共查询到20条相似文献，搜索用时 15 毫秒
1.
Climate change and biological invasions are two major global environmental challenges. Both may interact, e.g. via altered impact and distribution of invasive alien species. Even though invasive species play a key role for compromising the health of honey bees, the impact of climate change on the severity of such species is still unknown. The small hive beetle (SHB, Aethina tumida, Murray) is a parasite of honey bee colonies. It is endemic to sub‐Saharan Africa and has established populations on all continents except Antarctica. Since SHBs pupate in soil, pupation performance is governed foremost by two abiotic factors, soil temperature and moisture, which will be affected by climate change. Here, we investigated SHB invasion risk globally under current and future climate scenarios. We modelled survival and development time during pupation (=pupal performance) in response to soil temperature and soil moisture using published and novel experimental data. Presence data on SHB distribution were used for model validation. We then linked the model with global soil data in order to classify areas (resolution: 10 arcmin; i.e. 18.6 km at the equator) as unsuitable, marginal and suitable for SHB pupation performance. Under the current climate, the results show that many areas globally yet uninvaded are actually suitable, suggesting considerable SHB invasion risk. Future scenarios of global warming project a vehement increase in climatic suitability for SHB and corresponding potential for invasion, especially in the temperate regions of the Northern hemisphere, thereby creating demand for enhanced and adapted mitigation and management. Our analysis shows, for the first time, effects of global warming on a honey bee pest and will help areas at risk to prepare adequately. In conclusion, this is a clear case for global warming promoting biological invasion of a pest species with severe potential to harm important pollinator species globally. 相似文献
2.
Peter Neumann Jan Naef Karl Crailsheim Robin M. Crewe Christian W. W. Pirk 《Ecology and evolution》2015,5(23):5478-5486
Some parasites of social insects are able to exploit the exchange of food between nestmates via trophallaxis, because they are chemically disguised as nestmates. However, a few parasites succeed in trophallactic solicitation although they are attacked by workers. The underlying mechanisms are not well understood. The small hive beetle (=SHB), Aethina tumida, is such a parasite of honey bee, Apis mellifera, colonies and is able to induce trophallaxis. Here, we investigate whether SHB trophallactic solicitation is innate and affected by sex and experience. We quantified characteristics of the trophallactic solicitation in SHBs from laboratory‐reared individuals that were either bee‐naïve or had 5 days experience. The data clearly show that SHB trophallactic solicitation is innate and further suggest that it can be influenced by both experience and sex. Inexperienced SHB males begged more often than any of the other groups had longer breaks than their experienced counterparts and a longer soliciting duration than both experienced SHB males and females, suggesting that they start rather slowly and gain more from experience. Successful experienced females and males were not significantly different from each other in relation to successful trophallactic interactions, but had a significantly shorter soliciting duration compared to all other groups, except successful inexperienced females. Trophallactic solicitation success, feeding duration and begging duration were not significantly affected by either SHB sex or experience, supporting the notion that these behaviors are important for survival in host colonies. Overall, success seems to be governed by quality rather than quantity of interactions, thereby probably limiting both SHB energy investment and chance of injury (<1%). Trophallactic solicitation by SHBs is a singular example for an alternative strategy to exploit insect societies without requiring chemical disguise. Hit‐and‐run trophallaxis is an attractive test system to get an insight into trophallaxis in the social insects. 相似文献
3.
R. Andrew Hayes Brogan A. Amos Steven J. Rice Dalton K. Baker Diana M. Leemon 《Entomologia Experimentalis et Applicata》2019,167(9):784-793
The small hive beetle, Aethina tumida Murray (Coleoptera: Nitidulidae), is a significant pest of managed honeybees in the USA and eastern Australia. The beetle damages hives by feeding on hive products and leaving behind fermented wastes. The beetle is consistently associated with the yeast Kodamaea ohmeri (Etchells & Bell) Yamada et al. (Saccharomycetales: Metschnikowiaceae), and this yeast is the presumed agent of the fermentation. Previous work has noted that the small hive beetle is attracted to volatiles from hive products and those of the yeast K. ohmeri. In this study, we investigated how the volatile compounds from the fermenting hive products change depending upon the source of the hive material and also how these volatiles change through time. We used gas chromatography–mass spectrometry and choice‐test behavioural assays to investigate these changes using products sampled from apiaries across the established range of the beetle in eastern Australia. The starting hive products significantly affected the volatile composition of fermenting hive products, and this composition varied throughout time. We found 61.7% dissimilarity between attractive and non‐attractive fermenting hive products, and identified individual compounds that characterise each of these groups. Eleven of these individual compounds were then assessed for attractiveness, as well as testing a synthetic blend in the laboratory. In the laboratory bioassay, 82.1 ± 0.02% of beetles were trapped in blend traps. These results have strong implications for the development of an out‐of‐hive attractant trap to assist in the management of this invasive pest. 相似文献
4.
Peter C. Gregg George S. Henderson Alice P. Del Socorro Kris Le Mottee Craig Birchall 《Austral ecology》2016,41(7):819-828
We investigated potential primary hosts for Helicoverpa punctigera, a polyphagous lepidopteran pest which affects many crops, but also has many native hosts in non‐cropping regions of inland Australia. The most common hosts are Asteraceae and Fabaceae, but there is little information on the relative importance of different species in these families for the population dynamics of H. punctigera in the inland. We tested three common hosts, one legume (Cullen cinereum) and two daisies, Rhodanthe floribunda and Polycalymma stuartii, for their suitability for survival and growth of early instar larvae. Survival was high on the flowers of all three species, and on the leaves of C. cinereum and R. floribunda, but low on leaves of P. stuartii. There were significant differences in growth rates, measured by head widths, in the order of C. cinereum > R. floribunda > P. stuartii, and flowers > leaves. They were strongly correlated with nitrogen content, measured by fresh weight. Field surveys of larval populations in western Queensland indicated that two legume species, C. cinereum and Cullen pallidum, were widely utilized and supported many larvae. Daisies were generally less widely used and/or had lower numbers of larvae. When C. cinereum or C. pallidum was found near daisies, the legume had more larvae if both the daisy and the legume were flowering, but this was reversed if only the daisy was flowering. The seasonality and habitats of the daisies and legumes are different. C. cinereum and C. pallidum (a new host record for H. punctigera) may be primary hosts of H. punctigera in inland Australia and key hosts for maintaining populations in flood plains. However the areas occupied by daisies can be more extensive depending on rainfall, and some species may be critical in generating outbreaks that affect cropping areas in southeast Australia. 相似文献
5.
Reisla Oliveira Christiane R. Pereira Ana Laura A. F. D. Pimentel Clemens Schlindwein 《Ethology : formerly Zeitschrift fur Tierpsychologie》2016,122(8):632-639
Territorial males may adopt a mating tactic that yields greater reproductive success but that at the same time increases the risk of predation. Plasticity in reproductive behavior can reflect a balance between sexual selection and natural selection. In this study, we sought to verify the effect of predation risk on territorial behavior of males of the solitary bee Ptilothrix fructifera (Apidae). Males of the species employ alternative mating tactics and can be territorial in defense of larval food sources. By manipulating predator models in the field, we tested whether (1) males avoid perch flowers containing predator models; (2) males alternate between mating tactics when their territory is associated with a predation risk; and (3) female foraging on flowers in a territory is altered in the presence of a predator model. We measured the responses of males and females in flowers containing and not containing a model of a spider or a stuffed bird. The results show that territorial males of P. fructifera alter their territorial behavior when faced with a high risk of predation. They do not abandon their territory or change to a non‐territorial mating tactic, but instead change the use of their territory, avoiding flowers containing predator models or perching on other flowers when the previous flower presented a potential predation risk. Female P. fructifera decreases the frequency of their visits to flowers and the length of time spent there in the presence of a spider model. In short, in the face of predation risk, females and males alter their behaviors at the cost of less efficient foraging and searching for partners, respectively. 相似文献
6.
Erica Juel Ahrenfeldt Lene Sigsgaard Lise Hansted Anders Christian Jensen Torben Bo Toldam‐Andersen 《Entomologia Experimentalis et Applicata》2019,167(8):763-773
Nectar is a vital source of energy for bees and other pollinators and pollen represents the only source of protein in the diet of bees. Nectar and pollen quality and quantity can therefore affect foraging choices. Strawberry, Fragaria × ananassa (Rosaceae), is a flowering crop that requires insect pollination for the berries to develop optimally. The solitary red mason bee, Osmia bicornis L. (Hymenoptera: Megachilidae), occurs naturally but like the eusocial western honeybee, Apis mellifera mellifera L. (Hymenoptera: Apidae), it is also a commercially reared pollinator used in strawberry production. We hypothesized that strawberry nectar and pollen quality would affect the foraging choice of these two types of bees. In this study nectar and pollen quality is represented by various levels of sugar and protein content, respectively, as well as the number of open strawberry flowers in the experimental field, would affect the foraging choice of these two types of bees. Consistent with previous studies, we found significant and major differences between strawberry varieties in proportions of sucrose in the nectar sugar and in pollen viability – a proxy for pollen protein content. All measured parameters had a significant effect on red mason bee visitation frequency. Contrary to expectations, honeybee foraging behavior was only affected by the number of open flowers and not by any of the quality parameters measured. Our findings indicate that red mason bees were capable of assessing nectar and pollen quality and prioritize accordingly. The pattern observed indicates that individual red mason bees changed foraging focus between strawberry varieties depending on whether nectar or pollen was collected. Our results suggest that targeted breeding of varieties toward high levels of nectar sugar and sucrose concentrations and high pollen protein content may increase pollination success from red mason bees and possibly other solitary bees. 相似文献
7.
James Scott MacIvor Adriano N. Roberto Darwin S. Sodhi Thomas M. Onuferko Marc W. Cadotte 《Ecology and evolution》2017,7(20):8456-8462
In eastern North America, the field milkweed, Asclepias syriaca L. (Asclepiadaceae), is used in planting schemes to promote biodiversity conservation for numerous insects including the endangered monarch butterfly, Danaus plexippus (Linnaeus) (Nymphalidae). Less is known about its pollinators, and especially in urban habitats where it is planted often despite being under increasing pressure from invasive plant species, such as the related milkweed, the dog‐strangling vine (DSV), Vincetoxicum rossicum (Kleopow) Barbar. (Asclepiadaceae). During the A. syriaca flowering period in July 2016, we surveyed bees in open habitats along a DSV invasion gradient and inspected 433 individuals of 25 bee species in 12 genera for pollinia: these were affixed to bees that visited A. syriaca for nectar and contain pollen packets that are vectored (e.g., transferred) between flowers. Of all bees sampled, pollinia were found only on the nonindigenous honeybee, Apis mellifera (43% of all bees identified), as well as one individual bumblebee, Bombus impatiens Cresson. Pollinia were recorded from 45.2% of all honeybees collected. We found no relationship between biomass of DSV and biomass of A. syriaca per site. There was a significant positive correlation between A. syriaca biomass and the number of pollinia, and the proportion vectored. No relationship with DSV biomass was detected for the number of pollinia collected by bees but the proportion of vectored pollinia declined with increasing DSV biomass. Although we find no evidence of DSV flowers attracting potential pollinators away from A. syriaca and other flowering plants, the impacts on native plant–pollinator mutualisms relate to its ability to outcompete native plants. As wild bees do not appear to visit DSV flowers, it could be altering the landscape to one which honeybees are more tolerant than native wild bees. 相似文献
8.
Bees are considered the most important plant pollinators in many ecosystems, yet little is known about pollination of native plants by bees in many Australian ecosystems including the alpine region. Here we consider bee pollination in this region by constructing a bee visitation network and investigating the degree of specialism and network ‘nestedness’, which are related to the robustness of the network to perturbations. Bees and flowers were collected and observed from 10 sites across the Bogong High Plains/Mt Hotham region in Victoria. Low nestedness and a low degree of specialism were detected, consistent with patterns in other alpine regions. Twenty‐one native and one non‐indigenous bee species were observed visiting 46 of the 67 flower species recorded. The introduced Apis mellifera had a large floral overlap with native bees, which may reduce fecundity of native bees through competition. The introduced plant, Hypochaeris radicata (Asteraceae), had the largest and most sustained coverage of any flower and had the most visitations and bee species of any flower. The network developed in this study is a first step in understanding pollination patterns in the alpine/subalpine region and serves as a baseline for future comparisons. 相似文献
9.
Host plant resistance can effectively manage Russian wheat aphid (Diuraphis noxia) Kurdjumov (Homoptera: Aphididae) in areas where it is an economically important pest of wheat. However, biotypes of D. noxia virulent on wheat containing resistance gene Dn4 have been reported in both the United States and South Africa. Thirty wheat genotypes, including susceptible Yuma, resistant CItr2401, as well as 25 genotypes containing Dn4 and three genotypes containing Dny were planted under greenhouse conditions in Bethlehem, South Africa, and screened with D. noxia biotype RWASA3. RWASA3 caused susceptible damage symptoms in MTRWA92‐145, Ankor, Halt, Bond CL, 18FAWWON‐SA 262, Prowers99, 18FAWWON‐SA 264, Hatcher, Yumar, Corwa and Thunder CL all reported to contain the Dn4 resistance gene. Genotypes PI586956, Stanton and 18FAWWON‐SA 257, containing the Dny‐resistance gene were susceptible to RWASA3. Similarly, coinciding development of virulence to resistance genes Dn4 and Dny was reported in the United States. However, in this study, 13 Dn4‐containing genotypes showed moderate resistance when screened with RWASA3 alluding to a more complex biotype‐gene‐interaction. These findings could indicate that Dn4 and Dny may be related and possibly share a similar or common resistance factor. Further studies will be aimed at explaining these results investigating the possibility of an allelic cluster or series for Dn4, possibly including Dny. 相似文献
10.
11.
Alternaria fungi are important plant pathogens. Here, we identified three species new to the Japanese mycoflora: Alternaria celosiae, Alternaria crassa and Alternaria petroselini. We proposed a new name for A. celosiae (E.G. Simmons & Holcomb) Lawrence, Park & Pryor, a later homonym of A. celosiae (Tassi) O. S?vul. To characterize these and a fourth morphological taxon, Alternaria alstroemeriae, which was recently added to Japan's mycoflora, an integrated species concept was tested. We determined the host range of each isolate using inoculation tests and analysed its phylogenetic position using sequences of the internal transcribed spacer rDNA. The pathogenicity of our A. alstroemeriae isolate was strictly limited to Alstroemeria sp. (Alstroemeriaceae), but the species was phylogenetically indistinguishable from other small‐spored Alternaria. Alternaria celosiae on Celosia argentea var. plumosa (Amaranthaceae) was also pathogenic to Amaranthus tricolor, to Alternanthera paronychioides and weakly to Gomphrena globosa (all Amaranthaceae) and formed a clade with the former Nimbya celosiae. Alternaria crassa on Datura stramonium (Solanaceae) was also pathogenic to Brugmansia × candida and Capsicum annuum in Solanaceae, but not to other confamilial plants; phylogenetically it belonged to a clade of large‐spored species with filamentous beaks. Morphological similarity, phylogenetic relationship and experimental host range suggested that A. crassa, Alternaria capsici and Alternaria daturicola were conspecific. Alternaria petroselini on Petroselinum crispum (Apiaceae) was pathogenic to five species in the tribe Apieae as well as representatives of Bupleureae, Coriandreae, Seliaeae and Scandiceae in Apiaceae. Both phylogeny and morphology suggested conspecificity between A. petroselini and Alternaria selini. 相似文献
12.
Dennis Baulechner Nina I. Becker Jorge A. Encarnação 《Journal of Zoological Systematics and Evolutionary Research》2013,51(3):203-212
Host specificity in parasites can be explained by spatial isolation from other potential hosts or by specialization and speciation of specific parasite species. The first assertion is based on allopatric speciation, the latter on differential lifetime reproductive success on different available hosts. We investigated the host specificity and cophylogenetic histories of four sympatric European bat species of the genus Myotis and their ectoparasitic wing mites of the genus Spinturnix. We sampled >40 parasite specimens from each bat species and reconstructed their phylogenetic COI trees to assess host specificity. To test for cospeciation, we compared host and parasite trees for congruencies in tree topologies. Corresponding divergence events in host and parasite trees were dated using the molecular clock approach. We found two species of wing mites to be host specific and one species to occur on two unrelated hosts. Host specificity cannot be explained by isolation of host species, because we found individual parasites on other species than their native hosts. Furthermore, we found no evidence for cospeciation, but for one host switch and one sorting event. Host‐specific wing mites were several million years younger than their hosts. Speciation of hosts did not cause speciation in their respective parasites, but we found that diversification of recent host lineages coincided with a lineage split in some parasites. 相似文献
13.
José L. Tapia Benjamin Nogueda Torres Govinda S. Visvesvara 《The Journal of eukaryotic microbiology》2013,60(5):448-454
Although Balamuthia mandrillaris was identified more than two decades ago as an agent of fatal granulomatous encephalitis in humans and other animals, little is known about its ecological niche, biological behavior in the environment, food preferences and predators, if any. When infecting humans or other animals, Balamuthia feeds on tissues; and in vitro culture, it feeds on mammalian cells (monkey kidney cells, human lung fibroblasts, and human microvascular endothelial cells). According to recent reports, it is believed that Balamuthia feeds on small amebae, for example, Acanthamoeba that are present in its ecological niche. To test this hypothesis, we associated Balamuthia on a one‐on‐one basis with selected protozoa and algae. We videotaped the behavior of Balamuthia in the presence of a potential prey, its ability to hunt and attack its food, and the time required to eat and cause damage to the target cell by direct contact. We found that B. mandrillaris ingested trophozoites of Naegleria fowleri, Naegleria gruberi, Acanthamoeba spp., Trypanosoma cruzi epimastigotes, Toxoplasma gondii tachyzoites, and Giardia. However, it did not feed on Acanthamoeba cysts or algae. Balamuthia caused cytolysis of T. cruzi epimastigotes and T. gondii tachyzoites by direct contact. Balamuthia trophozoites and cysts were, however, eaten by Paramecium sp. 相似文献
14.
The occurrence and extent of multiple paternity is an important component of variation in plant mating dynamics. However, links between pollinator activity and multiple paternity are generally lacking, especially for plant species that attract functionally diverse floral visitors. In this study, we separated the influence of two functionally distinct floral visitors (hawkmoths and solitary bees) and characterized their impacts on multiple paternity in a self‐incompatible, annual forb, Oenothera harringtonii (Onagraceae). We also situated pollinator‐mediated effects in a spatial context by linking variation in multiple paternity to variation in plant spatial isolation. We documented pronounced differences in the number of paternal sires as function of pollinator identity: on average, the primary pollinator (hawkmoths) facilitated mating with nearly twice as many pollen donors relative to the secondary pollinator (solitary bees). This effect was consistent for both isolated and nonisolated individuals, but spatial isolation imposed pronounced reductions on multiple paternity regardless of pollinator identity. Considering that pollinator abundance and pollen dispersal distance did not vary significantly with pollinator identity, we attribute variation in realized mating dynamics primarily to differences in pollinator morphology and behaviour as opposed to pollinator abundance or mating incompatibility arising from underlying spatial genetic structure. Our findings demonstrate that functionally distinct pollinators can have strongly divergent effects on polyandry in plants and further suggest that both pollinator identity and spatial heterogeneity have important roles in plant mating dynamics. 相似文献
15.
Joshua G. Lynton‐Jenkins Aisha C. Bründl Maxime Cauchoix La A. Lejeune Louis Sall Alice C. Thiney Andrew F. Russell Alexis S. Chaine Camille Bonneaud 《Ecology and evolution》2020,10(12):6097-6111
Understanding the ecology and evolution of parasites is contingent on identifying the selection pressures they face across their infection landscape. Such a task is made challenging by the fact that these pressures will likely vary across time and space, as a result of seasonal and geographical differences in host susceptibility or transmission opportunities. Avian haemosporidian blood parasites are capable of infecting multiple co‐occurring hosts within their ranges, yet whether their distribution across time and space varies similarly in their different host species remains unclear. Here, we applied a new PCR method to detect avian haemosporidia (genera Haemoproteus, Leucocytozoon, and Plasmodium) and to determine parasite prevalence in two closely related and co‐occurring host species, blue tits (Cyanistes caeruleus, N = 529) and great tits (Parus major, N = 443). Our samples were collected between autumn and spring, along an elevational gradient in the French Pyrenees and over a three‐year period. Most parasites were found to infect both host species, and while these generalist parasites displayed similar elevational patterns of prevalence in the two host species, this was not always the case for seasonal prevalence patterns. For example, Leucocytozoon group A parasites showed inverse seasonal prevalence when comparing between the two host species, being highest in winter and spring in blue tits but higher in autumn in great tits. While Plasmodium relictum prevalence was overall lower in spring relative to winter or autumn in both species, spring prevalence was also lower in blue tits than in great tits. Together, these results reveal how generalist parasites can exhibit host‐specific epidemiology, which is likely to complicate predictions of host–parasite co‐evolution. 相似文献
16.
Koro Gotoh Takayuki Masaki Seiichi Chiba Hisae Ando Kansuke Fujiwara Takanobu Shimasaki Kimihiko Mitsutomi Isao Katsuragi Tetsuya Kakuma Toshiie Sakata Hironobu Yoshimatsu 《Journal of neurochemistry》2013,125(4):588-598
Brain‐derived neurotrophic factor (BDNF), corticotropin‐releasing factor (CRF), and hypothalamic neuronal histamine are anorexigenic substances within the hypothalamus. This study examined the interactions among BDNF, CRF, and histamine during the regulation of feeding behavior in rodents. Food intake was measured after treatment with BDNF, α‐fluoromethyl histidine (FMH; a specific suicide inhibitor of histidine decarboxylase that depletes hypothalamic neuronal histamine), or CRF antagonist. We measured food intake in wild‐type mice and mice with targeted disruption of the histamine H1 receptor (H1KO mice) after central BDNF infusion. Furthermore, we investigated CRF content and histamine turnover in the hypothalamus after BDNF treatment, and conversely, BDNF content in the hypothalamus after histamine treatment. We used immunohistochemical staining for histamine H1 receptors (H1‐R) in BDNF neurons. BDNF‐induced feeding suppression was partially attenuated in rats pre‐treated with FMH or a CRF antagonist, and in H1KO mice. BDNF treatment increased CRF content and histamine turnover in the hypothalamus. Histamine increased BDNF content in the hypothalamus. Immunohistochemical analysis revealed that H1‐Rs were expressed on BDNF neurons in the ventromedial nucleus of the hypothalamus. These results indicate that CRF and hypothalamic neuronal histamine mediate the suppressive effects of BDNF on feeding behavior and body weight. 相似文献
17.
Y. Fukano H. Doi C. E. Thomas M. Takata S. Koyama T. Satoh 《Journal of evolutionary biology》2016,29(4):757-765
Host range expansion of herbivorous insects is a key event in ecological speciation and insect pest management. However, the mechanistic processes are relatively unknown because it is difficult to observe the ongoing host range expansion in natural population. In this study, we focused on the ongoing host range expansion in introduced populations of the ragweed leaf beetle, Ophraella communa, to estimate the evolutionary process of host plant range expansion of a herbivorous insect. In the native range of North America, O. communa does not utilize Ambrosia trifida, as a host plant, but this plant is extensively utilized in the beetle's introduced range. Larval performance and adult preference experiments demonstrated that native O. communa beetles show better survival on host plant individuals from introduced plant populations than those from native plant populations and they also oviposit on the introduced plant, but not on the native plant. Introduced O. communa beetles showed significantly higher performance on and preference for both introduced and native A. trifida plants, when compared with native O. communa. These results indicate the contemporary evolution of host plant range expansion of introduced O. communa and suggest that the evolutionary change of both the host plant and the herbivorous insect involved in the host range expansion. 相似文献
18.
Daniel T. Nevin Christopher J. Morgan David Y. Graham Robert M. Genta 《Helicobacter》2014,19(5):323-329
19.
Thomas Henneresse Aurlien Kaiser Renate A. Wesselingh Daniel Tyteca 《Nordic Journal of Botany》2019,37(4)
Plant density varies naturally, from isolated plants to clumped individuals, and this can influence pollinator foraging behaviour and plant reproductive success. In addition, the effect of conspecific density on reproduction may depend on the pollination system, and deceptive species differ from rewarding ones in this regard, a high density being often associated with low fruit set in deceptive plants. In our study, we aimed to determine how local conspecific density and floral display size (i.e. number of flowers per plant) affect fruit set in a deceptive orchid (Orchis militaris) through changes in pollinator visitation. We measured fruit set in a natural population and recorded pollinator abundance and foraging behaviour within plots of different O. militaris densities. Detailed data were recorded for the most abundant potential pollinators of O. militaris, i.e. solitary bees. Floral display size was negatively correlated to fruit set in medium‐density plots, but uncorrelated in low‐ and high‐density plots. Plot density had no effect on solitary bee abundance and visitation, which may be due to low pollinator abundance within the study site. The proportion of visited flowers per inflorescence was negatively influenced by floral display size, which is in line with previous studies. In addition, solitary bees spent decreasing time in successive flowers within an inflorescence, and the time spent per flower was negatively affected by ambient temperature. Our results suggest that pollinator behaviour during visitation is poorly linked to pollen deposition and reproductive success in O. militaris. 相似文献
20.
Synnøve Botnen Unni Vik Tor Carlsen Pernille B. Eidesen Marie L. Davey Håvard Kauserud 《Molecular ecology》2014,23(4):975-985
In High Arctic ecosystems, plant growth and reproduction are limited by low soil moisture and nutrient availability, low soil and air temperatures, and a short growing season. Mycorrhizal associations facilitate plant nutrient acquisition and water uptake and may therefore be particularly ecologically important in nutrition‐poor and dry environments, such as parts of the Arctic. Similarly, endophytic root associates are thought to play a protective role, increasing plants' stress tolerance, and likely have an important ecosystem function. Despite the importance of these root‐associated fungi, little is known about their host specificity in the Arctic. We investigated the host specificity of root‐associated fungi in the common, widely distributed arctic plant species Bistorta vivipara, Salix polaris and Dryas octopetala in the High Arctic archipelago Svalbard. High‐throughput sequencing of the internal transcribed spacer 1 (ITS1) amplified from whole root systems generated no evidence of host specificity and no spatial autocorrelation within two 3 m × 3 m sample plots. The lack of spatial structure at small spatial scales indicates that Common Mycelial Networks (CMNs) are rare in marginal arctic environments. Moreover, no significant differences in fungal OTU richness were observed across the three plant species, although their root system characteristics (size, biomass) differed considerably. Reasons for lack of host specificity could be that association with generalist fungi may allow arctic plants to more rapidly and easily colonize newly available habitats, and it may be favourable to establish symbiotic relationships with fungi possessing different physiological attributes. 相似文献