Stingless bees: uses and management by meliponiculturist women in the Chaco region of Bolivia.

BACKGROUND: Stingless bees have a great value as main pollinators of wild flowering and cultivated plants, thus playing a fundamental role in the maintenance of biodiversity and food security in Latin America. Despite their importance, stingless bees face numerous threats causing alarming population declines. Moreover, stingless bees have a great cultural and traditional value, since most products from the hive are used for a wide variety of purposes. A growing number of initiatives are encouraging the breeding of these bees, through training courses and modern management techniques. This study documents the knowledge on stingless bees and their products that meliponiculturists from the Chaco region of Bolivia have, as well as the influence that meliponiculture initiatives have on the management and general knowledge of the bees. METHODS: Local richness and diversity of stingless bees was calculated using Hill numbers. Structured interviews were conducted with 59 meliponiculturists in order to characterize traditional and formal knowledge on stingless bees and meliponiculture. Generalized linear models were applied to assess the influence of training courses on the management of the bees. Also, a relative cultural importance index was calculated for each species. RESULTS: Twelve Meliponini species were identified, and 15 local names were reported with morphological, defensiveness behavior, and nest description. There was no significant difference in the knowledge between different ethnical backgrounds or ages. A significant difference was observed in the use of supplementary feeding and assisted division, but none in the success in racking hives or in pest management, regarding the number or courses taken. The relative cultural importance index recorded 30 specific uses for bee products grouped in four categories, from which 29 were attributed (but not exclusively) to Tetragonisca angustula, making it the most versatile species. CONCLUSIONS: The products of the hive, especially honey, are used for a wide variety of purposes, mostly in medicine. These uses are mostly attributed to just one species, T. angustula, in coincidence with what was taught in meliponiculture training courses by NGOs. The influence of formal knowledge is mostly positive, but it is recommended that other meliponini species are taken into account as well.

Serial Mediation Model of Social Capital Effects over Academic Stress in University Students.

Background: Although several studies have shown that social capital and social support decreases academic stress (AS), there has been lack of atheoretical model to explain how this occurs. This study aims to verify a model that explains the effect of bonding social capital (BSC) over academic stress psychological symptoms (PsyS), considering the multiple sequential mediation of socio-emotional support (SES), self-efficacy (sEffic) and self-esteem (sEstee). Methods: In a transversal study, 150 undergraduate volunteer students were recruited using non-probabilistic purposive sampling. Data were collected using psychological questionnaires and were processed through partial least squares structural equation modeling (PLS-SEM). Results: Goodness of fit of the models (SRMR = 0.056, 0.057,

Pollen Preference Patterns by Tetragonisca angustula (Apidae: Meliponini) in a Boliviano-Tucumano Forest.

Native bees are important pollinators in neotropical forests. Tetragonisca angustula (Latreille) (Apidae: Meliponini) is a stingless bee widely distributed from the south of Mexico to Argentina. We characterized the patterns of preference of T. angustula for pollen in relation to the richness and abundance of plant species in the Tucumano-Boliviano Forest. During two field campaigns in different seasons (winter and spring), six colonies of T. angustula were studied. Pollen from flowers of plant species in the study area (pollen offer) and pot-pollen in each hive (pollen demand) were collected and their plant family of origin identified. Pollen from Asteraceae was more abundant in the winter than in the spring. Pollen of Solanaceae in the winter and Bignoniaceae in the spring were the most selected by the worker bees. Pollen from plants outside the sampling area was also found in the pots; it was mainly from Asteraceae. Tetragonisca angustula workers showed a polylectic foraging behavior, being able to use in a dynamic way the resources that are present in their environment at different times of the year; occasionally, it selected less abundant specific resources likely based on their nutritional value. More studies are needed to evaluate aspects of pollen quality consumed by this bee.

Smoke of Capsicum baccatum L. var. baccatum (Solanaceae) repels nymphs of triatoma infestans (Klug) (Hemiptera: Reduviidae) / Humo de capsicum baccatum L. var. baccatum (Solanaceae) repele las ninfas de Triatoma infestans (Klug) (Hemiptera: Reduviidae)

Control of the Chagas disease vector, Triatoma infestans (Klug) (Hemiptera: Reduviidae) with synthetic pesticides in Bolivia has become increasingly inefficient due to the development of resistance in the insects. In the Chaco region of Bolivia, guaraní populations have approached the problem by fumigating their houses with the smoke of native plants. Through interviews and field work with local guides, the main plant used by the guaraníes was collected and later identified as Capsicum baccatumL. var. baccatum (Solanaceae). In choice bioassays, filter papers exposed to the smoke of the plant repelled nymphs of T. infestans. Activity remained significant after storing the exposed filter papers for 9 days. Chemical analysis of smoke and literature data suggested that capsaicinoids present in the smoke were responsible for the repellent effect. The data presented provide a rationale for the use of C. baccatumvar. baccatumto control the Chagas vector bythe guaraní populations.

El control del vector de la enfermedad de Chagas, Triatoma infestans (Klug) (Hemiptera: Reduviidae) con plaguicidas sintéticos en Bolivia se ha vuelto cada vez más ineficiente debido al desarrollo de resistencias en los insectos. En la región del Chaco de Bolivia, las poblaciones guaraníes han abordado el problema fumigando sus casas con el humo de las plantas nativas. A través de entrevistas y trabajo de campo con guías locales, se recogió la principal planta utilizada por los guaraníes y posteriormente se identificó como Capsicum baccatumL. var. baccatum (Solanaceae). En bioensayos selectos, los papeles de filtro expuestos al humo de la planta repelieron a las ninfas de T. infestans. La actividad siguió siendo significativa después de almacenar los papeles de filtro expuestos durante 9 días. El análisis químico del humo y los datos de la literatura sugieren que los capsaicinoides presentes en el humo eran responsables del efecto repelente. Los datos presentados proporcionan una justificación para el uso de C. baccatum var. baccatum para el control del vector Chagas por las poblaciones guaraníes.

Unraveling the Morphological Variation of Triatoma infestans in the Peridomestic Habitats of Chuquisaca Bolivia: A Geometric Morphometric Approach.

Morphometrics has been used on Triatomines, a well-known phenotypically variable insect, to understand the process of morphological plasticity and infer the changes of this phenomenon. The following research was carried out in two regions of the inter-Andean valleys and two Chaco regions of Chuquisaca-Bolivia. Triatoma infestans adults were collected from the peridomestic (pens and chicken coops) along a geographic gradient in order to evaluate the morphological differentiation between groups and their pattern of sexual shape dimorphism. Geometric morphometric methods were applied on the wings and heads of T. infestans. The main findings include that we proved sexual dimorphism in heads and wings, determined the impact of environmental factors on size and shape and validated the impact of nutrition on head shape variation. These results show that geometric morphometric procedures can be used to provide key insight into the biological adaptation of T. infestans on different biotic (nutrition) and abiotic (environment) conditions, which could serve in understanding and evaluating infestation processes and further vector control programs.

Age-related anomalies of electrocardiograms in patients from areas with differential Seroprevalence of Chagas disease in Southern Bolivia.

INTRODUCTION: Chagas disease currently affects some 6 million people around the world. At the chronic stage, cardiomyopathy occurs in about 20-30% of infested people. Most prevalence studies have focused on young to adult people due to the drastic consequences of acquiring the pathogen and the possibility to cure the disease at this age; the prevalence of this disease, the effect of patients' sex and the consequences to senescent people have been largely neglected. This study looks to characterize the seroprevalence of Chagas disease and its relation with occurrence of electrocardiographic anomalies associated with sex and age, and to compare rural and urban populations in Bolivia. METHODOLOGY: Seroprevalence of Chagas disease was determined in blood samples and electrocardiograms were performed on seropositive individuals. RESULTS: The rural population showed higher seroprevalence than the urban population (92% and 40%, respectively). The proportion of Chagasic cardiac anomalies in seropositive persons was highest in patients of the 50-59 age group (36%) as compared with the 40-49 (8%) and the ≥60 (17%) age groups. CONCLUSIONS: Higher seroprevalence in rural population was attributable to a higher probability to encounter the vector in rural areas. Increased exposure to infection and to development of the disease symptoms together with increased lethality of the disease as patients age explains the age-related Chagasic electrocardiographic anomalies. Since rural and urban populations showed different reactions under Chagas disease and the rural population was mainly of guaraní stock, the genetic and environmental determinants of the results should be further explored.

Leaf vibrations produced by chewing provide a consistent acoustic target for plant recognition of herbivores.

Plant defenses that respond to the threat of herbivory require accurate sensing of the presence of herbivores. Herbivory cues include mechanical damage, elicitors from insect saliva or eggs, and airborne volatiles emitted by wounded plants. Plants can also respond to the leaf vibrations produced by chewing herbivores. However, previous studies of the influence of feeding vibrations on plant defenses have been limited to single species pairs. In this study we test the hypothesis that chewing vibrations differ among herbivore species, both in their acoustic features and in their potential effect on plant defense responses. We first compare the acoustic traits of larval feeding vibrations in ten species from six families of Lepidoptera and one family of Hymenoptera. We then test responses of Arabidopsis thaliana plants to variation among feeding vibrations of different individuals of one species, and to feeding vibrations of two species, including a pierid butterfly and a noctuid moth. All feeding vibrations consisted of repetitive pulses of vibration associated with leaf tissue removal, although chewing rates varied between species and between large and small individuals within species. The frequency spectra of the vibrations generated by leaf feeding were similar across all ten species. Induced increases in anthocyanins in A. thaliana did not differ when plants were played vibrations from different individuals, or vibrations of two species of herbivores with different chewing rates, when amplitude was held constant. These results suggest that feeding vibrations provide a consistent set of cues for plant recognition of herbivores.

Assessment of Shape Variation Patterns in Triatoma infestans (Klug 1834) (Hemiptera: Reduviidae: Triatominae): A First Report in Populations from Bolivia.

The morphological variations of four populations of geographically isolated Triatoma infestans located in the area of inter-Andean valleys and Chaco of Chuquisaca, Bolivia, were evaluated. Fifty-three females and sixty-one males were collected in the peri-domicile and analyzed with geometric morphometrics tools to study the patterns of the head and wing shape variation. The principal component analysis and canonical variate analysis revealed morphological variations between the populations studied, which were then confirmed by the permutation test of the differences between populations using Mahalanobis and Procustes distances. The multivariate regression analysis shows that the centroid size influences the shape of the heads and wings. T. infestans of the inter-Andean valleys are longer in the head and wings compared to the population of the Chaco. We propose that the geometric shape variation may be explained by geographical changes in climatic conditions, peri-domiciliar habitats, food source quality, and the use of insecticides.

Chemical Responses of Nicotiana tabacum (Solanaceae) Induced by Vibrational Signals of a Generalist Herbivore.

Plants are able to sense their environment and respond appropriately to different stimuli. Vibrational signals (VS) are one of the most widespread yet understudied ways of communication between organisms. Recent research into the perception of VS by plants showed that they are ecologically meaningful signals involved in different interactions of plants with biotic and abiotic agents. We studied changes in the concentration of alkaloids in tobacco plants induced by VS produced by Phthorimaea operculella (Lepidoptera: Gelechiidae), a generalist caterpillar that naturally feeds on the plant. We measured the concentration of nicotine, nornicotine, anabasine and anatabine in four treatments applied to 11-weeks old tobacco plant: a) Co = undamaged plants, b) Eq = Playback equipment attached to the plant without VS, c) Ca = Plants attacked by P. operculella herbivory and d) Pl = playback of VS of P. operculella feeding on tobacco. We found that nicotine, the most abundant alkaloid, increased more than 2.6 times in the Ca and Pl treatments as compared with the Co and Eq treatments, which were similar between them. Nornicotine, anabasine and anatabine were mutually correlated and showed similar concentration patterns, being higher in the Eq treatment. Results are discussed in terms of the adaptive significance of plant responses to ecologically important VS stimuli.

Biology and ecology of Alchisme grossa in a cloud forest of the Bolivian Yungas.

Treehoppers (Membracidae) exhibit different levels of sociality, from solitary to presocial. Although they are one of the best biological systems to study the evolution of maternal care in insects, information on the biology of species in this group is scarce. This work describes the biology and ecology of Alchisme grossa (Fairmaire) (Hemiptera: Membracidae) in a rain cloud forest of Bolivia. This subsocial membracid utilizes two host-plant species, Brugmansia suaveolens (Humb. & Bonpl. ex Wild) Bercht. & J.Presl and Solanum ursinum (Rusby) (both Solanaceae), the first one being used during the whole year and the second one almost exclusively during the wet season. The development of A. grossa from egg to adult occurred on the plant where eggs were laid. Maternal care was observed during the complete nymphal development, and involved behavioral traits such as food facilitation and antidepredatory defense. Life cycle was longer on B. suaveolens during the dry season and shorter on S. ursinum during the wet season. Mortality was similar on both host plants during the wet season but was lower on B. suaveolens during the dry season. The presence of a secondary female companion to the egg-guarding female individual and occasional iteropary is also reported.

Strong selection on mandible and nest features in a carpenter bee that nests in two sympatric host plants.

Host plants are used by herbivorous insects as feeding or nesting resources. In wood-boring insects, host plants features may impose selective forces leading to phenotypic differentiation on traits related to nest construction. Carpenter bees build their nests in dead stems or dry twigs of shrubs and trees; thus, mandibles are essential for the nesting process, and the nest is required for egg laying and offspring survival. We explored the shape and intensity of natural selection on phenotypic variation on three size measures of the bees (intertegular width, wing length, and mandible area) and two nest architecture measures (tunnel length and diameter) on bees using the native species Chusquea quila (Poaceae), and the alloctonous species Rubus ulmifolius (Rosaceae), in central Chile. Our results showed significant and positive linear selection gradients for tunnel length on both hosts, indicating that bees building long nests have more offspring. Bees with broader mandibles show greater fitness on C. quila but not on R. ulmifolius. Considering that C. quila represents a selective force on mandible area, we hypothesized a high adaptive value of this trait, resulting in higher fitness values when nesting on this host, despite its wood is denser and hence more difficult to be bored.