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1.
    
Adults of the invasive goldspotted oak borer, Agrilus auroguttatus Schaeffer (Coleoptera: Buprestidae), consumed foliar weight in no‐choice feeding tests of, in descending order, California black oak Quercus kelloggii Newb., Engelmann oak, Quercus engelmannii Greene, coast live oak, Quercus agrifolia Née, and canyon live oak, Quercus chrysolepis Liebm. (Fagaceae). Furthermore, significantly more foliar area was consumed of Q. kelloggii than of Q. chrysolepis. In dual‐choice feeding tests with isolated leaf disks, A. auroguttatus consumed significantly more foliar weight and area of Q. kelloggii relative to the other three oak species, and more foliar weight of Q. agrifolia than of Q. chrysolepis. In dual‐choice feeding tests with leaves on small branches, A. auroguttatus consumed more foliar weight of Q. kelloggii than of Q. engelmannii and Q. agrifolia. Thus, multiple experiments suggested that adults of A. auroguttatus preferred the foliage of Q. kelloggii over that of the other three oak species, and among the other three species they did not appear to have a strong feeding preference. Factor analysis reduced the quantities of 13 foliar nutrients into two new variables (factor 1 and factor 2). Factor 1 was weighted heavily on the quantities of nitrogen, sulfur, phosphorus, potassium, zinc, and copper, whereas factor 2 was weighted heavily on the quantities of zinc, iron, and aluminum. Factor 1 varied by oak species, with Q. kelloggii having a higher factor 1 nutrient content than the other three species. Factor 2 response was higher in Q. kelloggii, Q. agrifolia, and Q. engelmannii than in Q. chrysolepis. The collective effects of four macronutrients (nitrogen, sulfur, phosphorus, and potassium) and two micronutrients (zinc and copper) suggest that these might be the nutrients directing preferential feeding of A. auroguttatus adults on the foliage of Q. kelloggii. Leaf toughness might also play an important role in feeding preference. Female A. auroguttatus did not show an ovipositional preference among the four oak species.  相似文献   

2.
    
Drosophila suzukii Matsumara (Diptera: Drosophilidae) is an invasive vinegar fly that infests ripe and ripening soft skinned fruits. In the south‐eastern United States, blackberry (Rubus spp.) crops are heavily impacted by D. suzukii, and current management tactics rely on the use of broad‐spectrum insecticides targeted to adult populations. An improved understanding of D. suzukii biology and ecology are necessary to create sustainable management options. Knowledge of how D. suzukii interacts with resources will enable targeted management actions in the future. In this present study, we monitored larval infestation throughout the blackberry canopy and found that infestation was highest in the inner portion of the canopy and lower in more exposed locations. We also documented higher humidity within the cane canopy relative to the edge of the field. A difference in abiotic conditions may create within‐crop microhabitats that D. suzukii is able to exploit. Future research will explore how to take advantage of these microhabitats in pest management programs.  相似文献   

3.
    
  • 1 Emerald ash borer Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) is an invasive forest insect pest threatening more than 8 billion ash (Fraxinus spp.) trees in North America. Development of effective survey methods and strategies to slow the spread of A. planipennis requires an understanding of dispersal, particularly in recently established satellite populations.
  • 2 We assessed the dispersal of A. planipennis beetles over a single generation at two sites by intensively sampling ash trees at known distances from infested ash logs, the point source of the infestations. Larval density was recorded from more than 100 trees at each site.
  • 3 Density of A. planipennis larvae by distance for one site was fit to the Ricker function, inverse power function, and the negative exponential function using a maximum likelihood approach. The prediction of the best model, a negative exponential function, was compared with the results from both sites.
  • 4 The present study demonstrates that larval densities rapidly declined with distance, and that most larvae (88.9 and 90.3%) were on trees within 100 m of the emergence point of the adults at each site. The larval distribution pattern observed at both sites was adequately described by the negative exponential function.
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4.
    
Goldspotted oak borer, Agrilus auroguttatus Schaeffer (Coleoptera: Buprestidae), is a new invasive species in southern California, USA. The extent of the host range of this insect is not known, but this knowledge will have a major impact on assessment of the risks that this pest poses to oaks [Quercus spp. (Fagaceae)]. We conducted laboratory tests to determine the potential suitability of native and ornamental oak species for larvae and adults of A. auroguttatus. We infested 179 cut logs (from 163 different trees) with eggs or larvae, measured neonate survival and, after 5 months, counted feeding galleries, and noted the proportion of galleries with late instars. Initial larval survival was generally high when larvae penetrated the phloem (range: 62–98% among oak species), and low by the time larvae began to feed at the phloem/xylem interface (range: 0–25% among oak species). The majority of larvae that established a visible feeding gallery survived to the fourth instar (total of 73% for all oak species). Larval galleries were established with greater frequency in red oaks (Section Lobatae) compared with other oaks (19 vs. 7 or 4%). All red oaks tested (Q. agrifolia Née, Q. kelloggii Newberry, and Q. wislizeni A. DC.) were likely suitable hosts for larvae. Larvae were apparently able to feed on some of the other oaks (Q. chrysolepis Leibmann, Q. suber L., Q. lobata Née, and Q. douglasii Hook & Arn), although it remains unclear whether these species would be preferred hosts under natural conditions. Adult longevity and fecundity varied little by species of oak foliage fed to adults. The host range of A. auroguttatus is likely limited by suitability of oak species for the larval rather than the adult life stage. Results support published field observations that red oaks are more suitable hosts than white oaks.  相似文献   

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Six microsatellite loci were isolated from the bruchid Acanthoscelides obtectus Say (Coleoptera: Bruchidae). Each locus was polymorphic, with the number of alleles ranging from 3 to 18. We found high levels of within‐population variation at most loci, with heterozygosities ranging from 0 to 0.75. Cross‐species amplification of these loci was tested in two other species of the genus Acanthoscelides, A. obvelatus Bridwell and A. argillaceus Sharp.  相似文献   

7.
  总被引:1,自引:0,他引:1  
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8.
    
Long‐lived tree species are genetically differentiated and locally adapted with respect to fitness‐related traits, but the genetic basis of local adaptation remains largely unresolved. Recent advances in population genetics and landscape genomic analyses enable identification of putative adaptive loci and specific selective pressures acting on local adaptation. Here, we sampled 60 evergreen oak (Quercus aquifolioides) populations throughout the species' range and pool‐sequenced 587 individuals at drought‐stress candidate genes. We analyzed patterns of genetic diversity and differentiation for 381 single nucleotide polymorphisms (SNPs) from 65 candidate genes and eight microsatellites. Outlier loci were identified by genetic differentiation analysis and genome–environment associations. The response pattern of genetic variation to environmental gradient was assessed by linear isolation‐by‐distance/environment tests, redundancy analysis, and nonlinear methods. SNPs and microsatellites revealed two genetic lineages: Tibet and Hengduan Mountains–Western Sichuan Plateau (HDM‐WSP), with reduced genetic diversity in Tibet lineage. More outlier loci were detected in HDM‐WSP lineage than Tibet lineage. Among these, three SNPs in two genes responded to dry season precipitation in the HDM‐WSP lineage but not in Tibet. By contrast, genetic variation in the Tibet lineage was related to geographic distance instead of the environment. Furthermore, risk of nonadaptedness (RONA) analyses suggested HDM‐WSP lineage will have a better capacity to adapt in the predicted future climate compared with the Tibet lineage. We detected genetic imprints consistent with natural selection and molecular adaptation to drought on the Qinghai–Tibet Plateau (QTP) over a range of long‐lived and widely distributed oak species in a changing environment. Our results suggest that different within‐species adaptation processes occur in species occurring in heterogeneous environments.  相似文献   

9.
  总被引:1,自引:0,他引:1  
Agrilus biguttatus Fabricius, Agrilus sulcicollis Lacordaire, and Agrilus angustulus Illiger (Coleoptera: Buprestidae) are three beetle species associated with oak trees [Quercus spp. (Fagaceae)] in Europe. In Hungary, all three species were observed in the foliage near freshly cut oak log piles. Agrilus biguttatus was active later in the afternoon, whereas the other species were observed earlier in the day. Dead female models of these three native Agrilus species, as well as the native species Agrilus cyanescens Ratzeburg and the non‐native Agrilus planipennis Fairmaire, were pinned onto adjacent leaves in direct sunlight to observe the visual mating approaches of the local male populations. Agrilus biguttatus and A. sulcicollis males flew toward and landed directly on the models from a distance of 1 m. Agrilus angustulus flew toward the models from a similar distance, but rather than landing directly on a model would alight on the leaf, 1–2 cm away, before walking closer to the model while antennating it. For all three species, there was substantial cross‐attraction to models of other species. Both A. biguttatus and A. sulcicollis males chose A. angustulus models less often than their respective conspecific models. Likewise, A. angustulus males approached A. sulcicollis models less often than their normal conspecific models. Agrilus biguttatus males attempted to copulate with both A. biguttatus and A. planipennis models, afterward remaining with them for several minutes. Agrilus biguttatus males spent more time on A. planipennis models than on conspecific models. Thus, there is substantial cross‐species attraction in visually mediated mating approaches and copulation behavior. These findings suggest a common behavioral template for visual mate‐finding among buprestids and a large degree of close‐range mating compatibility between A. biguttatus and A. planipennis.  相似文献   

10.
    
The invasive emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is a major pest of ash trees, Fraxinus spp., in its introduced range in North America. Field studies were conducted to quantify the efficacy of traps baited with kairomone and pheromone lures for early detection of A. planipennis infestation. A trapping experiment demonstrated that green traps baited with the kairomone (3Z)‐hexenol detected at least one adult A. planipennis in 55.3% of plots with ‘nil to low’‐density infestations and in 100% of plots with ‘moderate to high’‐density A. planipennis infestations. Mean trap captures increased significantly with increasing infestation density. In terms of the optimal number of traps per plot, when one (3Z)‐hexenol‐baited trap was placed per plot, the trap detected populations in 62% of the plots with ‘low to moderate’‐density infestations through branch sampling. Detectability was increased to 82% when two traps were placed per plot. Finally, addition of female‐produced (3Z)‐lactone pheromone to traps significantly increased detection rates at both the trap and plot level, as compared with traps baited with the host volatile, (3Z)‐hexenol, alone (88 vs. 60%, respectively). Our results are the first to demonstrate the efficacy of baited green sticky traps for detecting low‐density A. planipennis infestations, particularly when the (3Z)‐lactone pheromone is used. This combination is therefore recommended for development of early‐detection protocols against A. planipennis.  相似文献   

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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   

14.
硕黄吉丁属(Megaloxantha)包括了吉丁甲科(Buprestidae)最大的华丽种,体长可达70mm以上。C.Kerremans(1902)建立Megaloxantha是作为金吉丁属(Chrysochroa)的1个亚属,后来他修订这个复合类群时(1908-1909)将各作者的许多种归为3个种。J.Obenberger(1926)所发表的《鞘翅目名录,吉丁甲科Ⅰ》中也只认可了5种;与此同时,A.Thery(1926)又恢复了2个异名作为有效种,并提出了3个种为  相似文献   

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16.
    
Ecological speciation describes the evolutionary process whereby divergent natural selection between environments generates reproductive isolation. Studying the magnitude of sequential reproductive barriers between ecologically divergent populations improves our understanding of the way these barriers evolve and how each contributes to the speciation process. Immigrant inviability describes the lower fitness of immigrants in non‐native environments and is an important, but long underexplored, reproductive barrier. In this study, we test the role of immigrant inviability among host‐associated populations of the gall wasp Belonocnema treataeMayr (Hymenoptera: Cynipini: Cynipidae) by measuring the ability of gall wasps to initiate and complete gall formation, while avoiding host immune responses, on closely related native and non‐native live oaks, Quercus virginianaMill., Quercus fusiformisSmall, and Quercus geminataSmall (Fagaceae). In general, we found evidence for immigrant inviability when B. treatae populations colonized non‐native host species. However, patterns were variable among years, suggesting that episodic events may play an important role in connecting ecologically divergent populations.  相似文献   

17.
    
Nonnative ungulates can alter the structure and function of forest ecosystems. Feral pigs in particular pose a substantial threat to native plant communities throughout their global range. Hawaiian forests are exceptionally vulnerable to feral pig activity because native vegetation evolved in the absence of large mammalian herbivores. A common approach for conserving and restoring forests in Hawaii is fencing and removal of feral pigs. The extent of native plant community recovery and nonnative plant invasion following pig removal, however, is largely unknown. Our objective was to quantify changes in native and nonnative understory vegetation over a 16 yr period in adjacent fenced (pig‐free) vs. unfenced (pig‐present) Hawaiian montane wet forest. Native and nonnative understory vegetation responded strongly to feral pig removal. Density of native woody plants rooted in mineral soil increased sixfold in pig‐free sites over 16 yr, whereas establishment was almost exclusively restricted to epiphytes in pig‐present sites. Stem density of young tree ferns increased significantly (51.2%) in pig‐free, but not pig‐present sites. Herbaceous cover decreased over time in pig‐present sites (67.9%). In both treatments, number of species remained constant and native woody plant establishment was limited to commonly occurring species. The nonnative invasive shrub, Psidium cattleianum, responded positively to release from pig disturbance with a fivefold increase in density in pig‐free sites. These results suggest that while common native understory plants recover within 16 yr of pig removal, control of nonnative plants and outplanting of rarer native species are necessary components of sustainable conservation and restoration efforts in these forests.  相似文献   

18.
    
While females often reject courtship attempts by heterospecific males, reproductive interference by harassment from such males can nonetheless occur, potentially reducing female fitness. Such effects may be profound following a range expansion, when males from a new species may suddenly encounter (and perhaps even become abundant relative to) females of related native species. Drosophila subobscura recently invaded North America and may impact native species through reproductive interference and other processes. We test for the potential for reproductive interference by D. subobscura males on D. persimilis females in the laboratory. D. subobscura males aggressively copulated with D. persimilis females, including many females that exhibit rejection behaviors. Despite females attempting to dismount the males, the heterospecific copulations are on average longer than conspecific copulations, and females exhibit some reluctance to remate with conspecific males following this harassment. Females confined with both conspecific and heterospecific males produce fewer adult progeny than those with either conspecific males only or with conspecific males and distantly related D. simulans males that do not engage in female harassment. Overall, our results illustrate how reproductive interference by an invasive species can have negative effects on resident natural populations.  相似文献   

19.
    
  1. The East Mediterranean region is a global biodiversity hotspot for vertebrates and plants. Although oaks (Quercus) are the dominant tree species in semi‐natural Mediterranean forests, the insect species richness associated with East Mediterranean oak forest has been insufficiently studied.
  2. Species richness and composition of the saproxylic beetle assemblage, including its seasonal variation, of a stand of old oaks (Quercus calliprinos) in northern Israel was investigated. Flight‐interception traps were used to sample beetles over a period of 2 years. In addition, a set of pitfall traps was placed in the trunk hollows in the second year of the study.
  3. Fifty‐two saproxylic beetle species were found associated with oaks in the field study. Among them, two saproxylic click‐beetle species were previously unknown to science, and eight species represent new records for Israel. Both the number of species and the number of individuals showed two distinct phenological peaks during the year.
  4. A preliminary list of saproxylic beetles inhabiting oaks in Israel was prepared and biogeographical distribution, host plants, habitat guild, and activity period are presented for each species. Together with our own data, the literature survey conducted for 19 beetle families established that at least 124 saproxylic beetle species are associated with oaks in Israel while about 40% of them are unique to the Levantine region. As most localities with old‐growth oak forest structures are small and isolated, ongoing management should have high priority despite the fact that these forests already receive protection.
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20.
    
The small hive beetle, Aethina tumida Murray (Coleoptera: Nitidulidae), is a recent but significant pest of honeybee [Apis mellifera L. (Hymenoptera: Apidae)] hives in various regions throughout the world, including Eastern Australia. The larval stage of this beetle damages hives when they feed on brood, pollen, and honeycomb, leaving behind fermented wastes. In cases of extreme damage, hives collapse and are turned to an odorous mass of larvae in fermenting hive products. The yeast Kodamaea ohmeri (Etchells & Bell) Yamada et al. (Ascomycota) has been consistently isolated from the fermenting material as well as each life stage of this beetle. Various studies have noted that the small hive beetle is attracted to volatiles from hive products and those of the yeast Kohmeri, although earlier studies have not used naturally occurring hive products as their source of fermentation. This study investigated changes through time in the attractiveness of natural honeybee hive products to the small hive beetle as the hive products were altered by the action of beetle larvae and fermentation by K. ohmeri. We used gas chromatography‐mass spectrometry and choice‐test behavioural assays to investigate these changes using products sampled from three apiaries. Attractiveness of the fermenting hive products (‘slime’) increased as fermentation progressed, and volatile profiles became more complex. Fermenting hive products remained extremely attractive for more than 30 days, significantly longer than previous reports. These results have strong implications for the development of an external attractant trap to assist in the management of this invasive pest.  相似文献   

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