Abstract The Clouded Tiger Cat Leopardus pardinoides is a recently recognized Neotropical species for which ecological and natural history data are sparse. Knowledge of species distribution and elevational range are largely based upon camera trap studies, and its diet has not been examined. The objective of this study was to better define the geographical and elevational distribution of the subspecies L. pardinoides oncilla in Central America using genetically confirmed records. We also provide the first diet analysis for L. pardinoides. We conducted extensive surveys for scat samples by visual means and with a scent detection dog across mountain ranges in Panama and Costa Rica, confirmed species identity using Sanger sequencing of mitochondrial DNA, and analyzed diet composition via DNA metabarcoding. Altogether, we collected 195 confirmed L. pardinoides scats. Records were strongly associated with high elevations, with a median elevation of 2805 m, and a maximum of 3422 m. Our findings highlight core habitat for L. pardinoides in the Cordillera Talamanca mountains in the border region of Panama and Costa Rica, and we identified isolated populations from the Central Volcanic Cordillera of Costa Rica and the Central Cordillera of Panama. DNA metabarcoding detected 59 vertebrate taxa. Diet was dominated by small mammals (74% of samples), especially cricetid rodents and shrews. Birds were also commonly detected (35% of samples), while reptiles (13%) and amphibians (1.9%) were less frequent. Estimated median adult prey mass was low (25 g), indicating that the species specializes on small prey. Most vertebrate prey identified were species endemic to montane regions of Panama and Costa Rica. These findings provide valuable ecological and natural history data on Clouded Tiger Cats in Central America that will inform conservation and management of this recently recognized species.

The evolutionary history and taxonomy of the Leopardus tigrinus species complex have been studied based on several approaches, mostly employing genetic and morphological data, leading to distinct classification schemes. We approached this problem from an ecological perspective, with 2 main goals: (i) to evaluate ecological niche differences among regional L. tigrinus populations to determine the extent of ecological divergence among them; and (ii) to identify environmental barriers to historical dispersal that could have driven differentiation among the proposed groups. We modeled the ecological niche of all taxonomic/geographic groups proposed so far to comprise the L. tigrinus complex using the Maximum Entropy algorithm, and evaluated geographic and ecological niche differences among them. Furthermore, we investigated possible environmental barriers to historical dispersal that could have driven differentiation among regional groups. We evaluated 4 hypothetical barriers across 3 time periods to assess their potential historical effect. We found high ecological divergence between northeastern tigrina populations and the northern Andean and Central American tigrinas. Other groups within the L. tigrinus complex are less divergent. In addition, the Guiana Shield tigrina, where the type locality of the species is located, seems to be ecologically similar to populations from northeastern Brazil while also showing some overlap with Andean populations. The Panama center, the Llanos of Colombia and Venezuela, and the Amazon region were identified as historical barriers for tigrina dispersal across all time periods. The inferred historical barriers and ecological divergence observed in this study contribute to the inference of evolutionary differentiation among geographic groups comprising the L. tigrinus complex, revealing areas of consistently low habitat suitability that have likely contributed to divergence among regional populations. The study characterizes ecological niche differences among regional L. tigrinus populations and discovers 3 historical environmental barriers (Panama center, the Llanos of Colombia/Venezuela, and the Amazon region) that may have promoted differentiation among these groups. La historia evolutiva y la taxonom & iacute;a del complejo de especies Leopardus tigrinus se han estudiado en base a varios enfoques, en su mayor & iacute;a empleando datos gen & eacute;ticos y morfol & oacute;gicos, lo que ha llevado a distintos esquemas de clasificaci & oacute;n. Abordamos este problema desde una perspectiva ecol & oacute;gica, con dos objetivos principales: (i) evaluar las diferencias del nicho ecol & oacute;gico entre las poblaciones regionales de L. tigrinus para determinar la existencia de divergencia ecol & oacute;gica entre ellas; e (ii) identificar las barreras ambientales para la dispersi & oacute;n hist & oacute;rica de estos organismos que podr & iacute;an haber impulsado la diferenciaci & oacute;n entre los grupos propuestos. Modelamos el nicho ecol & oacute;gico de todos los grupos taxon & oacute;micos/geogr & aacute;ficos propuestos hasta ahora para comprender el complejo L. tigrinus utilizando el algoritmo de M & aacute;xima Entrop & iacute;a y evaluamos las diferencias geogr & aacute;ficas y ecol & oacute;gicas de nicho entre ellos. Adem & aacute;s, investigamos posibles barreras ambientales para la dispersi & oacute;n hist & oacute;rica de estos organismos que podr & iacute;an haber impulsado la diferenciaci & oacute;n entre estos grupos regionales. Evaluamos cuatro barreras hipot & eacute;ticas en tres per & iacute;odos de tiempo para determinar su posible efecto hist & oacute;rico. Encontramos una alta divergencia ecol & oacute;gica entre las poblaciones de tigrinas del noreste de Brazil y las tigrinas del norte de los andes y centroamericanas. Otros grupos dentro del complejo L. tigrinus son menos divergentes. Adem & aacute;s, las tigrinas del Escudo Guayan & eacute;s, donde se encuentra la localidad tipo de la especie, parece ser ecol & oacute;gicamente similar a las poblaciones del noreste de Brasil, mientras que tambi & eacute;n muestra cierta superposici & oacute;n con las poblaciones andinas. El centro de Panam & aacute;, los Llanos de Colombia y Venezuela y la regi & oacute;n amaz & oacute;nica fueron identificados como barreras hist & oacute;ricas para la dispersi & oacute;n de tigrinas en todos los per & iacute;odos de tiempo. Las barreras hist & oacute;ricas inferidas y la divergencia ecol & oacute;gica observada en este estudio contribuyen a la inferencia de la diferenciaci & oacute;n evolutiva entre los grupos geogr & aacute;ficos que comprenden el complejo L. tigrinus, revelando & aacute;reas de baja idoneidad para el h & aacute;bitat que probablemente han contribuido a la divergencia entre estas poblaciones regionales.

Montane cloud forests are highly threatened ecosystems that are vulnerable to climate change. These complex habitats harbor many species that suffer the negative consequences of this global phenomenon, such as shifts in their distribution and habitat use. The Central American clouded oncilla (Leopardus pardinoides oncilla) is the smallest and most endangered wild cat in Mesoamerica and is primarily reported in cloud forests throughout its distribution. The species is poorly understood, with no studies conducted in Central America assessing its habitat preferences. To bridge this knowledge gap, we sampled two mountain ranges in Costa Rica with camera traps and conducted an occupancy analysis to understand the anthropogenic and environmental features that influence oncilla habitat use within them. Additionally, we conducted spatial predictions of habitat use across its northern and southern range in Costa Rica to identify priority conservation areas for the species. We found that Central American clouded oncilla habitat use is driven primarily by environmental factors. Our results showed that oncillas select habitats with denser tree cover at high elevations, closer to permanent water sources, which may provide them with high prey density and a favorable habitat structure for their survival. Spatial predictions identified two main regions as conservation priority areas where threat mitigation efforts and monitoring should be implemented: the Caribbean slope of the Talamanca mountains, and the Arenal-Monteverde forest complex. The occupancy modeling approach turned out to be very useful to assess the spatial associations of the species with the environment and mapping the conservation priority areas. Future research and mitigation actions should focus on potential threats that could negatively impact Central American clouded oncilla populations and habitat use, including the role of mesopredators and feral species.

Recently, the tiger-cat species complex was split into Leopardus tigrinus and Leopardus guttulus, along with other proposed schemes. We performed a detailed analysis integrating ecological modeling, biogeography, and phenotype of the four originally recognized subspecies—tigrinus, oncilla, pardinoides, guttulus—and presented a new multidimensional niche depiction of the species. Species distribution models used > 1400 records from museums and photographs, all checked for species accuracy. Morphological data were obtained from institutional/personal archives. Spotting patterns were established by integrating museum and photographic/camera-trap records. Principal component analysis showed three clearly distinct groups, with the Central American specimens (oncilla) clustering entirely within those of the Andes, namely the pardinoides group of the cloud forests of the southern Central-American and Andean mountain chains (clouded tiger-cat); the tigrinus group of the savannas of the Guiana Shield and central/northeastern Brazil (savanna tiger-cat); and the guttulus group in the lowland forests of the Atlantic Forest domain (Atlantic Forest tiger-cat). This scheme is supported by recent genetic analyses. All species displayed different spotting patterns, with some significant differences in body measurements/proportions. The new distribution presented alarming reductions from the historic range of − 50.4% to − 68.2%. This multidimensional approach revealed a new species of the elusive and threatened tiger-cat complex.

In 1992, an evolutionary model for the endogenous regulation of parasite-defense grooming was first proposed for African antelope by Ben and Lynette Hart. Known as the programmed grooming model, it hypothesized that a central control mechanism periodically evokes grooming so as to remove ectoparasites before they blood feed. The programmed grooming model contrasts with a stimulus-driven mechanism, in which grooming is stimulated by direct peripheral irritation from ectoparasite bites. In the 30+ years since the seminal 1992 paper, 26 studies have provided robust support for the programmed grooming model in ungulate hosts and ticks. In addition, multiple studies from unaffiliated investigators have evaluated the predictions of the model in different host systems (including rodents and primates) and in a variety of other ectoparasites (fleas, lice, and keds). I conducted a tricennial review of these studies to assess the current evidence and arrived at the following three conclusions: (1) tests of the programmed grooming predictions should use a similar methodology to the well-established protocol, so that the results are comparable and can be properly assessed; (2) the predictions used to test the model should be tailored to the biology of the host taxa under investigation; and (3) the predictions should likewise be tailored to the biology of the ectoparasites involved, bearing in mind that grooming has varying degrees of effectiveness, depending on the parasite. Further research is warranted to enhance our understanding of the role of grooming in maintaining the health of wild animals in the face of parasite attacks.

Corridors are essential tools for promoting biodiversity resilience under climate change. However, corridor design studies are often conducted at spatial scales too coarse to guide implementation by local conservation practitioners. We mapped potential climate-resilient corridors linking lowland to highland protected areas within a highly biodiverse but fragmented landscape of southwestern Costa Rica (6311 km2) 2 ) using least cost path and circuit theory approaches at high spatial resolution (10 m). We then applied an extensive camera trap dataset of medium-large vertebrates to examine corridor functionality. Although least cost paths (n n = 40) were predominantly forested (median = 76 %, range = 57-82 %) and somewhat protected (median = 31 %, range = 3-55 %), they were also highly fragmented. Least cost paths from lowland to highland protected areas traversed medians of 252 forest patches (range = 162-328), 11,186 agriculture patches (range = 822-1,771), and 106 roads (range = 50-252), translating to 2 forest patches, 11 agriculture patches, and 1 road crossed every kilometer. Circuit analyses identified many high-connectivity areas outside of protected areas, including but not limited to least cost paths, but these high-connectivity areas were mostly small forest fragments. Nonetheless, capture rates for medium-to-large mammals at camera traps indicated that many species are currently unlikely to use unprotected, fragmented areas thought to be important for connectivity. In other words, additional conservation and restoration are necessary to establish functional corridors within the landscape. More broadly, this study exemplifies an approach to bridging the gap between regional-scale connectivity analyses and the needs of local practitioners by identifying locations that could be targeted for conservation or restoration within multi-use tropical landscapes.

Although Central America is one of the most biologically diverse regions in the world, booming road construction is driving roadkill mortality that threatens to alter the demography, genetic diversity, and viability of wild mammalian populations. Costa Rica has the highest road density in Central America, but the effectiveness of wildlife crossings in mitigating roadkill mortality has not been assessed with controlled experimental studies. Hacienda Baru National Wildlife Refuge is located along a critical biological corridor bisected by one of the busiest highways in the country. The first wildlife underpasses in Costa Rica were built here in 2010 as part of the expansion of Route 34 and subsequently documented by camera-trap and roadkill surveys. Using a control-impact design, we demonstrate a considerable reduction in wildlife mortality in the presence of the crossing structures compared with controls, with the underpasses and overpasses eventually used by 21 mammalian species. Some species made use of the structures right away, while others took over a year to learn to use them. This is the first controlled study in Central America to document the effectiveness of wildlife crossings and provides evidence that well-designed mitigation structures can contribute to wildlife-friendly roadways.

Introducción: La persistencia de los polimorfismos del color del pelaje, como la coexistencia del color del pelaje melánico (negro) y el "tipo salvaje" (manchado), es un enigma evolutivo. Objetivo: Probamos las predicciones de la Regla de Gloger y la hipótesis de la Segregación Temporal que proponen que los individuos melánicos (a) ocurrirán con mayor frecuencia en el bosque tropical cerrado que en el hábitat abierto debido a las ventajas del camuflaje y la termorregulación, y (b) serán más activos durante las épocas más brillantes del ciclo circadiano y lunar porque la pigmentación negra es críptica bajo una iluminación brillante. Métodos: Con base en 10 años de registros de cámaras trampas de jaguar y tigrillo de un denso bosque tropical en Costa Rica, comparamos la actividad y la abundancia relativa de formas no melánicas (rosetones o manchados) versus formas melánicas. Resultados: El 25% de los registros de jaguares en bosques densos fueron melánicos en comparación con el promedio global del 10% en hábitats abiertos y cerrados; el 32% de los registros de tigrillo fueron melánicos en comparación con el 18% en general en Brasil. El análisis de superposición indicó que los jaguares melánicos eran más activos durante las horas del día en comparación con los jaguares no melánicos, que eran más nocturnos y crepusculares. Asimismo, el tigrillo melánico era más diurno que el tigrillo no melánico. El tigrillo melánico también fue más activo durante la luna llena, mientras que el tigrillo no melánico fue menos activo. Conclusión: Estos resultados implican que los jaguares y tigrillos melánicos disfrutan de los beneficios adaptativos de un camuflaje superior cuando habitan en un bosque denso y acumulan una ventaja de aptitud cuando cazan en condiciones de iluminación más brillante. Si es cierto, la selección natural aseguraría que los individuos melánicos persistan cuando se retiene el bosque denso, pero pueden verse amenazados por la deforestación y la presencia humana acelerada.

In most polygynous species, males compete for access to females using agonistic interactions to establish dominance hierarchies. Typically, larger and stronger males become more dominant and thus gain higher mating and reproductive success over subordinate males. However, there is an inherent trade-off between time and energy invested in dominance interactions versus courtship and mating activities. Individuals may overcome this trade-off by selectively engaging in more effective mating tactics. North American bison (Bison bison) are a species of conservation concern that exhibit female-defense polygyny with two predominant mating tactics: (1) tending individual females; or (2) challenging tending males as a satellite and then mating opportunistically. Here, we use social network analysis to examine the relationship between position in the agonistic interaction network of bison males and their mating, reproductive success, and reproductive tactics and effort. To assess the potential for social network analysis to generate new insights, we compare male (node) centrality in the interaction network with traditional David's score and Elo-rating dominance rankings. Local and global node centrality and dominance rankings were positively associated with prime-aged, heavy males with the most mating success and offspring sired. These males invested more effort in the "tending" tactic versus the "satellite" tactic, and they tended more females for longer periods during peak rut, when most females were receptive. By engaging in the most effective mating tactic, dominant males may mitigate the trade-off between allocating time and energy to agonistic interactions that establish dominance, versus courtship and mating. While less dominant males participated more in the alternative mating tactic, network analysis demonstrated that they were still important to the interaction network on both a local and global scale.

Introducción: La Cordillera de Talamanca en el sureste de Costa Rica, es una región prioritaria para la conservación, posee ecosistemas y especies poco conocidas. El estudio de mamíferos silvestres permite comprender la estructura y estado de conservación de los bosques tropicales: uno de los ecosistemas más diversos del planeta. Objetivo: Evaluar la riqueza, abundancia relativa y patrones de actividad de los mamíferos terrestres medianos y grandes en el Parque Internacional de La Amistad y el Corredor Biológico el Quetzal Tres Colinas. Métodos: Entre el 12 de julio del 2018 al 18 de abril del 2021, instalamos 18 estaciones de fototrampeo, cada una conformada por una cámara trampa y un atrayente olfativo. Resultados: Con un esfuerzo de muestreo de 15 335 días cámara trampa, obtuvimos 36 667 registros en los cuales detectamos 27 especies de mamíferos silvestres medianos y grandes; todas están en alguna categoría de riesgo nacional o internacional. Sciurus granatensis, Tapirus bairdii, Sylvilagus dicei y Mazama temama mostraron la distribución más amplia y la mayor abundancia relativa. Ateles geoffroyi, Cebus imitator y Microsciurus alfari tuvieron la menor abundancia y la distribución más restringida. Registramos cinco especies diurnas, seis nocturnas-crepusculares y 14 catemerales. Las especies únicas las detectamos en los pisos altitudinales Subalpino, Premontano y Montano bajo, los dos últimos registraron la mayor riqueza. Ocho especies mostraron fobia lunar, seis mostraron filia lunar y seis no mostraron afinidad al brillo lunar. Conclusión: Estas áreas protegen importantes poblaciones premontanas a subalpinas de mamíferos terrestres medianos y grandes, muchos catemerales o con fobia a la luna, y deben seguir siendo monitoreadas.

Introducción: Los cambios temporales de nicho pueden amoldar las interacciones predador-presa al permitir a la presa evadir los predadores, mejorar la eficacia de la alimentación y reducir la competición entre predadores. Además de los patrones de actividad circadianos, el ciclo lunar mensual puede influye en los patrones de actividad nocturna de los mamíferos. Objetivo: Mediante muestreos con cámaras trampa en sitios de la pendiente del Pacífico y la Cordillera de Talamanca, investigamos los patrones de actividad circadiana (día y noche) y nocturna durante las fases de la luna del jaguar (Panthera onca) y puma (Puma concolor). Métodos: Investigamos la superposición y segregación temporal entre pares de cada predador y sus presas primarias, y entre sus competidores utilizando análisis de superposición, estadísticas circulares y abundancia relativa, teniendo en cuenta diferencias de hábitat, estaciones, y de impacto humano entre los sitios. Resultados: Nuestros resultados respaldaron la existencia de una separación temporal de nicho entre las dos especies de predadores, aunque ambos fueron clasificados como catemerales, el jaguar era principalmente diurno, mientras que el puma era principalmente nocturno. Descubrimos que el jaguar y el puma practican distintos patrones de actividad nocturna durante las fases de la luna, con el jaguar exhibiendo un aumento dramático en la actividad durante la luna llena y el puma manteniendo un nivel de actividad más consistente a través de las fases lunares. Sin embargo, durante la luna llena, ambas especies fueron más activas durante la noche y menos activas durante el día, lo que sugiere que practican un cambio de nicho temporal para aprovechar las actividades de caza durante la iluminación lunar más brillante de cada mes. Discutimos las presas primarias predichas y las especies competidoras. Conclusión: Concluimos que el jaguar y el puma exhiben una separación de nicho significativa en actividad circadiana y lunar. A través de estos distintos patrones de actividad temporal, el jaguar y el puma pueden explotar una base de presas ligeramente diferente a pesar de su tamaño similar.

Temporal niche shifts can shape predator–prey interactions by enabling predator avoidance, enhancing feeding success, and reducing competition among predators. Using a community-based conservation approach, we investigated temporal niche partitioning of mammalian predators and prey across 12 long-term camera trap surveys in the Pacific slope and Talamanca Cordillera of Costa Rica. Temporal overlap and segregation were investigated between predator–prey and predator–predator pairs using overlap analysis, circular statistics, and relative abundance after accounting for differences in habitat, season, and human impact among sites. We made the assumption that predators select abundant prey and adjust their activity to maximize their temporal overlap, thus we predicted that abundant prey with high overlap would be preferred prey species for that predator. We also predicted that similar-sized pairs of predator species with the greatest potential for competitive interactions would have the highest temporal segregation. Our results supported the existence of temporal niche separation among the eight species of predators—the smaller Leopardus felids (ocelot, margay, oncilla) were primarily nocturnal, the largest felids (jaguar and puma) and coyote were cathemeral, and the smaller jaguarundi and tayra were mostly diurnal. Most prey species (67%) were primarily nocturnal versus diurnal or cathemeral (33%). Hierarchical clustering identified relationships among species with the most similar activity patterns. We discuss the primary prey and competitor species predicted for each of the eight predators. Contrary to our prediction, the activity pattern of similar-sized intraguild competitors overlapped more than dissimilar-sized competitors, suggesting that similar-sized predators are hunting the same prey at the same time. From this we conclude that prey availability is more important than competition in determining circadian activity patterns of Neotropical predators. Our results indicate the presence of a delicate balance of tropical food webs that may be disrupted by overhunting, leading to a depauperate community consisting of ubiquitous generalists and endangered specialists. With Central America a hotspot for hunting-induced “empty forests,” community-based conservation approaches may offer the best road to reduce illegal hunting and maintain the biodiversity and community structure of tropical forest systems.

The persistence of coat color polymorphisms-such as the coexistence of melanistic and "wild-type" coat color-is an ongoing evolutionary puzzle. We tested the predictions of Gloger's rule and the Temporal Segregation hypothesis that propose that melanistic individuals will (a) occur more frequently in closed tropical forest versus open habitat due to camouflage and thermoregulation advantages and (b) be more active during brighter times of the circadian and lunar cycle because black pigmentation is cryptic under bright illumination. Based on 10 years of camera trap records of jaguar and oncilla from dense tropical forest in Costa Rica, we compared activity and relative abundance of non-melanistic wild-type morphs (rosetted or spotted) versus melanistic morphs. Twenty-five percent of jaguar records in dense forest were melanistic compared with the global average of 10% in both open and closed habitats; 32% of oncilla records were melanistic compared with 18% overall in Brazil. Overlap analysis indicated that melanistic jaguars were more active during daylight hours compared with non-melanistic jaguars, which were more nocturnal and crepuscular. Likewise, melanistic oncillas were significantly more diurnal than non-melanistic oncillas; melanistic oncillas were also more active during full moon, while non-melanistic oncillas were less active. These results imply that melanistic jaguar and oncilla enjoy the adaptive benefits of superior camouflage when inhabiting dense forest and accrue a fitness advantage when hunting during conditions of brighter illumination. If true, natural selection would ensure that melanistic individuals persist when dense forest is retained but may be threatened by deforestation and accelerating human presence.

An increasing body of evidence indicates that moonlight influences the nocturnal activity patterns of tropical mammals, both predators and prey. One explanation is that brighter moonlight is associated with increased risk of predation (Predation Risk hypothesis), but it has also been proposed that nocturnal activity may be influenced by the sensory ecology of a species, with species that rely on visual detection of food and danger predicted to increase their activity during bright moonlight, while species relying on non-visual senses should decrease activity (Visual Acuity hypothesis). Lack of an objective measure of "visual acuity" has made this second hypothesis difficult to test, therefore we employed a novel approach to better understand the role of lunar illumination in driving activity patterns by using the tapetum lucidum as a proxy for "night vision" acuity. To test the alternative predictions, we analyzed a large dataset from our long-term camera trap study in Costa Rica using activity overlap, relative abundance, and circular statistical techniques. Mixed models explored the influence of illumination factors (moonrise/set, cloud cover, season) and night vision acuity (tapetum type) on nocturnal and lunar phase-related activity patterns. Our results support the underlying assumptions of the predation risk and visual acuity models, but indicate that neither can fully predict lunar-related activity patterns. With diurnal human "super predators" forcing a global increase in activity during the night by mammals, our findings can contribute to a better understanding of nocturnal activity patterns and the development of conservation approaches to mitigate forced temporal niche shifts.

Bush dogs (Speothos venaticus) are a small, wide-ranging neotropical pack-hunting canid whose ecology is relatively poorly known. Here, we document new, repeated observations of bush dog groups in east-central (Barbilla National Park) and south-eastern (La Amistad International Park) Costa Rica that suggest either that their recent or historic range has been underestimated, or that their potential range in Central America may have recently expanded and could now include not only borderlands with Panama but perhaps a substantial portion of the Talamanca Mountains up to 120 km to the north-northwest and at elevations up to 2,119 m. In light of their inherently low density, documenting the current and future distribution of bush dogs in Central America will be challenging.

Grooming is an important behavioral defense against tick infestation for ungulates. The 'programmed grooming model' explains the endogenous regulation of tick-defense grooming and predicts different inter- and intra-specific grooming patterns owing to the body size principle. Here, we studied the summer grooming behaviors of two sympatric Tibetan ungulates, to explore whether or not body size principle works inter- and intra-specifically. The ungulates were sexually and body-size dimorphic Tibetan antelopes (Pantholops hodgsonii) with body weight of c. 33 kg and sexually dimorphic but body-size monomorphic Tibetan gazelle (Procapra picticaudata) with body weight of c. 14 kg. Group size was also included in our negative binominal regression model to determine whether or not the ungulates groomed more or less with the increasing group size. Results showed that large Tibetan antelopes groomed much less than small Tibetan gazelles inter-specifically. Intra-specifically, sex-age significantly affects the grooming rate of Tibetan antelopes. The largest adult males groomed the least, whereas the smallest fawns groomed the most. However, this sex-age effect is not found in Tibetan gazelle: males and females groomed similarly. These findings indicate that body size principle is fully supported inter- and intra-specifically. Positive group size effect on grooming is observed in Tibetan gazelle, suggesting that released vigilance time from group size effect is probably transferred to grooming. From a conservation point of view, we suggest further studies on the testosterone effect on grooming patterns during the rut as well as on tick biology on the plateau.

Accurate measures of fitness are important for both basic research on sexual selection and applied conservation actions to promote genetic diversity. For polygynous mammals, good estimates of male reproductive success are often critically important, but especially difficult to obtain. Because the genetic contribution of males is impossible to directly measure in the field, investigators have developed surrogate measures of fitness based on behavioral observations. Such measures are founded on the assumption that observed mating success can reliably predict reproductive success, yet only a few studies have been in a position to validate the accuracy of this assumption. We studied the bison herd at Fort Niobrara National Wildlife Refuge for 8 years, conducting intensive behavioral observations on breeding behavior during the rut (2003-2009) and collecting tissue samples of calves born the following year (2004-2010) for genetic paternity analysis. Our results reveal 2 major trends also observed in other studies: Estimates of mating success were positively correlated with reproductive success when we pooled the entire herd across age classes or years. However, copulatory success did a poor job of predicting the actual number of offspring sired by individual males. For example, 44% of observed matings did not result in the birth of offspring, and 60% of the copulations that did produce a calf did not accurately predict the sire bull. Generalized linear mixed model analysis revealed that observation of mating by a given bull in itself had no predictive power regarding likelihood of paternity, whereas total copulations per season, dominance status, and age of bull or dam significantly influenced the probability of siring offspring. Although use of behavioral data was unable to predict the sire for particular cows, it did give insights into patterns of reproductive success that use of genetic data alone could not provide, such as the role of alternate mating strategies and sperm competition for male reproductive success. We conclude that both behavioral and genetic measures of fitness are needed to understand sexual selection and meet the challenges faced by species of conservation concern.

Relaxed selection following extirpation of predators or as a consequence of captive breeding may result in the loss of adaptive antipredator behavior. We propose that it is equally possible for relaxed selection to result in the loss or reduced effectiveness of parasite-defense behaviors such as grooming. In both cases, the reintroduction of captive-bred animals into a predator- or parasite-rich area could have disastrous consequences for the survival of the population. Tick infestation is a powerful force for the evolution of adaptive tick-defense grooming behavior in the wild. The regulation of anti-tick grooming has been well-studied in ungulates and consists of endogenous and exogenous mechanisms, corresponding to the programmed and stimulus-driven grooming models. These models predict that (1) smaller animals will groom more frequently than larger ones, (2) breeding males will groom less than females, (3) animals will groom more during the high-tick season, and (4) animals will groom more in tick-rich vs. tick-sparse habitat. We studied the grooming behavior of Pere David's deer (Elaphurus davidianus), which has experienced genetic bottlenecks and possible relaxed selection as a result of hundreds of years in captivity and was recently reintroduced into the wild in China. Our results indicate that most but not all patterns of adaptive anti-tick grooming behavior have been retained, indicating that some aspects of parasite defense have not undergone relaxed selection even after many years of captivity. Nonetheless, we propose that plans to reintroduce captive-bred animals should take into consideration the historical tick exposure and present grooming behavior of the species in selecting suitable habitat for reintroduction. (C) 2014 Elsevier Ltd. All rights reserved.

Source-filter theory provides a framework to interpret the acoustic structure of vertebrate vocalizations in relation to biophysical production, and it predicts that specific acoustic parameters can encode information about callers. Because formant frequencies are determined by vocal tract dimensions, with longer vocal tracts producing lower formants, they can be reliable indicators of body size, as well as other important traits. In polygynous species, reliable acoustic cues to fitness-related traits are expected to be under strong sexual selection pressure through male competition and/or female choice. This study investigates whether formant frequencies of male North American bison bellow vocalizations encode information about fitness-related caller attributes. Bison exhibit male-dominance female-defence polygyny, with dominance displays involving bellows. We hypothesized that physical attributes (mass, age) would predict formants and that formants would in turn predict quality indices (dominance, copulations, offspring sired). Our results showed that heavier bulls produced lower formants and that lower formants predicted higher mating success (copulations), even when controlling for mass. Given positive associations between mating success, dominance and reproductive success (offspring sired) in bison, we conclude that bellows with lower formants reflect greater fitness in bulls. We discuss the importance of reliable acoustic cues to size and quality indices in sexual selection contexts. (C) 2012 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Sound amplitude (measured as sound pressure level) is an acoustical parameter that has received little attention within communication research, especially in mammals. Although difficult to measure in the field, amplitude is a potentially important parameter of sexually selected signals. In North American plains bison, Bison bison, 'bellows' are low, guttural vocalizations made by bulls during the breeding season in the context of male-male contests. It has been hypothesized that bison use bellow amplitude to assess males during male-male competition or female mate choice. In this study, we tested the hypothesis that amplitude is significantly related to measures of bull competitive ability (quality, condition and motivation), and thus, could function as a sexually selected signal. During peak rut over 2 years, courtship and threat behaviours were recorded daily. During observation sessions, bellow amplitude was measured as peak sound pressure levels using a sound level meter. Subsequent genetic parentage analysis determined offspring sired by males. Based on aspects of signalling and game theory, we predicted positive associations between amplitude and mating and reproductive success, dominance, physical condition, motivation to retain females, age and weight. Our results supported a positive association between amplitude and both physical condition and motivation. Conversely, the results showed a negative association between amplitude and quality, as measured by mating and reproductive success. Supporting evidence and alternative hypotheses for these results are explored. Our findings provide support for the notion that bellow amplitude could be used as a sexually selected signal to assess rival males during male-male competition. (C) 2008 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.