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Bats emerge from their day roost after dusk and different factors can affect the timing of departure, return, and duration of nocturnal activities. This study provides information on the time of emergence and return of an endemic Malagasy fruit bat, Rousettus madagascariensis, in a cave located in the Réserve Spéciale d’Ankarana, northern Madagascar. Individuals were captured in a narrow passage between the roost and cave exit and capture time for each individual was noted. Variation according to sex, age, and body condition, as well as the influence of season, and the sunset and sunrise time were analyzed. During the dry season, individuals started to emerge at 1913 hours and returned to the cave generally by 0505 hours; the duration of time outside the cave during the dry season was higher in adult females (0952 hours) followed by subadult males (0937 hours), sub-adult females (0931 hours), and adult males (0910 hours). During the wet season, individuals exited at 1926 hours and returned at 0351 hours; as in the dry season, adult females spent more time outside the cave (0833 hours), than sub-adult females (0800 hours), and adult males (0752 hours). The period of emergence varied according to the age and sex classes, and time of predawn return associated with the previous nocturnal activity. The period of return was influenced by season, and age and sex classes. Such information is useful to quantify shifts in bat ecology, especially for endemic species with limited distribution or those playing an important role in ecosystem services.

We studied variation in the Body Condition Index (BCI) of a Malagasy frugivorous bat, Rousettus madagascariensis (Pteropodidae), in relation to the abundance of ectoparasite flies, Eucampsipoda madagascarensis (Nycteribiidae). The study site was a cave in northern Madagascar that was visited three times during the dry season (September 2014, 2015, and 2016) and two times during the wet season (January 2015 and 2016). Two measurements were taken from all captured Rousettus to evaluate their BCI: forearm length and body mass. In total, we sampled ectoparasites from 1,030 R. madagascariensis during the five visits. The BCI of sampled bats showed statistical differences when compared by season and segregated by different age and sex classes, with generally the higher mean values during the wet season and lower values during the dry season. In most cases, the abundance of E. madagascarensis for each of the different bat age and sex classes did not differ between seasons. A weak positive relationship was found ...

On the basis of four visits to the Grotte des Chauves-souris (12°57′S, 49°07′E), Parc National d'Ankarana, northern Madagascar, we examine patterns of sexual dimorphism and seasonal differences in body mass of Rousettus madagascariensis, an endemic Malagasy Pteropodidae. Two visits per season were made over the course of two years, dry season (September 2014 and 2015) and rainy season (January 2015 and 2016). Individuals of this species were trapped when exiting the cave after dusk or entering before dawn. Animals were aged, sexed, and then individually marked before being released. In total, 271 adult males and 289 adult females were captured. Although some overlap was found in measurement ranges, males showed significantly larger mean forearm length and body mass than females, including separate analyses of the four different capture periods and in the combined season dataset. For the September 2015 visit, for which a considerable number of adults of both sexes were captured at dusk and dawn, animals en...

International audience; Bats are reservoirs for emerging human pathogens, including Hendra and Nipah henipaviruses and Ebola and Marburg filoviruses. These viruses demonstrate predictable patterns in seasonality and age structure across multiple systems; previous work suggests that they may circulate in Madagascar's endemic fruit bats, which are widely consumed as human food. We aimed to (a) document the extent of henipa- and filovirus exposure among Malagasy fruit bats, (b) explore seasonality in seroprevalence and serostatus in these bat populations and (c) compare mechanistic hypotheses for possible transmission dynamics underlying these data. To this end, we amassed and analysed a unique dataset documenting longitudinal serological henipa- and filovirus dynamics in three Madagascar fruit bat species. We uncovered serological evidence of exposure to Hendra-/Nipah-related henipaviruses in Eidolon dupreanum, Pteropus rufus and Rousettus madagascariensis, to Cedar-related henipaviruses in E. dupreanum and R. madagascariensis and to Ebola-related filoviruses in P. rufus and R. madagascariensis. We demonstrated significant seasonality in population-level seroprevalence and individual serostatus for multiple viruses across these species, linked to the female reproductive calendar. An age-structured subset of the data highlighted evidence of waning maternal antibodies in neonates, increasing seroprevalence in young and decreasing seroprevalence late in life. Comparison of mechanistic epidemiological models fit to these data offered support for transmission hypotheses permitting waning antibodies but retained immunity in adult-age bats. Our findings suggest that bats may seasonally modulate mechanisms of pathogen control, with consequences for population-level transmission. Additionally, we narrow the field of candidate transmission hypotheses by which bats are presumed to host and transmit potentially zoonotic viruses globally.

Population size and survival are crucial factors to understand population dynamics of a given species, especially those that have long life spans and delayed sexual maturity, such as Pteropodidae bats. We studied the population size and apparent survival of individuals at a day roost site of an endemic cave-dwelling Malagasy fruit bat, Rousettus madagascariensis, in relation with age and sex. 1,801 individuals were captured and tagged over the course of four years in the Grotte des Chauves-souris, Reserve Speciale d'Ankarana, northern Madagascar. The Cormack-Jolly-Seber model and the POPAN model in the program MARK were used to analyze mark-recapture data and to estimate apparent individual survival and population size. The apparent survival of individuals ranged from 0.46 to 0.60, but exhibited significant variability associated with age, sex, and time. Apparent survival is lower in adults compared to sub-adults (Φadult = 0.49; Φsub-adult = 0.63). For adults, the apparent survival of males was higher (Φmale = 0.50; Φfemale = 0.47), and conversely for sub-adults, it was in favor of females (Φmale = 0.55; Φfemale = 0.70). Population size ranged from 1,245 (CI: 268–3,050) to 5,868 (CI: 3,520–10,601) and was significantly higher during the wet season as compared to the dry season. The survival rate in this population is strongly influenced by mortality and secondarily by dispersal. We found that the apparent survival of individuals has a positive impact on population growth but less than birth rate. Thus, the health and sustainability of the population relies heavily on individual survival.

This study examines seasonal behavioral activity in a cave day roost of an endemic Malagasy fruit bat, Rousettus madagascariensis (Chiroptera: Pteropodidae). Activities of both sexes (male and female) classified by age (neonate, sub-adult, and adult) were filmed in the cave using an infrared camcorder during the wet and dry seasons. Analyses of the videos were used to calculate the proportion of time spent conducting predefined behavior types during different 10 min periods. Measurements taken from captured individuals were employed to calculate the body condition index (BCI, ratio of body mass to forearm length) for the different age and sex classes. The results indicate that cave-roosting behavior changed as according to season. During the dry season, roosting individuals spent more time in ‘rest’and ‘consume ectoparasites’ behaviors and limited ‘move’ (flight and crawl) and ‘groom’ activities. Further, the BCI was lower during this period, as compared to the wet season, and this shift is presumably related to food availability or quality. During the wet season, ‘groom’ behavior frequency was higher and individuals formed a more dispersed roosting group configuration. The threshold for the shift to ‘tight’ group configuration and less grooming activity is correlated with climatological variables, specifically when the average temperature outside the cave was ≤ 25.3°C, the mean temperature inside the cave was ≤ 24.0°C, and the average relative humidity was ≤ 68.2%. In contrast, the presence of solitary roosting individuals and ‘loose’ group configuration were more common when the average temperature outside the cave was ≥ 27.1°C and the average temperature and relative humidity inside the cave was ≥ 25.0°C and ≥ 93.4%, respectively. Future studies should examine aspects of thermoregulation in cave-roosting pteropodids living in tropical areas, combined with measures of food availability and quality, and the relationship of these variables to reproduction.

We studied the diet, habitat use and biology of Rousettus madagascariensis, a relatively small (∼55–77 g) fruit bat endemic to Madagascar, between July 2004 and May 2005. Faecal analysis revealed few seeds in the diet, suggesting that the bats either feed extensively on nectar, flowers and leaves or on fruits with seeds too large to ingest. However, bats were captured near fruiting Ficus sp. inside relatively intact forest and Ficus sp. seeds were found in the faeces during March and April. Defecated Ficus rubra seeds germinated significantly faster than seeds from ripe fruits under controlled conditions, but germination rates were similar. Radio tracking and observations of light-tagged individuals revealed that R. madagascariensis travelled a straight line distance of at least 8 km between the roost and feeding locations, with round trip foraging routes of up to 27 km. Most juveniles were trapped between March and July and we infer that weaning of young started before 8 weeks of age. The features used to distinguish juveniles from adults were no longer evident in December and it appears therefore that R. madagascariensis reaches somatic maturity within a single year. Pregnancy, lactation and weaning in this species coincide with the austral summer when food availability is higher.

We used roost searches, mist netting and acoustic sampling to investigate the habitats used by bats in Parc National de Mantadia and the Reserve Speciale d'Analamazaotra, eastern Madagascar. Four species were caught in relatively intact humid forest (Myotis goudoti, Miniopterus manavi, Miniopterus majori and Emballonura atrata) two in agricultural land, Neoromicia matroka and Neoromicia melckorum, and one, Rousettus madagascariensis, in Eucalyptus plantations. Mormopterus jugularis, Chaerephon pumilus and Mops leucostigma were found roosting in buildings ca. three km from the humid forest. Acoustic sampling revealed that Neoromicia spp. and molossids were ubiquitous and were recorded from intact and degraded humid forest, Eucalyptus plantations and agricultural land. Myotis goudoti showed the strongest association with intact humid forest. Taxon richness, determined by acoustic sampling, was highest in humid forest but activity was highest in plantations and agricultural land. Mixed-habitat landscapes that surround protected forests and consist of a mosaic of regenerating forest, agriculture, wetlands, villages and plantations are important for bats and promote chiropteran diversity because they provide roosting and foraging sites for species that rarely use intact forest. The humid forests of eastern Madagascar have lower bat diversity than the island's western deciduous karst forests.

Goodman, Steven M., Griffiths, Owen (2006): A case of exceptionally high predation levels of Rousettus madagascariensis by Tyto alba (Aves: Tytonidae) in western Madagascar. Acta Chiropterologica 88 (2): 553-556, DOI: http://doi.org/10.5281/zenodo.3768733, {"references":["ANDREWS, P. 1990. Owls, caves and fossils. British Museum (Natural History), London, 231 pp.","GOODMAN, S. M., and O. LANGRAND. 1993. Food habits of the barn owl Tyto alba and the Madagascar long-eared owl Asio madagascariensis on Madagascar: adaptation to a changing environment. Pp. 147-154, in Proceedings of the 8th Pan- African Ornithological Congress (R. T. WILSON, ed.). Annales du Musee Royal de l'Afrique Centrale (Zoologie), 268 pp.","GOODMAN, S. M., and R. THORSTROM. 1998. The diet of the Madagascar red owl (Tyto soumagnei) on the Masoala Peninsula, Madagascar. Wilson Bulletin, 110: 417-421.","GOODMAN, S. M., O. LANGRAND, and C. J. RAXWORTHY. 1993a. Food habits of the Madagascar long-eared owl (Asio madagascariensis) in two habitats in southern Madagascar. Ostrich, 64: 79-85.","GOODMAN, S. M., O. LANGRAND, and C. J. RAXWORTHY. 1993b. The food habits of the barn owl (Tyto alba) at three sites on Madagascar. Ostrich, 64: 160-171.","GOODMAN, S. M., J. U. GANZHORN, and D. RAKOTON- DRAVONY. 2003. Introduction to the mammals. Pp. 1159-1186, in The natural history of Madagascar (S. M. GOODMAN and J. P. BENSTEAD, eds.). University of Chicago Press, Chicago, 1709 pp.","HAYSSEN, V., A. VAN TIENHOVEN, and A. VAN TIEN- HOVEN. 1993. Asdell's patterns of mammalian reproduction. Cornell University Press, Ithaca, 1023 pp.","MIDDLETON, G. 2004. Anjajavy-Narinda north karst, north-western Madagascar -- 2003. Journal of the Sydney Speleological Society, 48: 357-369.","RASOLOARISON, R., S. M. GOODMAN, and J. U. GANZ- HORN. 2000. Taxonomic revision of mouse lemurs (Microcebus) in the western portions of Madagascar. International Journal of Primatology, 21: 963-1019.","RAVOKATRA, M., L. WILME, and S. M. GOODMAN. 2003. Bird weights. Pp. 1059-1063, in The natural history of Madagascar (S. M. GOODMAN and J. P. BENSTEAD, eds.). University of Chicago Press, Chicago, 1709 pp."]}

Disturbance by tourists of bats in their day roosts represents a potential threat to the conservation of these mammals. We assessed the effect of experimental tourist visits on behavior of the Malagasy endemic Rousettus madagascariensis (Chiroptera: Pteropodidae) in the Ankarana National Park, northern Madagascar. We measured bat behavior, including time activity budgets, under two levels of experimental human visit proximity (far and near) and illumination (low and high). These visits caused an increase in bat flights and an increase in alertness in a frequently-visited colony with faint ambient daylight. The greatest response occurred for human approaches to 5–6 m that directly illuminated the bats and the least response occurred for approaches to 12–14 m that did not directly illuminate the bats. In an infrequently-visited colony with no ambient daylight, visits that remained 12–14 m away and did not illuminate the bats directly caused an increase in alert behavior and a decrease in bat grooming behavior. The difference in response between the colonies suggests that R. madagascariensis may demonstrate an attenuated response to some frequent human visits. Alternatively, colonies roosting with some ambient light may be less sensitive to disturbance from visits, and colonies with previous experience primarily with hunting visits may be more responsive to disturbance. Maintaining a minimum visit distance of 12 m and not illuminating the bats directly, as well as not opening other roost sites to tourism, is likely to help to limit disturbance of R. madagascariensis by tourists at Ankarana.