Gray-brown Mouse Lemurs (Microcebus griseorufus) as an Example of Distributional Constraints through Increasing Desertification

Lepilemur petteri latrine placement in Tsimanampetsotse National Park, Madagascar

Latrine behaviour in lemurs has been interpreted as a means of olfactory communication linked to energy efficient resource defence against neighbouring individuals and/or social bonding within social groups. For social bonding, latrines might best be placed at the core of home ranges, while resource defence could be based on defending the most important part of the home range, i.e., the core area or by establishing olfactory landmarks at the periphery of the home range. Most studies on lemurs describe deposition of urine and faeces in latrines in the core of the home range. In a study at the limit of the distributional range of Lepilemur petteri, at a site with unpredictable weather conditions, we radio-tracked 12 individuals and located latrines within their home ranges. In our study, latrines were located at the periphery of the home ranges. This is interpreted as a means to defend a larger area rather than specific resource rich sites that may or may not provide food in a given year. Regardless of the flexible spatial pattern, and in common with other mammals, lemur latrines are characterized by conspicuous trees, even though urine and faeces are deposited at the base of trees. This indicates some kind of optimal structure of latrines to convey information most effectively, possibly by combining visual and olfactory cues.

Anthropogenic Disturbance Impacts Gut Microbiome Homeostasis in a Malagasy Primate

Increasing anthropogenic disturbances in Madagascar are exerting constrains on endemic Malagasy lemurs and their habitats, with possible effects on their health and survival. An important component of health is the gut microbiome, which might be disrupted by various stressors associated with environmental change. We have studied the gut microbiome of gray-brown mouse lemurs (Microcebus griseorufus), one of the smallest Malagasy primates and an important model of the convergent evolution of diseases. We sampled two sites: one situated in a national park and the other consisting of a more disturbed site around human settlement. We found that more intense anthropogenic disturbances indeed disrupted the gut microbiome of this lemur species marked by a reduction in bacterial diversity and a shift in microbial community composition. Interestingly, we noted a decrease in beneficial bacteria (i.e., members of the Bacteroidaceae family) together with a slight increase in disease-associated bacteria (i.e., members of the Veillonellaceae family), and alterations in microbial metabolic functions. Because of the crucial services provided by the microbiome to pathogen resistance and host health, such negative alterations in the gut microbiome of mouse lemurs inhabiting anthropogenically disturbed habitats might render them susceptible to diseases and ultimately affecting their survival in the shrinking biodiversity seen in Madagascar. Gut microbiome analyses might thus serve as an early warning signal for pending threats to lemur populations.

Living in tiny fragments: a glimpse at the ecology of Goodman's mouse lemurs (Microcebus lehilahytsara) in the relic forest of Ankafobe, Central Highlands, Madagascar

Habitat fragmentation is one of the major types of anthropogenic change, though fragmented landscapes predate human intervention. At present, the Central Highlands of Madagascar are covered by extensive grasslands interspersed with small discrete forest patches of unknown antiquity. Ankafobe, an actively protected site, comprises two such fragments of 12 and 30 ha, respectively, known to harbor three lemur species and other endemic wildlife. At this location, we conducted a survey of resident Goodman's mouse lemurs, Microcebus lehilahytsara, to determine baseline behavioral and ecological conditions for this isolated population. By studying primates in forest fragments, investigators can characterize the effects of shrinking habitats and decreasing connectivity on species diversity and survival, thus providing a glimpse into the potential resilience of species in the face of anthropogenic disturbance. Investigating the behavioral ecology of Goodman's mouse lemurs across their geographic range could help us understand their metabolic and ecological flexibility and predict species long-term survival prospects. We conducted night transect walks, using capture techniques and telemetry, to track eight radio-collared individuals. Preliminary density estimates based on a limited number of sightings (n = 18) were 2.19 ind/ha, and home range assessments ranged between 0.22 and 3.67 ha. Mouse lemurs traveled an average of 425 m nightly during the 5-h tracking periods and primarily fed on fruits of the mistletoe Bakerella clavata. The finding that Goodman's mouse lemurs apparently thrive in the seasonally cold and arid forest fragments in the Central Highlands indicates that they may be among the most tolerant and adaptable lemur species in Madagascar. These results point towards an exciting research program that focuses on ecological tolerance as a mechanism for long-term species survival.

Lemur paparazzi: Arboreal camera trapping and occupancy modeling as conservation tools for monitoring threatened lemur species

Primate species face growing risks of extinction throughout the world. To better protect their populations, effective monitoring techniques are needed. The goal of this study was to evaluate the use of arboreal camera traps and occupancy modeling as conservation tools for threatened lemur species. This project aimed to (1) estimate the occupancy and detection probabilities of lemur species, (2) investigate factors potentially affecting lemur habitat use, and (3) determine whether ground or arboreal cameras are better for surveying lemur assemblages. We conducted camera trapping research in five forest fragments (total trap nights = 1770; 900 arboreal trap nights (134 photo events); 870 ground trap nights (2 photo events)) and reforestation areas (total trap nights = 608; 1 photo event) in Kianjavato, Madagascar from May to September 2019. We used arboreal trap data from fragments to estimate occupancy for five species: the red-fronted brown lemur (Eulemur rufifrons; ψ = 0.54 ± SD 0.03), Jolly's mouse lemur (Microcebus jollyae; ψ = 0.14 ± 0.17), the greater dwarf lemur (Cheirogaleus major; ψ = 0.42 ± 0.30), the red-bellied lemur (Eulemur rubriventer; ψ = 0.24 ± 0.03), and the black-and-white ruffed lemur (Varecia variegata; ψ = 0.24 ± 0.08). Tree diameter, elevation, distance to village, and canopy connectivity were important predictors of occupancy, while camera height, canopy connectivity, fragment ID, and fragment size predicted detection. Arboreal cameras recorded significantly higher species richness compared with ground cameras. We suggest expanded application of arboreal camera traps in future research, but we recommend longer trapping periods to better sample rarer species. Overall, arboreal camera trapping combined with occupancy modeling can be a highly efficient and useful approach for monitoring and predicting the occurrence of elusive lemur species and has the potential to be effective for other arboreal primates and canopy taxa across the globe.

Adenovirus infection is associated with altered gut microbial communities in a non-human primate

Adenovirus (AdV) infections are one of the main causes of diarrhea in young children. Enteric AdVs probably disrupt gut microbial defences, which can result in diarrhea. To understand the role of the gut microbiome in AdV-induced pathologies, we investigated the gut microbiome of a naturally AdV-infected non-human primate species, the Malagasy mouse lemur (Microcebus griseorufus), which represents an important model in understanding the evolution of diseases. We observed that AdV infection is associated with disruption of the gut microbial community composition. In AdV+ lemurs, several commensal taxa essential for a healthy gut microbiome decreased, whereas genera containing potential pathogens, such as Neisseria, increased in abundance. Microbial co-occurrence networks revealed a loss of important microbial community interactions in AdV+ lemurs and an overrepresentation of Prevotellaceae. The observation of enteric virus-associated loss of commensal bacteria and associated shifts towards pathobionts may represent the missing link for a better understanding of AdV-induced effects in humans, and also for their potential as drivers of co-infections, an area of research that has been largely neglected so far.

Ectoparasites of endemic and domestic animals in southwest Madagascar

Human encroachment of natural habitats bears the threat of disease transmission between native and introduced species that had not come into contact before, thus promoting the spread of new diseases in both directions. This is a matter of concern especially in areas where human-wildlife contact has not been intense in the recent past. In southwest Madagascar, we collected ectoparasites from various mammalian hosts and chicken, and examined their host preferences and their prevalence in relation to season and habitat degradation. Field-work took place in the northern portion of Tsimanampetsotsa National Park and the adjacent coastal strip (littoral) in the dry and in the rainy season of 2016/2017. Endemic mammals were trapped with live traps placed in habitats of different degrees of degradation: 1) relatively pristine forest, 2) degraded forest, 3) cultivated and shrub land. Rats and mice were also trapped in 4) villages. We identified 17 species of ectoparasites (296 individuals of ticks [5 species], 535 lice [7 spp.], 389 fleas [4 spp.] and 13 mites [1 sp.]) collected from 15 host species. There was no indication for seasonal or habitat effects on parasite infection. A large portion of the parasites was host-specific. Some ectoparasite species were shared either by several endemic or by several introduced species, but apart from the introduced flea species Echidnophaga gallinacea (collected from six different hosts including the endemic carnivore Galidictis grandidieri) no other ectoparasite species was shared between endemic and introduced host species.

Maintaining microendemic primate species along an environmental gradient - parasites as drivers for species differentiation

Understanding the drivers of species adaptations to changing environments on the one hand and the limits for hybridization on the other hand is among the hottest questions in evolutionary biology. Parasites represent one of the major selective forces driving host evolution and at least those with free-living stages are at the same time dependent on the ecological conditions of their host's habitat. Local immunological adaptations of host species to varying parasite pressure are therefore expected and might represent the genetic basis for ecological speciation and the maintenance of recently diverged species. Madagascar provides one of the rare examples where two partially sympatric primate species (Microcebus griseorufus, M. murinus) and their hybrids, as well as an allopatric species (M. cf rufus) live in close proximity along a very steep environmental gradient ranging from southern dry spiny bush to gallery forest to evergreen eastern humid rain forest, thus mimicking the situation encountered during extensions and retreats of vegetation formations under changing climatic conditions. This system was used to study parasite infection and immune gene (MHC) adaptations to varying parasite pressure that might provide selective advantages to pure species over hybrids. Parasite burdens increased with increasing humidity. M. griseorufus, M. murinus, and their hybrids but not M. rufus shared the same MHC alleles, indicating either retention of ancestral polymorphism or recent gene flow. The hybrids had much higher prevalence of intestinal parasites than either of the parent species living under identical environmental conditions. The different representation of parasites can indicate a handicap for hybrids that maintains species identities.

Effects of clear-fell harvest on bat home range

We investigated effects of roost loss due to clear-fell harvest on bat home range. The study took place in plantation forest, inhabited by the New Zealand long-tailed bat (Chalinolobus tuberculatus), in which trees are harvested between the ages 26-32 years. We determined home ranges by radiotracking different bats in areas that had and had not been recently clear-fell harvested. Home ranges were smaller in areas that had been harvested. Adult male bats selected 20-25 year old stands within home ranges before and after harvest. Males selected edges with open unplanted areas when harvest had not occurred but no longer selected these at proportions greater than their availability post harvest, probably because they were then readily available. This is the first radiotracking study to demonstrate a change in home range size and selection concomitant with felling of large areas of plantation forest, and thus quantify negative effects of forestry operations on this speciose group. The use of smaller home ranges post-harvest may reflect smaller colony sizes and lower roost availability, both of which may increase isolation of colonies and vulnerability to local extinction.