Bee Flower Research Articles

Enhanced Life Time Improvement for Wireless Body Sensor Networks using Optimal Clustering and Advanced Path Selection Protocol

The medical enhancements have been improved to increase the life span of mankind. High penetration of Wireless Sensor Network in medical field helped the doctors to diagnose the patience in accurate manner and prescribe the medicines accordingly. In this modern Era, many people have permanent implant like face maker and it is life threatening to keep changing this body enhancement and it is need to have a system in place to increase the functionality of the Wireless Body Sensors. The important parameter which drags the battery energy and reduces its life span is path loss, and transmission loss. This paper proposes enhanced life time improvement for wireless body sensor networks using optimal clustering and advanced path selection protocol in short Energy Proficient Reliable Multi-hop Routing protocol. The EPMR designed in two stages, the first stage start with the collection of data from all body sensors is done through optimal clustering technique based Modified Conditional Spider Optimization (M-CSO) which avoids continuous individual transmission of data by the sensing nodes to base station in multi- hop distance (this stage the transmission loss is eliminated or reduced) hence the protocol concentrate to reduce transmission losses and the second stage implements the discovery of distance is done through by deploying Modified Flower Bee Algorithm (M-FBA), this stage the protocol finds best suitable and shortest next node to transmit the data. The finding of this paper is simulated using Math lab Simulink and verified through Network Simulator – 2 (NS-2) tools for validation and real time implementation of the results. The result obtained by this proposed method suggests that it has enhanced the sensor life term in many folds in comparisons with existing methodologies.

Screening and Bioguided Fractionation of Mimosa pigra L. Bee Pollen with Antioxidant and Anti-Tyrosinase Activities

Abstract Bee pollen, one of the economic bee products, is widely known as a nutritional food with many bioactivities that depend on many such factors as bee species, plant source and biogeography. For this study, bee pollen was collected from Apis mellifera, harvested from the flowers of mimosa (Mimosa pigra L.) in the Chiang Mai province, Thailand. The sample was extracted in methanol (MeOH) and then sequentially partitioned with hexane, dichloromethane (DCM) and MeOH in order to isolate compounds depending on their polarities. The obtained extracts were then tested for their antioxidant and anti-tyrosinase activities through 1,1-diphyenyl-2-picrylhydrazyl (DPPH) assay and for/through inhibition of mushroom tyrosinase extract, respectively. The DCM partitioned extract of mimosa flower bee pollen (DCMMBP) provided the highest antioxidant activity, with an effective concentration at 50% (EC50) of 192.1 μg/mL, and was further fractionated by silica gel 60 column chromatography and Sephadex LH20 size exclusion chromatography. All fractions were tested for their antioxidant activity and analyzed for the chemical structure through nuclear magnetic resonance (NMR). The most active fraction (EC50 of 121.3 μg/mL) was a mixture of compounds, but the isolated flavonoid, naringenin, had a negligible antioxidant activity. In contrast, all three partitioned extracts and pooled fractions after silica gel 60 column chromatography provided no anti-tyrosinase activity (IC50 of > 500 μg/mL) and a very low percentage of tyrosinase inhibition (0–2.99 ± 3.18%), compared to kojic acid (IC50 of 8.58 μg/mL and tyrosinase inhibition of 74.2 ± 1.25%).

Different effects of reward value and saliency during bumblebee visual search for multiple rewarding targets

Several animals, including bees, use visual search to distinguish targets of interest and ignore distractors. While bee flower choice is well studied, we know relatively little about how they choose between multiple rewarding flowers in complex floral environments. Two factors that could influence bee visual search for multiple flowers are the saliency (colour contrast against the background) and the reward value of flowers. We here investigated how these two different factors contribute to bee visual search. We trained bees to independently recognize two rewarding flower types that, in different experiments, differed in either saliency, reward value or both. We then measured their choices and attention to these flowers in the presence of distractors in a test without reinforcement. We found that bees preferred more salient or higher rewarding flowers and ignored distractors. When the high-reward flowers were less salient than the low-reward flowers, bees were nonetheless equally likely to choose high-reward flowers, for the reward and saliency values we used. Bees were also more likely to attend to these high-reward flowers, spending higher inspection times around them and exhibiting faster search times when choosing them. When flowers differed in reward, we also found an effect of the training order with low-reward targets being more likely to be chosen if they had been encountered during the more immediate training session prior to the test. Our results parallel recent findings from humans demonstrating that reward value can attract attention even when targets are less salient and irrelevant to the current task.

Linking bacterial diversity to floral identity in the bumble bee pollen basket

AbstractMultitrophic interactions are ubiquitous in nature and form the basis of biodiversity. For example, bumble bees visit flowers to collect pollen, on which a variety of bacteria exist. Such bacteria consist of pathogens and mutualists and therefore have consequences for bumble bee colony fitness. However, we still know little about how plant diversity and floral selection by bees translate into the bacterial diversity and composition on the pollen consumed by important pollinators. The aim of this study was to characterize the bacterial and floral alpha and beta diversity from bumble bee corbicula (pollen baskets), identify core communities, and characterize their functional role. We found that bacterial alpha diversity (i.e., the diversity of bacteria determined from the pollen basket of a single bumble bee) was positively correlated with floral pollen alpha diversity (i.e., the diversity of plants from that same pollen basket). Bacterial beta diversity (i.e., bacterial composition) was generally weakly correlated with pollen beta diversity (i.e., floral composition). The abundance of some bacterial genera and pollen families was correlated, specifically Lactobacillus and Acinetobacter were positively correlated with Asteraceae pollen and negatively correlated with Lamiaceae pollen. The most widespread bacteria (the “core OTU”) in bumble bee pollen baskets included both possibly beneficial (Lactobacillus) and potentially pathogenic (Pseudomonas) taxa, but more core OTU functions were unknown vs. known for bumble bees, illustrating the importance of understanding bee–flower–microbe relationships in natural settings.

Hand pollination and natural pollination by carpenter bees (Xylocopa spp.) in Passiflora edulis Sims. f. flavicarpa Deg. (yellow passion fruit)

We investigated the fruit set and quality of yellow passion fruit subjected to hand and natural pollination by carpenter bees (Xylocopa spp.) in the Philippines. We also recorded the foraging behavior of the bees. A quadrat measuring 6 m x 7 m was marked in a yellow passion fruit plantation for the investigation. Two groups of 20 flowers that had been either hand pollinated or visited by the bees were followed to determine fruit set and quality. The hand pollinated flowers had significantly greater fruit set (15/20 versus 7/20), fruit weight, transverse diameter, longitudinal diameter, peel weight, number of seeds, and juice yield. Flowers that were self-pollinated by hand produced no fruit. Bee flower visit times and patterns were also investigated. The carpenter bees started visiting the passion fruit flowers from 7:00 AM to 5:00 PM, with peak visitation at 1:00 PM. The greatest mean duration of flower visits was observed at 11:00 AM (304 s), which coincided with the observed peak hour of flower opening. We observed random distances in the flight patterns of the carpenter bees, which was independent of flower distances (Kolmogorov-Smirnov test; µ=3.34 < σ2=7.91 vs. µ=2.40 > σ2=1.20). We conclude that passion fruit farmers can utilize supplemental hand pollination to increase yield when the main pollinators such as Xylocopa spp. are not available in sufficient numbers.

Environmental Display Can Buffer the Effect of Pesticides on Solitary Bees.

Environmental quality (e.g., diversity of resource availability, nesting sites, environmental display) plays an important role in an animal’s life. While homogeneous environments can restrict organisms from developing activities such as food seeking (behavioral impairment), more complex environments allow animals to perform activities with learning and behavioral perfecting outcomes. Pesticides are known to affect the learning and foraging behaviors of bees; however, little is known about the counterbalance displayed by the environment. Herein, we conducted two experiments that simulated distinct environmental displays, in which the effects of a fungicide (IndarTM 5EW-febunconazole) on solitary bee foraging activities were tested. We found that the fungicide only impaired the activities of bees in one of the studied environments. The difference in visitation rates and flower exploitation of bees between the two different environmental displays led to changes in metrics of bee–flower networks across environments. Linkage density, a metric associated with pollination efficiency that is known to be impacted by different environments, differed across environments. Our results showed that ecological interaction network metrics can differ regarding the different environmental displays. This study indicates that environmental complexity helps balance the negative effects of pesticides on solitary bees and highlights the potential use of solitary bees as model organisms for experimental simulations of environmental change.

Australian native flower colours: Does nectar reward drive bee pollinator flower preferences?

Colour is an important signal that flowering plants use to attract insect pollinators like bees. Previous research in Germany has shown that nectar volume is higher for flower colours that are innately preferred by European bees, suggesting an important link between colour signals, bee preferences and floral rewards. In Australia, flower colour signals have evolved in parallel to the Northern hemisphere to enable easy discrimination and detection by the phylogenetically ancient trichromatic visual system of bees, and native Australian bees also possess similar innate colour preferences to European bees. We measured 59 spectral signatures from flowers present at two preserved native habitats in South Eastern Australia and tested whether there were any significant differences in the frequency of flowers presenting higher nectar rewards depending upon the colour category of the flower signals, as perceived by bees. We also tested if there was a significant correlation between chromatic contrast and the frequency of flowers presenting higher nectar rewards. For the entire sample, and for subsets excluding species in the Asteraceae and Orchidaceae, we found no significant difference among colour categories in the frequency of high nectar reward. This suggests that whilst such relationships between flower colour signals and nectar volume rewards have been observed at a field site in Germany, the effect is likely to be specific at a community level rather than a broad general principle that has resulted in the common signalling of bee flower colours around the world.

To bee or not to bee: The ‘raison d'être’ of toxic secondary compounds in the pollen of Boraginaceae

Abstract While the presence of secondary compounds in floral nectar has received considerable attention, much less is known about the ecological significance and evolutionary origin of secondary ‘toxic’ compounds in pollen. It is unclear whether the presence of these compounds in pollen is non‐adaptive and due to physiological ‘spillover’ from other floral tissues, or whether these compounds serve an adaptive function related to plant–pollinator interactions, such as protection of pollen against pollen thieves. Combining an experimental approach with phylogenetic comparative methods, and using western Palaearctic Boraginaceae as a model system, we investigate how pollen secondary metabolites influence, and are influenced by, relationships with bees, the main functional group of pollen‐foraging pollinators. We found a significant relationship between the levels of secondary compounds in the corollas and those in the pollen in the investigated species of Boraginaceae, suggesting that baseline levels of pollen secondary compounds may partly be due to spillover from floral tissues. At realistic levels, pollen secondary compounds showed significant detrimental effects on bee pre‐imaginal development, in agreement with previous egg‐transfer experiments showing that in some cases Boraginaceae pollen did not support pre‐imaginal development in bees not specialized on these plants. We also show that phylogenetically independent Boraginaceae taxa rewarding pollinators with pollen in addition to nectar exhibit significantly lower levels of toxic compounds in the pollen than taxa where the main reward is postulated to be nectar. Lastly, in contrast to our predictions, there was no positive association between toxin levels in the pollen of a given plant taxon and the number of bee species specialized on this taxon. We integrate all these findings and formulate an evolutionary scenario to account for the presence of toxic compounds in the pollen of Boraginaceae. We suggest that baseline levels of toxic compounds may be found in pollen due to spillover from other floral tissues and not primarily because of bee–flower interactions. Since pollen toxins can have detrimental effects on bees, we propose that selection acts to lower pollen toxin levels in plants where pollen, in addition to nectar, serves as a reward to bees. A free Plain Language Summary can be found within the Supporting Information of this article.

Experimental field test of the influence of generalist stingless bees (Meliponini) on the topology of a bee–flower mutualistic network in the tropics

1. Generalists are assumed to play a key role in structuring and stabilising animal–plant mutualistic networks. Until now, analyses on the effects of generalists have been based on empirical field data or simulations. The present natural field experiment manipulated the abundance of a generalist and abundant stingless bee [Melipona (Eomelipona) marginata] to determine the effects on the mutualistic network.2. Networks were generated, and associated metrics were used for comparing replicate plots with and without the insertion of stingless bee nests.3. Unweighted metrics and the basic qualitative structural pattern of networks (high nestedness, very low modularity and specialisation) was not affected by experimental variation in stingless bee abundance because they exert strong basal effects on the plant–pollinator community under natural conditions of abundance. Still, increased abundance caused significant variation in weighted nestedness and modularity and community‐level specialisation.4. Supporting predictions of neutral models, increased abundance of the stingless bee led to an increase in most of its specific metrics, expressing the expansion of its realised trophic niche.5. During this process, specialist and other generalist bees were affected in different ways. More plant species became even more dependent on this stingless bee (increased asymmetry).6. Long‐term effects could not be inferred directly from instantaneous values of network metrics. Nonetheless, the increased abundance of the generalist stingless bee may both reduce the local level of ecological specialisation in the short term and affect the spatial distribution of less abundant and/or specialist bee species and plants in the long term.

Urban bumble bees are unaffected by the proportion of intensely developed land within urban environments of the industrial Midwestern USA

Urban environments have become an unexpected and promising avenue for pollinator conservation. One group of pollinators, bumble bees, might be especially well suited to utilize the heterogeneous landscape of urban ecosystems. Weedy margins (pervious land adjacent to impervious surfaces such as roads and paved lots) offer plentiful flowers for bees, but are often overlooked in urban pollinator studies. If weedy margins buffer urban bees from loss and fragmentation of foraging habitat in cities, then urban development may not have as strong of a negative effect on bumble bees as previously thought. In this study we test the hypothesis that bumble bee abundance and species richness in these weedy margins will not be affected by the degree of urbanization. We surveyed bees and flowers within weedy plots of land in six industrial cities of the Midwestern USA. Bumble bee abundance and richness were not influenced by the proportion of intensely developed land in the surrounding landscape, but abundance increased with local floral abundance. Bumble bees were also significantly more abundant than other bee groups (honeybees and ‘other’ wild bees). We found that weedy margins and weedy plant species provide important resources to urban pollinators, and to bumble bees in particular. If small patches of habitat can sustain bees in the city, future efforts of urban pollinator conservation could focus on the installation of high-quality micro-meadows, increasing the availability of quality habitat for pollinators.

Effects of grazing intensity, habitat area and connectivity on snail-shell nesting bees

The effects of habitat loss and fragmentation on wild bee populations are still not fully understood. Availability of resources, parasitism and habitat connectivity might influence population sizes of bees. Whereas floral resources for wild bees have been considered in research and conservation, nesting resources have been largely neglected as these are challenging to investigate. Snail shells are the exclusive nesting cavities for several Osmia species and provide a good - but so far unused - tool to study factors driving bee population dynamics. We investigated the effects of habitat area, connectivity and management of semi-natural grasslands on populations of snail-shell nesting bees. On 23 calcareous grasslands, we monitored snail shell colonization by providing empty snail shells as nesting resources, and recorded flower-visitor interactions.Five snail-shell nesting Osmia species were found on the grasslands, which made almost a quarter of recorded bee flower visits. Three species colonized the offered snail shells with high variation between study sites, Osmia species, and snail shell size. Habitat area had a positive effect on the population size of the habitat specialist Osmia aurulenta, whereas the more generalist species Osmia bicolor was positively influenced by habitat connectivity. Destruction rates of snail shells increased with sheep grazing intensity, leading to an estimated loss of more than a third of all bee nests. We conclude that large and connected habitats benefit bee populations in fragmented landscapes, while conservation management regimes should take into account potential negative effects of grazing on specific nesting resources of specialized bee species.

Attracting Native Bees to Your Florida Landscape

Florida is home to approximately 315 species of native wild bees. These bees rely on flowers for survival; their diets consist exclusively of pollen and nectar harvested from flowers. Recently reported declines in some bee species have heightened awareness of bee conservation across the United States and motivated efforts to increase floral resources for bees. This 7-page fact sheet written by Rachel E. Mallinger, Wayne Hobbs, Anne Yasalonis, and Gary Knox and published by the UF/IFAS Entomology and Nematology Department shows how gardeners and land managers can aid in conservation efforts by planting flowers for bees in home or community gardens. http://edis.ifas.ufl.edu/IN1255

Overhead sprinkler irrigation affects pollinators and pollination in pumpkin (Cucurbita maxima)

Cucurbits are monoecious plants and most of them depend on pollinators for fruit set. However, studies suggest that pumpkin and squash fields are pollination deficient. Pollinator limitation, suboptimal flower sex ratio, and exploitative competition between invasive ants and bees are a few major suggested reasons for this. Pumpkin flowers have a corolla cup and secrete nectar throughout anthesis, which make them attractive to bees. In south India, honey bee (Apis cerana) is the major pollinator of pumpkin flowers. Like pollinators, water is also a limiting factor for growth and production of flowers in pumpkin. It has been suggested to use overhead sprinklers to irrigate and fertilize pumpkin fields. We hypothesized that the sprinkler affects the visitation characteristics of foraging bees in flowers and pollination, and so, we performed an experiment to test this. For this reason, we recorded pollinator visits on staminate and pistillate flowers for 15 min and poured water in the flower cups and examined the water retention time and the visitation characteristics of pollinators in both staminate and pistillate flowers, and fruit set in pistillate flowers. Water remained inside the staminate and pistillate flower cups until the flower senescence. Honey bees entered and foraged nectar/pollen in flowers during the waterless condition. In water-filled flowers, honey bees hovered around or landed only on the corolla and did not forage floral resources or contact the reproductive parts. As a consequence, none of the water-filled flowers developed fruits. Therefore, the overhead sprinkler irrigation, despite cover a large area effectively, may not be an appropriate irrigation method for pumpkin during flowering period.

Dryland Organic Farming Partially Offsets Negative Effects of Highly Simplified Agricultural Landscapes on Forbs, Bees, and Bee-Flower Networks.

Industrialized farming practices result in simplified agricultural landscapes, reduced biodiversity, and degraded species-interaction networks. Thus far, most research assessing the combined effects of farming systems and landscape complexity on beneficial insects has been conducted in relatively diversified and mesic systems and may not represent the large-scale, monoculture-based dryland agriculture that dominates many regions worldwide. Specifically, the effects of farming systems on forbs, bees, and their interactions are poorly understood in highly simplified dryland landscapes such as those in the Northern Great Plains, United States, an area globally important for conventional and organic small grain, pulse, forage, and oilseed production. During a 3-yr (2013-2015) study, we assessed 1) the effects of dryland no-till conventional and tilled organic farming on forbs, bees, and bee-flower networks and 2) the relationship between natural habitat and bee abundance. Flower density and richness were greater in tilled organic fields than in no-till conventional fields, and forb community composition differed between farming systems. We observed high bee diversity (109 taxa) in this highly simplified landscape, and bee abundance, richness, and community composition were similar between systems. Compared with tilled organic fields, bee-flower interactions in no-till conventional fields were poorly connected, suggesting these systems maintain relatively impoverished plant-pollinator networks. Natural habitat (11% of the landscape) did not affect small-bodied bee abundance in either farming system but positively affected large-bodied bees within 2,000 m of crop-field centers. In highly simplified agricultural landscapes, dryland organic farming and no-till conventional farming together support relatively high bee diversity, presumably because dryland organic farming enhances floral resources and bee-flower networks, and no-till management in conventional farming provides undisturbed ground-nesting habitats for wild bees (Hymenoptera: Apoidea).

Impact of inundation regime on wild bee assemblages and associated bee–flower networks

Wild bee assemblages on flood-prone meadows were compared with those on rarely inundated sites along the river Danube in easternmost Lower Austria. We sampled flower-visiting bees on 32 meadows from April to August 2016. Although we recorded more bee individuals on rarely inundated meadows, total bee species richness was higher on regularly flooded meadows and we observed a stronger differentiation diversity of bees among annually flooded meadows. Three network metrics derived from a bipartite plant–bee interaction matrix were unaffected by flooding regime. We conclude that extreme floods, which sporadically affect the investigated habitats, may have a devastating effect on wild bee populations, but communities quickly recover. This resilience surely depends on recolonization from the surrounding landscape, which emphasizes the need to consider community dynamics in highly variable floodplain areas not only locally, but on a landscape scale.

Low endemic bee diversity and very wide host range in lowland Fiji: support for the pollinator super-generalist hypothesis in island biogeography

The success of invading plants in island ecosystems has often been inferred to result from ‘invader complexes’, where cointroduced plants and their specialist pollinators can reciprocally enhance each other’s spread. However, it has also been suggested that in islands with low pollinator diversity, those pollinators should evolve into super-generalists that may be able to pollinate a wide range of exotic plants, enabling the spread of exotic weeds. Fiji has a very depauperate endemic bee fauna and previous studies have suggested that its only lowland bee species, Homalictus fijiensis (Apoidea: Halictidae), has a very wide range of host plants. However, those studies only included a small number of endemic flowering plants. Our study expands observations of bee–flower interactions to explore host plant ranges of H. fijiensis and introduced bee species to include a wider variety of native and introduced plant species. We show that H. fijiensis does have a wider host range than introduced bees, including Apis mellifera (Apoidea: Apidae), and an ability to exploit extrafloral nectaries and poricidal anthers that are not utilised by the introduced bee species. Our results support the hypothesis that super-generalism can evolve in islands where pollinator diversity is low, and that this may make those islands susceptible to weed invasions.

BACTERIAL CONTAMINATION OF VACUUM STORED FLOWER BEE POLLEN

Water content, water activity (Аw) and mean microbiological characteristics were determined in fresh and dried flower bee pollen collected from apiary from North east region in Bulgaria. Higher microbial counts were established for fresh than for dried bee pollen after long-time (1 and 2-years) vacuum-packed cold storage (0-4 ºС and - 18 ºС). It was found contamination with Pantoea spp., Prot. mirabilis, Citrob. freundii, Serratia fonticola, Raoultella planticola/ornithinolytica, S. hominis (subspecies hominis), S. sciuri (subspecies sciuri), Flavimonas orizihabitans, Achromobacter denitrificans, Arthrobacter globiformis, Psychrobacter phenylpyruvicus, B. pumilis and Enterococcus faecalis in the dried flower bee pollen intended for human consumption. Fresh bee pollen that is an intermediate product not intended for human consumption besides these contained Prot.vulgaris, E.coli, Staph. epidermidis and B. subtilis.

Isolation and Identification of Bacteria in Flower Bee Pollen

The main food safety requirements include accurately formulated criteria for the presence of specific microorganisms. The inconsistent literature data about the microbial species diversity in bee pollen during its collection, processing, and storage necessitate integral microbiological examinations. The purpose of this research work was to prove the algorithm for isolation and species level differentiation of bacteria from the Enterobacteriaceae, Pseudomonadaceae, Staphylococcaceae, Bacillaceae, and Micrococcaceae families on fresh and dried flower bee pollen from Bulgaria.

Ultrathin g-C3N4 nanosheets coupled with carbon nanodots as 2D/0D composites for efficient photocatalytic H2 evolution

Carbon nanodots synthesized from rapeseed flower bee pollens were used to couple with ultrathin g-C3N4 nanosheets for preparing the 2D/0D type photocatalysts by a hydrothermal method. The g-C3N4 nanosheets (UCN) obtained from ammonium chloride blowing dicyandiamide methods exhibit ultrathin two-dimension structure with a series of hollow spherical structures, and CQDs are well dispersed and uniformly anchored into the UCN network via π-π stacking interactions. The incorporation of CQDs can effectively expand visible light absorption regions via photosensitization and suppress the recombination of photo-induced carriers. Time-resolved fluorescence spectroscopy, electron paramagnetic resonance technology and photoelectrochemical measurements together reveal that CQDs serve as electron transfer mediation to facilitate charge separation and extend the lifetime of photo-induced carriers. The UCN/CQDs-0.2% composite has the optimal H2 evolution of 88.1μmol/h, 9.79, 3.02 and 1.91 folds of bulk g-C3N4 (BCN), pristine UCN and BCN/CQDs-0.2%, respectively. Consequently, the UCN/CQDs composites exhibit high photocatalytic activity of hydrogen release under the visible light irradiation.

More than protein? Bee–flower interactions and effects of disturbance regimes revealed by rare pollen in bee nests

Bees and their host flower populations were studied by identifying pollen to species or genus, from trap nests where bees were reared. Rare plant species in bee diets, and disturbance regimes, have not previously been researched and are emphasized here. Two focal bee groups with one species each (Megachilidae and Apidae) were studied in a 500,000-ha tropical reserve in the Yucatan Peninsula nine complete years. The number of rare or major pollen species in nests had no statistical correlation; thus, rare pollen analysis complements study of major brood provisions. We found most nests (87 % Megachile zaptlana, 93 % Centris analis) contained rare pollen; only 12 % of the 438 nests contained major pollen alone. Rare pollen sometimes indicated an energy source rather than a scarce protein resource. Trichome nectar of Cydista, along with Ipomoea and Caesalpinia, were nectar sources. Malpighiaceae, despite lacking nectar, often provided the complete Centris diet. Considering rare pollen, only Centris responded to drought, or competition from immigrant honeybees. Neither bee responded to hurricanes. Drought years coincided with low bee populations; Centris nests contained more rare species then. After feral Africanized honeybees colonized, Centris had more major species and fewer rare. Some herbarium vouchers from the study area contained exotic pollen, demonstrating in situ floral contamination and ecological generalization by bees, but this rarely occurred in plants found among the bee diets. Megachile and Centris responded differently to competition and resource scarcity, and plausibly evolved under different disturbance regimes, yet appeared well adapted to hurricane disturbance.