中国大痣小蜂属食植群记述（膜翅目：长尾小蜂科）

本文报导中国大痣小峰属Ｍｅｇａｓｔｉｇｍｕｓ食植群Ｐｈｙｔｏｐｈａｇｏｕｓｇｒｏｕｐ１２种，其中包括５新种：黄杉大痣小蜂Ｍｅｇａｓｔｉｇｍｕｓｐｓｅｕｄｏｔｓｕｇａｐｈｉｌｕｓｓｐｎｏｖ（寄生华东黄杉Ｐｓｅｕｄｏｔｓｕｇａｇａｕｓｓｅｎｉｉ），拟海棠大痣小蜂Ｍｅｇａｓｔｉｇｍｕｓｐｓｅｕｄｏｍａｌｉｓｐ．ｎ．（寄主不明），基室大痣小蜂Ｍｅｇａｓｔｉｇｍｕｓｃｅｌｌｓｓｐ．ｎｏｖ．（寄主不明），滇柏大痣小蜂Ｍｅｇａｓｔｉｇｍｕｓｄｕｃｌｏｕｘｉａｎａｅｓｐ．ｎｏｖ．（寄生云南滇柏Ｃｕｐｒｅｓｓｕｓｄｕｃｌｏｕｘｉａｎａ）和横脊大痣小蜂Ｍｅｇａｓｔｉｇｍｕｓｃａｒｉｎｕｓｓｐ．ｎｏｖ．（寄生云南滇柏）；２中国新记录种：云杉大痣小蜂Ｍｅｇａｓｔｉｇｍｕｓｅｚｏｍａｔｓｕａｎｕｓ（寄生西伯利亚云杉Ｐｉｃｅａｏｂｖａｔａ），冷杉大痣小蜂Ｍｅｇａｓｔｉｇｍｕｓｌａｒｓｉｏｃａｒｐａｅ（寄生西伯利亚冷杉Ａｂｉｅｓｓｉｂｉｒｉｃａ）。新种模式标本存浙江农业大学生物防治研究室。

中国大痣小蜂属食植群种类特征及检索

本文列出我国大痣小蜂属食植群１２种的检索表并附图．

Modified Predator-Prey Model for Mealybug Population with Biological Control

Mealybugs are a major pest for many crops （such as the vegetable Cassava, in Thailand）. An environmentally-friendly bio-control method is implemented using an introduced predator （green lacewings） of the mealybugs to mitigate plant damage. This is analyzed so as to devise and determine an optimal strategy for control of the mealybug population. A predator-prey model has been proposed and analyzed to study the effect of the biological control of the spread of the mealybugs in the plant field. The behaviour of the system in terms of stability, phase space and bifurcation diagrams are considered. The results obtained from different numbers of predators being released are compared. In particular we obtain thresholds of introduced-predator level above which the prey is driven to extinction. Future models will include age-structured multi-compartments for both the prey and predator populations.

Herbivores alleviate the negative effects of extreme drought on plant community by enhancing dominant species

Aims Both extreme drought and insect herbivores can suppress plant growth in grassland communities.However,most studies have examined extreme drought and insects in isolation,and there is reason to believe that insects might alter the ability of grasslands to withstand drought.Unfortunately,few studies have tested the interactive effects of extreme drought and insect herbivores in grassland communities.Methods Here,we tested the drought–herbivore interactions using a manipulative experiment that factorially crossed extreme drought with the exclusion of insect herbivores in a temperate semiarid grassland in Inner Mongolia.Important Findings Our results demonstrated that both extreme drought and insect herbivores separately decreased total plant cover.When combined,insect herbivores reduced the impact of drought on total cover by increasing the relative abundance of drought-resistant dominant species.Our results highlight that the negative effect of extreme drought on total plant cover could be alleviated by maintaining robust insect herbivore communities.

Aboveground herbivory increases soil nematode abundance of an invasive plant

Aims Plant invasions have the potential to affect the community structure of soil nematodes,but little is known about whether such effects are mediated by aboveground herbivores since invasive plants are not completely released from herbivores in the introduced range.In this study,we explored how aboveground insect herbivores mediated the effect of invasive plant Alternanthera philoxeroides on soil nematodes and examined the temporal variations of such an herbivory-elicited effect.Methods We conducted a greenhouse experiment by applying different herbivory treatments(no insect herbivores,specialist Agasicles hygrophila and generalist Cassida piperata)to potted A.philoxeroides,and then measured the community compositions of soil nematodes in corresponding pots on the 1st,10th and 20th day after removal of all herbivores.In addition,the carbon content of roots and root exudate of A.philoxeroides were also measured.Important Findings Our results showed that aboveground herbivory significantly increased the abundance of soil nematodes of A.philoxeroides,likely plant feeder nematodes,after insect herbivores were removed immediately(1st day).However,such impacts waned with time and there was no significant difference at later stages(10th and 20th days).Furthermore,the effects of specialist A.hygrophila and generalist C.piperata herbivory were consistent on the abundance of soil nematodes.Overall,our results suggest that aboveground insect herbivores have the potential to alter the effects of plant invasions on soil nematodes,but such impacts are transient.Furthermore,our study highlighted the importance of integrating the effects of above-and belowground organisms when evaluating the impacts of plant invasions.