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The South American camelids are a domesticated species adapted to the high Andes, they are considered as a species of induced ovulation. In these species, so that the release of the oocyte occurs, a neuroendocrine interaction and stimulation during intercourse (which have to lasts on average 18 minutes) is necessary. In recent years, several studies have demonstrated the presence of an inducing factor for the ovulation found in the seminal plasma of the male that is crucial for ovulation to occurs in camelids. From 1968 researches were initiated to confirm and determine the inductor factor. The works have shown that ovulation in alpacas occurs after intramuscular and intravaginal application of seminal plasma. Recent studies showed the luteotropic effect of this factor, which is evidenced by the increase and retention of circulating concentrations of LH, the rapid change in the vascularization of the pre-ovulatory follicle and corpus luteum development, this contributes to the increase of the embryonic survival rate, due to the stimulus that causes this hormone in the pituitary to release LH, triggering an additional luteotropic effect on the corpus luteum with increased secretion of progesterone. At the field, level the results are not as manifest in relation to the results obtained when the ultrasound monitoring is performed. However, the work done by different research groups confirm the contribution of seminal plasma in increasing fertility rates and embryonic survival in domestic camelids such as alpaca and llama.

El desarrollo de las técnicas de reproducción asistida en Camélidos Sudamericanos ha sido establecido con bastante lentitud al compararlas con el desarrollo que han tenido en otras especies como son los rumiantes. Sin embargo técnicas como superovulación, transferencia de embriones y fecundación in vitro han sido abordadas en los últimos años con resultados bastante alentadores y que podrán en un futuro hacer posible de uso en forma comercial. Similar a los rumiantes las respuestas a los protocolos de superovulación continúan siendo muy variables a pesar de tener un control de la actividad ovárica al comienzo de los mismos. La recuperación de blastocistos eclosionados mediante lavado uterino continúa siendo una limitante para poder manipular al embrión posterior a su colección con otras metodologías como congelación o vitrificación. Un gran paso se ha realizado en lo que respecta a los métodos de colección de semen y su uso para la inseminación artificial o para fecundación in vitro. Así también, se ha logrado de obtener ovocitos de animales vivos utilizando punción folicular guiada por ecografía transvaginal. Quizás el impedimento más complejo para lograr un avance significativo del método de fecundación in vitro has sido la escasez en la obtención de ovocitos de matadero, una fuente muy importante de material que pudiera ser utilizado para investigación de la misma forma que lo ha sido para los sistemas in vitro en rumiantes. La intención de esta revisión es dar a conocer los principales protocolos de superovulación que han sido desarrollados hasta la fecha en llamas y alpacas.

What makes an odour pleasant or unpleasant? The inherent properties of the constituent chemical compounds, or the nose of the beholder, driven by idiosyncratic differences and culture-specific learning? Here, 582 individuals, including Tanzanian Hadza hunter-gatherers, Amazonian Tsimane' horticulturalists, Yali from the Papuan highlands and two industrialized populations (Poles, Malaysians), rated the pleasantness of 15 odour samples. We find considerable similarities in odour assessments across cultures, but our data do not fully support a claim regarding the universality of smell preferences. Despite cross-cultural similarities in olfactory assessments, probably driven by odour properties, we suggest that odour availability in ecological and cultural niches bears an undeniable effect on human odour preferences.

Music is present in every known society but varies from place to place. What, if anything, is universal to music cognition? We measured a signature of mental representations of rhythm in 39 participant groups in 15 countries, spanning urban societies and Indigenous populations. Listeners reproduced random 'seed' rhythms; their reproductions were fed back as the stimulus (as in the game of 'telephone'), such that their biases (the prior) could be estimated from the distribution of reproductions. Every tested group showed a sparse prior with peaks at integer-ratio rhythms. However, the importance of different integer ratios varied across groups, often reflecting local musical practices. Our results suggest a common feature of music cognition: discrete rhythm 'categories' at small-integer ratios. These discrete representations plausibly stabilize musical systems in the face of cultural transmission but interact with culture-specific traditions to yield the diversity that is evident when mental representations are probed across many cultures., (© 2024. The Author(s).)

Global polls have shown that people in high-income countries generally report being more satisfied with their lives than people in low-income countries. The persistence of this correlation, and its similarity to correlations between income and life satisfaction within countries, could lead to the impression that high levels of life satisfaction can only be achieved in wealthy societies. However, global polls have typically overlooked small-scale, nonindustrialized societies, which can provide an alternative test of the consistency of this relationship. Here, we present results from a survey of 2,966 members of Indigenous Peoples and local communities among 19 globally distributed sites. We find that high average levels of life satisfaction, comparable to those of wealthy countries, are reported for numerous populations that have very low monetary incomes. Our results are consistent with the notion that human societies can support very satisfying lives for their members without necessarily requiring high degrees of monetary wealth., Competing Interests: Competing interests statement:The authors declare no competing interest.

The objective of this study was to evaluate the effect of the addition of different percentages of seminal plasma (SP) during the cooling at 5 °C of alpaca spermatozoa from vas deferens. Fifteen pools of sperm from vas deferens were evaluated and then divided into four aliquots that were diluted to a final concentration of 30 × 10 6 sperm/ml with either: (1) Tris with 20% egg yolk (T-EY) (control, 0% SP), (2) T-EY with 10% SP, (3) T-EY with 25% SP, and (4) T-EY with 50% SP. Samples were cooled at 5 °C and the following sperm parameters were evaluated after 24 and 48 h of storage: motility, viability, membrane function, acrosome integrity, morphology, and chromatin condensation. Motility was also evaluated after 72 h of storage. A significant decrease in progressive and total sperm motility was observed in samples cooled with 50% SP with respect to all diluted samples, while these parameters were preserved in samples cooled with 0%, 10%, and 25% SP. The percentages of sperm viability, normal morphology, and highly condensed chromatin did not change after the cooling process and were similar between cooled samples. Although a significant decrease was observed in the percentage of spermatozoa with functional membranes and with an intact acrosome in all refrigerated samples compared to raw sperm, the greatest decrease was observed in samples cooled with 50% SP. No advantage was observed from the addition of SP to alpaca spermatozoa obtained from vas deferens and being cooled. In addition, to preserve the sperm motility of cooled samples for up to 72 h, it should be recommended to include a 10% SP in the extender., Competing Interests: Declaration of Competing Interest The authors report no declarations of interest., (Copyright © 2023 Elsevier B.V. All rights reserved.)

In the United States, children often generalize the meaning of new words by assuming that objects with the same shape have the same name. We propose that this shape bias is influenced by children's exposure to objects of different categories (artifacts and natural kinds) and language to talk about them. We present a cross-cultural study between English speakers in the United States and Tsimane' speakers in the Bolivian Amazon. We found that U.S. children and adults were more likely to generalize novel labels by shape rather than by material or color, relative to Tsimane' participants. Critically, Tsimane' children and adults systematically avoided generalizing labels to objects that shared no common features with the novel referent. Our results provide initial evidence that the relative exposure to objects of different kinds and language to talk about them can lead to cross-cultural differences on object name learning. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Humans often communicate using body movements like winks, waves, and nods. However, it is unclear how we identify when someone's physical actions are communicative. Given people's propensity to interpret each other's behavior as aimed to produce changes in the world, we hypothesize that people expect communicative actions to efficiently reveal that they lack an external goal. Using computational models of goal inference, we predict that movements that are unlikely to be produced when acting towards the world and, in particular, repetitive ought to be seen as communicative. We find support for our account across a variety of paradigms, including graded acceptability tasks, forced-choice tasks, indirect prompts, and open-ended explanation tasks, in both market-integrated and non-market-integrated communities. Our work shows that the recognition of communicative action is grounded in an inferential process that stems from fundamental computations shared across different forms of action interpretation., (© 2022. The Author(s).)

Objectives: Thirst is an evolved central homeostatic feedback system that helps regulate body water for survival. Little research has examined how early development and exposure to extreme environments and water availability affect thirst perception, particularly outside Western settings. Therefore, we compared two indicators of perceived thirst (current thirst and pleasantness of drinking water) using visual scales among Tsimane' forager-horticulturalists in the hot-humid Bolivian Amazon and Daasanach agro-pastoralists in hot-arid Northern Kenya., Methods: We examined how these measures of perceived thirst were associated with hydration status (urine specific gravity), ambient temperatures, birth season, age, and population-specific characteristics for 607 adults (n = 378 Tsimane', n = 229 Daasanach) aged 18+ using multi-level mixed-effect regressions., Results: Tsimane' had higher perceived thirst than Daasanach. Across populations, hydration status was unrelated to both measures of thirst. There was a significant interaction between birth season and temperature on pleasantness of drinking water, driven by Kenya data. Daasanach born in the wet season (in utero during less water availability) had blunted pleasantness of drinking water at higher temperatures compared to those born in the dry season (in utero during greater water availability)., Conclusions: Our findings suggest hydration status is not a reliable predictor of thirst perceptions in extreme-hot environments with ad libitum drinking. Rather, our findings, which require additional confirmation, point to the importance of water availability during gestation in affecting thirst sensitivity to heat and water feedback mechanisms, particularly in arid environments. Thirst regulation will be increasingly important to understand given climate change driven exposures to extreme heat and water insecurity., (© 2021 Wiley Periodicals LLC.)

Objectives: This study compared the prevalence of concentrated urine (urine specific gravity ≥1.021), an indicator of hypohydration, across Tsimane' hunter-forager-horticulturalists living in hot-humid lowland Bolivia and Daasanach agropastoralists living in hot-arid Northern Kenya. It tested the hypotheses that household water and food insecurity would be associated with higher odds of hypohydration., Methods: This study collected spot urine samples and corresponding weather data along with data on household water and food insecurity, demographics, and health characteristics among 266 Tsimane' households (N = 224 men, 235 women, 219 children) and 136 Daasanach households (N = 107 men, 120 women, 102 children)., Results: The prevalence of hypohydration among Tsimane' men (50.0%) and women (54.0%) was substantially higher (P < .001) than for Daasanach men (15.9%) and women (17.5%); the prevalence of hypohydration among Tsimane' (37.0%) and Daasanach (31.4%) children was not significantly different (P = .33). Multiple logistic regression models suggested positive but not statistically significant trends between household water insecurity and odds of hypohydration within populations, yet some significant joint effects of water and food insecurity were observed. Heat index (2°C) was associated with a 23% (95% confidence interval [CI]: 1.09-1.40, P = .001), 34% (95% CI: 1.18-1.53, P < .0005), and 23% (95% CI: 1.04-1.44, P = .01) higher odds of hypohydration among Tsimane' men, women, and children, respectively, and a 48% (95% CI: 1.02-2.15, P = .04) increase in the odds among Daasanach women. Lactation status was also associated with hypohydration among Tsimane' women (odds ratio = 3.35, 95% CI: 1.62-6.95, P = .001)., Conclusion: These results suggest that heat stress and reproductive status may have a greater impact on hydration status than water insecurity across diverse ecological contexts., (© 2020 Wiley Periodicals LLC.)

The use of non-commercial and commercial extenders for cooling alpaca sperm has already been reported, the latter showing certain advantages over the first. The Andromed® (AM) extender was created for use in ruminants and has also been tested in ejaculated and epididymal alpaca sperm. According to the manufacturer, this extender does not need the addition of egg yolk (EY); however, it is known that the addition of EY to some extenders improves the preservation of cooled sperm. The objective of this study therefore was to compare a non-commercial extender (Tris) with the addition of EY vs. the commercial extender AM with and without the addition of EY, for cooling alpaca sperm obtained from diverted deferent ducts. Fifteen pools of deferent duct sperm were formed using samples from two or three different males for each. Each sperm pool was evaluated and then divided into three aliquots that were diluted to a final concentration of 30 × 10 6 sperm ml-1 (0 h) with either: (1) Tris with 20% EY (T-EY), (2) AM, or (3) AM with 20% EY (AM-EY). Samples were cooled to 5°C and the following sperm parameters were evaluated after 24 and 48 h of storage: motility, viability, membrane function, acrosome integrity, morphology, and chromatin condensation. Motility was also evaluated after 72 h of storage. The samples that best preserved progressive and total sperm motility at the 24 and 48 h evaluation periods were the ones diluted with AM-EY, observing that with this extender these motility patterns decreased significantly after 72 h of storage compared to time 0 h ( p < 0.05). A significant decrease ( p < 0.05) in total and progressive motility was observed at 48 h for the T-EY and AM extender compared to 0 h. AM was the only extender in which the percentages of viable sperm decreased significantly ( p < 0.05) after 48 h of conservation. For the rest of sperm parameters evaluated, no significant differences were observed between any of the extenders at any evaluation time. The Andromed® extender with the addition of 20% EY could be an alternative option for cooling alpaca sperm obtained from deferent ducts., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The handling editor declared a past co-authorship with the authors MC., (Copyright © 2020 Bertuzzi, Torres, Huanca, Neild and Carretero.)

Biological significance of food components suggests that preferences for basic tastes should be similar across cultures. On the other hand, cultural factors play an important role in diet and can consequently influence individual preference for food. To date, very few studies have compared basic tastes preferences among populations of very diverse environmental and cultural conditions, and research rather did not involve traditional populations for whom the biological significance of different food components might be the most pronounced. Hence, our study focused on basic taste preferences in three populations, covering a broad difference in diet due to environmental and cultural conditions, market availability, dietary habits and food acquirement: 1) a modern society (Poles, n = 200), 2) forager-horticulturalists from Amazon/Bolivia (Tsimane', n = 138), and 3) hunter-gatherers from Tanzania (Hadza, n = 85). The preferences for basic tastes were measured with sprays containing supra-threshold levels of sweet, sour, bitter, salty, and umami taste solutions. We observed several interesting differences between participating societies. We found that Tsimane' and Polish participants liked the sweet taste more than other tastes, while Hadza participants liked salty and sour tastes more than the remaining tastes. Further, Polish people found bitter taste particularly aversive, which was not observed in the traditional societies. Interestingly, no cross-cultural differences were observed for relative liking of umami taste - it was rated closely to neutral by members of all participating societies. Additionally, Hadza showed a pattern to like basic tastes that are more common to their current diet than societies with access to different food sources. These findings demonstrate the impact of diet and market availability on preference for basic tastes., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The effect of free mate choice on the relative magnitude of fitness benefits has been examined among various species. The majority of the data show significant fitness benefits of mating with partners of an individual's own choice, highlighting elevated behavioral compatibility between partners with free mate choice. Similarities between humans and other species that benefit from free mate choice led us to hypothesize that it also confers reproductive benefits in Homo sapiens. To test this hypothesis, we conducted a study among three indigenous societies-the Tsimane', Yali, and Bhotiya-who employ natural birth control. In all three samples, we compared the marriages arranged by parents with the non-arranged ones in terms of number of offspring. Here, we show that there were no significant relationships between type of marriage and the total number of alive children and number of dead children among the three sampled groups. The presented study is the first to date to examine the fitness benefits of free mate choice in humans. In discussion we present limitations of our research and discuss the possibility of love having a beneficial influence in terms of the number of offspring.

The dictator game (DG) is one of the most popular methods for measuring sharing behaviors. However, the matter of goods used in the game has rarely been examined and discussed. We conducted a study in which all participants played standard version of DG in one of the three versions - "money," "food," or "daily life objects" sharing. Further, we wanted to expand the generalizability of our findings by investigating whether patterns in sharing various goods are independent of culture and the level of market integration. Thus, the study was conducted among people who function daily under the conditions of low market integration (109 Tsimane' - forager-horticulturists from Bolivian Amazon) and in a society highly integrated with the market-based economy (85 Polish people). We observed that among both Polish and Tsimane' people the participants were equally likely to share money, food and small, daily life objects with an unknown partner, which implies that generosity might not be related with the type of possessed resources. However, regardless of the kind of goods given, Tsimane' people were less eager to share with anonymous others than Polish people. We present several implications of our findings for studies on generosity and altruism.

Body height influences human mate preferences and choice. A typical finding in Western societies is that women prefer men who are taller than themselves and, equivalently, men prefer women who are shorter than themselves. However, recent reports in non-Western societies (e.g., the Himba in Namibia) challenge the view on the universality of such preferences. Here we report on male and female height preferences in two non-Western populations--the Hadza (Tanzania) and the Tsimane' (Bolivia)--and the relationships between body height preferences and the height of actual partners. In the Hadza, most individuals preferred a sexual dimorphism in stature (SDS) with the man being much taller than the woman. Preferences for SDS and actual partner SDS were positively and significantly correlated in both men and women, suggesting that people who preferred larger height differences also had larger height differences with their partners. In the Tsimane', the majority of men preferred an SDS with the man being taller than the woman, but women did not show such a preference. Unlike in the Hadza, SDS preference was not significantly correlated to actual partner SDS. We conclude that patterns of height preferences and choices in the Hadza and Tsimane' are different than those observed in Western societies, and discuss possible causes for the observed differences between non-Western and Western societies.