionnaire (REST-Q-52 item), Low Energy Availability in Females Questionnaire (LEAF-Q), Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index and custom-made questionnaires on probiotic usage and travel. Multiple illness (case) definitions were applied. ORs and attributable fractions in the population were used. Factor analyses were used to explore the relationships between variables. RESULTS: The response rate was of 42% (male, n=47, age 25.8±4.1 years; female, n=85, age 24.3±3.9 years). Low energy availability was associated with sustaining an illness in the previous month (upper respiratory, OR=3.8, 95% CI 1.2 to 12). The main factor relating to illness pertained to a combination of anxiety and stress-recovery states (as measured by the REST-Q-52 item). All participants reported at least one episode of illness in the last month (100% prevalence). CONCLUSIONS: All participants reported at least one illness symptom in the previous month. Low energy availability was a leading variable associated with illness in Olympic-class athletes. The estimates duration of symptoms ranged from 2 to 7 days. Factor analyses show the interdependence of various health domains and support multidisciplinary care.

Favorable ecological circumstances promote life expectancy in chimpanzees similar to that of human hunter-gatherers.

Demographic data on wild chimpanzees are crucial for understanding the evolution of chimpanzee and hominin life histories, but most data come from populations affected by disease outbreaks and anthropogenic disturbance. We present survivorship data from a relatively undisturbed and exceptionally large community of eastern chimpanzees (Pan troglodytes schweinfurthii) at Ngogo, Kibale National Park, Uganda. We monitored births, deaths, immigrations, and emigrations in the community between 1995 and 2016. Using known and estimated ages, we calculated survivorship curves for the whole community, for males and females separately, and for individuals ≤2 years old when identified. We used a novel method to address age estimation error by calculating stochastic survivorship curves. We compared Ngogo life expectancy, survivorship, and mortality rates to those from other chimpanzee communities and human hunter-gatherers. Life expectancy at birth for both sexes combined was 32.8 years, far exceeding estimates of chimpanzee life expectancy in other communities, and falling within the range of human hunter-gatherers (i.e., 27-37 years). Overall, the pattern of survivorship at Ngogo was more similar to that of human hunter-gatherers than to other chimpanzee communities. Maximum lifespan for the Ngogo chimpanzees, however, was similar to that reported at other chimpanzee research sites and was less than that of human-hunter gatherers. The absence of predation by large carnivores may contribute to some of the higher survivorship at Ngogo, but this cannot explain the much higher survivorship at Ngogo than at Kanyawara, another chimpanzee community in the same forest, which also lacks large carnivores. Higher survivorship at Ngogo appears to be an adaptive response to a food supply that is more abundant and varies less than that of Kanyawara. Future analyses of hominin life history evolution should take these results into account.

Multiple testing with heterogeneous multinomial distributions.

Standard false discovery rate (FDR) procedures can provide misleading inference when testing multiple null hypotheses with heterogeneous multinomial data. For example, in the motivating study the goal is to identify species of bacteria near the roots of wheat plants (rhizobacteria) that are moderately or strongly associated with productivity. However, standard procedures discover the most abundant species even when their association is weak and fail to discover many moderate and strong associations when the species are not abundant. This article provides a new FDR-controlling method based on a finite mixture of multinomial distributions and shows that it tends to discover more moderate and strong associations and fewer weak associations when the data are heterogeneous across tests. The new method is applied to the rhizobacteria data and performs favorably over competing methods.