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51.
Do exotic bumblebees and honeybees compete with native flower-visiting insects in Tasmania? 总被引:2,自引:0,他引:2
Honeybees, Apis mellifera, have been introduced by man throughout the globe. More recently, other bee species including various bumblebees (Bombus spp.) have been introduced to several new regions. Here we examine the impacts of honeybees and the bumblebee, Bombus terrestris, on native flower-visiting insects in Tasmania. To assess whether native insects have lower abundance or are excluded in areas that have been colonised by exotic bees, we quantified the abundance, diversity and floral preferences of flower-visiting insects at sites where bumblebees and honeybees were present, and compared them to sites where they were absent. This was achieved by hand searches at 67 sites, and by deploying sticky traps at 122 sites. Honeybees were by far the most abundant bee species overall, and dominated the bee fauna at most sites. There was considerable niche overlap between honeybees, bumblebees and native bees in terms of the flowers that they visited. Sites where bumblebees were established had similar species richness, diversity and abundance of native flower-visiting insects compared to sites where bumblebees were absent. In contrast, native bees were more than three times more abundant at the few sites where honeybees were absent, compared to those where they were present. Our results are suggestive of competition between honeybees and native bees, but exclusion experiments are needed to provide a definitive test. 相似文献
52.
Bumblebees and honeybees deposit short-lived scent marks on flowers that they visit when foraging. Conspecifics use these marks to distinguish those flowers that have recently been emptied and, so, avoid them. The aim of this study was to assess how widespread this behavior is. Evidence for direct detection of reward levels was found in two bee species: Agapostemon nasutus was able to detect directly pollen availability in flowers with exposed anthers, while Apis mellifera appeared to be able to detect nectar levels of tubular flowers. A third species, Trigona fulviventris, avoided flowers that had recently been visited by conspecifies, regardless of reward levels, probably by using scent marks. Three further bee/flower systems were examined in which there was no detectable discrimination among flowers. We argue that bees probably rely on direct detection of rewards where this is allowed by the structure of the flower and on scent marks when feeding on flowers where the rewards are hidden. However, discrimination does not always occur. We suggest that discrimination may not always make economic sense; when visiting flowers with a low handling time, or flowers that are scarce, it may be more efficient to visit every flower that is encountered. 相似文献
53.
54.
Molecular tools and bumble bees: revealing hidden details of ecology and evolution in a model system
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S. Hollis Woodard Jeffrey D. Lozier David Goulson Paul H. Williams James P. Strange Shalene Jha 《Molecular ecology》2015,24(12):2916-2936
Bumble bees are a longstanding model system for studies on behaviour, ecology and evolution, due to their well‐studied social lifestyle, invaluable role as wild and managed pollinators, and ubiquity and diversity across temperate ecosystems. Yet despite their importance, many aspects of bumble bee biology have remained enigmatic until the rise of the genetic and, more recently, genomic eras. Here, we review and synthesize new insights into the ecology, evolution and behaviour of bumble bees that have been gained using modern genetic and genomic techniques. Special emphasis is placed on four areas of bumble bee biology: the evolution of eusociality in this group, population‐level processes, large‐scale evolutionary relationships and patterns, and immunity and resistance to pesticides. We close with a prospective on the future of bumble bee genomics research, as this rapidly advancing field has the potential to further revolutionize our understanding of bumble bees, particularly in regard to adaptation and resilience. Worldwide, many bumble bee populations are in decline. As such, throughout the review, connections are drawn between new molecular insights into bumble bees and our understanding of the causal factors involved in their decline. Ongoing and potential applications to bumble bee management and conservation are also included to demonstrate how genetics‐ and genomics‐enabled research aids in the preservation of this threatened group. 相似文献
55.
The causes of declines in bees and other pollinators remains an on-going debate. While recent attention has focussed upon pesticides, other environmental pollutants have largely been ignored. Aluminium is the most significant environmental contaminant of recent times and we speculated that it could be a factor in pollinator decline. Herein we have measured the content of aluminium in bumblebee pupae taken from naturally foraging colonies in the UK. Individual pupae were acid-digested in a microwave oven and their aluminium content determined using transversely heated graphite furnace atomic absorption spectrometry. Pupae were heavily contaminated with aluminium giving values between 13.4 and 193.4 μg/g dry wt. and a mean (SD) value of 51.0 (33.0) μg/g dry wt. for the 72 pupae tested. Mean aluminium content was shown to be a significant negative predictor of average pupal weight in colonies. While no other statistically significant relationships were found relating aluminium to bee or colony health, the actual content of aluminium in pupae are extremely high and demonstrate significant exposure to aluminium. Bees rely heavily on cognitive function and aluminium is a known neurotoxin with links, for example, to Alzheimer’s disease in humans. The significant contamination of bumblebee pupae by aluminium raises the intriguing spectre of cognitive dysfunction playing a role in their population decline. 相似文献
56.
Chapman Jason W.; Williams Trevor; Escribano Ana; Caballero Primitivo; Cave Ronald D.; Goulson Dave 《Behavioral ecology》1999,10(3):298-303
We investigated the consequences of cannibalism for some correlatesof
fitness in the fall armyworm, Spodoptera frugiperda (Lepidoptera:
Noctuidae).The benefits gained by cannibals were ascertained by comparing
survival,development rate, and pupal weight of larvae that had the
opportunityto cannibalize with those that did not, at two levels of food
availability.Larvae in the cannibalism treatments were provided with a
conspecificone instar younger than themselves on five dates throughoutlarval
development. Cannibalism was frequent; given the opportunityall larvae
predated at least one younger conspecific. The frequencyof cannibalism was
not affected by the sex of the cannibal orby the availability of alternative
food. However, cannibalssuffered a significant reduction in survival at both
high andlow food availability. Furthermore, cannibals had a lower pupal
weightin the high food treatment and a reduced development rate inthe low
food treatment. The only detectable fitness benefitassociated with
cannibalism was a positive correlation betweenthe number of victims consumed
and development rate under conditionsof low food availability. On balance,
cannibalism appears tobe costly; alternative explanations for its occurrence
in thisspecies are discussed. 相似文献
57.
Effects of phenotypic plasticity on pathogen transmission in the field in a Lepidoptera-NPV system 总被引:1,自引:1,他引:0
A. F. Reeson K. Wilson J. S. Cory P. Hankard J. M. Weeks D. Goulson R. S. Hails 《Oecologia》2000,124(3):373-380
In models of insect–pathogen interactions, the transmission parameter (ν) is the term that describes the efficiency with which
pathogens are transmitted between hosts. There are two components to the transmission parameter, namely the rate at which
the host encounters pathogens (contact rate) and the rate at which contact between host and pathogen results in infection
(host susceptibility). Here it is shown that in larvae of Spodoptera exempta (Lepidoptera: Noctuidae), in which rearing density triggers the expression of one of two alternative phenotypes, the high-density
morph is associated with an increase in larval activity. This response is likely to result in an increase in the contact rate
between hosts and pathogens. Rearing density is also known to affect susceptibility of S. exempta to pathogens, with the high-density morph showing increased resistance to a baculovirus. In order to determine whether density-dependent
differences observed in the laboratory might affect transmission in the wild, a field trial was carried out to estimate the
transmission parameter for S. exempta and its nuclear polyhedrosis virus (NPV). The transmission parameter was found to be significantly higher among larvae reared
in isolation than among those reared in crowds. Models of insect–pathogen interactions, in which the transmission parameter
is assumed to be constant, will therefore not fully describe the S. exempta-NPV system. The finding that crowding can influence transmission in this way has major implications for both the long-term
population dynamics and the invasion dynamics of insect–pathogen systems.
Received: 14 June 1999 / Accepted: 22 March 2000 相似文献
58.
An economic model of the limits to foraging range in central place foragers with numerical solutions for bumblebees 总被引:11,自引:0,他引:11
1. A model is described that evaluates the maximum economic foraging range in central place foragers by using optimality criteria to discriminate between foraging sites at different distances from the forager's central place. 2. The basic model can be varied to suit foragers that optimise either their rate of net energy uptake or their foraging efficiency. 3. The model requires specification of the time and energy budgets of travel and foraging, and of the rewards obtainable at potential foraging sites. 4. The specific case of bumblebees, whose foraging ranges are poorly known, is considered. 5. Numerical solutions of the model for parameter values that represent bumblebees and their forage predict economic foraging ranges exceeding several kilometres. The model demonstrates that economics alone can explain extensive flight ranges in bees. 相似文献
59.
With many plant–pollinator interactions undergoing change as species’ distributions shift, we require a better understanding of how the addition of new interacting partners can affect plant reproduction. One such group of floral visitors, nectar robbers, can deplete plants of nectar rewards without contributing to pollination. The addition of nectar robbing to the floral visitor assemblage could therefore have costs to the plant´s reproductive output. We focus on a recent plant colonist, Digitalis purpurea, a plant that in its native range is rarely robbed, but experiences intense nectar robbing in areas it has been introduced to. Here, we test the costs to reproduction following experimental nectar robbing. To identify any changes in the behavior of the principal pollinators in response to nectar robbing, we measured visitation rates, visit duration, proportion of flowers visited, and rate of rejection of inflorescences. To find the effects of robbing on fitness, we used proxies for female and male components of reproductive output, by measuring the seeds produced per fruit and the pollen export, respectively. Nectar robbing significantly reduced the rate of visitation and lengths of visits by bumblebees. Additionally, bumblebees visited a lower proportion of flowers on an inflorescence that had robbed flowers. We found that flowers in the robbed treatment produced significantly fewer seeds per fruit on average but did not export fewer pollen grains. Our finding that robbing leads to reduced seed production could be due to fewer and shorter visits to flowers leading to less effective pollination. We discuss the potential consequences of new pollinator environments, such as exposure to nectar robbing, for plant reproduction. 相似文献
60.