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  1. Commercially reared cavity-nesting bees have been studied mainly in large, intensively managed orchards. However, knowledge on wild cavity-nesting bee and wasp communities and their potential limitations in smaller orchards remain insufficient.
  2. We compared the colonization rate of trapnests, nesting success, parasitism and response to flower resources of cavity-nesting bees and wasps between apple orchards and nearby semi-natural habitats (SNHs).
  3. Trapnests were placed in orchards and neighbouring SNHs. Colonization dynamics were studied and herbaceous flower resources were estimated. Furthermore, nest and brood cell quantity, number of alive offspring and nest parasitism rate were assessed.
  4. We found a higher colonization rate in the SNHs than in the orchards. Both bees and wasps made more nests, completed more brood cells and had a higher number of alive offspring in the SNHs. The number of bee nests in the orchards showed a positive correlation with the species richness of the flowering plants. The nest parasitism of wasps was higher in the SNHs.
  5. Apple orchards in the studied small-scale system were generally less colonized by cavity-nesting hymenopterans than nearby SNHs that can be important reservoirs of these ecosystem service provider hymenopterans. Our results highlight the importance of diverse flowering herbaceous vegetation in the understory that increased the number of bee nests in orchards and that could have a positive effect on the nesting activity of the bee species active in summer. Therefore, management practices that support flowering plant species in the understory vegetation are highly recommended in such orchards.
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3.
Wild bees provide vital pollination services for many native and agricultural plant species, yet the landscape conditions needed to support wild bee populations are not well understood or appreciated. We assessed the influence of landscape composition on bee abundance and species richness in apple (Malus spp.) orchards of northeastern Wisconsin during the spring flowering period. A diverse community of bee species occurs in these apple orchards, dominated by wild bees in the families Andrenidae and Halictidae and the honey bee, Apis mellifera L. Proportion of forest area in the surrounding landscape was a significant positive predictor of wild bee abundance in orchards, with strongest effects at a GIS (Geographic Information Systems) buffer distance of 1,000 m or greater. Forest area also was positively associated with species richness, showing strongest effects at a buffer distance of 2,000 m. Nonagricultural developed land (homes, lawns, etcetera) was significantly negatively associated with species richness at buffer distances >750 m and wild bee abundance in bowl traps at all distances. Other landscape variables statistically associated with species richness or abundance of wild bees included proportion area of pasture (positive) and proportion area of roads (negative). Forest area was not associated with honey bee abundance at any buffer distance. These results provide clear evidence that the landscape surrounding apple orchards, especially the proportion of forest area, affects richness and abundance of wild bees during the spring flowering period and should be a part of sustainable land management strategies in agro-ecosystems of northeastern Wisconsin and other apple growing regions.  相似文献   

4.
Wild bees are declining in intensively farmed regions worldwide, threatening pollination services to flowering crops and wild plants. To halt bee declines, it is essential that conservation actions are based on a mechanistic understanding of how bee species utilize landscapes. We aimed at teasing apart how foraging resources in the landscape through the nesting season affected nesting and reproduction of a solitary bee in a farmland region. We investigated how availability of floral resources and potentially resource‐rich habitats surrounding nests affected nest provisioning and reproduction in the solitary polylectic bee Osmia bicornis. The study was performed in 18 landscape sectors dominated by agriculture, but varying in agricultural intensity in terms of proportion of organic crop fields and seminatural permanent pastures. Pasture‐rich sectors contained more oak (Quercus robur), which pollen analysis showed to be favored forage in early season. More oaks ≤100 m from nests led to higher proportions of oak pollen in nest provisions and increased speed of nest construction in early season, but this effect tapered off as flowering decreased. Late‐season pollen foraging was dominated by buttercup (Ranunculus spp.), common in various noncrop habitats. Foraging trips were longer with more oaks and increased further through the season. The opposite was found for buttercup. Oak and buttercup interacted to explain the number of offspring; buttercup had a positive effect only when the number of oaks was above the mean for the studied sectors. The results show that quality of complex and pasture‐rich landscapes for O. bicornis depends on preserving existing and generating new oak trees. Lignose plants are key early‐season forage resources in agricultural landscapes. Increasing habitat heterogeneity with trees and shrubs and promoting suitable late‐flowering forbs can benefit O. bicornis and other wild bees active in spring and early summer, something which existing agri‐environment schemes seldom target.  相似文献   

5.
Wild bees are threatened by multiple interacting stressors, such as habitat loss, land use change, parasites, and pathogens. However, vineyards with vegetated inter‐rows can offer high floral resources within viticultural landscapes and provide foraging and nesting habitats for wild bees. Here, we assess how vineyard management regimes (organic vs. conventional; inter‐row vegetation management) and landscape composition determine the inter‐row plant and wild bee assemblages, as well as how these variables relate to functional traits in 24 Austrian and 10 South African vineyards. Vineyards had either permanent vegetation cover in untilled inter‐rows or temporary vegetation cover in infrequently tilled inter‐rows. Proportion of seminatural habitats (e.g., fallows, grassland, field margins) and woody structures (e.g., woodlots, single trees, tree rows) were used as proxies for landscape composition and mapped within 500‐m radius around the study vineyards. Organic vineyard management increased functional richness (FRic) of wild bees and flowering plants, with woody structures marginally increasing species richness and FRic of wild bees. Wild bee and floral traits were differently associated across the countries. In Austria, several bee traits (e.g., lecty, pollen collection type, proboscis length) were associated with flower color and symmetry, while in South African vineyards, only bees’ proboscis length was positively correlated with floral traits characteristic of Asteraceae flowers (e.g., ray–disk morphology, yellow colors). Solitary bee species in Austria benefitted from infrequent tillage, while ground nesting species preferred inter‐rows with undisturbed soils. Higher proportions of woody structures in surrounding landscapes resulted in less solitary and corbiculate bees in Austria, but more aboveground nesting species in South Africa. In both countries, associations between FRic of wild bees and flowering plants were positive both in organic and in conventional vineyards. We recommend the use of diverse cover crop seed mixtures to enhance plant flowering diversity in inter‐rows, to increase wild bee richness in viticultural landscapes.  相似文献   

6.
Since the 1970s, it has become increasingly difficult for U.S. alfalfa seed producers to maintain Megachile rotundata (F.) populations used for alfalfa, Medicago sativa L., pollination. In 1998, we monitored M. rotundata population dynamics and foraging behavior, as well as alfalfa bloom and pollination rates in two fields in eastern Oregon. Despite marked differences in bee management, establishment was very similar in the two fields (approximately 0.5 females per nesting cavity) and lagged peak bloom by approximately 2 wk. Pollination rates increased from 0-10% in the first 3 wk to 80-90% in week 4-5. By then, M. rotundata females had difficulty finding untripped (nonpollinated) flowers and visited large numbers of already tripped or not fully matured flowers. M. rotundata progeny mortality was very high (54-78%). Estimated seed yields were similar in both fields. We contend similar seed yields, and improved bee production, could be accomplished with smaller bee populations, better timed with alfalfa bloom.  相似文献   

7.
Satoyama is a traditional land management system in Japan that emphasizes the importance of a harmonious relationship between humans and their environment. It has been in a state of abandonment and destruction since the late 1960s. In 2000, the Japanese government initiated a new environment policy encouraging the use of Satoyama in biodiversity reservation areas. Before the initiation of active restoration works, an assessment of the potential of the Satoyama system is needed. To assess this potential, a study that focused on the foraging ecology of wild bees in a small abandoned Satoyama terraced paddy was carried out from June to October 2003. A total of 372 foraging bees belonging to 35 species in nine families was collected: two species of social bee ( Apis cerana and Bombus diversus ) and two of solitary bee ( Lasioglossum japonicum and Lasioglossum ohei ) dominated. The foraging activities of wild bees were highly influenced by the requirement of food for the colony and the active time of solitary bees. In the study, most wild bees showed a strong preference for abundant flowering plant species that produced a large number of flowers ( Achyranthes japonica and Polygonum thunbergii ). The results showed that an abandoned Satoyama system was an agricultural system that benefited pollinating bees. Careful and planned restoration practices to increase the diversity of foraging resources, microenvironment diversity and potential nesting areas for wild bees are needed to improve the ability of the Satoyama system to support more diverse and abundant wild bee populations.  相似文献   

8.
Capitol Reef National Park in central Utah, USA surrounds 22 managed fruit orchards started over a century ago by Mormon pioneers. Honey bees are imported for pollination, although the area in which the Park is embedded has over 700 species of native bees, many of which are potential orchard pollinators. We studied the visitation of native bees to apple, pear, apricot, and sweet cherry over 2 years. Thirty species of bees visited the flowers but, except for pear flowers, most were uncommon compared to honey bees. Evidence that honey bees prevented native bees from foraging on orchard crop flowers was equivocal: generally, honey bee and native bee visitation rates to the flowers were not negatively correlated, nor were native bee visitation rates positively correlated with distance of orchards from honey bee hives. Conversely, competition was tentatively suggested by much larger numbers of honey bees than natives on the flowers of apples, apricots and cherry; and by the large increase of native bees on pears, where honey bee numbers were low. At least one-third of the native bee species visiting the flowers are potential pollinators, including cavity-nesting species such as Osmia lignaria propinqua, currently managed for small orchard pollination in the US, plus several fossorial species, including one rosaceous flower specialist (Andrena milwaukiensis). We suggest that gradual withdrawal of honey bees from the Park would help conserve native bee populations without decreasing orchard crop productivity, and would serve as a demonstration of the commercial value of native pollinators.  相似文献   

9.
人工释放苜蓿切叶蜂的营巢行为观察   总被引:1,自引:0,他引:1  
苜蓿切叶蜂Megachile rotundata Fabricius是紫花苜蓿的理想授粉昆虫,国内外已广泛利用切叶蜂为紫花苜蓿授粉,因此,对切叶蜂的田间活动行为分析具有重要的实践指导意义。对苜蓿切叶蜂的田间营巢行为进行观测,结果表明:整个花期切叶蜂均十分活跃,放蜂的第4天开始适应环境,正常活动,7月8~22日,切叶蜂最为活跃,进入蜂巢的切叶蜂数最高时达426头/蜂巢,每日10:00~16:00为活动高峰。每日每块蜂巢的封孔数最多为14个,平均每个蜂室封闭巢孔的数量最多为185个。  相似文献   

10.
传粉蜂为作物生产和粮食安全提供重要的生态系统服务。随着农业经济的不断发展,土地利用强度加剧,大量自然或半自然生境已经转变为农业用地。景观均质化和集约化管理导致野生蜂多样性下降,从而威胁到农业可持续生产。本研究以北京市昌平区苹果园为对象,探究景观复杂度(半自然生境比例)、局地管理强度(地表开花植物多样性和土壤全氮)及其交互作用对传粉蜂多样性的影响。结果表明: 共捕获传粉蜂8642头,其中人工蜂5125头,野生蜂分属5科14属49种3517头。传粉蜂多样性对景观复杂度和局地管理强度响应的最优尺度在500 m。样点半径500 m范围内,总传粉蜂和野生蜂多度随周围半自然生境增加均呈显著上升趋势。景观复杂度与开花植物多样性的交互作用对总传粉蜂和野生蜂物种丰富度有显著影响。当景观复杂度较低时(≤29.9%),总传粉蜂和野生蜂物种丰富度与开花植物多样性呈显著正相关;而当景观复杂度较高时(>29.9%),总传粉蜂和野生蜂物种丰富度与开花植物多样性呈显著负相关。此外,人工蜂多度随果园内局地开花植物多样性和土壤全氮增加呈显著升高趋势。土壤全氮与开花植物多样性的交互作用对人工蜂多度有显著影响。当土壤全氮含量较低时(≤1.9 g·kg-1),人工蜂多度与开花植物多样性呈显著正相关;而当土壤全氮含量较高时(>1.9 g·kg-1),人工蜂多度与开花植物多样性呈显著负相关。农业景观中半自然生境比例的增加有利于提高野生蜂多度,而地表开花植物多样性可以促进传粉蜂多样性,但是受到景观尺度(半自然生境比例)和局地尺度(氮肥施用)的影响。因此,农业景观中野生蜂多样性的维持需要综合考虑多尺度因素来制定保护策略。尽可能保留更高比例的耕地仍然是生产的长期需求,而保持中等景观复杂度,增加地表开花植物多样性,减少氮肥施用量将是促进苹果园传粉蜂多样性的有效方式。  相似文献   

11.
Bees require distinct foraging and nesting resources to occur in close proximity. However, spatial and temporal patterns in the availability and quantity of these resources can be affected by disturbances like wildfire. The potential for spatial or temporal separation of foraging and nesting resources is of particular concern for solitary wood‐cavity‐nesting bees as they are central‐place, short‐distance foragers once they have established their nest. Often the importance of nesting resources for bees have been tested by sampling foraging bees as a proxy, and nesting bees have rarely been studied in a community context, particularly postdisturbance. We tested how wood‐cavity‐nesting bee species richness, nesting success, and nesting and floral resources varied across gradients of wildfire severity and time‐since‐burn. We sampled nesting bees via nesting boxes within four wildfires in southwest Montana, USA, using a space‐for‐time substitution chronosequence approach spanning 3–25 years postburn and including an unburned control. We found that bee nesting success and species richness declined with increasing time postburn, with a complete lack of successful bee nesting in unburned areas. Nesting and floral resources were highly variable across both burn severity and time‐since‐burn, yet generally did not have strong effects on nesting success. Our results together suggest that burned areas may provide important habitat for wood‐cavity‐nesting bees in this system. Given ongoing fire regime shifts as well as other threats facing wild bee communities, this work helps provide essential information necessary for the management and conservation of wood‐cavity‐nesting bees.  相似文献   

12.
Anthropogenic disturbances have caused pollinator decline by affecting the abundance and diversity of foraging plants. Anthropogenic disturbances are also thought to drive pollinator decline by reducing nest site availability, but the exact mechanisms by which human activities influence nest site availability are not currently well understood. In this study, we investigated nesting site preference of underground bee Andrena camellia Wu in two orchards. Principal component analysis of environmental factors (bulk density, penetration resistance, water content and temperature) indicated that A. camellia preferred loose, moist and low‐temperature habitats. The favored habitats were located at the bases of the foothills a long distance from human settlements. At the bases, favored nesting substrates decreased along the distance gradient, and nest densities of digger bees increased along the distance gradient. On the summit, however, nesting substrates were compacted, dried with high temperature regardless of distance from human settlements, and the nest densities were all low along the distance gradient. In summary, anthropogenic soil disturbances in the vicinity of human settlements threaten digger bees by altering soil characteristics. The conservation of the soil substrates is addressed in terms of its role in governing the population of digger bee A. camellia.  相似文献   

13.
沙地毛足蜂筑巢生物学研究   总被引:1,自引:0,他引:1  
【目的】调查毛乌素沙地的一种群居独栖性野生毛足蜂Dasypoda hirtipes Panzer的巢穴结构及其日活动规律。【方法】采用目测和拍照等方法对沙地毛足蜂的整个筑巢过程进行了连续观测;采用挖掘、测量方法对毛足蜂巢内结构进行了观测。【结果】2008和2009年共挖掘巢穴22个,巢口直径为6.32~10.35 mm,巢穴具有多分枝的支道,一般有4~16个分支道,主道的深度为84~112 cm,巢室分布在主道周围的支道里面,每个支道里面仅有1个巢室,巢室深度为22~54 cm。巢室内壁无蜡层,较光滑,巢室内的花粉球底部有3个均匀大小的用来支撑花粉球的突起。对雌性成蜂日活动行为的观察结果显示,雌性个体一天内采集粉蜜的次数在6~8次,最后一次一般不携带花粉归巢。【结论】在内蒙古毛乌素沙地,该蜂一年1代,日活动时间与菊科植物抱茎苦荬菜Ixeris sonchifolia花序中的单花期相对应,主要的蜜源植物为菊科植物和蒺藜属植物。  相似文献   

14.
Understanding pathogen transmission could illuminate new methods for disease prevention. A case in point is chalkbrood in the alfalfa leafcutting bee [Megachile rotundata (F.)]. Propagation of this solitary bee is severely hampered by chalkbrood, a larval disease caused by Ascosphaera aggregata (Ascomycota). Alfalfa leafcutting bees nest in existing cavities in wood or hollow reeds and overwinter as larvae. In the early summer, emerging adults frequently must chew through dead, diseased siblings that block their exit, becoming contaminated with chalkbrood spores in the process. When alfalfa leafcutting bees are used as a commercial pollinator, the cocoons are removed from nesting boards to reduce chalkbrood transmission, but the disease is still common. To determine if these removed cocoons (called loose cells) are an important source of disease transmission, they were disinfected with a fungicide before bees were incubated, and released in the field. Chalkbrood prevalence among the progeny of the treated bees was reduced up to 50% in one field trial, but not significantly when tested in an on-farm trial. Thus, substantial disease transmission still occurred when the loose cells were disinfected, and even when clean nesting materials were used. In conclusion, pathogen transmission must still be occurring from another source that has yet to be identified. Another possible source of transmission could arise from bees that emerge midsummer in populations with a high percent of multivoltinism, but dirty nesting boards and feral bees also may be minor sources of transmission.  相似文献   

15.
A significant concern in the commercial application of the alfalfa leafcutting bee, Megachile rotundata (F.) (Hymenoptera: Megachilidae), for pollination is synchronizing bee emergence and activity with peak crop bloom. Previous studies have demonstrated that the commercial spring incubation of this species can be successfully interrupted by low temperature incubation, thereby slowing development and giving producers flexibility in timing emergence to weather conditions or crop bloom. In this study, we demonstrate that the implementation of a fluctuating thermal regime, during which bees are given a daily one hour pulse of high temperature, markedly increases the "shelf-life" of individuals of this species. Although constant temperatures can be used to store bees for up to 1 wk with no decrease in survival, properly staged bees can be stored for up to 6 wk without a significant decrease in percentage of emergence. Hence, we expect fluctuating thermal regime protocols to become a valuable tool for M. rotundata managers, especially when timing nesting activity with peak bloom to maximize effectiveness.  相似文献   

16.
Synchronizing Megachile rotundata (F.) nesting activity with alfalfa bloom is essential for ensuring optimal pollination for alfalfa seed production. This is achieved by timing the initiation of spring bee incubation so that adults will emerge -2 wk before peak bloom. If weather conditions change so as to delay the bloom, bee managers will commonly expose the developing bees to a period of low-temperature incubation to slow their development. We have previously demonstrated survival during low-temperature incubation can be significantly increased by using a fluctuating thermal regime (FTR) where the bees receive a daily pulse at 20 degrees C. A FTR incubation protocol is composed of a number of different components, such as the base and pulse temperatures, and the duration and frequency of the pulse. In this investigation, the effect of the duration of the pulse (5-120 min) and the frequency of a pulse (twice daily to weekly) on the survival of developing M. rotundata was examined. A pulse as short as 5 min at 20 degrees C increased survival of the developing bees as compared with the constant 6 degrees C controls. Increasing the pulse duration induced a further increase in tolerance to 6 degrees C. As with the pulse duration, increasing the pulse frequency from once weekly to twice daily had a significant effect on improving the bees tolerance to low-temperature incubation. This investigation further strengthens the argument that a FTR protocol is superior to using a constant low-temperature exposure for interrupting the spring incubation of M. rotundata.  相似文献   

17.
Agricultural intensification leads to large-scale loss of habitats offering food and nesting sites for bees. This has resulted in a severe decline of wild bee diversity and abundance during the past decades. There is an urgent need for cost-effective conservation measures to mitigate this decline. We analysed the impact of five different high-quality habitats on species richness and abundance of wild bees in a complex landscape of north-western Switzerland at six sites. The five habitat types included 45 plots situated on eight organic farms and were composed of 16 low-input meadows, six low-input pastures, seven herbaceous strips adjacent to hedges, five sown flower strips and eleven organic cereal fields. All of them are financially subsidised by the Swiss agri-environmental scheme. Wild bees were sampled between the end of April and end of August 2014 by using trio-pan traps and complementary sweep netting on these five habitat types. On 45 plots we recorded 3973 bee specimens, belonging to 91 species, 16 of which are red listed, revealing a high bee species richness in the study area. Wild bee species richness and abundance were best explained by habitat type, number of flowering plants and site. A strong relationship of increasing number of flowering plants and bee species richness and abundance was found. Grassland habitats, especially low-input meadows, harboured the highest species richness and abundances. Organic cereal fields showed a potential to conserve bee species relevant to nature conservation (harbouring exclusively two red list species and four rare species). Ordination analysis of the bee communities showed a relative dissimilarity between the habitat types and indicates their complementary effects to benefit the diversity of wild bees. Our results demonstrate that a matrix of low-input habitats are needed to sustain rich assemblages of wild bees in agroecosystems.  相似文献   

18.
Samples of overwintering alfalfa leafcutting bee, Megachile rotundata (F.) (Hymenoptera: Megachilidae), cells were sent to the laboratory as loose cells or in nesting boards from bee managers in the United States and in Canada. X-radiographs of cells were used for determining cell contents. Cells containing live prepupae were incubated, and the sex of emerging adults was recorded daily. Cells from which no adult emerged were dissected to determine the developmental stage of dead bees and sex of dead pupae or adults. Bee cells incubated in commercial settings and placed in alfalfa fields by the same bee managers described above also were evaluated to determine adult emergence success. The proportion of live bees in wood nesting boards from the United States was much lower than the live proportion in polystyrene nesting boards from Canada and loose cells overwintered in the United States. For laboratory-incubated loose cells, survival and sex ratios of bees from Canadian sources were statistically higher than those of U.S. bees, but the onset and duration of emergence times were similar. Fewer bees survived in the commercial setting than in the laboratory. Prepupal mortality was significantly higher than pupal or adult mortality, but there was no significant difference between the sexes in the likelihood of survival during incubation. This study supports the commonly held belief that alfalfa leafcutting bees raised in Canada and then sold to the United States represent a more viable source of bees than most bees produced in the United States.  相似文献   

19.
Habitat restoration to promote wild pollinator populations is becoming increasingly common in agricultural lands. Yet, little is known about how wild bees, globally the most important wild pollinators, use resources in restored habitats. We compared bee use of native and exotic plants in two types of restored native plant hedgerows: mature hedgerows (>10 years from establishment) designed for natural enemy enhancement and new hedgerows (≤2 years from establishment) designed to enhance bee populations. Bees were collected from flowers using timed aerial netting and flowering plant cover was estimated by species using cover classes. At mature hedgerow sites, wild bee abundance, richness, and diversity were greater on native plants than exotic plants. At new sites, where native plants were small and had limited floral display, abundance of bees was greater on native plants than exotic plants; but, controlling for floral cover, there was no difference in bee diversity and richness between the two plant types. At both mature and new hedgerows, wild bees preferred to forage from native plants than exotic plants. Honey bees, which were from managed colonies, also preferred native plants at mature hedgerow sites but exhibited no preference at new sites. Our study shows that wild bees, and managed bees in some cases, prefer to forage on native plants in hedgerows over co‐occurring weedy, exotic plants. Semi‐quantitative ranking identified which native plants were most preferred. Hedgerow restoration with native plants may help enhance wild bee abundance and diversity, and maintain honey bee health, in agricultural areas.  相似文献   

20.
Livestock farming in the Eastern Cape, South Africa is a common land use practice that has affected the biodiversity of plants and animals in the region negatively. Indigenous populations of wild honey bee (Apis mellifera) colonies also may suffer. Recently, farmers in the Eastern Cape have been converting their farms to game reserves as ecotourism attractions and nature conservation lands. Consequently, the goal of this research was to determine if land use habits (livestock farming and conversion to game reserves) in the Eastern Cape affect honey bee colony population density and colony strength parameters. A series of indices were developed to compare the relative population densities of colonies in two or more areas by counting the number of foraging bees and number of bee lines established at feeding stations. Wild colonies on farms and reserves were located and sampled to determine land use effects on colony strength parameters including total area of comb in the colony, the area of comb containing stored honey, pollen, and brood, adult bee population, weight per bee, and the colony nest cavity volume ratio. When viewed collectively, the data indicated that land use practices have affected honey bee nesting dynamics in the Eastern Cape. Trends in the data suggested that colonies nesting on the reserves may occur in greater densities than those nesting on livestock farms, though they do not appear to be healthier. Hopefully, this work will be continued since honey bee conservation in areas where they are native is crucial to the health of agriculture and whole ecosystems globally.  相似文献   

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