Intense Body Contact Increases Homosexual Pair Bond Stability in Female Japanese Macaques (Macaca fuscata).

The Japanese macaque (Macaca fuscata) has become a key species for studying homosexual behavior over recent decades. With the non-conceptive nature, their same-sex consortships illustrate that individual partner preferences can exist beyond direct reproductive benefits or apparent sociosexual strategies. An open question is whether the behavior shared between partners in consortship directly affects their choice to remain with a partner. With this study, we examined behavioral aspects underlying consortship temporal patterns in these promiscuous and bisexual primates. While these patterns could be relevant in both homo- and heterosexual consortships, our study primarily focused on female-female pairs. We hypothesized that the stability of consortships (duration and occurrence) is influenced by a pair's sexual behavior, mutual sexual stimulation, and close affiliative inter-mount behaviors involving high-intensity body contact. A semi-free population of Japanese macaques was observed over one mating season. In total, 40 h of focal data on female-female consortship behaviors were analyzed. Forty-six percent of all sexually mature females engaged in homosexual interactions. Our behavioral analyses of female-female pairs found that close body contact, rather than grooming or sexual interactions, was correlated with the stability of homosexual consortships. The greater the amount of huddling and embracing a pair engaged in, the more likely they were to stay together and reunite again. However, the frequency of mounting, rubbing or thrusting had no discernable effect on consortship stability. The results of this study thus add important knowledge to partner qualities in promiscuous primates as well as to inter-group differences of homosexual behavior in Japanese macaques.

Effect of gluten diet on blood innate immune gene expressions and stool consistency in Spix's Saddleback Tamarin (Leontocebus fuscicollis) raised in captivity.

The callitrichids are non-human primates that feed on insects and plant matter in nature, but in captivity, they are fed mostly an artificial diet containing amounts of gluten, in their toxic forms in items such as wheat, barley and rye. The aim of this research was to estimate the blood ß-defensin and Toll like receptor 5 (TLR5) gene expressions and to analyze the stool consistency (firm, soft, diarrheic) in Leontocebus fuscicollis raised in captivity. Blood samples of animals under gluten-free and gluten diets were collected and their fecal output quality was periodically monitored and classified during the course of the study. Gene expression was evaluated using real-time PCR. The stool consistencies of individuals fed a gluten diet were most frequently soft or diarrheic, while it was mostly normal in individuals fed a gluten-free diet. ß-Defensin expression increased in individuals fed a gluten diet, but decreased after 15 days. Expression normalized between 30 and 45 days on a gluten-free diet. However, expression of the TLR5 gene did not change under a gluten diet. A gluten diet affects stool quality, and brings about an immediate increase in blood ß-defensin expression in the beginning but decreases after 15 days.

Hematological and biochemical parameters of Spix's Saddleback Tamarin (Leontocebus fuscicollis) raised in captivity.

The Spix's Saddleback Tamarin, Leontocebus fuscicollis is widely distributed across the Amazon region, but is endangered. This species is serving an important role in biomedical research in captivity. However, reference values for hematological and biochemical parameters are required for the proper characterization of the species. It was therefore the objective of our research to establish these parameters taking into consideration sex and body mass differences in healthy adult Spix's saddleback tamarins. Collecting 2 mL of blood from each individual, 20 animals were examined (7 males, 13 females), and hematological and biochemical parameters were determined using commercial kits. Of the sixteen variables measured, only red blood cell (RBC), hemoglobin (Hb) and hematocrit (Ht) values were significantly higher in males (7.12 ± 0.98 106/mm, 14.98 ± 1.25 g/dL and 48.71 ± 4.91%, respectively), while red cell distribution width (RDW) was higher in females (14.58 ± 1.89%). Of the biochemical parameters measured, only gamma-glutamyl transferase (GGT) enzyme showed higher activity in females (8.08 ± 4.87 U/L), and a high glucose concentration range was observed (102.0 to 521.0 mg/dL) for both sexes. These parameters established with reference ranges for healthy adults provide a reliable reference source for the interpretation of laboratory housed saddleback tamarin.