Preliminary phylogeny of Encarsia Förster (Hymenoptera: Aphelinidae) based on morphology and 28S rDNA

Species of Encarsia F?rster (Hymenoptera: Aphelinidae, Coccophaginae) are economically important for the biological control of whitefly and armored scale pests (Hemiptera: Aleyrodidae, Diaspididae). Whereas some regional keys for identification of Encarsia species are now available, few studies have addressed relationships within this diverse and cosmopolitan genus because of unreliable morphological data. Nuclear sequences of the D2 expansion region of 28S rDNA were determined from 67 strains of 24 species representing 10 species groups of Encarsia, 2 strains of Encarsiella noyesi Hayat, and 1 strain of Coccophagoides fuscipennis Girault. Analysis of molecular data alone and combined with morphological data resolves many nodes not resolved by morphology alone and offer insights into which morphological characters are useful for supporting group relationships. All analyses that include molecular data reveal Encarsia to be paraphyletic with respect to Encarsiella. If monophyly of Encarsia is constrained, the relationships are the same but with a different root within Encarsia, and these trees are presented as an alternate hypothesis. The luteola and strenua species groups are shown by both morphological and molecular data to be monophyletic, whereas the inaron group, the E. nigricephala + luteola group, and the E. quericola + strenua group are supported only by molecular data. The aurantii and parvella species groups are not supported in any of the analyses. The utility of morphological characters for defining species group relationships is discussed.     

A revision of the Encarsia pergandiella species complex (Hymenoptera: Aphelinidae) shows cryptic diversity in parasitoids of whitefly pests

Encarsia pergandiella Howard, described from North America (USA), and Encarsia tabacivora Viggiani, described from South America (Brazil) (Hymenoptera: Aphelinidae), are two formally recognized taxonomic entities, that have been treated by several authors as synonyms due to lack of strong diagnostic characters. Taxonomy of these species is further complicated because several populations, geographically separated and differing in their biology, have been included under the concept of E. pergandiella. Among these, a population originally collected in Brazil and introduced to North America reproduces by thelytokous parthenogenesis and is infected by the symbiont Cardinium, while a morphologically indistinguishable population, naturally occurring in Texas, is biparental and infected by a related strain of Cardinium that induces cytoplasmic incompatibility. A third population known from California and introduced to the Old World is biparental and uninfected by intracellular symbionts. While adult females of the first two populations have entirely light yellow bodies and pupate face up (light form), those of the third population have largely brown bodies and pupate face down (dark form). Other dark form populations are known from Texas, Florida and New York. Because these parasitoids are economically important biological control agents of cosmopolitan whitefly pests, it is critical to characterize them correctly. In this study, we integrated molecular and morphometric analyses to substantiate observed differences in biological traits, and resolve the complicated taxonomy of this species complex. We sequenced the mitochondrial cytochrome c oxidase subunit I gene and the D2 region of the ribosomal 28S gene for individuals of both light form (from Texas and Brazil) and dark form (from California, Texas, Italy and Canary Islands) originating from laboratory cultures or collected in the field. Phylogenetic analysis unambiguously distinguished three well‐supported groups corresponding to the Texas light form, the Brazil light form and the dark form. Individuals of these three groups, in combination with all available type material (E. pergandiella, its synonym Encarsia versicolor Girault and E. tabacivora) and additional museum specimens of the dark form from New York and Italy, were subjected to multivariate morphometric analyses using Burnaby principal component analysis followed by a linear discriminant analysis, and multivariate ratio analysis. Overall, the analyses showed that: (i) E. pergandiella and E. tabacivora are two distinct species; (ii) the thelytokous Brazil light form corresponds to E. tabacivora; (iii) the biparental Texas light form is a new species formally described here as Encarsia suzannae sp.n. ; (iv) two new biparental species can be referred to the dark form, one described as Encarsia gennaroi sp.n. including the populations sampled in California, Texas, Italy and Canary Islands, and the other corresponding to the population from New York described as Encarsia marthae sp.n. A dichotomous key for both sexes of the species of the E. pergandiella complex is provided for identification. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:278475A0‐C2C4‐4400‐A042‐A5716457829D .     

中国寄生烟粉虱的三种恩角蚜小蜂28S rRNA系统发育分析(英文)

蚜小蜂Bemisia tabaci是烟粉虱的重要天敌, 其中双斑恩蚜小蜂Encarsia bimaculata, 丽蚜小蜂E. formosa以及浅黄恩蚜小蜂E. sophia是国内烟粉虱寄生蜂3个优势种。本研究以采自中国华南、 华东、 华北、 西南地区以及马来西亚、 埃及的E. bimaculata、 E. formosa和E. sophia 3个优势种的8个不同地理种群为研究对象, 对其28S rRNA D2和D3扩展区序列进行了测定和分析。结果表明： Encarsia属的恩蚜小蜂其28S rRNA D2和D3序列在种间水平上高度保守; 与丽蚜小蜂相比, 双斑蚜小蜂与浅黄恩蚜小蜂在遗传关系上更为接近。依据28S rRNA和D2序列的系统发育分析结果显示, 同一种的蚜小蜂其种内也存在一定的遗传分化, 比如中国广东的浅黄恩蚜小蜂种群与澳大利亚、 西班牙、 埃及和埃塞俄比亚的浅黄恩蚜小蜂种群接近, 而与泰国的种群的亲缘关系则较远。在系统发育树上, 来自不同国家的（苏丹、 埃及和危地马拉以及澳大利亚）的双斑蚜小蜂种群聚集在同一分支上; 同时, 来自中国衡水和昆明的丽蚜小蜂种群也与来自美国的丽蚜小蜂种群聚集在一起, 却与埃及的种群相距较远。对造成这种同种寄生蜂不同种群之间在遗传距离和地理距离不对称的原因进行了探讨。     

Encarsia or Encarsiella? – redefining generic limits based on morphological and molecular evidence (Hymenoptera,Aphelinidae)

Abstract.  The genus Encarsiella ( syn.n. ) (Hymenoptera, Chalcidoidea, Aphelinidae) is synonymized with Encarsia on the basis of molecular and morphological characters. A phylogenetic analysis was conducted of the D2 expansion region of the 28S ribosomal DNA including thirty-eight Encarsia species. Our phylogenetic analysis revealed a polyphyletic origin of Encarsiella and confirmed the results of earlier analyses indicating the paraphyly of Encarsia . Four species are described as new ( Encarsia bifasciata sp.n. , E. caelata sp.n. , E. obliqua sp.n. and E. pilosa sp.n. ). The following species are transferred from Encarsiella to Encarsia : Encarsia aleurodici ( Girault, 1916 ) comb.n. , E. amabilis ( Huang & Polaszek, 1998 ) comb.n. , E. boswelli ( Girault, 1915 ) comb.n. , E. magniclava ( Girault, 1915 ) comb.n. , E. narroi Gómez & García comb.n. , E. nepalensis ( Polaszek & Hayat, 1992 ) comb.n. , E. noyesi ( Hayat, 1983 ) comb.n. , E. pithecura ( Polaszek, 1999 ) comb.n. , E. tachii ( Polaszek & Hayat, 1992 ) comb.n. , E. taiwanensis ( Chou & Chou, 1994 ) comb.n. and E. tamaulipeca ( Myartseva & Coronado-Blanco, 2002 ) comb.n. The generic limits of Encarsia are re-defined based on a re-assessment of morphological characters, and the results are discussed with respect to the current classification of the aphelinid subfamily Coccophaginae.     

A revision of the Encarsia longifasciata species group (Hymenoptera: Aphelinidae)

Abstract.  The Encarsia longifasciata group is established and revised, and its relationship to other species groups of Encarsia is discussed with reference to biological, morphological and molecular evidence. Principal component analysis on all available specimens provided supporting evidence for the existence of five species, two of which are described herein as new: E. dewa Pedata & Polaszek, sp.n and E. prinslooi Pedata & Polaszek, sp.n. All species are either diagnosed or described, and illustrated, and information is given on their distribution and host range. Additional information on the biology and larval stages, and scanning electron micrographs of morphological details, are provided for E. arabica Hayat. A preliminary phylogenetic study using 28S D2 rDNA sequence data for E. arabica was inconclusive, but suggested possible affinities between the longifasciata and parvella species groups. An illustrated dichotomous key to all species of the E. longifasciata group is given.     

Invasion and Displacement of Experimental Populations of a Conventional Parasitoid by a Heteronomous Hyperparasitoid

Aphelinid parasitoids have an outstanding record of success in programmes of classical biocontrol against whiteflies and scale insects. Heteronomous hyperparasitoids are aphelinids in which the sexes develop on or in different hosts. The female always develops as a primary endoparasitoid of Homoptera. The male develops as a secondary parasitoid hyperparasitoid of his own or another species of homopteran endoparasitoid. Caged experiments were performed with the cabbage whitefly, Aleyrodes proletella, to examine the invasion of a population of a conventional parasitoid, Encarsia inaron both sexes primary endoparasitoids by a heteronomous hyperparasitoid, E. tricolor. In all cages the heteronomous hyperparasitoid successfully invaded an established population of the conventional parasitoid and the conventional species population declined to very low levels within 8 weeks of the introduction of the heteronomous hyperparasitoid. The patterns of invasion were different in each cage. In two cages, high levels of male production by E. tricolor were observed, indicating that hyperparasitism of the conventional species was probably an important factor in causing the decline in the E. inaron population. In a reciprocal experiment in which E. inaron was introduced to an established population of E. tricolor the conventional species failed to invade or persist. A survey of published references to complexes of parasitoids containing a heteronomous hyperparasitoid and one or more conventional species indicated that, in the majority of cases, the heteronomous hyperparasitoid was the most important species in the complex. There are clear implications for the use of these parasitoids in programmes of classical biocontrol. This is because high competitive ability against other parasitoids is not necessarily a good indicator of the ability of a species to maintain high levels of pest control, especially when hyperparasitic behaviour is involved.     

Classical biological control of ash whitefly: factors contributing to its success in California

The ash whitefly, Siphoninus phillyreae, invaded California in 1988 rapidly spreading throughout the state and infesting several species of ornamental trees and shrubs. Released Encarsia inaron rapidly established populations and spread throughout areas occupied by ash whitefly. We examined whether dispersal and overwintering ability could play a role in the extraordinary success of this parasitoid and we measured the impact of released parasitoids using a new method at a single location in northern California. The dispersal ability of E. inaron was examined by releasing two hundred and fifty adults 25 July 1991 into a single tree in a 1 ha pomegranate orchard near Brentwood, California. Based on yellow sticky card traps, the adult population spread at least 45 m from the release tree within 9 weeks of release. Over the same period of time the parasitoid population increased 64 fold. Impact was determined by measuring the number of ash whitefly adults produced in the absence and presence of E. inaron over 12 months. The production of whitefly adults, measured by the number of pupae entering the adult population, was reduced to very low numbers one year following the establishment of the parasitoid. Production of E. inaron adults increased rapidly, then decreased following the drop in production of ash whitefly adults. Duff of flowering pear trees was collected from under sample trees in mid winter to determine whether ash whitefly could survive on fallen leaves. Over fifty percent of adults emerged from whitefly pupae on leaves within 12 days of collection.     

Alt a 1 allergen homologs from Alternaria and related taxa: analysis of phylogenetic content and secondary structure

A gene for the Alternaria major allergen, Alt a 1, was amplified from 52 species of Alternaria and related genera, and sequence information was used for phylogenetic study. Alt a 1 gene sequences evolved 3.8 times faster and contained 3.5 times more parsimony-informative sites than glyceraldehyde-3-phosphate dehydrogenase (gpd) sequences. Analyses of Alt a 1 gene and gpd exon sequences strongly supported grouping of Alternaria spp. and related taxa into several species-groups described in previous studies, especially the infectoria, alternata, porri, brassicicola, and radicina species-groups and the Embellisia group. The sonchi species-group was newly suggested in this study. Monophyly of the Nimbya group was moderately supported, and monophyly of the Ulocladium group was weakly supported. Relationships among species-groups and among closely related species of the same species-group were not fully resolved. However, higher resolution could be obtained using Alt a 1 sequences or a combined dataset than using gpd sequences alone. Despite high levels of variation in amino acid sequences, results of in silico prediction of protein secondary structure for Alt a 1 demonstrated a high degree of structural similarity for most of the species suggesting a conservation of function.     

New species of Crotonia (Acari: Oribatida) from South Africa

Four new species of oribatid mites of the genus Crotonia , ( C. pauropelor sp. nov., C. dicella sp. nov., C. lyrata sp. nov. and C. ecphylla sp. nov. ) are described from soil and plant litter from South Africa. Crotonia pauropelor, C. dicella and C. ecphylla are allied to the 'capistrata' species-group, previously known only from Queensland, Australia, in that they possess the full complement of c setae on the notogaster. They differ in having eight pairs rather than nine pairs of genital setae. In addition, C. ecpylla is unusual in the genus Crotonia in that it appears to possess two pairs of setae on each of the second epimera. Crotonia lyrata has only two pairs of c setae and is allied to the 'cophinaria' species-group. This is only the second published record of the genus Crotonia from South Africa, and the first of any named species. A key to the African Crotonia species is provided, which includes the only two previously known species C. alluaudi and C. rothschildi (Berlese, 1916).     

云南拱背果蝇属双齿拱背果蝇种组--四新种记述及地理替代现象(双翅目:果蝇科)

概述了拱背果蝇属(Lordiphosa)中双齿拱背果蝇种组(denticeps species—group)的分类状况,并记述了分布在云南省的4个新种,即鹤颈拱背果蝇(Lordiphosa gruicollara sp.nov.),突拱背果蝇(Lordiphosa eminens sp.nov．),凹缘拱背果蝇(Lordiphosa incidens sp.nov．)和具毛拱背果蝇(Lordiphosa piliferous sp．nov．)。对目前在云南发现的该种组10个物种的地理分布做了初步分析,结果显示其分布呈明显的地理替代。模式标本均藏于北京大学生命科学学院。     

Molecular evidence for the hybrid origin of species in the soft coral genus Alcyonium (Cnidaria: Anthozoa: Octocorallia)

Several recent studies have suggested that hybridization may play a previously unrecognized and important role in the evolution of corals. Our observations of polymorphic and recombinant sequences in the multicopy ribosomal internal transcribed spacer (ITS) region suggested the possible hybrid origin of two European soft coral species, Alcyonium hibernicum and Bellonella bocagei. To examine this possibility further we cloned and sequenced ITS-1 from multiple individuals and populations of these two species as well as two sympatric congeners, A. coralloides and A. sp. M2. Phylogenetic analyses separated the observed sequence variants into two distinct clades. All A. coralloides sequences belonged to clade A, while A. sp. M2 had only clade B sequences. A majority of A. hibernicum individuals, however, contained both clade A and B sequences that were identical to the predominant sequence variants found in A. coralloides and A. sp. M2, respectively. This pattern of additivity suggests that A. hibernicum originated from a hybrid cross between A. coralloides and A. sp. M2, a hypothesis that is supported by its unusual mode of reproduction (meiotic parthenogenesis). The predominant sequence variant found in B. bocagei was a unique, derived clade B sequence; in addition, however, most individuals of this species also had copies of a sequence identified as a recombinant between clade A and clade B sequence types. The presence of this recombinant sequence in the B. bocagei genome suggests that this species may also be the product of past hybridization events within the clade. Reticulate evolution may explain the failure of several previous studies to resolve the phylogeny of these four species.     

Three new species of bipolar budding yeasts of the genus Hanseniaspora and its anamorph Kloeckera isolated in Thailand

In the course of a survey of yeast biodiversity in the natural substrates in Thailand, eight strains were found to represent three hitherto undescribed species of Hanseniaspora/Kloeckera . They were isolated from insect frass, flower, lichen, rotted fruit and rotted wood. Based on the morphological and physiological characteristics, and sequences of D1/D2 domain, six strains represent a single species of the genus Hanseniaspora , described as Hanseniaspora thailandica sp. nov. (type BCC 14938^T=NBRC 104216^T=CBS 10841^T), and another strain as Hanseniaspora singularis sp. nov. (type BCC 15001^T=NBRC 104214^T=CBS 10840^T). A further strain, which belongs to Kloeckera and does not produce ascospores, is described as Kloeckera hatyaiensis sp. nov. (type BCC 14939^T=NBRC 104215^T=CBS 10842^T). Strains belonging to H. thailandica sp. nov. differed by 17–19 nucleotide substitutions from Hanseniaspora meyeri , the closest species. DNA reassociation between the two taxa showed 30–48% relatedness. Kloeckera hatyaiensis sp. nov. and H. singularis sp. nov. differed by eight and 16 nucleotide substitutions with one gap from the nearest species, Hanseniaspora clermontiae and Hanseniaspora valbyensis , respectively.     

Molecular characterization of closely related species in the parasitic genus Encarsia (Hymenoptera: Aphelinidae) based on the mitochondrial cytochrome oxidase subunit I gene

The genus Encarsia F?rster includes parasitoid species that are effective natural enemies of whitefly and armoured scale insect agricultural pests. Within this genus, several species groups have been recognized on the basis of morphological similarity, although their monophyly appears uncertain. It is often difficult to separate morphologically similar species, and there is evidence that some species could in fact be complexes of cryptic species. Their correct identification is fundamental for biological control purposes. Recently, due to unreliability of morphological characters, molecular techniques have been investigated to identify markers that differentiate closely related species. In this study, DNA variation in an approximately 900 bp segment of the mitochondrial cytochrome oxidase subunit I (COI) gene was examined by both sequencing and PCR-RFLP. Two pairs of species that are difficult to distinguish morphologically were analysed: Encarsia formosa Gahan and Encarsialuteola Howard, belonging to the luteola group, and two populations of Encarsiasophia (Girault & Dodd) from Pakistan and Spain, belonging to the strenua group, recently characterized as cryptic species. High sequence divergence and species-specific restriction patterns clearly differentiate both species pairs. Parsimony analysis of the nucleotide sequences was also performed, including Encarsiahispida De Santis (luteola group) and Encarsia protransvena Viggiani (strenua group). Two monophyletic clades supporting the two groups of species considered were resolved. The results of this study support the use of the COI gene as a useful marker in separating species of Encarsia, for which morphological differences are subtle. Moreover, the COI gene appears potentially useful for understanding phylogenetic relationships in this genus.     

Species diversity of Onchidiidae (Eupulmonata: Heterobranchia) on the mainland of China based on molecular data

The identification of members of the Onchidiidae is based on morphological characters; this is often time-consuming and can be inconclusive. In order to explore the species diversity of onchidiids in China, we provide a phylogeny constructed using partial sequences of two mitochondrial genes (16S rRNA and COI) and one nuclear ribosomal RNA gene (28S rRNA) from 32 samples comprising five genera. The topology, using both Bayesian and Maximum Likelihood inference methods, showed that the taxa clustered in two main groups of six species, one of which included Platevindex mortoni, Platevindex sp. and Onchidium ‘struma’; the other included Paraoncidium reevesii, Onchidella sp. and Peronia verruculata. It is clear that COI will be useful in discriminating onchidiid species-group taxa.     

两种蚜小蜂对烟粉虱寄主的产卵选择性(英文)

双斑恩蚜小蜂和桨角蚜小蜂是华南地区烟粉虱的两种优势种寄生蜂。本文研究了两种寄生蜂对不同龄期烟粉虱寄主的产卵选择特性。结果表明:两种寄生蜂均可寄生烟粉虱的1~4龄若虫。当只有1个龄期的烟粉虱若虫存在时,双斑恩蚜小蜂更多地寄生3龄和4龄若虫,较少寄生1龄和2龄若虫;而桨角蚜小蜂则更多地寄生3龄和2龄若虫,较少寄生1龄和4龄若虫。在4个龄期若虫同时存在时,双斑恩蚜小蜂会明显增加对3龄和4龄若虫的产卵寄生,降低对1龄和2龄若虫的寄生;而桨角蚜小蜂则增加对2龄和3龄若虫的寄生,减少对1龄和4龄若虫的寄生。寄主植物的差异不影响这二种蚜小蜂对各龄期烟粉虱若虫的产卵选择倾向。结果提示,烟粉虱若虫3龄和4龄是双斑恩蚜小蜂最适宜的寄主,而桨角蚜小蜂最适宜的寄主是烟粉虱2龄和3龄若虫。     

两种蚜小蜂对烟粉虱寄主的产卵选择性（英文）

双斑恩蚜小蜂和桨角蚜小蜂是华南地区烟粉虱的两种优势种寄生蜂。本文研究了两种寄生蜂对不同龄期烟粉虱寄主的产卵选择特性。结果表明: 两种寄生蜂均可寄生烟粉虱的1～4龄若虫。当只有1个龄期的烟粉虱若虫存在时,双斑恩蚜小蜂更多地寄生3龄和4龄若虫,较少寄生1龄和2龄若虫;而桨角蚜小蜂则更多地寄生3龄和2龄若虫,较少寄生1龄和4龄若虫。在4个龄期若虫同时存在时,双斑恩蚜小蜂会明显增加对3龄和4龄若虫的产卵寄生,降低对1龄和2龄若虫的寄生;而桨角蚜小蜂则增加对2龄和3龄若虫的寄生,减少对1龄和4龄若虫的寄生。寄主植物的差异不影响这二种蚜小蜂对各龄期烟粉虱若虫的产卵选择倾向。结果提示,烟粉虱若虫3龄和4龄是双斑恩蚜小蜂最适宜的寄主,而桨角蚜小蜂最适宜的寄主是烟粉虱2龄和3龄若虫。     

New data on the systematics of the palaearctic species of the <Emphasis Type="Italic">Dolichopus signifier</Emphasis> group (Diptera,Dolichopodidae)

Three new species of the genus Dolichopus Latr. (Diptera, Dolichopodidae) are described. All these species are closely related to Dolichopus signifer Haliday, 1832 and form a species-group including this species. Dolichopus taimyricus sp. n. is described from the southern tundra of the Taimyr Peninsula (northern Central Siberia); D. zlobini sp. n. was collected in the Pamirs (Tajikistan) and D. asymmetricus sp. n., in the mountains of Kazakhstan, Tajikistan, and Uzbekistan. A key to all these species of the group is given.     

Interspecific host discrimination and within-host competition between Encarsia formosa and E. pergandiella (Hymenoptera: Aphelinidae), two endoparasitoids of whiteflies (Hemiptera: Aleyrodidae)

Interspecific host discrimination and within-host competition between Encarsia formosa Gahan and Encarsia pergandiella (Howard), two endoparasitoids of whiteflies, were studied under laboratory conditions. Interspecific host discrimination was studied at two time intervals (0 h and 72 h after the first species had oviposited). Parasitized and unparasitized Trialeurodes vaporariorum (Westwood) hosts were accepted for oviposition at the same rate by the two parasitoid species. Host type did not affect the handling time of the two parasitoids. The outcome of within-host competition was investigated after females of the two species parasitized the hosts at various time intervals. In four treatments, E. pergandiella was allowed to oviposit 0, 24, 48 and 72 h after E. formosa while in the other two, E. formosa was allowed to oviposit 0 and 72 h after E. pergandiella. In four of these treatments: E. formosa following E. pergandiella at 0 and 72 h, and E. pergandiella following E. formosa at 0 and 24 h, E. pergandiella prevailed. In the host discrimination experiment (72 h interval), 20% of E. pergandiella eggs were killed by E. formosa females. Interspecific ovicide was also observed in the within-host competition experiment, in which 6% of 72-h-old E. pergandiella eggs were killed by E. formosa females.