Meliponula Ferruginea Research Articles

Differences in the biochemical content and radical scavenging activity of propolis from different parts of a Meliponula ferruginea hive.

Research on stingless bee products has increased in recent years, and of particular interest is propolis because of its biological activities such as antioxidant and antimicrobial. However, there is paucity of information regarding intra-hive variations in the biochemical composition and biofunctional properties of this propolis. In this study, we investigated the phytochemicals and radical scavenging activity (RSA) of Meliponula ferruginea propolis from 10 wooden hives (n = 49). The samples were collected from five different locations comprising the entrance, involucrum, pillars, pots and sealant. Principal component analysis showed that there is an intra-hive variation in phytochemical content and RSA. Phenolic content constituted the highest phytochemical content in all the locations. The sealant and entrance had the highest amounts of phytochemicals compared to the involucrum, pillars and pots. Further analysis of propolis extracts by gas chromatography-mass spectrometry revealed occurrence of different compounds such as monoterpenoids, hydrocarbons, triterpenoids and alkaloids. Hydrocarbons were common in all parts while monoterpenes and triterpenes were present in the entrance. The findings of our study indicates that there is an intra-hive variation in propolis of M. ferruginea and hence this information will provide further insight into better understanding of stingless bee propolis.

Discrimination of honeys produced by Tanzanian stingless bees (Hymenoptera, Apidae, Meliponini) based on physicochemical properties and sugar profiles

Honey composition vary according to floral origin and bee species from which it is produced. Understanding the composition of honey is essential for guaranteeing its quality and authenticity, and revealing its potential benefits. Studies on honeys produced by Afrotropical stingless bees are scarce resulting into limited understanding and underutilization. The current study investigated the physicochemical properties and sugar profiles of honeys produced by six stingless bee species (Dactylurina schmidti, Hypotrigona gribodoi, Meliponula beccarii, Meliponula ferruginea, Meliponula togoensis and Plebeina armata) from different vegetation zones of Tanzania. Permutation analysis of variance (PERMANOVA) and Kruskal-Wallis tests were conducted to assess how bee species and vegetation influenced the studied parameters. Furthermore, we employed principal component analysis (PCA) and linear discriminant analysis (LDA) to discriminate honey samples according to bee species and vegetation zones. Our findings show that honey composition was greatly influenced by the identity of bee species which affected 84.6 % of the studied parameters, compared to vegetation zones which affected only 23.1 % of the studied parameters. Stingless bee honey showed significant variation from the international quality standards established for Apis mellifera honey. Also, the levels of free acidity (32.05–99.95 meq/Kg), ash content (0.09–0.81 % w/w) and reducing sugars (43.79–50.82 g/100 g) in some honey samples deviated from the East African Community standards for stingless bee honey. PCA and LDA revealed that the physicochemical properties and sugar profiles can be used to classify stingless bee honeys according to their bee species origin. We recommend further studies to elucidate essential markers that can be used in identifying the entomological source of stingless bee honey.

Determination of total flavonoids, phenolics, and antioxidant activity of propolis from six stingless bee species in Kenya

AbstractBackgroundPropolis is one of the hive products made by bees from wax and plant resins, which makes it rich in phytochemicals such as flavonoids and phenolic. The chemical composition of propolis from stingless bees is affected by several factors including vegetation type and species. In Kenya, we have diverse landscape vegetation and over 12 stingless bee species. Lifestyle diseases are affecting more people due to unhealthy diets and exposure to harmful chemicals, which lead to oxidation in cells. This led to the production of super radicals, which cannot be neutralized only by the endogenous antioxidants in the body. This has led to increased demand for exogenous antioxidants obtained from the diet. Propolis is a known source of natural antioxidants too due to the presence of polyphenols.ResultsIn our study, we determined the total content of flavonoids, phenolic, and the antioxidant activity of propolis from six stingless bee species from Kenya. The total flavonoid content (TFC) in all species ranged from 651.90 to 3262.26 mg QE/100 g, while the total phenolic content (TPC) ranged from 586.36 to 2010.53 mg GAE/100 g. Among the species, Meliponula beccarii had the highest concentration of total flavonoids, Meliponula togoensis had high concentrations of total phenolic, while Meliponula ferruginea had the highest antioxidant activity.ConclusionThe outcome of this study demonstrates that propolis from Kenyan stingless bees have varying amounts of phytochemicals, which is dependent on the species identity. Hence it is a good source of exogenous natural antioxidants.

A fungal-based pesticide does not harm pollination service provided by the African stingless bee Meliponula ferruginea on cucumber (Cucumis sativus)

Stingless bees (Apidae: Meliponini) provide pollination services to crops and produce high–quality honey. The application of agrochemicals during the management of crop pests is an increasing threat to pollinators and the ecosystem services they provide. Biopesticides are considered as better alternatives; however, there is limited evidence of their impact on stingless bees. We evaluated the effect of the most widely used African fungal biopesticide (Metarhizium anisopliae ICIPE 69) on mortality, foraging behavior and pollination success of the African stingless bee Meliponula ferruginea under semi-field conditions. Colonies of M. ferruginea were introduced into four 24 m2 greenhouse compartments containing blooming cucumber (Cucumis sativus) plants. Cucumber plants were sprayed with a suspension of the biopesticide alongside a sterile 0.05% Triton–100–X (control). The experiment was repeated three times during different cucumber growing seasons. Biopesticide application did not significantly affect M. ferruginea mortality, flight activity, flower visitation, pollen foraging, C. sativus fruit set or C. sativus yield. Forager bees acquired a high number of conidia (7,600 ± 54 conidia /bee) immediately after biopesticide application; however, a significant decline was observed in the subsequent days. Conidial persistence and viability on plant surfaces declined significantly with days. There was no correlation between conidial acquisition and pollen load by forager bees (657 ± 29 pollen/bee). This study demonstrates that M. anisopliae ICIPE 69 did not negatively impact M. ferruginea mortality, pollination behaviour and success, and can therefore be safely used in stingless bee–dependent crop systems.

Effective pollination of greenhouse Galia musk melon (Cucumis melo L. var. reticulatus ser.) by afrotropical stingless bee species

An increasing demand for pollination services highlights the need for research on alternative pollinators for greenhouse and open field food crops. We compared the foraging behaviour and effectiveness of seven endemic African Meliponinae (Meliponula bocandei, Dactylurina schmidti, Plebeina hildebrandti, Meliponula lendliana, Hypotrigona gribodoi, Meliponula ferruginea, Meliponula togoensis) as alternative pollinators to honey bees of greenhouse cultivated Cantaloupe melons. It was observed that honey bees started foraging sooner after introduction in the greenhouse (av. 4 days) than the stingless bee species (8 to 16 days). Stingless bees were mainly harvesting nectar (ca. 2/3 of all flower visits) and M. ferruginea, M. togoensis, H. gribodoi and P. hildebrandti spent more time collecting nectar than other stingless bee species. Fruit maturation was significantly faster when flowers were pollinated by stingless bees compared to honey bees, with the shortest fruit maturation time found when flowers were pollinated by M. bocandei and H. gribodoi. All treatments resulted in fruits of similar roundness and ellipsoid ratios. The highest fruit weight and fruit volume were obtained from flowers pollinated by either manual pollination, H. gribodoi, M. bocandei, M. lendliana and P. hildebrandti compared to honey bees. Correspondingly, pollination by the latter 5 species resulted in the highest seed counts per fruit, although these differences did not affect seed weight or volume. Altogether, our results indicate that stingless bees such as H. gribodoi, M. bocandei, M. lendliana and P. hildebrandti are more efficient pollinators of sweet melon than A. m. scutellata and can be recommended for use in greenhouse crops.

African endemic stingless bees as an efficient alternative pollinator to honey bees in greenhouse cucumber (Cucumis sativus L)

The current honey bee decline necessitates the use of alternative native pollinators to ensure global food security. Here, we compared the pollination behaviour and efficiency of the African honey bee (Apis mellifera) and six African endemic Meliponini (Meliponula bocandei, Dactylurina schmidti, Meliponula lendliana, Hypotrigona gribodoi, Meliponula ferruginea and Meliponula togoensis) in a greenhouse with the non-parthenocarpic cucumber variety Super Marketer. Honey bees and D. schmidti started foraging on introduction in the greenhouse, while M. lendliana and M. togoensis showed the longest delay. In most species, foragers collected nectar and pollen, excepting M. bocandei that specialized in nectar collection, and H. gribodoi and M. togoensis, specialized in pollen collection. African honey bees visited flowers the shortest, while H. gribodoi and D. schmidti had a 2-fold probing time, on average. Most stingless bees species had a lower hive activity with fewer foragers encountered per hour than for honey bees, except D. schmidti. M. bocandei, M. ferruginea, A. mellifera scutellata and H. gribodoi, yielded a seed germination percentage of around 90%. M. lendliana, M. togoensis and D. schmidti yielded a much lower seed germination percentage around 30%, which indicates that the quality of pollination was remarkably lower by using these three species. The highest sugar content was recorded in fruits from flowers pollinated by M. bocandei, African honey bees, D. schimdti or M. togoensis with the same solid content as the gold standard method, i.e., hand cross-pollination. We found that M. bocandei was the most efficient cucumber pollinator of all species tested: because pollination by this species yielded the largest and heaviest fruits and the highest seed numbers.

Susceptibility of the Western Honey Bee Apis mellifera and the African Stingless Bee Meliponula ferruginea (Hymenoptera: Apidae) to the Entomopathogenic Fungi Metarhizium anisopliae and Beauveria bassiana.

This study assessed the nontarget effect of entomopathogenic fungi on the Western honey bee Apis mellifera L. and the African stingless bee Meliponula ferruginea Cockrell (Hymenoptera: Apidae). Pathogenicity of five Metarhizium anisopliae (ICIPE 7, ICIPE 20, ICIPE 62, ICIPE 69, and ICIPE 78) (Metschnikoff) Sorokin (Hypocreales: Clavicipitaceae) and one of Beauveria bassiana (ICIPE 284) (Balsamo) Vuillemin (Hypocreales: Cordicipitaceae) isolates were evaluated on bees at 108 conidia/ml. Conidial acquisition was evaluated immediately after exposure. Apis mellifera acquired more conidia (2.8 × 104–1.3 × 105 conidia per bee) compared to M. ferruginea (1.1 × 104–2.3 × 104 conidia per bee). In the bioassay with A. mellifera, ICIPE 7, ICIPE 20, and ICIPE 69 moderately reduced the survival by 16.9, 17.4, 15.3%, with lethal times LT10 = 7.4, 7.6, 8.1 d and LT25 = 8.7, 10.0, 9.9 d, respectively. The three isolates caused A. mellifera mycosis of 11.6–18.5%. None of the isolates had a significant effect on M. ferruginea. The tested isolates are nontoxic to bees according to the International Organization of Biological Control (IOBC) classification. However, the effect of ICIPE 7, ICIPE 20, and ICIPE 69 merits further studies on bee colonies, especially those of A. mellifera, under field conditions.

A Preliminary Study of Chemical Profiles of Honey, Cerumen, and Propolis of the African Stingless Bee Meliponula ferruginea.

Recently, the honey and propolis of stingless bees have been attracting growing attention because of their health-promoting properties. However, studies on these products of African Meliponini are still very scarce. In this preliminary study, we analyzed the chemical composition of honey, two cerumen, and two resin deposits (propolis) samples of Meliponula ferruginea from Tanzania. The honey of M. ferruginea was profiled by NMR and indicated different long-term stability from Apis mellifera European (Bulgarian) honey. It differed significantly in sugar and organic acids content and had a very high amount of the disaccharide trehalulose, known for its bioactivities. We suggested trehalulose to be a potential marker for African stingless bee honey analogously to the recent proposal for Meliponini honey from Asia, South America, and Australia and demonstrated its easy discrimination by 13C NMR. Propolis and cerumen were studied by GC-MS (gas chromatography-mass spectometry). The samples contained mainly terpenoids (di-and triterpenes) but demonstrated qualitative and quantitative differences. This fact was an indication that possibly M. ferruginea has no strict preferences for resins used to construct and protect their nests. The antimicrobial and anti-quorum sensing properties of the two materials were also tested. These first results demonstrated that the honey, cerumen, and propolis of African stingless bees were rich in biologically active substances and deserved further research.

Stingless Beekeeping in Uganda: An Industry in Its Infancy

Stingless bees are important resources for pollination of crops, production of medicinal honey and other products. However, throughout the developing countries in Africa, meliponiculture has received less attention in beekeeping development programmes. Here, the current situation of stingless beekeeping in Uganda is assessed. First, stingless bee species utilised for their products were collected and identified. Thereafter, the economic benefits derived from stingless beekeeping in the Western Highlands agro-ecological zones of Uganda with anecdotal reports of meliponiculture were analysed. The findings reveal that stingless beekeeping is in its early stages of development in Uganda. Four stingless bee species were identified: Meliponula bocandei, Meliponula nebulata, Meliponula ferruginea and Plebeina hildebrandtii that are currently used for honey and propolis. These stingless bee species can be selected for domestication, targeting different products such as honey, propolis and pollen to make meliponiculture more profitable. Indigenous knowledge of beekeepers that can assist in locating wild stingless bee nests for domestication was documented as it is essential for the preservation of this practice. In order to transform the stingless beekeeping industry in Uganda, training needs such as hive making, colony management, product harvesting and processing will have to be addressed.

Implications of fragile landscapes for endemic pollinators in an eastern afro-montane biodiversity hotspot of Kenya

This study was carried out to determine how disturbances could shape the natural occurrence of African meliponine bee species in different ecological habitats of Taita hills of Kenya and how this could lead to changes in their diversity. Habitats sampled were indigenous forests, exotic forests, mixed highland forests, Acacia dominated bush lands, mixed deciduous woodlands and grasslands which were further categorized as either fragmented or un-fragmented habitats based on levels of disturbance. The study sites were chosen based on various features such as, forest fragment size, level of forest fragment isolation, forest fragment age, and level of degradation. In all study locations, meliponine bee species were sampled using the conventional complementary method, belt transect (direct observation of nesting colonies synonymous to a visual census) from the months of March to September 2014 (combining both the long rainy season and dry season). Nesting colonies of the 4 meliponine bee species, namely, Hypotrigona gribodoi, Meliponula ferruginea (black), Hypotrigona ruspolii and Plebeina hildebrandti, were surveyed following a successive gradient. In each study site (25 ha), 20 linear transects of 250 m × 20 m each were established using a global positioning system (GPS) receiver to mark coordinates with relation to habitat type. Data such as nesting site/substrate, GPS coordinates of nest, and names of nesting trees were recorded. A total of four species depicted by the Renyi diversity profile was recorded in five out of the six main habitat types surveyed and a further extrapolation with Shannon index (EH) also predicted the highest species richness of 4.24 in a deciduous habitat type with more trees and vegetation and the lowest species of 1.01 in isolated forest patches habitat type. These meliponine bee species (Hypotrigona gribodoi, Hypotrigona ruspolii, Meliponula ferruginea (black) and Plebeina hildebrandti) were observed to be unevenly distributed across all six sampled habitats, further indicating that mixed deciduous habitat proved to be more diverse than Acacia dominated bush lands, grasslands and exotic forest strips which have all undergone varying levels of fragmentation. This has revealed that unprecedented conversions of natural habitats leading to fragmentations of such habitats is a key driving factor causing increased habitat isolation and vulnerability in this afro-montane region which may potentially distort local assemblages of native pollinators such as meliponine bee species.
 Keywords: Meliponine bees, habitat fragmentation, diversity, Eastern Afro Montane

Proximate, Physicochemical and Antimicrobial Analysis of Honey Produced by Apis mellifera and Meliponula ferruginea

Proximate, Physicochemical and Antimicrobial Analysis of Honey Produced by Apis mellifera and Meliponula ferruginea

Patterns of Diversity and Distribution of Arboreal Social Bees’ Beehives within Chimpanzees’ Home Range in a Forest-Savanna Mosaic (Comoé National Park, Côte d’Ivoire)

The goal of this study was to explain the patterns of diversity and distribution of arboreal social bees nesting in forest habitats of the Comoé National park, within the home-ranges of wild chimpanzees that consume their honey. Investigations were done using a total sixteen plots, one hectare each, established in three habitat types (mature forest island, secondary forest island and gallery forest). The diversity and distribution of arboreal social bees was estimated with visuals searches. The exploitation of the beehives of these bee by the chimpanzees was also evaluated using chimpanzees’ honey dipping tools as indicators. Results revealed five bees’ species belonging to two tribes; Meliponini (Meliponula ferruginea, Meliponula togoensis, Meliponula bocandei, Hypotrigona gribodoi) and Apini (Apis mellifera). Frequent exploitation of the honey of stingless bees by the chimpanzees was observed, except for H. gribodoi. Meliponula ferruginea was the most exploited species by chimpanzees. A total of 114 beehives were found in the overall established plots leading to an estimated density of 2.4 beehives/ha in the study area. Among the surveyed habitats, mature forest island was found to harbor the highest beehive density (4.2 beehives/ha), followed respectively by secondary-forest island (1.9 beehives/ha) and gallery forest (1.1 beehives/ha). Finally, all bee species were found nesting in cavities of trees with a DBH ranging from 15 to 87.3 cm, with a special preference for Dialium guinneense. However, the DBH of nesting trees and beehives’ height, measured from the ground level, did not significantly influence the honey exploitation by chimpanzees. In sum bee species diversity and distribution might be important in the survival of chimpanzees of a forest savanna landscape.

Nest architecture and colony characteristics of Meliponula (Axestotrigona) ferruginea (Hymenoptera, Apidae, Meliponini) in Cameroon

Stingless bees have evolved adaptive nest constructions strategies which have resulted in sophisticated nest architecture in many species while others lack certain structural components. However, no information exists on the nest biology and ecology on the genus Meliponula in Cameroon. This study aims to contribute to knowledge on the nest architecture and colony characteristics of Meliponula (Axestotrigona) ferruginea. Meliponula ferruginea belongs to the genus Meliponula and subgenus Axestotrigona. This species was first described by Le Peletier De Saini-Farrgeau (1836) and Michener (The bees of the world, The Johns Hopkins University Press, Baltimore and London, 2000) recently. In Cameroon the species has been collected in the northern parts of the country, but there has been no attempt to describe the nest architecture. Our stingless bee survey from the Bamenda highlands afromontane forests of Cameroon reveals that this species can either nest in tree trunks or in abandoned traditional hollow hives. Interestingly, 50% of colonies studied nested in traditional hollow hives originally baited for honeybees (Apis mellifera adansonii). The nest entrance of Meliponula (Axestotrigona) ferruginea ranged from 1 to 1.5 cm (1.2±0.0.24 cm) in diameter, while the external entrance tube extended up to 1.6+/-0.0.4 cm and the nest entrance tube can go up to 5 cm inward in depending on the thickness of the tree trunk. The nest is made up of sticky brown 5-7 (6+/-0.98) involucra sheets. The size of brood area depends on the age and condition of the nest. The length of the nest could be between 5.5 and 7.6 cm (6.8+/-0.98 cm) and up to 13+/- 4.16 cm combs with a comb diameter of about 7.5+/-1.29 cm. The cells and storage pots are oval in shape but the storage pots are much larger, about 3 times the size of cell. Generally, this study shows a lot of similarities with other previously studied species in terms of the nest characteristics and measurements. However, the above characteristics can be very useful in taxonomical, phylogenetic and ecological studies of M. ferruginea.

Behavioral responses of the small hive beetle, Aethina tumida, to odors of three meliponine bee species and honey bees, Apis mellifera scutellata

AbstractRecent studies have shown that honey bees, bumble bees, and some meliponine bee species of the genera Trigona, Meliponula, and Dactylurina are hosts of the small hive beetle (SHB) Aethina tumidaMurray (Coleoptera: Nitidulidae), a pest of honey bee colonies in various regions of the world. Olfaction has been implicated in SHB infestations of honey bee and bumble bee colonies. We used olfactometer bioassays to investigate responses of adult male and female SHBs to odors from intact colonies and separate hive components (pot honey, pot pollen, cerumen, and propolis) of three African meliponine bee species, Meliponula ferruginea (Lepeletier) (black morphospecies), M. ferruginea (reddish brown morphospecies), and Meliponula bocandei (Spinola) (Hymenoptera: Apidae). Although both sexes of the beetle strongly preferred intact colony, pot honey, and pot pollen odors, there was no evidence of attraction to propolis and cerumen odors from the three meliponine bee species. Both sexes of SHB also strongly preferred odors from honey bees, Apis mellifera L. (Hymenoptera: Apidae), over odors from the three meliponine bee species. Our results provide substantial evidence of the host potential of African meliponine bees for the SHB, and we discuss this complex association of the SHB with species within the Apidae family.

Forest Fragmentation Shapes Resource Partitioning for Endemic Pollinators (Hymenoptera: Meliponini)

A field study was undertaken along six diverse habitat gradients of Kenya to evaluate the occurrence and underlining drivers that shape meliponine bee species diversity. These gradients ranged from continuous forest habitats (Indigenous forests, mixed forests and exotic forest patch) representing unfragmented habitats to dispersed habitats (Mixed deciduous woodlands, Grasslands dominated by perennial grasses such as Cenchrus ciliaris, Chloris roxburghiana and Acacia dominated bush lands) representing fragmented habitats respectively. A total of four different species of meliponine bees were encountered with Hypotrigona gribodoi being the most abundant species, followed by Meliponula ferruginea (black), Plebeina hildebrandti and Hypotrigona ruspolii in descending order. Occurrence and diversity of Hypotrigona gribodoi, Melipona ferruginea (black), Plebeina hildebrandti and Hypotrigonaruspolii was significantly influenced by the degree of fragmentation (vegetation type) and floral diversity (P = 0.0056); the mean number of colonies recorded per study site ranged from 2.3 in dispersed habitats in the lowlands to 1.0 in continuous forest landscapes in the highlands, whereas the mean population density ranged from 2.0 to 172 colonies/25 ha-transects. The results provide substantial support to better understand interactions between habitat structure and the degree of fragmentation in linking species diversity to habitat loss.

Identification of stingless bees (Hymenoptera: Apidae) in Kenya using morphometrics and DNA barcoding

Stingless bees are important pollinators of wild plants and crops. The identity of stingless bee species in Africa has not been fully documented. The present study explored the utility of morphometrics and DNA barcoding for identification of African stingless bee populations, and to further employ these tools to identify potential cryptic variation within species. Stingless bee samples were collected from three ecological zones, namely Kakamega Forest, Mwingi and Arabuko-Sokoke Forest, which are geographically distant and cover high, medium and low altitudes, respectively. Forewing and hind leg morphometric characters were measured to determine the extent of morphological variation between the populations. DNA barcodes were generated from the mitochondrial cytochrome c-oxidase I (COI) gene. Principal Component Analysis (PCA) on the morphometric measurements separated the bee samples into three clusters: (1) Meliponula bocandei; (2) Meliponula lendliana + Plebeina hildebrandti; (3) Dactylurina schmidti + Meliponula ferruginea black + Meliponula ferruginea reddish brown, but Canonical Variate Analysis (CVA) separated all the species except the two morphospecies (M. ferruginea reddish brown and black). The analysis of the COI sequences showed that DNA barcoding can be used to identify all the species studied and revealed remarkable genetic distance (7.3%) between the two M. ferruginea morphs. This is the first genetic evidence that M. ferruginea black and M. ferruginea reddish brown are separate species.

Vulnerable Habitats Alter African Meliponine Bee's (Hymenoptera: Apidae) Assemblages in an Eastern Afromontane Biodiversity Hotspot.

Habitat degradation has over time formed synergy with other factors to contribute to dwindling populations of both fauna and flora by altering their habitats. The disturbance of natural habitats affects the diversity of both vertebrates and invertebrates by altering both feeding and nesting sites for which organisms are known to depend on for survival. Little is known of the extent to which vulnerable habitats could shape the diversity of most indigent pollinators such as African meliponine bee species in tropical ecosystems. This study was conducted to determine how disturbance could shape the natural occurrence of African meliponine bee species in different ecological habitats of Taita Hills, leading to changes in their diversity. A total of four species depicted by the Renyi diversity profile was recorded in five of the six main habitat types surveyed, and a further extrapolation with Shannon index (EH) also predicted the highest species richness of 4.24 in a deciduous habitat type. These meliponine bee species (Hypotrigona gribodoi, Hypotrigona ruspolii, Meliponula ferruginea (black), and Plebeina hildebrandti) were observed to be unevenly distributed across all habitats, further indicating that mixed deciduous habitat was more diverse than acacia-dominated bush lands, grasslands, and exotic forest patches. Geometric morphometrics categorized all four meliponine bee species into two major clusters—cluster 1 (H gribodoi, H ruspolii, M ferruginea (black)) and cluster 2 (P hildebrandti)—and further discriminated populations against the 4 potential habitats they are likely to persist or survive in. Each habitat appeared to consist of a cluster of subpopulations and may possibly reveal ecotypes within the four meliponine populations. This has revealed that unprecedented conversions of natural habitats to agroecosystems are a key driving factor causing increased habitat isolation and vulnerability in this Afromontane region which may potentially distort local assemblages of native pollinators, such as meliponine bee species.

Floral Resources Sustaining African Meliponine Bee Species (Hymenoptera: Meliponini) in a Fragile Habitat of Kenya

A vast majority of insects visit flowers for food, generally termed as floral rewards. Detailed insights on flowering phenology of plants could give a hint of habitat status and the extent to which such landscapes could support insect pollinators to render both direct and indirect ecosystem services. This study monitored flowering plants which could potentially provide both pollen and nectar sources to four African meliponine bee species (Apidae: Meliponini) naturally occurring in six diverse habitat gradients of the eastern arc mountains (Taita hills) of Kenya. Blooming sequences of identified flowering plants overlapped across seasons with approximately 80 different plant species belonging to 34 families recorded, with the highest proportions from Fabaceae and Asteraceae families dominating flowering plants that were visited (67% of the visits). A flowering calendar is presented to indicate the phenological pattern of all identified floral resources. Hypotrigona gribodoi being the most abundant species had the highest visitation rates on plants belonging to Fabaceae and Asteraceae families, followed by Meliponula ferruginea (black), Plebeina hildebrandti and Hypotrigona ruspolii. This indicates that such fragile habitat could invariably sustain nutritional requirements essential for the survival of insect pollinators such as native meliponine bee species, though bee abundance at flowers did not significantly correlate to food availability (expressed by flowering plant richness).

Olfactory associative learning in two African stingless bee species (Meliponula ferruginea and M. bocandei, Meliponini)

Worldwide only a few of the more than 500 stingless bee species has been studied in any detail. Most studies on stingless bees have been conducted in the Neotropics, whereas a very few have been undertaken in Africa. Foraging success is dependent to a greater or lesser extent on olfactory cues or signals. A prerequisite to effective foraging via odors is that the bees are able to associate odors with a nectar reward and memorize this information. In the context of olfactory learning, only five species of stingless bees have been studied using classical conditioning of the proboscis extension reflex (PER). Foragers are capable of using previously experienced olfactory information when choosing food sources, but they rarely respond in differential PER assays. This study examines for the first time the olfactory learning abilities of African stingless bees. A differential conditioning assay was used to study learning and memory of Meliponula ferruginea and Meliponula bocandei. Our results clearly show that both stingless bee species associate odors with a reward. Learning performance of both stingless bee species was poor compared to Apis m. scutellata. This might reflect that the experimental procedure has been optimized for Apis mellifera. However, the PER paradigm seems to be suitable to study learning, memory, and olfactory perception in Meliponula. As in honeybees, this paradigm will open the way to answer ecological, psychological, and neurobiological questions in these species.

Retraction Note: Patterns of bee diversity in mosaic agricultural landscapes of central Uganda: implication of pollination services conservation for food security

Little is known about bee communities and pollination services conservation strategies in sub-Sahara Africa. A study was conducted at 26 different sites with varying local landscape characteristics in farmlands of central Uganda in 2006. Bees were sampled using coloured pantraps, handnet and line transect counts. Overall 80,883 bee individuals from 6 families and 652 species were encountered. The bee fauna was characterized by a lower diversity of Melittidae and Andrenidae and a high diversity of Apidae, Megachilidae and Halictidae. Megachile and Lasioglossum were the two most species-rich genera. The most abundant species was Apis mellifera adansonii Linnaeus (23 % of total individuals) followed by Hypotrigona gribodoi Magretti (19 %), Meliponula ferruginea Lepeletier (13 %), Lasioglossum ugandicum Cockerell (7 %), Apis mellifera scutellata Latreille (6 %), Allodapula acutigera Cockerell (6 %), Ceratina rufigastra Cockerell (5 %), Ceratina tanganyicensis Strand (5 %), Braunsapis angolensis Cockerell (5 %), Megachile rufipes Fabricius (5 %), Meliponula bocandei Spinola (5 %) and Seladonia jucundus Smith (5 %). The mean number of species recorded per study site per day ranged between 14 and 49, whereas the abundance ranged between 188 and 1,859 individuals. Study sites in areas with intense land-use had species-poor bee communities compared to sites with medium to low land-use intensities. Study sites with riparian forest fragments and wetlands, or with forest fallows in their vicinity had significantly (P < 0.05) higher species richness and diversity than sites dominated by small-scale monoculture/polyculture fields or sites dominated by either simple or complex traditional agroforestry systems. An ordination analysis also revealed that bee communities were significantly (P < 0.01) influenced by the presence of semi-natural habitats (woodlands, fallows) and forest fragments in the surrounding of fields. Thus, natural and semi-natural habitats are of great value for afrotropical farmland bee communities. There is a need to put in place strategies and policies for semi-natural and forest fragments preservation for spatio-temporal stability of pollination services in rural landscapes. Farmers are recommended to increase on-farm trees cover to safeguard and enhance pollination function and services in fields. Mimicking natural vegetation through promoting establishment of forest plantations and village community forestry in rural landscapes is also critical for conserving pollination services.