Exotic Bee Research Articles

The explosive pollination mechanism in Papilionoideae (Leguminosae): an analysis with three Desmodium species

In the papilionaceous flowers with explosive pollination mechanism, the androecium and the gynoecium are subjected to great pressure in the keel. It has been suggested that at the first visit nearly all pollen grains are released and that the floral parts do not return to their original positions; this would be a cue for pollinators to avoid activated flowers. The dependence on the pollinators suggests that explosive flowers will not produce fruits if the mechanism is not activated. In this paper, we have tested these ideas studying the reproductive biology of three Desmodium species, D. incanum, D. subsericium and D. uncinatum. Specifically, we studied the floral traits, reproductive system, pollination mechanism and floral visitors, for the three species. The results indicated that the keel and the wings play a key role in the activation of the explosive mechanism. The three species have a secondary pollen presentation, diurnal flowers, and a short floral cycle. According to the results, all the species studied were self-compatible, with two species producing fruits by autonomous self-pollination. Desmodium flowers were visited and activated by native and exotic bee species. During the first visit nearly all the pollen was released; after that, new visits were low or null. Our results indicated that the activation of the mechanism is not essential for the production of fruits, that explosive flowers are visited only once and that the changes in the positions of the floral parts are the cues that keep pollinators away from the flowers with activated mechanism.

Extremely reduced sexual reproduction in the clonal cactus Echinopsis thelegona

Sexual and asexual reproduction may occur simultaneously in some plant species. Under certain environmental conditions asexual reproduction is predominant, which generates ecological consequences on sexual fecundity. In this context, we studied the reproductive ecology of the creeping clonal cactus Echinopsis thelegona in La Bodega (Salta, Argentina), where low fruit and seed production was preliminarily observed. Specifically, we studied the flower availability, fruit and seed production, reproductive system, floral visitors and effects of neighbor ramets on reproductive success. The number of available flowers per day was low, and fruit production was low or null as well. Echinopsis thelegona is self-incompatible. Although its flowers have sphingophilous traits, we did not find evidence of moths visiting them. Only native and exotic bees visited the flowers of this species, though with a low number of visits. Therefore, nocturnal visitors were not registered as pollinators of E. thelegona, perhaps because of their low local abundances. On the other hand, bees behaved as inefficient pollinators of E. thelegona due to their foraging behavior, which moves pollen within individuals. A pollen-addition experiment revealed that there is no fruit production at short distances among ramets. Therefore, the combination of self-incompatibility, low flower production and low local abundance of pollinators could account for the low fruit production observed in this species. This finding suggests that populations of E. thelegona persist by clonality and that they tend toward the loss of sexuality.

Modelling honey bee queen mating as a measure of feral colony density

Robust estimates of feral and wild honey bee (Apis mellifera) colony densities are essential for the understanding of the role of honey bees in an ecosystem, and for planning responses to an incursion of an exotic honey bee disease or pest. New genetic methods make it possible to identify the number of feral colonies with which a test queen mates. We present an agent-based model of the spatial process of honey bee mating that describes the relationship between feral colony densities and the number of unique colonies with which a queen mates. This model incorporates random, aggregated and overdispersed spatial distributions of feral colonies and drone congregation areas. We model different densities of feral colonies and drone congregation areas with various numbers of test queens and determine the range of counts of matings with drones from unique colonies. The model shows that the range of counts for a given set of parameters is consistent with a Poisson distribution, and that the most significant explanatory variable is density of the feral colonies. The results obtained reveal that 10 or more test queens may be needed in field studies to resolve order of magnitude differences in feral colony densities. We conclude that the new genetic methods provide a powerful tool for making indirect inferences about feral colony densities, so long as the field survey results are treated as outcomes of a stochastic spatial process.

Occurrence of the exotic leafcutter bee Megachile (Eutricharaea) concinna (Hymenoptera: Megachilidae) in southern South America. An accidental introduction?

SummaryHere we report for the first time the presence of the exotic leafcutter bee Megachile (Eutricharaea) concinna in South America, based on specimens collected in the northeast part of Buenos Aires province, Argentina. We believe that M. concinna accidentally entered the country probably together with the introduction of M. rotundata to different regions of the country for commercial purposes since the 1970's. A diagnosis, illustrations, flowers records, and nesting data are given.

Generalist Bee Species on Brazilian Bee-Plant Interaction Networks

Determining bee and plant interactions has an important role on understanding general biology of bee species as well as the potential pollinating relationship between them. Bee surveys have been conducted in Brazil since the end of the 1960s. Most of them applied standardized methods and had identified the plant species where the bees were collected. To analyze the most generalist bees on Brazilian surveys, we built a matrix of bee-plant interactions. We estimated the most generalist bees determining the three bee species of each surveyed locality that presented the highest number of interactions. We found 47 localities and 39 species of bees. Most of them belong to Apidae (31 species) and Halictidae (6) families and to Meliponini (14) and Xylocopini (6) tribes. However, most of the surveys presentedApis melliferaand/orTrigona spinipesas the most generalist species.Apis melliferais an exotic bee species andTrigona spinipes, a native species, is also widespread and presents broad diet breath and high number of individuals per colony.

Contrasting bee pollination in two co-occurring distylic species of Cordia (Cordiaceae, Boraginales) in the Brazilian semi-arid Caatinga: generalist in C. globosa vs. specialist in C. leucocephala

In this study we compare the reproductive biology of Cordia globosa and C. leucocephala (Cordiaceae, Boraginales; formerly referred to Boraginaceae) to understand the functioning of the floral morphs and the relations with their effective pollinators. The species are synchronopatric, distylic, and self-incompatible. Though they share melittophilous traits, the main visitor and pollinator of C. globosa was the generalist and exotic bee Apis mellifera, while the only one of C. leucocephala was the oligoletic bee Ceblurgus longipalpis. These two latter species are restricted to the Caatinga of NE Brazil, contrasting with the wide distribution of Cordia globosa. While the fruit-set for C. globosa was high, independently if the pollen donor/stigma receptor was a pin (long-styled) or thrum (short-styled) individual, in C. leucocephala the fruit-set was low and occurred only when a thrum individual was the pollen donor. This raises the possibility of this species moving towards dioecy. The high natural fruit-set of C. globosa confirms the generalist bee as its effective pollinator. The low fruit-set after manual crosses in C. leucocephala may be due to low pollen viability. Additionally, the low natural fruit-set (two times lower than after crosses) may be related with the foraging behavior of the specialist pollinator.

Contrasting bee foraging in response to resource scale and local habitat management

It is hypothesized that two main factors drive the foraging patterns of native and exotic species: food resource availability and habitat composition. These factors are particularly relevant for native bees and exotic honeybees, essential crop pollinators that are sensitive to floral resources and habitat management, and that have recently exhibited alarming population declines. Mechanisms driving native and exotic bee foraging patterns may critically depend on floral resource availability and habitat composition, yet the impacts of these factors on bee foraging have never been simultaneously analyzed. In a coffee producing region in southern Mexico, we investigated the influence of coffee floral resource levels and habitat management on native and exotic bee foraging. We measured the amount of flowering coffee available at multiple spatial scales within two distinct agroforestry habitat types (high‐shade and low‐shade coffee) and recorded visits to coffee flowers, documenting bee species, visit duration and visit frequency. We observed a significantly greater number of visits in high‐shade coffee habitats than in low‐shade coffee habitats for both native and exotic bees. In high‐shade coffee habitats, native solitary bee and native social bee visitation decreased significantly in response to increasing floral resource availability, exhibiting a ‘dilution effect’ at the smallest spatial scale. In contrast, in low‐shade coffee habitats, Africanized honeybees exhibited a ‘concentration effect’, increasing visitation significantly in response to increasing floral resource availability at the largest spatial scale. This study is the first to show that foraging patterns of native bees and exotic honeybees contrast in response to floral resource level and scale and that this response is mediated by the vegetation management of the local habitat.

Contrasting foraging patterns for Africanized honeybees, native bees and native wasps in a tropical agroforestry landscape

Abstract:Ecological and temporal factors can influence animal foraging patterns and may obscure our understanding of how native and exotic species interact. To understand how such factors affect foraging, the visitation of native and exotic bees and wasps was observed at nectar feeders within Mexican agroforestry systems, while documenting (1) vegetation management (low-shade vs. high-shade coffee), (2) light and floral resource levels and (3) recruiting ability, as measured by the change in visitation between two consecutive experimental days. On day one, Africanized honeybee visitation was significantly greater in low-shade habitats, and native solitary bee abundance was significantly greater in high-shade habitats, while native social bee and solitary wasp visitation were not significantly different between habitat types. After 24 h, Africanized honeybee visitation increased significantly in both habitat types, while native social bee visitation increased significantly only in high-shade coffee. In contrast, native solitary bee and native solitary wasp visitation decreased in both habitat types. Overall, this study reveals that Africanized honeybees exhibit only initial foraging preference for low-shade habitats, while native bees exhibit both initial and delayed recruitment-based foraging preferences for high-shade habitats.

Relative pollination effectiveness of floral visitors of Pitcairnia angustifolia (Bromeliaceae)

The effectiveness of flower visitors as pollinators will determine their potential role as selective agents on flower traits. Pitcairnia angustifolia has floral characters that would fit pollination by long-billed hummingbirds, and they should be the most effective pollinators for this plant. To test this prediction, we characterized the behavior of visitors toward flowers and their pollination effectiveness. Coereba flaveola (bananaquits) was the most frequent flower visitor and acted as a primary nectar robber; however, they pollinated incidentally and deposited pollen on stigmas. The endemic short-billed hummingbird Chlorostilbon maugaeus behaved as a secondary robber and did not pollinate flowers. As expected, the long-billed hummingbird, Anthracothorax viridis, was the most efficient visitor in terms of pollen deposition; however, it was the least frequent flower visitor. Introduced Apis mellifera (honeybees) were second in efficiency at depositing pollen and performed one third of the flower visits. Estimates of the expected rate of pollen deposition by each pollinator did not identify a single most effective pollinator. For P. angustifolia at least three flower visitors including an exotic bee and a nectar robber may be equally important to reproductive success. While these results limit our ability to make predictions on the role of hummingbird-pollination on current flower evolution, they do suggest the potential for pollination redundancy among flower visitors for P. angustifolia populations.

Effects of Introduced Bees on Native Ecosystems

▪ Abstract Bees are generally regarded as beneficial insects for their role in pollination, and in the case of the honeybee Apis mellifera, for production of honey. As a result several bee species have been introduced to countries far beyond their home range, including A. mellifera, bumblebees (Bombus sp.), the alfalfa leafcutter bee Megachile rotundata, and various other solitary species. Possible negative consequences of these introductions include: competition with native pollinators for floral resources; competition for nest sites; co-introduction of natural enemies, particularly pathogens that may infect native organisms; pollination of exotic weeds; and disruption of pollination of native plants. For most exotic bee species little or nothing is known of these possible effects. Research to date has focused mainly on A. mellifera, and has largely been concerned with detecting competition with native flower visitors. Considerable circumstantial evidence has accrued that competition does occur, but no experiment has clearly demonstrated long-term reductions in populations of native organisms. Most researchers agree that this probably reflects the difficulty of carrying out convincing studies of competition between such mobile organisms, rather than a genuine absence of competitive effects. Effects on seed set of exotic weeds are easier to demonstrate. Exotic bees often exhibit marked preferences for visiting flowers of exotic plants. For example, in Australia and New Zealand many weeds from Europe are now visited by European honeybees and bumblebees. Introduced bees are primary pollinators of a number of serious weeds. Negative impacts of exotic bees need to be carefully assessed before further introductions are carried out.

Pollination of the invasive exotic shrub Lupinus arboreus (Fabaceae) by introduced bees in Tasmania

Exotic plant invasions threaten ecological communities world-wide. Some species are limited by a lack of suitable pollinators, but the introduction of exotic pollinators can facilitate rapid spread. In Tasmania, where many non-native plants are naturalised, exotic honeybees (Apis mellifera) and bumblebees (Bombus terrestris) have become established. We determined how these species affect the pollination of Lupinus arboreus, an invasive, nitrogen-fixing shrub, which is rarely visited by native pollinators. The proportion of flowers setting seed and the number of ovules fertilised per flower were positively related to the visitation rates of both exotic bee species. There was no effect of bee visitation rates on the proportion of seeds aborted prior to maturity, possibly due to post-fertilisation environmental constraints. We conclude that the spread of B. terrestris may not alter the fecundity of L. arboreus because of the pollination service provided by A. mellifera, and discuss potential interactions between these two bee species.

Do exotic bumblebees and honeybees compete with native flower-visiting insects in Tasmania?

Honeybees, Apis mellifera, have been introduced by man throughout the globe. More recently, other bee species including various bumblebees (Bombus spp.) have been introduced to several new regions. Here we examine the impacts of honeybees and the bumblebee, Bombus terrestris, on native flower-visiting insects in Tasmania. To assess whether native insects have lower abundance or are excluded in areas that have been colonised by exotic bees, we quantified the abundance, diversity and floral preferences of flower-visiting insects at sites where bumblebees and honeybees were present, and compared them to sites where they were absent. This was achieved by hand searches at 67 sites, and by deploying sticky traps at 122 sites. Honeybees were by far the most abundant bee species overall, and dominated the bee fauna at most sites. There was considerable niche overlap between honeybees, bumblebees and native bees in terms of the flowers that they visited. Sites where bumblebees were established had similar species richness, diversity and abundance of native flower-visiting insects compared to sites where bumblebees were absent. In contrast, native bees were more than three times more abundant at the few sites where honeybees were absent, compared to those where they were present. Our results are suggestive of competition between honeybees and native bees, but exclusion experiments are needed to provide a definitive test.

An improved method for the detection and presumptive identification of Paenibacillus larvae subsp. larvae spores in honey

SUMMARYOne of the most important diseases that attacks honey bees (Apis spp.) in the larval stage is American foulbrood (AFB), for which Paenibacillus larvae subsp. larvae is the causative agent. American foulbrood is considered an exotic bee disease in Brazil because it has not yet been detected in the country. Feeding honey containing spores of P. I. larvae to bee larvae can transmit AFB, hence imported honey could spread this disease to Brazil. Since the disease is widely spread in some Latin American countries, including one bordering Brazil, the Brazilian authorities, and beekeepers, are concerned about the risk of introduction of AFB to Brazil. Accordingly, an improved method of detecting spores of P. I. larvae in honey has been developed. The method is based on concentrating spores by centrifugation, inactivating vegetative cells and then inoculating onto a newly developed selective solid medium: Paenibacillus larvae subsp. larvae agar (PLA). Suspect colonies are then selected and cultures are confirmed by biochemical identification. The method was able to detect less than 10 viable spores of P. I. larvae per 1 ml of honey.

Does the recently introduced bumblebee Bombus terrestris (Apidae) threaten Australian ecosystems?

Abstract Native vegetation near Hobart in Tasmania was investigated to determine whether it was being invaded by the recently introduced large earth bumblebee, Bombus terrestris (Linnaeus, 1758). This species was found to be established in high numbers in a variety of vegetation types from coastal heath, through sclerophyll forest, and subalpine shrubberies up to an altitude of 1100 m. Hence, it has the potential to spread through much of Tasmania and temperate, mesic regions of mainland Australia. It is highly polylectic, foraging on at least 66 native plant species from 21 families. While the most heavily visited species produced abundant nectar, the lack of pre‐dation on this species also allowed it to forage economically on small flowers in clusters. This foraging profile overlapped with those of all anthophilous insect families, all bee subgenera, and all species of nectarivorous birds which were encountered. Therefore, B. terrestris has the potential to compete with most native anthophiles and commercial honeybees. As it forages from some plant taxa which are not visited by the European honeybee, Apis mellifera Linnaeus, 1758, this species is impacting on plant‐pollinator relationships which have previously been free from the effects of exotic bees.

XX. Description of a new Genus of Exotic Bees

Transactions of the Royal Entomological Society of LondonVolume 2, Issue 2 p. 112-113 XX. Description of a new Genus of Exotic Bees J. O. Westwood F.L.S., J. O. Westwood F.L.S.Search for more papers by this author J. O. Westwood F.L.S., J. O. Westwood F.L.S.Search for more papers by this author First published: July 1838 https://doi.org/10.1111/j.1365-2311.1836.tb00305.xCitations: 2Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume2, Issue2July 1838Pages 112-113 RelatedInformation