Intraspecific agonism plays a role in accessing key resources for survival and reproduction, such as food and mates, in many nonhuman primates. Female dominance and fission-fusion dynamics (i.e., fluctuating subgroup size and composition) are two adaptive strategies used by some primate species to cope with a high degree of seasonality. We investigated how seasonal fluctuations in reproductive opportunities and food availability affect group-wide agonism rates in wild black-and-white ruffed lemurs (Varecia variegata), a species with high fission-fusion dynamics and female dominance that exhibits strict seasonal and communal breeding but does not consistently breed annually. We conducted focal animal sampling over four years, encompassing several mating and birth seasons for V. variegata across two sites. We summed all agonistic interactions within the focal animal’s subgroup to calculate biweekly agonism rates. We estimated fruit and flower abundance using semimonthly phenological surveys. We found a significant effect of reproductive season on agonism, such that agonism rates were highest during the mating season (vs. nonreproductive and birth seasons), particularly in years when mating and births were observed. Subgroup size was also a major driver of agonism, with higher rates of agonism in larger subgroups, although subgroup size did not significantly affect individual rates of agonism. Fruit and flower availabilities were not significant predictors of agonism, suggesting that agonistic interactions in V. variegata may be mitigated by other means such as fission-fusion dynamics. Overall, these findings suggest that agonism functions as a reproductive strategy in V. variegata, and potentially in other female-dominant or communally breeding primate species, as a mechanism for females to exert mate choice and for males to gain access to mating opportunities.
Aye-ayes possess an unusual suite of morphological characteristics that are used to locate and extract xylophagous invertebrates. A growing body of evidence supports the long-held claim that xylophagous invertebrates comprise a significant portion of aye-aye diets; however, several aye-aye features are also used to harvest endosperm from seeds of Canarium spp., another important aye-aye resource. Using continuous focal animal sampling, we collected feeding data on a female aye-aye in Madagascar's Ihofa Forest from January 2016 to December 2017 to better elucidate resource preference. We used aye-aye feeding traces in woody substrates as a proxy for xylophagous invertebrate presence to estimate xylophagous invertebrate abundance along 20 transects (10 m × 100 m). During observational follows, we also counted each trace made during feeding. Using the same transects, we also estimated Canarium seed abundance based on fruit in the canopy and fruit on the ground. There were more aye-aye feeding traces in woody substrates for xylophagous invertebrates (3206) than for Canarium seeds (2153). A Wilcoxon signed-rank test found no significant difference in the number of xylophagous invertebrates and Canarium seeds consumed during this study ( p = 0.317); however, a two-item preference index indicated that xylophagous invertebrates were the preferred resource monthly and annually. Our results indicated that the aye-aye in this study preferentially consumed xylophagous invertebrates. This provides further evidence that the aye-aye's highly derived morphology is specifically adapted for extracting insect larvae from structurally defended substrates. The use of some of these morphological autapomorphies for Canarium seed feeding may be an example of an exaptation.
Food transfer occurs when part or all of a food item is passed from one individual to another. Adult transfer of solid food to infants has been reported in 45 primate species. For aye-ayes, this behaviour was recorded in captivity where individuals were provisioned, but little is known about this behaviour in the wild. Wild aye-ayes consume hard-to-process foods that are inaccessible to infants such as wood-boring larvae embedded in trees and the endosperm of Canarium spp. seeds which are protected by a hard coat. Learning to process these food resources may be essential for aye-aye development. We used ad libitum sampling to record the social activities and behaviours of a mother and her male infant from January to December 2020 in Sangasanga Forest, Kianjavato, Madagascar. We collected in total 4 hours 57 minutes and 57 seconds of social behaviours. Over two days in December, we observed eight occurrences of the 11-month-old infant usurping Canarium sp. seeds from his mother. Our findings suggest that, due to physical limitations, the infant aye-aye primarily resorted to food transfer via theft to obtain hard-to-process food. Transfer of larvae, their main resource, was not observed, though it may occur until young aye-aye have the bite force needed to gouge holes in substrates and the coordination to retrieve and extract wood-boring larvae. Future research should explore if food transfer differs across individuals' sex, sites and type of food as well as the effects of anthropogenic disturbances on foraging.
How plants respond to weather seasonality is a fundamental evolutionary question that is particularly relevant to understand as climate change alters weather patterns across the globe. Although temperature and light conditions primarily cue flowering in temperate plants, the weather cues that tropical plants use to regulate their phenological cycles are lesser known. We studied the weather‐related ultimate causes of flowering and fruiting patterns in six woody perennial species found in the evergreen lowland humid forests of southeastern Madagascar by investigating the associations between biweekly weather (i.e. rainfall, temperature and insolation) and species‐level flowering and fruiting phenology. We then developed process‐based models to identify the potential proximate weather cues that these species use to regulate their flowering time. Given the region's strong rainfall seasonality, we hypothesised that the reproductive timing of these species would mainly be constrained by water availability. These species flowered asynchronously, at different times of the year and after a variety of weather conditions, including drought, cool temperatures, warm temperatures and low light. The flowering and fruiting patterns of only two species suggested that water stress constrained their phenology in support of the water limitation and optimal time of germination hypotheses. The flowering patterns of these six species did not align with the insolation limitation hypothesis, providing no evidence to suggest that light stress constrained their phenology. Cool temperature was most likely a proximate flowering cue for only one of these perennial tropical species, which contrasts with the ubiquitous influence that low temperatures have on temperate flowering phenology. Light limitation most likely influenced the flowering time of two species, paralleling the photoperiod flowering cues that some temperate plants use. The timescales at which these potential flowering cues operated were species‐specific, spanning 1–7 months. Synthesis . The diverse associations we identified between weather and flowering patterns suggest that the phenology of these perennial tropical plants evolved in response to different selective pressures and will likely have variable responses to climate change.
This study examines the contribution of a contextualized Christian ecological ethics to local responses to climate change challenges in Madagascar. The research focuses on the rural commune of Mahereza, a community deeply rooted in Christian faith and reliant on subsistence agriculture. The methodology combines biblical exegesis, field surveys, and the integration of Malagasy national environmental policies. Findings highlight a strong spiritual sense of responsibility toward creation, yet reveal a gap between this conviction and the adoption of sustainable agricultural practices. This discrepancy is primarily driven by economic, technical, and structural constraints, which limit the implementation of Christian ecological principles. The proposed ethical framework unfolds in three stages: repentance, transformation of perspective, and concrete commitment inspired by the Servant Christ. It fosters an alliance between faith, local knowledge, and agroecological innovations to reconcile agricultural productivity with the safeguarding of creation. Churches, in collaboration with the state, NGOs, and academic institutions, can play a strategic role in this transition. Ultimately, this approach promotes dialogue between faith, science, and policy, framing ecology as both a space for spiritual conversion and collective transformation.
