1. New incentives at the national and international level frequently lead to substantial structural changes in agricultural landscapes. Subsidizing energy crops, for example, recently fostered a ...strong increase in the area cultivated with oilseed rape Brassica napus across the EU. These changes in landscape structure affect biodiversity and associated ecosystem services. 2. Mass-flowering oilseed rape has been shown to positively affect colony growth and densities of bumblebees, which may enhance pollination services in agroecosystems. Not considered, however, have been species-specific traits of pollinators resulting in disproportionate benefits from these recurrent resource pulses. A subsequent community shift towards the subsidized species potentially distorts plant-pollinator interactions in the surrounding landscape. 3. We analysed the effects of mass-flowering crops on the abundance of legitimate long-tongued bumblebee pollinators, nectar robbing by illegitimate short-tongued bumblebees and seed set in the long-tubed flowers of red clover Trifolium pratense in 12 landscape sectors with differing amounts of oilseed rape. 4. Densities of long-tongued bumblebees visiting long-tubed plants decreased with increasing amounts of oilseed rape. The simultaneous increase of nectar robbing suggests that resource depletion is a likely explanation for this decline which may lead to a distortion in plant-pollinator interactions. The decline in long-tongued bumblebees, however, did not result in an immediate effect on seed set. In contrast, seed set increased with increasing amounts of semi-natural habitats, indicating the positive effects of these habitats on the legitimate long-tongued pollinators. 5.Synthesis and applications. Accounting for species-specific traits is essential in evaluating the ecological impacts of land-use change. The disproportional trait-specific benefits of increasing oilseed rape to short-tongued bumblebees may abet an increasingly pollinator-dependent agriculture but simultaneously threaten the more specialized and rare long-tongued species and their functions. Semi-natural habitats were found to positively affect seed set in long-tubed plants indicating that they can counteract the potentially distorting effects of transient mass-flowering crops on plant-pollinator interactions in agroecosystems. Future agri-environmental schemes should aim to provide diverse and continuous resources matching trait-specific requirements of various pollinators in order to avoid resource competition. Thereby they harmonize the economic interest in abundant pollinators and the conservation interest in protecting rare species.
In Uruguay, the production of tomato (Solanum lycopersicum) in greenhouse presents pollination issues that limit its yield. The use of bumblebees (Bombus spp.) as pollinators can help overcome this ...problem as they perform “buzzing pollination”, a behavior that makes them excellent pollinators of Solanaceae and particularly tomato. The aim of this study was to evaluate the effect of the native bumblebees Bombus atratus on the proportion of fruit set, weight, diameter, number of seeds and number of locules of tomato (lapataia and elpida varieties). An experience was carried out in Canelones, where the fruits from flowers pollinated by bumblebees and from flowers not visited by insects were compared; two other experiences carried out in Salto were similar to that of Canelones, but included flowers treated with hormones. In the three analyzed greenhouses the visit of bumblebees to the flowers increased the proportion of fruit set by 13 - 47%, compared to the result obtained in flowers not visited by the insects. Also, the pollinating action of bumblebees significantly improved the weight, size, and number of seeds compared to fruits obtained from flowers without access to pollinators. This improvement was recorded in the experience in Canelones and only in one of the Salto's experiences. On the other hand, a positive correlation was found between the number of seeds and the weight (R2 = 0.37, R2 = 0.53; lapataia, elpida, respectively) in the two tomato varieties. This study is the first in Uruguay to show the benefits of using native bumblebees in tomato production in greenhouses.
Citizen science can provide a valuable tool for collecting large quantities of ecological data over a larger geographic area than would otherwise be possible. Here, data were collected on 1,022 ...bumblebee nests by means of a public survey in which participants were asked to record attributes of bumblebee nests discovered in their gardens. All commonly reported species appeared to be generalist in their nest site selection and though species-specific differences in nest site choice were evident, there was a high degree of overlap in nesting habitat between most species. There was little evidence supporting the hypothesis that bumblebees tend to nest in the same site in consecutive years. A comparison of the contributions made by different species to the total nests reported in this and previous similar surveys suggests that the common bumblebee species
Bombus pascuorum
may have declined over the past 20 years relative to other species, comprising ~21% of colonies discovered in a survey conducted in 1989–1991, but just 8–9% of colonies in 2007–2009. This was accompanied by a reduction in the proportion of nests on the ground surface (the preferred position of this species). This is the first quantitative evidence of potential declines in the one of the UK’s ‘big six’ common bumblebee species.
To determine the presence and the prevalence of four different honeybee viruses (acute bee paralysis virus—ABPV, black queen cell virus—BQCV, chronic bee paralysis virus—CBPV, deformed wing ...virus—DWV) in wild bumblebees, pooled randomly selected bumblebee samples were collected from twenty-seven different locations in the territory of Croatia. All samples were prepared and examined using the RT-PCR methods for quantification of mentioned honeybee viruses. Determined prevalence (%) of identified positive viruses were in the following decreasing order: BQCV > DWV > ABPV, CBPV. Additionally, direct sequencing of samples positive for BQCV (n = 24) and DWV (n = 2) was performed, as well as a test of molecular phylogeny comparison with those available in GenBank. Selected positive field viruses’ strains showed 95.7 to 100% (BQCV) and 98.09% (DWV) nucleotide identity with previously detected and deposited honeybee virus strains in the geographic areas in Croatia and neighboring Slovenia. In this article, the first detection of four honeybee viruses with genetic characterization of high diversity strains circulating in wild bumblebees in Croatia is presented.
‘Conference’ (Pyrus communis L.) is a self-incompatible cultivar, although it can also set fruit parthenocarpically. Stimulating parthenocarpy through gibberellin (GA) applications increases the ...fruit set, but it may also negatively affect the fruit size and shape. The aim of this study was to investigate the effects of a bumblebee (BB) amendment in combination with a GA treatment on the fruit set and fruit shape of ‘Conference’ pears. In the first experiment, we applied three treatments (GA, GA + BB & control) in a ‘Conference’ monoculture. In the second experiment, we applied two treatments (GA & GA + BB) in a ‘Conference’ orchard inter-planted with ‘Concorde’ as pollinizer trees. Both experiments showed that the GA application and bumblebee supplementation did not affect the fruit set. However, the BB treatment resulted in significantly higher amounts of normally shaped pears. Trees closer to the bumblebee hive had more normal shaped pears than trees further away.
Flowering, nectar secretion, and pollen production in Hyacinthus orientalis ‘Sky Jacket’ (Asparagaceae) were studied between 2013 and 2015 in Lublin, SE Poland (51°16' N, 22°30' E). The flowering was ...weather-dependent. It started at the beginning of April or at the end of the month and lasted 14–24 days. The mass of nectar, sugar concentration in the nectar, nectar sugar mass, anther size, and pollen mass in flowers all depended on the flower position in the inflorescence and differed significantly between the years of study. The greatest mass of sugars and pollen was recorded in low-positioned flowers. On average, H. orientalis ‘Sky Jacket’ produced 1.63 mg of sugars and 3.51 mg of pollen per flower. The floral reward was attractive for Apis mellifera and Bombus spp., which indicate that the species should be propagated not only for its decorative value but also for supporting pollinators in early spring.
Honey bee pathogens are spread worldwide and are strongly related to the decline of honey bee populations, which has severe implications for beekeeping, honey production and ecology. Honey bee ...pathogens are continuously studied by researchers with the aim to better understand the host–parasite relationship of these pathogens and the effects that they have on bee colonies. Honey bee pathogens include bacteria (i.e., Melissococcus plutonius and Paenibacillus larvae), microsporidia (i.e., Nosema apis and Nosema ceranae), fungi (i.e., Ascosphaera apis), protozoa (i.e., Lotmaria passim, Crithidia bombi and Crithidia mellificae) and viruses (i.e., ABPV, CBPV, IAPV, KBV, DWV, BQCV and SBV). All of these pathogens are able to infect other bee species; infections would have important implications for their life cycles (e.g., Osmia sp. and Bombus sp.) or cause unknown epidemiological effects for other hymenopterans. In addition, old and new invasive pests (such as Varroa destructor, Aethina tumida, Vespa velutina, etc.) necessitate more studies to define their role as possible vectors or possible sources of infection for honey bees. For these reasons, knowledge on honey bee pathogens has become a matter of public interest and is connected with the critical role of honey bee health. The aim of this Special Issue is to explore honey bee pathogens, considering any aspect in relation to host–pathogen interaction and highlighting the possible interaction and spillover with other bee species and invasive pests, through a series of research articles that focus on different aspects of pathologies.
As the human population has increased, so too has the demand for biotically pollinated crops. Bees (Apoidea) are essential for pollen transfer and fruit production in many crops, and their visit ...patterns can be influenced by floral morphology. Here, we considered the role of floral morphology on visit rates and behaviour of managed honey bees (Apis mellifera) and wild bumble bees (genus Bombus), for four highbush blueberry cultivars (Vaccinium corymbosum L.). We measured five floral traits for each cultivar, finding significant variation among cultivars. Corolla throat diameter may be the main morphological determinant of visit rates of honey bees, which is significantly higher on the wider flowers of cv. ‘Duke’ than on ‘Bluecrop’ or ‘Draper’. Honey bees also visited cv. ‘Duke’ legitimately but were frequent nectar robbers on the long, narrow flowers of cv. ‘Bluecrop’. Bumble bees were infrequent (and absent on cv. ‘Draper’) but all observed visits were legitimate. Crop yield was highest for the cultivar with the highest combined (honey bee + bumble bee) visit rate, suggesting that aspects of floral morphology that affect pollinator visit patterns should be considered in crop breeding initiatives.
We conducted a bee survey in neonicotinoid-treated commercial potato fields using bowl and vane traps in the 2016 growing season. Traps were placed outside the fields, at the field edges, and 10 and ...30 m into the fields. We collected 756 bees representing 58 species, with
spp. comprising 73% of all captured bees. We found seven
spp., of which
was the only known visitor of potato flowers in our region. The majority of the bees (68%) were collected at the field edges and in the field margins. Blue vane traps caught almost four-times as many bees and collected 30% more species compared to bowl traps. Bee communities did not differ across trap locations but they were different among trap types. We tested
visitation to neonicotinoid treated and untreated potato flowers in field enclosures. The amount of time bees spent at flowers and the duration of visits were not significantly different between the two treatments. Our results demonstrate that a diverse assemblage of bees is associated with an agroecosystem dominated by potatoes despite the apparent lack of pollinator resources provided by the crop. We found no difference in
foraging behavior on neonicotinoid-treated compared to untreated plants.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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