A 24-Year Record of Female Reproductive Dynamics in Two Sympatric Mouse Lemur Species in Northwestern Madagascar

Abstract

Seasonal reproduction is widespread among primates but the degree of reproductive synchrony and plasticity can vary, even between closely related species. This study compares the dynamics of female reproductive seasonality in two mouse lemur species, Microcebus murinus and M. ravelobensis, in Ankarafantsika National Park, Madagascar, across 24 years. We collected 4321 records of female reproductive state from 1033 individual females (319 M. murinus, 714 M. ravelobensis). The analyses revealed disparate reproductive schedules: While female M. murinus showed high degrees of reproductive synchrony throughout all years, leading to the production of two successive litters, the seasonal onset of estrus (= reproductive activation) in female M. ravelobensis was more flexible than in M. murinus, starting 2-4 weeks earlier, varying by up to 4 weeks between years, and being less synchronized. M. ravelobensis females became reproductively active later in years with more rainfall, in particular rain in February, but the timing of reproductive activation was not related to differences in temperatures. The likelihood of early conception was significantly lower in M. ravelobensis than in M. murinus. This was partly due to delayed reproductive activation in young animals, and a lower likelihood of early conception for females with low body mass in M. ravelobensis. Our results suggest high, adaptive reproductive plasticity in M. ravelobensis that may enable individuals to respond flexibly to yearly environmental changes and expand the reproductive period under favorable conditions. These species differences in reproductive schedules may be the result of the divergent evolutionary histories of the two mouse lemur species in different parts of Madagascar.

RETRACTED: RADseq Data Suggest Occasional Hybridization between Microcebus murinus and M. ravelobensis in Northwestern Madagascar

“…Similarly, the present study finds evidence that effective prezygotic mechanisms of reproductive isolation are largely in place for M. murinus and the more distantly related M. ravelobensis, though results also demonstrate that interspecific mating between mouse lemur species must occur occasionally, leading to the production of fertile offspring. The rarity of such events is not surprising, as it has already been shown that both species differ in habitat preferences [49,71,72], reproductive schedules [73][74][75], and advertisement calls [76], and can discriminate conspecifics based on olfactory signals [77,78]. Further studies are needed to clarify whether M. murinus also hybridizes with its congeners M. berthae, M. myoxinus and M. bongolavensis at other localities in order to identify under which circumstances reproductive isolation breaks down in mouse lemurs.…”

“…In addition, only M. murinus males (n = 7) were captured at this location during our field season in 2017, suggesting that these microhabitats may not to be favorable for female M. murinus. The temporarily limited availability of conspecific mates during some years and in some places, possibility aggravated by the very short mating season and brief receptive periods characteristic of female mouse lemurs [73,74], may thus lead to accidental hybridization. Given ongoing habitat loss and fragmentation in western Madagascar, such scenarios may become more likely in the future and should add to existing conservation concerns.…”

Host‐related and environmental factors influence long‐term ectoparasite infestation dynamics of mouse lemurs in northwestern Madagascar

“…As M. murinus was not found in JBB across all years and months, the variable combining sampling site and host species was necessary to avoid modeling errors. Juvenile age was deduced from a low initial body mass (clearly below average) and its steady increase over the first months of capture (Radespiel et al, 2021). To control for pseudoreplication based on multiple sampling of single hosts, host identity ("animal ID") was added as a random factor.…”

“…M. murinus and M. ravelobensis live in partial sympatry (i.e., occurring together in some forests but alone in others) in the two study sites, exhibit similar body sizes (ca. 60 g), overlapping diets and seasonal reproductive activity (Radespiel et al, 2021; Thorén et al, 2011; Zimmermann et al, 1998). According to previous studies (Kiene et al, 2020; Klein et al, 2018), seasonality, habitat fragmentation, host sex, body mass, and species seem to be important determinants of host ectoparasite infestations.…”

“…These sites differ largely in forest structure, forest composition, soil type, and proximity to surface water and, therefore, can be considered different habitats (Chanu et al, 2012;Rendigs et al, 2003;Sehen et al, 2010). Both host species have been studied in a long-term project focusing on their socioecology and population dynamics (Chanu et al, 2012;Henkel et al, 2019Henkel et al, /2020Radespiel et al, 1998Radespiel et al, , 2003Radespiel et al, , 2021Rakotondravony & Radespiel, 2009;Rendigs et al, 2003;Thorén et al, 2011). M. murinus and M. ravelobensis live in partial sympatry (i.e., occurring together in some forests but alone in others) in the two study sites, exhibit similar body sizes (ca.…”