Echinothrips Americanus Research Articles

Predatory efficacy ofDicyphus erranson different prey

The Palaearctic predator Dicyphus errans (Hemiptera: Miridae) lives omnivorously on various host plants, preying on a wide range of small arthropods, including some new invasive alien species. These characteristics make it a promising biological control agent (BCA) in organic greenhouses. The capacity of a BCA to find, kill and consume prey plays a fundamental role in trophic interactions and population dynamics in a predator-prey system. The functional response of a predator, which describes how the individual rate of prey consumption changes in response to prey density, is a key component to assess its effectiveness in pest control and the stability of its own populations. Therefore, the functional response of D. errans on different prey was studied to improve our knowledge on the potential of this mirid, which is naturally widespread in European organic greenhouses. Laboratory experiments were carried out on three exotic pests: the poinsettia thrips Echinothrips americanus (Thysanoptera: Thripidae), the greenhouse whitefly Trialeurodes vaporariorum (Hemiptera: Aleyrodidae), and the tomato borer Tuta absoluta (Lepidoptera: Gelechiidae), to build functional response curves. Prey was offered at different densities to single females of D. errans for 24 h. The predation behaviour of D. errans on all the prey species was defined by Type II functional response curves. The female could daily prey about 62 adults of E. americanus, 114 pupae of T. vaporariorum, and 236 eggs of T. absoluta. The high voracity of this generalist predator on different prey confirmed its suitability as a BCA. For effective and stable pest control strategies, a prior to pest establishment of D. errans in organic greenhouses may prevent pest escaping in case of high infestation rates, even if the type II functional response reaches saturation at very high prey densities.

Genomovirus Genomes Recovered from Echinothrips americanus Sampled in Florida, USA.

ABSTRACTFour genomovirus genomes were recovered from thrips (Echinothrips americanus) collected in Florida, USA. These represent four new species which are members of the Gemycircularvirus (n = 2), Gemyduguivirus (n = 1), and Gemykibivirus (n = 1) genera. This is the first record, to our knowledge, of genomoviruses associated with a phytophagous insect.

Reproductive Behavior of Echinothrips americanus (Thysanoptera: Thripidae).

Most Thysanoptera possess a haplo-diploid reproductive mode and reproduce via arrhenotoky. Females can mature eggs successively throughout almost their entire life, but in most terebrantian thrips spermiogenesis is complete by adult male eclosion, and testes contain only mature spermatids. In parasitoid wasps this phenomenon of preadult spermiogenesis is described as prospermatogeny. It is unclear if prospermatogeny and this predetermined sperm quantity have implications for mating strategy and fitness. In this study, we give a detailed description of mating behavior of the thripine species Echinothrips americanus, which largely corresponds with the only available data of another species of this family, Frankliniella occidentalis (Thysanoptera: Thripidae). With investigations using light microscopy, we describe for the first time the chronological sequence of internal processes during copulation. The release of male accessory gland material followed subsequently by spermatozoa indicates production of a female-determined type 1 spermatophore. Despite prospermatogeny, males are able to inseminate 10 females with an equal amount of spermatozoa. It is only the quantity of glandular material that decreases with the number of previous copulations. Based on these new findings, the reproductive strategy of this species is discussed.

Male Pheromones Influence the Mating Behavior of Echinothrips americanus.

Two dibasic esters, the dimethyl ester of hexanedioic acid (dimethyl adipate, DBE-6) and the dimethyl ester of pentanedioic acid (dimethyl glutarate, DBE-5) were found in head-thorax extracts of male Echinothrips americanus. DBE-5 induced abdomen wagging and raising in males and females, which is typically exhibited when encountering a male. DBE-6 was avoided by males and was detected on mated, but not on virgin, females. Both substances applied to virgin females lead to females being ignored by males. The role of both substances is discussed with regard to the male mating system.

Offspring sex ratio and development are determined by copulation activity in Echinothrips americanus MORGAN 1913 (Thysanoptera: Thripidae)

AbstractThe costs of parthenogenetic reproduction are more or less unknown in thrips. However, IPM strategies require an understanding of temporal and spatial life‐history variations and sex ratios. Hence, different circumstances with regard to mating and sperm storage, and their effects on the life history of the adults and progeny, were tested in Echinothrips americanus. Different conditions were investigated: (1) one female and one male with permanent access to each other, (2) one female and one male with limited access to each other, (3) one virgin male only, (4) one virgin female only and (5) two virgin females permanently associated. Mating or not mating has a significant effect on the longevity of females and males, and on female fecundity. As a result of tested condition (2), limited access has a positive effect on longevity of a male. On the other hand, permanent access (1) or no access to a female (3) leads to shorter longevity of a male. For a female with permanent access to a male (1), longevity and oviposition rate are reduced. In addition, test conditions of parents have a significant effect on developmental time of the offspring and their sex ratio. Compared to a female under condition (1), a female with limited access to a male (2) delivers offspring with a more male‐biased sex ratio, independent of the period of time after last male access. Concerning the time for development of the offspring, females under condition (2) and under condition (4) deliver an F1 generation with a shorter developmental time than those under condition (1). Therefore, E. americanus seems to have a feedback system, that is offspring in low male‐biased populations develop faster and generate an adapted sex ratio. Hence, the assumption of a lower infestation risk in arrhenotokous than in thelytokous parthenogenesis should be reconsidered.

Sternal gland structures in males of bean flower thrips, Megalurothrips sjostedti, and Poinsettia thrips, Echinothrips americanus, in comparison with those of western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae)

Sternal pores are important features for identification of male thrips, especially within the subfamily Thripinae. They vary in shape, size and distribution even between species of one genus. Their functional role is speculated to be that of sex- and/or aggregation pheromone production. Yet, sexual aggregations are not reported in Echinothrips americanus, known to have sternal pores, while we observed aggregations in Megalurothrips sjostedti, previously reported to lack them.We examined the sternal glands and pores of the thripine species E. americanus and M. sjostedti males, in comparison with those of Frankliniella occidentalis using light microscopy, as well as scanning and transmission electron microscopy. Pore plates of F. occidentalis were ellipsoid and medial on sternites III–VII, while in E. americanus they were distributed as multiple micro pore plates on sternites III–VIII. In M. sjostedti they appeared as an extremely small pore in front of the posterior margin of each of sternites IV–VII. Pore plate and pore plate area were distributed similarly on sternites III–VII in F. occidentalis. However, in E. americanus the total pore plate area increased significantly from sternites III to VIII. Ultrastructure of cells associated with sternal glands showed typical characteristics of gland cells that differ in size, shape and number. The function of sternal glands is further discussed on the basis of morphological comparisons with other thrips species.

宮崎県で初確認されたモトジロアザミウマに対する薬剤の殺虫効果 およびスワルスキーカブリダニの捕食量

2014年に宮崎県の施設ピーマンでモトジロアザミウマが初確認された。今後の再発生時の防除対策に活かすため，本種に対する各薬剤の殺虫効果とスワルスキーカブリダニの補食量を調査した。成幼虫ともに補正死虫率が約90％以上だった薬剤は，メソミル，ニテンピラム，スピネトラム，スピノサド，アバメクチン，エマメクチン安息香酸塩，クロルフェナピル，トルフェンピラドの８剤であった。また，幼虫対象の薬剤ではスピロテトラマト，フルフェノクスロンおよびルフェヌロンの死虫率が97.2～100％と高かった。ニテンピラム，スピノサド，エマメクチン安息香酸塩のLC50値は，各37.1ppm，1.0ppm，1.5ppm であり，ニテンピラムのLC50値が高いことから今後の薬剤抵抗性の発達が懸念される。また，モトジロアザミウマ１齢幼虫は，スワルスキーカブリダニ雌成虫１頭に2.8±1.0頭/ 日捕食され，ミナミキイロアザミウマの7.2±1.9頭/ 日よりも有意に少なかった。

Post-Mating Interactions and Their Effects on Fitness of Female and Male Echinothrips americanus (Thysanoptera: Thripidae), a New Insect Pest in China

Post-mating, sexual interactions of opposite sexes differ considerably in different organisms. Post-mating interactions such as re-mating behavior and male harassment can affect the fitness of both sexes. Echinothrips americanus is a new insect pest in Mainland China, and little is known about its post-mating interactions. In this study, we observed re-mating frequency and male harassment frequency and their effects on fitness parameters and offspring sex ratios of E. americanus females. Furthermore, we tested the impact of mating and post-mating interactions on fitness parameters of males. Our results revealed that the re-mating frequency in female adults was extremely low during a 30-day period. However, post-mating interactions between females and males, consisting mainly of male harassment and female resistance, did occur and significantly reduced female longevity and fecundity. Interestingly, increased access to males did not affect the ratio of female offspring. For males, mating dramatically reduced their longevity. However, post-mating interactions with females had no effects on the longevity of mated males. These results enrich our basic knowledge about female and male mating and post-mating behaviors in this species and provide important information about factors that may influence population regulation of this important pest species.

Poznanie sekwencji rDNA i analiza filogenetyczna wciornastka cyklamenowca (Thrips major Uzel)

Thrips major is a polyphagous insect, which occurs on each continent. In Poland T. major usually attacks crops, ornamental plants and herbs. Although it is very common pest, there are only few fragments of its sequence available. Knowledge about its rDNA (ribosomal deoxyribonucleic acid) sequence is needed to develop new diagnostic methods that could allow for successful differentiation between T. major and other thrips species such as Frankliniella occidentalis and Thrips tabaci, which post higher risk to cultivations in Poland. The aim of this work was the characterization of rDNA sequence of T. major, its comparison with other thrips species’ sequences followed by phylogenetic analysis. In this work new PCR (polymerase chain reaction) primers were designed which enabled rDNA fragment amplification from most of Thripinae subfamily species. PCR reaction was carried out and obtained products of amplification were sequenced, followed by bioinformatic analysis. Then, T. major 18S-ITS1-5,8S-ITS2-28S rDNA region sequences were compared with already known sequences of following thrip species: T. tabaci, T. palmi, Scirtothrips dorsalis, Echinothrips americanus, Frankliniella schulzei, F. occidentalis and F. intonsa and phylogenetic analyses were performed. Thrips major jest polifagiem występującym na wszystkich kontynentach. W Polsce bytuje zarówno na roślinach uprawnych, jak i na roślinach ozdobnych i ziołach. Pomimo powszechnego występowania, niewiele fragmentów jego genomu zostało zsekwencjonowanych. Znajomość sekwencji rDNA (ribosomal deoxyribonucleic acid – rybosomalnego kwasu deoksyrybonukleinowego) jest istotna dla opracowania diagnostyki molekularnej umożliwiającej skuteczne odróżnienie go od innych gatunków wciornastków, stanowiących większe zagrożenie dla upraw na terenie Polski, m.in. Thrips tabaci i Frankliniella occidentalis. Celem pracy było poznanie sekwencji regionu 18S-ITS1-5,8S-ITS2-28S rDNA wciornastka T. major oraz jego analiza porównawcza i filogenetyczna. W pracy zaprojektowano parę starterów uniwersalnych dla wielu gatunków z podrodziny Thripinae, umożliwiającą powielenie fragmentu rDNA T. major. Przeprowadzono reakcje PCR (polymerase chain reaction – łańcuchową reakcję polimerazy), a uzyskane w nich produkty poddano sekwencjonowaniu. Wyniki analizowano przy pomocy narzędzi bioinformatycznych. Uzyskane sekwencje T. major zestawiono z poznanymi wcześniej sekwencjami takich gatunków, jak: T. tabaci, T. palmi, Scirtothrips dorsalis, Echinothrips americanus, Frankliniella schulzei, F. occidentalis i F. intonsa oraz przeprowadzono analizy filogenetyczne.

美洲棘蓟马对不同蔬菜寄主的偏好性

比较了美洲棘蓟马对12种不同蔬菜和1种非蔬菜的偏好性,并通过对数线性模型和方差分析对结果进行了分析。结果显示美洲棘蓟马成虫对13种寄主植物的寄主偏好性及产卵选择性具有显著差异。该虫成虫在南瓜上分布最多,平均每株寄主植物达到23.5头,在油菜上的产卵量最大,每株达50.3粒。黄瓜、南瓜、油菜、黄豆和辣椒上成虫分布量每株均在10头以上,显著多于其他寄主;而上述5种寄主上的每株产卵量也均在30粒以上,显著多于除豆角以外的其它寄主。该虫在黄瓜上发育最快,15d左右即可完成其整个未成熟期;在辣椒上未成熟期存活率最高,为80.1%。上述结果将为该虫入侵风险的评估提供重要依据。;<em>Echinothrips americanus</em> Morgan (Thysanoptera: Thripidae) was recently (2010) found in the Beijing area and Yangling, Shaanxi Province, China. Current studies report that this thrips uses 48 families-106 species-as host plants, most of which are ornamental plants in the Araceae, Euphorbiaceae, and Apocynaceae families. The host preferences of this thrips among vegetable plants have rarely been studied. The preference for and suitability of 13 potential crop hosts of <em>E. americanus</em> were studied in the laboratory by comparing adult host selection, oviposition preference, and developmental and survival rates. Twelve vegetable species, i.e., <em>Vigna unguiculata</em>, <em>Glycine max</em> (Leguminosae), <em>Daucus carota</em>, <em>Foeniculum vulgare</em> (Apiaceae), <em>Solanum melongena</em>, <em>Capsicum frutescens</em>, <em>Solanum lycopersicum</em> (Solanaceae), <em>Cucumis sativus</em>, <em>Cucurbita moschata</em> (Cucurbitaceae), <em>Brassica chinensis</em>, <em>Brassica campestris</em>, and <em>Brassica oleracea</em> (Brassicaceae), and one non-vegetable host, <em>Medicago sativa</em> (Fabaceae) were tested. One to two weeks-old plants of each crop were grown in a greenhouse into which 100 thrips were released, and plants were examined for thrips infestation daily. The host-plant and oviposition selection data were analyzed with a log-linear model and variance analysis using the software DPS v13.5. The host and oviposition preference of the thrips to the 13 different plant species differed significantly. The most adults were found on <em>C. moschata</em>, with 23.5 per plant, while the plant with the most eggs was <em>C. frutescens</em>, with 50.32 per plant. No adults were found on <em>F. vulgare</em>, <em>B. oleracea</em>, or <em>M. sativa</em>. There were significantly more adults on <em>C. sativus</em>, <em>C. moschata</em>, <em>B. chinensis</em>, <em>G. max</em>, and <em>C. frutescens</em>, more than 10 per plant, than on the other host plants. Additionally, there were significantly more eggs on those five host species-more than 30 per plant-than on other plants, except <em>V. unguiculata</em>. There were no eggs on <em>D. carota</em>, <em>B. oleracea</em>, or <em>M. sativa</em>, suggesting that this thrips does not lay eggs on these plants. There was a positive correlation between the amounts of adults and eggs on the plants; there were usually large numbers of eggs on the plants with many adults. Among the different life stages, eggs required the longest development time, from 6 to 9 days. The developmental duration of prepupae on different host plants was less than 2 days, while the pupal instar persisted longer than the prepupal one. The complete immature phase of the life cycle lasted from 15-17 days on different host plants. Among the tested host plants, this thrips developed fastest on <em>C. sativus</em>, requiring 15.09 days to maturity, and slowest on <em>G. max</em>, with a duration of 16.77 days. The survival rates of the first and second instars were lower (74.6%-94.4%) than those of the prepupae and pupae (93.3%-100%). The first instar had the highest survival rates (94.4%) on <em>B. chinensis</em> and <em>C. frutescens</em> and the lowest rate (74.6%) on <em>C. moschata</em>. Overall, <em>E. americanus</em> had the highest survival rate in the immature stage (80.1%) on <em>C. frutescens</em> and the lowest survival rate (64.3%) on <em>G. max</em>. Our results suggested that <em>C. sativus</em>, <em>C. moschata</em>, <em>B. chinensis</em>, <em>G. max</em>, and <em>C. frutescens</em> were the preferred hosts of <em>E. americanus</em>. This information provides an important basis for assessing the economic threat and invasive potential of this thrips.

Methyl jasmonate and Echinothrips americanus regulate coumarin accumulation in leaves of Matricaria chamomilla

Abstract Matricaria chamomilla synthesize ( Z )- and ( E )-2-s- d -glucopyranosyloxy-4-methoxy cinnamic acid (GMCA), the biosynthetic precursors of herniarin. During leaf development the content of ( E )-GMCA decreased and no changes were found in the content of other compounds evaluating in the experiments. Methyl jasmonate elicits an increase in ( E )-GMCA and herniarin content in young growing leaves as well as mature and senescing leaves 48 h after treatment. In contrast, attack by the thrips, Echinothrips americanus , causes increase not only in GMCAs and herniarin content but also in the amount of coumarin, umbelliferone. The results confirmed that coumarin-like metabolites can be considered as plant defence compounds in biotic and abiotic stress conditions.

Predatory Behavior of Phytophagous Thrips on Asian citrus Psyllid, Diaphorina citri, and citrus Leafminer, Phyllocnistis citrella (Hemiptera: Psyllidae/Lepidoptera: Gracillariidae)

In the present note, the predatory behavior of Echinothrips americanus on Diaphorina citri nymphs, as well as of Thrips tabaci on Phyllocnistis citrella larvae is described. The observations indicate that E americanus individuals were feeding on D citri nymphs, which were finally killed. Nymphs of 1 st , 2 nd and 3 rd instar found to be much more susceptible on E americanus attack compared with the nymphs of 4 th and 5 th instar. In the case of T tabaci and P citrella, notwithstanding the fact of feeding, as well as the disturbance of larvae were obvious, no lethal effects were observed.

Comparisons of Developmental and Reproductive Biology Between Parthenogenetic and SexualEchinothrips americanus(Thysanoptera: Thripidae)

Echinothrips americanus Morgan, an invasive pest on various ornamentals and greenhouse crops, was introduced into mainland China recently, posing a potential threat to ornamentals and greenhouse crops. It exhibits two different reproductive modes: arrhenotokous parthenogenesis and sexual reproduction. Laboratory studies were conducted to compare the developmental and reproductive biology of E. americanus in these two reproductive modes. Results showed that the oviposition period, and longevity of female adults using sexual reproduction were longer than those using parthenogenesis. Furthermore, sexual female adults had higher fecundity and survival rates. However, no significant differences were found among immature stages in the durations of first and second instars, prepupae, and pupae between the two reproductive modes, with the exception of the duration of the egg stadium. The survival rates for eggs and first and second instars were higher in sexual E. americanus whereas there were no survival differences for prepupae and pupae. These results provide valuable insights into the mechanisms of parthenogenesis and sex determination in Thysanoptera.

Larval and adult food preferences of the poinsettia thrips Echinothrips americanus Morgan, 1913 (Thysanoptera: Thripidae)

Numerous occurrence of Echinothrips americanus Morgan, 1913, a relatively newly established pest in European greenhouses, on a wide spectrum of cultivated plants throughout Slovakia has encouraged us to present current data on its food ecology. Analysing 1,650 plant species, the poinsettia thrips was found on 106 species (48 families) including 19 showing sporadic, 75 moderate and 17 high infestation. Larvae were detected on 25 plant taxa from 13 families, most of them being new hosts. Mature clusters of Acalypha hispida, showing moderate to high infestation level and carrying both larvae and adults, were selected for more detailed statistical evaluation. Preference of adults for upper and lower leaf surface tends to be without statistical significance, the larvae on the contrary were strongly related to the lower side (Pearson’s χ2 = 13.3552, P = 0.0013). Concerning the age, increased occurrence was apparent on younger leaves for both larvae and adults. For larvae the nonparametric test gives the statistical difference between three age categories of leaves with the following values: Kruskal–Wallis χ2 = 6.6384, P = 0.03618. The statistical significance of age seems to be more crucial for younger shoots, as proved by the statistics for both larvae (Kruskal–Wallis χ2 = 8.4852, P = 0.0144) and adults (Kruskal–Wallis χ2 = 7.1049, P = 0.0287). Different food preferences of larvae and adults may result in specific approach when applying an effective biological or chemical control. Narrower tolerance of larvae could make them more manageable target in plant protection instead of efforts to control the whole thrips population.

New Record of Thrips Species Associated with Soybeans in Puerto Rico

This is the first record of Caliothrips phaseoli Hood, Frankliniella gossypiana Hood and, Echinothrips americanus (Morgan) attacking soybean, Glycine max (L.) Merrill, in Puerto Rico. These species have not been reported previously in the island (Matorell 1976; Medina 2003). Thrips are important pests in many soybean production areas due to the feeding injury caused by larvae and adults and the indirect damage caused by transmission of tospoviruses (Almeida et al. 2003; Gent et al. 2004). Soybeans are mainly grown in winter nurseries in Puerto Rico with approximately 1,000 acres. During the 2006-2007 seasons, 3 replicated sentinel plots of soybeans were monitored for arthropods in Adjuntas, Isabela, and Juana Diaz, and soybean seedlings were evaluated in greenhouse conditions at Rio Piedras. Thrips were abundant in leaves and flowers in the 4 locations, but the new species record came from Juana Diaz and Rio Piedras. Soybean line 2053A was sampled every 7 d in V2 to R5 growth stage in 2 consecutive plantings in the sentinel plot. Thrips were collected from the plant tissue and placed in bottles with 70% ethyl alcohol. The insects were clarified with 5% potassium hydroxide for 30 s and mounted on slides with Canada balsam. Slides were dried at 30°C for 24 h. A Taxonomic Key for Thysanoptera was used for species identification and determination of sex for each specimen (Moritz et al. 2004; Mound & Marullo 1996). Five females of American bean thrips, Caliothrips phaseoli, were identified on soybean leaves at Juana Diaz in Nov 2006 and 2007. Adults were dark brown with 8 antennal segments (Fig. 1). Antennal segments III-V were yellow with brown shading apically. The head and pronotum have internal sculptured markings (Fig. 2). The pronotum has no long setae. Forewing brown with 3 subapically transverse bands and a subbasally white band. The medially band was light brown (Fig. 1). Forewing color at extreme apex dark. Forewing second vein with 6 setae (Fig. 3). Metanotum without campaniform sensilla. Metathoracic endofurca elongate and lyre shape (Fig. 4). Sculpture on lateral thirds of tergites III-VI comprised mainly of transverse parallel lines (Fig. 5). Tergite VIII with craspedum medially (Fig. 6). Caliothrips phaseoli has been reported as an economically important pest of soybean in Mexico and of dry beans in the United States and in Central and South America (Irwin et al. 1979; Mound & Marullo 1996). Echinothrips americanus was collected on soybean leaves from a greenhouse at Rio Piedras Experimental Station in 2007. Altogether, 20 specimens were collected with a sex radio of 1 male per 3 females. The adults were dark brown with 8 antennal segments. The head was prolonged in front of the compound eyes (Fig. 7). Head and pronotum with internal sculptured markings (Fig. 8). Metanotum reticulate, with median small setae that arise near to the anterior margin. Tergites II-VIII with pair of long setae medially (Fig. 9). Tergite VIII with a complete comb of slender microtrichia (Fig. 10). Sternites III-VIII on males each with small circular glandular areas (Fig. 11). Echinothrips americanus caused leaf chlorosis and bronzing when the population average was 16 adults per trifoliate (Fig. 12). Echinothrips americanus is a polyphagous leaf feeder reported as a pest in ornamental crops (Oetting et al. 1993). In Florida hosts included the beggar weed Desmodium tortuosum (Sul.) (Childers & Nakahara 2006). Frankliniella gossypiana was identified in soybean sentinel plots in Juana Diaz in Oct 2007. A total of 9 specimens (4 5 ) were collected from leaves and flowers. The adults were yellow with 8 antennal segments (Fig. 13). Antennal segment III pedicel simple (Fig. 14). Antennal VIII was 12 μm length and 4 μm width. Ocellar setae III arising within ocellar triangle (Fig. 15). Postocular setae IV large (Fig. 16). Pronotum was 162.5 μm length and anteromarginal setae was 50 μm length (Fig. 17). Tergite VIII with posteromarginal comb of microtrichia complete (Fig. 18). On the tergite X, B1 and B2 setae were 80 and 95 μm length, respectively. Frankliniella gossypiana is reported as a feeding on Phaseolus sp. and Pisum sp., in USA, Mexico, Nicaragua, and Peru (Maes 2007).

First interception of the greenhouse pest Echinothrips americanus Morgan, 1913 (Thysanoptera: Thripidae) in Slovakia

&lt;i&gt;Echinothrips americanus&lt;/i&gt; Morgan, 1913, is one of the pest species that expanded their area of distribution in a relatively short time. Being native to the eastern parts of North America, its first European interception was recorded in 1989. Since then it has invaded greenhouses in most European countries, including Slovakia, where it was first recorded in inspected material at the Botanical garden in Košice. As a polyphagous thrips with a wide host range it may induce damage mainly on ornamentals, although if low in numbers it can be easily overlooked. The species is a suitable example where preventive steps against its spread have not been sufficient enough which, therefore, demands further monitoring. Remarks on morphology, identification, economical importance and control are also given.

First Detection of &lt;I&gt;Wolbachia&lt;/I&gt; in Arrhenotokous Populations of Thrips Species (Thysanoptera: Thripidae and Phlaeothripidae) and Its Role in Reproduction

Insects in the order Thysanoptera are known for their haplodiploid reproduction, with most species reproducing by arrhenotoky. A few species, however, have only female populations and reproduce by thelytoky. Seven thrips species reproducing either by arrhenotoky [Frankliniella occidentalis (Pergande), Echinothrips americanus Morgan, Suocerathrips linguis Mound and Marullo, Gynaikothrips ficorum (Marchal)] or thelytoky [Hercinothrips femoralis (O.M. Reuter) and Parthenothrips dracaenae (Heeger)] or showing both reproduction modes (Thrips tabaci Lindeman) were screened for the presence of Wolbachia using 16S rDNA and ftsZ gene primers. The arrhenotokous reproducing species E. americanus, G. ficorum, and S. linguis tested positive for Wolbachia. The bacterium was not detected in F. occidentalis or T. tabaci; even the thelytokous population of T. tabaci was free of Wolbachia. Wolbachia was found in the thelytokous reproducing species H. femoralis and P. dracaenae. Antibiotic treatment of H. femoralis induced the production of males that copulated with females. The results confirmed Wolbachia to be present in thelytokous reproducing thrips species and proved the presence of the bacterium for the first time in some arrhenotokous reproducing thrips species.

Thysanoptera species recorded in greenhouses in Croatia from 2003–2006

In 2003 the Institute for Plant Protection in Agriculture and Forestry of the Republic of Croatia started a national survey of the possible occurrence of quarantine Thysanoptera species for the EU ( Scirtothrips spp., Thrips palmi Karny) in greenhouses in Croatia. The survey was continued yearly until 2006. This project involved the most important producers of vegetables and flowers in greenhouses and importers of pot plants and cut flowers. Eventual presence of especially T. palmi was checked in glasshouses and plastic greenhouses at 45 localities in 12 continental and 5 Mediterranean counties of Croatia. A total of 26 Thysanoptera species were recorded in the greenhouses, of which 14 species were collected from plant material, 13 were from blue sticky boards and 17 were from yellow sticky boards. Compared to the latest check list of Thysanoptera in Croatia, the following species were recorded for the first time for the country: Echinothrips americanus, Hercinothrips femoralis, Parthenothrips dracaenae and Thrips simplex . The survey did not establish the presence of EU quarantine Thysanoptera.

The First Record of Echinothrips americanus Morgan in Slovenia

In 2001 Echinothrips americanus Morgan was first recorded in Slovenia. The thrips was first recorded in Europe in 1989, but did not begin to spread to a greater extend until 1993. This polyphagous pest is believed to cause direct damage, especially on the leaves of its host plants. The present contribution describes genetic structure of Echinothrips americanus Morgan rooting in polymorphism of the ITS1-5,8S-ITS2 region of the ribosomal DNA. Echinothrips americanus Morgan is less resistant to insecticides and its ability to inhabit new areas is smaller, compared to the Western flower thrips [Frankliniella occidentalis (Pergande)]. It can be concluded that its economic importance in the future will not reach that of the latter. We gave a detailed description of the species, its geographic distribution, and deal with its host plants as well as bionomics and its potential natural enemies.

The aquatic thrips Organothrips indicus Bhatti (Thysanoptera: Thripidae) in Queensland, and a new species, O. wrighti, from tropical Australia

AbstractThe genus Organothrips includes the only fully aquatic thrips, the two previously known species breeding under water in the surface mucous of several unrelated monocotyledonous plants. Organothrips indicus Bhatti is recorded in Australia for the first time, breeding on water hyacinth (Eichhornia crassipes) in a greenhouse near Brisbane. Structural variation within this population is discussed, and character states considered for distinguishing this species from the Pacific taro thrips, O. bianchii Hood. A new species, Organothrips wrighti, is described from Melville Island, Northern Territory and from Cape Tribulation, Queensland. This species has fully macropterous males and is probably not aquatic. The studies on Eichhornia also gave rise to two new distribution records; Salpingothrips aimotofus Kudo is newly recorded from Australia, and the Northern Hemisphere pest thripid Echinothrips americanus Morgan is newly recorded from Thailand.