Morphological and genetic relationship of two closely‐related giant water bugs: Appasus japonicus Vuillefroy and Appasus major Esaki (Heteroptera: Belostomatidae)

The East Asian giant water bug species Appasus japonicus Vuillefroy and Appasus major Esaki are aquatic hemipteran insects whose ranges overlap, particularly in the Japanese Archipelago and on the Korean Peninsula. In rare cases, the two species co‐occur. Furthermore, they are very similar ecologically and also morphologically, making their identification extremely difficult, and the possibility of hybridization has also been suggested. In the present study, we re‐examined their taxonomic validity, and the characteristics useful for identifying them. To re‐examine the morphological traits useful for distinguishing these two species, 222 specimens of A. japonicus collected from Japan, Korea, and China, and 132 specimens of A. major from Japan and Korea, were examined. We also performed molecular phylogenetic analyses based on the mitochondrial DNA 16S rRNA and cytochrome oxidase subunit I (COI) regions and the nuclear DNA Histone 3 region. Although the two species are very similar ecologically and also morphologically, they showed significant genetic differentiation. Thus, there is likely some form of reproductive isolation acting between them. Major morphological characteristics overlap extensively between A. japonicus and A. major, and no particular trait was identified as being effective for differentiating these species. All the morphological characteristics examined overlapped between A. japonicus and A. major. However, a principal component analysis based on all of the morphological characteristics revealed that, despite the overlap between these species, it was possible to morphologically distinguish them. Therefore, a more accurate identification becomes possible using multiple characteristics rather than a single characteristic. The male genital paralobes, evaluated as the most useful morphological characteristic, was effective with 100% probability for the Japanese Appasus species. However, for the Asian (i.e. Korean) specimens, this characteristic was not useful. On the other hand, the results of molecular phylogenetic analyses based on the mitochondrial DNA 16S rRNA and COI regions and the nuclear DNA Histone 3 region clearly showed significant genetic differentiation between the two species. Notably, the results for the mitochondrial COI region strongly supported the independence of each monophyletic group (i.e. validity of each species). Therefore, DNA barcoding based on the mitochondrial DNA COI region is also considered useful for the identification of A. japonicus and A. major. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110 , 615–643.     

Winter host exploitation influences fitness traits in a parasitoid

Organisms can either evade winter's unfavourable conditions by migrating or diapausing, or endure them and maintain their activities. When it comes to foraging during winter, a period of scarce resources, there is strong selective pressure on resource exploitation strategy. Generalist parasitoids are particularly affected by this environmental constraint, as their fitness is deeply linked to the profitability of the available hosts. In this study, we considered a cereal aphid–parasitoid system and investigated (1) the host–parasitoid community structure, host availability, and parasitism rate in winter, (2) the influence of host quality in terms of species and instars on the fitness of the aphid parasitoid Aphidius rhopalosiphi De Stefani‐Perez (Hymenoptera: Braconidae: Aphidiinae), and (3) whether there is a detectable impact of host fidelity on parasitism success of this parasitoid species. Host density was low during winter and the aphid community consisted of the species Rhopalosiphum padi L. and Sitobion avenae Fabricius (both Hemiptera: Aphididae), both parasitized by A. rhopalosiphi at non‐negligible rates. Aphidius rhopalosiphi produced more offspring when parasitizing R. padi compared with S. avenae, whereas bigger offspring were produced when parasitizing S. avenae. Although aphid adults and old larvae were significantly larger hosts than young larvae, the latter resulted in higher emergence rates and larger parasitoids. No impact of host fidelity on emergence rates or offspring size was detected. This study provides some evidence that winter A. rhopalosiphi populations are able to take advantage of an array of host types that vary in profitability, indicating that host selectivity may drop under winter's unfavourable conditions.     

Developing and applying a macroinvertebrate‐based multimetric index for urban rivers in the Niger Delta,Nigeria

Urban pollution of riverine ecosystem is a serious concern in the Niger Delta region of Nigeria. No biomonitoring tool exists for the routine monitoring of effects of urban pollution on riverine systems within the region. Therefore, the aim of this study was to develop and apply a macroinvertebrate‐based multimetric index for assessing water quality condition of impacted urban river systems in the Niger Delta region of Nigeria. Macroinvertebrate and physicochemical samples were collected from 11 stations in eight river systems. Based on the physicochemical variables, the stations were categorized into three impact categories namely least impacted stations (LIS), moderately impacted stations (MIS) and heavily impacted stations (HIS). Seventy‐seven (77) candidate metrics were tested and only five: Hemiptera abundance, %Coleoptera + Hemiptera, %Chironomidae + Oligochaeta, Evenness index and Logarithm of relative abundance of very large body size (>40–80 mm) were retained and integrated into the final Niger Delta urban multimetric index (MINDU). The validation dataset showed a correspondence of 83.3% between the index result and the physicochemically‐based classification for the LIS and a 75% correspondence for the MIS. A performance of 22.2% was recorded for the HIS. The newly developed MINDU proved useful as a biomonitoring tool in the Niger Delta region of Nigeria and can thus be used by environmental managers and government officials for routine monitoring of rivers and streams subjected to urban pollution.     

中国牡蛎蚧属一新种记述(半翅目:盾蚧科)

记述中国牡蛎蚧属1新种——浙江牡蛎蚧Lepidosapheszhejiangensis,sp.nov.。模式标本存于中国科学院上海生命科学院植物生理生态研究所昆虫博物馆。     

拟菱纹叶蝉属一新种记述(半翅目:叶蝉科:殃叶蝉亚科)

记述拟菱纹叶蝉属HishimonoidesIshihara1新种,即苗岭拟菱纹叶蝉Hishimonoidesmiaolingensis,sp.nov.。模式标本保存于贵州大学昆虫研究所。     

中国粉蚧科一新纪录种(半翅目,蚧总科,粉蚧科)

高桥平粉蚧Balanococcus takahashi McKenzie原产于日本,该种为我国首次记录,标本采自北京结缕草Zoysiatenuifolia叶鞘下。文中除重描雌成虫形态特征外,还首次记述和图示了该种的一龄若虫。     

Mating compatibility, life-history traits, and RAPD-PCR variation in Bemisia tabaci associated with the cassava mosaic disease pandemic in East Africa

The pandemic of a severe form of cassava mosaic virus disease (CMVD) in East Africa is associated with abnormally high numbers of its whitefly vector, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). To determine whether a novel B. tabaci biotype was associated with the CMVD pandemic, reproductive compatibility, fecundity, nymphal development, and random amplified polymorphic DNA (RAPD) variability were examined in, and between, B. tabaci colonies collected from within the CMVD pandemic and non-pandemic zone in Uganda. In a series of reciprocal crosses carried out over two generations among the six CMVD pandemic and four non-pandemic zone cassava B. tabaci colonies, there was no evidence of mating incompatibility. All the crosses produced both female and male progeny in the F₁ and F₂ generations, which in a haplo-diploid species such as B. tabaci indicates successful mating. There also were no significant differences between the sex ratios for the pooled data of experimental crosses, between individuals from two different colonies and control crosses between individuals from the same colony. Only one instance of mating incompatibility occurred in a control cross between cassava B. tabaci from Uganda and cottonB. tabaci from India. Measures of fecundity of the pandemic and non-pandemic zone B. tabaci on four cassava varieties showed no significant differences in their fecundity, nymphal development or numbers surviving to adult eclosion. Cluster analysis of 26 RAPD bands using six 10-mer primers was concordant with the mating results, grouping the pandemic and non-pandemic zone colonies into a single large group, also including a B. tabaci colony collected from cassava in Tanzania. These results suggest that it is unlikely that the severe CMVD pandemic in East Africa is associated with a novel and reproductively isolated B. tabaci biotype.     

扁蚜亚科昆虫虫瘿多样性研究(半翅目,蚜科)

虫瘿是蚜虫诱导植物异速生长的结果,虫瘿作为蚜虫重要的延伸特征,对蚜虫系统分类、系统发育关系、以及起源演化等研究具有非常重要的作用.而且虫瘿的形态结构、着生部位等在蚜虫的物种间存在非常丰富的多样性,是蚜虫重要的生物学特征,也是物种鉴定的重要依据之一.本文在已有标本采集记录和资料的基础上,从结瘿的植物、虫瘿着生部位、形态结构及类型等4个方面对扁蚜亚科虫瘿的多样性进行了系统研究.结果表明该亚科蚜虫大多都在原生寄主上形成虫瘿,个别属及种可在次生寄主上成瘿;虫瘿在类型上有虫瘿和伪虫瘿之别;在着生部位上,有叶片、叶脉、叶柄、小枝、粗枝等;虫瘿的形状也十分多样,有管状、袋状、球状、半球形、刺球状、纺锤形、圆锥形、分支状、香蕉束状等;在结构上既有单室、多室之分,也有开放型、封闭型之别.对于虫瘿多样性的研究,可为虫瘿演化规律的探讨提供重要信息,也是基于虫瘿进行物种鉴定的重要基础.     

Carotenoids of hemipteran insects,from the perspective of chemo-systematic and chemical ecological studies

Carotenoids of 47 species of insects belonging to Hemiptera, including 16 species of Sternorrhyncha (aphids and a whitefly), 11 species of Auchenorrhyncha (planthoppers, leafhoppers, and cicadas), and 20 species of Heteroptera (stink bugs, assassin bugs, water striders, water scorpions, water bugs, and backswimmers), were investigated from the viewpoints of chemo-systematic and chemical ecology. In aphids, carotenoids belonging to the torulene biosynthetic pathway such as β-zeacarotene, β,ψ-carotene, and torulene, and carotenoids with a γ-end group such as β,γ-carotene and γ,γ-carotene were identified. Carotenoids belonging the torulene biosynthetic pathway and with a γ-end group were also present in water striders. On the other hand, β-carotene, β-cryptoxanthin, and lutein, which originated from dietary plants, were present in both stink bugs and leafhoppers. Assassin bugs also accumulated carotenoids from dietary insects. Trace amounts of carotenoids were detected in cicadas. Carotenoids of insects belonging to Hemiptera well-reflect their ecological life histories.     

中国柔突叶蝉属二新种记述(半翅目,叶蝉科)

记述柔突叶蝉属Abrus Dai et Zhang 2新种,即雷公山柔突叶蝉A.leigongshanensis sp.nov.和凹板柔突叶蝉Abrus concavelus sp.nov..新种模式标本保存于贵州大学昆虫研究所.