Ecology Of Bees Research Articles

From potential to practical: conserving bees in urban public green spaces

The documentation of many rare or declining bee species in urban green spaces has led to a recent focus on cities as conservation targets. However, for pollinator conservation to succeed long term, we argue that the opinions and values of local community members must be prioritized more explicitly. In our experience, conservation is difficult to achieve when the aesthetic and safety concerns of urban residents are not reconciled with the goals and habitat designs of conservation practitioners. Similarly, from a bee ecology perspective, many questions concerning optimal design and management practices for pollinator habitats in cities remain unresolved. It is our hope that frank discussion of the challenges associated with urban pollinator conservation in public green spaces will inspire thoughtful consideration of how best to implement new initiatives in cities.

Spatial ecology of a range-expanding bumble bee pollinator.

Molecular methods have greatly increased our understanding of the previously cryptic spatial ecology of bumble bees (Bombus spp.), with knowledge of the spatial ecology of these bees being central to conserving their essential pollination services. Bombus hypnorum, the Tree Bumble Bee, is unusual in that it has recently rapidly expanded its range, having colonized much of the UK mainland since 2001. However, the spatial ecology of B. hypnorum has not previously been investigated. To address this issue, and to investigate whether specific features of the spatial ecology of B. hypnorum are associated with its rapid range expansion, we used 14 microsatellite markers to estimate worker foraging distance, nest density, between‐year lineage survival rate and isolation by distance in a representative UK B. hypnorum population. After assigning workers to colonies based on full or half sibship, we estimated the mean colony‐specific worker foraging distance as 103.6 m, considerably less than values reported from most other bumble bee populations. Estimated nest density was notably high (2.56 and 0.72 colonies ha−1 in 2014 and 2015, respectively), estimated between‐year lineage survival rate was 0.07, and there was no evidence of fine‐scale isolation by distance. In addition, genotyping stored sperm dissected from sampled queens confirmed polyandry in this population (mean minimum mating frequency of 1.7 males per queen). Overall, our findings establish critical spatial ecological parameters and the mating system of this unusual bumble bee population and suggest that short worker foraging distances and high nest densities are associated with its rapid range expansion.

A Better Understanding of Bee Nutritional Ecology Is Needed to Optimize Conservation Strategies for Wild Bees-The Application of Ecological Stoichiometry.

The observed decline in wild bees may be connected to the decreasing diversity of flowering plants. Changes in floral composition shape nutrient availability in inhabited areas, and bee larvae need food rich in body-building nutrients to develop into adults. Adult food, mainly composed of energy-rich nectar, differs from larval food, mainly composed of pollen, and adult bees forage on different plant species for nectar and pollen. Defining bee-friendly plants based on the quantities of food produced, and on the visitation rates of adult pollinating insects leads to the planting of bee habitats with poor-quality food for larvae, which limits their growth and development, and negatively affects the population. Consequently, failing to understand the nutritional needs of wild bees may lead to unintended negative effects of conservation efforts. Ecological stoichiometry was developed to elucidate the nutritional constraints of organisms and their colonies, populations, and communities. Here, I discuss how applying ecological stoichiometry to the study of the nutritional ecology of wild bees would help fill the gaps in our understanding of bee biology. I present questions that should be answered in future studies to improve our knowledge of the nutritional ecology of wild bees, which could result in better conservation strategies.

A Social Ecology of Stingless Bees

Here we highlight two ontologically different modes of care and management of endemic stingless bees in Australia. While Indigenous Yolngu and backyard beekeepers both engage in caring for stingless bees, neither way of living with bees would classically be defined as ‘domestication’, yet bees are encompassed within the ‘home’, or domus. This requires a different perspective in relation to the kinds of multispecies connections between humans and other beings. We propose that the key difference between Aboriginal Australians hunting for sugarbag on country and beekeeping in the backyard is in the way bee populations are maintained and in the degree of ecological separation from the surrounding environment. For Yolngu the domus is the bush. Backyard beekeeping involves modes of care that separate bees from outside predators, pests and other detrimental elements, while the Yolngu relationship with bees is primarily concerned with maintaining the integrity of the surrounding ecology, or the homeland.

Assessment of nutritional resources quality from honeybees (<i>Apis mellifera adansonii</i>, L. 1758: Hymenoptera, Apidae) in three beekeeping sites of the Democratic Republic of Congo

Food products from honeybees are commonly used in Africa as in other parts of the world. The composition of bee related food is important for consumers but also to illustrate the feeding quality for the bees. The present study was aimed at assessing the quality of bee bread and honeys for the survival of A. mellifera adansonii , L. 1758 in the DRC. Several environments were selected, namely a rainforest in Kisangani, a savannah in Kavwaya and a restored forest in Mampu. Bee breads were assessed according to their richness in proteins and essential amino acids. Honeys were evaluated considering the water content, the sugar rates, the amount of 5-(hydroxymethyl)-2-furaldehyde (HMF), the acidity (pH) and conductivity. The average content of protein from pollens collected in the DRC was 14.11 ± 5.27%. The protein content was low compared with the food needs of bees (and to the European breeds). No significant difference was observed between Kisangani, Mampu and Kavwaya in terms of protein content of beebread (P ≥ 0.05). The concentrations of ten essential amino acids for bees were within the optimum range of food needs for honeybees (set for European bee races). Beebreads collected in the rainforest of Kisangani were significantly richer in isoleucine, leucine, valine, arginine, lysine and phenylalanine than those from the savannah of Kavwaya. However, beebreads harvested in Kisangani were not significantly different from those from the replanted Mampu forest. The analysis of honey samples revealed that the Congolese honeys had good nutritional quality for bees. Indeed, reducing sugar content of the collected samples ranged from 63.40 to 73.80%, the content of sucrose ranged from 0.30 to 1.90%, the content of water varied from 16.80 to 22.00%, the pH of the analyzed honey samples ranged from 4.22 to 4.53. The average of the electrical conductivity was 47.74 ± 13.93 μS/cm and the concentration of HMF varied from 1.75 to 31.38 mg HMF/kg of honey. The honeys collected in the rainforest of Kisangani were significantly richer in minerals and moisture than those from the savannah of Kavwaya (P <0.05). However, the honeys collected in the last savannah were richer in sucrose and HMF than those collected in the Kisangani rainforest and the restored forest of Mampu (P <0.05). These results would only be applied for the time at which the samples were collected (January-February) but are an interesting data set for further use of bee related product in DRC. Keywords : Apis mellifera adansonii , honey, bee bread, quality, nutrition, bee ecology, DRC.

Behavioral Repertoires and Interactions between Apis mellifera (Hymenoptera: Apidae) and the Native Bee Lithurgus littoralis (Hymenoptera: Megachilidae) in Flowers of Opuntia huajuapensis (Cactaceae) in the Tehuacán Desert

The introduction of the honey bee, Apis mellifera L. (Hymenoptera: Apidae), into the arid environments of Mexico has affected the behavioral ecology of native bees. We described the behavioral repertoire and interactions between A. mellifera and the native bee Lithurgus littoralis Cockerell (Hymenoptera: Megachilidae) on Opuntia huajuapensis Bravo (Cactaceae) flowers in a semiarid environment. We filmed the bees in 150 cactus flowers to obtain the diversity of behaviors and their durations and thereby quantify the interactions. The behavior accumulation curve (Clench model) showed differences in the behavioral repertoire between the 2 bee species and between the sexes of L. littoralis. We found that A. mellifera and L. littoralis females invested more time in feeding behavior than L. littoralis males and recorded a wider repertoire of agonistic behaviors in male compared with female bees. Native male bees often perched in flowers and were inactive for long periods. The results indicate a possible interference competition between native and non-native bee species that are visiting the flowers of O. huajuapensis.

Big city Bombus: using natural history and land-use history to find significant environmental drivers in bumble-bee declines in urban development.

Native bee populations are critical sources of pollination. Unfortunately, native bees are declining in abundance and diversity. Much of this decline comes from human land-use change. While the effects of large-scale agriculture on native bees are relatively well understood, the effects of urban development are less clear. Understanding urbanity's effect on native bees requires consideration of specific characteristics of both particular bee species and their urban landscape. We surveyed bumble-bee (Bombus spp.) abundance and diversity in gardens across multiple urban centres in southeastern Michigan. There are significant declines in Bombus abundance and diversity associated with urban development when measured on scales in-line with Bombus flight ability. These declines are entirely driven by declines in females; males showed no response to urbanization. We hypothesize that this is owing to differing foraging strategies between the sexes, and it suggests reduced Bombus colony density in more urban areas. While urbanity reduced Bombus prevalence, results in Detroit imply that ‘shrinking cities’ potentially offer unique urban paradigms that must be considered when studying wild bee ecology. Results show previously unidentified differences in the effects of urbanity on female and male bumble-bee populations and suggest that urban landscapes can be managed to support native bee conservation.

Chemical Ecology of Stingless Bees.

Stingless bees (Hymenoptera, Apidae: Meliponini) represent a highly diverse group of social bees confined to the world's tropics and subtropics. They show a striking diversity of structural and behavioral adaptations and are important pollinators of tropical plants. Despite their diversity and functional importance, their ecology, and especially chemical ecology, has received relatively little attention, particularly compared to their relative the honeybee, Apis mellifera. Here, I review various aspects of the chemical ecology of stingless bees, from communication over resource allocation to defense. I list examples in which functions of specific compounds (or compound groups) have been demonstrated by behavioral experiments, and show that many aspects (e.g., queen-worker interactions, host-parasite interactions, neuronal processing etc.) remain little studied. This review further reveals that the vast majority of studies on the chemical ecology of stingless bees have been conducted in the New World, whereas studies on Old World stingless bees are still comparatively rare. Given the diversity of species, behaviors and, apparently, chemical compounds used, I suggest that stingless bees provide an ideal subject for studying how functional context and the need for species specificity may interact to shape pheromone diversification in social insects.

Using the waggle dance to determine the spatial ecology of honey bees during commercial crop pollination

Managed honey bees play an important role in global crop pollination. Maximizing their potential is likely to be of increasing importance to the global human supply. We explored the potential of waggle dance data to determine the spatial ecology of honey bees sited in a crop under commercial pollination. Over two springs, we video recorded and then decoded 834 waggle dances from colonies located in two apple and pear farms in Kent, U.K. We also obtained pollen samples from returning foragers and quantified the insects visiting apple and pear flowers. The vast majority (84%) of dances were for locations outside of the orchards in which our colonies were located. Accounting for the distance of orchards and oilseed rape fields from the study colonies, the amount of foraging per hectare in oilseed rape fields was greater than in orchards. The results of the present study indicate that maximizing the pollination services of managed honey bee colonies requires an landscape level approach that takes into account farm and foraging scale, as well as competing floral sources. The data also suggest that oilseed rape is a significant competitor to apple and pear flowers for honey bee visits.

Integrating intraspecific variation in community ecology unifies theories on body size shifts along climatic gradients

Summary Physiological and energetic mechanisms have been proposed to constrain body sizes of organisms along climatic gradients; however, these provide contrasting predictions. While Bergmann's rule predicts increases in body sizes in cooler climates resulting from physiological constraints, energy‐based community assembly rules suggest declines in the mean body size of species caused by increased extinction probabilities for large‐bodied species in low‐energy habitats. We tested these contrasting hypotheses by quantifying trait distributions in bee communities along a 3·6‐km elevational gradient at Mt. Kilimanjaro. Traditionally, intra‐ and interspecific trait shifts along environmental gradients have been investigated in isolation. However, a surge of theoretical approaches and studies on plants demonstrated that the explicit integration of trait variation among and within species can be essential for identifying the mechanisms that shape traits and related ecosystem functions along environmental gradients. We therefore studied variation in body size and related morphological traits at both the intra‐ and interspecific level. We found support for both physiological constraints and energy‐based community assembly rules as drivers of trait distribution in bee communities along elevational gradients, which, however, affected different levels of biotic organization, that is the population and community level. While the number of bee species with large body sizes declined with elevation, individuals within species became on average larger, resulting in contrasting trends in morphometric parameters at the community versus population level. Furthermore, body size within bee communities became less variable at higher elevations, largely as a result of a non‐random, directive loss of species, but paralleled by a decline in intraspecific variance, suggesting intensified filtering effects with increasing elevation. Similar patterns were found for other functional traits related to the foraging ecology of bees (tongue length, relative forewing length). We conclude that along climatic gradients both physiological and energetic constraints shape trait distributions of pollinators, but at different levels of biological organization. A lay summary is available for this article.

Distribution and ecology of bees on the Polish Baltic coast (Hymenoptera, Apoidea, Apiformes)

Abstract The present study provides data on the distribution of 128 bee species on the Polish Baltic coast. This brings the total number of species of Apiformes in this region to 164, including those that I reported earlier. The bee fauna of the Polish coast is characterized by a very high proportion of bumblebees and cuckoo bees (locally up to 70-80% of the total catch), and the dominant proportion of Megachilidae, especially Megachile species. The species diversity and dominance structure of the Apiformes differ between the western coast (a very high proportion of bumblebees) and the eastern coast (a large number of dominant species). These results confirm my earlier hypothesis regarding the maritime-continental gradient of bumblebee abundance, indicating that the densities of these insects are higher in NW Poland. This study is the first to assess bee densities on coastal dunes in Poland.

Wild bee pollination networks in northern New England

Conserving and maintaining a diverse assemblage of wild bees is essential for a healthy and functioning ecosystem, as species are uniquely evolved to deliver specific plant–pollination requirements. Understanding the biology and ecology of bees in poorly studied regions is the first step towards conservation. Detailed surveys in New Hampshire reveal a broad diversity of 118 species of wild bees in different guilds and habitats including 17 bee species representing new state records. Network analyses reveal a complex community structure and relatively poorly connected plant–pollinator associations, thus species may be susceptible to disturbance. Phenological analyses document that at least one representative of five native bee families was present throughout the foraging season and both abundance and diversity were highest in June and July. This study provides important baseline information on bee abundance, diversity, phenology, and host plant associations necessary for future conservation efforts.

USBombus, a database of contemporary survey data for North American Bumble Bees (Hymenoptera, Apidae, Bombus) distributed in the United States.

BackgroundBumble bees (Hymenoptera: Apidae, Bombus) are pollinators of wild and economically important flowering plants. However, at least four bumble bee species have declined significantly in population abundance and geographic range relative to historic estimates, and one species is possibly extinct. While a wealth of historic data is now available for many of the North American species found to be in decline in online databases, systematic survey data of stable species is still not publically available. The availability of contemporary survey data is critically important for the future monitoring of wild bumble bee populations. Without such data, the ability to ascertain the conservation status of bumble bees in the United States will remain challenging.New informationThis paper describes USBombus, a large database that represents the outcomes of one of the largest standardized surveys of bumble bee pollinators (Hymenoptera, Apidae, Bombus) globally. The motivation to collect live bumble bees across the United States was to examine the decline and conservation status of Bombus affinis, B. occidentalis, B. pensylvanicus, and B. terricola. Prior to our national survey of bumble bees in the United States from 2007 to 2010, there have only been regional accounts of bumble bee abundance and richness. In addition to surveying declining bumble bees, we also collected and documented a diversity of co-occuring bumble bees. However we have not yet completely reported their distribution and diversity onto a public online platform. Now, for the first time, we report the geographic distribution of bumble bees reported to be in decline (Cameron et al. 2011), as well as bumble bees that appeared to be stable on a large geographic scale in the United States (not in decline). In this database we report a total of 17,930 adult occurrence records across 397 locations and 39 species of Bombus detected in our national survey. We summarize their abundance and distribution across the United States and association to different ecoregions. The geospatial coverage of the dataset extends across 41 of the 50 US states, and from 0 to 3500 m a.s.l. Authors and respective field crews spent a total of 512 hours surveying bumble bees from 2007 to 2010. The dataset was developed using SQL server 2008 r2. For each specimen, the following information is generally provided: species, name, sex, caste, temporal and geospatial details, Cartesian coordinates, data collector(s), and when available, host plants. This database has already proven useful for a variety of studies on bumble bee ecology and conservation. However it is not publicly available. Considering the value of pollinators in agriculture and wild ecosystems, this large database of bumble bees will likely prove useful for investigations of the effects of anthropogenic activities on pollinator community composition and conservation status.

Within-Colony Variation in the Immunocompetency of Managed and Feral Honey Bees (Apis mellifera L.) in Different Urban Landscapes.

Urbanization has the potential to dramatically affect insect populations worldwide, although its effects on pollinator populations are just beginning to be understood. We compared the immunocompetency of honey bees sampled from feral (wild-living) and managed (beekeeper-owned) honey bee colonies. We sampled foragers from feral and managed colonies in rural, suburban, and urban landscapes in and around Raleigh, NC, USA. We then analyzed adult workers using two standard bioassays for insect immune function (encapsulation response and phenoloxidase activity). We found that there was far more variation within colonies for encapsulation response or phenoloxidase activity than among rural to urban landscapes, and we did not observe any significant difference in immune response between feral and managed bees. These findings suggest that social pollinators, like honey bees, may be sufficiently robust or variable in their immune responses to obscure any subtle effects of urbanization. Additional studies of immune physiology and disease ecology of social and solitary bees in urban, suburban, and natural ecosystems will provide insights into the relative effects of changing urban environments on several important factors that influence pollinator productivity and health.

Floral Resources Used by Honey Bees in Agricultural Landscapes

Honey bees are polylectic insects able to forage on many flower species in order to provide enough abundant and diverse food for the colony. However, land use changes and agricultural intensification have disrupted the floral availability in agricultural landscapes. Here, we investigated empirically the floral resources used by honey bees in an intensive cereal farming system. We found that honey bees foraged on a wide diversity of flowers throughout the season, mainly derived from trees and weeds. When mass-flowering crops are available, honey bees use them. However, mass-flowering crops are highly seasonal and induce a supply depletion between two peak periods, which precisely matches the peak of demographic growth of bee colonies. Our empirical results support the Agri-Environmental Schemes intended to promote honey bees and beekeeping sustainability. The Long-Term Ecological Research “Zone Atelier Plaine et Val de Sèvre” in central western France (46°23' N, 0°41' W) hosts a study about bee ecology since 2008 through the ECOBEE platform. Local agricultural intensification has led to an intensive cereal farming system, with mass-flowering crops such as rapeseed (Brassica napus) and sunflower (Helianthus annuus). In this environmental context, we studied the foraging behavior of honey bees throughout the beekeeping season with 250 monitored colonies. Photo by Christophe Maitre/INRA. We fitted beehives with pollen grid traps at their entrance in order to sample the pollen loads harvested by foragers. This photo shows the variability of colors in collected pollen loads, witnessing the diversity of flowers visited by honey bees. In our intensive agricultural landscape, honey bees forage on a wide diversity of flowers for their pollen intakes (about 230 species). Photo by Thierry Tamic. We identified the botanical origin of pollen loads by palynological analyses. We present here the pollen grains of the three dominant floral resources used by honey bees in intensive cereal farming system, i.e. two crops, maize (Zea mays, the big pollen grain at center), and sunflower (the smaller echinate pollen grains), and a weed species, poppy (Papaver rhoeas, bottom right). The changing dynamic of crop flower availability disturbs the seasonal pattern of pollen intake with pollen supply depletion in spring. Surprisingly, poppy is a dominant species foraged for pollen in similar proportion than maize and sunflower. Poppy is especially collected during the period of pollen supply depletion, indicating a major role of weeds for honey bee diet in intensive cereal farming systems. Photos by Thierry Tamic. Honey bees forage on a wide diversity of flowers in intensive agricultural landscapes. For example, we present here four plant species foraged by honey bees for pollen and/or nectar intakes, i.e. Prunus spinosa (top left) a woody plant species foraged in April; Bellis perennis (top right) a herbaceous plant species foraged throughout the whole season; Malva sylvestris (bottom left) a herbaceous plant species foraged in July; and Phacelia tanacetifolia (bottom right) a crop foraged in May. Semi-natural habitats (i.e. grasslands, forest, and hedgerows) and weeds need to be considered for bee conservation in agricultural landscapes because they provide highly diverse and continuous floral resources throughout the season. Photos top left and bottom left by Thierry Tamic, and photos top right and bottom right by Fabrice Requier. These photographs illustrate the article “Honey bee diet in intensive farmland habitats reveals an unexpectedly high flower richness and a major role of weeds” by Fabrice Requier, Jean-François Odoux, Thierry Tamic, Nathalie Moreau, Mickaël Henry, Axel Decourtye and Vincent Bretagnolle, published in Ecological Applications 25(4):881–890, June 2015. http://dx.doi.org/10.1890/14-1011.1

Molecular tools and bumble bees: revealing hidden details of ecology and evolution in a model system.

Bumble bees are a longstanding model system for studies on behaviour, ecology and evolution, due to their well-studied social lifestyle, invaluable role as wild and managed pollinators, and ubiquity and diversity across temperate ecosystems. Yet despite their importance, many aspects of bumble bee biology have remained enigmatic until the rise of the genetic and, more recently, genomic eras. Here, we review and synthesize new insights into the ecology, evolution and behaviour of bumble bees that have been gained using modern genetic and genomic techniques. Special emphasis is placed on four areas of bumble bee biology: the evolution of eusociality in this group, population-level processes, large-scale evolutionary relationships and patterns, and immunity and resistance to pesticides. We close with a prospective on the future of bumble bee genomics research, as this rapidly advancing field has the potential to further revolutionize our understanding of bumble bees, particularly in regard to adaptation and resilience. Worldwide, many bumble bee populations are in decline. As such, throughout the review, connections are drawn between new molecular insights into bumble bees and our understanding of the causal factors involved in their decline. Ongoing and potential applications to bumble bee management and conservation are also included to demonstrate how genetics- and genomics-enabled research aids in the preservation of this threatened group.

Pollen Wasps and Flowers in Southern Africa and Wasps and Bees in Southern AfricaPollen Wasps and Flowers in Southern Africa by S.K. Gess &amp; F.W. Gess . SANBI Biodiversity Series 18. South African National Biodiversity Institute, Pretoria. 2010. 147 pp. Price R160 (paperback). ISBN 978-1-919976-60-0.Wasps and Bees in Southern Africa by S.K. Gess &amp; F.W. Gess . SANBI Biodiversity Series

A formidable team, Sarah and Fred Gess spent in excess of 40 years patiently observing the lives of wasps and bees on numerous extended field trips, mostly into the more arid western areas of southern Africa. Their passion for insects, combined with careful observation and dedicated documentation of data facilitated the elucidation of the intricate nature of the ecology and behaviour of Africa's wasps and bees. With their complementary expertise and skills, Fred and Sarah compiled a comprehensive knowledge base that will serve the scientific and conservation communities well into the future. The culminated data are now available in two excellent SANBI publications, both richly illustrated with colour photographs and containing a wealth of biological information, providing valuable baseline data for future conservation assessments.

Nesting ecology of stingless bees and potential threats to their survival within selected landscapes in the northern Volta region of Ghana

Stingless bees are key insects in the tropics, both as pollinators of crops and as contributors to the maintenance of floral diversity through pollination of wild plants. This study investigated the nesting ecology and threats to three stingless bee species: Meliponula bocandei (Spinola), Meliponula ferruginea (Lepeletier) and Dactylurina staudingeri (Gribodo) in three landscapes characterized as forest with logging and wild honey hunting; farmlands that experience annual wild fires and a national park. The study was carried out in July 2011 and February 2012. A total of 93 stingless bee nests were found in 48 ha (density 1.9 nests per ha), 81% in tree cavities and 19% in deserted termite mounds and in the ground. M. ferruginea was the only species using deserted termite mounds (seventeen nests) and in the ground (1 nest). Although tree size (diameter at breast height, DBH >15 cm) and density of large tree were important for nest site selection, there was no influence of tree species. M. bocandei may be restricted in choice of nest site in farmland areas by the absence of trees. Reduced availability of trees in agricultural landscape together with bush burning and wild honey collecting is the main threats to stingless bees survival and abundance which need to be addressed for their successful conservation in Ghana. Resume Les abeilles sans dard sont des insectes cles sous les Tropiques, elles pollinisent les cultures et contribuent a la preservation de la diversite florale par la pollinisation de plantes sauvages. Cette etude a analyse l’ecologie de nidification et les menaces qui pesent sur trois especes d'abeilles sans dard, Meliponula bocandei (Spinola), Meliponula ferruginea (Lepeletier) et Dactylurina staudingeri (Gribodo), dans trois paysages caracterises comme suit : une foret avec exploitation forestiere et recolte de miel sauvage ; une exploitation agricole subissant des feux chaque annee et ; un parc national. L’etude a eu lieu entre juillet 2011 et fevrier 2012. Au total, 93 nids d'abeilles sans dard ont ete trouves sur 48 ha (densite : 1,9 nid/ha), 81% etant dans des cavites d'arbres, et 19% dans des termitieres desertees et dans le sol. M. ferruginea etait la seule espece utilisant des termitieres desertees (17 nids) et le sol (un nid). La taille des arbres (dbh > 15 cm) et la densite des grands arbres etaient importantes pour la selection de l'endroit du nid, mais l'espece des arbres n'avait pas d'influence. M. bocandei pourrait etre limite dans le choix d'un endroit pour le nid dans les exploitations agricoles depourvues d'arbres. La disponibilite restreinte d'arbres dans le paysage agricole, et aussi les feux de brousse et la recolte de miel sauvage, sont les menaces principales pour la survie et l'abondance des abeilles sans dard et ces menaces doivent etre ecartees pour assurer leur conservation au Ghana.

Long-term ecology of orchid bees in an urban forest remnant

Ecological studies lasting more than 1 or 2 years are not particularly common anywhere and in any taxonomic group. Ecological studies in orchid bees (Hymenoptera: Apidae) are not an exception and have focused on short-term scale. Long-term studies have been mostly neglected up to date. Orchid-bee males were attracted to five different scent baits in the same site every other year during a seven-year span, from 1997 to 2004, in an urban forest remnant, totaling four full years of samplings in between. In total, we captured 2188 bees from 14 species. Species diversity, evenness, and richness remained remarkably stable among years. The stability index, sensu Wolda, for the composite community revealed to be one of the highest ever recorded for insect communities. Our results suggest that orchid-bee populations may remain remarkably stable over the years even in a small (≈200 ha) area immersed in a metropolitan (≈3,000,000 inhabitants) matrix and that these urban areas should not be neglected in conservation efforts, since they seem to maintain viable populations of these important pollinators over time.

Mutualism and manipulation in Hadza–honeyguide interactions

We investigated the ecology and evolution of interspecific cooperation between the Greater Honeyguide bird, Indicator indicator, and human hunter-gatherers, the Hadza of northern Tanzania. We found that honeyguides increased the Hadza's rate of finding bee nests by 560%, and that the birds led men to significantly higher yielding nests than those found without honeyguides. We estimate that 8–10% of the Hadza's total diet was acquired with the help of honeyguides. Contrary to most depictions of the human-honeyguide relationship, the Hadza did not actively repay honeyguides, but instead, hid, buried, and burned honeycomb, with the intent of keeping the bird hungry and thus more likely to guide again. Such manipulative behavior attests to the importance of social intelligence in hunter-gatherer foraging strategies. We present an evolutionary model for human-honeyguide interactions guided by the behavioral ecology of bees, non-human primates, and hunter-gatherers.