Dietary flexibility of the greater bamboo lemur (Prolemur simus), a specialized feeder, in eastern Madagascar.

The degree of dietary flexibility in primates is species specific; some incorporate a wider array of resources than others. Extreme interannual weather variability in Madagascar results in seasonal resource scarcity which has been linked to specialized behaviors in lemurs. Prolemur simus, for example, has been considered an obligate specialist on large culm bamboo with >60% of its diet composed of woody bamboos requiring morphological and physiological adaptations to process. Recent studies reported an ever-expanding list of dietary items, suggesting that this species may not be an obligate specialist. However, long-term quantitative feeding data are unavailable across this species' range. To explore the dietary flexibility of P. simus, we collected data at two northern sites, Ambalafary and Sahavola, and one southern site, Vatovavy, from September 2010 to January 2016 and May 2017 to September 2018, respectively. In total, we recorded 4022 h of behavioral data using instantaneous sampling of adult males and females from one group in Ambalafary, and two groups each in Sahavola and Vatovavy. We recorded 45 plant species eaten by P. simus over 7 years. We also observed significant differences in seasonal dietary composition between study sites. In Ambalafary, bamboo was the most frequently observed resource consumed (92.2%); however, non-bamboo resources comprised nearly one-third of the diet of P. simus in Sahavola and over 60% in Vatovavy. Consumption of all bamboo resources increased during the dry season at Ambalafary and during the wet season at Vatovavy, but never exceeded non-bamboo feeding at the latter. Culm pith feeding was only observed at Ambalafary, where it was more common during the dry season. We identify P. simus as a bamboo facultative specialist capable of adjusting its feeding behavior to its environment, indicating greater dietary flexibility than previously documented, which may enable the species to survive in increasingly degraded habitats.

Possible Infanticidal Event of an Aye-Aye (Daubentonia madagascariensis) in Torotorofotsy, Madagascar.

Infanticide occurs in an array of mammalian species, especially primates. Most infanticidal events occur in polygynous societies, though they sometimes happen in nongregarious populations. We witnessed a possible infanticidal event of a 3-month-old male aye-aye, a species that exhibits a dispersed multimale social system, in Torotorofotsy, Madagascar. Though firsthand killing of the infant was not observed, physical injuries to the infant, vocalizations of the adult female, and her subsequent chase of the adult male aye-aye strongly indicates infanticide. If true, this would be the first recorded incident of an infanticidal event in a noyau primate. The evidence for three different explanations of infanticide is evaluated.

Locomotion of an adult female and juvenile male aye-aye (Daubentonia madagascariensis) in Torotorofotsy, Madagascar.

Aye-ayes (Daubentonia madagascariensis) locate and acquire invertebrates from within woody substrates at all levels of the rainforest; yet how their locomotion helps them accommodate this diet has not been explored in detail. We studied the locomotor behavior of an adult female (N = 1,085) and juvenile male (N = 708) aye-aye in the undisturbed forest of Torotorofotsy, Madagascar from May to December 2017. We used bout sampling to record locomotion during foraging and travel of the two radio-collared individuals. We used χ 2 tests to compare overall locomotion, travel, and foraging, as well as strata and support use. We performed a correspondence analysis to examine relationships between individual behaviors, strata, and support types. Leaping accounted for 47.9% and 50.1% of all locomotor activity in the adult female and juvenile male, respectively. Leaping was the most common behavior during travel in both individuals (59.2% and 53.9%, respectively), whereas head-first descent was most frequent during foraging (35.0% and 48.0%, respectively). For all three locomotor categories, the main canopy (40.3%-79.6%) was used most frequently and trunks were the most frequently used support type (50.7%-60.0%). There is a strong association between strata and support use overall and during travel. Quadrupedal walking was significantly associated with the main canopy, as was head-first descent with the low canopy. Our analysis demonstrates that aye-ayes use a variety of locomotor behaviors to forage for invertebrates. Aye-ayes' ability to repurpose their positional repertoire to acquire other resources in degraded forests should not obscure the importance of invertebrates to this species.

Home Range Size and Seasonal Variation in Habitat Use of Aye-Ayes (Daubentonia madagascariensis) in Torotorofotsy, Madagascar.

Madagascar's dramatic climatic fluctuations mean most lemurs adjust behaviors seasonally as resource availability fluctuates. Many lemurs will adopt one of two strategies, a resource maximizer or an area minimizer, when adjusting to seasonal shifts in resource availability. However, it is unknown if and how aye-aye (Daubentonia madagascariensis) ranging behavior is influenced by seasonality. We explored whether habitat use changed seasonally. We followed two aye-ayes, an adult male and an adult female, in the undisturbed forest of Torotorofotsy, Madagascar, from April 2012 to December 2017. We used instantaneous focal-animal sampling to collect behavioral data every 5 min and GPS locations every 20 min. We used the minimum convex polygon (MCP) to determine overall home range, and the Brownian bridge movement model (BBMM) to estimate overall and seasonal home range of the female aye-aye from November 2014 to October 2017. We used Wilcoxon signed-rank tests to determine whether there were significant differences in home range sizes between seasons across years and to examine whether there were seasonal differences in height of invertebrate foraging, generalized linear models to assess seasonal differences in travel rates and nesting locations, and χ2 tests to determine whether there were differences in forest strata use when foraging on invertebrates. The male's MCP home range was 2,586 ha, and the female's MCP home range was 765 ha. The seasonal BBMM for the female varied between 443.6 and 1,010.0 ha, though infant rearing appears to have influenced these values. There were no significant differences in seasonal home range, travel rates, nesting locations, or height of invertebrate feeding. However, canopy level invertebrate foraging occurred more often than understory or ground levels. It appears aye-ayes in this undisturbed forest were not influenced by seasonal shifts and had larger home ranges than any previously reported. These findings may indicate that aye-ayes in an undisturbed forest are resource maximizers, closely linked to invertebrate assemblages.

Re-assessing the applicability of the Jarman/Bell model and Kay's threshold to the insectivorous aye-aye (Daubentonia madagascariensis).

OBJECTIVES: Jarman/Bell principle and Kay's threshold suggest that large animals should not be able to sustain themselves on insects. However, animals with specialized morphological and/or behavioral adaptations violate these assumptions. Male aye-ayes were recently identified as having an insectivorous diet despite weighing 2.5 kg. We further explored this diet/body size disparity by studying behaviors of an adult female and juvenile male aye-aye. MATERIALS AND METHODS: We collected behavioral data on an adult female and juvenile male aye-aye in Torotorofotsy, Madagascar from January 2016 to December 2017. We used instantaneous sampling to determine the frequency of feeding events and continuous sampling during feeding behaviors to assess duration of feeding bouts. RESULTS: Invertebrates comprised over 88% of the diet for both animals. A Wilcoxon signed-rank test found no significant difference in the female's feeding frequencies between the hot/rainy seasons and the cold/dry seasons. DISCUSSION: Our results support earlier findings that invertebrates are the aye-aye's main resource and corroborate that aye-ayes violate assumptions of the Jarman/Bell model and Kay's threshold. We suggest that the Jarman/Bell principle and Kay's threshold be used as supporting evidence and not to repudiate findings that do not conform to these guidelines.

Behaviour and Ecology of Male Aye-Ayes (Daubentonia madagascariensis) in the Kianjavato Classified Forest, South-Eastern Madagascar.

Previous studies found that aye-ayes (Daubentonia madagascariensis) consume a variety of non-invertebrate resources, supporting the hypothesis that aye-ayes are too large-bodied to focus feeding efforts on insects. However, these conclusions were based on introduced populations, with little known about aye-aye behaviour and ecology in its natural habitat. This study investigates activity budgets, diet, and home range/territories of 2 male aye-ayes in the Kianjavato Classified Forest, a disturbed forest in south-eastern Madagascar, from October 2013 to October 2014. We used radiotelemetry and focal-animal sampling methods to collect behavioural data. We recorded GPS coordinates of the focal animal every 20 min, calculating the home range size for each individual. Results showed that male aye-ayes spent most of their time feeding and travelling. Their feeding time primarily focussed on larvae and adult insects from various substrates, and to a lesser extent Canarium spp. seeds. Home range sizes of the 2 males varied between individuals, overlapped greatly, and appeared to be related to the location of females. Our findings indicate that aye-aye behaviours are strongly indicative of insect-centric feeding ecology.

Comparing the use of live trees and deadwood for larval foraging by aye-ayes (Daubentonia madagascariensis) at Kianjavato and Torotorofotsy, Madagascar.

Aye-aye (Daubentonia madagascariensis) feeding behavior has become synonymous with deadwood foraging. However, deadwood is not always the most frequently used substrate, as some aye-ayes use live trees more often to access invertebrates. We sought to compare the frequency of aye-aye invertebrate foraging in deadwood and live trees to better understand their feeding behaviors. We followed two male aye-ayes at Kianjavato, a heavily disturbed habitat in southeastern Madagascar, from October 2013 to October 2014, and one male and one female aye-aye at Torotorofotsy, a continuous forest in eastern Madagascar, from July 2014 to December 2015. We collected feeding data by recording the behavior of a focal aye-aye every 5 min for a total of 373 h at Kianjavato and 383 h at Torotorofotsy. Our results showed no difference in the amount of deadwood used between the individuals. However, there was a significant difference in the amount of live tree feeding between the female at Torotorofotsy and one of the males at Kianjavato. We conclude that feeding on invertebrates in live trees is more important to aye-ayes than previously realized and that aye-ayes are exceedingly flexible in their invertebrate feeding behaviors, adjusting to their habitat by using various substrates.

Aye-aye (Daubentonia madagascariensis) feeding strategies at Ranomafana National Park, Madagascar: an indirect sampling method.

In this research, we focused on aye-aye populations in Ranomafana National Park, Madagascar. From August to December 2008, we tested how aye-aye feeding was influenced by presence/absence of both fruiting and non-fruiting Canarium trees. Deadwood feeding traces were used as a proxy for evidence of Canarium feeding. We enumerated deadwood feeding traces in 20 locations, 10 with Canarium, 10 without. Each location contained two transects (80 m L × 20 m W) for a total area of 5.6 ha. Feeding trace results for Canarium locations compared to non-Canarium locations were not significant (Z = -1.926, p = 0.083); however, feeding trace results were significant when comparing fruiting and non-fruiting Canarium locations (Z = -2.417, p = 0.016). These results highlight the importance of Canarium in the diet of aye-ayes and demonstrate how the distribution of this resource may influence the foraging behavior of aye-ayes.