An ancient pollinator of a contemporary plant (Cyclamen persicum): When pollination syndromes break down

Pollination of Cyclamen persicum (Primulaceae) was studied in two wild populations in Israel. Buzz-pollination proved to be extremely rare, and performed by a large Anthophora bee only. The most frequent pollinators were various unspecialized species of thrips (Thysanoptera) and hoverflies (Syrphidae). In the Winter-flowering populations the commonest visitor was a small primitive moth, Micropteris elegans (Micropterigidae, Lepidoptera). These moths feed on pollen, copulate and oviposit within the flowers. From the rarity of buzz-pollination it is concluded that the genus Cyclamen co-evolved with large bees capable of buzz-pollination, but lost its original pollinators for unknown historical reasons. The vacant niche was then open to various unspecialized pollen consumers such as thrips, hoverflies and small solitary bees. While these insects are not specific to C. persicum and seem to play a minor role only, the moth strictly relies upon Cyclamen and seems to be the most efficient pollinator.

Floral visitors and reproductive strategies in five melittophilous species of Bignoniaceae in Southeastern Brazil

Com objetivo de avaliar as estratégias de polinização de espécies de Bignoniaceae, foram estudados a biologia floral e os visitantes florais de cinco espécies, três arbustivas do cerrado (Arrabidaea brachypoda (DC.) Bor., Jacaranda decurrens Cham. e Jacaranda oxyphylla Cham.) e duas lianas da orla da floresta estacional semidecidual (Arrabidaea samydoides (Cham.) Sandw. e Arrabidaea triplinervia H. Baill.), na região de Botucatu (22º52'20 S e 48(0)26'37 W), estado de São Paulo, sudeste do Brasil. Os períodos de florescimento, principalmente entre espécies do mesmo habitat, apresentaram sobreposição parcial. Observou-se que as cinco espécies são alogâmicas funcionais, melitófilas, nototríbicas, polinizadas principalmente por abelhas grandes de língua comprida. Algumas abelhas coletoras de pólen de tamanho médio e pequeno atuaram como polinizadoras ocasionais, enquanto outros visitantes foram pilhadores. Cada uma das Bignoniaceae apresentou um conjunto particular de polinizadores havendo apenas duas espécies comuns a mais de uma delas. Não houve partilha de polinizadores mesmo entre bignoniáceas que, no mesmo habitat, apresentaram períodos de florescimento simultâneo.

Pollination ecology of the Cerrado species Eschweilera nana (Lecythidaceae subfam. Lecythidoideae)

Eschweilera nana is pollinated by a guild of pollinators consisting of mostly bees. Effective pollinators are large bees able to force their way into the closed androecium to access nectar. The morphology of the flowers diminishes self pollination and promotes cross-pollination. Although many pollinators make diurnal visits to the flowers, fruit set was very low in comparison with the number of flowers produced. Breeding system tests yielded only two fruits, one produced by xenogamy and another one in the control test. The results of this study are consistent with studies of other Cerrado plants pollinated by guilds of insects and support the conclusion of other pollination studies of Lecythidaceae that fruit set is low in comparison with the high numbers of flowers produced. © 2013 The New York Botanical Garden.

Ecologia da polinização de Eschweilera nana Miers, uma Lecythidaceae do cerrado

Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

Large-Range Movements of Neotropical Orchid Bees Observed via Radio Telemetry

Neotropical orchid bees (Euglossini) are often cited as classic examples of trapline-foragers with potentially extensive foraging ranges. If long-distance movements are habitual, rare plants in widely scattered locations may benefit from euglossine pollination services. Here we report the first successful use of micro radio telemetry to track the movement of an insect pollinator in a complex and forested environment. Our results indicate that individual male orchid bees (Exaerete frontalis) habitually use large rainforest areas (at least 42-115 ha) on a daily basis. Aerial telemetry located individuals up to 5 km away from their core areas, and bees were often stationary, for variable periods, between flights to successive localities. These data suggest a higher degree of site fidelity than what may be expected in a free living male bee, and has implications for our understanding of biological activity patterns and the evolution of forest pollinators.

Visual ecology of Indian carpenter bees II: adaptations of eyes and ocelli to nocturnal and diurnal lifestyles

Most bees are diurnal, with behaviour that is largely visually mediated, but several groups have made evolutionary shifts to nocturnality, despite having apposition compound eyes unsuited to vision in dim light. We compared the anatomy and optics of the apposition eyes and the ocelli of the nocturnal carpenter bee, Xylocopa tranquebarica, with two sympatric species, the strictly diurnal X. leucothorax and the occasionally crepuscular X. tenuiscapa. The ocelli of the nocturnal X. tranquebarica are unusually large (diameter ca. 1 mm) and poorly focussed. Moreover, their apposition eyes show specific visual adaptations for vision in dim light, including large size, large facets and very wide rhabdoms, which together make these eyes 9 times more sensitive than those of X. tenuiscapa and 27 times more sensitive than those of X. leucothorax. These differences in optical sensitivity are surprisingly small considering that X. tranquebarica can fly on moonless nights when background luminance is as low as 10(-5) cd m(-2), implying that this bee must employ additional visual strategies to forage and find its way back to the nest. These strategies may include photoreceptors with longer integration times and higher contrast gains as well as higher neural summation mechanisms for increasing visual reliability in dim light.

Warfare in stingless bees

Bees are well known for being industrious pollinators. Some species, however, have taken to invading the nests of other colonies to steal food, nest material or the nest site itself. Despite the potential mortality costs due to fighting with an aggressive opponent, the prospects of a large bounty can be worth the risk. In this review, we aim to bring together current knowledge on intercolony fighting with a view to better understand the evolution of warfare in bees and identify avenues for future research. A review of literature reveals that at least 60 species of stingless bees are involved in heterospecific conflicts, either as attacking or victim colonies. The threat of invasion has led to the evolution of architectural, behavioural and morphological adaptations, such as narrow entrance tunnels, mud balls to block the entrance, decoy nests that direct invaders away from the brood chamber, fighting swarms, and soldiers that are skilled at immobilising attackers. Little is known about how victim colonies are selected, but a phylogenetically controlled analysis suggests that the notorious robber bee Lestrimelitta preferentially attacks colonies of species with more concentrated honey. Warfare among bees poses many interesting questions, including why species differ so greatly in their response to attacks and how these alternative strategies of obtaining food or new nest sites have evolved.

A sting in the spit: widespread cross-infection of multiple RNA viruses across wild and managed bees

Declining populations of bee pollinators are a cause of concern, with major repercussions for biodiversity loss and food security. RNA viruses associated with honeybees represent a potential threat to other insect pollinators, but the extent of this threat is poorly understood. This study aims to attain a detailed understanding of the current and ongoing risk of emerging infectious disease (EID) transmission between managed and wild pollinator species across a wide range of RNA viruses. Within a structured large-scale national survey across 26 independent sites, we quantify the prevalence and pathogen loads of multiple RNA viruses in co-occurring managed honeybee (Apis mellifera) and wild bumblebee (Bombus spp.) populations. We then construct models that compare virus prevalence between wild and managed pollinators. Multiple RNA viruses associated with honeybees are widespread in sympatric wild bumblebee populations. Virus prevalence in honeybees is a significant predictor of virus prevalence in bumblebees, but we remain cautious in speculating over the principle direction of pathogen transmission. We demonstrate species-specific differences in prevalence, indicating significant variation in disease susceptibility or tolerance. Pathogen loads within individual bumblebees may be high and in the case of at least one RNA virus, prevalence is higher in wild bumblebees than in managed honeybee populations. Our findings indicate widespread transmission of RNA viruses between managed and wild bee pollinators, pointing to an interconnected network of potential disease pressures within and among pollinator species. In the context of the biodiversity crisis, our study emphasizes the importance of targeting a wide range of pathogens and defining host associations when considering potential drivers of population decline.

Behaviour and life history of a large carpenter bee (Xylocopa virginica) in the northern extent of its range

Large carpenter bees (Hymenoptera: Apidae: Xylocopa) have traditionally been thought of as exhibiting solitary or occasionally communal colony social organization. However, studies have demonstrated more complex fonns of social behaviour in this genus. In this document, I examine elements ofbehaviour and life history in a North American species at the northern extreme of its range. Xylocopa virginica was found to be socially polymorphic with both solitary and meta-social or semi-social nests in the same population. In social nests, there is no apparent benefit from additional females which do not perfonn significant work or guarding. I found that the timing of life-history events varies between years, yet foraging effort only differed in the coldest and wettest year of2004 the study. Finally, I that male X virginica exhibit female defence polygyny, with resident and satellite males. Resident males maintain their territories through greater aggression relative to satellites.

Nestmate recognition in the large carpenter bee, Xylocopa virginica /

Abstract Many species of social insects have the ability to recognize their nestmates. In bees, sociality is maintained by bees that recognize which individuals should be helped and which should be hanned in order to maximize fitness (either inclusive or individual) (Hamilton 1964; Lin and Michener 1972). Since female bees generally lay eggs in a single nest, it is highly likely that bees found cohabitating in the same nest are siblings. According to the kin selection hypothesis, individuals should cooperate and avoid aggression with same sex nestmates (Hamilton 1964). However, in opposite sex pairs that are likely kin, aggression should increase among nestmates as an expression of inbreeding avoidance (Lihoreau et al. 2007). Female bees often guard nest entrances, recognizing and excluding foreign conspecific females that threaten to steal nest resources (Breed and Page 1991). Conversely, males that aggressively guard territories should avoid aggression towards other males that are likely kin (Shellman-Reeve and Gamboa 1984). In order to test whether Xy/ocopa virginica can distinguish nestmates from non-nestmates, circle tube testing arenas were used. Measures of aggression, cooperation and tolerance were evaluated to detennine the presence of nestmate recognition in this species. The results of this study indicate that male and female X virginica have the ability to distinguish nestmates from non-nestmates. Individuals in same sex pairs demonstrated increased pushing, biting, and C-posturing when faced with non-nestmates. Males in same sex pairs also attempted to pass (unsuccessfully) nOIl-nestmates more often than ncstmates, suggesting that this behaviour may be an cxpression of dominancc in males. Increased cooperation exemplified by successful passes was not observed among nestmates. However, incrcased tolerance in the [onn of head-to-head touching was observed for nestmates in female same sex and opposite sex pairs. These results supported the kin selection hypothesis. Moreover, increased tolerance among opposite sex non-nestmates suggested that X virginica do not demonstrate inbreeding avoidance among nestmates. 3 The second part of this study was conducted to establish the presence and extent of drifting, or travelling to different nests, in a Xylocopa virgillica population. Drifting in flying Hymenoptera is reported to be the result of navigation error and guard bees erroneously admitting novel individuals into the nest (Michener 1966). Since bees in this study were individually marked and captured at nest entrances, the locations where individuals were caught allowed me to determine where and how often bees travelled from nest to nest. Ifbees were captured near their home nests, changing nests may have been deliberate or explained by navigational error. However, ifbees were found in nests further away from their homes, this provides stronger evidence that flying towards a novel nest may have been deliberate. Female bees are often faithful to their own nests (Kasuya 1981) and no drifting was expected in female X virginica because they raise brood and contribute to nest maintenance activities. Contrary to females, males were not expected to remain faithful to a single nest. Results showed that many more females drifted than expected and that they were most often recaptured in a single nest, either their home nest or a novel nest. There were some females that were never caught in the same nest twice. In addition, females drifted to further nests when population density was low (in 2007), suggesting they seek out and claim nesting spaces when they are available. Males, as expected, showed the opposite pattern and most males drifted from nest to nest, never recaptured in the same location. This pattern indicates that males may be nesting wherever space is available, or nesting in benches nearest to their territories. This study reveals that both female and male X virginica are capable of nestmate recognition and use this ability in a dynamic environment, where nest membership is not as stable as once thought.

Dispersal capacity and diet breadth modify the response of wild bees to habitat loss

Habitat loss poses a major threat to biodiversity, and species-specific extinction risks are inextricably linked to life-history characteristics. This relationship is still poorly documented for many functionally important taxa, and at larger continental scales. With data from five replicated field studies from three countries, we examined how species richness of wild bees varies with habitat patch size. We hypothesized that the form of this relationship is affected by body size, degree of host plant specialization and sociality. Across all species, we found a positive species–area slope (z ¼ 0.19), and species traits modified this relationship. Large-bodied generalists had a lower z value than small generalists. Contrary to predictions, small specialists had similar or slightly lower z value compared with large specialists, and small generalists also tended to be more strongly affected by habitat loss as compared with small specialists. Social bees were negatively affected by habitat loss (z ¼ 0.11) irrespective of body size. We conclude that habitat loss leads to clear shifts in the species composition of wild bee communities.

Abundance and diversity of wild bees along gradients of heavy metal pollution

1. Wild bees are one of the most important groups of pollinators in the temperate zone. Therefore, population declines have potentially negative impacts for both crop and wildflower pollination. Although heavy metal pollution is recognized to be a problem affecting large parts of the European Union, we currently lack insights into the effects of heavy metals on wild bees. 2. We investigated whether heavy metal pollution is a potential threat to wild bee communities by comparing (i) species number, (ii) diversity and (iii) abundance as well as (iv) natural mortality of emerging bees along two independent gradients of heavy metal pollution, one at Olkusz (OLK), Poland and the other at Avonmouth (AVO), UK. We used standardized nesting traps to measure species richness and abundance of wild bees, and we recorded the heavy metal concentration in pollen collected by the red mason bee Osmia rufa as a measure of pollution. 3. The concentration of cadmium, lead and zinc in pollen collected by bees ranged from a background level in unpolluted sites [OLK: 1·3, 43·4, 99·8 (mg kg−1); AVO: 0·8, 42·0, 56·0 (mg kg−1), respectively] to a high level on sites in the vicinity of the OLK and AVO smelters [OLK: 6·7, 277·0, 440·1 (mg kg−1); AVO: 9·3, 356·2, 592·4 (mg kg−1), respectively]. 4. We found that with increasing heavy metal concentration, there was a steady decrease in the number, diversity and abundance of solitary, wild bees. In the most polluted sites, traps were empty or contained single occupants, whereas in unpolluted sites, the nesting traps collected from 4 to 5 species represented by up to ten individuals. Moreover, the proportion of dead individuals of the solitary bee Megachile ligniseca increased along the heavy metal pollution gradient at OLK from 0·2 in uncontaminated sites to 0·5 in sites with a high concentration of pollution. 5. Synthesis and applications. Our findings highlight the negative relationship between heavy metal pollution and populations of wild bees and suggest that increasing wild bee richness in highly contaminated areas will require special conservation strategies. These may include creating suitable nesting sites and sowing a mixture of flowering plants as well as installing artificial nests with wild bee cocoons in polluted areas. Applying protection plans to wild pollinating bee communities in heavy metal-contaminated areas will contribute to integrated land rehabilitation to minimize the impact of pollution on the environment.

Behavioral suites mediate group-level foraging dynamics in communities of tropical stingless bees

Competition for floral resources is a key force shaping pollinator communities, particularly among social bees. The ability of social bees to recruit nestmates for group foraging is hypothesized to be a major factor in their ability to dominate rich resources such as mass-flowering trees. We tested the role of group foraging in attaining dominance by stingless bees, eusocial tropical pollinators that exhibit high diversity in foraging strategies. We provide the first experimental evidence that meliponine group foraging strategies, large colony sizes and aggressive behavior form a suite of traits that enable colonies to improve dominance of rich resources. Using a diverse assemblage of Brazilian stingless bee species and an array of artificial ""flowers"" that provided a sucrose reward, we compared species` dominance and visitation under unrestricted foraging conditions and with experimental removal of group-foraging species. Dominance does not vary with individual body size, but rather with foraging group size. Species that recruit larger numbers of nestmates (Scaptotrigona aff. depilis, Trigona hyalinata, Trigona spinipes) dominated both numerically (high local abundance) and behaviorally (controlling feeders). Removal of group-foraging species increased feeding opportunities for solitary foragers (Frieseomelitta varia, Melipona quadrifasciata and Nannotrigona testaceicornis). Trigona hyalinata always dominated under unrestricted conditions. When this species was removed, T. spinipes or S. aff. depilis controlled feeders and limited visitation by solitary-foraging species. Because bee foraging patterns determine plant pollination success, understanding the forces that shape these patterns is crucial to ensuring pollination of both crops and natural areas in the face of current pollinator declines.

Morphometric analysis of the venom gland in worker bees of Apis mellifera (Hymenoptera : Apidae) from the pantanal region of Mato Grosso do Sul

In Apis mellifera the acid or venom gland is composed of secretory cells that surround a channel that opens into a reservoir devoid of musculature. This gland can at times present apical branching. In this study we recorded the frequency of branched venom glands in workers of Africanized bees (Apis mellifera Linnaeus) from six localities in the Pantanal region of Mato Grosso do Sul, and analyzed the relation among the length of the main duct, the length of the duct from the reservoir to the beginning of branching, the length of the branched segment (when present) and the total length of the gland. We sought to determine the probable genotypes of the bees from each population by using the model proposed by Alves-Junior. The frequency of branched glands varied from 50% to 83% in the worker bees coming from those places, indicating that this characteristic is primitive in these bees. The results of the Analysis of Discriminant Functions indicated significant differences in the morphometrical segments of the venom gland (Wilk's Lambda = 0.065; F-(27,F-30) = 4.507; P < 0.001), and permitted a differentiation of the populations studied. The genotypes inferred for the bees of each locality agree with the results obtained in the Analysis of Discriminant Functions and form three distinct groups, with some overlapping areas among them. In all of the populations considered the phenotype largevenom gland was predominant. It is inferred that bees with this phenotype (venom gland larger than S. 15 mm) have Gm(1) Gm(1) genotype, being therefore homozygotes for the major alleles and also for the modifier genes that codify this morphological trait. The high frequency of worker bees with large venom gland in all the places considered makes viable the development of a selection program in order to obtain bees with longer venom glands, aimed at the commercial production of venom by the beekeepers of the Pantanal region of Mato Grosso do Sul.

Cytoplasmic protrusions from digestive cells of bees

Midgut cells from the honey bee, Apis mellifera, and the stingless bees Scaptotrigona postica and Melipona quadrifasciata anthidioides were examined ultrastructurally and histochemically. Several types of protrusions were evident in the apical surface of the midgut cells. Large apical protrusions formed by the whole apical surface of the cell, whose content had a homogeneous cytoplasmic matrix devoid of organelles and with a different electron density from the subjacent cytoplasm. These protrusions can be cast out to the midgut lumen. A second type of large apical protrusion was produced between the cell microvilli, presenting many ribosomes and polyribosomes. In addition to these large protrusions two other kinds of small ones were observed. One type crowned the cell apex forming small spheres with irregular contours near the cells, and increasing in size further away. The other type was characterized by the microvilli swelling with an electron-lucent content. The Gomori acid phosphatase reaction was positive at the cell apex, in the pinched off protrusions and in the microvilli. These results are discussed in relation to the possible role of cell protrusions in secretory mechanisms.