Beneficial interactions between insects and gut bacteria

Insects are amongst the most successful of animals, both in terms of diversity and in colonizing all ecological niches. Recent studies have highlighted the benefi ciary roles that bacteria play in the success and establishment of insects. By adopting techniques like 16S rRNA sequencing we are now in a position to understand the diversity of bacteria present in insect guts. It has been shown that some of these bacteria, like Wolbachia and Cardinium are involved in manipulating insect populations and distorting their sex ratio. Attempts have been made to culture these bacteria in insect cell lines, as they are recalcitrant to culture under normal microbiological conditions. The diversity of bacteria associated with insects and the functional role played by them in the insect is discussed below.     

蝽卵金小蜂属一新种记述(小蜂总科:金小蜂科:柄腹金小蜂亚科)

本文记述金小蜂科柄腹金小蜂亚科蝽卵金小蜂属一新种,正模、配模、副模,采自北京市平谷县。     

虫瘿与致瘿昆虫

虫瘿是由昆虫等致瘿生物诱导寄主植物而产生的一种特异组织。虫瘿对致瘿生物具有提供营养和保护等作用,虫瘿不仅有一定的经济利用和科学研究价值,而且多数致瘿昆虫是农林害虫。本文对致瘿昆虫在植物上的致瘿部位、致瘿的主要昆虫类群、虫瘿形态结构、虫瘿化学组成、虫瘿对寄主植物的影响以及虫瘿的利用等进行综述。     

Structure of yolk granules in oocytes and eggs of Blattella germanica and their interaction with vitellophages and endosymbiotic bacteria during granule degradation

Oocytes and embryos of the cockroach Blattella germanica were examined by optical and electron microscopy to study yolk granule degradation during embryo development. During vitellogenesis, progressively larger yolk granules are formed in the ooplasm and by chorionogenesis, the mature granules are packed so tightly that their shape is highly distorted. Throughout ovarian development, endosymbiotic bacteria lie at the follicle cell/oocyte interface. Just prior to chorionogenesis the endosymbionts transit the oocyte plasma membrane and cluster at the periphery. Bacteria become more numerous over the ventral region of the egg by day 1 postovulation and begin to invade the interior of the yolk mass from the ventral periphery. At that time, lysis of the nearby yolk granules occurs while those in the central ooplasm remain intact and free of bacteria up to day 4. Vitellophages become evident by day 2 postovulation. These cells are also distributed over the egg's periphery but are most numerous in the ventral region. Vitellophages, in association with the endosymbionts, protrude toward the yolk granules and extend filo- and lamellipodia over the granule surface. Portions of the yolk granules are then engulfed and sequestered as large vacuoles in the vitellophage's cytoplasm. The vacuoles then become vesiculated. As embryo development proceeds, the vesiculated portions partition into smaller multivesicular bodies. This study describes the dynamics of yolk granule-vitellophage interaction in embryos of B. germanica and suggests that yolk utilization entails the cooperative efforts of both vitellophages and endosymbiont bacteria.     

松针鞘瘿蚊在黑松冠层的空间分布特征与脱瘿节律研究

为掌握松针鞘瘿蚊Thecodiplosis japonensis幼虫在黑松冠层的分布特征和脱瘿节律,本文采用标准株调查法,调查了松针鞘瘿蚊幼虫在冠层的不同方位的虫口密度.采用陷阱法,调查了不同时期越冬幼虫的下树数量.结果表明,在黑松树冠的顶梢、上层、中层、下层,松针受害率分别为67.42％、68.59％、52.22％和...     

Endosymbiotic purple non-sulphur bacteria in an anaerobic ciliated protozoon

Abstract The marine ciliate Strombidium purpureum Kahl harbours endosymbiotic purple non-sulphur bacteria. The bacteria contain bacteriochlorophyll a and the carotenoid spirilloxanthin, and they have photosynthetic membranes and cell walls. The ciliates require light for survival and growth under anaerobic conditions; in the dark the cells prefer microaerobic conditions. The ciliates show a photosensory behaviour, and they accumulate in light at wave lenghts corresponding to the absorption spectrum of the symbionts. The findings are discussed in terms of theories on the endosymbiotic origin of mitochondria.     

Infection dynamics of different Wolbachia-types within one host population

Wolbachia are widespread intracellular symbionts of arthropods which are known to cause several reproductive manipulations in their hosts, the commonest of which being cytoplasmic incompatibility (CI), male killing (MK), and the induction of parthenogenesis (PI). Strains of endosymbionts inducing one of these effects can be referred to as 'Wolbachia-types'. Here, we try to ascertain whether two of these Wolbachia-types can stably coexist within one population. We investigate this question by means of two discrete-time mathematical models which describe the dynamics of an infection of a host population with either CI- and MK- or CI- and PI-Wolbachia. We derive analytical solutions for two special cases of each model showing that stable coexistence of the respective Wolbachia-types is not possible if no doubly infected individuals occur within the population and that stable coexistence is possible when doubly infected hosts do exist and transmission of the endosymbionts is perfect. Moreover, we show that a population infected with either CI- or MK-Wolbachia at equilibrium can resist invasion of the respective other Wolbachia-type as a single infection. In contrast, a population infected with CI-Wolbachia can be invaded by PI-Wolbachia as a single infection with the CI-Wolbachia going extinct. Computer simulations confirmed these findings for the general models. We discuss our results with respect to the prevalence of the Wolbachia-types considered here and the emergence of PI- from CI-Wolbachia.     

安徽稻田小蜂分科检索（膜翅目：小蜂总科）

对中国安徽芜湖稻田中的小蜂总科进行了分类研究,共发现9科12属,编制了分科检索表,提供了各科主要的分类特征图。     

中国翠金小蜂属分类研究及一新种记述（膜翅目：金小蜂科）

对中国翠金小蜂属Tritneptis Girault,1908进行了分类研究,共记述3种,包括1新种:类乌齐翠金小蜂Tritneptis riwoqensis JiaoXiao sp.nov.。提供了形态描述、分布和形态特征图,以及该属中国纪录种的分种检索表。研究标本保存于中国科学院动物研究所动物标本馆。