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Las abejas sin aguijón son importantes para los ecosistemas por su papel ecológico como polinizadores. En Nicaragua se sabe poco acerca de su diversidad. En este trabajo, se realizó el primer inventario de abejas sin aguijón en el corredor biológico Paso del Istmo de Rivas, Nicaragua, en los municipios de Cárdenas, San Juan del Sur y Rivas. Se realizaron 31 muestreos dirigidos en plantas en floración en los tres municipios en diferentes agroecosistemas. La colecta se hizo con la técnica de red entomológica principalmente en plantas en floración visitadas por las abejas. Se hizo búsqueda de material bibliográfico que demuestren registros de abejas sin aguijón, actualizando de esta manera las especies reportadas en Nicaragua. En total, se colectaron 109 ejemplares correspondiendo a 11 géneros y 21 especies. Predominan los géneros Plebeia Schwarz, 1938, Scaptotrigona Moure, 1942, Partamona Schwarz, 1939 y Trigona Jurine, 1807. Además, se reportan las especies Nannotrigona perilampoides (Cresson, 1878), Partamona bilineata (Say, 1837), Plebeia moureana Ayala, 1999, Scaura argyrea (Cockerell, 1912), Trigona nigerrima Cresson, 1878, Trigona muzoensis Schwarz, 1948 como nuevos registros para el país, incrementando a 35 especies de abejas sin aguijón registradas en Nicaragua.

Los bosques, selvas y otras asociaciones vegetales han sufrido un proceso de degradación ambiental, atribuido a la deforestación y a la fragmentación con el objetivo de ampliar la frontera agrícola-pecuaria. Estos cambios ambientales no pasan desapercibidos para las comunidades faunísticas presentes, como las aves. Una manera confiable de conocer las posibles afectaciones antropogénicas en los ecosistemas es a través del análisis de los gremios tróficos aviares, ya que los cambios en la estructura de la vegetación condicionan la presencia de diferentes gremios tróficos. El objetivo principal del presente estudio fue analizar las variaciones en la riqueza, abundancia y composición de las comunidades de aves y los gremios tróficos en tres diferentes condiciones de cobertura vegetal (selva con regeneración SCR, ecotonos ECO, y un poblado POB), en una región de la Selva Lacandona, Chiapas, México. El muestreo se realizó durante cuatro meses del 2020 donde se recorrieron seis transectos de aproximadamente 2 km de longitud cada uno. Se registraron en total 6,190 individuos de 201 especies de aves. El ECO presentó la mayor riqueza de aves con 155 especies, seguido por la SCR (104 especies) y finalmente, el POB (101 especies). Sin embargo, el POB presentó la mayor abundancia de individuos (2,661 individuos) con respecto a las otras dos condiciones ambientales. La mayor semejanza de las comunidades avifaunísticas ocurrió entre el poblado y el ecotono (53 %). El mayor número de gremios tróficos también se registró en el ECO (15). En general, los insectívoros tuvieron una buena representatividad, particularmente en la SCR. Por el contrario, los granívoros estuvieron relacionados con los espacios abiertos y semiabiertos, desprovistos de vegetación arbórea (POB y ECO). Los frugívoros tuvieron mayor número de especies en el ECO, pero fueron más abundantes en el POB. Mientras que, los nectarívoros se observaron con mayor frecuencia en el POB. La deforestación y la fragmentación reducen el espacio físico de los ecosistemas y también alteran la disponibilidad de alimento para las aves. Lo anterior, se verá reflejado en la presencia-ausencia de los diferentes gremios tróficos y en las funciones ecológicas que son capaces de realizar.

We present a review of the genus Xylocopa (Neoxylocopa) of Mexico and Mesoamerica in which 11 species are recognized, including: X. clarionenis, X. fimbriata, X. frontalis, X. gualanensis, X. mexicanorum, X. nautlana, X. ocellaris, X. sonorina, X. wilmattae. Additionally, two new species are described, X. griswoldi sp. nov. with distribution in the United States and Mexico, and X. maya sp. nov. present in Mexico and Belize. Three species groups within the subgenus Neoxylocopa are recognized: frontalis, mexicanorum and sonorina. Identification keys are presented for identifying species groups and species. Furthermore, images of species and morphological structures as well as information regarding distribution are provided.

Los abejorros sociales del género Bombus son componentes muy importantes de la biodiversidad de México. Son polinizadores de una gran variedad de plantas, muchas de ellas cultivos de gran importancia comercial como los jitomates y los chiles y son componentes fundamentales de los ecosistemas donde habitan. Muchas especies están amenazadas por el crecimiento urbano, el cambio climático y el desarrollo de la agricultura a escala industrial aunque, paradójicamente, algunas especies son indispensables en la agricultura protegida. En este libro se reúne el conocimiento actual sobre las 22 especies nativas de abejorros mexicanos que se reconocen formalmente y sobre una especie introducida, precisamente asociada con la agricultura industrial. Aunque no se puede considerar como una obra definitiva sobre los abejorros mexicanos, es una primera propuesta encaminada a condensar aspectos generales de la biología y la conservación de los abejorros mexicanos, en combinación con un tratamiento taxonómico preciso y detallado, pero accesible a cualquier lector interesado, incluyendo también a los especialistas. Esta obra fue elaborada por un equipo de biólogos conocedores de los abejorros mexicanos y está ricamente ilustrada, con mapas originales de distribución de las especies y con imágenes artísticas magistralmente logradas por dos de los autores. Para todas las especies se presentan ilustraciones científicas por primera vez, lo que hace de este Atlas una obra magnífica y digna de conocer y coleccionar.

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Actualmente los ambientes heterogéneos son los que predominan en los paisajes tropicales, por lo que estudiar la diversidad y la composición de especies en las comunidades avifaunísticas ha permitido entender la variación y la estructura de las mismas. Asimismo, esta información permite implementar estrategias de manejo y conservación en estos ambientes. En este estudio se evaluó la diversidad y composición espacial y temporal de la comunidad de aves en el Parque Nacional Lagunas de Montebello, Chiapas, en diferentes tipos de bosques y condiciones (bosques de pino, pino-encino, pino-encino-liquidambar, bosque mesófilo, vegetación riparia y zonas intervenidas). El muestreo se realizó de febrero a julio de 2017 en 110 puntos de conteo separados cada 300 m. En total se registraron 3,143 aves de 123 especies. La diversidad medida con el orden q= 1 fue de 41.67 y con q= 2 fue de 24.79 especies efectivas. La temporada de lluvias presentó una mayor diversidad de especies de aves que en secas. Los gremios mejor representados fueron los granívoros-frugívoros-insectívoros, los insectívoros y los omnívoros. Las zonas con intervención, así como los bosques de pino y la vegetación riparia presentaron la mayor diversidad de especies. En contraste, el bosque mesófilo de montaña, de pino-encino-liquidambar y de pino-encino presentaron especies raras y vulnerables como Setophaga chrysoparia, Pharomachrus mocinno y Penelopina nigra. Este estudio permite identificar sitios de monitoreo y de manejo forestal para el mejor ordenamiento en el parque nacional.

Bumble bees are an ecologically and economically important group of pollinating insects worldwide. Global climate change is predicted to affect bumble bee ecology including habitat suitability and geographic distribution. Our study aims to estimate the impact of projected climate change on 18 Mesoamerican bumble bee species. We used ecological niche modeling (ENM) using current and future climate emissions scenarios (representative concentration pathway 4.5, 6.0, and 8.5) and models (CCSM4, HadGEM2-AO, and MIROC-ESM-CHEM). Regardless of the scenario and model applied, our results suggest that all bumble bee species are predicted to undergo a reduction in their potential distribution and habitat suitability due to projected climate change. ENMs based on low emission scenarios predict a distribution loss ranging from 7% to 67% depending on the species for the year 2050. Furthermore, we discovered that the reduction of bumble bee geographic range shape will be more evident at the margins of their distribution. The reduction of suitable habitat is predicted to be accompanied by a 100-500 m upslope change in altitude and 1-581 km shift away from the current geographic centroid of a species' distribution. On average, protected natural areas in Mesoamerica cover ~14% of each species' current potential distribution, and this proportion is predicted to increase to ~23% in the high emission climate change scenarios. Our models predict that climate change will reduce Mesoamerican bumble bee habitat suitability, especially for rare species, by reducing their potential distribution ranges and suitability. The small proportion of current and future potential distribution falling in protected natural areas suggests that such areas will likely have marginal contribution to bumble bee habitat conservation. Our results have the capacity to inform stakeholders in designing effective landscape management for bumble bees, which may include developing restoration plans for montane pine oak forests habitats and native flowering plants.

Climate oscillations have left a significant impact on the patterns of genetic diversity observed in numerous taxa. In this study, we examine the effect of Quaternary climate instability on population genetic variability of a bumble bee pollinator species, Bombus huntii in western North America. Pleistocene and contemporary B. huntii habitat suitability (HS) was estimated with an environmental niche model (ENM) by associating 1,035 locality records with 10 bioclimatic variables. To estimate genetic variability, we genotyped 380 individuals from 33 localities at 13 microsatellite loci. Bayesian inference was used to examine population structure with and without a priori specification of geographic locality. We compared isolation by distance (IBD) and isolation by resistance (IBR) models to examine population differentiation within and among the Bayesian inferred genetic clusters. Furthermore, we tested for the effect of environmental niche stability (ENS) on population genetic diversity with linear regression. As predicted, high‐latitude B. huntii habitats exhibit low ENS when compared to low‐latitude habitats. Two major genetic clusters of B. huntii inhabit western North America: (a) a north genetic cluster predominantly distributed north of 28°N and (b) a south genetic cluster distributed south of 28°N. In the south genetic cluser, both IBD and IBR models are significant. However, in the north genetic cluster, IBD is significant but not IBR. Furthermore, the IBR models suggest that low‐latitude montane populations are surrounded by habitat with low HS, possibly limiting dispersal, and ultimately gene flow between populations. Finally, we detected high genetic diversity across populations in regions that have been climatically unstable since the last glacial maximum (LGM), and low genetic diversity across populations in regions that have been climatically stable since the LGM. Understanding how species have responded to climate change has the potential to inform management and conservation decisions of both ecological and economic concerns.

Summary Traditional tropical agriculture often entails a form of slash‐and‐burn land management that may adversely affect ecosystem services such as pollination, which are required for successful crop yields. The Yucatán Peninsula of Mexico has a >4000 year history of traditional slash‐and‐burn agriculture, termed ‘milpa’. Hot ‘Habanero’ chilli is a major pollinator‐dependent crop that nowadays is often grown in monoculture within the milpa system.We studied 37 local farmers’ chilli fields (sites) to evaluate the effects of landscape composition on bee communities. At 11 of these sites, we undertook experimental pollination treatments to quantify the pollination of chilli. We further explored the relationships between landscape composition, bee communities and pollination service provision to chilli.Bee species richness, particularly species of the family Apidae, was positively related to the amount of forest cover. Species diversity decreased with increasing proportion of crop land surrounding each sampling site. Sweat bees of the genus Lasioglossum were the most abundant bee taxon in chilli fields and, in contrast to other bee species, increased in abundance with the proportion of fallow land, gardens and pastures which are an integral part of the milpa system.There was an average pollination shortfall of 21% for chilli across all sites; yet the shortfall was unrelated to the proportion of land covered by crops. Rather, chilli pollination was positively related to the abundance of Lasioglossum bees, probably an important pollinator of chilli, as well indirectly to the proportion of fallow land, gardens and pastures that promote Lasioglossum abundance. Synthesis and applications. Current, low‐intensity traditional slash‐and‐burn (milpa) agriculture provides Lasioglossum spp. pollinators for successful chilli production; fallow land, gardens and pasture therefore need to be valued as important habitats for these and related ground‐nesting bee species. However, the negative impact of agriculture on total bee species diversity highlights how agricultural intensification is likely to reduce pollination services to crops, including chilli. Indeed, natural forest cover is vital in tropical Yucatán to maintain a rich assemblage of bee species and the provision of pollination services for diverse crops and wild flowers., Current, low‐intensity traditional slash‐and‐burn (milpa) agriculture provides Lasioglossum spp. pollinators for successful chilli production; fallow land, gardens and pasture therefore need to be valued as important habitats for these and related ground‐nesting bee species. However, the negative impact of agriculture on total bee species diversity highlights how agricultural intensification is likely to reduce pollination services to crops, including chilli. Indeed, natural forest cover is vital in tropical Yucatán to maintain a rich assemblage of bee species and the provision of pollination services for diverse crops and wild flowers.

International audience; The conservation of pollinator diversity is fundamental to maintaining sustainable agricultural systems and food security. Some agricultural systems support pollinator diversity, while others may lead to their decline. Previous studies have evaluated the impacts of agricultural intensification on pollinators in temperate climates regions, but in tropical regions these impacts have been evaluated by only very few studies. We conducted a study in southeastern Mexico, in order to understand the effects of three agricultural systems on bee diversity in a tropical landscape. We compared 18 sites at two different scales (plot scale and landscape scale). We found a link between agricultural system intensity level at the plot scale and forest proportion at the landscape scale: land use intensity was low at both scales in 7 polycultures, low at plot scale and high at landscape scale in 4 pastures, and high at both scales in 7 monocultures. We collected bees at all sites, and found an overall high bee richness, with a total of 127 species. Bee richness was compared across agricultural systems using diversity accumulation curves with iNEXT package. Both polycultures and pastures had significantly higher richness as monocultures. We constructed bee species guilds according to ecological and life-history traits (i.e. size, sociality and nesting) and found that whatever the trait considered, the species richness in the different agricultural systems was most often affected in the same way than the complete community richness. Our results show, for the first time in tropical conditions that agricultural systems with low-intensity farming practices and forested landscape allow the preservation of a significantly higher diversity of bees than agricultural systems with high-intensity farming practices and highly deforested landscape. Considering that bee diversity is key to maintaining crop productivity, these findings can help scientists, policy-makers, and community members design policies that support both agricultural production and biodiversity conservation in the tropics.

Mexico and Central America are among the most biodiverse regions on Earth, harboring many species with high levels of interpopulation morphological and genetic diversity. The mountainous topography of this region contains isolated sky island habitats that have the potential to promote speciation. This has been studied in vertebrates, yet few studies have examined the phylogeographic and genetic structure of insect species encompassing this region. Here we investigate geographic patterns of genetic and morphological divergence and speciation among widespread populations of the highly polymorphic bumble bee Bombus ephippiatus and its closest relative B. wilmattae. We used DNA sequences from a fragment of cytochrome oxidase I (COI), genotypes for twelve microsatellite markers, and morphometric data from wings to construct a well-supported inference of the divergences among these taxa. We have found complex patterns of genetic isolation and morphological divergence within B. ephippiatus across its geographic range and present evidence that B. ephippiatus comprises multiple independent evolutionary lineages. The pattern of their diversification corresponds to geographic and environmental isolating mechanisms, including the Mexican highlands, the lowlands of the Isthmus of Tehuantepec in southern Mexico, the Nicaraguan Depression, the patchily distributed volcanic ranges in Nuclear Central America and Pleistocene glacial cycles. These results have important implications for the development and distribution of B. ephippiatus as a commercial pollinator in Mexico and Central America.

When coffee is grown under shade trees, as in Mexico and Guatemala, coffee landscapes are complex and offer a high diversity of plants to the bees. This study focuses on the manner in which bees adapt their foraging behavior as a function of variation in tree coverage on a landscape scale. Study sites were characterized by satellite images and categorized according to percentage of tree cover: low (50–62%), medium (63–77%), and high (77–83%). Honey samples were collected from several apiaries in each landscape. In order to identify resources used by Apis mellifera, samples were analyzed according to melissopalynology. A random forest model analysis performed to compare different honeys did not show significant differences between honeys in any given landscape. Nevertheless, percentage of tree cover was positively correlated, in a significant manner, with the relative proportion of pollen from trees and from shrubs present in honey samples. These analyses, along with physical–chemical and sensory analyses ...

"Se aportan nuevos registros a la fauna de abejas sin aguijón (tribu Meliponini) para los estados de Oaxaca y Chiapas. Para ello, se hicieron muestreos intensivos de estas abejas, con lo cual se reunieron registros de distribución, incluyendo las aportadas por investigadores, las presentes en colecciones y los reportados en la literatura. Se tienen 12 registros nuevos de especies de abejas sin aguijón para Oaxaca y se confirma la presencia en Chiapas de Paratrigona opaca. Adicionalmente, se discute sobre la distribución de estas abejas en estos estados y el país. Se espera que la información sobre la fauna y la distribución de las abejas sin aguijón ayude en los esfuerzos de conservación regional, uso de estas abejas en la meliponicultura y la polinización."

Despite their relevant contribution to the conservation of tropical ecosystems and crop productivity through pollination, the stingless bees (Apidae: Meliponini) can be considered a group of neglected species in the assessment of pesticides upon nontarget organisms. In this article, we evaluated the effect of aerial sprays of the spinosad-based fruit fly toxic bait GF-120 upon colonies of the stingless bee Scaptotrigona mexicana Guerin (Hymenoptera: Apidae), an economically important and abundant species in some landscapes of Mexico, located in mango orchards. Colonies of the honey bee Apis mellifera L. (Hymenoptera: Apidae) were used for comparison. Eight colonies (four of A. mellifera and four of S. mexicana) were moved into each of two mango orchards, one was used as a control, with no insecticide application, and other received five weekly aerial sprays of GF-120. Foraging activity and strength of colonies of both species were measured nine times over the fruiting season, previous, during and after insecticide application. We did not find a significant difference in foraging activity and strength between exposed and control colonies of A. mellifera during the observation period. However, colonies of S. mexicana seemed to be affected by the exposure, as revealed by a reduction in colony strength. However, 1 yr later, with no insecticide applications, the colonies of both species were evaluated and found to be in good conditions. Our results showed that weekly aerial sprays of GF-120 are unlikely to generate acute poisoning in both species, even if in acute toxicity tests this product has been found to be highly active.

In this paper, we show the results of investigating the presence of organochlorine pesticides in honey and pollen samples from managed colonies of the honey bee, Apis mellifera L. and of the stingless bee Scaptotrigona mexicana Guerin. Three colonies of each species were moved into each of two sites. Three samples of pollen and three samples of honey were collected from each colony: the first collection occurred at the beginning of the study and the following ones at every six months during a year. Thus the total number of samples collected was 36 for honey (18 for A. mellifera and 18 for S. mexicana) and 36 for pollen (18 for A. mellifera and 18 for S. mexicana). We found that 88.44% and 93.33% of honey samples, and 22.22% and 100% of pollen samples of S. mexicana and A. mellifera, respectively, resulted positive to at least one organochlorine. The most abundant pesticides were Heptaclor (44% of the samples), γ-HCH (36%), DDT (19%), Endrin (18%) and DDE (11%). Despite the short foraging range of S. mexicana, the number of pesticides quantified in the honey samples was similar to that of A. mellifera. Paradoxically we found a small number of organochlorines in pollen samples of S. mexicana in comparison to A. mellifera, perhaps indicating a low abundance of pollen sources within the foraging range of this species.

In this study, drone congregations of the stingless bee Scaptotrigona mexicana Guerin were genetically analyzed at 5 microsatellite loci to estimate the number of colonies of this species in the La Sepultura Biosphere Reserve, in Chiapas, Mexico. A total of 216 drones from 3 congregations were analyzed. We found that the 3 congregations had enough genetic differences to be considered as coming from different populations. The average number (± SD) of colonies per congregation was 19.8 ± 0.63, 17.6 ± 0.70 and 12. A similar result was reported for areas where stingless beekeeping occurs. We discuss the implications of our findings in a conservation framework in which stingless beekeeping might play a significant role.

In this paper, we present a framework and a methodology to identify the long-term strategies of small-scale farmers dealing with uncertainties. To do so, we link the Activity System framework to the concept of perceived vulnerability and analyse the small-scale farmers' trajectories. Based on a sample of 34 small-scale coffee producers in Guatemala and through the analysis of case studies and classification methods, we identify some trends in long-term decisionmaking. These trends are mainly built on responsiveness, autonomy, vulnerability shifts and collective means of action. We finally discuss these findings in the light of previous studies carried out in different contexts.

Stingless bees (Apidae, Meliponini) are key pollinators in natural and agricultural Pantropical environments. Current human activities, however, threaten their populations, making it urgent to assesstheir abundance and genetic status. By a population genetics approach, we calculated the genetic diversity and estimated the number of wild colonies of two stingless bee species, Trigona nigerrima (Cresson) and T. corvina (Cockerell) in southern Mexico. Allele richness ranged from 10 to 19 (mean ± SD = 14 ± 3.5) for both species. Expected heterozygosity ranged 0.88-0.93 for T. corvina and 0.82-0.92 for T. nigerrima. The estimated number of colonies estimated was 25 on average for T. corvina and 21 for T. nigerrima. According to our results populations of both species seem not to be in danger. We also show that genetic tools can be extremely useful for colony density estimation for stingless bees as it is for bumble bees and honey bees.

Agroecosystem management commonly involves the use of pesticides. As a result, a heterogeneous landscape is created, in which suitable and unsuitable spaces are defined by the absence/presence of pesticides. In this study, we explored how foragers of the honey bee, Apis mellifera L., adapt to such context. We specifically evaluated the effect of GF-120, a spinosad-based fruit fly toxic bait, on the allocation of foragers between food sources under the hypothesis that foragers will move from food sources with GF-120 to food sources without it. We thus carried out three experiments: in experiment 1, a group of foragers was trained to collect honey solution from a feeder; next, this feeder offered a GF-120/honey solution. A minority of foragers continued collecting the GF-120/honey solution. In experiment 2, we trained two groups of foragers from a colony to two food sources equally rewarding. Next, GF-120 was added to one of the food sources. We found that the majority of foragers moved from the GF-120-treated feeder to the feeder without GF-120 and that the minority that continued visiting the GF-120-treated feeder did not collect the GF-120/honey solution. In a third experiment, we wanted to know if foragers in an experimental setup as in experiment 1 would perform waggle dances: none of the foragers that collected GF-120/honey were observed dancing. Our results emphasize the importance of "food refuges" for non-target species, since they minimize the impact of agrochemicals upon them.

Climate oscillations have left a significant impact on the patterns of genetic diversity observed in numerous taxa. In this study, we examine the effect of Quaternary climate instability on population genetic variability of a bumble bee pollinator species

Small-scale coffee producers are particularly exposed to a very fluctuant market. The present work aims at characterising the adaptation of small-scale coffee and honey producers to the 1999–2003 coffee crisis in the Guatemalan Highlands from a systemic and agronomical perspective. Working with a homogeneous sample of 34 families we identify up to 27 different flexibility mechanisms. A qualitative analysis of families' life histories was combined with classification methods. Besides confirming the importance of the availability resources and some well known adaptive responses, such as workload intensification, expenses reduction or the importance of social networks, the classification of households reveals a sequence in the implementation of flexibility mechanisms. The focus on the combination of coffee and honey productions also suggests changing the traditional approaches to agricultural processes toward the adoption of a more systemic perspective. The possible impacts of these findings on technical extension and construction of public policies are then discussed.

Studies characterizing typical honeys are carried out with the goal of establishing standards for marketing. In the case of tropical honeys, few studies exist which allow for establishing a typolog...

In this study we evaluated the effects of the biorational pesticide, Spinosad (GF-120 formulation), on foraging behavior in the stingless bee Plebeia moureana (Ayala). Several foragers were individually trained to collect an unscented 1.0 M sucrose solution (31% sucrose wt:wt) from a blue plate in one arm of a Y-tube maze. The other arm offered plain water on a yellow plate. After 20–30 visits to the setup, the sucrose solution was exchanged for a sucrose solution mixed with one of five concentrations of GF-120 and 30 consecutive choices of each bee were recorded. Interestingly, the foragers collected the sucrose solution with GF-120 at all concentrations. Our results show that: 1) the GF-120 formulation, when applied at the recommended concentration and mixed with food, does not discourage engaged foragers and, 2) foraging behavior over time is not significantly impaired by the continuous collection of GF-120.

To increase our understanding in bee vision ecology, we investigated the color and shape discrimination performance of the stingless bee Scaptotrigona mexicana Guérin. Our main goal was to describe the choice behavior of experienced foragers over time, trying to understand to what extent color and shape stimuli (separately tested) aid them to choose the rewarding option, in the presence of distracting, unrewarding stimuli. Single foragers were trained to collect sucrose solution from a target plate. Afterwards, one distracting, unrewarding plate was placed besides the target plate and eight choices were recorded. Our results showed that both color and shape stimuli assisted efficiently the trained foragers in locating the target plate. However, foragers chose significantly more often the target plate in the color experiments than in the shape experiments. In conclusion, in our experimental setup, color was of better assistance to the foragers of S. mexicana than shape to choose their rewards. This is the first study in which it is demonstrated that the choice performance over time in a stingless bee depends upon the characteristics of the resource, such as shape and color.

Tetragonisca angustula mating occurs during the virgin queen nuptial flight, usually in the presence of a drone congregation area (DCA). The presence of virgin queen pheromone is considered the trigger for DCA establishment, although this has not been demonstrated experimentally. We established meliponaries, in different habitats, with T. angustula virgin queens during the main drone reproduction period. Eight DCAs were observed in urban areas, and all established outside or near colonies containing at least one virgin queen. The accumulation of drones in the DCAs occurred from 08:00 to 18:00 h and over 3-35 days. The number of drones in DCAs ranged from 60 to 2,000. In field trials, drones were attracted to virgin queens and also, unexpectedly, to physogastric queens. Volatiles collected from both virgin and physogastric queens elicited strong electoantennogram (EAG) responses from drones. Virgin and physogastric queen volatiles were qualitatively similar, but quantitatively different, in chemical composition. The queen's abdomen was the principal source of these compounds. Isopropyl hexanoate (IPH), the most abundant compound in virgin queen volatiles and one of the most abundant in physogastric queen volatiles, was identified as one of the compounds that elicited EAG responses and was demonstrated to attract drones in a field test.

Multimodal communication plays an important role in pollination biology. Bees have evolved multimodal communication to recruit nestmates to rewarding food sources. Highly social bees can use visual and chemical information to recruit nestmates to rich food sources. However, no studies have determined if this information is redundant or has an additive effect such that multimodal information is more attractive than either modality presented by itself to free-flying bees. We tested the effect of two modalities, forager-deposited odor marks and the visual presence of foragers, on the orientation of stingless bee (Scaptotrigona mexicana) recruits. Our results show that odor marks alone were significantly more attractive than multimodal information, and that multimodal information was significantly more attractive than visual forager presence alone. Given the high olfactory sensitivity and limited visual acuity of insects, odor marks likely attracted recruits over a greater distance than the visual presence of nestmates. Thus, multimodal information in S. mexicana is redundant, not additive, in terms of orientation to food sources.

We present the results of evaluating the response of three species of bees, Trigona fulviventris (Guérin), Scaptotrigona mexicana (Guérin-Meneville), and Apis mellifera (L.), to food sources baited with the toxic bait GF-120 (NF Naturalyte), a spinosad-based bait exclusively used to manage fruit flies. Groups of foragers were trained to collect honey and water from a feeder located 50 m from the colonies. Once a sufficient number of foragers were observed at the experimental location, the training feeder was changed to two or three feeders that offered either honey and water, GF-120, Captor (hydrolyzed protein), GF-120 and honey (4:6), or Captor and honey (1:19). T fulviventris and S. mexicana rarely visited GF-120, Captor, or their mixtures with honey, while approximately 28.5 and 1.5% of A. mellifera foragers visited the GF-120 and honey and Captor and honey mixtures, respectively. Our results show that GF-120 clearly repels T. fulviventris and S. mexicana, whereas for A. mellifera, repellence is not as marked when GF-120 is combined with highly nutritious substances like honey.

In this paper, we show the results of investigating the presence of organochlorine pesticides in honey and pollen samples from managed colonies of the honey bee, Apis mellifera L. and of the stingless bee Scaptotrigona mexicana Guérin. Three colonies of each species were moved into each of two sites. Three samples of pollen and three samples of honey were collected from each colony: the first collection occurred at the beginning of the study and the following ones at every six months during a year. Thus the total number of samples collected was 36 for honey (18 for A. mellifera and 18 for S. mexicana) and 36 for pollen (18 for A. mellifera and 18 for S. mexicana). We found that 88.44% and 93.33% of honey samples, and 22.22% and 100% of pollen samples of S. mexicana and A. mellifera, respectively, resulted positive to at least one organochlorine. The most abundant pesticides were Heptaclor (44% of the samples), γ-HCH (36%), DDT (19%), Endrin (18%) and DDE (11%). Despite the short foraging range of S. mexicana, the number of pesticides quantified in the honey samples was similar to that of A. mellifera. Paradoxically we found a small number of organochlorines in pollen samples of S. mexicana in comparison to A. mellifera, perhaps indicating a low abundance of pollen sources within the foraging range of this species.

The Latin American subcontinent contains some of the world’s major honey producing and exporting countries, but the status of bee health in this part of the world has not been clearly documented. There have been no reports of massive colony losses in Latin America, at least from the symptoms of CCD (colony collapse disorder) or in the proportion and extent of the situations in the US and Europe. We examine possible reasons for the difference, and develop hypotheses that this prevailing good bee health could be due to: (1) the management of generally unselected bees with a certain natural resistance to diseases (tropical regions) or the selection of disease resistant bees (temperate regions); (2) a lower proportion of cropland over the total land area, resulting in more abundant or higher-quality pollen resources for bees; (3) the generally small-scale, low-income and little subsidized agriculture, and concomitant lower use of insecticides compared to industrialized countries. These general parameters may act synergistically, resulting in a large number of configurations across the tremendous ecological, social and economic diversity of Latin America. We suggest that the health of honey bees in Latin America may be ultimately due to the practices of low-income agriculture and beekeeping in the region, leading to more sustainable conditions for the bees. However the increasing trend of land use intensification in some parts of Latin America could lead to declines in honey bee health and population size.

Within a rewarding floral patch, eusocial bee foragers frequently switch sites, going from one flower to another. However, site switching between patches tends to occur with low frequency while a given patch is still rewarding, thus reducing pollen dispersal and gene flow between patches. In principle, forager switching and gene flow between patches could be higher when close patches offer similar rewards. We investigated site switching during food recruitment in the stingless bee Scaptotrigona mexicana. Thus, we trained three groups of foragers to three feeders in different locations, one group per location. These groups did not interact each other during the training phase. Next, interaction among trained foragers was allowed. We found that roughly half of the foragers switched sites, the other half remaining faithful to its training feeder. Switching is influenced by the presence of recruitment information. In the absence of recruitment information (bees visiting and recruiting for feeders), employed foragers were site specific. Foragers only switched among feeders that were being visited and recruited to. Switching was not caused by learned aversion to experimental handling. Switching in response to recruitment could provide a fitness benefit to the colony by facilitating rapid switching among exploited patches and provide a benefit of increasing plant gene flow between patches.

Eusocial bee (Apidae) foragers are able to mark food sources with olfactory attractant or repellent signals. Because these bees also have an excellent ability to learn associatively, they may be able to associate forager-deposited marks either positively or negatively with food depending on reward quality. We provide the first field experiments showing such a context-based interpretation of field information (odour marks and visual local enhancement) in stingless bees. We sequentially exposed individual foragers of the stingless bee Scaptotrigona mexicana to three situations in which one feeder was marked with either the visual presence of nestmates (sealed inside clear containers to prevent odour release) or odour marks alone. In the first situation, we offered two equally rewarding sucrose feeders (unscented 2.5 M sucrose solution). In this case, experienced foragers showed no preference on their subsequent visits to any of the feeders, even though the marked feeder was made more conspicuous with odour marks or the visual presence of nestmates. In the second situation, experienced foragers significantly preferred the marked feeder when it offered a sucrose reward. In the third situation, when the marked feeder offered no carbohydrate reward (only water) and the unmarked feeder offered sucrose, the experienced foragers avoided the marked feeder and significantly preferred the unmarked one. Thus, foragers learned to associate food quality positively or negatively with chemical or visual marks at the food source.

As a general rule, within an ecological guild, there is one species that is dominant and is commonly the most abundant. The aim of this work was to investigate if such pattern occurs intraspecifically, among colonies of the stingless bee Scaptotrigona mexicana Guerin. Through behavioral and molecular techniques, we found preliminary evidence that apparently colonies of this species do not monopolize resources, instead they seem to share food; however, some colonies had more foragers in a food patch or in a feeder, so some type of exclusion could be at work, though we could not determine the final output of such interaction, i.e., if underrepresented colonies were eventually excluded, developed slower or were overrepresented in other food patches. Our results give evidence that resource partitioning within this species occurs peacefully; however, further studies are necessary to determine if threatening behavior or aggressions appear when resources are scarce and competition becomes harsher.

Bumblebees are highly valued for their pollination services in natural ecosystems as well as for agricultural crops. These precious pollinators are known to be declining worldwide, and one major factor contributing to this decline are infections by parasites. Knowledge about parasites in wild bumblebee populations is thus of paramount importance for conservation purposes. We here report the geographical distribution of Crithidia and Nosema, two common parasites of bumblebees, in a yet poorly investigated country: Mexico. Based on sequence divergence of the Cytochrome b and Glycosomal glyceraldehyde phosphate deshydrogenase (gGPDAH) genes, we discovered the presence of a new Crithidia species, which is mainly distributed in the southern half of the country. It is placed by Bayesian inference as a sister species to C. bombi. We suggest the name Crithidia mexicana for this newly discovered organism. A population of C. expoeki was encountered concentrated on the flanks of the dormant volcanic mountain, Iztaccihuatl, and microsatellite data showed evidence of a bottleneck in this population. This study is the first to provide a large-scale insight into the health status of endemic bumblebees in Mexico, based on a large sample size (n=3,285 bees examined) over a variety of host species and habitats.

Une etude sur un an a ete realisee en 2003 sur des colonies d'abeilles africanisees (Apis mellifera) et des colonies hybrides africanisees x europeennes. Le but etait d'elucider les facteurs de la reproduction de l'acarien Varroa destructor lies a la variation du nombre de descendantes fecondees produites par fondatrice sur couvain d'ouvrieres (Wr) et le role joue par la densite des acariens sur leur reproduction. Les 18 colonies utilisees ont ete infestees naturellement. Des echantillons de couvain d'ouvrieres et de mâles ont ete preleves dans chaque colonie toutes les cinq semaines. Les acariens ont ete elimines de chaque cellule infestee et l'âge des nymphes a ete determine. Le taux de mortalite des descendants a ete determine dans 601 cellules de couvain d'ouvrieres et 142 cellules de couvain de mâles. Dans les deux types de cellules il y a eu plus de morts dans les descendants du troisieme oeuf produit que dans ceux du premier (Fig. 3). Pour le couvain d'ouvrieres, la mortalite des acariens au cours de l'annee a semble augmenter de mars a juin (Fig. 4). Une analyse de regression simple a montre que la mortalite du premier descendant (mâle) et du troisieme (femelle) rendait compte respectivement de 67 % et 53 % de la variation de Wr. (Fig. 5). On a observe une forte reduction du nombre moyen d'oeufs produits et des facteurs Wr et Dr dans les cellules mono-infestees par rapport aux cellules pluriinfestees (Tab. I). Les resultats obtenus montrent l'existence de deux mecanismes qui peuvent expliquer les fluctuations cycliques de Wret donc la resistance des abeilles africanisees a V. destructor : la mort du premier et du troisieme descendant ainsi que la reduction des capacites reproductives due a l'accroissement de la densite des fondatrices.

Nous avons mene une etude afin d'evaluer la croissance de la population de Varroa destructor dans des colonies d'abeilles africanisees et dans deux types de colonies mixtes (europeenne hygienique x africanisee et europeenne commerciale x africanisee) au Mexique. La contribution relative des trois mecanismes qui conferent aux abeilles la resistance a l'acarien a ete estimee toutes les cinq semaines durant une annee. Sur les 46 colonies d'origine, 18 colonies, dont six de chaque type, ont survecu jusqu'a la fin de l'etude avec leur reine d'origine. Les mesures des mecanismes de resistance ont ete evalues par les protocoles suivants : (i) comportement hygienique (pourcentage de couvain tue par le froid elimine), (ii) comportement de toilettage (proportion d'acariens mutiles sur un plateau de fond enduit de matiere grasse), (iii) capacite de reproduction du parasite par la fertilite (proportion d'acariens qui se reproduisent), (iv) fecondite (nombre total de descendants par fondatrice) et (v) nombre de descendants femelles fecondees produites par fondatrice (Wr). Les populations d'abeilles et d'acariens des 18 colonies ont varie de facon significative en fonction du temps et des trois types d'abeilles (Figs. 1 et 2). Des changements significatifs au cours de l'annee ont ete observes pour Wr, la fertilite et la mutilation des acariens (Figs. 3 et 4). Ces changements correspondaient aux variations du nombre estime d'acariens par colonie. Des differences significatives en fonction de la periode de l'annee et du type d'abeilles ont ete trouvees pour le comportement hygienique (Fig. 3), bien qu'aucune des colonies n'ait pu etre consideree comme fortement hygienique, puisque l'elimination du couvain mort a toujours ete inferieure a 95 %. Le comportement hygienique ne correspondait aux fluctuations des populations d'abeilles ou d'acariens. Nous emettons l'hypothese que si les mecanismes de resistance ont un effet sur la croissance de la population d'acariens, l'effet se fera sentir dans la periode d'echantillonnage suivante (cinq semaines plus tard) et pas immediatement. L'analyse factorielle a montre que les deux mecanismes rendaient compte de la variation d'acariens par colonie au cours du temps : Wr (r 2 = 0,732 ; P = 0,003 ; n = 9 ; Fig. 5a) et de la proportion d'acariens mutiles (r2 = 0,506 ; P = 0,032 ; n = 9 ; Fig. 5c). Quand on inclut ces deux mecanismes, on trouve un modele multi-factoriel significatif (r2 = 0,973 ; P = 0,0001 ; n = 9). Aucune difference n'a ete observee entre les abeilles africanisees et les colonies d'abeilles croisees dans le degre d'expression des mecanismes de resistance.

The case of a host-parasite relationship may provide a good model to evaluate the costs and bene- fits of some behaviors, an area in which field data a currently lacking. European (EHB) and Africanized (AHB) honey bees are two Apis mellifera subspecies that coexist in Mexico, the former highly compatible with Varroa destructor, the latter less compatible. Here we examine two mechanisms that could explain the low compatibility between AHB and V. destructor in Mexico: (1) grooming behavior appeared significantly more intensive in AHB colonies, but was nevertheless ineffective; (2) EHB removed 8.03% of the infested brood, while AHB removed 32.46%, especially between 5 and 7 days post-capping. Though the cost of re- moving infested brood was not different between subspecies, the result, in terms of the amount of removed in- fested brood, was significantly higher for AHB. For both bees, there is thus a real cost, since removing a pupa results in a lower number of adult bees. We discuss the possibility that the removal of infested brood corre- sponds with a threshold above which the cost of removal becomes greater than the benefit. Apis mellifera / Varroa destructor / parasitology / costs and benefits / behavioral resistance

We investigated the relationships between the honey bee, Apis mellifera, and the parasitic mite Varroajacobsoni in Mexico. In an 18-month survey of European honey bees (EHB) and Africanized honey bees (AHB), weshowed that EHB were highly compatible with V. jacobsoni, while AHB were not as compatible. Furthermore, miteinfertility (“parasite infectivity” factor), suspected to be the main factor of low AHB/ V. jacobsoni compatibility inBrazil, was not observed in Mexico. The “intrinsic rate of natural increase” of mites did not differ significantly be-tween host subspecies, indicating that the cause of low compatibility appears only at high parasite densities. The “car-rying capacity” was twice as high in EHB as in AHB, indicating that the cause of low compatibility is possibly linkedto honey bees’ behavior. We hypothesize that the reason why V. jacobsoni is highly fertile on Mexican AHB (whereasit has low fertility on Brazilian AHB) may be that different strains of V. jacobsoni exist in the two countries.Resume : Nous avons etudie la relation entre l’Abeille domestique, Apis mellifera, et l’acarien parasite Varroa jacob-soni au Mexique. Au cours d’un inventaire d’une duree de 18 mois des abeilles europeennes (EHB) et des abeilles afri-canisees (AHB), nous avons demontre que les premieres etaient tres compatibles avec l’acarien, et que les secondesl’etaient beaucoup moins. De plus, la sterilite des acariens (facteur d’infectivite chez le parasite), que l’on croit etre lefacteur principal de la faible compatibilite de AHB/V. jacobsoni au Bresil, n’a pas ete observee au Mexique. Le« potentiel biotique » des acariens ne differait pas significativement entre les sous-especes d’hotes, ce qui semble indi-quer que la faible compatibilite n’apparait que lorsque la densite des parasites est elevee. Le stock limite etait deuxfois plus eleve chez les abeilles EHB que chez les abeilles AHB et donc la faible compatibilite est sans doute reliee aucomportement des abeilles. Nous croyons que V. jacobsoni est probablement tres fertile sur les abeilles AHB mexicai-nes (et tres peu fertile sur celles du Bresil), peut-etre a cause de l’existence de souches differentes deV. jacobsoni dansles deux pays.[Traduit par la Redaction] Vandame et al. 2044

The effects of sublethal doses of deltamethrin, a pyrethroid insecticide, and prochloraz and difenoconazole, two azole fungicides, on honey bee thermoregulation were investigated by infrared thermography of honey bees kept at 22 degrees C. Deltamethrin at doses of 0.5 and 1.5 ng/bee did not elicit any significant effect on bee thermogenesis whereas doses of 2.5 and 4.5 ng/bee caused a severe hypothermia. Similarly, prochloraz and difenoconazole did not elicit any significant effect on thermogenesis at doses of up to 850 ng/bee whereas they triggered hypothermia at 1250 ng/bee. When associated with prochloraz or difenoconazole at 850 ng/bee, deltamethrin elicited a joint hypothermia at doses that did not induce a significant effect on thermoregulation when used alone.

La relation dose de fluvalinate-mortalite de l'acarien a ete construite a partir de parasites preleves sur trois types de ruchers : i) ruchers ou l'apiculteur n'observe pas de parasites apres traitement; ii) ruchers ou l'apiculteur ne remarque que quelques parasites apres traitement ou ruchers places a proximite de ruchers dans lesquels le traitement au fluvalinate a ete inefficace ; iii) ruchers ou la varroose demeure grave malgre la repetition des traitements avec cet acaricide. Sept dilutions de la formulation commerciale Klartan (240g/L de fluvalinate), espacees selon une progression geometrique de raison deux (figs 1, 2 et 3 en abscisse), ont ete pulverisees sur le fond de boites de Petri pour obtenir un depot de 1,5 a 2 mg par cm 2 . Soixante parasites, extraits du couvain, ont ete mis en contact avec chaque dilution, pour une colonie. La mortalite a ensuite ete relevee apres 24 et 48 h d'incubation a 33 °C et 50 % d'humidite relative. Le type de la regression dose-letalite a ete choisi en fonction du meilleur ajustement aux donnees experimentales puisque la population parasitaire d'une colonie est vraisemblablement composee des deux phenotypes resistant et sensible. Dans un cas (figs 3 et 4), nous avons applique la regression segmentaire d'Otto. Les CL50 a 24 h varient entre 0,73 et 131,54 ng de fluvalinate par cm 2 et les CL90 a 24 h entre 2,83 et 259,52 ng/cm 2 (tableau I). Lorsqu'on utilise la regression segmentaire d'Otto, la CL50 des parasites les plus sensibles est de 2 ng/cm 2 et de 128 ng/cm 2 pour les resistants (fig 4). L'hypothese de l'existence des deux phenotypes (resistant et sensible) dans la population parasitaire d'une colonie est donc confortee. Le coefficient de resistance le plus eleve est de 182,7 (tableau I), ce qui rend inutile toute augmentation de dose therapeutique lors d'une baisse d'efficacite du traitement. L'emergence de la resistance serait soupconnee si des parasites provenant d'une meme colonie et soumis 24 h a la concentration de 10 ng/cm 2 , demeuraient vivants.

International audience; The number of colonies in feral and managed honeybee populations (Apis mellifera) was determined for various sampling locations in Chiapas and Yucatan (Mexico) to assess the impact of apiculture on feral honeybee populations. We used a comparative sampling approach determining the number of colonies in similar habitats and landscapes but with different intensity of beekeeping. Sampling sites included nature reserves, and mango and shaded coffee plantations. The agricultural sites were all set in high-diversity landscapes with plenty of surrounding secondary forest. The number of colonies was determined by genotyping drones caught on drone congregation areas and assigning the drone genotypes to mother queens each heading a colony. We used three sets of linked markers each to achieve sufficient resolution for a precise colony assignment. The estimated colony numbers ranged from 34 to 54 colonies, with an average of 38.3 ± 6.9 colonies in areas with high and 43.5 ± 6.6 colonies in areas with low beekeeping activity. There was no significant difference in colony numbers between the sites with high and low beekeeping activity suggesting that the managed honeybee populations do not substantially add to the overall number of honeybee colonies supported in the wild. This might indicate that restrictions on apicultural activities to prevent any potential conservation conflict with native pollinators might not be useful, since honeybee colonies are very abundant in many different landscapes in Southern Mexico independent of apiculture.

Colonies of meliponine bees consist of hundreds to thousands of individuals, both adults and brood; however, the responsibility of bringing food home depends on just a small group of workers, the foragers. Honey, pollen, and other products that beekeepers obtain come from the hard work of these few bees. Thus in many of these species complex behavioral mechanisms have evolved in order to make more efficient the collection of food and to allow the survival of the colony. This chapter describes in some detail the processes associated with the communication systems in meliponines that permit them to improve food gathering at a social level. Given the great amount of knowledge obtained in studying honeybee communication, several references to Apis mellifera are given throughout.

We recorded stingless bee colony abundance and nesting habits in three sites with different anthropogenic activities in the Soconusco region of Chiapas, Mexico: (1) agroforestry (7 hacacao crop), (2) grassland (12 ha), and (3) urban area (3 ha). A total of 67 nests were found, representing five stingless bee species, Tetragonisca angustula angustula (Lepeletier), Trigona fulviventris (Guerin), Scaptotrigona mexicana (Guerin), Scaptotrigona pectoralis (Dalla Torre), and Oxytrigona mediorufa (Cockerell). The most abundant stingless bee in each site was T. angustula angustula (>50%). The primary tree species used by the bees were Ficus spp. (Moraceae, 37.8%) and Cordia alliodora (Boraginaceae, 13.5%). The nest entrance height of T. angustula angustula (96 ± 19 cm) was different than the other species, and this bee was the only one that used all different nesting sites. Volatiles analyzed by gas chromatography from pollen collected by the stingless bees differed between bee species, but were highly similar in respect to the fragrances of the pollen collected by the same species at any site. Our data indicate that T. angustula angustula experienced low heterospecific and high intraspecific foraging overlap especially in the urban site. We observed cluster spatial distribution in grassland and in agroforestry sites. In the urban site, T. angustula angustula presented random distribution tended to disperse. Trigona fulviventris was the only overdispersed and solitary species.

International audience; So far, nearly all studies concerning the mating frequency of bumblebees have been conducted with temperate species, showing that single mating seems to be the predominant pattern in bumblebees. Studies involving tropical species, however, are still scarce. Here, we determined the mating frequency of queens of the tropical bumblebee species, Bombus wilmattae by using microsatellite genotyping based on a sample of nine colonies from Chiapas, Southern Mexico. A total of 204 workers were genotyped with microsatellite markers to infer the queen genotype and the number of males with which each queen had mated. Two of the nine queens were doubly mated and seven singly mated. In the colonies with the double-mated queens, the distribution of the patrilines was not even, resulting in effective mating frequencies of 1.34 and 1.70, respectively, and an average relatedness of g = 0.58 ± 0.06.