Self-/conspecific discrimination and superparasitism strategy in the ovicidal parasitoid Echthrodelphax fairchildii （Hymenoptera： Dryinidae）

Superparasitism in solitary parasitoids results in fatal competition between the immature parasitoids, and consequently only one individual can emerge. In the semisoli- tary ovicidal parasitoid Echthrodelphaxfairchildii （Hymenoptera： Dryinidae）, 2 adults can emerge under superparasitism with a short interval （〈24 h） between the first and second ovipositions. We determined the female parasitoid＇s behavioral responses under self- and conspecific superparasitism bouts with first-to-second oviposition intervals of 〈2 h. The self- and conspecific superparasitizing frequencies increased up to an oviposition interval of 0.75 h, with the former remaining lower than the latter, particularly for oviposition intervals of _〈0.25 h, suggesting the existence of self-/conspecific discrimination. The superparasitizing frequency plateaued for oviposition intervals of _〉0.75 h, with no dif- ference between self- and conspecific superparasitism. The ovicidal-probing frequency did not differ under self- and conspecific superparasitism, and was usually 〈20%. The females exhibited no preference for the oviposition side （i.e., ovipositing on the side with or without the first progeny） and almost always laid female eggs for any oviposition in- terval under self- and conspecific superparasitism. The sex ratio was not affected by the type of superparasitism, oviposition sides, or the occurrence of ovicidal probing. These observed results about the oviposition side, ovicidal probing, and sex ratios differed from the predictions obtained assuming that the females behave optimally. Possible reasons for the discrepancies are discussed： likely candidates include the high cost of selecting oviposition sides and ovicidal probing, and, for the sex ratio, the low frequency of encountering suitable hosts before superparasitism bouts.     

昼夜不对称变暖对陆地生态系统的影响

昼夜不对称变暖指的是白天和夜间的增温幅度不同，夜间温度升高的比白天快，全球大部分地区存在昼夜不对称变暖的现象。以往关于气候变暖对生态系统影响的研究大多建立在全天对等增温的基础上，缺乏对白天和夜间增温不对称性影响的深入研究。一些研究表明，白天增温和夜间增温对生态系统的作用机制不同，进而产生不同的影响。本文梳理了近期的研究进展，综述了昼夜不对称变暖对植物物候、生态系统碳循环、生物群落以及植被生产力等方面的特异性影响及其机理机制，并引述了不对称变暖对高寒生态系统碳循环可能产生的影响。在总结研究基础上，提出未来关于不对称变暖的影响研究应重视一些生态学规律的普适性验证，例如夜间增温下“光合补偿作用”,关注高寒冻土区土壤的碳积累和释放过程，深入剖析生物多样性与生态系统生产力稳定性间的关系等，提升我们对全球气候变暖影响的理解和认知。     

雌性红颊獴昼夜活动模式与天气的关系