Proximity and preening in captive Humboldt penguins.

Group-living animals, including penguins, exhibit affiliative behaviors such as grooming (preening) and proximity. Such behaviors in non-primate animals have been less studied than those in primates. Our research focused on 20 identifiable Humboldt penguins in a zoo, analyzing kin relationships and reciprocity in preening and proximity by employing a 5-minute scan sampling method to observe and record individual behavior. Our findings revealed that preening and proximity were more prevalent among mate pairs. However, among non-mate pairs, such behaviors were more commonly observed between siblings and parent-offspring pairs. Notably, the individuals preened on each other simultaneously in all instances. This study highlights the potential influence of kin selection in shaping the affiliative behavior of penguins. Additionally, our findings indicate that penguins gain benefits from mutual preening. This study contributes to our understanding of social behaviors in non-primate species and emphasizes the need for further comparative studies of various animal taxa to elucidate the evolution of sociality.

Diet-related factors strongly shaped the gut microbiota of Japanese macaques.

Although knowledge of the functions of the gut microbiome has increased greatly over the past few decades, our understanding of the mechanisms governing its ecology and evolution remains obscure. While host genetic distance is a strong predictor of the gut microbiome in large-scale studies and captive settings, its influence has not always been evident at finer taxonomic scales, especially when considering among the recently diverged animals in natural settings. Comparing the gut microbiome of 19 populations of Japanese macaques Macaca fuscata across the Japanese archipelago, we assessed the relative roles of host genetic distance, geographic distance and dietary factors in influencing the macaque gut microbiome. Our results suggested that the macaques may maintain a core gut microbiome, while each population may have acquired some microbes from its specific habitat/diet. Diet-related factors such as season, forest, and reliance on anthropogenic foods played a stronger role in shaping the macaque gut microbiome. Among closely related mammalian hosts, host genetics may have limited effects on the gut microbiome since the hosts generally have smaller physiological differences. This study contributes to our understanding of the relative roles of host phylogeography and dietary factors in shaping the gut microbiome of closely related mammalian hosts.

Behavioral responses of solicitors after failure to receive grooming in Macaca fuscata.

Grooming is one of the most common cooperative behaviors among several animal species. However, the tactics used to cope with uncooperative partners in grooming interactions remain unclear. Japanese macaques (Macaca fuscata) solicit grooming from partners through postural behaviors, but may not necessarily receive grooming. This study investigated the behavior of female Japanese macaques after they solicited but did not receive grooming. We predicted that unsuccessful solicitors would engage in grooming interactions with uncooperative partners if they were affiliated. If they were not affiliated, the solicitors would not do so and may seek grooming interactions with other grooming partners. We used a focal-animal sampling method, targeting 17 females at Katsuyama, Okayama Prefecture, Japan. We recognized affiliative relationships by measuring close spatial association. After unsuccessful solicitation, females tended to scratch themselves, suggesting that solicitors may experience anxiety or distress when they do not receive grooming. They also tended to be proximate with affiliated partners after solicitation, regardless of whether the solicitors received grooming from their partners. In contrast, when solicitors failed to receive grooming from unaffiliated partners, their subsequent proximity was lower than when they were groomed. Moreover, unsuccessful solicitors were likely to engage in grooming interactions with affiliated partners who were uncooperative (receivers of unsuccessful solicitations). However, they were less likely to engage in grooming interactions with unaffiliated partners and instead engaged in grooming interactions with other nearby partners. These findings indicate that female Japanese macaques decide whether to engage in grooming interactions with uncooperative partners who have not groomed solicitors based on affiliative relationships and the availability of other grooming partners. It is probable that, when the cost of searching for a grooming partner is low, female Japanese macaques are likely to switch partners, potentially leading to an increase in the benefits obtained from grooming interactions.

Male care in a free-ranging group of Japanese macaques (Macaca fuscata).

Among the Macaca species, adult male Japanese macaques are the least likely to perform male care (i.e., affiliative interactions between adult males and immatures, including holding, carrying, and grooming); however, they perform male care for infants, albeit infrequently. We examined 17 cases of male care observed for the first time when the immature was younger than 1 year of age. Eleven of the 31 adult males who remained as central males during the 30-year observation period performed male care. Their age and dominance rank did not influence the occurrence of male care. Most cases were first recorded between the last part of the mating season and the first part of the birth season (January-March), whereas male care was rarely observed during the mating season (October-December). In 12 of the 17 cases, male care ceased within 6 months after the first observation, whereas in the remaining cases, it continued for at least 1 year. In 15 of the 17 cases, males tended to perform male care for matrilineally unrelated female infants of low-ranking mothers. In some cases, the male and infant mother showed grooming interactions for 6 months both before and after the start of male care, whereas such grooming interactions were never recorded either before or after the start of male care in other cases. We also examined some hypotheses on male-immature associations and the probable benefits that males and infants might acquire through male care.

Individual recognition of monkey (Macaca fuscata) and human (Homo sapiens) images in primatologists.

How experience affects the flexibility of facial identity recognition in adulthood is not fully understood. Primatologists are an interesting type of participants investigating facial identity recognition ability and flexibility because they can recognize individual primates based on their appearance, including body and facial features, through intense training during adulthood. Consequently, this study investigates the influence of primatological experience on individual recognition ability using eye-tracking techniques and sequential 2-alternative forced-choice matching tasks with images of humans (Homo sapiens) and Japanese macaques (Macaca fuscata). Results indicated that primatologists recognized faces of Japanese macaques more accurately than did control participants, while both primatologists and control participants recognized humans' faces with high accuracy. Primatologists demonstrated better recognition of monkey images when the whole body was presented than when only the face was presented, whereas control participants did not. Compared to the control participants, primatologists looked at areas other than the monkeys' faces for a longer time when whole-body images were presented. Furthermore, primatological experience (including study period and a total number of recognizable subjects in their studies) was related to the extent to which individual recognition of monkeys depended on nonface information. Altogether, our findings indicate that primatological experience improves the viewer's ability to recognize monkeys' faces. In addition, if available, primatologists with more experience studying monkeys use information from other parts of the body to recognize individual monkeys. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Triadic grooming among adult females in a free-ranging group of Japanese macaques.

This study aimed to quantitatively describe triadic grooming bouts in a free-ranging group of Japanese macaques (Macaca fuscata). Two types of triadic grooming bouts occurred less frequently and for a shorter duration than dyadic grooming bouts: straight-line type (SL), where individual A grooms B, who then grooms C; and two-to-one type (TO), where individuals X1 and X2 groom Y. TO-type grooming was recorded more often than SL-type grooming. As in the dyadic grooming bouts, two females who had direct grooming interactions in both SL-type (i.e., between A and B or between B and C) and TO-type groomings (i.e., between X1 and Y and between X2 and Y) and two groomers who did not have direct grooming interactions in TO-type grooming were closely related to each other in more than the half of the pairs recorded. Groomers were more likely to be subordinate to groomees in triadic grooming. Almost all of the observed pairs in SL- and TO-type groomings were also recorded in dyadic grooming bouts. These findings indicate that like dyadic grooming, triadic grooming bouts are largely influenced by blood relatedness through maternal lines and dominance relationships between participants. Based on affiliative relationships maintained through dyadic grooming, triadic grooming could be influenced by such affiliative relationships and then function to strengthen bonds between participants. Possible relationships between triadic grooming and the level of social tolerance among individuals are discussed from the viewpoints of interspecies differences among macaque species and regional differences in Japanese macaques.

Japanese macaque (Macaca fuscata) mothers huddle with their young offspring instead of adult females for thermoregulation.

It is unclear whom animals select to huddle with for thermoregulation. In this study, we investigated whom Japanese macaque (Macaca fuscata) mothers huddled with-their young offspring or other adult group members-when there is need for thermoregulation. We used a focal-animal sampling method, targeting 17 females at Katsuyama, Okayama Prefecture, Japan. A majority of huddling among adult females was recorded during winter season (December, January, and February). Females who had young (0- or 1-year-old) offspring huddled less frequently with other adult females compared to females who did not have young offspring in winter. However, including young offspring, the frequency of huddling with any other individuals did not differ by whether females had young offspring. Moreover, the females who did not have young offspring huddled with other adult females more often in cloudy than in sunny weather during winter season. In contrast, females who had young offspring increased huddling with their young offspring in cloudy than in sunny weather, but did not do so with other adult females. This study indicates that Japanese macaque mothers huddle with their young offspring instead of other adult females when there is need for thermoregulation.

Emotional states after grooming interactions in Japanese macaques (Macaca fuscata).

In animal societies, the effect of grooming interactions on anxiety reduction is unclear. This study examined the effects of giving and receiving grooming on anxiety reduction in free ranging female Japanese macaques (Macaca fuscata) by measuring rates of self-scratching as an index of anxiety. In this study, the authors used a focal-animal sampling method, targeting 17 females at Katsuyama, Okayama prefecture, Japan. They evaluated affiliative relationships, which were defined by standard proximity rates, and found that females' self-scratching rates were lower after grooming affiliated partners than during matched-control periods (occurring on another day, beginning at approximately the same time of day as the corresponding postgrooming period) and not after grooming unaffiliated partners. Moreover, regardless of affiliative relationships, self-scratching rates were lower after receiving grooming than during matched-control periods. These findings did not change after excluding data in which groomer and groomee were in proximity after the grooming interaction. In addition, multivariable analysis showed that affiliative relationships, but not kinship or rank distances, were related to differences in the rates of self-scratching between giving grooming and matched-control periods. In contrast, neither affiliative relationships nor kinship nor rank distances affected differences in self-scratching rates between receiving grooming and matched-control periods. Therefore, individuals' anxiety levels decreased both after giving grooming to affiliated partners and after receiving grooming, regardless of affiliative relationships. This is the first empirical study to support the notion that giving grooming to affiliated partners is self-rewarding in Japanese macaques.

The effect of solicitations on grooming exchanges among female Japanese macaques at Katsuyama.

In group-living primates, individuals often exchange grooming with not only kin but also non-kin. We investigated the effect of soliciting behaviors on grooming exchanges in a free-ranging Japanese macaque (Macaca fuscata) group at Katsuyama. In this study, we used a focal animal sampling method, targeting 14 females. Data were collected for 15.75 ± 2.67 (mean ± SD) hours per focal female. We classified female-female pairs into three pair types: kin pairs, affiliated non-kin pairs, and unaffiliated non-kin pairs. Females received grooming more frequently when they solicited after grooming their partners than when they did not solicit in all pair types. In addition, females received grooming less frequently when they did not groom their unaffiliated non-kin partners before soliciting; prior grooming was not needed to receive grooming from kin or affiliated non-kin partners. The degree of grooming reciprocity did not differ according to the frequency with which females in kin or affiliated non-kin pairs solicited after grooming. On the other hand, grooming reciprocity between unaffiliated non-kin females was more balanced when they solicited frequently after grooming, as compared with when they did not. In conclusion, our study suggests that soliciting behaviors promote grooming exchanges in female Japanese macaques.

Perampanel: a novel, orally active, noncompetitive AMPA-receptor antagonist that reduces seizure activity in rodent models of epilepsy.

PURPOSE: To assess the pharmacology of perampanel and its antiseizure activity in preclinical models. Perampanel [2-(2-oxo-1-phenyl-5-pyridin-2-yl-1,2-dihydropyridin-3-yl) benzonitrile] is a novel, orally active, prospective antiepileptic agent currently in development for refractory partial-onset seizures. METHODS: Perampanel pharmacology was assessed by examining changes in intracellular free Ca(2+) ion concentration ([Ca(2+) ](i) ) in primary rat cortical neurones, and [(3) H]perampanel binding to rat forebrain membranes. Antiseizure activity of orally administered perampanel was examined in amygdala-kindled rats and in mice exhibiting audiogenic, maximal electroshock (MES)-induced, pentylenetetrazole (PTZ) -induced, or 6 Hz-induced seizures. KEY FINDINGS: In cultured rat cortical neurones, perampanel inhibited α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-induced increases in [Ca(2+) ](i) (IC(50) 93 nm vs. 2 µm AMPA). Perampanel had a minimal effect on N-methyl-d-aspartate (NMDA)-induced increases in [Ca(2+) ](i) , and only at a high concentration (30 µm). [(3) H]Perampanel binding to rat forebrain membranes was not significantly displaced by glutamate or AMPA but was displaced by the noncompetitive AMPA receptor antagonists CP465022 (K(i) 11.2 ± 0.8 nm) and GYKI52466 (K(i) 12.4 ± 1 µm). In mice, perampanel showed protective effects against audiogenic, MES-induced, and PTZ-induced seizures (ED(50) s 0.47, 1.6, and 0.94 mg/kg, respectively). Perampanel also inhibited 6 Hz electroshock-induced seizures when administered alone or in combination with other antiepileptic drugs (AEDs). In amygdala-kindled rats, perampanel significantly increased afterdischarge threshold (p<0.05 vs. vehicle), and significantly reduced motor seizure duration, afterdischarge duration, and seizure severity recorded at 50% higher intensity than afterdischarge threshold current (p<0.05 for all measures vs. vehicle). Perampanel caused dose-dependent motor impairment in both mice (TD(50) 1.8 mg/kg) and rats (TD(50) 9.14 mg/kg), as determined by rotarod tests. In mice, the protective index (TD(50) in rotarod test/ED(50) in seizure test) was 1.1, 3.8, and 1.9 for MES-induced, audiogenic, and PTZ-induced seizures, respectively. In rat, dog, and monkey, perampanel had a half-life of 1.67, 5.34, and 7.55 h and bioavailability of 46.1%, 53.5%, and 74.5%, respectively. SIGNIFICANCE: These data suggest that perampanel is an orally active, noncompetitive, selective AMPA receptor antagonist with potential as a broad spectrum antiepileptic agent.

Altered expression of glutamate transporters in experimental autoimmune encephalomyelitis.

Amelioration of experimental autoimmune encephalomyelitis (EAE) by blockade of the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptor, 2,3-dihydroxy-6-nitro-7-sulfamoylbenzo(f)quinoxaline (NBQX), has been recently demonstrated [Nat. Med. 6 (2000) 67; Nat. Med. 6 (2000) 62]. However, the mechanisms underlying regulation of the extracellular glutamate concentration in EAE are unclear. To address this, we examined the expression of three distinct Na(+)-dependent glutamate transporters (GLT-1, GLAST and EAAC1) in the spinal cord of the Lewis rat EAE. EAE induced a dramatic increase in EAAC1 protein and mRNA levels, which corresponded closely with the course of neurological symptoms. In contrast, the levels of GLT-1 and GLAST protein were down-regulated in the spinal cord at the peak of disease symptoms, and no recovery was observed after remission. Furthermore, these changes in GLT-1, GLAST and EAAC1 expression were suppressed by treatment with NBQX. These results suggest that AMPA receptor activation precedes the altered expression of glutamate transporters, and that the dysregulation of extracellular glutamate concentration might play a critical role in pathological changes and neuronal dysfunction in EAE.