Sexual Signalling in Propithecus verreauxi: Male “Chest Badge” and Female Mate Choice

Communication, an essential prerequisite for sociality, involves the transmission of signals. A signal can be defined as any action or trait produced by one animal, the sender, that produces a change in the behaviour of another animal, the receiver. Secondary sexual signals are often used for mate choice because they may inform on a potential partner's quality. Verreaux's sifaka (Propithecus verreauxi) is characterized by the presence of two different morphs of males (bimorphism), which can show either a stained or clean chest. The chest becomes stained by secretions of the sternal gland during throat marking (rubbing throat and chest on a vertical substrate while smearing the scent deposition). The role of the chest staining in guiding female mate choice was previously hypothesized but never demonstrated probably due to the difficulty of observing sifaka copulations in the wild. Here we report that stained-chested males had a higher throat marking activity than clean-chested males during the mating season, but not during the birth season. We found that females copulated more frequently with stained-chested males than the clean-chested males. Finally, in agreement with the biological market theory, we found that clean-chested males, with a lower scent-releasing potential, offered more grooming to females. This “grooming for sex” tactic was not completely unsuccessful; in fact, half of the clean-chested males copulated with females, even though at low frequency. In conclusion, the chest stain, possibly correlated with different cues targeted by females, could be one of the parameters which help females in selecting mates

Mating First, Mating More: Biological Market Fluctuation in a Wild Prosimian

In biology, economics, and politics, distributive power is the key for understanding asymmetrical relationships and it can be obtained by force (dominance) or trading (leverage). Whenever males cannot use force, they largely depend on females for breeding opportunities and the balance of power tilts in favour of females. Thus, males are expected not only to compete within their sex-class but also to exchange services with the opposite sex. Does this mating market, described for humans and apes, apply also to prosimians, the most ancestral primate group? To answer the question, we studied a scent-oriented and gregarious lemur, Propithecus verreauxi (sifaka), showing female dominance, promiscuous mating, and seasonal breeding. We collected 57 copulations involving 8 males and 4 females in the wild (Berenty Reserve, South Madagascar), and data (all occurrences) on grooming, aggressions, and marking behaviour. We performed the analyses via exact Spearman and matrix correlations. Male mating priority rank correlated with the frequency of male countermarking over female scents but not with the proportion of fights won by males over females. Thus, males competed in an olfactory tournament more than in an arena of aggressive encounters. The copulation frequency correlated neither with the proportion of fights won by males nor with the frequency of male countermarking on female scents. Male-to-female grooming correlated with female-to-male grooming only during premating. Instead, in the mating period male-to-female grooming correlated with the copulation frequency. In short, the biological market underwent seasonal fluctuations, since males bargained grooming for sex in the mating days and grooming for itself in the premating period. Top scent-releasers gained mating priority (they mated first) and top groomers ensured a higher number of renewed copulations (they mated more). In conclusion, males maximize their reproduction probability by adopting a double tactic and by following market fluctuations

Stranger to Familiar: Wild Strepsirhines Manage Xenophobia by Playing

The power of play in limiting xenophobia is a well-known phenomenon in humans. Yet, the evidence in social animals remains meager. Here, we aim to determine whether play promotes social tolerance toward strangers in one of the most basal group of primates, the strepsirhines. We observed two groups of wild lemurs (Propithecus verreauxi, Verreaux's sifaka) during the mating season. Data were also collected on nine visiting, outgroup males. We compared the distribution of play, grooming, and aggressive interactions across three conditions: OUT (resident/outgroup interactions), IN (resident/resident interactions in presence of outgroups) and BL-IN (baseline of resident/resident interactions in absence of outgroups). Play frequency between males was higher in OUT than in IN and BL-IN conditions; whereas, grooming was more frequent in IN than in OUT and BL-IN conditions. Aggression rates between resident and outgroup males were significantly higher than those between residents. However, aggressions between resident and outgroup males significantly decreased after the first play session and became comparable with resident-resident aggression levels. The presence of strangers in a well-established group implies the onset of novel social circumstances, which sifaka males cope with by two different tactics: grooming with ingroup males and playing with outgroup ones. The grooming peak, concurrently with the visit of outgroups, probably represents a social shield adopted by resident males to make their pre-existing affiliation more evident to the stranger “audience”. Being mostly restricted to unfamiliar males, adult play in sifaka appears to have a role in managing new social situations more than in maintaining old relationships. In particular, our results indicate not only that play is the interface between strangers but also that it has a specific function in reducing xenophobia. In conclusion, play appears to be an ice-breaker mechanism in the critical process that “upgrades” an individual from stranger to familiar

Induction of autophagy by spermidine promotes longevity.

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Evolving trends in the management of acute appendicitis during COVID-19 waves. The ACIE appy II study

Background: In 2020, ACIE Appy study showed that COVID-19 pandemic heavily affected the management of patients with acute appendicitis (AA) worldwide, with an increased rate of non-operative management (NOM) strategies and a trend toward open surgery due to concern of virus transmission by laparoscopy and controversial recommendations on this issue. The aim of this study was to survey again the same group of surgeons to assess if any difference in management attitudes of AA had occurred in the later stages of the outbreak. Methods: From August 15 to September 30, 2021, an online questionnaire was sent to all 709 participants of the ACIE Appy study. The questionnaire included questions on personal protective equipment (PPE), local policies and screening for SARS-CoV-2 infection, NOM, surgical approach and disease presentations in 2021. The results were compared with the results from the previous study. Results: A total of 476 answers were collected (response rate 67.1%). Screening policies were significatively improved with most patients screened regardless of symptoms (89.5% vs. 37.4%) with PCR and antigenic test as the preferred test (74.1% vs. 26.3%). More patients tested positive before surgery and commercial systems were the preferred ones to filter smoke plumes during laparoscopy. Laparoscopic appendicectomy was the first option in the treatment of AA, with a declined use of NOM. Conclusion: Management of AA has improved in the last waves of pandemic. Increased evidence regarding SARS-COV-2 infection along with a timely healthcare systems response has been translated into tailored attitudes and a better care for patients with AA worldwide

Back to Prosimians: new evidence on play behaviour and its possible adaptive roles

Play can be defined as all activity that appears to an observer to have no obvious immediate benefits for the performer, but which involves motor patterns typical of serious functional contexts, such as agonistic, anti-predatory, and mating behaviour (Martin & Caro 1985; Pellis & Pellis 1996; Bekoff 2001; Burghardt 2005). In juveniles play seems to have a role in developing and training motor skills by enhancing musculoskeletal development and cardiovascular system (Byers & Walker 1995) and by practising specific survival skills (Spinka et al. 2001). However, social play can be also fruitful at an immediate level in manipulating and testing social relationships (Breuggeman 1978; Drea et al. 1996; Palagi 2009), reducing tension (Palagi et al. 2004, 2006, 2007), and increasing social cohesiveness (Thompson 1998). Play challenges psychologists to discover its consequences on behavioral development, anthropologists to identify its role in the evolution of social and cognitive skills, and evolutionary biologists to search for the functions of an apparently nonfunctional behavior (Burghardt, 2005). Even though we are far from a satisfactory knowledge-level on play, in the last two decades many efforts have been made to better understand and clarify some aspects of this behavior. Indeed, most of these efforts were especially focused on the potential meaning of play behavior. Play is a multifunctional phenomenon because its roles may vary according to a number of different factors such as species, age, sex, and relationship quality of the players. For this reason, a comparative approach in the study of animal play is needed to rigorously assess the relative importance of different functions of play for different species (Fagen 1981). To date, within Primates, the research on play behaviour has mostly focused on Haplorhines rather than Strepsirhines that have been almost completely neglected. Lemurs, which are relatively small brained, form an independent primate radiation and represent the most primitive group-living primates (Armstrong 1985; Tattersall 1982). Moreover, some lemur species share common features with many Haplorhines species, such as the diurnal habit, high level of sociality and the presence of visual communication (Jolly 1966; Pereira et al 1988; Palagi 2009). Altogether, these characteristics represent the basis for the study of play behaviour, particularly for social play (the most sophisticated form of play). In this perspective, investigation within lemur species may represent an opportunity for looking for possible adaptive roles of such complex behaviour. I selected ringtailed lemurs (Lemur catta – family Lemuridae) and sifaka (Propithecus verreauxi – family Indridae) as model species in this study for the following reasons: The two species live in sympatry in the study-site, consequently the data collection was not affected by any difference in external environmental pressures. Moreover, the data considered for this study were collected for both species in the same season, the wet season. The two species are diurnal and lives in multimales/multifemales groups where each sex and age classes are represented, thus allowing the analyses on social play in this respect. Although the two species are phylogenetically close-related, they show species-specific differences in several behavioural features, such as the social structure in terms of inter-individual relationships and level of despotism. The goal of the study is to deeply investigate the use of play behaviour within ringtailed lemurs and sifaka according to their species-specifics behavioural features in order to add key-interpretations on play and its possible functions and adaptive roles. Here I first put in relation play behaviour with the striking different habitat exploitation, anatomical and locomotion constraints shown by the two study species. Indeed, ringtailed-lemur is the most terrestrial lemur (mainly using quadrupedal locomotion) and sifaka one of the most arboreal one (mainly using clinging and leaping locomotion habits). Secondly, I based the research analyses on social behaviour features shown by the two study species. Ringtailed lemurs live in a prominent despotic society expressed by: i) inter-individual relationships, which are strongly codified according to rank rules (Kappeler 1990; Palagi et al 2005); ii) the presence of relatively diverse set of signals and ritualization, usually used for maintaining unambiguous, public dominants relationships (Submissive Spat-Grimace, Yawning and Gnashing, then Stink fight); ii) high level of territoriality, making ringtailed lemurs groups completely “sealed” to outsiders (Huntingford &Turner 1987; Beckoff 1975, 1977). Conversely sifaka live in a more tolerant society expressed by: i) female dominance over males, translated more into feeding priority than into general despotic relationships (Richard 1974); ii) absence of ritualization or meta-communication signals; ii) living in permeable groups, particularly during the mating season when outgroup males visit other groups for mating purposes (Brockman and Whitten 1996; Brockmann 1999; Ostner & Kappeler 2004; Norscia et al. 2009). In this perspective, if play is a multifunctional phenomenon because its roles may vary according to a number of different factors such as species, age, sex and inter-individual relationship among players (Fagen 1981; Burghardt 2005; Palagi 2006, 2008, 2009; Palagi et al. 2007), I expect to find different functions in the use of play within the two species. Moreover, due to the natural territorial overlapping characterizing the study site, if play is used as a means for copying with “social novelty”, I expect to find within each species a different use of such means in presence of external lemur groups. Methods I conducted this study in the Ankoba secondary forest (40-ha) of the Berenty Reserve in Southern Madagascar. The site is characterized by two main climatic periods: the wet season (from October to March) and the dry season (from April to September) (Jolly et al. 2006). At Berenty, ringtailed lemurs and sifaka live in sympatry with another species (showing cathemeral habits) the brown lemurs (Eulemur fulvus). The three species naturally have overlapping ranges and dietary so they likely compete for similar foods during times of scarcity (dry season). I collected data during two different periods to cover the two seasons: - First period of observation – wet season (Nov 2006 – Feb 2007). I observed 2 groups of ringtailed lemurs composed by 9 individuals (4 adult males, 1 infant male, 3 adult females and 1 sub-adult female) and 16 individuals (4 adult males, 2 sub-adult males, 2 infant males, 6 adult females, 1 sub-adult female and 1 infant female) respectively. I observed 2 groups of sifaka composed by 8 individuals (5 adult males, 2 adult females, 1 sub-adult female) and 6 individuals (1 adult male, 2 sub-adult males, 2 adult females and 1 sub-adult female) respectively. In addition, I also collected standardized data on 9 outgroup males started visiting my study groups two months after the beginning of the observations and one month before the first mating day (Norscia et al. 2009). - second period of observation – dry season (Mar 2008 – Jul 2008). I observed 2 groups of ringtailed lemurs composed by 13 individuals (4 adult males, 1 juvenile male, 4 adult females and 2 juvenile females) and 19 individuals (5 adult males, 3 infant males, 8 adult females and 3 infant females) respectively. For sifaka, I observed the same groups of the previous observational period; nevertheless I found some changes in group composition. The two groups of sifaka were composed by 8 individuals (3 adult males, 1 sub-adult males, 3 adult females and 1 juvenile female) and 7 individuals (2 adult males, 2 juvenile males, 2 adult females and 1 juvenile female) respectively. Behavioural data have been collected basing on ethograms that include solitary and social behaviours (affinitive, aggressive, submissive and neutral items). For data collection I used focal animal sampling, all occurrences and ad libitum methods (Altman 1976). - focal sampling. For ringtailed lemurs a total of 729h of observation (400 for the first and 329h for the second observational period) has been collected. For sifaka a total of 1.019h of observation (501h for the first and 518h for the second observational period) has been collected. - All occurrences. For ringtailed lemur a total of 831h of observation (350 for the first and 481h for the second observational period of observation) has been collected. For Sifaka a total of 653h (273h for the first and 380h for the second observational period of observation) has been collected. Since the number of play session occurred during the second period of observation (dry season) was low (only 2 sessions for ringtailed lemurs and 14 for sifaka), I focalised the data analyses only on the first period of data collection. I used nonparametric statistical tests (Siegel & Castellan, 1988; Lehener, 1996; Zar, 1999) for data processing. Results and discussion The occurrence of play in sifaka and ringtailed lemurs at different forest layers seems to be related to their anatomical and locomotion constraints, and habitat exploitation. Within ringtailed lemurs play occurs also among adults other than immature individuals. Here, I show that play mostly occurs among subordinates individuals (adult males and sub-adults); whereas low levels of play occur among high-ranking females whose dominance is stable and unquestionable. Therefore, play seems to be used by ringtailed lemurs as an “informative and safer tool” for those individuals who need to improve their fighting abilities and assess the strength/weakness of possible competitors. Such tool seems to be helpful in improvement of dominant status (peripheral males to become “prime”, sud-adult females minimizing the risk of being “targeted”) (“social assessement hypothesis” Geist 1982; Jones 1983; Pellis et al. 1993; Paquette 1994). Moreover, the presence of relatively diverse set of signals and ritualization are predictive of a despotic society (Huntingford &Turner 1987; Beckoff 1975, 1977). Such signals are used to maintain unambiguous, public dominants relationships (Submissive Spat-Grimace, Yawning and Gnashing, then Stink fight). Ringtailed lemurs use their tail as a signals of communication in different aspects of social life, such as agonistic, marking and play behaviour. In particular, “anoint tail” (olfactory signal) and “wave tail” (visual signal) are used in different combinations both in agonistic and playful contexts toward competitors or playmates (Jolly 1966; Palagi 2009). Here I provide evidence on the use of play signals (tail play) which have been retained for playful activity (tail-play) to avoide “misinterpretation” during the riskiest form of play (rough play). In particular, as stink fight are used in dyadic aggressive encounters, I proved that tail play reaches the most effectiveness during dyadic play. In addition, during polyadic play sessions, play itself seems to be a means for signalling the “social status” and maintaining the play session, thus explaining the decreased level of tail play found in polyadic sessions. Finally, the high level of despotism, expressed also by high level of territoriality, makes ringtailed lemur completely “sealed” to outsiders. No “intruders” are admitted into the group without engaging in overt fights beforehand (Jolly 1966). In presence of possible food competitors represented by conspecifics or alien species play seems to have been retained for two possible roles: realising stress of group-members during mild stress situation (Pellis 2002) or, once more, as an “honest signal” for convey information towards competitors about the proper aggressive intent and/or the fighting ability (the “Zahavi’s handicap principle” - Zahavi 1975). On the other hand, sifaka live in a more tolerant society compared to ringtailed lemurs. Within this species I found evidence that play has not be retained into adulthood for courtship purposes (the observational period fall into the mating season). On the contrary, non-sexual play is expressed for coping with the onset of novel social circumstances: the presence of temporary outgroup males. Indeed, play seems to be a means to test emergent relationships between unfamiliar individuals and can work as a signal of non-agonistic intent in a sort of short-range communication and/or as a means for social and self-assessment. In presence of possible social tension induction (mild stress condition) due to the presence of new individuals, sifaka seem to use play for stress realising. The lack of meta-communication signals reflects the difficulty to maintain the playful mood without incurring in a high risk of aggression, so that sifaka males adjust their playful tactics as a function of playmates’ group membership while playing longer with residents in the riskiest form of play (rough play). Finally, play while arising spontaneously, independently from the presence of previous affinitive behaviour with unfamiliar individuals suggests that play it may represent a bridge between the two unfamiliar subjects. In conclusion, by the light of results found, here I propose a new possible hypothesis of play behaviour: “the ice-breaker hypothesis”; that is play functions as a mechanism which enhances friendly interactions in the critical process that leads a “stranger” to become “familiar”

L'"etica" del gioco: benefici a breve e a lungo termine in una colonia di gorilla (Gorilla gorilla gorilla)

Il comportamento di gioco come facente parte della comunicazione sociale nei Primati è stato soltanto negli ultimi anni oggetto di numerosi studi; sulla base delle definizioni scaturite nasce l’ esigenza di supportare o confutare quanto scarsamente ritrovato in letteratura sul Gorilla di pianura, provando ad ampliarne le conoscenze in merito. Lo studio è stato condotto sulla colonia di Gorilla gorilla gorilla ospitata presso il Parco Primati “Apenheul” di Apeldoorn (Paesi Bassi), costituita da 16 individui ( 1 maschio adulto, 5 femmine adulte, 2 adolescenti, 5 giovani, 3 infanti). I metodi di osservazione utilizzati sono: 1) focal-animal sampling con cui sono stati registrati tutti i comportamenti di un animale focale nell’arco di 30 minuti per un totale di 723 ore; 2) scan sampling con cui sono stati registrati i comportamenti di gioco e grooming di tutti gli individui della colonia ad intervalli regolari di 5 minuti per un totale di 378 ore; 3) sampling all occurrences con cui sono stati registrati tutti i comportamenti aggressivi e tutte le interazioni sessuali tra gli individui per un totale di 723 ore; 4) ad libitum sampling con cui sono stati annotati particolari comportamenti utili per l’interpretazione dei dati. L’ analisi parte da uno studio generale del comportamento di gioco all’interno della colonia osservata, per poi addentrarsi nelle specifiche funzioni e ruoli di un comportamento considerato “ambiguo” ma evidentemente presente nella vita di questi animali. Una società despotica come quella del Gorilla presenta l’ attività ludica solo tra gli immaturi del gruppo e non tra gli adulti, per comprendere tale fenomeno è stata indagata l’ eventuale presenza di benefici a breve termine dell’ uso del gioco tra chi ancora non è un adulto. La situazione di semicattività in cui gli animali si trovano, ci ha dato la possibilità di condurre osservazioni in condizioni controllate. Provando così che i livelli di gioco aumentano là dove c’è una ristrettezza spaziale e nel periodo appena precedente alla distribuzione del cibo, si può pensare al comportamento di gioco come “riduttore” di tensione in momenti di forte conflitto di interesse tra i membri del gruppo. Il riconoscimento dello stato di gioco ammette la presenza di segnali chiari ed evidenti che tolgano ogni ambiguità interpretativa a chi osserva (lo sperimentatore) e a chi agisce (l’ animale). La frequente presenza di Play face e Full play face (I segnali più comuni ritrovati nei primati) solo nelle sessioni ludiche e in nessun altro contesto, anche nel gorilla, supporta la teoria che l’ animale necessiti di un segnale da comunicare al compagno a conferma del fatto che in corso ci sia un gioco e non altro. Nel caso specifico della colonia, il segnale più usato è quello più evidente la Full Play face, per mantenere proprio quelle sessioni di gioco più vigorose che potrebbero risultare anche le più ambigue. Il gioco assume forma comunicativa anche se svolto dal singolo individuo, non condiviso, quindi come gioco solitario. L’analisi ha evidenziato in esso una significativa potenzialità nell’ innescare a sua volta un gioco sociale. Il carattere attrattivo per l'inizio di una sessione ludica in compagnia ha suggerito la possibilità, non ancora del tutto esplorata, che il gioco solitario possa a sua volta rientrare nella definizione di segnale di gioco

Stress and Play Fluctuation in wild Lemur catta

Strepsirhines have been neglected in the study of animal play. Yet, data from a wide array of primate taxa are needed to understand role, functions and social determinants of play. We investigated play behaviour in wild ringtailed lemurs (Lemur catta) at the Berenty Reserve (Madagascar) where two other sympatric lemur species, and potential resource competitors, live (Propithecus verreauxi and Eulemur fulvus). We followed two groups of ringtailed lemurs (9 and 16 individuals) from November 2006 to February 2007. We evaluated play fluctuation during possible stressful conditions, such as the presence of neighbour groups of conspecifics (C), the presence of groups of other lemur species (NC). We considered the absence of any other group (A) as the control condition. We first verified whether the presence of other groups did increase stress levels in the study groups. Stress levels were measured via scratching, which previous studies have proven as a reliable indicator of anxiety in human and non-human primates. Scratching rates in the study animals were higher in presence of other groups (C+NC) rather than in their absence (A). Overall play rates were highest when other groups were nearby. In presence of NC groups, play rates decreased as NC groups approached the study groups. Instead, when only C groups were in sight, play rates increased as the distance between the study groups and other conspecifics decreased. Moreover, play was highest during extra-group aggressive encounters (involving C groups) whereas it was suppressed during intra-group fights. Our results suggest that play fluctuate in response to different stressful conditions and may be used as a mechanism to cope with anxiety

Scratching around mating: Factors affecting anxiety in wild Lemur catta

Scratching has been successfully used to detect anxiety, a proxy for stress, in primates, from strepsirrhines to Homo sapiens. Here, we investigated the fluctuation of scratching in Lemur catta during the mating season. In particular we evaluated whether scratching (1) varied according to sex and rank differences, (2) increased in the period of maximum stress (around the mating days), and (3) was reduced by grooming. At Berenty (South Madagascar), we followed two lemur groups (23 adult/subadult individuals) and gathered data on self-scratching, aggression, and grooming. Based on perineal area features, we recognized two periods: low swelling (LS), with no estrus female, and high swelling (HS), when at least one female was in estrus. We predicted that aggressive behaviors and anxiety-related scratching would covary. Indeed, scratching peaked in HS, when aggression was also highest. In agreement with previous literature, this result suggests that conflicts around estrus days may raise anxiety levels in the social group. We expected scratching levels to be highest in males because they aggressively compete for females and are subject to mate choice and repeated attacks by dominant females. Instead, the scratching rates were similar in males and females, probably because the high competition, which involves both sexes, dampened intersexual differences. In contrast to our prediction, scratching was not rank dependent, probably because animal ranking positions changed from LS to HS. Finally, we showed that, in ring-tailed lemurs, as well as in other primates, scratching decreases after reciprocal grooming in both periods. This finding provides the first evidence that grooming could assist in reducing anxiety in strepsirrhines