Reproductive patterns in pygmy lorises (Nycticebus pygmaeus): Behavioral and physiological correlates of gonadal activity

Bioacoustics as a tool to monitor the estrus cycle in a female slow loris (Nycticebus sp.)

Evidence-based husbandry leading to increased reproductive success and strengthening of ex situ populations of slow lorises (Nycticebus spp.) living in zoos is highly important. Better fulfillment of their social needs is one of the main priorities in achieving these objectives. We performed 21-month long acoustic monitoring of a zoo-kept female slow loris (Nycticebus sp.) housed either singly or with one of two males to examine whether her estrus cycle potentially could be detected based on her vocal activity. We found a regular cycle of remarkably increased whistle production that lasted approximately 31.2 days in a nocturnal exhibit and approximately 39 days in an off-show room. The regular cycle of increased vocal activity corresponded to a previously described estrus cycle of slow lorises and was observable in the presence of both males as well as when the female was housed singly. Additionally, vaginal smears collected from the female close to the peak period of her vocal activity showed signs of proestrus and estrus. The acoustic properties of the whistles, specifically that they did not overlap with or were loud enough to exceed background noise commonly occurring in zoos, made them perfect candidates for analyses involving automatic processing of a large number of recordings. We conclude that bioacoustics represents a promising, completely noninvasive and relatively easily applicable tool that allows detection and anticipation of the estrus cycle in some females, thus improving the social management of slow lorises living in zoos.

Assessment of the reproductive physiology of the potto (Perodicticus potto) through fecal hormone metabolite analyses and trans-abdominal ultrasonography

Potto (Perodicticus potto) reproductive biology has been minimally studied. Noninvasive endocrinology and ultrasonography are proven tools for reproductive assessment in other primates. In this study, we used fecal hormone metabolite analysis to monitor one adult male potto and four females at different life stages. Validated testosterone (T), estrone conjugate (EC), and progesterone (P4) enzyme immunoassays (EIA) were used to assess male testicular function and female ovarian and placental activity. The male excreted mean T concentrations of 4.72 (±1.66) μg/g feces, that did not differ (P > 0.05) over time or when paired with alternate females. Baseline concentrations of EC (range: 47.93-78.81 ng/g feces) and P4 (range: 2.29-12.46 μg/g feces) differed among adult females. Follicular phases averaged 9.1 days (±3.43, n = 30 phases), whereas luteal phases averaged 19.89 days (±9.49, n = 19 phases). Gestation length (n = 2 pregnancies) was 170 days. Gestational EC and P4 concentrations were positively correlated (pregnancy A, r (132) = 0.71; pregnancy B, r (145) = 0.76) and returned to non-pregnant luteal phase levels 3-7 days post parturition. Extreme differences between pregnant and non-pregnant EC and P4 concentrations may allow for one-sample pregnancy diagnosis. Trans-abdominal ultrasonography was validated for pregnancy diagnosis with the fetus observed between 100 and 110 days post breeding. To our knowledge, this is the first use of fecal endocrinology and ultrasonography to monitor reproductive function and pregnancy in this species, and the only study in any lorisid to measure progestagens in correlation with reproductive events.

Different ontogenetic patterns of testosterone production reflect divergent male reproductive strategies in chimpanzees and bonobos

Male reproductive effort is often strongly related to levels of the steroid hormone testosterone. However, little research has examined whether levels of testosterone throughout development might be tied to individual or species differences in the reproductive strategies pursued by adult males. Here, we tested the hypothesis that inter-specific differences in male reproductive strategy are associated with differences in the pattern of testosterone production throughout early life and puberty. We compared testosterone levels from infancy to adulthood in two closely related species where levels of mating competition and male-male aggression differ significantly, bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). We predicted that the reduction in male mating competition found in bonobos would be accompanied by a lesser developmental increase in testosterone production. We performed radioimmunoassay of salivary testosterone levels in a mixed-longitudinal sample of both species, collected from individuals living in semi free-ranging populations. This allowed us to examine the effects of development in a more naturalistic setting than possible in a zoo or laboratory. We found that among chimpanzees, testosterone levels declined slightly from infancy to juvenility, then remained low until increasing markedly during adolescence (with pubertal increases most pronounced among males). In contrast, there was little change in testosterone production with age in bonobos of either sex, with levels of testosterone consistent throughout infancy, juvenility, and the transition to adulthood. Our data are therefore consistent with the hypothesis that the ontogenetic pattern of testosterone production can be subject to rapid evolutionary change, shifting in association with species differences in male reproductive strategy.

A survey of husbandry practices for lorisid primates in North American zoos and related facilities

Zoos and related facilities in North America currently manage five species in the primate family Lorisidae: the greater (Nycticebus coucang), Bengal (N. bengalensis) and pygmy (N. pygmaeus) slow lorises, red slender loris (Loris tardigradus), and potto (Perodicticus potto). We used an online survey to describe institutional housing and husbandry practices for these species and assess the extent to which practices are consistent with established guidelines. Our results show that most captive lorisids are housed solitarily or in pairs. Most individuals occupy a single exhibit space in a building dedicated to nocturnal animals. Facilities are commonly meeting recommendations for abiotic exhibit design and are providing animals with an enriched environment. However, pottos and slender lorises currently occupy exhibit spaces smaller than the recommended minimum, and the impact of cleaning protocols on olfactory communication should be critically evaluated. Few facilities are taking advantage of the benefits of positive reinforcement training for promoting animal welfare. Research is greatly needed on the effects of exhibit lighting on behavior, health, and reproduction; and to determine how best to manage the social needs of lorisids with naturally dispersed social structures. Although captive populations of slender lorises, pottos, and slow lorises are declining, we suggest that improved husbandry knowledge has the potential to positively influence population sustainability and to enhance future efforts to manage the growing pygmy loris population.

Eye size at birth in prosimian primates: life history correlates and growth patterns

Background

Primates have large eyes relative to head size, which profoundly influence the ontogenetic emergence of facial form. However, growth of the primate eye is only understood in a narrow taxonomic perspective, with information biased toward anthropoids.

Methodology/Principal Findings

We measured eye and bony orbit size in perinatal prosimian primates (17 strepsirrhine taxa and Tarsius syrichta) to infer the extent of prenatal as compared to postnatal eye growth. In addition, multiple linear regression was used to detect relationships of relative eye and orbit diameter to life history variables. ANOVA was used to determine if eye size differed according to activity pattern. In most of the species, eye diameter at birth measures more than half of that for adults. Two exceptions include Nycticebus and Tarsius, in which more than half of eye diameter growth occurs postnatally. Ratios of neonate/adult eye and orbit diameters indicate prenatal growth of the eye is actually more rapid than that of the orbit. For example, mean neonatal transverse eye diameter is 57.5% of the adult value (excluding Nycticebus and Tarsius), compared to 50.8% for orbital diameter. If Nycticebus is excluded, relative gestation age has a significant positive correlation with relative eye diameter in strepsirrhines, explaining 59% of the variance in relative transverse eye diameter. No significant differences were found among species with different activity patterns.

Conclusions/Significance

The primate developmental strategy of relatively long gestations is probably tied to an extended period of neural development, and this principle appears to apply to eye growth as well. Our findings indicate that growth rates of the eye and bony orbit are disassociated, with eyes growing faster prenatally, and the growth rate of the bony orbit exceeding that of the eyes after birth. Some well-documented patterns of orbital morphology in adult primates, such as the enlarged orbits of nocturnal species, mainly emerge during postnatal development.

The reproductive endocrinology and behavior of Vancouver Island marmot (Marmota vancouverensis)

The Vancouver Island marmot (Marmota vancouverensis; VIM) is one of North America's most endangered species with fewer than 150 individuals remaining in the wild. A captive breeding program was established across four facilities in Canada as an insurance population and source of animals for reintroduction to the wild. The purpose of this study was to gather information about the basic reproductive biology and behavior of this species, which is essential to improve captive breeding programs. Regular fecal samples were obtained from adult female (n = 14) and male (n = 10) marmots, 2 years of age and older, over 1-3 breeding seasons (2-3 months duration posthibernation) for steroid hormone analysis. Enzyme immunoassays were validated for quantifying fecal testosterone metabolite concentrations for males, and fecal estrogen and progesterone metabolite concentrations for females. Results indicated that fecal progesterone metabolite concentrations can be used to monitor ovulation and pregnancy. Behavioral monitoring through infrared video surveillance was conducted in four breeding pairs over a 2-year period (n = 7 behavioral profiles). Breeding behaviors correlated strongly with changes in reproductive endocrine profiles. A high frequency of play behavior or "wrestling" was observed in conjunction with breeding activity before an elevation in progesterone metabolite concentrations. Impending parturition was associated with increased aggression and exclusion of the male from the maternal nestbox as well as an increase in nesting activity. Observational data combined with hormonal analysis suggest that female VIMs are induced ovulators and that multiple breeding attempts may be required for ovulation and conception. Gestation appears to be approximately 34 days from peak breeding activity (32 days from estimated ovulation). Fecal testosterone concentrations suggest that testicular activity is seasonal with the reproductive activity occurring immediately posthibernation. Monitoring breeding behavior is a useful means of indicating estrus, conception and pregnancy, which can also be supported by the hormonal analysis of daily fecal samples of individual animals.

Field surveys of the Vulnerable pygmy slow loris Nycticebus pygmaeus using local knowledge in Mondulkiri Province, Cambodia

The pygmy slow loris Nycticebus pygmaeus is a little-studied primate endemic to Vietnam, Laos, southern China and eastern Cambodia. Our study aimed to gain local knowledge on the distribution and ecology of, and threats to, the species by interviewing hunters, traders and wildlife protection staff, and to verify this information using a spotlighting survey in three major reserves in Mondulkiri Province, Cambodia. Encounter rates of pygmy loris were assessed along 29 transects (129.5 km), yielding observations of 26 individuals. Mean encounter rates were 0.40 km-1 in Seima Protection Forest, 0.10 km-1 in Phnom Prich Wildlife Sanctuary and 0.00 km-1 in Mondulkiri Protected Forest. Informants had knowledge of where populations occurred, their diet, sociality and habitat preferences. Widespread large population declines were reported and informants linked this to high hunting pressure, particularly in 2001 and 2002. In late 2008 and 2009 we resurveyed three transects that had high encounter rates in early 2008 and failed to detect any lorises. Local informants reported high hunting pressure during the previous wet season in two of these sites, and a gold mine development was underway in the third site. Urgent actions are required to address these population declines and to assess the conservation status of pygmy lorises throughout eastern Cambodia.

Phylogenetic analysis of the fecal flora of the wild pygmy loris

The bacterial diversity in fecal samples from the wild pygmy loris was examined with a 16S rDNA clone library and restriction fragment length polymorphism analysis. The clones were classified as Firmicutes (43.1%), Proteobacteria (34.5%), Actinobacteria (5.2%), and Bacteroidetes (17.2%). The 58 different kinds of 16S rDNA sequences were classified into 16 genera and 20 uncultured bacteria. According to phylogenetic analysis, the major genera within the Proteobacteria was Pseudomonas, comprising 13.79% of the analyzed clone sequences. Many of the isolated rDNA sequences did not correspond to known microorganisms, but had high homology to uncultured clones found in human feces.