Mating aggregations and mating success in the flower thrips, Frankliniella schultzei (Thysanoptera: Thripidae), and a possible role for pheromones

Aggregations of Frankliniella schultzei males were observed on the corollas of Hibiscus rosasinensis and Gossypium hirsutum flowers in southeast Queensland. Aggregations were seen only on the upper surfaces of corollas but may have occurred on other flower parts, which were hidden from view. Conspecific females entered aggregations and a small proportion of them mated [18% (n = 163), H. rosasinensis; 30% (n = 181), G. hirsutum]. Most females (87 and 72%, respectively) that did not mate in aggregations walked to other flower parts. Behavior was difficult to observe on these parts, but mating was sometimes observed there. The number of females that landed within aggregations on the upper surfaces of both H. rosasinensis and G. hirsutum corollas was highly correlated with the number of males (r = 0.88, r = 0.93, respectively; P < 0.001). Significantly more mating pairs were observed in high-density aggregations (mean +/- SE, 1.10 +/- 0.22 and 4.44 +/- 0.48, respectively) than in low-density aggregations (0.37 +/- 0.11 and 1.67 +/- 0.29, respectively) (P < 0.05) on flowers of both species. More F. schultzei females were attracted to sticky traps baited with live conspecific males set among flowering Ipomoea indica (mean +/- SE, 8.83 +/- 0.32) and G. hirsutum (10.90 +/- 0.79) plants than to control traps (0.10 +/- 0.05 and 0.70 +/- 0.25, respectively)( P < 0.05), presumably in response to male-produced pheromones. Significantly more females were attracted to traps with high male densities than to traps with low densities. We found no statistical evidence that aggregation size influenced mating success (proportion males that mated). Mating success, however, should be evaluated with respect to mating on all flower parts and not just the upper surfaces of corollas. The results of this study constitute the first behavioral evidence for an attractant sex pheromone in thrips.

The highly rearranged mitochondrial genome of the plague thrips, Thrips imaginis (Insecta : thysanoptera): Convergence of two novel gene boundaries and an extraordinary arrangement of rRNA genes

To help understand the mechanisms of gene rearrangement in the mitochondrial (mt) genomes of hemipteroid insects, we sequenced the mt genome of the plague thrips, Thrips imaginis (Thysanoptera). This genome is circular, 15,407 by long, and has many unusual features, including (1) rRNA genes inverted and distant from one another, (2) an extra gene for tRNA-Ser, (3) a tRNA-Val lacking a D-arm, (4) two pseudo-tRNA genes, (5) duplicate control regions, and (6) translocations and/or inversions of 24 of the 37 genes. The mechanism of rRNA gene transcription in T. imaginis may be different from that of other arthropods since the two rRNA genes have inverted and are distant from one another. Further, the rRNA genes are not adjacent or even close to either of the two control regions. Tandem duplication and deletion is a plausible model for the evolution of duplicate control regions and for the gene translocations, but intramitochondrial recombination may account for the gene inversions in T. imaginis. All the 18 genes between control regions #1 and #2 have translocated and/or inverted, whereas only six of the 20 genes outside this region have translocated and/or inverted. Moreover, the extra tRNA gene and the two pseudo-tRNA genes are either in this region or immediately adjacent to one of the control regions. These observations suggest that tandem duplication and deletion may be facilitated by the duplicate control regions and may have occurred a number of times in the lineage leading to T. imaginis. T. imaginis shares two novel gene boundaries with a lepidopsocid species from another order of hemipteroid insects, the Psocoptera. The evidence available suggests that these shared gene boundaries evolved by convergence and thus are not informative for the interordinal phylogeny of hemipteroid insects. We discuss the potential of hemipteroid insects as a model system for studies of the evolution of animal rut genomes and outline some fundamental questions that may be addressed with this system.

Two new fossil thrips from Baltic amber (Thysanoptera ; Terebrantia) / Lewis J. Stannard.

v.34:no.40(1956)

Thysanoptera: plantas visitadas e hospedeiras no Parque Estadual de Itapuã, Viamão, RS, Brasil

O conhecimento científico sobre a associação de Thysanoptera com plantas nativas ou cultivadas na região Neotropical é praticamente inexistente. Este trabalho objetivou identificar as espécies de tripes e as plantas por eles visitadas ou utilizadas como hospedeiras em uma unidade de conservação, o Parque Estadual de Itapuã (30°22'S 51°02'W), Viamão, Rio Grande do Sul, Brasil. Entre junho de 1999 e maio de 2001, ramos (n=1.274), flores (n=774) e touceiras de gramíneas (n=596) foram sistematicamente amostradas em 20 pontos em quatro transectos estandardizados. O total de 72 espécies de plantas pertencentes a 26 famílias foram identificadas, 60 das quais foram registradas como hospedeiras. Do total de 9.602 espécimes de tripes, 4.900 (50%) foram registrados em flores, 3.764 (39%) em ramos e 938 (10%) nas touceiras de gramíneas. Para 6.533 dos espécimes (4.480 imaturos e 2.053 adultos), foi possível identificar a planta na qual foram coletados. De uma riqueza total de 61 espécies de tripes, 35 foram registradas em flores, 36 em ramos e 14 em touceiras de gramíneas. As espécies de tripes mais abundantes e as plantas que apresentaram a mais alta diversidade de tripes são comentadas.

Una nueva especie de Adraneothrips (Thysanoptera, Tubulifera, Phlaeothripidae)

En este trabajo se describe una nueva especie de thrips de suelo para Adraneothrips Hood, 1925 de Costa Rica. Se provee una clave de identificación para las especies de América Central.

Evolution of asexuality via different mechanisms in grass thrips (thysanoptera: Aptinothrips).

Asexual lineages can derive from sexual ancestors via different mechanisms and at variable rates, which affects the diversity of the asexual population and thereby its ecological success. We investigated the variation and evolution of reproductive systems in Aptinothrips, a genus of grass thrips comprising four species. Extensive population surveys and breeding experiments indicated sexual reproduction in A. elegans, asexuality in A. stylifer and A. karnyi, and both sexual and asexual lineages in A. rufus. Asexuality in A. stylifer and A. rufus coincides with a worldwide distribution, with sexual A. rufus lineages confined to a limited area. Inference of molecular phylogenies and antibiotic treatment revealed different causes of asexuality in different species. Asexuality in A. stylifer and A. karnyi has most likely genetic causes, while it is induced by endosymbionts in A. rufus. Endosymbiont-community characterization revealed presence of Wolbachia, and lack of other bacteria known to manipulate host reproduction. However, only 69% asexual A. rufus females are Wolbachia-infected, indicating that either an undescribed endosymbiont causes asexuality in this species or that Wolbachia was lost in several lineages that remained asexual. These results open new perspectives for studies on the maintenance of mixed sexual and asexual reproduction in natural populations.

Biologia e tabela de vida de fertilidade de Frankliniella occidentalis (Pergande) (Thysanoptera, Thripidae) em morangueiro

O objetivo deste trabalho foi estudar aspectos biológicos de Frankliniella occidentalis (Pergande) (Thysanoptera, Thripidae), considerando que no Brasil quase nada se sabe sobre a fauna de tripes associada à cultura do morangueiro. Larvas recém-eclodidas foram individualizadas em placas de Petri contendo uma flor ou um folíolo de morangueiro, mantidas em câmaras climatizadas (25 ± 1 ºC; 60 ± 10% U.R.; fotofase de 12 horas) e observadas diariamente até a morte. A duração média do período de larva-adulto e a viabilidade não diferiram entre os insetos mantidos em flores (8,49 ± 0,18 e 68,52%) e folíolos (8,85 ± 0,15 e 75,47%). A fecundidade média diária e a total foram mais elevadas quando flores foram fornecidas como alimento (7,4 ± 0,69 e 70,0 ± 9,18 ovos/fêmea respectivamente), em comparação com folíolos (2,4 ± 0,35 e 8,5 ± 1,13 ovos/fêmea, respectivamente). A duração média, em dias, do período embrionário foi distinta entre os indivíduos mantidos em flores (3,7 ± 0,03) e em folíolos (4,4 ± 0,09). A viabilidade dos ovos depositados sobre flores e folíolos foi de 65,5 ± 0,01 e 74,3 ± 0,03%, respectivamente. Com base na tabela de vida de fertilidade, o desempenho dos indivíduos de F. occidentalis que se desenvolveram em flores foi melhor, com uma geração (ovo-adulto) completada a cada 20,92 dias, a 25 °C.

Thrips species (Thysanoptera, Terebrantia) inhabiting irrigated rice and surrounding habitats in Cachoeirinha, state of Rio Grande do Sul, Brazil

In Brazil, almost nothing is known about the thrips fauna associated with rice crops. This is especially true for Rio Grande do Sul State (RS), the major rice producer in Brazil, where no systematic surveys have been conducted. Thus, this work records preliminarily the species of suborder Terebrantia inhabitanting irrigated rice (RC) and three nearby habitats: the area selected for rice, before cultivation (BR), grassland (GR) and forest border (FB) in Cachoeirinha, RS (50º58'21"W; 29º55'30"S). Eight field trips were carried out between October/2004 and February/2005 to Estação Experimental do Arroz in Cachoeirinha. Thrips specimens were collected with sweeping net and transported to laboratory for identification. A total of 623 adults terebrantians were recorded, belonging to two families and 18 species. Frankliniella rodeos (55.5%), Neohydatothrips cf. paraensis (30.3%) and Frankliniella schultzei (5.6%), were the most abundant, comprising more than 90% of the individuals. FB showed the highest species richness (S=15), followed by GR (S=10), RC (S=9) and BR (S=6). FB presented a low number of individuals (14.0%), contrasting with GR (44.8%) and BR (36.7%). In general, thrips abundance in RC was low at EEA (4.5%), and few species seems to effectively use rice as a host-plant. Two species previously considered of economic importance were found, F. rodeos and F. schultzei, the latter a new record for rice in Brazil. Five species are new records to RS.

Species of thrips (Insecta, Thysanoptera) in two strawberry production systems in Rio Grande do Sul State, Brazil

Species of thrips (Insecta, Thysanoptera) in two strawberry production systems in Rio Grande do Sul, Brazil. Thrips are tiny insects responsible for the reduction of strawberry fruit quality. The work aimed to record and quantify the thysanopterofauna present in two strawberry production systems, low tunnel and semi-hydroponic. Leaves, flowers and fruits were collected weekly, from July 2005 to December 2006 in Caxias do Sul and Bom Princípio municipalities, RS. A total of 664 individuals were collected, representing two families, four genus and 10 species: Frankliniella occidentalis (Pergande, 1895), F. schultzei (Trybom, 1910), F. rodeos Moulton, 1933, F. simplex (Priesner, 1924), F. williamsi (Hood, 1915), F. gemina (Bagnall, 1919), Frankliniella sp., Thrips tabaci (Lindeman, 1888), Thrips tabaci (Lindeman, 1888), Caliothrips fasciatus (Pergande 1895) from Thripidae and Heterothrips sp. from Heterothripidae. Frankliniella occidentalis represented 89.7% of the samples with 95.8% of the species collected in flowers, 3.9% in fruits and 0.8% in leaves. The results show that flowers are the most important food resource for these insects on strawberry plants. Frankliniella rodeos, F. simplex, F. williamsi, C. fasciatus, and Heterothrips sp. are new records on strawberry for Brazil.

Occurrence and damages of Danothrips trifasciatus (Thysanoptera, Thripidae) on Calophyllum brasiliense (Clusiaceae) in Brazil

Occurrence and damages of Danothrips trifasciatus (Thysanoptera: Thripidae) on Calophyllum brasiliense (Clusiaceae) in Brazil. Danothrips trifasciatus Sakimura, 1975 (Thysanoptera, Thripidae) is recorded for the first time in Brazil, in the municipality of Garça, São Paulo state. Individuals were collected in April 2011 damaging young leaves of guanandi, Calophyllum brasiliense Cambess. (Clusiaceae), forest species of increasing importance in Brazil. Future studies involving aspects on biology and population dynamics of the thrips in this plant species need to be carried out, in order to establish its potential economic importance to guanandi.

Propuesta de muestreo para Neohydatothrips signifer (Thysanoptera: Thripidae) en el cultivo de maracuyá

El objetivo de este trabajo fue desarrollar una propuesta de muestreo de Neohydatothrips signifer en el cultivo de maracuyá. Se correlacionó la infestación promedio del trips en el cultivo con las variables meteorológicas de humedad relativa, temperatura y precipitación, con uso del coeficiente de correlación de Pearson. Así mismo, se determinó el índice de agregación de la población en el cultivo, con la prueba chi cuadrado (X²) para la distribución de Poisson, la prueba de la razón V²/µ, y la distribución de la binomial negativa. La única variable climática que se correlacionó significativamente con la densidad promedio del trips fue la temperatura. Se presentó mayor incidencia y densidad poblacional del insecto en los terminales vegetativos en comparación con los botones florales. El patrón de disposición espacial que se presentó en todos los estados de desarrollo fenológico del cultivo fue de tipo agregado. Con el índice de agregación y el tamaño promedio de la población, se calculó que se deben muestrear 22 terminales nuevos por hectárea, sin importar su posición en la planta. El muestreo del trips en el cultivo de maracuyá debe hacerse sobre los terminales vegetativos de la planta, sin importar la posición del terminal en ella.

Percevejos predadores (Orius spp.) (Hemiptera: Anthocoridade) e tripes (Thysanoptera): interação no mesmo habitat?

O gênero Orius Wolff é composto por espécies de percevejos predadores, principalmente de tripes, encontradas em muitos ecossistemas naturais e manejados. Entretanto, as interações que podem ocorrer entre esses predadores e suas presas no mesmo "habitat" não são bem conhecidas entre as espécies das regiões tropicais. Este estudo teve como objetivo registrar a interação de espécies de Orius e de tripes coletadas na mesma planta, ou seja, presentes no mesmo "habitat". As coletas foram feitas em várias plantas cultivadas, no campo e em casas de vegetação e em plantas invasoras. A forma e o grau de associação entre as espécies foram determinados, utilizando-se o coeficiente de Spearman (R), calculado com dados de presença/ausência das espécies (Orius e tripes) no mesmo "habitat". Orius insidiosus (Say) foi encontrado associado positivamente aos tripes Frankliniella sp., Neohydatothrips sp. e Haplothrips gowdeyi (Franklin) e negativamente associado a Frankliniella schultzei (Trybom) e Caliothrips phaseoli (Hood). Orius thyestes Herring e Orius sp1 ocorreram simultaneamente em 10 espécies de tripes sem, contudo, apresentar associação significativa, enquanto Orius perpunctatus (Reuter) esteve associado positivamente às espécies Frankliniella sp. e Neohydatothrips sp. e, negativamente, a Frankliniella gemina (Moulton).

Ocorrência de Frankliniella schultzei (trybom) (thysanoptera: thripidae) em plantas daninhas

Realizaram-se levantamentos de plantas daninhas, no Campus da UNESP em Jaboticabal/SP, com o objetivo de identificar espécies de plantas daninhas hospedeiras do tripes Frankliniella schultzei (Trybom). As plantas foram coletadas semanalmente utilizando-se o método de ensacamento. A separação dos tripes foi feita mediante emprego do funil de Berlese. Entre as 43 espécies de plantas daninhas encontradas nas áreas amostradas, 19 são hospedeiras do tripes. Rabanete (Raphanus sativus L.), nabiça (R. raphanistrum L.) e mostarda (Sinapsis arvensis L.) foram as que apresentaram as maiores porcentagens de F. schultzei, 45, 27 e 17% do total de fêmeas coletadas respectivamente.