Recolonization of Former Range by Endangered Banteng Bos javanicus in Mae Wong National Park, Thailand

Many large ungulate species, including the banteng ( Bos javanicus), are on the verge of extinction. Mae Wong National Park in Thailand was once a haven for banteng due to its abundance of preferred habitat, but the species was extirpated in the 1970s due to logging and hunting, before park designation. Mae Wong is connected with Huai Kha Khaeng Wildlife Sanctuary (HKK), which retains the largest banteng population remaining in Thailand. In 2019, Mae Wong park rangers reported suspected banteng footprints near HKK. We used camera traps to verify the presence of banteng and determine their population structure and activity pattern. We observed at least nine individual bantengs (range 1–7 each month) during the 15-month survey, including three adult males, two adult females, three juveniles, and 1 calf. Solitary males and herds (up to five animals) were observed, reflecting typical social structure. Banteng were detected throughout the survey and across all seasons, suggesting a resident population. Our research confirms the return of banteng to Mae Wong after an absence of over 40 years. The banteng likely dispersed from HKK, emphasizing the importance of landscape connectivity and source sites for recovery of endangered species. Though still small, the Mae Wong population is breeding, which is significant for future population recovery. Protection, community outreach, and habitat management can help secure this population. As banteng is the preferred food of tigers, their recovery will benefit tiger conservation in Mae Wong as well.

Sex Differences in Group Composition and Habitat Use of Iberian Free-Range Pigs

The aim of the present work was to study group size, group composition and habitat use of Iberian pigs along the year when reared outdoor. This consists of a regimen in which animals are reared free range from 2 months of age until at least 14 months of age. In a first stage, animals are supplemented with concentrates, and in a second, called montanera, pigs eat just natural resources in areas with no more than two pigs per hectare. In these systems, males are castrated to avoid boar taint and females spayed to avoid the attraction and mounting by wild boars. The study was carried out in five different farms allocated in the south-west of Spain during 2 consecutive years, from March 2012 to February 2014, under the montanera regimen, and with a total of 995 animals observed (498 males and 497 females). The data were analyzed with SAS by means of general models and proc mixed. Mean group size along the year was of 17 ± 12.9 individuals, but this was significantly lower (P < 0.05) during the montanera (12 ± 0.8) and at midday (13 ± 0.8). Groups were bigger (P < 0.05) when they were more than 50 m from a tree (23 ± 1.8), or <10 m from the shelter (25 ± 1.5), the feeding area (31 ± 3.1) and the water-bath area (25 ± 1.5). Nine percent of the groups were solitary animals, being higher (P = 0.0286) during the montanera (11%) than the rest of the year (8%) and being formed in 68% by males. Males were less involved in mixed groups than were females (75% vs. 91%), especially in spring, where the largest (P < 0.0001) male groups were found. Female groups were less frequent and smaller (P < 0.0001) than were male and mixed groups. In conclusion, although males were castrated at a very young age, they showed a different behavior than females, forming in bachelor groups during the spring and being less involved in mixed groups and with more solitary animals. During the montanera, when animals were feeding on acorns and other natural resources, groups were smaller and closer to the trees, solitary males reaching a maximum percent.

Violent encounters between social units hinder the growth of a high-density mountain gorilla population

Density-dependent processes such as competition for resources, migration, predation, and disease outbreaks limit the growth of natural populations. The analysis of 50 years of mountain gorilla data reveals that social behavior changes observed at high group density may also affect population growth in social species. A sudden increase in social group density observed in 2007 caused a threefold increase in the rate of violent encounters between social units (groups and solitary males). A fivefold increase in the rate of infanticide and seven cases of lethal fights among mature males were subsequently recorded, and the annual subpopulation growth rate declined by half between 2000 and 2017. The increase in infanticide alone explains 57% of this decline. These findings highlight the complex relationship between population density and growth in social species and hold important implications for the management of island populations.

Population Estimation of Proboscis Monkeys in Mangroves at Kuching Wetland National Park, Sarawak

Boat survey on proboscis monkey (Nasalis larvatus) population in Kuching Wetland National Park (KWNP) was conducted to estimate the current population density and population size of this primate. The survey was conducted on September 2015 and January 2016 covering a cumulative distance of 128.91 km of mangrove riverbank. A cumulative total of 158 individuals comprising 19 groups, including one all-male group and three solitary males were recorded throughout the survey. The population density of proboscis monkeys in mangrove forest at KWNP was estimated at 1.63 individuals/km2 or 0.20 groups/km2. Based on the extrapolation of the estimated population density data, the population size of proboscis monkey in mangrove forest at KWNP was estimated to be 82 individuals. Last published report on the estimation of proboscis monkey population in Sarawak was more than 30 years ago. This study was conducted as a part of the efforts to assess the current population status of proboscis monkey in Sarawak. Keywords: Estimation, population density, population size, proboscis monkey

Sexual behavior of the desert locust during intra-and inter-phase interactions

Mating and reproduction behaviors and strategies are fundamental aspects of an organism’s evolutionary and ecological success. In locusts, intra- as well as inter-phase reproductive interactions among gregarious and solitarious locust populations have a major impact on the locust population dynamics. However, practically all previous work on locust sexual behavior has been limited to the gregarious phase. Here we provide a first detailed description of pre-copulatory behavior of solitarious desert locusts. We compare our findings with those of previous reports of pre-copulatory behavior of gregarious locusts, focusing on the behavioral elements that serve in inter-sex signaling and communication. We also studied inter-phase (mixed pairs) reproductive interactions. Solitarious males were found to invest more in pre-copulatory courtship and signaling compared to their gregarious counterparts; and the solitarious females played a comparatively more dominant role in the inter-sex communication. The solitarious females were also less prone to demonstrate the typical rejection-related behavioral patterns displayed by the gregarious females. As a consequence of the particular characteristic behavior of each phase, the most successful among intra- and inter-phase pairs were gregarious males with solitary females. Least successful were solitary males encountered with gregarious females, indicating a strong asymmetry in inter-phase reproductive interactions. We discuss these results in the context of non-random or assortative mating in locust mixed or sympatric solitarious-gregarious populations.

Activity budgets and behavioural synchrony in a wild equid living in a fission-fusion social system

Variation in activity budgets among individuals of different age-sex classes and reproductive status may lead to decreases in behavioural synchrony (i.e., individuals performing the same behaviour at the same time in the same group) in social species. Here, we assessed the costs of behavioural synchrony in terms of time allocated to feeding behaviour among individuals of different age-sex classes and reproductive status in the kiang (Equus kiang), a poorly known wild equid that inhabits the Tibetan Plateau. Our study was conducted in Eastern Ladakh (India), during summer and fall. Our results showed that groups were highly synchronized, and that individuals in groups were particularly synchronized when feeding. Despite a slight sexual dimorphism, males and females had similar activity budgets. Males in groups, however, spent less time feeding than solitary males, and females in groups with foals spent less time feeding and more time standing than females in groups without foals. We suggest that group formation in males and the presence of foals for females incur behavioural costs by lowering their time spent feeding. Because these costs occur at a predictable time of the year, it could be profitable for adult kiangs not to form permanent groups year-round. Individuals with divergent needs might benefit from the loose social system observed in kiangs, which could be a key feature of their adaptation to a highly seasonal environment.

Ecology of the bromeligenous frog Phyllodytes luteolus (Anura, Hylidae) from three restinga remnants across Brazil's coast

In this study, we analyzed diet, sexual dimorphism and bromeliad use in three populations of the hylid frog Phyllodytes luteolus from restinga habitats along the Brazilian coast. We found 13 arthropods categories in 161 stomachs. Ants and termites were the dominant prey items. The similar trophic niche across populations suggests this species has a conservative diet. We found sexual dimorphism regarding body size and jaw width. We recordedP. luteolus in five bromeliad species, but predominantly inAechmeablanchetiana (35.6% of individuals recorded). We recorded solitary individuals in 44% of occupied bromeliads, and never found two males sharing the same bromeliad. The data is suggestive that populations ofP. luteolus has a conservative diet independent of area, with ants and termites the being most relevant prey items. The sexual dimorphism in jaw and the solitary males may suggest that this species have territorial behavior.

Social organization and demography of reintroduced Dorcas gazelle (Gazella dorcas neglecta) in North Ferlo Fauna Reserve, Senegal

As part of a reintroduction project in Senegal, 23 (9.14) captive-born Dorcas gazelles were released into a 440-ha fenced-in area in Katané (North Ferlo Fauna Reserve, Senegal) in March 2009. After 4 years of seasonal monitoring, the gazelles showed progressive adaptation of their behavior to semi-wild living conditions. Breeding gradually became seasonal, and 53.8% of births occurred during the rainy season (July to September). Gazelle group size and composition varied seasonally. Groups were smallest during the dry season (2.29±1.72) and largest at the beginning of the rainy season (4.18±2.73). Social group composition also showed seasonal variation. There were always a larger proportion of solitary males than solitary females and mixed couples were observed throughout the year. All-male groups were found the least. The proportion of adult females with subadults and juveniles decreased during the early rainy season, while mixed adults, subadults and juveniles groups increased during this period. The mortality rate during the first weeks after release was 13%. Four years of monitoring after release, demographic traits of this released population reveal its adaptation from captive to natural-living conditions.

Recovery of the Critically Endangered Hainan gibbonNomascus hainanus

The Critically Endangered Hainan gibbonNomascus hainanusis one of the most threatened primate species and is now found only in the Bawangling National Nature Reserve of Hainan Province, China. We describe changes in population dynamics, and the current number of individuals, based on historical sources and fieldwork during 2002–2013. The population comprises a total of 20 individuals (including six solitary males) in three separate groups. All are confined to an area of c. 16 km2. The current population developed from two groups that comprised a total of 13 individuals in 2002, and has increased slowly since then, with the addition of one new group. Population increase is hindered by the gibbon's unique social structure of one adult male and two adult females, as well as the reproductive age limit in adult females. An imbalance in the sex ratio of offspring may also have hindered population recovery but further investigation of this is required. Our findings indicate that the Hainan gibbon is likely to remain Critically Endangered in the coming decades.

Dietary availability in elderly Portuguese households

ObjectiveTo identify dietary availability and its time trends in elderly Portuguese households.DesignA set of four cross-sectional studies based on the Household Budget Surveys was used. The dietary data were described using the daily per capita availability of food and beverages, energy and selected nutrients (macronutrients, different lipid fractions and simple sugars). Differences between elderly household types and time trends were studied.SettingPortuguese Household Budget Survey data from 1989/1990, 1994/1995, 2000/2001 and 2005/2006.SubjectsHouseholds with members aged ≥65 years were selected and categorized as solitary elderly female, solitary elderly male or couple (composed of one elderly female and one elderly male).ResultsWhile cereals, fats/oils, potatoes and sugar/sugar products decreased, an increase occurred in milk/milk products, fruits, bottled water, fruit/vegetable juices and soft drinks (P<0·05). The highest values for foods and beverages were mostly found in couples, while the lowest ones were from solitary males. Exceptions were observed for cereals, eggs, milk/milk products, vegetables, fruits and non-alcoholic beverages, higher in solitary females; and for sugar/sugar products and alcoholic beverages, higher in solitary males. Over time, total energy and carbohydrates decreased while proteins and saturated fatty acids increased (P<0·001). Lipids increased in solitary males and couples (P<0·05). Simple sugars increased in solitary males but decreased in solitary females and couples (P<0·05).ConclusionsThe increases in fruits and vegetables in solitary females accord with a healthier food pattern, but overall imbalances in the macronutrient profile for all elderly households may imply a decreasing diet quality.