The effect of vitamin D deficiency on the fertility and reproductive capacity of male rats was investigated. Male weanling rats were fed vitamin D-deficient or vitamin D-replete diets until maturity, and mated to age-matched, vitamin D-replete females. Vitamin D-deficient males were capable of reproduction. However, successful matings, i.e., presence of sperm in the vaginal tract of the female, by vitamin D-deficient males were reduced by 45% when compared to matings by vitamin D-replete males. Fertility (successful pregnancies in sperm-positive females) was reduced by 73% in litters from vitamin D-deficient male inseminations when compared to litters from females inseminated by vitamin D-replete males. These results demonstrate that vitamin D and its metabolites are necessary for normal reproductive functions in the male rat.

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Studies of bone from summer-active little brown bats, Myotis lucifugus lucifugus, have demonstrated sex differences in the renewal of skeletal mineral reserves following spring-arousal from hibernation. Patterns of bone remodeling in both sexes of bats indicate that new bone formation does not occur during hibernation: All new bone formation occurs during the summer-active season. Results show that a short period of time elapses after hibernation before the initial demands of a large fetus and rapidly growing neonate are expressed on maternal skeletal reserves. Bone loss in summer-active females was associated with pregnancy and lactation, whereas summer-active males did not show evidence of bone loss but, instead, uninterrupted bone accretion throughout the summer-active season. Osteoclasts and bone-forming osteoblasts, absent during the hibernation period, reappeared on bone surfaces following spring-arousal from hibernation. There was no apparent increase in osteoclast numbers or activity during lactation but resorption cavities were found in deep cortical lamellae distant from bone surfaces. The increase in bone resorption in lactating bats appeared to be by osteocytic osteolysis, suggesting that it might be a significant mechanism of bone/calcium regulation in this hibernating mammal throughout the year.

We performed experiments to determine whether treatment with vitamin D or 1,25-dihydroxycholecalciferol could reverse male infertility caused by vitamin D deficiency. Additionally, an attempt was made to distinguish between a direct and an indirect effect of 1,25-dihydroxycholecalciferol on reproductive tissue. Vitamin D-deficient male rats with impaired fertility were treated with vitamin D and 1,25-dihydroxycholecalciferol for 3 wk, then mated. Secondly, vitamin D-deficient male rats were made normocalcemic by increasing dietary calcium, and their fertility was compared with that of vitamin D-deficient, hypocalcemic rats. The fertility of male rats was restored by treatment with either vitamin D or 1,25-dihydroxycholecalciferol. However, fertility was also restored in vitamin D-deficient animals by feeding them a diet supplemented with high levels of calcium. These results indicate that the influence of vitamin D and its active metabolite, 1,25-dihydroxycholecalciferol, on male fertility is indirect. Vitamin D and 1,25-dihydroxycholecalciferol seemed to influence male fertility by acting on classic target tissues and regulating levels of calcium in reproductive tissues.

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a b s t r a c tWe describe and formally name a species of big-eared bat (genus: Micronycteris), collected from the Lesser Antillean island of Saint Vincent. The new species is distinguished from its closest relative, Micronycteris megalotis, by its large size, distinct craniodental features, and by mitochondrial DNA variation. The distribution of the new species is restricted to the island of St. Vincent, southern Lesser Antilles. Relaxed molecular clock analyses indicate the most recent common ancestor between the St. Vincent species of Micronycteris and mainland populations of M. megalotis is less than 1 million years. Rising sea levels during the late Pleistocene likely contributed to the geographic isolation and subsequent allopatric speciation of this new species. Our data reinforce previous hypotheses regarding unrecognized species diversity within the M. megalotis complex.

a b s t r a c t Currently, four species of Myotis are known from the islands of the Caribbean (Myotis dominicensis, M. martiniquensis, M. nesopolus, and M. nigricans). Myotis dominicensis and M. martiniquensis are endemic to the Lesser Antilles, whereas M. nesopolus and M. nigricans are considered conspecific with mainland populations. Recent phylogenetic and phylogeographic studies provided hypotheses regarding the origin and diversification of M. dominicensis and M. martiniquensis.However, these studies focused primarily on convergent morphology or distribution patterns of this genus and not on the evolutionary history of Caribbean Myotis. Here, we explore variation across multiple datasets generated from Caribbean Myotis. We present morphologic and genetic (mitochondrial and nuclear) data from an extensive sample of Caribbean Myotis species, including the previously unsampled taxa M. martiniquensis nyctor and M. nesopolus. Our data indicate that the historically recognized subspecies M. m. nyctor is genetically and morphologically distinct from M. martiniquensis, warranting recognition of a third Caribbean endemic-Myotis nyctor. Moreover, we provide evidence of unrecognized species-level variation in Caribbean and northern South American populations of Myotis.

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