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Armored Scales and Their Parasitoids on Commercial Avocados Grown in California or Imported from Mexico
Abstract
Levels of armored scales (Hemiptera: Diaspididae) on Mexican Hass avocados imported into California over May 2008–June 2009 were monitored on 135 trucks entering the state via the Blythe border station, the entry point receiving the highest volume of fruit. Levels of live sessile scales were 3.9-fold higher than indicated in a previous survey (September 2007–April 2008) although levels of live eggs and crawlers were similar to previous levels. A survey of avocado fruit in California infested with armored scales detected four species known to be endemic but failed to find any of the seven exotic Diaspididae entering the state on Mexican fruit. Monitoring of Mexican armored scales on imported avocados from September 2007 to December 2010 recovered 10 species of parasitoids predominated by two species of Signiphora Ashmead (Hymenoptera: Signiphoridae). One of these species, Signiphora flavopalliata Ashmead, comprised 36% of all collected Mexican parasitoids and is a known hyperparasitoid. A survey of armored scale parasitoids present on commercial California avocados detected 17 genetic signatures, with only four of these in common with those detected on imported Mexican fruit. The implications of these findings are discussed.
... However, a detailed study of the natural enemies associated with A. tubercularis in Ethiopia, incorporating molecular identification, has not been conducted. In addition to coccinellid predators, parasitic hymenopterans are key natural enemies of armored scales (Morse et al. 2016;Amouroux et al. 2019), and several members of the family Aphelinidae (e.g. Aphytis and Encarsia species) have been implemented successfully in biological control programs for scale management around the world. ...
... Inspections were conducted within 12 h of arrival at the laboratory. Following the same procedure by Morse et al. (2016), under a dissecting microscope, individual scale covers were gently turned over using a sterilized needle, and live sessile A. tubercularis (crawlers, adult male and female) were collected in to 2ml vials (one vial per tree) and preserved in 95 % ethanol. Vials were wrapped tightly with parafilm to prevent the ethanol from evaporating. ...
... The D2 domain of 28S rDNA was again amplified, this time using the primers 28sF3633 and 28sR4076 (5'-AGA CTC CTT GGT CCG TGT TT-3') as described in Rugman-Jones et al. (2010). A second rDNA locus, the internal transcribed spacer 2 (ITS2), was also amplified using the primers, 58SF (5'-GTG AAC TGC AGG ACA CAT GAAC-3') and ITS4 (5'-TCC TCC GCT TAT TGA TAT GC-3') as described in Morse et al. (2016). Both loci are widely utilized in diagnostic and systematic studies of Hymenoptera, and therefore well represented in public sequence databases. ...
White mango scale, Aulacaspis tubercularis Newstead, was first reported in Ethiopia in 2010 from mango orchards belonging to “RAJ Agro Industry Loko Mango Farm”, formerly named as “Green Focus Ethiopia LTD”. White mango scales were monitored for the presence of natural enemies at three study sites in western Oromia and Assosa zone of Benishangul-Gumuze Regional State. Specimens of A. tubercularis, its predators, and its parasitoids were identified via DNA sequencing. DNA sequences of the COI gene of all Ethiopian scales sampled were identical and confirmed as a single haplotype of A. tubercularis. Three predators of A. tubercularis were recovered. These included two Coccinellidae (Coleoptera), Rhizobius lopanthe (Blaisdell) and, a species of Platynaspis, and a third unidentified beetle species from the family Nitidulidae.DNA sequences of the parasitoid specimens identified two species of Encarsia, E. lounsburyi Berlese & Paoli and E. citrina Craw (Hymenoptera: Aphelinidae). These natural enemies were identified for the first time as resident natural enemies of A. tubercularis in Ethiopia. During specimen collection, the newly associated adults and larvae of the predators were found feeding voraciously on live A. tubercularis. The parasitoids were found parasitizing all stages of sessile A. tubercularis. The novel association of resident predators and parasitoid wasps with A. tubercularis has likely developed recently in Ethiopia. Future work will help determine if the resident natural enemy complex can be used for conservation biological control of A. tubercularis, to improve cost-effective pest management of this exotic insect pest in Ethiopia, along with other compatible control options.
... In recent years, DNA sequencing methods have become a useful complementary tool to morphological methods that facilitates an accurate and fast identification of insect species (Gariepy et al., 2014). In this sense, several studies have demonstrated the usefulness of molecular techniques to know the identity and geographic distribution of some Aphytis and Encarsia species (Correa et al., 2016;Morse et al., 2016;Dao et al., 2017;Amouroux et al., 2019). ...
... On the other hand, a segment of the 28S rDNA gene was amplified using the primer pair 28S D-2F (5′-CGTGTTGCTTGATAGTGCAGC-3′) and 28S D-2R (5′-TTGGTCCGTGTTTCAAGACGG-3′) of Campbell et al. (1993). This genomic region has been widely used in diagnostic and systematic studies of Chalcidoidea (Hymenoptera) (Campbell et al., 2000;Babcock et al., 2001;Manzari et al., 2002;Polaszek et al., 2004;Schmidt et al., 2006;Munro et al., 2011;Morse et al., 2016;Fita et al., 2021) and therefore well represented in public sequence databases. In this case, the same reaction mix as above was used but the amplification conditions were as follows: an initial denaturing step of 3 min at 94 • C; followed by 37 cycles of 45 s at 94 • C, 30 s at 55 • C, and 1 min 30 s at 72 • C; and a final extension step of 5 min at 72 • C (Rugman-Jones et al., 2015). ...
The white mango scale (WMS), Aulacaspis tubercularis, is the main pest of mango crops in Southern Spain. Field surveys were carried out from July 2019 to May 2022 to investigate the identity, seasonal abundance and active parasitism rates of A. tubercularis primary parasitoid species, using yellow sticky traps and periodic leaf sampling. The combination of morphological characters and DNA sequences of the mitochondrial cytochrome c oxidase subunit 1 (mtCOI) and 28S ribosomal (28S rDNA) genes allowed the identification of only two parasitoid species belonging to the genus Encarsia Förster (Hymenoptera: Aphelinidae). The most prevalent, E. citrina (Crawford), is a widespread species and proved to be the dominant species in the sampled mango orchards. Next, Encarsia sp., is an unidentified species genetically close to E. lounsburyi Berlese but significantly differs in the sequences of the mtCOI and 28S rDNA regions. Population abundance and active parasitism rates of Encarsia parasitoids depended on the presence of susceptible WMS stages for parasitism and on the abiotic conditions. The seasonal abundance of these parasitoid species fluctuated around the year, being lower during the winter but it increased in late spring, reaching the highest values at the end of summer. The average percentage of active parasitism was 12.48% for female scales and 13.97% for male scales but reached maximum values of 38.56 and 43.52%, respectively at specific seasons in the year. The highest rates of parasitism for female scales were observed in summer, while for male scales were observed in winter. The natural occurrence of parasitoids was unable to control the WMS populations and, consequently, complementary measures should be implemented to reduce its density levels.
... Two regions of nuclear ribosomal RNA were also amplified. The D2 domain of 28S was amplified using the primers 28sF3633 and 28sR4076 as described in Rugman-Jones et al. (2010), and the internal transcribed spacer 2 (ITS2), was amplified using the primers, 58SF (Porter & Collins, 1991) and ITS4 (White et al., 1990) as described in Morse et al. (2016). All reactions were performed in 25 µL volumes on a Mastercycler® ep gradient S thermocycler (Eppendorf North America Inc., New York, New York, USA). ...
... Vol.: (0123456789) of 28 S nuclear ribosomal DNA gene (28 S rDNA) was amplified using the primers 28sF3633 (5'-TAC CGT GAG GGA AAG TTG AAA-3') and 28b (5'-TCG GAA GGA ACC AGC TAC TA-3') (Morse et al., 2009). This genomic region has been widely used in diagnostic and systematic studies of Chalcidoidea (Hymenoptera) (Campbell et al., 2000;Morse et al., 2016;Fita et al., 2021;del Pino et al., 2023) and therefore well represented in public sequence databases. In this case, the thermocycler was programmed for an initial denaturing step of 3 min at 94 °C; followed by 37 cycles of 45 s at 94 °C, 30 s at 55 °C, and 1 min 30 s at 72 °C; and a final extension step of 5 min at 72 °C (Rugman-Jones et al., 2015). ...
The white mango scale, Aulacaspis tubercularis Newstead (Hemiptera: Diaspididae) is an exotic pest that causes important economic damage in the Spanish mango crops. Prospecting for potential natural enemies, the parasitic wasp Arrhenophagus chionaspidis Aurivillius (Hymenoptera: Encyrtidae) was first detected attacking immature male stages of A. tubercularis in Tenerife (Canary Islands, Spain) in 2022. Still, its influence on pest populations was not evaluated. This endoparasitoid was identified by its morphological characteristics and characterized for the first time by DNA barcoding of adult females using partial (651 bp) mitochondrial cytochrome oxidase 1 (mtCOI) gene (Genbank accession number OQ646824). Its potential utilization as biological control agent of A. tubercularis in mango crops is discussed. Therefore, further studies need to be conducted about its biology, population dynamics and rate of natural parasitism for the development of effective biological control strategies of A. tubercularis in mango.
... The polymerase chain reaction (PCR) was used to amplify a section of the mitochondrial cytochrome oxidase subunit 1 gene (COI) and two separate regions of nuclear ribosomal RNA (rRNA); the D2 domain of 28S (28S-D2) and the internal transcribed spacer 2 (ITS2). Amplification utilized the exact same primers and protocols detailed in Triapitsyn et al. (2021Triapitsyn et al. ( , 2023; also see Morse et al., 2016). Amplifications were confirmed by gel electrophoresis and PCR products were purified using a DNA Clean & Concentrator™-5 kit (Zymo Research, Irvine, California, USA). ...
... DNA was extracted from individual wasps using the Chelex method described in Polaszek et al. (2012). The polymerase chain reaction (PCR) was used to amplify the internal transcribed spacer 2 (ITS2) using the primers 58SF (Porter & Collins 1991) and ITS4 (White et al. 1990) as described in Morse et al. (2016). In a separate PCR, the "barcoding" region of the mitochondrial cytochrome c oxidase subunit I gene (COI) was amplified using LCO1490 and HCO2198 (Folmer et al. 1994) as described in Rugman-Jones et al. (2012). ...
New country and host records of Trichogramma species for Turkey are presented. Trichogramma aurosum Sugonjaev & Sorokina is recorded for the first time from Turkey, and a new species, T. zerynthiae Polaszek & Bolu, is described. Morphological identification based on dissected male genitalia is supplemented by molecular sequence data.
http://www.zoobank.org/urn:lsid:zoobank.org:pub:9CFF5E39-F1D2-42FB-86B8FC8475EC3560
... The polymerase chain reaction (PCR) was employed to amplify the "barcoding" region of the mitochondrial cytochrome c oxidase subunit I gene (COI) using the primers C1-J-1718 (5'-GGAGGATTTGGAAATTGATT-AGTTCC-3') and C1-N-2191 (5'-CCCGGTAAAATTA-AAATATAAACTTC-3'; Simon et al. 1994), as described in Rugman-Jones et al. (2012). We also amplified two separate regions of nuclear ribosomal RNA, the D2 region of 28S (28S-D2) and the internal transcribed spacer 2 (ITS2), using primers and protocols described in Rugman-Jones et al. (2010) and Morse et al. (2016), respectively. All three loci have been widely used for investigating species boundaries among insects. ...
A fairyfly (Hymenoptera, Mymaridae) Cleruchus breviclava Triapitsyn & Coray, sp. nov. is described and illustrated. The new species is an egg parasitoid of the invasive Cis chinensis Lawrence (Coleoptera, Ciidae) in Antrodia xantha fungus (Polyporales, Fomitopsidaceae) in Basel, Switzerland; it is also known from low mountains in Germany and Switzerland. Supporting data on the “barcoding” region of the mitochondrial cytochrome c oxidase subunit I gene, as well as separate regions of nuclear ribosomal RNA, the D2 region of 28S and the internal transcribed spacer 2, provide strong evidence of conspecificity of the morphologically variable macropterous and strongly brachypterous individuals of C. breviclava . Macropterous females of the new species are most similar to those of C. detritus Bakkendorf, also known from Switzerland. New records are provided for some other species of Cleruchus Enock in Europe. A key to both sexes of the described European species of the genus is given.
... The PCR was performed in a 25 µL reaction volume: 2 µL of DNA, 8.5 µL molecular grade water, 1 µL of each primer (0.3 µM each), 12.5 µL 2 × Taq Master Mix (Dye Plus) (Vazyme, Nanjing, China). The thermocycling conditions followed that of Triapitsyn et al. [42] and Morse et al. [43]. ...
Saxaul is a kind of dominant perennial psammophyte that widely distributes in arid and semi-arid desert areas, and it has multiple functions in preventing desertification, especially in windbreak and sand fixation. Various gall inducers induce galls on the saxaul, including the flower-like gall. Parasitoids have great potentiality in controlling gall inducers. However, studies about gall inducers and parasitoids of flower-like galls on Haloxylon, as well as the parasitic efficacy of the parasitoids, are rarely reported. In this study, the flower-like galls were observed on Haloxylon ammodendron and H. persicum in Fukang, Xinjiang, China. Two types of flower-like galls were found on H. ammodendron, while only one type was found on H. persicum. In total, five species of gall inducers and three species of parasitoids were obtained from the galls mentioned above. All the galls were induced by Caillardia (Hemiptera: Aphalaridae), which were mostly bivoltine in Fukang. Besides, their parasitoids Psyllaephagus caillardiae and P. longiventris could be observed on all the types of galls. Additionally, correlative studies on the parasitization indexes demonstrated that all the dominant parasitoids of diverse flower-like galls were P. caillardiae, which were slightly more in number than the P. ogazae discovered in the flower bud-like galls. In addition, the relevance between the emergence or lifespan of parasitoids and temperature was also investigated. The results showed that the number of parasitoids emerging decreased rapidly after a period of enhancement with the increase of temperature, including an optimum temperature, while the lifespan of wasps gradually shortened with the temperature rising. Our results highlight the importance of the biological investigation of parasitoids in the gall inducers lived in closed galls, which may provide critical evidence for us to understand its potential application in biological control.
... After an initial denaturing step of 2 min at 94°C, thermocycling conditions were: five cycles of 30 s at 94°C, 1 min 30 s at 45°C, and 1 min at 72°C; followed by a further 35 cycles in which the annealing temperature was increased to 51°C; and a final extension of 5 min at 72°C. We also amplified and sequenced the internal transcribed spacer 2 (ITS2) region of ribosomal RNA (rRNA) using the primers 58SF (5'-TGTGAACTGCAGGACACATGAAC-3') and ITS4 (5'-TCCTCCGCTTATTGATATGC-3') as detailed in Morse et al. (2016). Amplifications were confirmed by gel electrophoresis and PCR products were purified using a DNA Clean & Concentrator™-5 kit (Zymo Research, Irvine, California, USA). ...
Members of the Anagrus atomus (L.) (Hymenoptera: Mymaridae) species complex within the atomus species group of the nominate subgenus of Anagrus Haliday are common egg parasitoids of typhlocybine leafhoppers (Hemiptera: Cicadellidae: Typhlocybinae) in grape and other agroecosystems in Europe and North America. Here, all the species in this complex are reassessed using both molecular and morphometric methods. Findings indicate that this complex includes A. erythroneurae S. Trjapitzin and Chiappini syn. n., A. lindberginae Nugnes and Viggiani syn. n., A. nepetellae Viggiani and Nugnes syn. n., A. parvus Soyka syn. n., and A. ustulatus Haliday syn. n., all of which are synonymised with A. (Anagrus) atomus based on the presented genetic evidence. We consider the slight morphological differences among these nominal species to be at most due to intraspecific, rather than interspecific, variability. As such, populations of A. atomus in the New World (the Nearctic region, Argentina, and Chile) and New Zealand, where it is likely not native, appear to be the result of inadvertent spread with agricultural crops and other plants by European settlers.
... In a separate PCR, the internal transcribed spacer 2 (ITS2) region of nuclear ribosomal RNA (rRNA) was amplified for all 3 specimens extracted by PRJ (HotSHOTand Chelex 100 -extractions) using the primers, 58SF (5'-GTGAACTGCAGGACA-CATGAAC-3') (Porter and Collins 1991) and ITS4 (5'-TCCTCCGCTTATTGA-TATGC-3') (White et al. 1990), as described in Morse et al. (2016). ...
Fairyfly (Hymenoptera, Mymaridae) egg parasitoids of the tea green leafhopper Empoasca (Matsumurasca) onukii Matsuda (Hemiptera, Cicadellidae), an economically important pest in Asia of the tea plant, Camelliasinensis, were identified from specimens reared in Japan. Using a combination of genetic and morphological evidence, Anagrus (Anagrus) rugmanjonesi Triapitsyn & Adachi-Hagimori, sp. n., is described and illustrated. It is shown to be different from the most similar A.turpanicus Triapitsyn & Hu, an egg parasitoid of a leafhopper pest of cultivated grapes which is known from Xinjiang Uyghur Autonomous Region in China. Mitochondrial and nuclear ribosomal DNA sequence data provide clear evidence for the separation of A.rugmanjonesi from A.turpanicus and other members of the Anagrusincarnatus Haliday species complex. A key to females of the Japanese species of Anagrus Haliday is given. Two other species of Mymaridae, Aresconenocki (Subba Rao & Kaur) and Stethyniumempoascae Subba Rao, are also identified, albeit the latter one only tentatively. Both latter taxa are newly recorded from Japan, and E.onukii represents their new host association.
... The internal transcribed spacer 2 (ITS2) region of nuclear ribosomal RNA (rRNA) was also amplified using the primers, 58SF (5ʹ-GTGAACTGCAGGACACATGAAC-3ʹ) (Porter and Collins 1991) and ITS4 (5ʹ-TCCTCCGCTTATTGATATGC-3ʹ) (White et al. 1990), as described in Morse et al. (2016) with the exception that dUTP was ultimately replaced with dTTP to facilitate cloning, since direct sequencing of the ITS2 amplicon failed for the majority of specimens examined (see results). The ITS2 is part of the ribosomal cistron, of which there are hundreds of tandem copies in a typical eukaryote genome, creating potential for sequence variation among copies (Buckler et al. 1997). ...
Anagrus nilaparvartae Pang and Wang has been recorded frequently as an egg parasitoid of rice planthoppers in SE Asia, especially of brown planthopper Nilaparvata lugens (Stål). However, what appears to be the same species was often identified either as the morphologically similar Holarctic species Anagrus incarnatosimilis Soyka (as A. incarnatus Haliday) or misidentified as an unrelated, strictly New World species A. flaveolus Waterhouse, which, unlike A. nilaparvartae, does not belong to the A. incarnatus ‘species complex’ of Anagrus (Anagrus Haliday). Besides being mostly geographically separate from each other (except in the Eastern Palaearctic region), A. nilaparvatae and A. incarnatosimilis were not known to share any hosts. Using a combination of genetic analyses and morphometric methods, specimens of A. incarnatosimilis collected in Europe were shown to be not significantly different from those of A. nilaparvatae reared from eggs of rice planthoppers and leafhoppers mainly in Taiwan and also in Malaysia. Moreover, both A. incarnatosimilis and A. nilaparvatae as well as the morphologically very similar Nearctic species A. columbi Perkins were found to be genetically identical to the common Palaearctic species A. incarnatus Haliday based on both CO1 (mitochondrial) and ITS2 (nuclear) gene regions. Consequently, A. columbi Perkins syn. n. and A. nilaparvatae Pang and Wang syn. n. are synonymised under A. incarnatus, which is re-diagnosed and illustrated. Anagrus incarnatosimilis Soyka stat. rev. (along with its eight current synonyms) is reinstated as a synonym of A. incarnatus.
http://zoobank.org/urn:lsid:zoobank.org:pub:70441879-F52B-46FD-8136-6CDAC7B76511
... The polymerase chain reaction (PCR) was used to amplify a section of the D2 domain of 28S nuclear ribosomal RNA (rRNA) using the primers 28sF3633 (5'-TACC-GTGAGGGAAAGTTGAAA-3') and 28sR4076 (5'-AGACTCCTTGGTCCGT-GTTT-3') as described in Rugman-Jones et al. (2010). A second rRNA locus, the internal transcribed spacer 2 (ITS2), also was amplified using the primers 58SF (5'-GTGAACTGCAGGACACATGAAC-3'; Porter & Collins 1991) and ITS4 (5'-TCCTCCGCTTATTGATATGC-3'; White et al. 1990) as described in Morse et al. (2016). Finally, the "barcoding" region of the mitochondrial cytochrome c oxidase subunit I gene (COI) was amplified using LCO1490 (5'-GGTCAACAAATCATAAAGATATTGG-3') and HCO2198 (5'-TAAACTTCAGGGTGACCAAAAAATCA-3'; Folmer et al. 1994) as described in Rugman-Jones et al. (2012). ...
Parasitoids, both primary and secondary (hyperparasitoids), of Hypogeococcus spp. mealybugs (Hemiptera: Pseudococcidae) are reviewed to report results of the surveys in the New World conducted during 2009 to 2017 for prospective natural enemies of the Harrisia cactus mealybug, Hypogeococcus sp., which is devastating native cacti in Puerto Rico and threatening cacti in the adjacent Caribbean islands. Five species of Encyrtidae (Hymenoptera: Chalcidoidea) are recorded as primary parasitoids of Hypogeococcus spp., including the newly described Leptomastidea hypogeococci Triapitsyn sp. n., which is the only species of the genus Leptomastidea García Mercet in the New World where the clava of the female antenna is contrastingly white. Genetic analysis of the individuals of L. hypogeococci from Argentina, Brazil, and Puerto Rico (USA) corroborates the morphological data that the same species occurs in South America, the Caribbean islands, and Florida (USA). A key to the New World species of Leptomastidea is given and taxonomic notes are provided on its other known species in the Neotropical region. Leptomastidea antillicola Dozier, syn. n. from Puerto Rico is synonymized under L. abnormis (Girault). Based on the presented molecular data, Anagyrus ciomperliki Triapitsyn syn. n. (Encyrtidae), originally described from Puerto Rico, is synonymized under A. quilmes Triapitsyn, Logarzo & Aguirre, where the known distributional range is expanded to also include Brazil. Anagyrus cachamai Triapitsyn, Logarzo & Aguirre, A. lapachosus Triapitsyn, Aguirre & Logarzo, and A. quilmes are newly recorded from Paraguay. The previously unknown male of Prochiloneurus argentinensis (De Santis) (Encyrtidae) is described from Misiones Province of Argentina, and that of P. narendrani Noyes & Triapitsyn is described from Mona Island, Puerto Rico. So far, Anagyrus cachamai and A. lapachosus are considered to be the primary target species for introduction from Argentina and Paraguay into Puerto Rico for the biological control of Harrisia cactus mealybug. The holotype of Anagyrus tanystis De Santis from Buenos Aires, Argentina, host associations are unknown, and is illustrated to facilitate its recognition from other congeneric species.
... DNA was also extracted from three further taxa in the incarnatus species group of Anagrus: A. avalae Soyka (UK, England, Kent Co., Sevenoaks, The polymerase chain reaction (PCR) was employed to amplify the "barcoding" region of the mitochondrial cytochrome c oxidase subunit I gene (COI) using LCO1490 (5′-GGTCAACAAATCATAAAGATATTGG-3′) and HCO2198 (5′-TAAACTTCAGGGTGACCAAAAAATCA-3′; Folmer et al 1994), as described in Rugman-Jones et al (2012). In a separate PCR, the internal transcribed spacer 2 (ITS2) region of nuclear ribosomal RNA (rRNA) was also amplified using the primers, 58SF (5′-GTGAACTGCAGGACACATGAAC-3′) (Porter and Collins 1991) and ITS4 (5′-TCCTCCGCTTATTGATATGC-3′) (White et al 1990), as described in Morse et al (2016). All reactions were performed in 25-μL volumes on a Mastercycler® ep gradient S thermocycler (Eppendorf North America Inc., New York, NY, USA). ...
The common New World egg parasitoid of the corn leafhopper Dalbulus maidis (DeLong) (Hemiptera: Cicadellidae), an economically important pest of maize from Argentina to southern USA, has long been misidentified as the Palaearctic species Anagrus incarnatus Haliday or its synonym A. breviphragma Soyka (Hymenoptera: Mymaridae). Using a combination of genetic and morphometric methods, and available biological information, specimens reared from eggs of D. maidis in Argentina and Mexico, described and illustrated here as Anagrus (Anagrus) virlai Triapitsyn sp. n., are shown to be different from those of A. incarnatus from the Palaearctic region. Mitochondrial and nuclear ribosomal DNA sequence data provide clear evidence for the separation of the two species. Anagrus virlai is also known from Brazil, Colombia, Guadeloupe (France), and Guyana.
... The key limiting factor for any successful O. perseae introduction pathway is that this pest is strictly a foliage feeder and like many other small leaf feeding plant pests introduced into California, it may have been introduced on live plant material (Dowell et al. 2016). The requirement of O. perseae for fresh foliage to survive indicates there is minimal risk of O. perseae introduction associated with the movement of washed fruit from Mexico to other countries, including California (but see Morse et al. 2009Morse et al. , 2016. Instead, the biology of O. perseae and the molecular evidence presented here implies that its introduction from Mexico, presumably Michoacán, into California was most likely mediated through the movement of infested plant material possibly intended for avocado propagation (i.e., budwood or whole plants). ...
Oligonychus perseae Tuttle, Baker & Abbatiello (Acari: Tetranychidae) is an economically important foliar pest of avocados from Mexico. Invasive O. perseae populations became established throughout the commercial avocado system in California (USA) during the early 1990s, but the putative geographic origin(s) of the California O. perseae populations has not been investigated. To address this shortcoming, a series of population genetic analyses for O. perseae populations representative of a broad geographic sample range was conducted. This study identified a single mitochondrial cytochrome c oxidase subunit I (COI) haplotype match between O. perseae populations collected in California with those from 4 municipalities in Michoacán, Mexico, part of the presumptive native range of this pest. Interestingly, this haplotype also was collected from avocados at 2 locations in Baja California, Mexico, and it was identified from a representative sample from Israel where O. perseae is an invasive avocado pest. Molecular data confirm the likely Mexican origin of invasive O. perseae populations in California, and may help delimit the geographic area to be searched for coevolved natural enemies of O. perseae that could be introduced into California as part of a future classical biological control program targeting this pest. Moreover, molecular results uncovered significant and concordant genetic divergence in both mitochondrial (COI) and ribosomal DNA markers, i.e.,internal transcribed spacer 2 (ITS2) and a section of the 28S gene region, pointing to the potential occurrence of a cryptic species complex within O. perseae. The implications of these findings on future taxonomic and molecular work for O. perseae are discussed.
... 7-9), one of which, vouchered as slide E2016-2002, contained an adult female of Encarsia lounsburyi (Berlese & Paoli) (Hymenoptera: Aphelinidae) and is a new host association for this species. Encarsia lounsburyi is globally distributed and associated with 50 armored scale host species (Noyes 2016) but is neither one of the 5 species collected in field surveys for armored scale pests in avocado orchards in Michoacán, Mexico (Lázaro-Castellanos et al. 2012), nor a species identified in intercepted Mexican avocados or during field and packing house surveys for parasitoids in California (Morse et al. 2016). In Florida, E. lounsburyi and the closely related Encarsia citrina (Craw) (Hymenoptera: Aphelinidae) have been documented armored scale parasitoids since at least 1949 (Thompson & Griffiths 1949;Muma & Clancy 1961). ...
A new parasitoid-host association between Davidsonaspis aguacatae (Evans, Watson & Miller) (Hemiptera: Diaspididae) and Encarsia lounsburyi (Berlese & Paoli) (Hymenoptera: Aphelinidae) is documented, and an overview of armored scales infesting Hass avocados intercepted in Florida is given. An observation of the occurrence of crawler scales developing inside a parasitized female scale is discussed.
Scale insects are major pests of crops and ornamental plants, with Diaspididae, Pseudococcidae, and Coccidae being the three most important families. They can cause economic damage by sucking sap, injecting poisons, and transmitting viruses. Mealybugs and soft scales may also cause indirect damage by excreting honeydew onto the plant surface. National phytosanitary services conduct active inspections for these insects, and morphological identification is achievable, but difficult. Diaspididae are a family of fast-breeding insects that suck plant sap and produce a sticky material called pad, which attracts ants. Diaspididae is a type of sap-sucking insect that affects hard-leaved orchids, citrus, ficus, and other plants. Females are aphids and generate wax that provides a protective shield. The shield itself can be circular or extended and can range in color from light to dark brown. Diaspididae produces eggs (up to 3000 pieces) under the shield, from which very small, mobile young individuals hatch. Males have two front wings and can fly to other plants; their life cycle is only a few days long.
Anaphes (Anaphes) flavipes (Foerster), a fairyfly (Hymenoptera: Mymaridae) native of Europe, is an economically important egg parasitoid for the natural control of Oulema spp. leaf beetle (Coleoptera: Chrysomelidae) pests of cereal crops such as barley, oats, rye, and wheat in Europe, and for the classical biological control of the invasive Oulema melanopus (L.) in North America. A morphologically very similar Anaphes (Anaphes) nipponicus Kuwayama, known from mainland China, Japan, Republic of Korea, Far East of Russia and Taiwan, is an egg parasitoid of Oulema oryzae (Kuwayama), a pest of rice mainly in temperate parts of East Asia. The nuclear 28S-D2 and ITS2 and the mitochondrial COI genes were used as markers to compare specimens of A. (Anaphes) flavipes reared from eggs of an Oulema sp. on barley in Germany with those of A. (Anaphes) nipponicus reared from eggs of O. oryzae on rice in Honshu Island, Japan. Because the resulting sequences are practically identical, within an expected intraspecific genetic variability, conspecificity of these two nominal species has been confirmed, and consequently A. (Anaphes) nipponicus Kuwayama, 1932, syn. n. is synonymized with A. (Anaphes) flavipes (Foerster, 1841). Taxo-nomic notes and illustrations are provided for the specimens of both sexes of A. (Anaphes) flavipes from Japan to facilitate their recognition.
Anaphes (Anaphes) flavipes (Foerster), a fairyfly (Hymenoptera: Mymaridae) native of Europe, is an economically important egg parasitoid for the natural control of Oulema spp. leaf beetle (Coleoptera: Chrysomelidae) pests of cereal crops such as barley, oats, rye, and wheat in Europe, and for the classical biological control of the invasive Oulema melanopus (L.) in North America. A morphologically very similar Anaphes (Anaphes) nipponicus Kuwayama, known from mainland China, Japan, Republic of Korea, Far East of Russia and Taiwan, is an egg parasitoid of Oulema oryzae (Kuwayama), a pest of rice mainly in temperate parts of East Asia. The nuclear 28S-D2 and ITS2 and the mitochondrial COI genes were used as markers to compare specimens of A. (Anaphes) flavipes reared from eggs of an Oulema sp. on barley in Germany with those of A. (Anaphes) nipponicus reared from eggs of O. oryzae on rice in Honshu Island, Japan. Because the resulting sequences are practically identical, within an expected intraspecific genetic variability, conspecificity of these two nominal species has been confirmed, and consequently A. (Anaphes) nipponicus Kuwayama, 1932, syn. n. is synonymized with A. (Anaphes) flavipes (Foerster, 1841). Taxonomic notes and illustrations are provided for the specimens of both sexes of A. (Anaphes) flavipes from Japan to facilitate their recognition.
Unintentional biological control, defined as accidental introductions of natural enemies, exceeds in number of species those introduced intentionally by importation (classical) biological control. Several factors favor this: a general surge in international trade; lack of surveillance for species that are not associated with live plants or animals; inability to intercept tiny organisms such as egg parasitoids or entomopathogens; invasive bridgehead effects and receptive bridgehead effects that allow rapid establishment; and lack of aggressive surveillance for pests already established. This chapter reviews the available data for non-native natural enemies in several continents and islands, contrasting proportions due to intentional versus unintentional introductions, in particular for parasitoids in the order Hymenoptera. We also profile a number of recent frequent and surprisingly rapid accidental natural enemy introductions, including insect parasitoids, pathogens, and insect herbivores of invasive weeds. These examples raise important issues of the role of systematics and genetic considerations for unintentional introductions, and also call into question the regulatory emphasis on rigorous and protracted protocols for importation biological control, when adventive unintentional introductions have a high probability to displace or disrupt this planned process.
This proceedings contains papers dealing with issues affecting biological control, particularly pertaining to the use of parasitoids and predators as biological control agents. This includes all approaches to biological control: conservation, augmentation, and importation of natural enemy species for the control of arthropod targets, as well as other transversal issues related to its implementation. It has 14 sessions addressing the most relevant and current topics in the field of biological control of arthropods: (i) Accidental introductions of biocontrol agens: positive and negative aspects; (ii) The importance of pre and post release genetics in biological control; (iii) How well do we understand non-target impacts in arthropod biological control; (iv) Regulation and access and benefit sharing policies relevant for classical biological control approaches; (v) The role of native and alien natural enemy diversity in biological control; (vi) Frontiers in forest insect control; (vii) Biocontrol marketplace I; (viii) Weed and arthropod biological control: mutual benefits and challenges; (ix) Maximizing opportunities for biological control in Asia's rapidly changing agro-environments; (x) Biological control based integrated pest management: does it work?; (xi) Exploring the compatibility of arthropod biological control and pesticides: models and data; (xii) Successes and uptake of arthropod biological control in developing countries; (xiii) Socio-economic impacts of biological control; (xiv) Biocontrol marketplace II.
Girault (1917) very briefly described and diagnosed the encyrtid wasp species Ooencyrtus californicus Girault (Hymenoptera: Encyrtidae) with the following limited data (p. 22): “Sacramento, California, from bug eggs on Pinus sabiniana, September”. The first author examined its two syntypes, poorly mounted on a slide, of which only parts of the four antennae and a slightly damaged fore wing remain (Triapitsyn et al. 2020). They concluded that this species was better considered a nomen dubium until fresh specimens could be collected from the same host plant in or near the type locality. In July 2019, an effort was made to re-collect O. californicus from foothill (or gray) pine, Pinus sabiniana (Pinaceae), in the Oakhurst area of Madera County, California, USA, where this pine is abundant, but no specimens were captured. At the same time, a very similar insect was collected from sentinel eggs of the invasive stink bug Bagrada hilaris (Burmeister) in Riverside, California. This insect was cultured in the laboratory as part of a B. hilaris biological control program. Due to the poor preservation of the type specimens and in the absence of genetic evidence, it was impossible to positively and properly attribute specimens of this newly collected parasitoid to O. californicus. Therefore, to provide a much needed scientific name for this native egg parasitoid, it was described as Ooencyrtus lucidus Triapitsyn & Ganjisaffar in Triapitsyn et al. (2020). The two nominal species were separated based on minor differences in the proportions of the scape, pedicel, and first funicular segment of the female antenna (Triapitsyn et al. 2020). John S. Noyes, world expert on Encyrtidae and one of the reviewers of Triapitsyn et al. (2020), disagreed with the erection of O. lucidus as a new taxon based on the morphological similarities of the female antenna with that of O. californicus, so the description was published with the understanding that the two might be conspecific. But to settle this one way or another new specimens of O. californicus had to be collected to allow morphological and molecular analyses.
In support of a biological control program in California, USA, against the bagrada bug, Bagrada hilaris (Burmeister) (Hemiptera, Pentatomidae), an invasive pest of Asian origin, colonies of two species of Ooencyrtus Ashmead (Hymenoptera, Encyrtidae) are maintained using B. hilaris eggs as host. One of them, Ooencyrtus mirus Triapitsyn & Power, sp. nov. , is of Pakistani origin. It displays natural preference for bagrada bug eggs and is being evaluated in quarantine as a candidate for classical biological control. The other, Ooencyrtus lucidus Triapitsyn & Ganjisaffar, sp. nov. , appears to be native to California, and we believe it switched to B. hilaris from native pentatomid hosts. Both new species are described and illustrated, as is the Old World species Ooencyrtus telenomicida (Vassiliev), for which a neotype is designated. The presented morphometric evidence as well as mitochondrial and nuclear ribosomal DNA sequence data separate Ooencyrtus mirus from O. telenomicida . A lectotype is designated for Ooencyrtus californicus Girault from California, which is morphologically similar to O. lucidus .
For phytophagous insects and plant pathogens, the unregulated movement of plant material can inadvertently promote long-distance spread, facilitating biological invasions. Such human-assisted spread has contributed to the invasion of the Asian citrus psyllid (Diaphorina citri), a vector of the pathogens associated with huan-glongbing. Following the detection of D. citri in California, regulations were instituted to limit movement of D. citri host plants, by mandating insecticide treatments of citrus nursery stock, and limiting the amount of time host plants can reside at retail sites. We used a set of surveys and a field experiment to evaluate how well these steps mitigate the threat of containerized citrus playing a role in D. citri spread. A qualitative analysis of data collected by state regulators throughout Southern California found that containerized citrus may reside at retail sites for extended durations, in extreme cases upwards of 2 years post treatment. More detailed surveys at nearly 30 retail sites in Southern California showed that the majority of citrus plants were present past the 90 day regulatory limit, 33% had been treated more than 1 year prior, and 90% had imidacloprid residues below those known to be effective against D. citri nymphs. A field experiment confirmed that imidacloprid residues in trees grown in containers were affected by citrus species, watering level, soil mix, and time since treatment. Overall, plants had D. citri-effective residues for approximately 12 weeks, suggesting that imidacloprid treatments should protect the majority of containerized citrus against D. citri for approximately the duration of the 90 day regulatory limit. To further protect trees from infestation, nurseries should be encouraged to adopt practices that maximize the effectiveness of insecticide treatments, including ways to reduce residence times of host plants at retail sites.
Scale insects (Hemiptera: Coccoidea) are small herbivorous insects found on all continents except Antarctica. They are extremely invasive, and many species are serious agricultural pests. They are also emerging models for studies of the evolution of genetic systems, endosymbiosis and plant-insect interactions. ScaleNet was launched in 1995 to provide insect identifiers, pest managers, insect systematists, evolutionary biologists and ecologists efficient access to information about scale insect biological diversity. It provides comprehensive information on scale insects taken directly from the primary literature. Currently, it draws from 23 477 articles and describes the systematics and biology of 8194 valid species. For 20 years, ScaleNet ran on the same software platform. That platform is no longer viable. Here, we present a new, open-source implementation of ScaleNet. We have normalized the data model, begun the process of correcting invalid data, upgraded the user interface, and added online administrative tools. These improvements make ScaleNet easier to use and maintain and make the ScaleNet data more accurate and extendable.
Database URL: http://scalenet.info
Based on examination of the literature and specimens, 208 described species in 90 genera of Encyrtidae are listed from California. Data on the original publication, deposition of types, geographic distribution and host records of these species are presented. Forty-three species were established in biocontrol programs, 157 are presumed native, 7 appear to be ad- ventitious introductions, and the origin of one is undetermined. An additional 276 morphospecies are also listed as present in the state within an additional 21 described genera and potentially up to 20 undescribed genera. Altogether, 31 new genera and 36 new species are recorded for the state, as well as 70 new parasitoid-host records. Errors pertaining to California taxa in previously published papers are corrected. Metaphycus immaculatus (Howard) is reported as a new combination (from Aphycus Mayr). Three appendices are included: a host/parasitoid listing for the described species present in the state, a listing of taxa previously reported from California under invalid names, and a list of taxa either erroneously reported from the state, or unsuccessful biocontrol introductions.
Thousand cankers disease (TCD) of walnut trees (Juglans spp.) results from aggressive feeding in the phloem by the walnut twig beetle (WTB), Pityophthorus juglandis, accompanied by inoculation of its galleries with a pathogenic fungus, Geosmithia morbida. In 1960, WTB was only known from four U.S. counties (in Arizona, California, and New Mexico), but the species has now (2014) invaded over 115 counties, representing much of the western USA, and at least six states in the eastern USA. The eastern expansion places TCD in direct proximity to highly valuable (> $500 billion) native timber stands of eastern black walnut, Juglans nigra. Using mitochondrial DNA sequences, from nearly 1100 individuals, we examined variation among 77 samples of WTB populations across its extended range in the USA, revealing high levels of polymorphism and evidence of two divergent lineages. The highest level of genetic diversity for the different lineages was found in the neighboring Madrean Sky Island and Western New Mexico regions, respectively. Despite their proximity, there was little evidence of mixing between these regions, with only a single migrant detected among 179 beetles tested. Indeed, geographic overlap of the two lineages was only common in parts of Colorado and Utah. Just two haplotypes, from the same lineage, predominated over the vast majority of the recently expanded range. Tests for Wolbachia proved negative suggesting it plays no role in "driving" the spread of particular haplotypes, or in maintaining deep levels of intraspecific divergence in WTB. Genotyping of ribosomal RNA corroborated the mitochondrial lineages, but also revealed evidence of hybridization between them. Hybridization was particularly prevalent in the sympatric areas, also apparent in all invaded areas, but absent from the most haplotype-rich area of each mitochondrial lineage. Hypotheses about the specific status of WTB, its recent expansion, and potential evolutionary origins of TCD are discussed.
A new species of armored scale, Abgrallaspis aguacatae Evans, Watson, and Miller spec. nov. is described and illustrated from specimens collected on avocado fruit from Mexico. This species has caused considerable concern as a quarantine issue in the United States. A key to the armored scale species known to feed on avocado worldwide is provided.
The parasitoid wasp species Cales noacki Howard (Aphelinidae) is an important biological control agent against woolly whitefly, Aleurothrixus floccosus (Aleyrodidae), in citrus-growing regions worldwide. We recently discovered two cryptic species of Cales on citrus in California: Cales noacki and Cales rosei Mottern. Examination of historical biological control records is combined with a geometric morphometric analysis of fore wing shape to reconstruct aspects of the biological control history of Cales. Our analyses indicate that C. rosei is most likely descended from populations introduced from Argentina in the mid 1970s, with newly collected specimens from California clustering with Argentinian slide-mounted specimens from the original importation. Our analyses support a Chilean origin of C. noacki. Morphometrics confirms the earlier synonymy of Diaspidophilus pallidus Brèthes with C. noacki. A potential third species was imported from Brazil and Tucumán, Argentina, although it does not appear to have established in the field. The implications of these results for future studies on the bionomics of Cales and also the utility of geometric morphometric analyses for species identification and description are discussed.
With the increasing availability of molecular data, maximum likelihood approaches have gained a new central role in phylogenetic reconstructions. Extremely fast tree-search algorithms have been developed to handle data sets of ample size in reasonable time. In the past few years, RAxML has achieved great relevance in this field and obtained wide distribution among evolutionary biologists and taxonomists because of its high computational performance and accuracy. However, there are certain drawbacks with regard to its usability, since the program is exclusively command-line based. To overcome this problem, we developed raxmlGUI, a graphical user interface that makes the use of RAxML easier and highly intuitive, enabling the user to perform phylogenetic analyses of varying complexity. The GUI includes all main options of RAxML, and a number of functions are automated
or simplified. In addition, some features extend the standard use of RAxML, like assembling concatenated alignments with automatic partitioning. RaxmlGUI is an open source Python program, available in a cross-platform package that incorporates RAxML executables for the main operating systems. It can be downloaded from http://sourceforge.net/projects/raxmlgui/.
Keywords: Rapid bootstrap; Graphical user interface; Maximum likelihood; Phylogenetic analyses; Python; RAxML
Chalcidoidea (Hymenoptera) are extremely diverse with more than 23,000 species described and over 500,000 species estimated to exist. This is the first comprehensive phylogenetic analysis of the superfamily based on a molecular analysis of 18S and 28S ribosomal gene regions for 19 families, 72 subfamilies, 343 genera and 649 species. The 56 outgroups are comprised of Ceraphronoidea and most proctotrupomorph families, including Mymarommatidae. Data alignment and the impact of ambiguous regions are explored using a secondary structure analysis and automated (MAFFT) alignments of the core and pairing regions and regions of ambiguous alignment. Both likelihood and parsimony approaches are used to analyze the data. Overall there is no impact of alignment method, and few but substantial differences between likelihood and parsimony approaches. Monophyly of Chalcidoidea and a sister group relationship between Mymaridae and the remaining Chalcidoidea is strongly supported in all analyses. Either Mymarommatoidea or Diaprioidea are the sister group of Chalcidoidea depending on the analysis. Likelihood analyses place Rotoitidae as the sister group of the remaining Chalcidoidea after Mymaridae, whereas parsimony nests them within Chalcidoidea. Some traditional family groups are supported as monophyletic (Agaonidae, Eucharitidae, Encyrtidae, Eulophidae, Leucospidae, Mymaridae, Ormyridae, Signiphoridae, Tanaostigmatidae and Trichogrammatidae). Several other families are paraphyletic (Perilampidae) or polyphyletic (Aphelinidae, Chalcididae, Eupelmidae, Eurytomidae, Pteromalidae, Tetracampidae and Torymidae). Evolutionary scenarios discussed for Chalcidoidea include the evolution of phytophagy, egg parasitism, sternorrhynchan parasitism, hypermetamorphic development and heteronomy.
Dispersal and colonization of new areas by armored scale insects (Hemiptera: Diaspididae) is achieved by mobile first-instar nymphs, called crawlers. Few studies have considered the actual mechanisms by which crawlers disperse, and although crawlers are capable of actively wandering over short distances (generally < 1 m), their dispersal over longer distances has been thought to be wind-mediated. Here, we present evidence of a potentially more important means of dispersal over longer distances (> 1 m). We first confirmed that crawlers of four species of Diaspididae [Abgrallaspis aguacatae Evans, Watson & Miller; Hemiberlesia lataniae (Signoret); Aspidiotus nerii Bouché; and Diaspidiotus perniciosus (Comstock)] have four hairs on the end of each of their legs and that each of these hairs ends in a suction cup-like structure, reminiscent of the attachment structures possessed by phoretic mites. In a controlled environment, using crawlers of A. nerii, we then showed that the crawlers use these structures to attach themselves to three different insect species [Musca domestica L., Cryptolaemus montrouzieri Mulsant and Linepithema humile (Mayr)] and can effectively be moved phoretically by these insects. Crawlers can remain attached to flying insects for considerable periods of time, suggesting that this may be an important means of dispersal for armored scale insects. The importance of phoresy for diaspidid dispersal in the field remains to be determined.
Over the past three decades, Western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), has become a major worldwide pest of many agricultural and horticultural crops. In response, much time, money, and effort have been put into pure and applied research focusing on the biology and control of this pest. Western flower thrips is native to Western North America and widespread in California. High levels of variation in basic biology, pest status, and resistance to insecticides bring into question the specific status of Western flower thrips. We used nuclear-mitochondrial barcoding to compare DNA sequences of nuclear and mitochondrial genes between Western flower thrips populations across California, looking for association between these unlinked loci. Sequences of D2 domain of 28S and cytochrome c oxidase I gene revealed the existence of two distinct but sympatric genetic entities, and we describe a simple polymerase chain reaction-based method for diagnosing these entities. The complete association of these nuclear and mitochondrial loci in areas of sympatry is indicative of reproductive isolation and the existence of two cryptic species, both of which key out to Western flower thrips by using morphological characters. The finding that Western flower thrips is a complex of two species has important implications for past, current, and most importantly future research on these pests.
Between 1914 and 2007, a quarantine protected California avocado, Persea americana Mill., groves from pests that might be introduced into the state along with fresh, imported avocados. Soon after Mexican avocados were first allowed entry on 1 February 2007, live specimens of several species of armored scales (Hemiptera: Diaspididae) not believed to be present in California were detected on 'Hass' avocados entering the state from Mexico. Initially, the California Department of Food and Agriculture (CDFA) prevented avocados infested with these scales from entering the state or required that they be fumigated with an approved treatment such as methyl bromide. After a Science Advisory Panel meeting in May 2007, U.S. Department of Agriculture-Animal and Plant Health Inspection Service (USDA-APHIS) reaffirmed its position that armored scales on shipments of fruit for consumption (including avocados) pose a "low risk" for pest establishment. In compliance with APHIS protocols, as of 18 July 2007, CDFA altered its policy to allow shipments of scale-infested avocados into the state without treatment. Here, we report on sampling Mexican avocados over an 8-mo period, September 2007-April 2008. An estimated 67 million Mexican Hass avocados entered California over this period. Based on samples from 140 trucks containing ≈15.6% of this volume of fruit, we estimate that ≈47.6 million live, sessile armored scales and an additional 20.1 million live eggs and crawlers were imported. We found eight probable species of armored scales in the samples, seven of these are not believed to occur in California; 89.3% of the live scales were Abgrallaspis aguacatae Evans, Watson and Miller, a recently described species. In contrast to the USDA-APHIS opinion, we believe the volume of shipments and levels of live scales they contain present a significant risk to California's US $300 million avocado industry and to other crops that might become infested by one or more of these exotic species.
Despite recent advances achieved by application of high-performance computing methods and novel algorithmic techniques to maximum likelihood (ML)-based inference programs, the major computational bottleneck still consists in the computation of bootstrap support values. Conducting a probably insufficient number of 100 bootstrap (BS) analyses with current ML programs on large datasets-either with respect to the number of taxa or base pairs-can easily require a month of run time. Therefore, we have developed, implemented, and thoroughly tested rapid bootstrap heuristics in RAxML (Randomized Axelerated Maximum Likelihood) that are more than an order of magnitude faster than current algorithms. These new heuristics can contribute to resolving the computational bottleneck and improve current methodology in phylogenetic analyses. Computational experiments to assess the performance and relative accuracy of these heuristics were conducted on 22 diverse DNA and AA (amino acid), single gene as well as multigene, real-world alignments containing 125 up to 7764 sequences. The standard BS (SBS) and rapid BS (RBS) values drawn on the best-scoring ML tree are highly correlated and show almost identical average support values. The weighted RF (Robinson-Foulds) distance between SBS- and RBS-based consensus trees was smaller than 6% in all cases (average 4%). More importantly, RBS inferences are between 8 and 20 times faster (average 14.73) than SBS analyses with RAxML and between 18 and 495 times faster than BS analyses with competing programs, such as PHYML or GARLI. Moreover, this performance improvement increases with alignment size. Finally, we have set up two freely accessible Web servers for this significantly improved version of RAxML that provide access to the 200-CPU cluster of the Vital-IT unit at the Swiss Institute of Bioinformatics and the 128-CPU cluster of the CIPRES project at the San Diego Supercomputer Center. These Web servers offer the possibility to conduct large-scale phylogenetic inferences to a large part of the community that does not have access to, or the expertise to use, high-performance computing resources.
The internal transcribed spacer (ITS) of the ribosomal DNA is generally considered to be under low functional constraint, and it is therefore often treated as a typical nonfunctional spacer sequence. We have analyzed the ITS regions of five species from the Drosophila melanogaster subgroup, two Drosophila species from outside this group (D. pseudoobscura and D. virilis), as well as from the more distantly related dipteran fly Musca domestica. The sequence comparisons show a distinctive conservation/divergence pattern, indicating that some regions are more conserved than others. Moreover, secondary-structure calculations indicate several conserved structural elements within the ITS regions. On the other hand, a statistical test that allows us to estimate the fraction of sites that are not under selective constraint suggests that more than half of the spacer is apparently free to diverge and evolves with a rate that is close to the neutral rate of sequence evolution in Drosophila. The ITS sequences can be used to derive a molecular phylogeny for the species under study. We find that the ITS tree is largely in line with the so-far-known phylogeny of this group of species, with one difference. The species most distant within the D. melanogaster subgroup is D. yakuba, rather than D. orena, as is normally assumed.
Although much biological research depends upon species diagnoses, taxonomic expertise is collapsing. We are convinced that the sole prospect for a sustainable identification capability lies in the construction of systems that employ DNA sequences as taxon 'barcodes'. We establish that the mitochondrial gene cytochrome c oxidase I (COI) can serve as the core of a global bioidentification system for animals. First, we demonstrate that COI profiles, derived from the low-density sampling of higher taxonomic categories, ordinarily assign newly analysed taxa to the appropriate phylum or order. Second, we demonstrate that species-level assignments can be obtained by creating comprehensive COI profiles. A model COI profile, based upon the analysis of a single individual from each of 200 closely allied species of lepidopterans, was 100% successful in correctly identifying subsequent specimens. When fully developed, a COI identification system will provide a reliable, cost-effective and accessible solution to the current problem of species identification. Its assembly will also generate important new insights into the diversification of life and the rules of molecular evolution.
Unlabelled:
RAxML-VI-HPC (randomized axelerated maximum likelihood for high performance computing) is a sequential and parallel program for inference of large phylogenies with maximum likelihood (ML). Low-level technical optimizations, a modification of the search algorithm, and the use of the GTR+CAT approximation as replacement for GTR+Gamma yield a program that is between 2.7 and 52 times faster than the previous version of RAxML. A large-scale performance comparison with GARLI, PHYML, IQPNNI and MrBayes on real data containing 1000 up to 6722 taxa shows that RAxML requires at least 5.6 times less main memory and yields better trees in similar times than the best competing program (GARLI) on datasets up to 2500 taxa. On datasets > or =4000 taxa it also runs 2-3 times faster than GARLI. RAxML has been parallelized with MPI to conduct parallel multiple bootstraps and inferences on distinct starting trees. The program has been used to compute ML trees on two of the largest alignments to date containing 25,057 (1463 bp) and 2182 (51,089 bp) taxa, respectively.
Availability:
icwww.epfl.ch/~stamatak
GenBank (R) is a comprehensive database that contains publicly available nucleotide sequences for more than 260 000 named
organisms, obtained primarily through submissions from individual laboratories and batch submissions from large-scale sequencing
projects. Most submissions are made using the web-based BankIt or standalone Sequin programs and accession numbers are assigned
by GenBank staff upon receipt. Daily data exchange with the European Molecular Biology Laboratory Nucleotide Sequence Database
in Europe and the DNA Data Bank of Japan ensures worldwide coverage. GenBank is accessible through NCBI's retrieval system,
Entrez, which integrates data from the major DNA and protein sequence databases along with taxonomy, genome, mapping, protein
structure and domain information, and the biomedical journal literature via PubMed. BLAST provides sequence similarity searches
of GenBank and other sequence databases. Complete bimonthly releases and daily updates of the GenBank database are available
by FTP. To access GenBank and its related retrieval and analysis services, begin at the NCBI Homepage: www.ncbi.nlm.nih.gov
Basic Local Alignment Search Tool (BLAST) is a sequence similarity search program. The public interface of BLAST, http://www.ncbi.nlm.nih.gov/blast, at the NCBI website has recently been reengineered to improve usability and performance. Key new features include simplified
search forms, improved navigation, a list of recent BLAST results, saved search strategies and a documentation directory.
Here, we describe the BLAST web application's new features, explain design decisions and outline plans for future improvement.
Five new species of Encarsia from Veracruz, Mexico, state of Veracruz, are described: E. catemaco sp. n., E. dmitrii sp. n., E. flaviceps sp. n., E. trilineata sp. n. and E. tuxtla sp. n.
A new species of armored scale, Abgrallaspis aguacatae Evans, Watson, and Miller spec. nov. is described and illustrated from specimens collected on avocado fruit from Mexico. This species has caused considerable concern as a quarantine issue in the United States. A key to the armored scale species known to feed on avocado worldwide is provided.
Fortunately for California growers, avocado trees in this state seldom need pest control treatment. This relative freedom from pests is not mere happenstance. There are many potential pests in our groves at the present time. Numerous other pests occur on avocado trees throughout the foreign avocado growing regions of the world. California growers are protected from the pest species which are present in foreign countries by effective quarantine measures. The many potential pest species which are in our groves at the present time are generally kept under satisfactory natural balance by beneficial insects. Some of these beneficial insects were introduced into California by the Department of Biological Control, University of California; others are native to California. In order to facilitate establishment of newly introduced beneficial insects and to obtain the maximum efficiency from established species, it is essential to maintain satisfactory environmental conditions for them in the groves. For this reason, proper grove condition is an important part of the biological control program. Therefore, considerable attention has been given to the investigations of environmental factors which influence the activities of beneficial insects. During the years between approximately 1928 and 1940 the latania scale Heiniberlesia lataniae (Sign.) was the most serious pest of avocados in California. Groves were sprayed or fumigated for control of this pest. Today due to the effective work of natural enemies this insect is a minor pest. Artificial control is no longer practiced. The small yellow parasitic wasps Aphytis diaspidis (Howard) is the most important parasite of the latania scale.
Latania scale is probably the most important insect pest of the avocado in California. It has increased rapidly in the last few years and has caused damage in many groves. The scale is usually most abundant on the branches and twigs, but as the infestation increases, may also be found on the leaves and fruit. The smaller branches may be killed by a heavy infestation. The marketing quality of the fruit is impaired because of the presence of the scale on the rind. As the fruits mature the insects cause protuberances to extend from the rind down into the flesh, and when the rind is removed, corresponding depressions are left in the flesh. Distribution and Hosts D. B. Mackie of the California State Department of Agriculture reported the latania scale as being rather generally present in California on avocados in San Diego, Orange, and Los Angeles counties, with only a few light infestations found in Ventura County. He also gave statistics regarding the prevalence of the scale in each county during 1928 and 1930. Mackie also included a list of the host plants of the world on which the insect has been taken. This list includes some 163 host species and will be omitted from this paper. With regard to host plants, latania scale in southern California has not as yet become widespread. Aside from the avocado, which appears to be its primary host, this scale has been found only on Grevillea thelemanniana, canna lilies, and gladiolus corms. However, an extensive survey of host plants has not been made.
After hearing Mr. Newman's talk ("The Oriental Fruitfly"—John V. Newman), you are not going to feel so bad about hearing about the pests that you have here at the present time in California. If it is permissible to be facetious about such a serious problem, I am going to venture the opinion that if the Oriental fruitfly does get into California, we entomologists are going to come closer to justifying our two complimentary tickets to this fine banquet each year, which we enjoy so much, and the time that we take on your programs. To come back to our present California problems, the pest situation is not so serious compared to that of other sub-tropical fruit crops. That is no consolation to those of you who have had from fifty to ninety percent of your avocados scarred by greenhouse thrips. However, such serious infestations are not very widespread. You in the more interior areas may be wondering what we have in the way of insect pests on avocados in this state. We must not infer from this situation that the avocado is a tree that is inherently resistant to insect pests. The people who originally designed those emblems with which Messrs. Hardison and Haas who were honored today could tell you otherwise, because in the areas where the avocado is indigenous, such as in Mexico and Central and South America, they have a very serious condition with respect to avocado pests. We don't have them here because of the effectiveness of our quarantine program, in my estimation.
Acutaspis albopicta (Cockerell) is one of seven exotic scale species detected on shipments of'Hass' avocados entering California from Mexico. Here, we present the results of experiments to elucidate basic life history parameters of this species. The scale only reproduces sexually with unmated females producing no offspring. Unmated females survived up to 14 wk after settling on host fruits, whereas males survived for up to 62 h, with the majority dying within 46 h after emergence. Females laid a mean of 52.0 +/- 2.8 eggs (range, 5-171 eggs). Lower humidity (50%) was detrimental to the survival of male scales compared with high humidity (75%), especially during the pupal stage. The optimal temperature for development of both sexes was 25 degrees C. At this temperature, females developed from first instars to adults in approximately 28 d, whereas males emerged from their pupal cases after approximately 37 d. The adjusted lower developmental thresholds for females and males were 13.2 and 13.4 degrees C, respectively. The upper developmental threshold for both females and males was approximately 32 degrees C. Total development from first instar to adult female was 329 degree days and to emerged male, 433 degree days.
Brief descriptions are presented for 20 new species of Aphytis, along with notes on 8 new combinations and 2 new names.
Populations of the San Jose scale (SJS), Quadraspidiotus perniciosus (Comstock), and its parasitoids, Encarsia perniciosi (Tower) and Aphytis spp. were monitored with double-sided sticky tape and pheromone traps in an almond orchard. A total of 1.21 ha plots within the orchard were treated during winter dormancy with several insecticides, including horticultural mineral oil alone, oil combined with the organophosphate diazinon at different dilution rates, and oil combined with the pyrethroid esfenvalerate in a completely randomized block design. Higher volume diazinon applications (3750 and 1870 l ha -1 ) proved effective against SJS crawlers, as did esfenvalerate. The higher volume applications had greater deposition on Kromecoat ® cards placed in the top of the tree canopy, where SJS is most abundant. The lower-volume (935 l ha -1 ) application of diazinon provided control of first-generation crawlers similar to the other diazinon applications, but it was generally less effective in controlling subsequent generations. All insecticide treatments were associated with a reduction of parasitoid numbers, especially the esfenvalerate application.
1. Laboratory experiments and field studies were conducted to explain the coexistence of an endoparasitoid, Encarsia perniciosi Tower, and an ectoparasitoid, Aphytis melinus DeBach, both of which were introduced into California to control the California red scale, Aonidiella aurantii (Mask.).
2. Encarsia parasitized all scale stages but it preferred first and second instar scales. This is in contrast to Aphytis melinus, in which previous studies have shown that it parasitizes second and third instar females and second instar males but prefers third instar female scales. Encarsia developed most rapidly when it parasitized an early second instar and slowest when it parasitized the mature female scale. However, on early second instar scales it was about 80% as fecund as a wasp that emerged from a mature female scale.
3. Second instar scales parasitized by Encarsia were accepted by Aphytis as readily as unparasitized scales.
4. Encarsia did not distinguish between unparasitized hosts and those previously parasitized by Aphytis.
5. Encarsia always outcompeted by Aphytis when both species parasitize the same host.
6. Encarsia prefers scale on stems whereas Aphytis prefers those on leaves and fruits. This, too, may be a result of interspecific competition with Aphytis.
7. The partitioning of the scale resource by the two species explains why they coexist in coastal southern California but it does not explain why Encarsia disappeared from citrus groves in the inland valleys coincident with the introduction of Aphytis melinus into southern California.
Five closely related species of Encarsia, belonging to the luteola species-group, are analysed taxonomically using morphological and molecular techniques. Four of these belong to the meritoria-complex, and all species have a complicated taxonomic history of repeated misidentification and confusion. Morphological analysis is focused on morphometric characters of the female antennae using principal component and canonical discriminant analyses. DNA sequence data for the D2 region of 28S nuclear ribosomal genes were obtained for 13 populations of the luteola-group, with a further seven population sequences being obtained from GenBank. The combination of morphological and molecular study enables us to resolve the complex to a large extent, and to correct the previous confusion surrounding this group of species. Two species —E. californica and E. dispersa— are described as new. A proposal to place E. brasiliensis (Hempel) in synonymy with E. hispida DeSantis (the more recently described taxon) is presented. A lectotype is designated for E. haitiensis Dozier. Diagnoses or descriptions, and illustrations, of all included species are provided to facilitate the identification of females belonging to this complex. All known data concerning hosts and geographical distribution are presented.
The polymerase chain reaction (PCR) revolutionized the field of diagnostics, and today it has routine applications in medical, veterinary, forensic and botanical sciences. The fields of biological control and insect pest management have generally been slow to adopt PCR-based diagnostics in comparison with other fields of science. However, there has been increasing interest in the use of molecular diagnostic tools in arthropod biological control. In applied entomology, molecular techniques have generally been used for insect identification and systematics; however, PCR-based techniques are increasingly becoming recognized as valuable tools in ecological studies. Here, we review research that has used PCR-based techniques for parasitoid and predator/prey identification and detection, and place these studies in the context of their contributions to biological control of arthropods. The status and future directions of diagnostic molecular markers in applied entomology and insect pest management are also discussed.
Approximately 460 base pairs (bp) of DNA sequence that included the second internal transcribed spacer (ITS2) and some flanking 5.8S and 28S ribosomal RNA coding regions were compared between the two closely related and morphologically indistinguishable mosquito species Anopheles freeborni and A. hermsi and a third related species, A. occidentalis. Sequences were determined from 14 clones of polymerase chain reaction (PCR)-amplified DNA obtained from four colonies of A. freeborni, two colonies of A. hermsi, and one individual A. occidentalis. Four clones showed independent single bp differences from the consensus for the relevant species. Eleven sites differed between the consensus sequences of A. hermsi and A. freeborni; 28 sites differed between A. hermsi and A. occidentalis. With the exception of a single bp mismatch in the 5.8S and two single bp mismatches near the undetermined junction of the ITS2 and 28S regions, all differences were confined to the ITS2 region. A PCR-based species-diagnostic assay for the cryptic species A. hermsi and A. freeborni was developed; it uses four synthetic oligonucleotides, two derived from areas of interspecies sequence difference in the ITS2, and two derived from highly conserved regions in the flanking coding sequences. Small amounts of mosquito DNA amplified in the presence of these four primers produce fragments of diagnostic size for each species: 900 bp for A. freeborni, 350 bp for A. hermsi, and approximately 1.2-1.4 kb for various other Anopheles species tested. We believe that this general approach to the development of species-diagnostic assays can be extended easily to other complexes of closely related, morphologically indistinguishable species.
The phylogeny of the cryptic species complex of wasps in the genus Nasonia was inferred by analysis of nucleotide sequences of an rDNA internal transcribed spacer (ITS2) and the D2 region of 28S rDNA. Phylogenetic analysis showed that N. vitripennis descended from a theoretical common ancestor with that of a lineage that diverged into N. longicornis and N. giraulti. Differences in the ITS2 regions clearly distinguished two strains of N. giraulti. Another member of the Dibrachys Group, Trichomalopsis dubius, was placed outside of the Nasonia complex. The D2 region had a base substitution rate approximately 2 times slower than the ITS2 region and was used to resolve the phylogenetic affiliation of an eulophid, Melittobia digitata, to the pteromalids. Tree topology of the Nasonia complex was congruent with the phylogeny of a cluster of Wolbachia bacteria which infect these insects. The possible role of these bacteria in driving speciation is discussed.
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