Anaphothrips Obscurus Research Articles

The extraordinary rearrangement of mitochondrial genome of the wheat pest, Aptinothrips stylifer and the mitochondrial phylogeny of Thripidae (Thysanoptera).

The mitochondrial gene order in Thysanoptera is notably distinct and highly rearranged, with each species exhibiting its own unique arrangement. To elucidate the relationship between gene rearrangements and phylogeny, the complete mitochondrial genome (mitogenome) of the wheat pest, Aptinothrips stylifer, was sequenced and assembled, spanning a total length of 16,033 bp. Compared with the ancestral arthropod mitogenome, significant rearrangement differences were evident in A. stylifer, whereas the gene order between A. stylifer and Anaphothrips obscurus was similar. Phylogenetic trees were reconstructed based on all 13 protein-coding gene sequences using Bayesian inference and maximum-likelihood methods, both yielding similar topological structures. Notably, A. stylifer was robustly clustered with A. obscurus, affirming its classification within Anaphothrips genus group. This exemplifies the potential correlation between gene rearrangements and phylogeny in the Thripidae family. Additionally, the mitogenome of A. stylifer exhibited several atypical features, including: (1) Three putative control regions (CRs)in close proximity, with CR2 and CR3 displaying partial similarity, and CR1 differing in base composition; (2) Two transfer RNAs (tRNAs),trnS1 and trnV, lacking the DHU arm; (3) Two ribosomal RNA (rRNA)genes inverted and positioned distant from each other; (4) Negative AT and GC skew (ATskew = -0.001, GC skew = -0.077); (5) One transposition (nad6), one inverse transposition (trnQ), four inversions (trnF, trnH, trnC, and gene block nad1-trnL1-rrnL-trnV-rrnS), and four tandem duplication random loss events; and (6) Two protein-coding genes, nad2 and atp8, terminated with an incomplete stop codon "T".

Anaphothrips obscurus (grass thrips)

Anaphothrips obscurus (grass thrips)

Efficacy of binary combinations between methyl salicylate and carvacrol against thrips Anaphothrips obscurus: laboratory and field trials.

Thrips Anaphothrips obscurus are one of the cosmopolitan major pests feeding on cereals and other grasses. In order to develop alternatives of chemical insecticides for thrips control, based on fumigant activity screening and evaluation of 22 essential oil (EO) compounds against the thrips, the binary interactions of methyl salicylate and carvacrol (MS-C) with high fumigant toxicity were studied systematically by bioassay and field trials. The bioassay results showed that six in 22 EO compounds had high fumigant toxicity against both the second-instar nymphs and adults of A. obscurus, including methyl salicylate, carvacrol, thymol, trans-cinnamaldehyde, diallyl trisulfide, and L-perillaldehyde. Furthermore, the combination of methyl salicylate mixed with carvacrol at a volume ratio of 5:5 exhibited the most significant synergism against A. obscurus, with a poison ratio value of 1.32 and a co-toxicity coefficient of 151.15. The optimal formulation of microemulsion (ME) was composed of 5% methyl salicylate, 5% carvacrol, 46% adjuvant and 44% deionized water. The result of dynamic light scattering and stability showed that MS-C 10% ME was a transparent, single-phase and homogeneous liquid system. Field trials indicated that the ME displayed a significant control efficacy of about 89.17% on thrips in peppers, and 82.59% in broad bean on the seventh day post application with a dosage of 600.0 g A.I hm-2 , respectively. The binary combination of MS-C possesses strikingly synergistic action against thrips A. obscurus, and the MS-C 10% ME has the potential to be developed as a botanical pesticide product for thrips control. © 2019 Society of Chemical Industry.

일천궁과 토천궁에서 발생하는 총채벌레류의 분자동정

Background: Cnidium officinale Makino and Ligusticum chuanxiong Hort. are important medicinal crops in Korea. However, there is insufficient information on the identification of thrips, which attack these plants. Until now, one species of thrips has been recorded as a main pest.<BR> Methods and Results: To identify the thrips emerging in C. officinale Makino and L. chuanxiong Hort., these plants were independently cultivated in two local areas. Thirty individuals of each plant species were selected randomly and surveyed for the presence of thrips. After confirming the existence of thrips, 100 thrips individuals were collected from each crop using the beating method. To identify thrips species, we performed PCR-restriction fragment length polymorphism (RFLP)-based analysis using ITS2 primer sets. Six thrips species were identified: western flower thrips (Frankliniella occidentalis), flower thrips (F. intonsa), onion thrips (Thrips tabaci), chrysanthemum thrips (T. nigropilosus), chilli thrips (Scirtothrips dorsalis), and grass thrips (Anaphothrips obscurus). The proportion of these species differed between the host plant species.<BR> Conclusions: Six thrips species were major pests of two medicinal crops. Integrated pest management is required to control these thrips species, and will enhance the yield and quality of C. officinale and L. chuanxiong.

When the ground cover brings guests: is Anaphothrips obscurus a friend or a foe for the biological control of Tetranychus urticae in clementines?

Biological control of Tetranychus urticae Koch (Acari: Tetranychidae), a key pest of clementines, can be improved in this crop with the establishment of a ground cover of Festuca arundinacea Schreber (Poaceae). This cover houses an abundant and diverse community of predatory Phytoseiidae mites including Euseius stipulatus (Athias-Henriot), Neoseiulus barkeri Hughes, Neoseiulus californicus (McGregor) and Phytoseiulus persimilis Athias-Henriot and a dense population of the grass thrips Anaphothrips obscurus Muller (Thysanoptera: Thripidae) throughout the year. The aim of this study was to determine whether the presence of this thrips species could be related to the improvement in the biological control of T. urticae. Therefore, the capacity of the abovementioned phytoseiids to feed and reproduce on A. obscurus and their feeding preferences when T. urticae and A. obscurus were simultaneously offered, were analyzed. The results show that E. stipulatus, N. barkeri and N. californicus have a type II functional response when offered A. obscurus nymphs, whereas P. persimilis barely feeds on this thrips species. Furthermore, N. barkeri and N. californicus can reproduce feeding only on thrips. Regarding prey preference, the Tetranychus spp.-specialist P. persimilis preferably preyed on T. urticae, the generalists N. barkeri and E. stipulatus preferred A. obscurus, and the selective predator of tetranychid mites N. californicus showed no preference. Therefore, we hypothesize that the enhanced biological control of T. urticae observed could be related to A. obscurus becoming an alternative prey for non-specialist phytoseiids, without altering the control exerted by the T. urticae-specialist P. persimilis and likely reducing intraguild predation.

Novel insights into mitochondrial gene rearrangement in thrips (Insecta: Thysanoptera) from the grass thrips, Anaphothrips obscurus

We sequenced the mitochondrial (mt) genome of the grass thrips, Anaphothrips obscurus, which is highly rearranged and differs from the four thrips species reported previously in the arrangement of both tRNA genes and a protein-coding gene, nad3, and in the copy number of the control region (CR). We reconstructed the phylogeny of the thrips with mt genome sequences, and used it as a framework to gain insights into mt genome evolution in thrips. It is evident that A. obscurus is less rearranged in mt genome organization than the other four known thrips. nad3 is in its ancestral location in A. obscurus but was translocated in other four thrips. Also, A. obscurus has one CR, which is ancestral to hexapods whereas other thrips have two or three CRs. All of the five thrips whose mt genomes have been sequenced to date are from the subfamily Thripinae, which represents about a quarter of the species richness in the order Thysanoptera. The high variation in mt genome organization observed in a subfamily challenges our knowledge about animal mt genomes. It remains to be investigated why mt genomes evolved so fast in the subfamily Thripinae and how mt genomes evolved in other lineages of thrips.

Ecobiology of Anaphothrips obscurus, a new dweller of citrus orchards brought in by more sustainable pest management practices

Abstract The abundance and frequency of Anaphothrips obscurus (Thysanoptera: Thripidae) increased in a cover of Festuca arundinacea (Poaceae) when this plant was used to improve the biological control of the clementine key pest Tetranychus urticae (Acari: Tetranychidae). To unveil the ecological role of A. obscurus in this system, we re‐explored field data and performed laboratory studies aiming to determine its demographic parameters and feeding habits, as well as its role as a prey of predatory mites (Acari: Phytoseiidae) occurring in the Spanish citrus agreoecosystem. Field studies indicate that T. urticae populations decreased, whereas those of A. obscurus and phytoseiids, as a whole, increased. Reproductive and demographic parameters of macropterous and brachypterous morphs of A. obscurus were different and confirmed the host status of F. arundinacea. Anaphothrips obscurus could compete with T. urticae as a result of its higher intrinsic rate of increase in F. arundinacea. However, A. obscurus zoophagy on T. urticae eggs and the host status of citrus can be discarded. Anaphothrips obscurus can be a prey for Euseius stipulatus, Neoseiulus barkeri and Neoseiulus californicus (three phytoseiids preying on T. urticae), suggesting that apparent competition between A. obscurus and T. urticae could occur in citrus orchards.

Effects of temperature on the development, reproduction and population growth of Anaphothrips obscurus (Thysanoptera: Thripidae)

Anaphothrips obscurus is a cosmopolitan pest feeding on cereals and other grasses. The effects of constant temperatures on the biology of A. obscurus are not well known. Laboratory studies were conducted to assess the effects of temperature on the development, survival, longevity, fecundity and population parameter of A. obscurus at six constant temperatures (15, 20, 25, 30, 32, 35°C). The hatchability was the lowest at 15°C, the highest at 25°C and no eggs hatched at 35°C. Developmental rates increased linearly as the temperature increased. The lower developmental threshold temperature was 10.6°C and 200 degree-days were required to complete development from egg to adult. Adult longevity decreased with increasing temperature, and ranged from 68.87 d at 15°C to 16.41 d at 32°C. The highest total fecundity occurred at 20°C with 162 eggs per female. The temperature-dependent total fecundity, age-specific oviposition rate, and age-specific survival rate models were described. The intrinsic rate of increase (rm) was significantly higher at 30 and 32°C (0.239 and 0.250) than at other temperatures. This study suggests that optimal developmental and reproductive temperatures for A. obscurus ranges between 25 and 30°C and this may help this species adapt to warmer areas and widen its distribution and potential for damage in response to global warming. These findings will also be useful in developing monitoring programs, population dynamic models, and timing of control measures for A. obscurus.

Comparison of developmental and reproductive biology in wing diphenic Anaphothrips obscurus (Thysanoptera: Thripidae)

Anaphothrips obscurus (Müller) is a cosmopolitan pest feeding on cereal crops and grasses. This species exhibits wing polyphenism. Differences in the life history traits of female macropterous and brachypterous A. obscurus were compared in the laboratory for this study. Experiments were performed in climate chambers set at 20 and 25±1°C, 60±10% RH under a 16L:8D photoperiod. The duration of total pre-adult stage, adult pre-oviposition period and total pre-oviposition period of macropterous morphs were significantly longer than in the brachypterous morphs both at 20 and 25°C. No significant differences were found in adult longevity, survival rate or total fecundity between the two wing morphs, while early fecundity was significantly higher for brachypterous females compared with that for macropterous females at two temperatures.

Spatial Dependence, Dispersion, and Sequential Sampling ofAnaphothrips obscurus(Thysanoptera: Thripidae) in Timothy

The spatial distribution and dispersion of Anaphothrips obscurus (Müller) (Thysanoptera: Thripidae) was examined with the goal of establishing a sequential sampling plan for this pest in timothy, Phleum pratense L. (Poaceae). Approximately 16 different California timothy fields were sampled twice yearly from 2006 to 2008 using direct observation and the beat cup method. For direct observation, the number of thrips on each leaf of the plant was counted. For the beat cup method, tillers were tapped into a cup and dislodged thrips were counted. Samples were separated by ≈3 m in 2006 and 2007 and exactly 3 m in 2008. Spatial autocorrelation of intrafield population distribution was tested for significance in 2008 using Moran's I, but autocorrelation was not detected. The population dispersion was assessed by Taylor's power law and was determined to be aggregated and density-dependent. Intraplant population dispersion and distribution for each year were also evaluated for adults, larvae, and total thrips. All lifestages were highly spatially dependent and more thrips were found near the top of the plant than the bottom. Direct observation proved to be a more accurate and precise method than the beat cup method, especially when thrips abundances were greater than one. However, the number of samples required to provide an accurate level of precision was unrealistic for both methods. A sequential sampling plan was evaluated, but was not practical for the beat cup method because few thrips were found using this method. Because there was no spatial autocorrelation at sampling distances of 3 m, samples can be taken at intervals at 3 m to obtain spatially independent population abundance estimates.

Grass Thrips (Anaphothrips obscurus) (Thysanoptera: Thripidae) Population Dynamics and Sampling Method Comparison in Timothy

Sampling studies were conducted on grass thrips, Anaphothrips obscurus (Müller) (Thysanoptera: Thripidae), in timothy, Phleum pratense L. These studies were used to compare the occurrence of brachypterous and macropterous thrips across sampling methods, seasons, and time of day. Information about the population dynamics of this thrips was also revealed. Three absolute and two relative methods were tested at three different dates within a season and three different daily times during four harvest periods. Thrips were counted and different phenotypes were recorded from one of the absolute methods. Absolute methods were the most similar to one another over time of day and within seasonal dates. Relative methods varied in assessing thrips population dynamics over time of day and within seasonal dates. Based on thrips collected from the plant and sticky card counts, macropterous individuals increased in the spring and summer. Thrips aerially dispersed in the summer. An absolute method, the beat cup method (rapping timothy inside a plastic cup), was among the least variable sampling methods and was faster than direct observations. These findings parallel other studies, documenting the commonality of diel and diurnal effects on sampled arthropod abundance and the seasonal effects on population abundance and structure. These studies also demonstrate that estimated population abundance can be markedly affected by temporal patterns as well as shifting adult phenotypes.

First description of the male of the wheat thrips, Anaphothrips obscurus (Thysanoptera: Thripidae)

Anaphothrips obscurus (Müller), a common pest on the leaves of cereal crops (Ananthakrishnan, 1984), lives on grasses in many parts of the world. However, males of this species have remained unknown, together with the males of 12 more of the 79 species recorded worldwide in the genus Anaphothrips Uzel (Thysanoptera: Thripidae). In the west and northwest of Iran during 2008–2009 we found males of A. obscurus on rice and wheat crops, and this sex is here described and illustrated for the first time.

Plant Quality and Conspecific Density Effects onAnaphothrips obscurus(Thysanoptera: Thripidae) Wing Diphenism and Population Ecology

Factors that influence thysanopteran wing diphenism are not well known. In these studies, the impact of food quality, mediated through nitrogen addition, and conspecific density was explored on the wing diphenism of an herbivorous thrips species (Anaphothrips obscurus Müller) (Thysanoptera: Thripidae). In the first study, nitrogen was added to timothy grass (Phleum pretense L.) (Poales: Poaceae) transplants, and naturally occurring thrips populations were caged on the plants. Thrips abundance and foliar nutrients were assessed every 2 wk. A separate factorial experiment in growth chambers explored the impact of both plant nitrogen addition and thrips abundance on wing diphenism. Thrips density was manipulated by adding either 3 or 40 thrips to potted and caged timothy. Thrips abundance and foliar nutrients were measured 58 d after treatment placement. Plant quality directly affected thrips wing diphenism independent of thrips density in both experiments. Near the end of the field cage experiment, density may have indirectly impacted wing diphenism. In both experiments, plant quality and thrips density interacted to affect thrips population abundance. Plant quality alone can affect thrips wing diphenism, but it remains unclear whether density alone can affect thrips wing diphenism. This is a unique and understudied system that will be useful to examine generalized theories on the negative interaction between reproduction and dispersal.

Commonly Intercepted Thrips at U.S. Ports-of-Entry from Africa, Europe, and the Mediterranean. IV. Miscellaneous Thripine Genera Excluding Frankliniella, Iridothrips, and Thrips (Thysanoptera: Thripidae)

Abstract A total of 130 species of thrips occurring in Africa, Europe, and the Mediterranean region were intercepted by U.S. agricultural quarantine officers from shipments of cut flowers and other plants at various ports-of-entry in the United States from 1983 to 1999. This is Part 4 of a guide to the identification of thrips coming into this country from these regions: it uses keys, line drawings, and scanning electron micrographs to identify 51 species in 36 miscellaneous thripid genera not covered in Parts 2 and 3. Of the 321 records identifiable to species, 70% of the interceptions were attributed to ten species: Odontothrips karnyi Priesner clearly was most commonly intercepted, with substantially smaller percentages attributed to Limothrips cerealium (Haliday), Anaphothrips obscurus (Muller), Neohydatothrips samayunkur (Kudo), Limothrips denticornis (Haliday), Synaptothrips distinctus (Bagnall), Tenothrips discolor (Karny), Ceratothripoides brunneus Bagnall, Ceratothrips ericae (Haliday), and Mycte...

Thrips species associated with soybean in Hungary

The most dangerous pests of soy beans are mites and thrips, which is the reason why the present paper aims to examine the changes in their numbers and to investigate dominance relationships of them on some varieties of different maturity groups. In 1998–2000, small plot experiments were conducted atMosonmagyarovar in the Kisalfold region with the following soybean varieties: early ripening ‘Bolyi 38’, ‘Evans’, ‘McCall’, middle ripening ‘Bolyi 45’ and late ripening ‘Eszter’, ‘Zsuzsanna’ and ‘Borza’. Mites and thrips were collected every week with a Berlese-extractor. It was observed that Thrips tabaci was the dominant thrips species on soybean leaves, but Frankliniella intonsa was dominant in the flowers. Only a few representatives of Anaphothrips obscurus and Thrips angusticeps were found. Among the predatory thrips Aeolothrips intermedius and Scolothrips longicornis were present in greater numbers. However, their number was not enough to reduce the number of phytophagous thrips. Besides the dominant T. t...

Species composition of Thysanoptera in white cabbage heads

In 2000-2002 thrips species were collected from mature white cabbage head leaves in Hungary. The total number of the sampled specimens was 4226. Out of the 3374 identified adults Thrips tabaci was predominant (91.3%). Frankliniella tenuicornis was found in significant number (6.9%) with rather extraordinary appearance in 2000 (15.1%) but in the other years its frequency was lower (0.5%, 1.9% respectively). The rest of the adults (1.8%) were: Frankliniella intonsa, Aeolothrips intermedius, Thrips angusticeps, Thrips atratus, Haplothrips aculeatus, Limothrips denticornis, Anaphothrips obscurus, Chirothrips manicatus and Scolothrips longicornis. The 852 second instar larvae were also identified. 96.4% was Thrips tabaci, 2.7% Thrips angusticeps and 0.8% Anaphothrips obscurus. In spite of the fact that in 2000 15.1% of the adults on cabbage was Frankliniella tenuicornis, not a single larva was found. Therefore we concluded that in Hungary it is only the thelytokous populations of Thrips tabaci that are of high importance as thrips pest of white cabbage.

Tritrophic Interactions of TransgenicBacillus thuringiensisCorn,Anaphothrips obscurus(Thysanoptera: Thripidae), and the PredatorOrius majusculus(Heteroptera: Anthocoridae)

Laboratory feeding experiments using transgenic Bacillus thuringiensis variety kurstaki (Berliner) corn plants were carried out to study the effects of B. thuringiensis-fed herbivorous prey on the predator Orius majusculus (Reuter). Host plants were a transgenic B. thuringiensis-expressing (Cry1Ab) corn hybrid and the corresponding untransformed isogenic B. thuringiensis-free corn hybrid. The herbivorous prey species used in the experiment was Anaphothrips obscurus (Muller), a thysanopteran pest of corn, not sensitive to Cry1Ab toxin. The objectives were to quantify the effects of B. thuringiensis-fed prey on the development and mortality of immature O. majusculus. There was no significant difference in total mean mortality from hatch to adult eclosion between O. majusculus nymphs reared on B. thuringiensis-fed or B. thuringiensis-free prey. Similarly, no significant differences in total developmental time of O. majusculus was detected when reared on the two different prey types. Overall mortality was low, confirming that the methodology used was appropriate. We propose this approach as an efficient standardized preregistrational testing for side effects of transgenic plants on small predators such as Orius spp.

Seasonality of Predaceous Plant Bugs (Heteroptera: Miridae) and Phytophagous Thrips (Thysanoptera: Thripidae) as Influenced by Host Plant Phenology of Native Azaleas (Ericales: Ericaceae)

Seasonal synchrony of phytophagous insects, especially Heterothrips azaleae Hood, and the predaceous mirids Dicyphus rhododendri Dolling and Rhinocapsus vanduzeei Uhler, was determined on five species of native deciduous azaleas ( Rhododendron spp.) during 1990–1993. Florida, Alabama, Piedmont, and Flame azaleas supported populations of H. azaleae ; Plumleaf azalea did not. Peak adult and larval activity of this species of thrips varied with sequence of flowering during April and May. While R. vanduzeei was present on all azalea species, except Plumleaf, D. rhododendri was found to be abundant only on Florida azalea and occurred more rarely on Alabama azalea. Dicyphus rhododendri nymphs emerged in late March or early April, 2–3 wk before R. vanduzeei nymphs emerged from overwintering eggs, which were inserted into the woody plant tissue. Adult D. rhododendri became scarce after mid-May. Rhinocapsus vanduzeei adults were present until the last week of June. Although both species are known to be pollen feeders, scavengers, or both, they were observed to be active effective predators of thrips and other small insects in the field and in laboratory tests. Additional thrips species collected were Terebrantia: Frankliniella tritici (Fitch), Anaphothrips obscurus (Muller), Chaetanaphothrips orchidii (Moulton), Thrips nigropilosus Uzel, and Tubulifera: Leptothrips mali (Fitch). Seasonal occurrence of additional phytophagous Hymenoptera, Lepidoptera, and Homoptera are given.

Genetics of Resistance in Maize to a Complex of Three Species of Thrips (Thysanoptera: Thripidae)

During summer 1988, a heavy infestation of Thrips, Anaphothrips obscurus (Mueller), Frankliniella fusca (Hinds), and F. tenuicomis (Uzel) occurred on maize, Zea mays L., allowing for evaluation of resistance in 10 inbred maize lines. Thrips populations peaked at the end of June, and evaluations of the damage were taken at this time. Inbred 41:2504B had the smallest thrips population, B37 had the largest population, and Mo17, C103, and B73 were intermediate. A 10-inbred-line diallel cross, based on damage caused by leaf-feeding, showed that variations due to general combining ability (GCA) and specific combining ability (SCA) were highly significant. Variation due to GCA, however, was 14 times greater than that for SCA, indicating that additive genetic effects were more important than nonadditive effects. The inbred 41:2504B was the most resistant and best general combiner, whereas C103 was the most susceptible to thrips damage.

THRIPS (THYSANOPTERA) IN CANOLA CROPS IN SASKATCHEWAN

AbstractAdults of nine species of thrips were collected from canola fields:Aeolothrips fasciatus(L.),Anaphothrips obscurus(Müller),Frankliniella occidentalis(Perg.),Frankliniella tritici(Fitch),Limothrips denticornisHaliday,Odontothrips loti(Haliday),Thripsnr.fuscipennisHaliday,Thrips tabaciLindeman, andThrips vulgatissimusHaliday. Of these,F.triticiwas the most abundant in the collections and appears to have the greatest potential to be a significant canola pest, followed byT.tabaciandT.vulgatissimus.