P-Mail: The Information Highway of Nocturnal, but Not Diurnal or Cathemeral, Strepsirrhines.

Scent marking is a well-established, but highly variable, mode of communication among strepsirrhine primates. We begin by reviewing this literature, focusing on nocturnal species. Our understanding about the information content of scent signals and the factors driving species diversity remains incomplete, owing to difficulties in acquiring comparative chemical data.

Shyer and larger bird species show more reduced fear of humans when living in urban environments.

As the natural habitats of many species are degraded or disappear, there is scope for these species to be established in urban habitats. To ease the establishment and maintenance of urban populations of more species we need to better understand what degree of phenotypical change to expect as different species transition into urban environments. During the first stages of urban colonization, behavioural changes such as an increase in boldness are particularly important.

A cost for high levels of sperm competition in rodents: increased sperm DNA fragmentation.

Sperm competition, a prevalent evolutionary process in which the spermatozoa of two or more males compete for the fertilization of the same ovum, leads to morphological and physiological adaptations, including increases in energetic metabolism that may serve to propel sperm faster but that may have negative effects on DNA integrity. Sperm DNA damage is associated with reduced rates of fertilization, embryo and fetal loss, offspring mortality, and mutations leading to genetic disease. We tested whether high levels of sperm competition affect sperm DNA integrity.

Beyond aggression: Androgen-receptor blockade modulates social interaction in wild meerkats.

In male vertebrates, androgens are inextricably linked to reproduction, social dominance, and aggression, often at the cost of paternal investment or prosociality. Testosterone is invoked to explain rank-related reproductive differences, but its role within a status class, particularly among subordinates, is underappreciated. Recent evidence, especially for monogamous and cooperatively breeding species, suggests broader androgenic mediation of adult social interaction.

Differences in the fatty-acid composition of rodent spermatozoa are associated to levels of sperm competition.

Sperm competition is a prevalent phenomenon that drives the evolution of sperm function. High levels of sperm competition lead to increased metabolism to fuel higher sperm velocities. This enhanced metabolism can result in oxidative damage (including lipid peroxidation) and damage to the membrane.

Metabolic rate limits the effect of sperm competition on mammalian spermatogenesis.

Sperm competition leads to increased sperm production in many taxa. This response may result from increases in testes size, changes in testicular architecture or changes in the kinetics of spermatogenesis, but the impact of each one of these processes on sperm production has not been studied in an integrated manner. Furthermore, such response may be limited in species with low mass-specific metabolic rate (MSMR), i.

A comparison of human chorionic gonadotropin and luteinizing hormone releasing hormone on the induction of spermiation and amplexus in the American toad (Anaxyrus americanus).

Background: Captive breeding programs for endangered amphibian species often utilize exogenous hormones for species that are difficult to breed. The purpose of our study was to compare the efficacy of two different hormones at various concentrations on sperm production, quantity and quality over time in order to optimize assisted breeding.

Methods: Male American toads (Anaxyrus americanus) were divided into three separate treatment groups, with animals in each group rotated through different concentrations of luteinizing hormone releasing hormone analog (LHRH; 0.

Asymmetric learning to avoid heterospecific males in Mesocricetus hamsters.

If a female mates with a male of a closely related species, her fitness is likely to decline. Consequently, females may develop behavioral mechanisms to avoid mating with heterospecific males. In some species, one such mechanism is for adult females to learn to discriminate against heterospecific males after exposure to such males.

Eulemur, me lemur: the evolution of scent-signal complexity in a primate clade.

Signal complexity has been linked to social complexity in vocal, but not chemical, communication. To address this gap, we examined the chemical complexity of male and female glandular secretions in eight species of Eulemur. In this diverse clade of macrosmatic primates, species differ by social or mating system and dominance structure.

Avoidance of interspecific mating in female Syrian hamsters is stronger toward familiar than toward unfamiliar heterospecific males.

Adult Syrian hamster females (Mesocricetus auratus) learn to discriminate against familiar heterospecific males (Turkish hamster, M. brandti). We investigated whether females learn to avoid any heterospecific male after exposure to just one heterospecific male.

Syrian hamster males below an age threshold do not elicit aggression from unfamiliar adult males.

In many species, young males are the dispersers, leaving their natal area after weaning to establish a breeding area of their own. As young males disperse, however, they are bound to encounter unfamiliar adult males with established territories. Such interactions between an adult male and a young male may always be agonistic.

Fluoxetine does not prevent interspecific mating between two hamster species.

In a recent study we showed that female Syrian hamsters (Mesocricetus auratus) from a laboratory stock readily mated with male Turkish hamsters (M. brandti). We hypothesized that captivity and/or unconscious selection of the most receptive females by researchers or animal caretakers results in heightened female sexual receptivity and reduces the tendency to reject heterospecific males.

Medial amygdala involvement in discrimination of same-species and closely-related-species male stimuli in estrous female Mesocricetus hamsters.

Efficient discrimination between individuals of closely related species is important to maximize reproductive potential. Some studies using males as subjects have indicated that the medial amygdala (MeA) is involved in discrimination between odors of conspecific females and females from distantly related species. The authors investigated the involvement of the MeA in discrimination by females between odors of conspecific males and odors of males of a closely related species.

Male hamsters discriminate estrous state from vaginal secretions and individuals from flank marks.

It is clear that male hamsters discriminate between the odors of individual, conspecific females, as shown by using habituation-dishabituation methods. However, it is not clear from past research whether male hamsters are able to discriminate between the odors of estrous and non-estrous females. A series of habituation-dishabituation experiments was conducted to determine whether males discriminated between different estrous cycle states using two female secretions, those from flank-glands and vaginal secretions.

Meadow voles, Microtus pennsylvanicus, have the capacity to recall the "what", "where", and "when" of a single past event.

Some non-human animals may possess the ability to recall the "what", "where", and "when" of a single past event. We tested the hypothesis that male meadow voles possess the capacity to recall the "what", "where", and "when" of a single past event associated with mate selection in two experiments. Briefly, male voles were allowed to explore an apparatus that contained two chambers.

Similarities between female meadow voles mating during post-partum oestrus and raising two concurrent litters and females raising only one litter.

In many species of small mammals, females undergo post-partum oestrus soon after delivering a litter, becoming pregnant while suckling the previous litter. Females raising two concurrent litters need to allocate many more resources to reproduction than females raising only one litter. Consequently, there may be differences between litters raised concurrently or singly.