Rates of brood parasitism vary extensively among host species and populations of a single host species. In this study, we documented and compared parasitism rates of two sympatric hosts, the Oriental Reed Warbler （Ac...Rates of brood parasitism vary extensively among host species and populations of a single host species. In this study, we documented and compared parasitism rates of two sympatric hosts, the Oriental Reed Warbler （Acrocephalus orientalis） and the Reed Parrotbill （Paradoxornis heudei）, in three populations in China. We found that the Common Cuckoo （Cuculus canorus） is the only parasite using both the Oriental Reed Warbler and Reed Parrotbill as hosts, with a parasitism rate of 22.4%-34.3% and 0%-4.6%, respectively. The multiple parasitism rates were positively correlated with local parasitism rates across three geographic populations of Oriental Reed Warbler, which implies that higher pressure of parasitism lead to higher multiple parasitism rate. Furthermore, only one phenotype of cuckoo eggs was found in the nests of these two host species. Our results lead to two conclusions： （1） The Oriental Reed Warbler should be considered the major host of Common Cuckoo in our study sites; and （2） obligate parasitism on Oriental Reed Warbler by Common Cuckoo is specialized but flexible to some extent, i.e., using Reed Parrotbill as a secondary host. Further studies focusing on egg recognition and rejection behaviour of these two host species should be conducted to test our predictions.展开更多
The polyphagous B-biotype of Bemisia tabaci （Gennadius） has demonstrated a high capacity to adapt to numerous hosts from diverse plant families. To illustrate induced responses by the host plant, biochemical researc...The polyphagous B-biotype of Bemisia tabaci （Gennadius） has demonstrated a high capacity to adapt to numerous hosts from diverse plant families. To illustrate induced responses by the host plant, biochemical research on eight plant-insect interaction correlative enzymes, representing detoxifying, antioxidant and digestive pathways, were investigated. Transferring whitefly adults to Zhongmian 23 from the pre-adapted host Zhongmian 41 induced activities of carboxylesterase （by 1.80-fold）, glutathione S-transferase （by 3.79-fold）, proteinase （by 1.62-fold） and amylase （by 2.41-fold） activities, hut decreased polyphenol oxidase （by 1.89-fold） and peroxidase （by 1.88-fold）. However, transferring whitefly adults to the favorite host abutilon from Zhongmian 41 was associated with increased activities of cytochrome P450 monooxygenase （by 1.61-fold） and amylase （by 1.42-fold）, and decreased activities of polyphenol oxidase （by 2.96-fold） and peroxidase （by 2.07-fold）. Our results, together with previous studies, proved that multiple pathways are involved in coping with host shifts by polyphagous herbivores, and the taxonomic status and preference of the host transferred would affect which pathway would be induced. These results would represent a key challenge in developing long-term sustainable insect control strategies.展开更多
Invasion of the oriental fruit lfy, Bactrocera dorsalis, into new niches containing different food sources （a process referred to as host shift）, may cause population genetic differentiation and sympatric speciation...Invasion of the oriental fruit lfy, Bactrocera dorsalis, into new niches containing different food sources （a process referred to as host shift）, may cause population genetic differentiation and sympatric speciation. To attempt to infer that experimentally, test populations were established by transferring a subset of the original populations, which had been grown on banana for many generations, onto navel orange, and then subculturing the navel orange population and banana population for at least 20 generations. Four pairs of SSR primers with high polymorphism on laboratory strains were used to detect population genetic differentiation. All six tested populations （the 5th, 10th and 15th generations of B. dorsalis fed on banana and navel orange, respectively） were found to have low genetic diversity. Furthermore, the genetic diversity of the navel orange populations was found to decline after being crossed for several generations. Populations initially were deviated from Hardy-Weinberg equilibrium, however, equilibrium was achieved with increasing numbers of generations in both of the host populations. Limited gene lfows were found among the six populations. The Nei’s standard genetic distances between the two host populations of the same generation were initially low, but increased with generation number. Genetic distances between banana and navel orange populations of the same generation were lower than genetic distances between different generations grown on the same host plant. Analysis of molecular distance （AMOVA） results based on generation groups and host groups demonstrated that genetic variation among generations was greater than that between the two host populations. The results indicated that population genetic differentiation occurred after the host shift, albeit at low level. Biogeography and taxonomy of the B. dorsalis complex revealed that speciation of B. dorsalis might be tightly associated with host shift or host specialization of B. dorsalis following dispersal.展开更多
Aphis gossypii Glover shows obvious host specialization, with cucurbit- and cotton-specialized biotypes or host races in many regions. Because its annual natal hostcrops senesce earlier the cucurbit-specialized biotyp...Aphis gossypii Glover shows obvious host specialization, with cucurbit- and cotton-specialized biotypes or host races in many regions. Because its annual natal hostcrops senesce earlier the cucurbit-specialized biotype may suffer food deficiency. The method this biotype uses to overcome this challenge is still poorly understood. In orderto understand the potential of the cucurbit-specialized biotype aphids in host shift and usage, the performance of this biotype on cotton （Gossypium hirsutum）, a common butpoor quality host plant, was explored in this study. The cucurbit-specialized aphids could establish populations on cotton only when these plants had at least nine leaves, and subsequent populations developed rather slowly. The presence of whitefly populations on cotton improved the success rate of cucurbit-specialized aphids. The cucurbit-specialized aphidswere mainly distributed on the older leaves of cotton, with only a few settling on the upper leaves. The cucurbit-specialized aphids reared on cotton for 40, 54 and 61 days stillmaintained strong preference for their natal host plant, cucumber （Cucumis sativus）, rather than cotton, and their net reproductive rates and intrinsic rates of natural increase weredramatically lower when they were transferred onto new six-leaf cotton plants or detached leaves. Therefore, we concluded that the cucurbit-specialized aphids have the potentialto utilize mature or whitefly-stressed cotton plants, but that this feeding experience on cotton did not alter their specialization for cucurbits. Some cotton plants could act as atemporary host for the cucurbit-specialized aphids to overcome food deficiency arising from senescing cucurbits.展开更多
基金supported by the National Natural Science Foundation of China(31071938 and 31272328 to WL,31101646 and 31260514 to CY)Program for New Century Excellent Talents in University(NCET-10-0111 to WL)the United Foundation for Natural Science of National Natural Science Foundation of China and People's Government of Guangdong Province(U0833005 to ZZ)
文摘Rates of brood parasitism vary extensively among host species and populations of a single host species. In this study, we documented and compared parasitism rates of two sympatric hosts, the Oriental Reed Warbler （Acrocephalus orientalis） and the Reed Parrotbill （Paradoxornis heudei）, in three populations in China. We found that the Common Cuckoo （Cuculus canorus） is the only parasite using both the Oriental Reed Warbler and Reed Parrotbill as hosts, with a parasitism rate of 22.4%-34.3% and 0%-4.6%, respectively. The multiple parasitism rates were positively correlated with local parasitism rates across three geographic populations of Oriental Reed Warbler, which implies that higher pressure of parasitism lead to higher multiple parasitism rate. Furthermore, only one phenotype of cuckoo eggs was found in the nests of these two host species. Our results lead to two conclusions： （1） The Oriental Reed Warbler should be considered the major host of Common Cuckoo in our study sites; and （2） obligate parasitism on Oriental Reed Warbler by Common Cuckoo is specialized but flexible to some extent, i.e., using Reed Parrotbill as a secondary host. Further studies focusing on egg recognition and rejection behaviour of these two host species should be conducted to test our predictions.
基金supported by the National Natural Science Foundation of China(30800131)the Fundamental Research Funds for the Central Universities, China(2012ZYTS043)
文摘The polyphagous B-biotype of Bemisia tabaci （Gennadius） has demonstrated a high capacity to adapt to numerous hosts from diverse plant families. To illustrate induced responses by the host plant, biochemical research on eight plant-insect interaction correlative enzymes, representing detoxifying, antioxidant and digestive pathways, were investigated. Transferring whitefly adults to Zhongmian 23 from the pre-adapted host Zhongmian 41 induced activities of carboxylesterase （by 1.80-fold）, glutathione S-transferase （by 3.79-fold）, proteinase （by 1.62-fold） and amylase （by 2.41-fold） activities, hut decreased polyphenol oxidase （by 1.89-fold） and peroxidase （by 1.88-fold）. However, transferring whitefly adults to the favorite host abutilon from Zhongmian 41 was associated with increased activities of cytochrome P450 monooxygenase （by 1.61-fold） and amylase （by 1.42-fold）, and decreased activities of polyphenol oxidase （by 2.96-fold） and peroxidase （by 2.07-fold）. Our results, together with previous studies, proved that multiple pathways are involved in coping with host shifts by polyphagous herbivores, and the taxonomic status and preference of the host transferred would affect which pathway would be induced. These results would represent a key challenge in developing long-term sustainable insect control strategies.
基金supported by the National Basic Research Program of China (2009CB125903)the Innovation Fund for graduate student in Southwest University of China (kb2011014)
文摘Invasion of the oriental fruit lfy, Bactrocera dorsalis, into new niches containing different food sources （a process referred to as host shift）, may cause population genetic differentiation and sympatric speciation. To attempt to infer that experimentally, test populations were established by transferring a subset of the original populations, which had been grown on banana for many generations, onto navel orange, and then subculturing the navel orange population and banana population for at least 20 generations. Four pairs of SSR primers with high polymorphism on laboratory strains were used to detect population genetic differentiation. All six tested populations （the 5th, 10th and 15th generations of B. dorsalis fed on banana and navel orange, respectively） were found to have low genetic diversity. Furthermore, the genetic diversity of the navel orange populations was found to decline after being crossed for several generations. Populations initially were deviated from Hardy-Weinberg equilibrium, however, equilibrium was achieved with increasing numbers of generations in both of the host populations. Limited gene lfows were found among the six populations. The Nei’s standard genetic distances between the two host populations of the same generation were initially low, but increased with generation number. Genetic distances between banana and navel orange populations of the same generation were lower than genetic distances between different generations grown on the same host plant. Analysis of molecular distance （AMOVA） results based on generation groups and host groups demonstrated that genetic variation among generations was greater than that between the two host populations. The results indicated that population genetic differentiation occurred after the host shift, albeit at low level. Biogeography and taxonomy of the B. dorsalis complex revealed that speciation of B. dorsalis might be tightly associated with host shift or host specialization of B. dorsalis following dispersal.
文摘Aphis gossypii Glover shows obvious host specialization, with cucurbit- and cotton-specialized biotypes or host races in many regions. Because its annual natal hostcrops senesce earlier the cucurbit-specialized biotype may suffer food deficiency. The method this biotype uses to overcome this challenge is still poorly understood. In orderto understand the potential of the cucurbit-specialized biotype aphids in host shift and usage, the performance of this biotype on cotton （Gossypium hirsutum）, a common butpoor quality host plant, was explored in this study. The cucurbit-specialized aphids could establish populations on cotton only when these plants had at least nine leaves, and subsequent populations developed rather slowly. The presence of whitefly populations on cotton improved the success rate of cucurbit-specialized aphids. The cucurbit-specialized aphidswere mainly distributed on the older leaves of cotton, with only a few settling on the upper leaves. The cucurbit-specialized aphids reared on cotton for 40, 54 and 61 days stillmaintained strong preference for their natal host plant, cucumber （Cucumis sativus）, rather than cotton, and their net reproductive rates and intrinsic rates of natural increase weredramatically lower when they were transferred onto new six-leaf cotton plants or detached leaves. Therefore, we concluded that the cucurbit-specialized aphids have the potentialto utilize mature or whitefly-stressed cotton plants, but that this feeding experience on cotton did not alter their specialization for cucurbits. Some cotton plants could act as atemporary host for the cucurbit-specialized aphids to overcome food deficiency arising from senescing cucurbits.
