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81.
Conservation of 16 nuclear microsatellite loci, originally developed for Quercus macrocarpa (section Albae), Q. petraea, Q. robur (section Robur), and Q. myrsinifolia, (subgenus Cyclobalanopsis) was tested in a Q. infectoria ssp. veneris population from Cyprus. All loci could be amplified successfully and displayed allele size and diversity patterns that match
those of oak species belonging to the section Robur. At least in one case, limited amplification and high levels of homozygosity support the occurrence of “null alleles” caused
by a possible mutation in the highly conserved primer areas, thus hindering PCR. The sampled population exhibited high levels
of diversity despite the very limited distribution of this species in Cyprus and extended population fragmentation. Allele
sizes of Q. infectoria at locus QpZAG9 partially match those of Q. alnifolia and Q. coccifera from neighboring populations. However, sequencing showed homoplasy, excluding a case of interspecific introgression with
the latter, phylogenetically remote species. Q. infectoria ssp. veneris sequences at this locus were concordant to those of other species of section Robur, while sequences of Quercus alnifolia and Quercus coccifera were almost identical to Q. cerris. 相似文献
82.
Molecular mapping of gene Gm-6(t) which confers resistance against four biotypes of Asian rice gall midge in China 总被引:2,自引:0,他引:2
S. K. Katiyar Y. Tan B. Huang G. Chandel Y. Xu Y. Zhang Z. Xie J. Bennett 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(6-7):953-961
The Chinese rice cultivar Duokang #1 carries a single dominant gene Gm-6(t) that confers resistance to the four biotypes of Asian rice gall midge (Orseolia oryzae Wood-Mason) known in China. Bulked segregant analysis was performed on progeny of a cross between Duokang #1 and the gall
midge-susceptible cultivar Feng Yin Zhan using the RAPD method. The RAPD marker OPM06(1400) amplified a locus linked to Gm-6(t). The locus was subsequently mapped to rice chromosome 4 in a region flanked by cloned RFLP markers RG214 and RG163. Fine
mapping of Gm-6(t) revealed that markers RG214 and RG476 flanked the gene at distances of 1.0 and 2.3 cM, respectively. Another gall midge
resistance gene, Gm-2, mapped previously to chromosome 4, is located about 16 cM from Gm-6(t), to judge by data from a segregating population derived from a cross between Duokang #1 and the Indian cultivar Phalguna
that carries Gm-2. We developed a PCR-based marker-assisted selection kit for transfer of the Gm-6(t) gene into Ming Hui 63 and IR50404, two parental lines commonly used in hybrid rice production in China. The kit contains
PCR primer pairs based on the terminal sequences of the RG214 and RG476 clones. Polymorphism between Duokang #1 and the hybrid
parental lines was found at these markers after digestion of the PCR products with specific restriction endonucleases. The
kit will accelerate introduction of gall midge resistance into hybrid rice in China.
Received: 18 May 2000 / Accepted: 9 March 2001 相似文献
83.
Density-dependent mortality has been considered a symptom of intraspecific competition. We examined the occurrence of such
mortality in the early stages of gall induction by the gall midge Asphondylia aucubae Yukawa et Ohsaki (Diptera: Cecidomyiidae). Female midges deposit eggs into young fruit of the dioecious shrub Aucuba japonica Thunberg to induce gall formation. Each host fruit received 0–67 eggs (mean 18.5 eggs) from multiple females, whereas established
galls each contained one to ten larvae. Midges suffered intense mortality (65–90%) at the egg stage. Egg mortality occurred
even in fruit in which no larvae had hatched, suggesting that this mortality cannot be wholly attributed to larval interference.
Egg mortality was affected by fruit size, i.e., resource capacity. Midges distributed more eggs in larger fruit. Egg mortality
increased as the per-fruit density increased relative to fruit size. In contrast, the mortality of hatchlings was density-independent.
Our results suggest that A. aucubae intensely compete for gall-induction substrates, which are spatiotemporally rare resources. 相似文献
84.
Wolbachia are endosymbiotic bacteria that are widely present in nematodes and arthropods and sometimes have a significant impact on the evolution, ecology, and biology of their hosts. The co-occurrence of Wolbachia within both Cynipid gall wasps and their parasitoids has rarely been studied. In this study, we report the occurrence of six species of gall wasps and 10 species of their parasitoids in central China. Wolbachia detection using the wsp gene showed that Wolbachia infected two species of gall wasps as well as their parasitoids, indicating that horizontal transmission of Wolbachia occurs between gall wasps and their parasitoids. Given that parasitoids will kill their hosts, Wolbachia may be horizontally transferred from gall wasps to their parasitoids. Using multilocus sequence typing (MLST) analysis, five new strains of Wolbachia were identified, all of which belonged to supergroup A. The strains of Wolbachia that infected gall wasps were not the same as those that infected their parasitoids. This result indicated that Wolbachia may evolve independently in parasitoids after they have been transferred from the host gall wasps. 相似文献
85.
86.
Few spittlebug species are gall formers, but the Homoptera as a whole contain many gall‐forming species in many families. Nymphs of a spittlebug, Aphelaenus nigripectus (Aphrophoridae, Auchenorrhyncha, Homoptera), were observed to induce leaf‐roll galls on cherry trees (Prunus speciosa, P. × yedoensis and P. pendula cv. pendula (Rosaceae)) in late April in Kyoto, Japan. Aphelaenus nigripectus nymphs aggregated on the ventral surface of the young leaves, fed on the ventral (abaxial) midvein, and excreted masses of froth in the rolled leaves. In a field experiment, it was discovered that feeding of A. nigripectus nymphs can induce rolling of the cherry leaves, and that the rolled leaves may provide protection from desiccation to A. nigripectus nymphs. This is the first record of gall‐forming habits in Japanese spittlebugs. 相似文献
87.
Synchronization of gallers with host plant phenology 总被引:3,自引:0,他引:3
J. Yukawa 《Population Ecology》2000,42(2):105-113
In addition to various bottom-up effects, the synchronization of herbivores with their host plant phenology determines quality
and quantity of food resources and affects the preference–performance linkage and abundance of herbivores. The synchronization
has a more critical meaning for such short-lived galling insects as cecidomyiid adults and young aphid stem mothers than for
other insects. This review, first, presents general information about gall midges and gall aphids, together with their life
history patterns and some ecological attributes. Second, some important topics of galling insect–host plant relation are briefly
reviewed. Then, synchronization patterns between gall midge emergence and host plant phenology are analyzed to discuss the
adaptive strategies of gall midges and to show how the amount of available food resources is affected by the time lag in synchronization.
The spatial distribution pattern and the preference–performance linkage of aphid stem mothers is also discussed in relation
to synchronization.
Received: October 2, 1998 / Accepted: July 3, 2000 相似文献
88.
1. Some insects have a prolonged diapause – a dormancy that extends over more than 1 year. In most species prolonged diapause involves one or a few extra years, but in extreme cases diapause may surpass 10 years. Few cases of very long diapause have been described, and very little is known about the population consequences of the temporal refuge formed by the diapausing individuals. 2. The gall midge Contarinia vincetoxici Kieffer galls the flowers of a long‐lived herb Vincetoxicum hirundinaria Med. After completing development, larvae leave the galls for the ground where they enter diapause. Extending an earlier published inoculation experiment, we show that the diapause may last up to at least 13 years, with a median duration of at least 6 years. 3. The gall midge is attacked by two parasitoid species. Dissections of gall midge larvae for presence of parasitoids revealed that Omphale salicis Haliday had a maximum 2 year diapause and Synopeas acuminatus Kieffer a maximum 4 years. The very long diapause of the gall midge may thus provide a temporal refuge from these enemies. 4. In a 15‐year field experiment all galls were removed every year from six isolated habitat patches. Density changes in experimental populations were not statistically different from control populations for over a decade. After 14–15 years a modest decline could be observed. This slow response illustrates that prolonged diapause in C. vincetoxici provides a very strong population buffer against mortality during the galling stage. 相似文献
89.
Biologists who study insect-induced plant galls are faced with the overwhelming diversity of plant forms and insect species. A challenge is to find common themes amidst this diversity. We discuss common themes that have emerged from our cytological and histochemical studies of diverse neotropical insect-induced galls. Gall initiation begins with recognition of reactive plant tissues by gall inducers, with subsequent feeding and/or oviposition triggering a cascade of events. Besides, to induce the gall structure insects have to synchronize their life cycle with plant host phenology. We predict that reactive oxygen species (ROS) play a role in gall induction, development and histochemical gradient formation. Controlled levels of ROS mediate the accumulation of (poly)phenols, and phytohormones (such as auxin) at gall sites, which contributes to the new cell developmental pathways and biochemical alterations that lead to gall formation. The classical idea of an insect-induced gall is a chamber lined with a nutritive tissue that is occupied by an insect that directly harvests nutrients from nutritive cells via its mouthparts, which function mechanically and/or as a delivery system for salivary secretions. By studying diverse gall-inducing insects we have discovered that insects with needle-like sucking mouthparts may also induce a nutritive tissue, whose nutrients are indirectly harvested as the gall-inducing insects feeds on adjacent vascular tissues. Activity of carbohydrate-related enzymes across diverse galls corroborates this hypothesis. Our research points to the importance of cytological and histochemical studies for elucidating mechanisms of induced susceptibility and induced resistance. 相似文献
90.
The life cycle and developmental stages of Aylax hypecoi (Trotter, 1913, Hymenoptera: Cynipidae: Aylacini) were studied in detail. Aylax hypecoi is known to induce galls in fruits of two Hypecoum species — H. imberbe and H. geslini (Papaveraceae) and the larva develops in host plant fruits. The morphology and development of egg, larva and pupa were investigated, which
has previously not been done. The shape and size of terminal-instar larvae and associated galls are sex-specific. Overwintering
stage, adult emergence and flying periods, and egg productivity were studied also. 相似文献