中国寄生于林木食叶害虫的短角平腹小蜂属(膜翅目,旋小蜂科)四新种记述

记述了短角平腹小蜂属Mesocomys Cameron(膜翅目,旋小蜂科)4新种:枯叶蛾短角平腹小蜂M.trabalae sp.nov.,短柄短角平腹小蜂M.breviscapis sp.nov.,落叶松短角平腹小蜂M.superansi sp.nov.,中华短角平腹小蜂M.sinensis sp.nov..它们均寄牛于我国重要的食叶害虫的卵.是重要的灭敌昆虫.同时,编制了我国矩角平腹小蜂属种的枪索表.     

Invertebrate communities in a tropical rain forest canopy in Puerto Rico following Hurricane Hugo

1. Canopy invertebrate responses to Hurricane Hugo, tree species, and recovery time were examined at the Luquillo Experimental Forest in Puerto Rico during 1991–92 and 1994–95. Six tree species representing early and late successional stages were examined in paired plots representing severe hurricane disturbance (most trees toppled) and light hurricane disturbance (all trees standing and most branches intact). 2. Hurricane disturbance affected invertebrate abundances significantly. Sap-suckers and molluscs were more abundant, and defoliators, detritivores, and emergent aquatic insects were less abundant in recovering tree-fall gaps than in intact forest during this 5-year period. These changes in functional organisation are consistent with comparable studies of arthropod responses to canopy removal during harvest in temperate forests. 3. Tree species also affected invertebrate abundances significantly, but invertebrate communities did not differ significantly between the three early successional and three later successional tree species. 4. Most taxa showed significant annual variation in abundances, but only two Homoptera species showed a significant linear decline in abundance through time, perhaps reflecting long-term trends during recovery. 5. Leaf area missing, an indicator of herbivore effect on canopy processes, showed significant seasonal and annual trends, as well as differences among tree species and hurricane treatments. Generally, leaf area missing peaked during the wet season each year, but reached its highest levels during an extended drought in 1994. Leaf area missing also tended to be higher on the more abundant tree species in each disturbance treatment. 6. Herbivore abundances and leaf area missing were not related to concentrations of nitrogen, phosphorous, potassium, or calcium in the foliage. 7. This study demonstrated that invertebrate community structure and herbivory are dynamic processes that reflect the influences of host species and variable environmental conditions.     

Biological control of Rhamnus cathartica: is it feasible? A review of work done in 2002–2012

Rhamnus cathartica (common buckthorn) is a shrub (or small tree) of Eurasian origin, which has become invasive in North America. Internal feeders and sap suckers were prioritized for biological control from over 30 specialized insects identified from the target plant in its native European range. Five leaf‐feeding moths were also considered for further investigations. Field observations and preliminary host range tests with the stem‐boring beetle Oberea pedemontana, the root‐boring moth Synanthedon stomoxiformis, the shoot‐tip‐boring moth Sorhagenia janiszewskae and the leaf‐feeding moths Ancylis apicella, A. unculana, Triphosa dubitata, Philereme transversata and P. vetulata confirmed that all of these species were lacking host specificity in no‐choice conditions. Choice oviposition tests carried out with most of the prioritized species to assess their ecological host range yielded unreliable results. Three psyllids, Trichochermes walkeri, Cacopsylla rhamnicolla and Trioza rhamni are promising in terms of host specificity, but are infected with the plant disease ‘Candidatus Phytoplasma rhamni’. Fruit‐ or seed‐feeding insects may present the best potential for biological control of buckthorn in directly reducing seed set and thus seedling establishment. However, it was not possible to obtain adult fruiting trees of native North American Rhamnus species for testing. It is concluded that there are no promising arthropod agents based on what is known to date. Pathogens could offer new opportunities for biological control of R. cathartica in North America.     

羽角姬小蜂属寄生林木食叶害虫的二新种记述(膜翅目,姬小蜂科)

记述了中国羽角姬小蜂属2新种:袋蛾羽角姬小蜂Sympiesis chaliloides sp.nov.与舟蛾羽角姬小蜂Sympiesis closterae sp.nov..袋蛾羽角姬小蜂Sympiesis chaliloieds sp.nov.寄生白囊袋蛾Chaliloides kondonis Matsumura的幼虫;舟蛾羽角姬小蜂Sympiesis closterae sp.nov.寄生杨扇舟蛾Clostera aanachoreta(Fabricius)的幼虫.文中描述了两新种的外部形态特征,绘制了部分形态特征图,并与近缘种进行了形态比较.模式标本保存于中国林业科学研究院昆虫标本馆.     

马尾松林食叶类群昆虫多样性及相互关系

广西凭祥地区主要的马尾松食叶害虫有马尾松毛虫Dendrolimus punctatus Walker、松茸毒蛾Dasychira axutha Collenette、松艺夜蛾Hyssia adusta Draudt、松尺蠖Ectropis bistortata Goze、松叶蜂(Diprinid)：对马尾松林食叶类群昆虫多样性、组成结构和动态变化规律的研究表明,无灾区各种食叶害虫的多样性较高,比例比较均匀,而常灾区多样性较低．以马尾松毛虫和松毒蛾为主,其它食叶害虫的比例都很小,偶灾区介于二者之间。非暴发期的多样性高可降低害虫的变动幅度。松毒蛾与松毛虫具有协同危害的特性,而其它几种马尾松食叶害虫对松毛虫产生一定的抑制作用：水平相互关系可能降低或增加松毛虫暴发的机会。增加食叶类群的多样性,不但可以通过竞争抑制松毛虫,还有利于增加天敌和整个群落的多样性,是松毛虫持续控制的研究方向。     

Effects of landscape complexity and stand factors on arthropod communities in poplar forests

The arthropod communities are influenced by both local conditions and features of the surrounding landscape. Landscape complexity and stand factors may both influence arthropod communities in poplar forests, but the multiscale effects of these factors on poplar defoliators and natural enemies are still poorly understood. We collected poplar arthropods at 30 sampling sites within five forest landscapes in Xinjiang, China, and assessed whether landscape complexity and stand factors influence species abundance and diversity of poplar arthropods. Landscape complexity was quantified by several independent metrics of landscape composition, configuration, and connectivity at three spatial scales. We also determined the most powerful explanatory variables and the scale effect of each arthropod. Results found that landscape complexity and stand factors had different effects on different poplar arthropod communities. Landscape complexity promoted natural enemies at different spatial scales, but it inhibited the population of poplar defoliators at the scale of 200 m. Specifically, the abundance and diversity of all defoliators decreased with increasing proportion of nonhost plants. Landscape diversity only had a negative effect on defoliator abundance. The shape complexity of habitat patches increased the abundance of carabid beetles but reduced the abundance of green leafhoppers and migratory locusts. The abundance and diversity of predators increased with increasing structural connectivity of forest landscape. Additionally, both the abundance and diversity of all defoliators were positively correlated with the average height of herbaceous plants. Diversity of all defoliators increased with increasing size of host trees. The distance from sampling site to the nearest village positively influenced the abundance and diversity of all predators. Arthropod abundance and diversity in poplar forests were driven by stand factors and landscape complexity. Therefore, maintaining complex shape and structural connectivity of habitat patches and keeping poplar stands away from the village are crucial for management of forest landscape to enhance natural enemies. And in order to reduce the abundance of defoliators in poplar forest, the diversity of surrounding habitat types should be promoted within 200 m radii.     

Species richness and abundance of defoliating Lepidoptera associated with Eucalyptus grandis in Brazil and their response to plant age

The present paper documents patterns of species richness and abundance in Lepidoptera associated with a Eucalyptus grandis plantation, and how these patterns relate to plant age. The large number of species collected (1385), the lack of dominant species and the absence of pest outbreaks during the survey may be related to the high level of plant diversity of the native forest reserves in the area. There was no clear pattern of seasonal variation in species richness, but there were seasonal fluctuations in abundance, with minor defoliator species prevailing in October at the start of the rainy season. Species richness and abundance of Lepidoptera were positively correlated, with both variables decreasing in older plantations. However, the greatest numbers of major outbreak species and minor eucalypt defoliators were observed in plants after the mid‐point (6 years old) of their cutting cycle (7–10 years). This may be because of a larger amount of better‐quality plant leaves after this mid‐point or the reduction in silvicultural management interventions at this period of the Eucalyptus cutting cycle. The abundance of the main outbreak species observed in the survey, Stenalcidia grosica Schaus (Geometridae), was negatively correlated with plant age. Nonetheless, the effect was weak (r = – 0.21, P = 0.03) and we were not able to find further significant correlations between plant age and abundance of the other most frequent and constant species that were collected.     

Yield loss at the different growth stages in soybean due to insect pests in Ghana

Insecticide protection at the vegetative, reproductive or both vegetative and reproductive (complete) crop growth stages and untreated control was used to assess yield loss due to insect pests at the different growth stages of soybean in Ghana from 2007–2009. The objectives were to determine the economic importance of the two major insect pest guilds in soybean, viz. defoliators and pod feeders, and when to apply control measures for maximum benefit. The defoliators recorded were Podagrica spp., Ootheca mutabilis (Shalberg), Zonocerus variegatus L., Sylepta derogata F., Spodoptera littoralis Boisduval, Amsacta spp. and Helicoverpa armigera Hübner. The pod feeders recorded were the pod-sucking bugs (PSBs) Riptortus dentipes F., Thyanta sp. Aspavia armigera F., Nezara viridula L. and Dysdercus völkeri Schmidt. Generally, insect densities, pod and seed damage were lower while seed yields were significantly greater and similar in plots that were protected at the reproductive stage against PSBs and those protected at both vegetative and reproductive stages. Yield loss ranged between 25.8 and 42.8% in untreated plots, 11.1 and 34.3% in plots that were protected at the vegetative stage, and 5.2 and 11.3% in plots that were protected at the reproductive stage. There was a consistent negative correlation between yield and numbers of PSBs as well as pod and seed damage. These results showed that PSBs that attack soybean at the reproductive stage were the most important insect pests limiting soybean yield in Ghana.     

Parasitoid assemblages reared from geometrid defoliators (lepidoptera: geometridae) of larch and fir in the alps

1 Geometrid larvae were collected from larch and fir in the Swiss Alps in 1991–94. Eight geometrid species were found in sufficient numbers to rear out parasitoids: Agriopis aurantiaria, Bupalus piniarius, Epirrita autumnata, Eupithecia lariciata, Odontopera bidentata, Lycia isabellae and Semiothisa liturata were collected from larch, and Puengeleria capreolaria was obtained from fir. 2 Parasitoid species belonging to five different guilds and four families were obtained; however, the taxonomic status of some of these is not completely resolved. 3 The parasitoid complex of the larch‐feeding species was totally different from that of Tortricidae and Tenthredinidae, which feed on the same host tree. In general, there was little overlap in the parasitoid complexes of the larch geometrids, with the most dominant parasitoid of each species reared from only one host. By contrast, many parasitoid species found during our study are also known to attack the same hosts or closely related hosts on different host tree species in different environments, suggesting that host specificity in geometrid parasitoids is more related to host taxonomy than to host plant or habitat.