Birth Seasonality in Alouatta caraya in Northern Argentina

Given appropriate ecological and social conditions, natural selection should favor individuals that can concentrate their reproductive events to a particular time of the year that offers high opportunities for infant survivorship. Previous studies on births in Alouatta caraya in Northern Argentina revealed the existence of a peak during the dry season—a period with scarcity of food resources—in mainland gallery forest (G. E. Zunino, Extra 133: 1–10, 1996). The time of conception and the period of independence of the offspring are positively correlated with precipitation, temperature and availability of food. Offspring became independent from their mothers when the availability of resources was high, and conception coincided with the peak of fruit production. Our goal was to examine patterns of birth seasonality in Alouatta caraya in flooded forest on an island in Northern Argentina for comparison with the mainland population. Both sites are at similar latitudes, but differ in forest type. The results indicate that the availability of new and mature leaves is more consistent throughout the year in the flooded forest (p<0.05); however, there was no difference in the availability of fleshy fruits between sites (p>0.05). The pattern of births differed between the gallery forest and the flooded forest (2-way Anova, p<0.001). In the flooded forest births occurred throughout the year, which supports the contentions that howlers do not have a fixed birth season and that the observed variation in the timing of births appears to represent a facultative behavioral response to changes in food availability.     

Habitat fragmentation and population size of the black and gold howler monkey (Alouatta caraya) in a semideciduous forest in Northern Argentina

A population of black and gold howler monkeys (Alouatta caraya) living near the southern limit of its distribution in a semideciduous forest located in northern Argentina was studied in 2003 to evaluate the possible effects of habitat fragmentation - owing to logging - on its density and social organization within it. Aerial photographs taken in 1982, 1992, and 2001 were used to compare maps of vegetation. These maps were used to evaluate changes in the area covered by forest fragments. From March to June 2003, 10-day monthly surveys of howlers were made in each fragment. A total of 232 individual howlers were counted, belonging to 34 groups plus a solitary adult female. Groups ranged from 2 to 19 individuals (mean = 6.82, SD = 4.23), and 21% of the groups contained more than one adult male. Adults accounted for 55% of the individuals, immatures for 45%, and infants represented 13% of the total. Data obtained were compared with information available for the same population for 1982 and 1995. Results revealed no significant changes in the area of fragments, the crude and ecological density of howlers, and group composition. Group sizes and group composition of howlers suggest that the population remained stable over the past 22 years. The density, number of groups, and individuals appears not to be affected by fragmentation and logging, but crude density was low compared with other less-disturbed habitats. The status of the population remains uncertain owing to isolation, and because there are no protected areas to ensure its stability for the future.     

Incipient colonisation of Lutzomyia longipalpis in the city of Resistencia,province of Chaco,Argentina (2010-2012)

Lutzomyia longipalpis was recorded for the first time in Argentina in 2004, in the province of Formosa. In the following years, the vector spread to the south and west in the country and was recorded in the province of Chaco in 2010. From November 2010-May 2012, captures of Phlebotominae were made in the city of Resistencia and its surroundings, to monitor the spread and possible colonisation of Lu. longipalpis in the province of Chaco. In this monitoring, Lu. longipalpis was absent in urban sampling sites and its presence was restricted to Barrio de los Pescadores. This suggests that the incipient colonisation observed in 2010 was not followed by continuous installation of vector populations and expansion of their spatial distribution as in other urban centres of Argentina.     

Post‐fire recovery occurs overwhelmingly by resprouting in the Chaco Serrano forest of Central Argentina

In fire‐prone landscapes, differences in post‐fire regeneration by resprouting between species or sites could be far more important in explaining vegetation physiognomy and composition than seed regeneration. This is the first study exploring the relative contribution of tree resprouts and seeds to post‐fire crown volume in the Chaco Serrano forest of South America. Additionally, we compare the resprouting response among species and quantify post‐fire changes in tree composition among sites. We established 290 permanent plots distributed in three sites affected by wildfires in 2005. For all tree species in all plots we recorded survival of every individual 1 year after the fire; at the plot level, we recorded the above‐ground tree volume before and 3 years after the fire. Resprouting from the base was the main resprouting type. Survival varied between species from 73% to 100% for native species and from 7% to 100% for non‐natives. Before the fire, crown volume was similar in the three sites, and was completely lost after the fire in 92% of the plots. Three years after the fire, between 8% and 58% of crown volume was recovered. The ratio of crown recovery because of resprouts and seedlings was 1562:1. Tree composition exhibited few changes because of the high post‐fire survival of most native species. We conclude that in the semiarid Chaco Serrano ecosystem tree species regenerate mainly by resprouting. This regeneration mode should be taken into account to better understand post‐fire successional pathways of these forests, their management and the restoration of burnt forest areas.     

Infant hybrids in a newly formed mixed-species group of howler monkeys (Alouatta guariba clamitans and Alouatta caraya) in northeastern Argentina

Natural hybridisation between species has been reported in several primate taxa. In the Neotropics, there is increasing evidence of this phenomenon in howler monkeys (genus Alouatta) in contact zones between species. We describe the first known case of formation of a mixed-species group, and two cases of putative infant hybrids between the brown howler (Alouatta guariba clamitans) and the black howler (A. caraya) in Misiones, Argentina. For 2 years, we followed a group consisting of one adult male and two adult female brown howlers and one adult female black howler. The adult female black howler was observed to copulate twice with brown howler males, and never with black howler males. In December 2006, this female was carrying an infant with a hybrid morphotype. This infant died at approximately 1.5 months of age. In November 2007, the same female had another putative hybrid newborn. This infant male died together with all members of his group during a yellow fever outbreak in early 2008. The lower frequency of mixed-species groups and hybrids at our site compared with other contact zones reported in the literature, suggests that the incidence of natural hybridisation between howler species differs depending on local factors such as population demography and landscape fragmentation.     

Phytochemical and mineral components of foods consumed by black howler monkeys (Alouatta pigra) at two sites in Belize

We analyzed the chemical composition of the diets of eight groups of free‐ranging black howler monkeys (Alouatta pigra) in Belize, Central America. The study groups were located in two different forests: the Community Baboon Sanctuary (CBS) and the Cockscomb Basin Wildlife Sanctuary (CBWS). Two of the study groups were translocated from the CBS to CBWS 3 months into the study, and we compared the diets of groups in the two forests. Young and mature leaves, fruits, flowers, and fig samples (n = 144) were analyzed for water content, crude and available protein, fiber, simple sugars, and minerals. Statistically significant differences were found among the plant parts in all measures except acid‐detergent fiber. Dietary foliage in CBS was higher in water content and protein but lower in simple sugars than dietary foliage in CBWS. We suggest that changes in the selection of plant parts by primates may be related to differences in the nutritional content of those parts. These data may be useful in developing optimal diets for captive howler monkeys. Zoo Biol 19:95–109, 2000. © 2000 Wiley‐Liss, Inc.     

Nutritional status of free‐ranging Mexican howler monkeys (Alouatta palliata mexicana) in Veracruz,Mexico: Serum chemistry; lipoprotein profile; vitamins D,A, and E; carotenoids; and minerals

The purpose of this work was to measure important nutritional status parameters for a group of free‐ranging Mexican mantled howler monkeys (A. palliata mexicana) and compare those data to published data for primates. The nutritional status of six free‐ranging Mexican mantled howler monkeys was examined using biochemical analysis. Blood samples were analyzed for serum chemistry; lipids; vitamins D, A, and E; carotenoids; and minerals. Serum chemistries were somewhat different from published values, but did not indicate clear abnormalities. Circulating lipids were not different from those in captive primates. Circulating vitamin D metabolites (83±16.3 for 25(OH)D ng/mL; 563±53.8 for 1,25(OH)₂D pg/mL) were similar to those in wild‐caught tamarins (Saguinus oedipus), lower than some published data for captive Cebidae and Callitrichidae, and higher than for Old World primates. Serum concentrations of retinol (16.5±1.64 μg/dl) were similar to those in captive spider monkeys (Ateles geoffroyi). Retinyl palmitate and retinyl stearate was present in howler samples and may have reflected recent dietary intake. Circulating α‐tocopherol (997±97.6 μg/dl) was similar to published values for other primates. Carotenoid levels in howlers were within the ranges reported for many primates. A significant finding was the presence of cadmium in samples that should be further studied. The number of individuals sampled was limited, and further investigation into the effects of seasonality is needed. However, this information provides new data for howler monkeys and for free‐ranging primates in general. Zoo Biol 22:239–251, 2003. © 2003 Wiley‐Liss, Inc.     

Demographic population structure of black howler monkeys in fragmented and continuous forest in Chiapas,Mexico: Implications for conservation

For wild primates, demography studies are increasingly recognized as necessary for assessing the viability of vulnerable populations experiencing rapid environmental change. In particular, anthropogenic changes such as habitat loss and fragmentation can cause ecological and behavioral changes in small, isolated populations, which may, over time, alter population density and demographic structure (age/sex classes and group composition) in fragment populations relative to continuous forest populations. We compared our study population of Endangered black howler monkeys (Alouatta pigra) in 34 forest fragments around Palenque National Park (PNP), Mexico (62 groups, 407 individuals), to the adjacent population in PNP, protected primary forest (21 groups, 134 individuals), and to previous research on black howlers in fragments in our study area (18 groups, 115 individuals). We used χ² and Mann–Whitney U tests to address the questions: (a) what is the current black howler demographic population structure in unprotected forest fragments around PNP? (b) How does it compare to PNP's stable, continuous population? (c) How has it changed over time? Compared to the PNP population, the fragment populations showed higher density, a significantly lower proportion of multimale groups, and significantly fewer adult males per group. The population's age/sex structure in the fragmented landscape has been stable over the last 17 years, but differed in a higher proportion of multifemale groups, higher density, and higher patch occupancy in the present. In the context of conservation, some of our results may be positive as they indicate possible population growth over time. However, long-term scarcity of adult males in fragments and associated effects on population demographic structure might be cause for concern, in that it may affect gene flow and genetic diversity. The scarcity of adult males might stem from males experiencing increased mortality while dispersing in the fragmented landscape, whereas females might be becoming more philopatric in fragments.     

Pollen dispersal and genetic variation in an early‐successional forest herb in a peri‐urban forest

In order to conserve forest plant species under the particularly high constraints that represent urban surroundings, it is necessary to identify the key factors for population persistence. This study examined within‐ and between‐population pollen dispersal using fluorescent dye as pollen analogue, and genetic variation and structure using 15 allozyme loci in Centaurium erythraea, an insect‐pollinated, early‐successional forest biennial herb occurring in a peri‐urban forest (Brussels urban zone, Belgium). Dye dispersal showed an exponential decay distribution, with most dye transfers occurring at short distances (<15 m), and only a few long‐distance events (up to 743 m). Flowers of C. erythraea are mainly visited by Syrphids (Diptera) and small bees, which are usually considered as short‐distance pollen dispersers, and occasionally by bumblebees, which are usually longer‐distance pollen dispersers. Small and large dye source populations differed in dye deposition patterns. The populations showed low genetic diversity, high inbreeding coefficients (F_IS) and high genetic differentiation (F_ST), suggesting restricted gene flow, which can be expected for an early‐successional biennial species with a predominantly selfing breeding system and fluctuating population sizes. The positive relationship between recruitment rate and allelic richness and expected heterozygosity, and the absence of significant correlations between genetic variation and population size suggest seedling recruitment from the seed bank, contributing to maintain genetic diversity. Long‐distance dye dispersal events indicate pollinator movements along urban forest path and road verges. These landscape elements might therefore have a potential conservation value by contributing to connectivity of early‐successional species populations located in patchy open habitats.     

Differences in diet and activity pattern between two groups of Alouatta palliata associated with the availability of big trees and fruit of top food taxa

The threat that forest fragmentation and habitat loss presents for several Alouatta taxa requires us to determine the key elements that may promote the persistence of howler monkeys in forest fragments and to evaluate how changes in the availability of these elements may affect their future conservation prospects. In this study we analyzed the relationship between the availability of both big trees of top food taxa (BTTFT) (diameter at breast height>60) and fruit of top food taxa (FrTFT) in the home ranges of two groups of Alouatta palliata mexicana occupying different forest fragments in Los Tuxtlas, Mexico, and their diet and activity pattern. Both study groups preferred big trees for feeding and the group with lower availability of BTTFT in their home range fed from more, smaller food sources. Furthermore, both study groups also increased the number of food sources when their consumption of fruit decreased, and the group with lower availability of FrTFT in their home range fed from more food sources. The increase in the number of food sources used under such conditions, in turn, set up a process of higher foraging effort and lower rest. In summary, our results support other studies that suggest that the availability of big trees and fruit may be two important elements influencing the persistence of howler monkeys in forest fragments. Am. J. Primatol. 71:654–662, 2009. © 2009 Wiley‐Liss, Inc.     

Fruit eating and seed dispersal by howling monkeys (Alouatta palliata) in the tropical rain forest of Los Tuxtlas,Mexico

The frugivory and ranging habits of howling monkeys living in the rain forest of Los Tuxtlas, Veracruz, Mexico, were studied for 5 consecutive years with the aim of investigating the role of seed dispersal agents played by the howling monkeys. The howling monkeys' consumption of fruit occupied half of their feeding time, and 80% of this time was spent feeding on mature fruit. Observations confirmed use of 19 tree species and a preference for a few species of Moraceae and Lauraceae. Fruit exploitation was very seasonal; only two species provided fruit year-round. Home range size was about 60 ha, and animals in the troop (N = 16) showed a day range of 10–893 m. Monthly collection of fecal samples during 2 years indicated that 90% of the seeds (N = 7,928) in the samples belonged to eight tree species and to one liana; the rest belonged to 15 unidentified species of vines. Germination success for the seeds in the feces was about 60% and for control seeds was 35%. Howling monkeys created diverse seed shadows in the vicinity of their leaf and fruit sources, and while they dispersed the seeds of some plant species, they also produced a great deal of fruit and seed waste for others.     

Seasonal variation and natural infection of Lutzomyia antunesi (Diptera: Psychodidae: Phlebotominae), an endemic species in the Orinoquia region of Colombia

Lutzomyia antunesi has been commonly reported in outbreaks of cutaneous leishmaniasis (CL) in the Orinoquia region of Colombia. The bionomics of this species were studied in the municipality of Villavicencio (Meta, Colombia). Sandflies were captured over the course of one week per month for one year in intradomiciliary, peridomiciliary and extradomiciliary housing areas. The captures were performed from 06:00 pm-06:00 am using CDC light traps and the females were processed for polymerase chain reaction (PCR) to detect Leishmania spp. A total of 22,097 specimens and 19 species were captured of which Lu. antunesi (89%) and Lutzomyia walkeri (5%) were the most abundant. Other species recognised as anthropophilic (Lutzomyia panamensis, Lutzomyia gomezi, Lutzomyia flaviscutellata and Lutzomyia fairtigi) were present in very low abundance (< 2%). Natural infection with Leishmania spp was detected using PCR in Lu. antunesi, Lu. panamensis and Lu. flavicutellata, showing infection rates of 1%, 4.8% and 7.5%, respectively. The present paper provides information on various ecological aspects of Lu. antunesi. An analysis of seasonality shows that this species increases in abundance in the hottest months (December, January and February), directly correlating with the maximum temperature and inversely correlating with precipitation. The natural infection rate is associated with the peaks of highest abundance.     

Vertical distribution of fruit‐feeding butterflies with evidence of sex‐specific differences in a Tanzanian forest

Tropical forests accommodate rich species diversity, particularly among insects. Habitat heterogeneity along the vertical gradient extending from the forest understorey to the tree canopy influences diversity. The vertical distribution of forest insects is poorly understood across Africa, most especially eastern Africa. Food‐baited traps were used to study the vertical stratification of adult fruit‐feeding nymphalid butterflies in Mtai Forest Reserve, north‐eastern Tanzania. Traps were located in the forest canopy and understorey. A total of 277 individuals of 24 species were captured. Species composition differed by trap locations: 33% of the species captured were found in both the canopy and understorey strata; however, significantly more species were captured in the understorey (54%) than canopy (13%). Males were significantly more abundant than females and captured in both strata. A greater proportion of females were captured in the understorey than the canopy. The time of day affected capture rates, with more individuals caught in the afternoon; however, there was no association between the time period and the sex of individuals captured in canopy versus understorey locations. Understanding how the sexes of butterflies vary in understorey versus canopy offers new biological insights into the vertical stratification of insects.     

Climate as a determinant of dung beetle response to native forest replacement by cattle pastures in South America

Anthropogenic disturbance in natural ecosystems reduces the number of species in biological communities and homogenizes their composition across different regions. Climate is one of the main abiotic determinants of species distributions and different factors were proposed as the main climatic drivers. Here we explored the role of regional climate on the local response of dung beetle assemblages to the replacement of native forest by cattle pastures in South America by simultaneously contrasting three climatic hypotheses: energy, seasonality and heterogeneity. We compiled a database by searching published studies comparing dung beetle richness and composition between both native forests and cattle pastures. We calculated the proportional difference in species richness and composition between habitat types. As explanatory variables, we used seven abiotic variables grouped into the three climatic hypotheses. Energy/Productivity: mean annual temperature (°C/year) and total annual precipitation (mm/year). Seasonality: annual thermal amplitude (°C/year), the average coefficient of variation of monthly precipitation and the coefficient of average monthly variation in temperature. Heterogeneity: coefficient of variation of mean annual temperature, coefficient of variation of mean annual precipitation. Using regression analyses and a model selection procedure, we found differences in species richness between native forests and cattle pastures were explained by the coefficient of variation of mean annual precipitation, whereas changes in species composition were explained by total annual precipitation and the coefficient of variation of mean annual precipitation. The response of dung beetle assemblages to livestock grazing in South American forests was associated with precipitation variation. The heterogeneity hypothesis better explained changes in species richness following forest replacement by cattle pastures, while both energy/productivity and heterogeneity hypotheses explained the changes in species composition.     

Seroprevalence of Trypanosoma cruzi and Leishmania mexicana in Free‐Ranging Howler Monkeys in Southeastern Mexico

Natural infection of wild mammals by protozoa parasites is quite common in nature. For Neotropical Primates different infections of parasites that are etiological agent of disease in human have been identified. In particular, infections by Trypanosoma cruzi and Leishmania sp., have been reported for some New World primate species, but there are no reports of infection with these parasites in any primate species in Mexico. A serological study was conducted on two howler monkey species (Alouatta pigra and A. palliata) from the Mexican states of Campeche and Tabasco. A total of 55 serum samples (20 samples from A. pigra, 20 samples from A. palliata, and 15 samples from semifree ranging A. palliata of Los Tuxtlas, Veracruz as negative controls) were analyzed for the detection of immunoglobulin G antibodies against T. cruzi and Leishmania mexicana through enzyme linked immunosorbent assay test, indirect immunofluorescence assay and Western blot. The overall prevalence of antibodies in howler monkeys was 17.5% for T. cruzi and 30% for L. mexicana. Our results also indicate that A. pigra is more susceptible to develop leishmaniasis than A. palliata. Finally, the finding of positive serology in these primates should be given serious consideration for public health, given the potential role of these primate species as wild reservoirs for these diseases and the increasing contact of monkeys with human populations due to habitat loss and fragmentation. Am. J. Primatol. 75:161‐169, 2013. © 2012 Wiley Periodicals, Inc.     

Sparing land for secondary forest regeneration protects more tropical biodiversity than land sharing in cattle farming landscapes

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