The citrus leafminer, Phyllocnistis citrella, is a global pest of citrus. Damage is caused by larval mining of the leaves that reduces photosynthetic capacity of the leaves and predisposes the wounded leaf to infection by the bacterium that causes citrus canker disease. This entry in the encylopedia...
The citrus leafminer, Phyllocnistis citrella Stainton, is a major pest of citrus throughout the world due to leafmining damage that reduces photosynthetic capacity of leaves and increases the incidence and severity of citrus canker disease. A lure comprised of two aldehyde compounds isolated from ph...
The leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is a global pest of citrus and contributes to the incidence and severity of citrus bacterial canker, Xanthomonas axonopodis pv. citri. SPLAT-CLM™ (ISCA Technologies)is an emulsified wax product that provides sustained rele...
The sex pheromone of the citrus leafminer, Phyllocnistis citrella, was deployed in a Florida citrus grove using a novel deployment device containing SPLAT™, a flowable formulation of an emulsified wax compound designed to provide slow release of semiochemicals. The device consisted of two disks con...
Citrus canker (caused by Xanthomonas citri subsp. citri, Xcc) is an important bacterial disease of citrus that is spread naturally by rain and wind. Damage to citrus leaves by the citrus leafminer (CLM) , Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), has been shown to promote infect...
Citrus leafminer, Phyllocnistis citrella, is a major world wide pest of citrus. Mating disruption has proven effective against this pest in small plot investigations. We achieved season-long disruption of P. citrella with a newly developed, flowable emulsified wax dispenser of pheromone (SPLAT-CLM™...
Attraction of a native Florida leafminer, Phyllocnistis insignis (Lepidoptera: Gracillariidae), to pheromone of invasive citrus leafminer, P. citrella: Evidence for mating disruption of a native nontarget species
We collected a native North American species, Phyllocnistis insignis (Frey & Boll), in traps baited with a 3:1 blend of (Z,Z,E)-7,11,13-hexadecatrienal (triene) and (Z,Z)-7,11-hexadecadienal (diene), two components of the sex pheromone of the exotic citrus leafminer, Phyllocnistis citrella Stainton....
Recent efforts to disrupt mating of the leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), a global pest of citrus, have focused on the use of SPLAT™ (ISCA Technologies), a flowable wax emulsion intended to serve as a slow-release matrix for pheromones. Early success with this...
We collected a native North American species, Phyllocnistis insignis (Frey & Boll) (Lepidoptera: Gracillariidae), in traps baited with a 3:1 blend of (Z,Z,E)-7,11,13-hexadecatrienal (triene) and (Z,Z)-7,11-hexadecadienal (diene), 2 components of the sex pheromone of the invasive citrus leafminer, P....
Goane, L; Casmuz, A; Salas, H; Willink, E; Mangeaud, A; Valladares, G
Studies on insect natural enemies and their effects on host populations are of immense practical value in pest management. Predation and parasitism on a citrus pest, the leafminer Phyllocnistis citrella Stainton, were evaluated by sampling over 3 years in four locations within a world leading lemon producing area in Northwest Argentina. Both mortality factors showed seasonal trends consistent across locations, with predation exerting earlier and more sustained pressure than parasitism, which showed wider seasonal variations. The dominant parasitoids, native Cirrospilus neotropicus and introduced Ageniaspis citricola, showed different seasonal trends: C. neotropicus was dominant in spring whereas A. citricola superseded it in autumn and winter. Although parasitism rates were relatively low, the native C. neotropicus revealed favourable features as potential control agent, by showing density-dependence, parasitism rates comparable with those of the specific A. citricola during part of the cycle, and earlier synchronization with the host. The study provides highly relevant information for a sustainable management of this worldwide pest, for which biological control is considered the best long-term option.
We captured male Phyllocnistis citrella Stainton in traps baited with pheromone in pastureland 1200 m west of a known source. The capture of males was correlated with northeast wind blowing from groves, suggesting males moved passively on wind currents from groves before navigating upwind toward phe...
Traps were deployed in a Florida citrus grove at various dates over the course of one year to describe the seasonal flight phenology of the leafminer Phyllocnistic citrella. To compensate for lure degradation, a correction factor was applied based on a regression model of relative lure efficiency, e...
The leafminer, Phyllocnistis citrella Stainton, reproduces on leaf flush during winter. Deployment of pheromone during winter could suppress moth populations in spring and summer more than a spring application alone. We tested the primary pheromone component of Phyllocnistis (P. citrella), (Z,Z,E)-7...
The leafminer Phyllocnistis citrella is a global pest of citrus and contributes to the incidence and severity of citrus bacterial canker, Xanthomonas axonopodis pv. citri. SPLAT-CLM™ (ISCA Technologies, Inc.) is an emulsified wax product that provides sustained release of (Z,Z,E)-7,11,13-hexadecatr...
Greve, Caroline; Redaelli, Luiza R
Phyllocnistis citrella Stainton is considered an important pest of citrus, causing both direct (reduction on the photosynthetic area) and indirect damage (facilitation of invasion by bacteria that cause citrus canker). The lack of information about the population dynamics of P. citrella, considering the cultivation systems and varieties grown in citrus orchards in Rio Grande do Sul, Brazil, motivated this study. It aimed to evaluate the seasonal variation of immature stages of P. citrella, from June 2002 to July 2003, in two orchards of Citrus sinensis, cv. 'Valencia', one maintained according to organic management principles and the other under conventional ones. Fortnightly samplings were carried out, being one shoot collected from each one of 27 randomly chosen plants. The leaves were analyzed for the presence of eggs, larvae, pupae and mines of P. citrella. Leafminer was recorded from October 2002 to April 2003 in the organic orchard, and from November 2002 to July 2003 in the conventional one. A relationship between population size and resource availability (young leaves) was observed. However, population establishment does not depend exclusively on the existence of resources, but also on suitable climatic conditions. This was evidenced by the absence of attacks on the first shooting, which began in late winter. Meteorological factors and resource availability as a whole explain about 64% and 53% of the observed variation in the population size of P. citrella, respectively in the organic and conventional orchards.
George, Anjitha; Rao, C N; Ghike, Sonali; Dhengre, Vijay
Foliar application of insecticides has been the most commonly followed practice to manage Phyllocnistis citrella Stainton in nurseries and flush leaves in citrus groves. Leaf dip bioassays were conducted against insecticides, viz., acephate 75SP, dimethoate 30EC, abamectin 1.9EC, fenvalerate 20EC, imidacloprid 17.8SL, and thiamethoxam 25WG, and were tested against P. citrella larvae for their susceptibility. Among six insecticides tested on second-instar P. citrella larvae collected from Nagpur mandarin/acid lime cultivars during 2013-2016, abamectin was the most toxic insecticide for the initial year (LC50 values ranged from 20.99 to 49.00 ppm), while dimethoate (LC50 of 36.57-160.95 ppm) and thiamethoxam (39.90-71.96 ppm) were consistently effective against P. citrella larvae for the rest of the period. Resistance ratio (RR) values calculated based on the baseline susceptible culture, viz., abamectin (1.24-2.33), acephate (1.03-2.31), fenvalerate (1.54-3.45), dimethoate(1.28-5.63), imidacloprid (1.29-8.64), and thiamethoxam (1.05-1.80), indicated that the current RR values were in low levels (RR < 10).
The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is a key pest in most citrus growing regions worldwide. Adult citrus leafminers oviposit primarily on young elongating flush of citrus as well as other Rutaceae and some ornamental plants. Larvae feed on the epiderm...
Citrus leafminer, Phyllocnistis citrella Stainton, is active throughout the year in Florida and reproduces on periodic leaf flush in winter. We tested mating disruption in mature grapefruit trees during winter and spring using SPLAT-CLM, an emulsified wax with prolonged release of the insect’s prima...
Pheromone studies often seek to identify an optimal response to continuously varied mixture components wherein proportionality of one component cannot be varied independently. Geometric designs were used to systematically and efficiently explore the experimental space defined by pheromone amount and...
Davis, Donald R; Wagner, David L
Four New World species of Phyllocnistis Zeller are described from serpentine mines in Persea (Family Lauraceae). Phyllocnistis hyperpersea,new species, mines the upper leaf surfaces of avocado, Persea americana Mill., and red bay, Persea borbonia (L.) Spreng. and ranges over much of the southeastern United States into Central America. Phyllocnistis subpersea,new species, mines the underside and occasionally upper sides of new leaves of Persea borbonia in southeastern United States. Phyllocnistis longipalpa, new species, known only from southern Florida also mines the undersides of new leaves of Persea borbonia. Phyllocnistis perseafolia,new species, mines both leaf surfaces and possibly fruits of Persea americana in Colombia, South America. As in all known species of Phyllocnistis, the early instars are subepidermal sapfeeders in young (not fully hardened) foliage, and the final instar is an extremely specialized, nonfeeding larval form, whose primary function is to spin the silken cocoon, at the mine terminus, prior to pupation. Early stages are illustrated and described for three of the species. The unusual morphology of the pupae, particularly the frontal process of the head, is shown to be one of the most useful morphological sources of diagnostic characters for species identification of Phyllocnistis. COI barcode sequence distances are provided for the four proposed species and a fifth, undescribed species from Costa Rica.
The application of synthetic sex pheromones to disrupt mating of agricultural pests can be an effective and environmentally friendly alternative to pesticide applications. Optimizing mating disruption by manipulating multiple and interrelated variables such as the distribution and number of pheromon...
Pheromone blends composed of one or more components are mixtures. Mixtures present a unique problem for experiment design when response (e.g., insect attraction to a blend) is a function of proportionality of the blend's components. In mixtures, the ingredients must total to a constant value. Prop...
Experimental designs developed to address mixtures are ideally suited for many areas of experimental biology including pheromone blend studies because they address the confounding of proportionality and concentration intrinsic to factorial and one-factor-at-a-time designs. Geometric multivariate des...
Sétamou, M; Rodriguez, D; Saldana, R; Schwarzlose, G; Palrang, D; Nelson, S D
The systemic neonicotinoid insecticide imidacloprid, Admire Pro, was applied to 3- and 4-yr-old nonbearing 'Rio Red' grapefruit, Citrus x paradisi Macfad., trees in 2006 and 2007, respectively, to determine its effects in the control of two major citrus pests, the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), and a citrus leafminer Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae). Young flush shoots were randomly collected weekly for 13 and 11 wk in 2006 and 2007, respectively, to determine the infestation levels and densities of immature stages of both Asian citrus psyllid and P. citrella. Additional flush shoot samples were collected in 2007 and titers of imidacloprid in leaf tissue were determined using an enzyme-linked immunosorbent assay. Soil application of imidacloprid significantly reduced the infestation levels and densities of both pests on flush shoots, starting from the second week post application. The effects of the neonicotinoid insecticide were similar in both years. Analysis of imidacloprid concentration in leaf tissue showed a gradual increase during the first 3 wk, and titers remained well above 200 ppb for 11 wk postapplication. Significant positive correlations were obtained between imidacloprid titers in leaf tissue and the percentage of control levels achieved for both pests. A high level of suppression of both P. citrella and Asian citrus psyllid populations on citrus trees was associated with imidacloprid titer in leaf tissue >200 ppb, which was reached 2 wk after soil treatment. Although soil application of imidacloprid did not provide rapid knockdown of Asian citrus psyllid and P. citrella populations, it resulted in chronic residues in leaf tissue and long-term suppression of both pests.
The leafminer Phyllocnistis citrella (Lepidoptera: Gracillariidae) is a global pest of citrus and contributes to the incidence and severity of citrus bacterial canker disease. Results of response surface models generated by mixture-amount experiments suggested that an off-ratio blend consisting of t...
Yang, Fei; Du, Yuzhou; Cao, Jingman; Huang, Fangneng
Liriomyza trifolii (Burgess), Liriomyza huidobrensis (Blanchard), and Liriomyza bryoniae (Kaltenbach), are three closely related and economically important leafminer pests in the world. This study examined the complete mitochondrial genomes of L. trifolii, L. huidobrensis and L. bryoniae, which were 16,141 bp, 16,236 bp and 16,183 bp in length, respectively. All of them displayed 37 typical animal mitochondrial genes and an A+T-rich region. The genomes were highly compact with only 60-68 bp of non-coding intergenic spacer. However, considerable differences in the A+T-rich region were detected among the three species. Results of this study also showed the two ribosomal RNA genes of the three species had very limited variable sites and thus should not provide much information in the study of population genetics of these species. Data generated from three leafminers' complete mitochondrial genomes should provide valuable information in studying phylogeny of Diptera, and developing genetic markers for species identification in leafminers.
Background Plants have evolved a complicated resistance system and exhibit a variety of defense patterns in response to different attackers. Previous studies have shown that responses of plants to chewing insects and phloem-feeding insects are significantly different. Less is known, however, regarding molecular responses to leafminer insects. To investigate plant transcriptome response to leafminers, we selected the leafminer Liriomyza huidobrensis, which has a special feeding pattern more similar to pathogen damage than that of chewing insects, as a model insect, and Arabidopsis thaliana as a response plant. Results We first investigated local and systemic responses of A. thaliana to leafminer feeding using an Affymetrix ATH1 genome array. Genes related to metabolic processes and stimulus responses were highly regulated. Most systemically-induced genes formed a subset of the local response genes. We then downloaded gene expression data from online databases and used hierarchical clustering to explore relationships among gene expression patterns in A. thaliana damaged by different attackers. Conclusions Our results demonstrate that plant response patterns are strongly coupled to damage patterns of attackers. PMID:23231622
Fenoglio, María S.; Salvo, Adriana; Estallo, Elizabet L.
Urbanisation may have detrimental effects on communities of parasitoids, affecting their species richness, abundance, and species dominance. Here we investigated the influence of the degree of urbanisation on parasitoid communities of Liriomyza commelinae (Frost) (Diptera: Agromyzidae), a leafminer of Commelina erecta L. (Commelinaceae), in the city of Córdoba, Argentina. To study changes in species richness, the specific composition of parasitic complexes and their degree of impact on the leafminer, 18 sampling sites from the centre to the outskirts of the city were selected and different variables indicative of urbanisation were quantified in each site. During January and February of 2005 and 2006, all mined leaves found in each plant patch were collected and the following variables were estimated: proportion of mined patches, abundance of the leafminer, total parasitoid species richness, total parasitism rates and parasitism due to the most abundant parasitoid species. The percentage of mined patches and leafminer abundance increased with urbanisation degree. Estimates of parasitoid species richness were not influenced by urbanisation degree but increased with species richness of mined plants. Changes in the specific composition of species along the urbanisation gradient were observed. Although parasitism by one of the species studied was higher in more urbanised sites of the city, the total parasitism rate of L. commelinae was not affected by urbanisation degree, species richness of mined plants or leafminer abundance. It appears that urbanisation benefits the herbivore species here studied but not through altering parasitoid activity. Changes in parasitoid community composition reflex dissimilar tolerance to environmental conditions displayed by different parasitoid species.
Liriomyza huidobrensis is a highly destructive invasive leafminer pest currently causing extensive damage to vegetable and horticultural crops around the world. Liriomyza langei is a leafminer pest native to California that cannot currently be morphologically distinguished from L. huidobrensis. This...
Klug, T; Meyhöfer, R; Kreye, M; Hommes, M
In spite of the fact that since the end of the eighties, the horse chestnut leafminer, Cameraria ohridella, has established itself throughout Europe, native predators such as ants and birds are not attuned to this neozoic species. In contrast, several parasitic wasp species already started to exploit the invasive horse chestnut leafminer, but until now parasitation rates are quite low, mainly because of asynchrony in the lifecycles of parasitoids and host. Only the removal of leaf litter, in which pupae hibernate, is at the moment a strategy to reduce the infestation level in the next year. Unfortunately, not only hibernating horse chestnut leafminers but also parasitoids are removed, and important resources for biocontrol are unused. In the current study, we investigated the potential efficiency of the horse chestnut leafminer parasitoid complex extracted from leaf litter in defined environments. Parasitoids were released at different densities to investigate density dependence in parasitation rates. Although seven different species were released in our experiments, only Pnigalio agraules turned out to be responsible for biocontrol of C. ohridella. We recorded parasitation rates of up to 35%. Overall, parasitation rates were independent of the leafminer density but increased fourfold if ten times more parasitoid individuals were released. Unfortunately, none of the parasitoid species could be established in the experimental units in the long run. Results are compared to other parasitoid-leafminer systems, and promotion of horse chestnut leafminer parasitoids to support natural selection and biological control of the horse chestnut leafminer is discussed.
Hernández, Ricardo; Harris, Marvin; Liu, Tong-Xian
Liriomyza leafminers (Diptera: Agromyzidae) are cosmopolitan, polyphagous pests of horticultural plants and many are resistant to insecticides. Producers in South Texas rely on insecticides as the primary management tool for leafminers, and several compounds are available. The objective of this study is to address the efficacy of these compounds for controlling Liriomyza while minimizing their effects against natural enemies. Research plots were established at Texas AgriLife research center at Weslaco, Texas in fall 2007 and spring 2008 seasons, and peppers were used as a model crop. Plots were sprayed with novaluron, abamectin, spinetoram, lambda-cyhalothrin and water as treatments according to leafminer infestation; insecticide efficacy was monitored by collecting leaves and infested foliage. Plant phenology was also monitored. Novaluron was the most effective insecticide and lambda-cyhalothrin showed resurgence in leafminer density in fall 2007 and no reduction in spring 2008. Other compounds varied in efficacy. Novaluron showed the least number of parasitoids per leafminer larva and the lowest parasitoid diversity index among treatments followed by spinetoram. Liriomyza trifolii (Burgess) was the sole leafminer species on peppers, and 19 parasitoid species were found associated with this leafminer. Application of these insecticides for management of leafminers with conservation of natural enemies is discussed. PMID:21864155
Hernández, Ricardo; Harris, Marvin; Liu, Tong-Xian
Liriomyza leafminers (Diptera: Agromyzidae) are cosmopolitan, polyphagous pests of horticultural plants and many are resistant to insecticides. Producers in South Texas rely on insecticides as the primary management tool for leafminers, and several compounds are available. The objective of this study is to address the efficacy of these compounds for controlling Liriomyza while minimizing their effects against natural enemies. Research plots were established at Texas AgriLife research center at Weslaco, Texas in fall 2007 and spring 2008 seasons, and peppers were used as a model crop. Plots were sprayed with novaluron, abamectin, spinetoram, lambda-cyhalothrin and water as treatments according to leafminer infestation; insecticide efficacy was monitored by collecting leaves and infested foliage. Plant phenology was also monitored. Novaluron was the most effective insecticide and lambda-cyhalothrin showed resurgence in leafminer density in fall 2007 and no reduction in spring 2008. Other compounds varied in efficacy. Novaluron showed the least number of parasitoids per leafminer larva and the lowest parasitoid diversity index among treatments followed by spinetoram. Liriomyza trifolii (Burgess) was the sole leafminer species on peppers, and 19 parasitoid species were found associated with this leafminer. Application of these insecticides for management of leafminers with conservation of natural enemies is discussed.
Shi, Ainong; Mou, Beiquan
Leafminer (Liriomyza langei) is a major insect pest of many important agricultural crops, including spinach (Spinacia oleracea). Use of genetic resistance is an efficient, economic, and environment-friendly method to control this pest. The objective of this research was to conduct association analysis and identify single nucleotide polymorphism (SNP) markers associated with leafminer resistance in spinach germplasm. A total of 300 USDA spinach germplasm accessions were used for the association analysis of leafminer resistance. Genotyping by sequencing (GBS) was used for genotyping and 783 SNPs from GBS were used for association analysis. The leafminer resistance showed a near normal distribution with a wide range from 1.1 to 11.7 stings per square centimeter leaf area, suggesting that the leafminer resistance in spinach is a complex trait controlled by multiple genes with minor effect in this spinach panel. Association analysis indicated that five SNP markers, AYZV02040968_7171, AYZV02076752_412, AYZV02098618_4615, AYZV02147304_383, and AYZV02271373_398, were associated with the leafminer resistance with LOD 2.5 or higher. The SNP markers may be useful for breeders to select plants and lines for leafminer resistance in spinach breeding programs through marker-assisted selection.
DNA barcoding revealed the presence of the polyphagous leafminer pest Liriomyza sativae Blanchard in Bangladesh. DNA barcode sequences for mitochondrial COI were generated for Agromyzidae larvae, pupae and adults collected from field populations across Bangladesh. BLAST sequence similarity searches ...
Abe, Hiroshi; Tateishi, Ken; Seo, Shigemi; Kugimiya, Soichi; Hirai, Masami Yokota; Sawada, Yuji; Murata, Yoshiyuki; Yara, Kaori; Shimoda, Takeshi; Kobayashi, Masatomo
Here, we analyzed the interaction between Arabidopsis (Arabidopsis thaliana) and the American serpentine leafminer (Liriomyza trifolii), an important and intractable herbivore of many cultivated plants. We examined the role of the immunity-related plant hormone jasmonate (JA) in the plant response and resistance to leafminer feeding to determine whether JA affects host suitability for leafminers. The expression of marker genes for the JA-dependent plant defense was induced by leafminer feeding on Arabidopsis wild-type plants. Analyses of JA-insensitive coi1-1 mutants suggested the importance of JA in the plant response to leafminer feeding. The JA content of wild-type plants significantly increased after leafminer feeding. Moreover, coi1-1 mutants showed lower feeding resistance against leafminer attack than did wild-type plants. The number of feeding scars caused by inoculated adult leafminers in JA-insensitive coi1-1 mutants was higher than that in wild-type plants. In addition, adults of the following generation appeared only from coi1-1 mutants and not from wild-type plants, suggesting that the loss of the JA-dependent plant defense converted nonhost plants to accessible host plants. Interestingly, the glucosinolate-myrosinase defense system may play at most a minor role in this conversion, indicating that this major antiherbivore defense of Brassica species plants probably does not have a major function in plant resistance to leafminer. Application of JA to wild-type plants before leafminer feeding enhanced feeding resistance in Chinese cabbage (Brassica rapa), tomato (Solanum lycopersicum), and garland chrysanthemum (Chrysanthemum coronarium). Our results indicate that JA plays an important role in the plant response and resistance to leafminers and, in so doing, affects host plant suitability for leafminers.
Abe, Hiroshi; Tateishi, Ken; Seo, Shigemi; Kugimiya, Soichi; Hirai, Masami Yokota; Sawada, Yuji; Murata, Yoshiyuki; Yara, Kaori; Shimoda, Takeshi; Kobayashi, Masatomo
Here, we analyzed the interaction between Arabidopsis (Arabidopsis thaliana) and the American serpentine leafminer (Liriomyza trifolii), an important and intractable herbivore of many cultivated plants. We examined the role of the immunity-related plant hormone jasmonate (JA) in the plant response and resistance to leafminer feeding to determine whether JA affects host suitability for leafminers. The expression of marker genes for the JA-dependent plant defense was induced by leafminer feeding on Arabidopsis wild-type plants. Analyses of JA-insensitive coi1-1 mutants suggested the importance of JA in the plant response to leafminer feeding. The JA content of wild-type plants significantly increased after leafminer feeding. Moreover, coi1-1 mutants showed lower feeding resistance against leafminer attack than did wild-type plants. The number of feeding scars caused by inoculated adult leafminers in JA-insensitive coi1-1 mutants was higher than that in wild-type plants. In addition, adults of the following generation appeared only from coi1-1 mutants and not from wild-type plants, suggesting that the loss of the JA-dependent plant defense converted nonhost plants to accessible host plants. Interestingly, the glucosinolate-myrosinase defense system may play at most a minor role in this conversion, indicating that this major antiherbivore defense of Brassica species plants probably does not have a major function in plant resistance to leafminer. Application of JA to wild-type plants before leafminer feeding enhanced feeding resistance in Chinese cabbage (Brassica rapa), tomato (Solanum lycopersicum), and garland chrysanthemum (Chrysanthemum coronarium). Our results indicate that JA plays an important role in the plant response and resistance to leafminers and, in so doing, affects host plant suitability for leafminers. PMID:24022267
Kemmochi, T; Fujimori, S; Saito, T
The koinobiont parasitoid Halticoptera circulus (Walker) is a potential biological control agent of leafminers, but it has only rarely been collected from the invasive leafminer, Liriomyza trifolii (Burgess), in Japan. To understand why this is the case, parasitism and development of H. circulus in L. trifolii was compared with parasitism and development in two indigenous leafminer species, Liriomyza chinensis Kato and Chromatomyia horticola (Goureau). There was no significant difference in parasitism rates by H. circulus in the three leafminer species and the eggs and larvae successfully developed in L. chinensis and C. horticola. However, H. circulus failed to develop in L. trifolii, where developmental stages were encapsulated by host haemocytes. This parasitoid may be a good agent to control indigenous leafminers such as L. chinensis and C. horticola but is unlikely to be useful for the biological control of the invasive L. trifolii in Japan.
Foba, C N; Salifu, D; Lagat, Z O; Gitonga, L M; Akutse, K S; Fiaboe, K K M
Liriomyza leafminers (Diptera: Agromyzidae) are severe pests of vegetables and ornamentals worldwide. Previous studies revealed low leafminer parasitism across different agroecological zones in Kenya. The present paper reports on the composition of leafminer parasitoids at different elevations, in different seasons, and on different host crops. Surveys were conducted monthly from January to November 2012, and nine parasitoid species were recovered. Total mean parasitism in the study sites was 31.23 ± 1.03% from a total of 20 different vegetable Liriomyza-infested crops belonging to seven families. Diglyphus isaea (Walker) (Hymenoptera: Eulophidae), Phaedrotoma scabriventris, a newly released parasitoid, and Opius dissitus Muesebeck (Hymenoptera: Braconidae) were the most abundant at all elevations, accounting for 67.3, 18.6, and 9.2% of total parasitoids, respectively. Elevation, season, and host crop significantly affected the parasitoid species present and their abundance. Diglyphus isaea was more abundant at the high- and mid-elevations at all seasons compared with the low-elevation, whereas the lower-elevation favored higher abundance of P. scabriventris and O. dissitus during the long rainy season compared with the high- and mid-elevations at all seasons. Of all the host crops surveyed, parasitoids were more abundant on tomato, local kidney bean, snow pea and French bean than other crops. The total parasitism rate observed in this study suggests a considerable improvement in leafminer parasitism compared with previous surveys in Kenya. The implications of these findings for leafminer management in vegetable and ornamental production in Kenya are discussed.
Liriomyza sativae Blanchard, L. trifolii (Burgess) and L. huidobrensis (Blanchard) are three invasive leafminer species (Diptera: Agromyzidae) in China that have caused significant economic damage on vegetables and ornamental plants. In the current study, the repellent responses of female adults to ...
Closely related invasive species may often displace one another, but it is often difficult to determine mechanisms because of the historical nature of these events. The leafmining flies Liriomyza sativae and Liriomyza trifolii have become serious invasive agricultural pests throughout the world. W...
Leafminer (Liriomyza spp.) is a major insect pest of many important agricultural crops, including spinach (Spinacia oleracea). Use of genetic resistance is an efficient, economic and environment-friendly method to control this pest. The objective of this research was to conduct association analysis ...
Under field conditions, species displacements have occurred in different directions between the same invasive species of leafminers (Diptera: Agromyzidae). Liriomyza sativae (Blanchard) was displaced by L. trifolii (Burgess) in the western USA, with evidence suggesting that lower insecticide suscept...
Celin, E F; Oliveira, F I C; Dias-Pini, N S; Nunes, G H S; Aragão, F A S
Leafminers (Liriomyza sativae) are the main melon (Cucumis melo L.) pests in Northeast Brazil, which is the main region for the production and export of the fruit in Brazil. Of the integrated management strategies available, genetic resistance is the best method of preventing damage by these insects. The aim of this study was to select sources of resistance to leafminers in melon germplasm. Seven experiments were conducted in the laboratory, field, and greenhouse, with and without choice, using 52 melon accessions and 4 commercial hybrids as controls. Genetic variability among the accessions made it possible to select four new sources of resistance: 'CNPH 11-1072' and 'CNPH 11-1077', because they exhibited lower levels of infestation by the insect (antixenosis); and 'CNPH 00-915(R)' and 'BAGMEL 56(R)', because the pest larvae died soon after beginning to feed on the leaf mesophyll (antibiosis).
Gao, Yulin; Reitz, Stuart R.; Wei, Qingbo; Yu, Wenyan; Zhang, Zhi; Lei, Zhongren
Liriomyza sativae and L. trifolii are highly invasive leafminer pests of vegetable crops that have invaded southern China in recent years. Liriomyza sativae was the first of these species to invade China, but it is now being displaced by L. trifolii. The rate and extent of this displacement vary across southern China. In Hainan, monocultures of highly valuable cowpea are planted and treated extensively with insecticides in attempts to control leafminer damage. In Guangdong, cowpea fields are interspersed with other less valuable crops, such as towel gourd (Luffa cylindrica), which receive significantly fewer insecticide applications than cowpea. To determine how differences in cropping systems influence the Liriomyza species composition, we conducted field trials in 2011 and 2012 in Guangdong where both species were present. We replicated conditions in Hainan by planting cowpea monocultures that were isolated from other agricultural fields, and we replicated conditions in Guangdong by planting cowpea in a mixed crop environment with towel gourd planted in neighboring plots. We then compared leafminer populations in cowpea treated with the insecticide avermectin and untreated cowpea. We also monitored leafminer populations in the untreated towel gourd. Untreated cowpea and towel gourd had comparatively low proportions of L. trifolii, which remained relatively stable over the course of each season. Avermectin applications led to increases in the proportions of L. trifolii, and after three weekly applications populations were >95% L. trifolii in both crop systems. However, the rate of change and persistence of L. trifolii in the mixed crop system were less than in the monocrop. These results indicate that L. trifolii is much less susceptible to avermectin than is L. sativae. Further, L. sativae was able to persist in the untreated towel gourd, which probably enabled it to recolonize treated cowpea. PMID:24651465
Chen, Bing; Kang, Le
Latitudinal patterns for quantitative traits in insect are commonly used to investigate climatic adaptation. We compare the cold resistance of the leafminer (Liriomyza sativae) pupa among populations distributed from tropical to temperate regions, incorporating the thermal overwintering limit of the insect's range. The patterns of cold resistance for northern and southern populations differ. The southern populations significantly increased their cold resistance with latitude, showing a latitudinal pattern independent of seasons, acclimation regimes, and assay methods. In contrast, the northern populations showed no stable patterns; they were always intermediate in cold hardiness between the low-latitude and high-latitude populations within the overwintering limit. Integration of these data with those of the biologically similar congeneric leafminer, L. huidobrensis, suggests that a pattern shift in stress tolerance associated with the overwintering range limit is probably a general adaptive strategy adopted by freeze-intolerant species that have a high-latitude boundary of distribution, but can only overwinter and develop in protected greenhouses in harsh seasons. Considering the widespread availability of greenhouses for overwintering insects in northern China, we speculated that the large-scale existence of thermally-buffered microhabitats in greenhouses might eliminate the development of cold resistance of the leafminer populations. However, results suggest a strong selection for increased cold resistance for natural populations of Liriomyza species at higher latitudes that can overwinter in the field, but not for populations at latitudes above the thermal limit. Thus, habitat modification associated with greenhouses can limit gene flow and reduce cold tolerances even at latitudes above where the leafminers can overwinter in the field.
Gao, Yulin; Lei, Zhongren; Abe, Yoshihisa; Reitz, Stuart R
Under field conditions, species displacements have occurred in different directions between the same invasive species of leafminers (Diptera: Agromyzidae). Liriomyza sativae (Blanchard) was displaced by L. trifolii (Burgess) in the western United States, with evidence suggesting that lower insecticide susceptibility of L. trifolii is a factor. However, in Japan, the opposite has occurred, as L. trifolii was recently displaced by L. sativae. This displacement is probably because of the higher fecundity of L. sativae and differential effects of parasitoids on the two leafminer species. Here, we carried out long-term surveys of these same two invasive leafminer species during January through March in 1999, 2007, and 2011, as well as June through July in 2011, in eight locations (Sanya, Dongfang, Haikou, Leidong, Lingshui, Wuzhisan, Qionghai, and Danzhou) across Hainan Island of southern China. Our results indicate that, between 2007 and 2011, L. trifolii rapidly replaced L. sativae as the predominant leafminer of vegetables on Hainan Island, similar to the situation in the western United States. Further surveys of growers revealed that avermectins and cyromazine are the two most frequently used insecticides against leafminers on Hainan Island. Dose-mortality tests showed that L. trifolii populations from Hainan Island are less susceptible to avermectins and cyromazine compared with L. sativae populations. This lower insecticide susceptibility of L. trifolii may be associated with the displacement of L. sativae by L. trifolii, although additional ecological or environmental factors cannot be ruled out.
Bjorksten, Tracey A; Robinson, Michelle
The pest leafminers Liriomyza huidobrensis (Blanchard), Liriomyza sativae (Blanchard), and Liriomyza trifolii (Burgess) (Diptera: Agromyzidae) have spread into South East Asia and Oceania, and they are likely to reach Australia in the near future. Two translaminar pesticides, cyromazine and abamectin, currently provide effective chemical control of these pests, but because parasitoids can play an important role in controlling and preventing leafminer outbreaks, understanding the impact of pesticides on leafminer parasitoids is vital. Here, we tested larval and pupal mortality and sublethal effects of abamectin, cyromazine, and the widely used fungicide mancozeb on two common Australian leafminer parasitoids, Hemiptarsenus varicornis (Girault) and Diglyphus isaea (Walker). Abamectin caused significant mortality to larvae and pupae of both parasitoid species but cyromazine and mancozeb did not. Progeny production and longevity of H. varicornis were not affected by adult exposure to cyromazine and mancozeb, nor did direct pupal exposure decrease number of progeny produced by either parasitoid. Mortality of H. varicornis females emerging from leaves treated with abamectin was high for up to 72 h after eclosion but those surviving beyond 72 h did not differ from control females in the number of progeny produced. Mancozeb did not influence leaf residence time or parasitism by H. varicornis females. Cyromazine and the fungicide mancozeb were concluded to be compatible with the parasitoids tested and suitable for integrated pest management of leafminers should outbreaks of pest species occur in Australia. Abamectin should be used with caution because it caused significant mortality in both parasitoids tested here.
Scheffer, Sonja J; Lewis, Matthew L; Gaimari, Stephen D; Reitz, Stuart R
Liriomyza huidobrensis (Blanchard) is a highly destructive invasive leafminer pest currently causing extensive damage to vegetable and horticultural crops around the world. Liriomyza langei Frick is a leafminer pest native to California that cannot currently be morphologically distinguished from L. huidobrensis. We used a DNA-barcoding approach, a published PCR-RFLP method, and a new multiplex PCR method to analyze 664 flies matching the morphological description of huidobrensis-langei. We found no evidence for the presence of L. huidobrensis in our extensive samples from California. In addition to the new molecular method, this work is important because it provides definitive data that the California "pea leafminer" is currently, and has probably always been, L. langei. These data will also be important in the event that the highly invasive L. huidobrensis ever becomes established.
Valladares, Graciela; Salvo, Adriana
We examined the temporal community dynamics of leafminers (Agromyzidae: Diptera) and their mainly polyphagous parasitoids in a natural habitat from Central Argentina. Changes in community composition are shown by changes in dominant species and similarity coefficients. Abundance of leafminers was highest in winter, and was not related to their species richness. Abundance and species richness were correlated in the parasitoid community. Temporal variation in parasitoid diversity and abundance were positively correlated with species number and density in the host community. Apparent parasitism was greater when parasitoid species richness was high and parasitoid community dominance was low.
Lundquist, J E; Reich, R M; Tuffly, M
The amber-marked birch leafminer (Profenusa thomsoni [Konow]) (Hymenoptera: Tenthredinidae) has caused severe infestations of birch species in Anchorage, AK, since 2002. Its spatial distribution has been monitored since 2006 and summarized using interpolated surfaces based on simple kriging. Results indicate that this insect pest is unevenly distributed, occurring in multineighborhood sized patches that migrate from year to year. Patches showing heavy infestation one year are followed by light infestations the following year. In this study, we developed methods of assessing and describing spatial distributions of P. thomsoni as they vary from year to year, and speculate on potential causes of these trends in landscape patterns.
Stonis, Jonas R; Diškus, Arūnas; Remeikis, Andrius
First Liabum Adans. (Asteraceae) feeding Nepticulidae are reported. Two new new species from the Andes (Ecuador) are described: Stigmella serpantina Diškus & Stonis, sp. nov. and S. pangorica Diškus & Stonis, sp. nov. The male genitalia of both species and the female genitalia, as well the leaf-mines of S. serpantina sp. nov. are illustrated.
The Agricultural Research Service, United States Department of Agriculture announces the release of a breeding line of green leaf lettuce (Lactuca sativa L.) with resistance to leafminers (Liriomyza langei Frick) and lettuce mosaic. The line MU06-857 is similar to cultivar ‘Lolla Rossa’ (‘Lollo Ros...
Diškus, Arūnas; Stonis, Jonas R
This paper describes Astrotischeria neotropicana Diškus & Stonis, sp. nov. (Lepidoptera: Tischeriidae), a new leaf-miner on Sida (Malvaceae) with a broad distribution range in tropical Central & South America. The new species is currently recorded from the Amazon Basin in Peru and Ecuador to tropical lowlands in Guatemala and Belize (including the Caribbean Archipelago). The new species is illustrated with photographs of the adults, male and female genitalia, and the leaf-mines; distribution map is also provided.
Bawin, Thomas; De Backer, Lara; Dujeu, David; Legrand, Pauline; Caparros Megido, Rudy; Francis, Frédéric; Verheggen, François J.
The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a devastating pest that develops principally on solanaceous plants throughout South and Central America and Europe. In this study, we tested the influence of three levels of T. absoluta infestations on the attraction and oviposition preference of adult T. absoluta. Three infestation levels (i.e., non-infested plants, plants infested with 10 T. absoluta larvae, and plants infested with 20 T. absoluta larvae) were presented by pairs in a flying tunnel to groups of T. absoluta adults. We found no differences in terms of adult attraction for either level of infestations. However, female oviposition choice is influenced by larvae density on tomato plants. We discuss the underlying mechanisms and propose recommendations for further research. PMID:26462946
Chen, Bing; Kang, Le
Pupal SCP (supercooling point) of Liriomyza huidobrensis showed no variation with age, with an average of -20.9 degree C. Low temperature survival of different ages of pupae showed no correlation with their SCP. Nonlinear regression analysis found that the response of L. huidobrensis pupae to exposure time under different low temperature regimes above -5 degree C was best fitted by a logistic equation. Both low temperature and exposure time had significant effects on pupal mortality. Temperatures above 5 degree C do not prevent pupae from emergence. L. huidobrensis was shown to be a freeze susceptible, and at the same time, a chill tolerant insect. It can tolerate subzero temperatures by supercooling. Compared with L. sativae, another dominant leafminer in China, L. huidobrensis is more cold tolerant. Our results explain differences between the species in geographic distribution and phenology.
Gao, Yulin; Reitz, Stuart R.; Wei, Qingbo; Yu, Wenyan; Lei, Zhongren
Background Closely related invasive species may often displace one another, but it is often difficult to determine mechanisms because of the historical nature of these events. The leafmining flies Liriomyza sativae and Liriomyza trifolii have become serious invasive agricultural pests throughout the world. Where both species have invaded the same region, one predominates over the other. Although L. sativae invaded Hainan Island of China first, it recently has been displaced by the newly invasive L. trifolii. We hypothesized that differential susceptibilities to insecticides could be causing this demographic shift. Methodology/Principal Findings Avermectin and cyromazine are the most commonly used insecticides to manage leafminers, with laboratory bioassays demonstrating that L. trifolii is significantly less susceptible to these key insecticides than is L. sativae. In trials where similar numbers of larvae of both species infested plants, which subsequently were treated with the insecticides, the eclosing adults were predominately L. trifolii, yet similar numbers of adults of both species eclosed from control plants. The species composition was then surveyed in two regions where L. trifolii has just begun to invade and both species are still common. In field trials, both species occurred in similar proportions before insecticide treatments began. Following applications of avermectin and cyromazine, almost all eclosing adults were L. trifolii in those treatment plots. In control plots, similar numbers of adults of the two species eclosed, lending further credence to the hypothesis that differential insecticide susceptibilities could be driving the ongoing displacement of L. sativae by L. trifolii. Conclusions/Significance Our results show that differential insecticide susceptibility can lead to rapid shifts in the demographics of pest complexes. Thus, successful pest management requires the identification of pest species to understand the outcome of insecticide
Wagner, Diane; DeFoliart, Linda; Doak, Patricia; Schneiderheinze, Jenny
The aspen leaf miner, Phyllocnistis populiella, feeds on the contents of epidermal cells on both top (adaxial) and bottom (abaxial) surfaces of quaking aspen leaves, leaving the photosynthetic tissue of the mesophyll intact. This type of feeding is taxonomically restricted to a small subset of leaf mining insects but can cause widespread plant damage during outbreaks. We studied the effect of epidermal mining on aspen growth and physiology during an outbreak of P. populiella in the boreal forest of interior Alaska. Experimental reduction of leaf miner density across two sites and 3 years significantly increased annual aspen growth rates relative to naturally mined controls. Leaf mining damage was negatively related to leaf longevity. Leaves with heavy mining damage abscised 4 weeks earlier, on average, than leaves with minimal mining damage. Mining damage to the top and bottom surfaces of leaves had different effects on physiology. Mining on the top surface of the leaf had no significant effect on photosynthesis or conductance and was unrelated to leaf stable C isotope ratio (delta(13)C). Mining damage to the bottom leaf surface, where stomata are located, had significant negative effects on net photosynthesis and water vapor conductance. Percent bottom mining was positively related to leaf delta(13)C. Taken together, the data suggest that the primary mechanism for the reduction of photosynthesis by epidermal leaf mining by P. populiella is the failure of stomata to open normally on bottom-mined leaves.
Scheffer, S J; Wijesekara, A; Visser, D; Hallett, R H
A molecular method is presented for differentiating the morphologically cryptic leafminers Liriomyza langei Frick and L. huidobrensis (Blanchard). This method requires polymerase chain reaction (PCR) amplification of a 1031-bp region of mitochondrial cytochrome oxidase DNA followed by restriction fragment analysis using the restriction enzymes SpeI and EcoRV. Spel cuts the mitochondrial fragment of L. langei into two fragments, but does not cut the L. huidobrensis fragment. EcoRV cuts the L. huidobrensis fragment into two fragments, but does not cut the L. langei fragment. This PCR-restriction fragment-length polymorphism (RFLP) method is faster and less costly than DNA sequencing,which is currently the only other way to differentiate these two species. We apply the method to samples from recently introduced leafminer populations in Sri Lanka, Canada, and South Africa and find that the invasive leafminer in all three locations is L. huidobrensis.
Whiteman, Noah K.; Groen, Simon C.; Chevasco, Daniela; Bear, Ashley; Beckwith, Noor; Gregory, T. Ryan; Denoux, Carine; Mammarella, Nicole; Ausubel, Frederick M.; Pierce, Naomi E.
Experimental infections of Arabidopsis thaliana (Arabidopsis) with genomically characterized plant pathogens such as Pseudomonas syringae have facilitated dissection of canonical eukaryotic defense pathways and parasite virulence factors. Plants are also attacked by herbivorous insects, and the development of an ecologically relevant genetic model herbivore that feeds on Arabidopsis will enable the parallel dissection of host defense and reciprocal resistance pathways such as those involved in xenobiotic metabolism. An ideal candidate is Scaptomyza flava, a drosophilid fly whose leafmining larvae are true herbivores that can be found in nature feeding on Arabidopsis and other crucifers. Here we describe the eukaryotic life cycle of S. flava on Arabidopsis, and use multiple approaches to characterize the response of Arabidopsis to S. flava attack. Oviposition choice tests and growth performance assays on different Arabidopsis ecotypes, defense-related mutants, and hormone and chitin-treated plants revealed significant differences in host preference and variation in larval performance across Arabidopsis accessions. The jasmonate (JA) and glucosinolate pathways in Arabidopsis are important in mediating quantitative resistance against S. flava, and priming with JA or chitin resulted in increased resistance. Expression of xenobiotic detoxification genes was reduced in S. flava larvae reared on Arabidopsis JA signaling mutants, and increased in plants pre-treated with chitin. These results and future research directions are discussed in the context of developing a genetic model system to analyze insect/plant interactions. PMID:21073583
De Smedt, Caroline; Van Damme, Veerle; De Clercq, Patrick; Spanoghe, Pieter
(1) Background: The tomato leafminer Tuta absoluta (Lepidoptera: Gelechiidae) is a key tomato insect pest. At present, it is considered to be a serious threat in various countries in Europe, North Africa, and Middle East. The extensive use and the developed resistance of T. absoluta to spinosad causes some concern, which leads to the need for alternative products. (2) Materials and Methods: Several laboratory experiments were conducted to investigate the ovicidal properties of a zeolite particle film on T. absoluta. The toxicity of three different zeolites and six zeolite formulations to T. absoluta eggs and larvae was determined using different exposure methods. (3) Results: In general, the formulated zeolites yielded higher egg and larvae mortality values, especially when the zeolite particle film was residually applied. Notable differences in mortality rates from exposure to zeolites compared to other products, such as kaolin, its formulated product Surround, and the insecticide spinosad, were observed. Kaolin and Surround exhibited little or no effect for both application methods, while the hatch rate was reduced by 95% when spinosad was applied topically. Spinosad yielded egg and larvae mortality rates of 100% for both application methods. Additionally, increased oviposition activity was observed in adults exposed to the wettable powder (WP) formulations. These WP formulations increased egg deposition, while Surround and spinosad elicited a negative oviposition response. (4) Conclusions: It can be derived that the tested products, zeolites BEA (Beta polymorph A), FAU (Faujasite), LTA (Linde type A), and their formulations, had no real insecticidal activity against the eggs of T. absoluta. Nevertheless, egg exposure to zeolites seemed to affect the development process by weakening the first instar larvae and increasing their mortality. Subsequently, based on the choice test, no significant difference was observed between the number of eggs laid on the treated
Han, Peng; Lavoir, Anne-Violette; Le Bot, Jacques; Amiens-Desneux, Edwige; Desneux, Nicolas
This study examined the effects of various levels of nitrogen inputs (optimal, insufficient and excessive) and water inputs (optimal, low drought and high drought) to tomato plants (Solanum lycopersicum) on survival and development of an invasive tomato leafminer, Tuta absoluta (Meytick) (Lepidoptera: Gelechiidae). Plant growth i.e. plant height and the number of nodes declined under insufficient or excessive nitrogen treatment. Compared to optimal N, insufficient N treatment decreased leaf N content and increased the carbon/nitrogen ratio (C/N) whereas an excess of N had no effect on both leaf N content and leaf C/N ratio. Sub-optimal nitrogen supplies, water treatments and their interactions, significantly reduced the leafminer survival rate and slowed down its development. Together with the findings from three recent companion studies, we assumed that a combination of changes in nutritional value and chemical defense could explain these observed effects. Furthermore, our findings supported both the “Plant vigor hypothesis” and the “Nitrogen limitation hypothesis”. PMID:24675796
Tantowijoyo, Warsito; Hoffmann, Ary A
Changes in morphological traits along elevation and latitudinal gradients in ectotherms are often interpreted in terms of the temperature-size rule, which states that the body size of organisms increases under low temperatures, and is therefore expected to increase with elevation and latitude. However other factors like host plant might contribute to spatial patterns in size as well, particularly for polyphagous insects. Here elevation patterns for trait size and shape in two leafminer species are examined, Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae) and L. sativae Blanchard, along a tropical elevation gradient in Java, Indonesia. Adult leafminers were trapped from different locations in the mountainous area of Dieng in the province of Central Java. To separate environmental versus genetic effects, L. huidobrensis originating from 1378 m and 2129 m ASL were reared in the laboratory for five generations. Size variation along the elevation gradient was only found in L. huidobrensis and this followed expectations based on the temperature-size rule. There were also complex changes in wing shape along the gradient. Morphological differences were influenced by genetic and environmental effects. Findings are discussed within the context of adaptation to different elevations in the two species.
Huang, Li-Hua; Kang, Le
Studies have demonstrated differences in temperature tolerance between two Liriomyza species, L. huidobrensis and L. sativae. To investigate whether the heat shock proteins (Hsps) in the two species have different expression profiles during temperature stress, we cloned hsp90, 70, 60, 40 and 20, and analysed their expression profiles across temperature gradients by real-time quantitative PCR and Western blotting. The results revealed that the number of TATA-box-like elements and A/T-rich insertion/deletions within the 5' UTRs of the hsps are different in the two species. The temperatures for onset (T(on)) or maximal (T(max)) induction of hsp expression in L. huidobrensis were generally 2.5-10 degrees C lower than those in L. sativae, and the T(on) were highly consistent with the temperature limits of the northern boundary of the range of these two leafminer species. These studies confirmed, in terms of gene expression levels, that L. huidobrensis is more cold tolerant than L. sativae, which is more heat tolerant, and suggest that the T(on) (or T(max)) of hsps can represent the differences in temperature tolerance of these two leafminer species, and may be used to determine their natural geographical distribution limits.
Tantowijoyo, Warsito; Hoffmann, Ary A.
Changes in morphological traits along elevation and latitudinal gradients in ectotherms are often interpreted in terms of the temperature-size rule, which states that the body size of organisms increases under low temperatures, and is therefore expected to increase with elevation and latitude. However other factors like host plant might contribute to spatial patterns in size as well, particularly for polyphagous insects. Here elevation patterns for trait size and shape in two leafminer species are examined, Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae) and L. sativae Blanchard, along a tropical elevation gradient in Java, Indonesia. Adult leafminers were trapped from different locations in the mountainous area of Dieng in the province of Central Java. To separate environmental versus genetic effects, L. huidobrensis originating from 1378 m and 2129 m ASL were reared in the laboratory for five generations. Size variation along the elevation gradient was only found in L. huidobrensis and this followed expectations based on the temperature-size rule. There were also complex changes in wing shape along the gradient. Morphological differences were influenced by genetic and environmental effects. Findings are discussed within the context of adaptation to different elevations in the two species. PMID:21867436
Blacket, M J; Rice, A D; Semeraro, L; Malipatil, M B
Leafmining flies (Diptera: Agromyzidae) can be serious economic pests of horticultural crops. Some genera such as Liriomyza are particularly problematic with numerous species, some of which are highly polyphagous (wide host range), which can only be confidently identified morphologically from adult males. In our study, DNA barcoding was employed to establish new locality records of the vegetable leafminer fly, Liriomyza sativae, from the islands of Torres Strait (Queensland, Australia) and the central highlands of Papua New Guinea (PNG). These records represent significant range extensions of this highly invasive plant pest. Specimens of immature leafminers (from leaf mines) were collected over a 5-year period during routine plant health surveys in ethanol or on FTA® filter paper cards, both methods proved effective at preserving and transporting insect DNA under tropical conditions, with FTA cards possessing some additional logistical benefits. Specimens were identified through sequencing two sections of the cytochrome oxidase I gene and the utility of each was assessed for the identification of species and intra-specific genetic lineages. Our study indicates that multiple haplotypes of L. sativae occur in PNG, while a different haplotype is present in the Torres Strait, with genetic regionalization between these areas apart from a single possible instance - one haplotype 'S.7' appears to be common between these two regions - interestingly this has also been the most common haplotype detected in previous studies of invasive L. sativae populations. The DNA barcoding methods employed here not only identified multiple introductions of L. sativae, but also appear generally applicable to the identification of other agromyzid leafminers (Phytomyzinae and Agromyzinae) and should decrease the likelihood of potentially co-amplifying internal hymenopteran parasitoids. Currently, L. sativae is still not recorded from the Australian mainland; however, further sampling of
Mortensen, Brent; Wagner, Diane; Doak, Patricia
For many insect herbivores, maternal host selection is a critical determinant of offspring survival; however, maternal fitness is also affected by adult resources such as food availability. Consequently, adult resources may promote oviposition in sub-optimal locations when measured in terms of offspring performance. We tested whether oviposition site preference is primarily shaped by proximity to adult food resources or offspring performance in the aspen leaf miner (Phyllocnistis populiella). Quaking aspen (Populus tremuloides) produce extrafloral nectaries (EFNs) on a subset of their leaves. EFN expression on leaves is associated with decreased P. populiella damage and larval performance; however, P. populiella adults feed from EFNs. We reduced extrafloral nectar availability on entire aspen ramets and excluded crawling predators in a full factorial experiment at two sites in interior Alaska, USA. Patterns of egg deposition by P. populiella appeared to be primarily affected by offspring survival rather than adult resource availability. While oviposition was unaffected by nectar availability, adult moths laid fewer eggs on leaves with than without EFNs. By avoiding leaves with EFNs, moths increased offspring survival. Both moths and predators distinguished between leaves with and without EFNs even when nectar and visual cues were obscured, and therefore may respond to chemical cues associated with EFN expression.
Roditakis, Emmanouil; Steinbach, Denise; Moritz, Gerald; Vasakis, Emmanouil; Stavrakaki, Marianna; Ilias, Aris; García-Vidal, Lidia; Martínez-Aguirre, María Del Rosario; Bielza, Pablo; Morou, Evangelia; Silva, Jefferson E; Silva, Wellington M; Siqueira, Ηerbert A A; Iqbal, Sofia; Troczka, Bartlomiej J; Williamson, Martin S; Bass, Chris; Tsagkarakou, Anastasia; Vontas, John; Nauen, Ralf
Insect ryanodine receptors (RyR) are the molecular target-site for the recently introduced diamide insecticides. Diamides are particularly active on Lepidoptera pests, including tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae). High levels of diamide resistance were recently described in some European populations of T. absoluta, however, the mechanisms of resistance remained unknown. In this study the molecular basis of diamide resistance was investigated in a diamide resistant strain from Italy (IT-GELA-SD4), and additional resistant field populations collected in Greece, Spain and Brazil. The genetics of resistance was investigated by reciprocally crossing strain IT-GELA-SD4 with a susceptible strain and revealed an autosomal incompletely recessive mode of inheritance. To investigate the possible role of target-site mutations as known from diamondback moth (Plutella xylostella), we sequenced respective domains of the RyR gene of T. absoluta. Genotyping of individuals of IT-GELA-SD4 and field-collected strains showing different levels of diamide resistance revealed the presence of G4903E and I4746M RyR target-site mutations. These amino acid substitutions correspond to those recently described for diamide resistant diamondback moth, i.e. G4946E and I4790M. We also detected two novel mutations, G4903V and I4746T, in some of the resistant T. absoluta strains. Radioligand binding studies with thoracic membrane preparations of the IT-GELA-SD4 strain provided functional evidence that these mutations alter the affinity of the RyR to diamides. In combination with previous work on P. xylostella our study highlights the importance of position G4903 (G4946 in P. xylostella) of the insect RyR in defining sensitivity to diamides. The discovery of diamide resistance mutations in T. absoluta populations of diverse geographic origin has serious implications for the efficacy of diamides under applied conditions. The implementation of appropriate resistance
Winkler, Isaac S; Mitter, Charles; Scheffer, Sonja J
A central but little-tested prediction of "escape and radiation" coevolution is that colonization of novel, chemically defended host plant clades accelerates insect herbivore diversification. That theory, in turn, exemplifies one side of a broader debate about the relative influence on clade dynamics of intrinsic (biotic) vs. extrinsic (physical-environmental) forces. Here, we use a fossil-calibrated molecular chronogram to compare the effects of a major biotic factor (repeated shift to a chemically divergent host plant clade) and a major abiotic factor (global climate change) on the macroevolutionary dynamics of a large Cenozoic radiation of phytophagous insects, the leaf-mining fly genus Phytomyza (Diptera: Agromyzidae). We find one of the first statistically supported examples of consistently elevated net diversification accompanying shift to new plant clades. In contrast, we detect no significant direct effect on diversification of major global climate events in the early and late Oligocene. The broader paleoclimatic context strongly suggests, however, that climate change has at times had a strong indirect influence through its effect on the biotic environment. Repeated rapid Miocene radiation of these flies on temperate herbaceous asterids closely corresponds to the dramatic, climate-driven expansion of seasonal, open habitats.
van Nieukerken, Erik J.; Geertsema, Henk
Abstract A grapevine leafminer found recently in table grape orchards and vineyards in the Paarl region (Western Cape, South Africa) is described as Holocacista capensis sp. n. It has also been found on native Rhoicissus digitata and bred on that species in the laboratory. It is closely related to Holocacista salutans (Meyrick, 1921), comb. n. (from Antispila), described from Durban in KwaZulu-Natal, but widespread in southern Africa and a native leafminer of various Vitaceae: Rhoicissus tomentosa, Rhoicissus digitata, Rhoicissus tridentata and Cissus cornifolia. Holocacista capensis has been found on Vitis vinifera both in Gauteng and Western Cape, the earliest record being from 1950 in Pretoria. The initial host shift from native Vitaceae to Vitis must have occurred much earlier. The species is sometimes present in high densities, but hitherto no sizeable damage to the crops has been noted. The genus Holocacista Walsingham & Durrant, 1909, previously known from the single European grapevine leafminer Holocacista rivillei (Stainton, 1855), is expanded and redescribed and for the first time reported from Africa, East and South-East Asia and Australia. It comprises seven named species and at least 15 unnamed species. The following species are also recombined with Holocacista: transferred from Antispilina: South-African Holocacista varii (Mey, 2011), comb. n., feeding on Pelargonium, transferred from Antispila: the Indian species Holocacista micrarcha (Meyrick, 1926), comb. n. and Holocacista pariodelta (Meyrick, 1929), comb. n., both feeding on Lannea coromandelica, and Holocacista selastis (Meyrick, 1926), comb. n. on Psychotria dalzelii. We also remove the following from Antispila: Heliozela anna (Fletcher, 1920), comb. n. and Heliozela argyrozona (Meyrick, 1918), comb. n., whereas the following Indian Vitaceae feeding species are confirmed to belong in Antispila s. str.: Antispila argostoma Meyrick, 1916 and Antispila aristarcha Meyrick, 1916. Holocacista
Pre-release efficacy assessment of the leaf-mining moth Digitivalva delaireae (Lepidoptera: Glyphipterigidae), a potential biological control agent for Cape-ivy, Delairea odorata (Asteraceae), in western North America
The leaf-mining moth Digitivalva delaireae Gaedike & Kruger (Lepidoptera: Glyphipterigidae) is a potential biological control agent for the invasive vine Cape-ivy, Delairea odorata Lemaire (Asteraceae), in western North America, where two morphological varieties (stipulate and exstipulate) of Cape-i...
Wang, Haihong; Reitz, Stuart R.; Xiang, Juncheng; Smagghe, Guy; Lei, Zhongren
Liriomyza sativae and L. trifolii (Diptera: Agromyzidae) are two highly invasive species of leafmining flies, which have become established as pests of horticultural crops throughout the world. In certain regions where both species have been introduced, L. sativae has displaced L. trifolii, whereas the opposite has occurred in other regions. These opposing outcomes suggest that neither species is an inherently superior competitor. The regions where these displacements have been observed (southern China, Japan and western USA) are climatically different. We determined whether temperature differentially affects the reproductive success of these species and therefore if climatic differences could affect the outcome of interspecific interactions where these species are sympatric. The results of life table parameters indicate that both species can develop successfully at all tested temperatures (20, 25, 31, 33°C). L. sativae had consistently higher fecundities at all temperatures, but L. trifolii developed to reproductive age faster. Age-stage specific survival rates were higher for L. sativae at low temperatures, but these were higher for L. trifolii at higher temperatures. We then compared the net reproductive rates (R0) for both species in pure and mixed cultures maintained at the same four constant temperatures. Both species had significantly lower net reproductive rates in mixed species cultures compared with their respective pure species cultures, indicating that both species are subject to intense interspecific competition. Net reproductive rates were significantly greater for L. sativae than for L. trifolii in mixed species groups at the lower temperatures, whereas the opposite occurred at the higher temperature. Therefore, interactions between the species are temperature dependent and small differences could shift the competitive balance between the species. These temperature mediated effects may contribute to the current ongoing displacement of L. sativae by
Doorenweerd, Camiel; van Nieukerken, Erik J.; Menken, Steph B. J.
Background Host association patterns in Ectoedemia (Lepidoptera: Nepticulidae) are also encountered in other insect groups with intimate plant relationships, including a high degree of monophagy, a preference for ecologically dominant plant families (e.g. Fagaceae, Rosaceae, Salicaceae, and Betulaceae) and a tendency for related insect species to feed on related host plant species. The evolutionary processes underlying these patterns are only partly understood, we therefore assessed the role of allopatry and host plant family shifts in speciation within Ectoedemia. Methodology Six nuclear and mitochondrial DNA markers with a total aligned length of 3692 base pairs were used to infer phylogenetic relationships among 92 species belonging to the subgenus Ectoedemia of the genus Ectoedemia, representing a thorough taxon sampling with a global coverage. The results support monophyletic species groups that are congruent with published findings based on morphology. We used the obtained phylogeny to explore host plant family association and geographical distribution to investigate if host shifts and allopatry have been instrumental in the speciation of these leafmining insects. Significance We found that, even though most species within species groups commonly feed on plants from one family, shifts to a distantly related host family have occasionally occurred throughout the phylogeny and such shifts are most commonly observed towards Betulaceae. The largest radiations have occurred within species groups that feed on Fagaceae, Rosaceae, and Salicaceae. Most species are restricted to one of the seven global biogeographic regions, but within species groups representatives are commonly found in different biogeographic regions. Although we find general patterns with regard to host use and biogeography, there are differences between clades that suggest that different drivers of speciation, and perhaps drivers that we did not examine, have shaped diversity patterns in different
Giron, David; Huguet, Elisabeth; Stone, Graham N; Body, Mélanie
Gall-inducing insects are iconic examples in the manipulation and reprogramming of plant development, inducing spectacular morphological and physiological changes of host-plant tissues within which the insect feeds and grows. Despite decades of research, effectors involved in gall induction and basic mechanisms of gall formation remain unknown. Recent research suggests that some aspects of the plant manipulation shown by gall-inducers may be shared with other insect herbivorous life histories. Here, we illustrate similarities and contrasts by reviewing current knowledge of metabolic and morphological effects induced on plants by gall-inducing and leaf-mining insects, and ask whether leaf-miners can also be considered to be plant reprogrammers. We review key plant functions targeted by various plant reprogrammers, including plant-manipulating insects and nematodes, and functionally characterize insect herbivore-derived effectors to provide a broader understanding of possible mechanisms used in host-plant manipulation. Consequences of plant reprogramming in terms of ecology, coevolution and diversification of plant-manipulating insects are also discussed.
López, R; Carmona, D; Vincini, A M; Monterubbianesi, G; Caldiz, D
The leafminer Liriomyza huidobrensis Blanchard is considered a key pest for potatoes in Argentina. Population dynamics and leaf damage caused by the leafminer on seven selected potato processing varieties were assessed at Balcarce during the 2002 and 2003 growing seasons. Adult population dynamic was monitored using yellow sticky traps, while leaf damage (punctures and mines) was assessed using a damage index scale from low to severe. Liriomyza huidobrensis adults were present throughout the growing season and the population increased along crop development. The same was true for all varieties regarding larval damage, being low on early crop stages and severe late in the season. Varieties were grouped in two different categories according to damage scale index. Shepody, Kennebec, Frital and Innovator showed a higher damage index when compared with Santana, Ranger Russet and Russet Burbank, which exhibited a lower damage. Moreover, it could be assumed that damage was related to the foliage greenness, with light green colored varieties (Shepody, Kennebec, Frital and Innovator) being more attractive and affected by L. huidobrensis.
Foba, C N; Salifu, D; Lagat, Z O; Gitonga, L M; Akutse, K S; Fiaboe, K K M
A longitudinal study to identify the species of Liriomyza leafminer, their distribution, relative abundance, and seasonal variation, including their host range, was conducted in vegetable fields at three altitudes in Kenya from November 2011 to November 2012. Three main species were identified: Liriomyza huidobrensis (Blanchard), Liriomyza sativae Blanchard, and Liriomyza trifolii (Burgess), of which L. huidobrensis was the most abundant across all altitudes irrespective of the cropping season and accounting for over 90% of the total Liriomyza specimens collected. Liriomyza species were collected from all infested incubated leaves of 20 crops surveyed belonging to seven families: Fabaceae, Solanaceae, Cucurbitaceae, Malvaceae, Brassicaceae, Amaranthaceae, and Amaryllidaceae. However, more than 87.5% of the Liriomyza species were obtained from only four of these crops: Pisum sativum L., Phaseolus vulgaris L., Solanum lycopersicum L., and Solanum tuberosum, thereby demonstrating that Fabaceae and Solonaceae crops are the most important hosts with regard to Liriomyza species richness and relative abundance. L. huidobrensis had the widest host range (20 crops), followed by L. sativae (18 crops) and L. trifolii (12 crops). Although L. trifolii has been considered the dominant Liriomyza leafminer in Kenya, this study suggests that this may not be the case anymore, as L. huidobrensis dominates at all altitudes.
Solis, M Alma; Davis, Donald R; Nishida, Kenji
Albusambia elaphoglossumae Solis & Davis, a new genus and species, is described. It was discovered mining the fronds of the fern Elaphoglossum conspersum in Costa Rica (San José and Cartago Provinces, at elevations of 2300-3100 m). The type series was obtained by rearing of the immature stages in laboratory. The adult is defined by unique genital characters, and the pupa with a medial depression on the vertex and with two anterolateral horn-like structures on the prothorax. The larva is a gregarious leaf miner with its body flattened dorsoventrally and head prognathous; morphological adaptations to its leaf-mining habit are new to the Musotiminae. Fern-feeding musotimines are important to the discovery of new biological control agents for invasive ferns.
Scheffer, Sonja J; Hawthorne, David J
Host races play a central part in understanding the role of host plant mediated divergence and speciation of phytophagous insects. Of greatest interest are host-associated populations that have recently diverged; however, finding genetic evidence for very recent divergences is difficult because initially only a few loci are expected to evolve diagnostic differences. The holly leafminer Phytomyza glabricola feeds on two hollies, Ilex glabra and I. coriacea, that are broadly sympatric throughout most of their ranges. The leafminer is often present on both host plants and exhibits a dramatic life history difference on the two hosts, suggesting that host races may be present. We collected 1393 bp of mitochondrial cytochrome oxidase I (COI) sequence and amplified fragment length polymorphism (AFLP) data (45 polymorphic bands) from sympatric populations of flies reared from the two hosts. Phylogenetic and frequency analysis of mitochondrial COI sequence data uncovered considerable variation but no structuring by the host plant, and only limited differentiation among geographical locations. In contrast, analysis of AFLP frequency data found a significant effect with host plant, and a much smaller effect with geographical location. Likewise, neighbour-joining analysis of AFLP data resulted in clustering by host plant. The AFLP data indicate that P. glabricola is most likely comprised of two host races. Because there were no fixed differences in mitochondrial or AFLP data, this host-associated divergence is likely to have occurred very recently. P. glabricola therefore provides a new sympatric system for exploring the role of geography and ecological specialization in the speciation of phytophagous insects.
van Nieukerken, Erik J; Wagner, David L; Baldessari, Mario; Mazzon, Luca; Angeli, Gino; Girolami, Vicenzo; Duso, Carlo; Doorenweerd, Camiel
A grapevine leafminer Antispila oinophylla van Nieukerken & Wagner, sp. n., is described both from eastern North America (type locality: Georgia) and as a new important invader in North Italian vineyards (Trentino and Veneto Region) since 2006. The species is closely related to, and previously confused with Antispila ampelopsifoliella Chambers, 1874, a species feeding on Virginia creeper Parthenocissus quinquefolia (L.) Planchon., and both are placed in an informal Antispila ampelopsifoliella group. Wing pattern, genitalia, and DNA barcode data all confirm the conspecificity of native North American populations and Italian populations. COI barcodes differ by only 0-1.23%, indicating that the Italian populations are recently established from eastern North America. The new species feeds on various wild Vitis species in North America, on cultivated Vitis vinifera L. in Italy, and also on Parthenocissus quinquefolia in Italy. North American Antispila feeding on Parthenocissus include at least two other species, one of which is Antispila ampelopsifoliella. Morphology and biology of the new species are contrasted with those of North American Antispila Hübner, 1825 species and European Holocacista rivillei (Stainton, 1855). The source population of the introduction is unknown, but cases with larvae or pupae, attached to imported plants, are a likely possibility. DNA barcodes of the three European grapevine leafminers and those of all examined Heliozelidae are highly diagnostic. North American Vitaceae-feeding Antispila form two species complexes and include several as yet unnamed taxa. The identity of three out of the four previously described North American Vitaceae-feeding species cannot be unequivocally determined without further revision, but these are held to be different from Antispila oinophylla. In Italy the biology of Antispila oinophylla was studied in a vineyard in the Trento Province (Trentino-Alto Adige Region) in 2008 and 2009. Mature larvae overwinter
van Nieukerken, Erik J.; Wagner, David L.; Baldessari, Mario; Mazzon, Luca; Angeli, Gino; Girolami, Vicenzo; Duso, Carlo; Doorenweerd, Camiel
Abstract A grapevine leafminer Antispila oinophylla van Nieukerken & Wagner, sp. n., is described both from eastern North America (type locality: Georgia) and as a new important invader in North Italian vineyards (Trentino and Veneto Region) since 2006. The species is closely related to, and previously confused with Antispila ampelopsifoliella Chambers, 1874, a species feeding on Virginia creeper Parthenocissus quinquefolia (L.) Planchon., and both are placed in an informal Antispila ampelopsifoliella group. Wing pattern, genitalia, and DNA barcode data all confirm the conspecificity of native North American populations and Italian populations. COI barcodes differ by only 0–1.23%, indicating that the Italian populations are recently established from eastern North America. The new species feeds on various wild Vitis species in North America, on cultivated Vitis vinifera L. in Italy, and also on Parthenocissus quinquefolia in Italy. North American Antispila feeding on Parthenocissus include at least two other species, one of which is Antispila ampelopsifoliella. Morphology and biology of the new species are contrasted with those of North American Antispila Hübner, 1825 species and European Holocacista rivillei (Stainton, 1855). The source population of the introduction is unknown, but cases with larvae or pupae, attached to imported plants, are a likely possibility. DNA barcodes of the three European grapevine leafminers and those of all examined Heliozelidae are highly diagnostic. North American Vitaceae-feeding Antispila form two species complexes and include several as yet unnamed taxa. The identity of three out of the four previously described North American Vitaceae-feeding species cannot be unequivocally determined without further revision, but these are held to be different from Antispila oinophylla. In Italy the biology of Antispila oinophylla was studied in a vineyard in the Trento Province (Trentino-Alto Adige Region) in 2008 and 2009. Mature larvae
Ishida, Takahide A; Hattori, Kouhei; Sato, Hiroaki; Kimura, Masahito T
Quercus crispula and Q. dentata (Fagaceae) are dominant members of cool-temperate forests of Japan and are assumed to hybridize in nature. To characterize and discriminate these two species and their hybrids, we carried out multivariate analysis using several morphological traits and principal coordinate analysis using molecular (amplified fragment length polymorphism [AFLP]) data. Further, we examined the composition of Phyllonorycter species (leafmining insects) on individuals from a mixed forest. Morphological traits and Phyllonorycter composition differ enough in these two oak species to be useful for identification of species and hybrids. AFLP data, however, are less informative because the degree of molecular differentiation between the two species is low. Nine out of 105 individuals from a mixed stand had intermediate morphologies according to the multivariate analysis, and eight out of the nine individuals had intermediate Phyllonorycter composition in either one or both of the two study years. These eight individuals were tentatively assigned as hybrids or backcross individuals, and the remaining individual with intermediate morphologies was assigned as Q. dentata according to its Phyllonorycter composition and the AFLP analysis.
Hernández-López, Antonio; Rougerie, Rodolphe; Augustin, Sylvie; Lees, David C; Tomov, Rumen; Kenis, Marc; Çota, Ejup; Kullaj, Endrit; Hansson, Christer; Grabenweger, Giselher; Roques, Alain; López-Vaamonde, Carlos
Classical biological control is often advocated as a tool for managing invasive species. However, accurate evaluations of parasitoid species complexes and assessment of host specificity are impeded by the lack of morphological variation. Here, we study the possibility of host races/species within the eulophid wasp Pediobius saulius, a pupal generalist parasitoid that parasitize the highly invasive horse-chestnut leaf-mining moth Cameraria ohridella. We analysed the population genetic structure, host associations and phylogeographic patterns of P. saulius in Europe using the COI mitochondrial gene. This marker strongly supports a division into at least five highly differentiated parasitoid complexes, within two of which clades with differing degrees of host specialization were found: a Balkan clade that mainly (but not only) attacks C. ohridella and a more generalist European group that attacks many hosts, including C. ohridella. The divergence in COI (up to 7.6%) suggests the existence of cryptic species, although this is neither confirmed by nuclear divergence nor morphology. We do not find evidence of host tracking. The higher parasitism rates observed in the Balkans and the scarcity of the Balkan–Cameraria haplotypes out of the Balkans open the possibility of using these Balkan haplotypes as biological control agents of C. ohridella elsewhere in Europe. PMID:25568046
Effects of endophyte colonization of Vicia faba (Fabaceae) plants on the life-history of leafminer parasitoids Phaedrotoma scabriventris (hymenoptera: braconidae) and Diglyphus isaea (hymenoptera: eulophidae).
Akutse, Komivi S; Fiaboe, Komi K M; Van den Berg, Johnnie; Ekesi, Sunday; Maniania, Nguya K
Effects of the fungal endophytes Beauveria bassiana (isolates ICIPE 279, G1LU3, S4SU1) and Hypocrea lixii (isolate F3ST1) on the life-history of Phaedrotoma scabriventris and Diglyphus isaea, parasitoids of the pea leafminer Liriomyza huidobrensis, were studied in the laboratory. Parasitoids were allowed to parasitize 2(nd) and 3(rd) instar L. huidobrensis larvae reared on endophytically-inoculated faba bean, Vicia faba. In the control, parasitoids were reared on non-inoculated host plants. Parasitism, pupation, adult emergence and survival were recorded. No significant difference was observed between the control and the endophyte-inoculated plants in terms of parasitism rates of P. scabriventris (p = 0.68) and D. isaea (p = 0.45) and adult' survival times (p = 0.06). The survival period of the F1 progeny of P. scabriventris was reduced (p<0.0001) in B. bassiana S4SU1 to 28 days as compared to more than 40 days for B. bassiana G1LU3, ICIPE 279 and H. lixii F3ST1. However, no significant difference (p = 0.54) was observed in the survival times of the F1 progeny of D. isaea. This study has demonstrated that together, endophytes and parasitoids have beneficial effects in L. huidobrensis population suppression.
Effects of Endophyte Colonization of Vicia faba (Fabaceae) Plants on the Life–History of Leafminer Parasitoids Phaedrotoma scabriventris (Hymenoptera: Braconidae) and Diglyphus isaea (Hymenoptera: Eulophidae)
Akutse, Komivi S.; Fiaboe, Komi K. M.; Van den Berg, Johnnie; Ekesi, Sunday; Maniania, Nguya K.
Effects of the fungal endophytes Beauveria bassiana (isolates ICIPE 279, G1LU3, S4SU1) and Hypocrea lixii (isolate F3ST1) on the life-history of Phaedrotoma scabriventris and Diglyphus isaea, parasitoids of the pea leafminer Liriomyza huidobrensis, were studied in the laboratory. Parasitoids were allowed to parasitize 2nd and 3rd instar L. huidobrensis larvae reared on endophytically-inoculated faba bean, Vicia faba. In the control, parasitoids were reared on non-inoculated host plants. Parasitism, pupation, adult emergence and survival were recorded. No significant difference was observed between the control and the endophyte-inoculated plants in terms of parasitism rates of P. scabriventris (p = 0.68) and D. isaea (p = 0.45) and adult' survival times (p = 0.06). The survival period of the F1 progeny of P. scabriventris was reduced (p<0.0001) in B. bassiana S4SU1 to 28 days as compared to more than 40 days for B. bassiana G1LU3, ICIPE 279 and H. lixii F3ST1. However, no significant difference (p = 0.54) was observed in the survival times of the F1 progeny of D. isaea. This study has demonstrated that together, endophytes and parasitoids have beneficial effects in L. huidobrensis population suppression. PMID:25338084
Donovan, Michael P; Wilf, Peter; Labandeira, Conrad C; Johnson, Kirk R; Peppe, Daniel J
Plant and associated insect-damage diversity in the western U.S.A. decreased significantly at the Cretaceous-Paleogene (K-Pg) boundary and remained low until the late Paleocene. However, the Mexican Hat locality (ca. 65 Ma) in southeastern Montana, with a typical, low-diversity flora, uniquely exhibits high damage diversity on nearly all its host plants, when compared to all known local and regional early Paleocene sites. The same plant species show minimal damage elsewhere during the early Paleocene. We asked whether the high insect damage diversity at Mexican Hat was more likely related to the survival of Cretaceous insects from refugia or to an influx of novel Paleocene taxa. We compared damage on 1073 leaf fossils from Mexican Hat to over 9000 terminal Cretaceous leaf fossils from the Hell Creek Formation of nearby southwestern North Dakota and to over 9000 Paleocene leaf fossils from the Fort Union Formation in North Dakota, Montana, and Wyoming. We described the entire insect-feeding ichnofauna at Mexican Hat and focused our analysis on leaf mines because they are typically host-specialized and preserve a number of diagnostic morphological characters. Nine mine damage types attributable to three of the four orders of leaf-mining insects are found at Mexican Hat, six of them so far unique to the site. We found no evidence linking any of the diverse Hell Creek mines with those found at Mexican Hat, nor for the survival of any Cretaceous leaf miners over the K-Pg boundary regionally, even on well-sampled, surviving plant families. Overall, our results strongly relate the high damage diversity on the depauperate Mexican Hat flora to an influx of novel insect herbivores during the early Paleocene, possibly caused by a transient warming event and range expansion, and indicate drastic extinction rather than survivorship of Cretaceous insect taxa from refugia.
Pocock, Michael J O; Evans, Darren M
Citizen science is an increasingly popular way of undertaking research and simultaneously engaging people with science. However, most emphasis of citizen science in environmental science is on long-term monitoring. Here, we demonstrate the opportunities provided by short-term hypothesis-led citizen science. In 2010, we ran the 'Conker Tree Science' project, in which over 3500 people in Great Britain provided data at a national scale of an insect (horse-chestnut leaf-mining moth, Cameraria ohridella) undergoing rapid range-expansion. We addressed two hypotheses, and found that (1) the levels of damage caused to leaves of the horse-chestnut tree, Aesculus hippocastanum, and (2) the level of attack by parasitoids of C. ohridella larvae were both greatest where C. ohridella had been present the longest. Specifically there was a rapid rise in leaf damage during the first three years that C. ohridella was present and only a slight rise thereafter, while estimated rates of parasitism (an index of true rates of parasitism) increased from 1.6 to 5.9% when the time C. ohridella had been present in a location increased from 3 to 6 years. We suggest that this increase is due to recruitment of native generalist parasitoids, rather than the adaptation or host-tracking of more specialized parasitoids, as appears to have occurred elsewhere in Europe. Most data collected by participants were accurate, but the counts of parasitoids from participants showed lower concordance with the counts from experts. We statistically modeled this bias and propagated this through our analyses. Bias-corrected estimates of parasitism were lower than those from the raw data, but the trends were similar in magnitude and significance. With appropriate checks for data quality, and statistically correcting for biases where necessary, hypothesis-led citizen science is a potentially powerful tool for carrying out scientific research across large spatial scales while simultaneously engaging many people with
Donovan, Michael P.; Wilf, Peter; Labandeira, Conrad C.; Johnson, Kirk R.; Peppe, Daniel J.
Plant and associated insect-damage diversity in the western U.S.A. decreased significantly at the Cretaceous-Paleogene (K-Pg) boundary and remained low until the late Paleocene. However, the Mexican Hat locality (ca. 65 Ma) in southeastern Montana, with a typical, low-diversity flora, uniquely exhibits high damage diversity on nearly all its host plants, when compared to all known local and regional early Paleocene sites. The same plant species show minimal damage elsewhere during the early Paleocene. We asked whether the high insect damage diversity at Mexican Hat was more likely related to the survival of Cretaceous insects from refugia or to an influx of novel Paleocene taxa. We compared damage on 1073 leaf fossils from Mexican Hat to over 9000 terminal Cretaceous leaf fossils from the Hell Creek Formation of nearby southwestern North Dakota and to over 9000 Paleocene leaf fossils from the Fort Union Formation in North Dakota, Montana, and Wyoming. We described the entire insect-feeding ichnofauna at Mexican Hat and focused our analysis on leaf mines because they are typically host-specialized and preserve a number of diagnostic morphological characters. Nine mine damage types attributable to three of the four orders of leaf-mining insects are found at Mexican Hat, six of them so far unique to the site. We found no evidence linking any of the diverse Hell Creek mines with those found at Mexican Hat, nor for the survival of any Cretaceous leaf miners over the K-Pg boundary regionally, even on well-sampled, surviving plant families. Overall, our results strongly relate the high damage diversity on the depauperate Mexican Hat flora to an influx of novel insect herbivores during the early Paleocene, possibly caused by a transient warming event and range expansion, and indicate drastic extinction rather than survivorship of Cretaceous insect taxa from refugia. PMID:25058404
Al-Zyoud, Firas Ahmad
Due to the importance of wheat and barley production in Jordan, prevention of the cereal leafminer, Syringopais temperatella Led. (Lepidoptera: Scythrididae) is of vital importance. The insect is a severe pest and plays an important role in limiting the production of these crops. The use of insecticides is neither economic nor sustainable, so that there is an urgent need to initiate a viable alternative to chemical control. Therefore, this study aimed at investigating the effect of crop rotation on S. temperatella and its preference to different wheat and barley cultivars. The field history experiment was conducted using five different crop rotations. For the preference experiments in the laboratory, two major experimental groups were conducted. The first was set up to measure the consumed leaf area and the second one to record the number of larval attaches. Each group consisted of four different subgroups; 6 wheat cultivars, 6 barley cultivars, two and one cultivar of each crop. The results indicated that the infestation percentage and number of larvae were significantly the lowest in the crop rotation, wheat/chickpea/wheat while the highest were recorded for barley/barley/barley. The preference results showed that wheat cultivar, Horani Nawawi is significantly the most preferred while Horani 27 is the least cultivar. In case of barley, Mutah was the most preferred cultivar and the least preference was recorded for Athroh. Also, wheat was significantly less preferred than barley. The wheat cultivars, Sham, Em-Qees and Acsad 65 had the highest number of attaches and Deer Alla the least. In contrast, the barley cultivar, Acsad 176 had the highest and Athroh and Rum 1 had the least attaches. Barley cultivars had higher attaches than wheat ones. There was a positive relation between the infestation percent and number of larvae, as well as the consumed area and number of attaches in all of the four subgroups. In conclusion, the crop rotation, wheat
Pathogenicity of entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana (Hypocreales: Clavicipitaceae) isolates to the adult pea leafminer (Diptera: Agromyzidae) and prospects of an autoinoculation device for infection in the field.
Migiro, L N; Maniania, N K; Chabi-Olaye, A; Vandenberg, J
Seventeen isolates of Metarhizium anisopliae (Metschnikoff) Sorokin and three isolates of Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Clavicipitaceae) were evaluated for their pathogenicity to the adult pea leafminer, Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae), in the laboratory. Flies were contaminated with dry conidia through a velvet material wrapped around the inner side of a cylindrical plastic tube. All the isolates were pathogenic to the pea leafminer, causing mortality between 40 and 100% at 5 d after exposure. The lethal time for 50% mortality (LT(50)) ranged from 2.6 to 5.4 d, whereas the LT(90) values varied between 3.2 and 9.1 d depending on the isolate. An autoinoculation device was evaluated in cage field experiments using only one of the virulent isolates, M. anisopliae ICIPE 20. The device was loaded with 2-3 g of dry conidia. Mortality of up to 100% was observed in flies captured from fungus-treated cages held under laboratory conditions. The average number of spores picked up by a single fly visiting the device increased with days after inoculation. One day after the inoculation, adults picked up an average of 4.1 +/- 0.7 x 10(5) conidia and 39.6 +/- 4.0 x 10(5) conidia 5 d after inoculation. Depending on the sampling date, the LT(50) varied between 1.8 and 3.4 d. Results indicate that some isolates of B. bassiana and M. anisopliae are highly pathogenic to L. huidobrensis, suggesting a potential for their use in the control of this pest. They also suggest the possibility of L. huidobrensis suppression with fungi using an autoinoculation device.
Raimondo, Fabio; Trifilò, Patrizia; Gullo, Maria A Lo
Gas exchange and hydraulic features were measured in leaves of three different Citrus species (Citrus aurantium L., Citrus limon L., Citrus × paradisii Macfad) infested by Phyllocnistis citrella Staiton, with the aim to quantify the impact of this pest on leaf hydraulics and, ultimately, on plant fitness. Infested leaves were characterized by the presence on the leaf blade of typical snake-shaped mines and, in some cases, of a crumpled leaf blade. Light microscopy showed that leaf crumpling was induced by damage to the cuticular layer. In all three Citrus species examined: (a) the degree of infestation did not exceed 10% of the total surface area of infested plants; (b) control and infested leaves showed similar values of minimum diurnal leaf water potential, leaf hydraulic conductance and functional vein density; and (c) maximum diurnal values of stomatal conductance to water vapour, transpiration rate and photosynthetic rate (An) were similar in both control leaves and the green areas of infested leaves. A strong reduction of An was recorded only in mined leaf areas. Our data suggest that infestation with P. citrella does not cause conspicuous plant productivity reductions in young Citrus plants, at least not in the three Citrus species studied here.
Hoy, M.A.; Jeyaprakash, A.; Clarke-Harris, D.
These data indicate that the population of A. citricola in Jamaica probably originated from the Australian (Thailand), rather than from the Taiwan, population. This is consistent with what is currently known about the origin of the established Ageniaspis population in Florida (Alvarez 2000). It is not known when, or how, A. citricola arrived in Jamaica, although the CLM was detected there in 1994. The fortuitous establishment of A. citricolaon the CLM in Jamaica is not the only such establishment of a natural enemy discovered during this 2004 survey of citrus. The parasitoid Lipolexis oregmae Gahan (Hymenoptera: Aphidiidae) was found attacking the brown citrus aphid, Toxoptera citricida Kirkaldy (Hemiptera: Aphididae) (Hoy et al., unpublished data), and the eulophid parasitoid Tamarixia radiata Waterston was found attacking the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). The fact that 3 natural enemies of 3 invasive citrus pests were found in Jamaica, none of which were purposefully imported and released, suggests that pest-infested citrus trees were imported into Jamaica without going through appropriate quarantine procedures. Because each pest arrived at different times, the parasitoids probably arrived at different times, as well. This indicates that an analysis is needed to identify the critical control points within those services in Jamaica that support border protection, and that procedures may require strengthening. (author)
Carriére, Y; Millar, J G; McNeil, J N; Miller, D; Underbill, E W
Gas chroinatography of hexane extracts of 3-day-old virgin A.frontella adults revealed a branched saturated hydrocarbon present only in females. This compound was isolated by argentation chromotography and preparative GC, identified by GC and GC-MS as 3,7-dimethylnonadecane, and subsequently synthesized. Three-day-old virgin females contained 54.1 ± 3.5 ng (± SEM;N = 48) of 3,7-dimethylnonadecane. Male cadavers do not elicit male courtship behavior, but when treated with ∼ 18 ng of 3,7-dimethylnonadecane they were as attractive as cadavers of 3-day-old virgin females. Black cotton knots were less attractive than male cadavers when treated with 3,7-dimethylnonadecane, but all bioassays indicated that this compound is an important semiochemical modulating male mating behavior.
Luksiene, Zivile; Kurilcik, Natalija; Jursenas, Saulius; Radziute, Sandra; Būda, Vincas
Development of new, ecologically safe technologies to control insect pest populations is of great importance. Photoactive compounds usually used for photosensitization might be effective as pesticide agents, with low impact on the environment, being non-toxic and not mutagenic. Phosensitizer accumulates within the insect body and, following exposure to visible light, induces lethal photochemical reactions and death. The aim of this study is to evaluate the possible usage of several photosensitizers (acridine orange, aminolevulinic acid, hematoporphyrin dimethyl ether, methylene blue) as photopesticides to control population of polyphagous plant pest Liriomyza bryoniae (Kaltenbach, 1858) (Diptera, Agromyzidae). Fluorescence measurements of intact cooled insects indicate that insect feeding with bait containing HPde and sugar induces remarkable accumulation of this compound in the body of insect. This accumulation is strongly dependent on sex and feeding duration. The highest HPde amount in the body of insect was detected 16 h after feeding, whereas no significant photosensitizer amount was detected in the same insect following 48 h. Following irradiation with visible light results in fast death of L. bryoniae. Of importance to note that survival of insects after feeding and irradiation depends on sex: female insect died much faster than males.
Brown, Valerie K.
Discusses the use of leaf mines (formed by larvae of small moths or flies) and galls (wasps' larvae) in various insect population studies. Also considers the advantages of using these structures for instructional purposes. (DH)
Abstract A checklist of the Agromyzidae (Diptera) recorded from Finland is presented. 279 (or 280) species are currently known from the country. Phytomyza linguae Lundqvist, 1947 is recorded as new to Finland. PMID:25337025
Successful development and commercial launch of the first semiochemical-based control method for a major exotic insect pest and associated disease of citrus in Florida have resulted from vigorous collaboration between university and government researchers with support from private industry and innov...
Calvo, F J; Soriano, J D; Stansly, P A; Belda, J E
Necremnus tutae is native to the Mediterranean region where it has been observed in greenhouses parasitizing the invasive Tuta absoluta on tomato. The objective of the present study was to determine whether augmentative releases of N. tutae can improve existing biological control of T. absoluta based on predation by Nesidicoris tenuis. Two experiments were carried out, of which the first evaluated different N. tutae release rates (1 and 2 N. tutae m-2 week-1). The parasitoid reduced plant and fruit damage, especially at the higher rate. However, such reduction was considered insufficient given the large numbers of parasitoids needed and still unacceptable level of fruit damage. The second experiment focused on combining the most efficient rate of N. tutae of those evaluated during the first experiment, with the pre- and post-planting release of N. tenuis and supplemental additions of Ephestia kuehniella eggs. Addition of N. tutae decreased leaf damage by T. absoluta regardless the release method for N. tenuis, but the pre-plant release of N. tenuis alone was sufficient to prevent fruit damage by T. absoluta. This suggested that the addition of N. tutae may not be necessary to obtain satisfactory control of T. absoluta following pre-plant application of N. tenuis, although different options for using N. tutae in commercial crops may still be possible.
... country for the weevil Faustinus ovatipennis, pea leafminer, tomato fruit borer, banana moth, lantana... Faustinus ovatipennis, pea leafminer, tomato fruit borer, banana moth, lantana mealybug, passionvine... borer, banana moth, lantana mealybug, passionvine mealybug, melon thrips, the rust fungus...
..., Epinotia aporema, Maruca testulalis, and leafminers MB T101-k-2. Okra (pod) Pectinophora gossypiella MB... fabivora, Epinotia aporema, Maruca testulalis, and leafminers MB T101-k-2. Okra (pod) Pectinophora..., Maruca testulalis, and leafminers MB T101-k-2. Okra (pod) Pectinophora gossypiella MB T101-p-2....
Huemer, Peter; Lopez-Vaamonde, Carlos; Triberti, Paolo
Abstract The Alps are a hotspot of biodiversity in Europe with many Lepidoptera species still to be discovered. Here we describe a new gracillariid genus and species, Mercantouria neli gen. n. and sp. n. The morphology of the male genitalia is highly differentiated with unique features. DNA barcodes show that its nearest neighbor is the North American species ‘Caloptilia’ scutellariella (Braun, 1923). Mercantouria neli is known from four adults (two males and two females) collected at two localities in the French Alps. Its host plant and life cycle remain unknown. PMID:27199612
Brito, Rosângela; Gonçalves, Gislene L.; Vargas, Hector A.; Moreira, Gilson R. P.
Abstract Male, female, pupa, larva and egg of a new genus and species of Gracillariidae (Gracillariinae), Spinivalva gaucha Moreira and Vargas from southern Brazil are described and illustrated with the aid of optical and scanning electron microscopy. A preliminary analysis of mitochondrial DNA sequences including members of related lineages is also provided. The immature stages are associated with Passiflora actinia, Passiflora misera and Passiflora suberosa (Passifloraceae), and build mines on the adaxial leaf surface. Initially the mines are serpentine in shape, but later in larval ontogeny become a blotch type. Although the larvae are hypermetamorphic as in other Gracillariidae, there is no sap-feeding instar in Spinivalva gaucha; the larva feeds on the palisade parenchyma, thus producing granular frass during all instars. Pupation occurs outside the mine; prior to pupating, the larva excretes numerous bubbles that are placed in rows on the lateral margins of the cocoon external surface. This is the second genus of gracillariid moth described for the Atlantic Rain Forest, and the second gracillariid species known to be associated with Passifloraceae. PMID:23794860
Recent surveys in southern Florida, USA, Brazil and Argentina, for biological control agents to assist in the control of the invasive Brazilian peppertree, have discovered several previously unknown species of plant mining Lepidoptera of the family Gracillariidae. Morphological descriptions with sum...
Leurocephala schinusae Davis & Mc Kay (Lepidoptera: Gracillariidae) was studied to assess its suitability as a biological control agent of Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae), a serious environmental weed in the USA and elsewhere in the world. The host range was determined by ...
Hoare, Robert J.B.; van Nieukerken, Erik J.
Abstract The phylogeny of the mainly Australian nepticulid genus Pectinivalva Scoble, 1983 is investigated on the basis of morphology, and a division into three monophyletic subgenera is proposed on the basis of these results. These subgenera (Pectinivalva, Casanovula Hoare, subgen. n. and Menurella Hoare, subgen. n. ) are described and diagnosed, the described species of Pectinivalva are assigned to them, and representative new species are described in each: Pectinivalva (Pectinivalva) mystaconota Hoare, sp. n., Pectinivalva (Casanovula) brevipalpa Hoare, sp. n., Pectinivalva (Casanovula) minotaurus Hoare, sp. n., Pectinivalva (Menurella) scotodes Hoare, sp. n., Pectinivalva (Menurella) acmenae Hoare, sp. n., Pectinivalva (Menurella) xenadelpha Van Nieukerken & Hoare, sp. n., Pectinivalva (Menurella) quintiniae Hoare & Van Nieukerken, sp. n., and Pectinivalva (Menurella) tribulatrix Van Nieukerken & Hoare, sp. n. Pectinivalva (Menurella) quintiniae (from Quintinia verdonii, Paracryphiaceae) is the first known member of the genus with a host-plant not belonging to Myrtaceae. Pectinivalva (Menurella) xenadelpha from Mt Gunung Lumut, Kalimantan, Borneo, is the first pectinivalvine reported from outside Australia. Keys to the subgenera of Nepticulidae known from Australia, based on adults, male and female genitalia, and larvae, are presented. Host-plant relationships of Pectinivalva are discussed with relation to the phylogeny, and a list of known host-plants of Pectinivalva, including hosts of undescribed species, is presented. DNA barcodes are provided for most of the new and several unnamed species. PMID:23794827
Abraham, Cheri M; Braman, S K; Oetting, R D; Hinkle, N C
Pesticides commonly used in commercial greenhouse management were evaluated for compatibility with two biological control agents: a leafminer parasitoid (Diglyphus isaea [Walker]), and a predatory mite (Neoseiulus californicus [McGregor]). These natural enemies were exposed to miticides, fungicides, and insecticides targeting leafminers, thrips, and whiteflies, according to label directions in laboratory vial assays, after which mortality at 12, 24, and 48 h was recorded. Greater mortality of predatory mites than leafminer parasitoids was observed overall, illustrating that fewer pesticides were compatible with predatory mites compared with the parasitoid. However, some commonly used pesticides were found to cause high mortality to both the leafminer parasitoid and predatory mites. Twospotted spider mite (Tetranychus urticae Koch) infestations often disrupt leafminer (Liriomyza trifolii [Burgess]) biocontrol programs. Therefore, potentially compatible miticides (bifenazate, hexythiazox, spiromesifen, acequinocyl, etoxazole, and clofentezine) identified in laboratory trials were also evaluated in a greenhouse study and found to be compatible with leafminer biocontrol.
Carvalho, A R; Bueno, V H P; Silva, D B; Costa, V A
Leafminers (Diptera: Agromyzidae) are pests of various crops, mainly in greenhouses, and have Diglyphus spp. as important leafminer larval parasitoids. Until recently, only Diglyphus insularis (Gahan) had been reported in Brazil. In here we report the first records of Diglyphus begini (Ashmead), D. intermedius (Girault) and D. isaea (Walker) in Brazil. These parasitoids were found parasitizing leafminer larvae on cultivated and spontaneous plants in some areas of Minas Gerais state, Brazil.
New neotropical species of Opiinae (Hymenoptera, Braconidae) reared from fruit-infesting and leaf-mining Tephritidae (Diptera) with comments on the Diachasmimorpha mexicana species group and the genera Lorenzopius and Tubiformopius
Wharton, Robert; Ward, Lauren; Miko, Istvan
Abstract Four new species of opiine Braconidae are described from Mexico. These are Diachasmimorpha martinalujai Wharton reared from Rhagoletis infesting fruits of Crataegus spp., Diachasmimorpha norrbomi Wharton reared from Euphranta mexicana infesting fruits of Ribes pringlei, Eurytenes (Stigmatopoea) norrbomi Wharton reared from Trypeta concolor mining leaves of Barkleyanthus salicifolia and Eurytenes (Stigmatopoea) maya Wharton reared from Rhagoletis pomonella infesting apples and fruits of Crataegus spp. Morphological features of the first metasomal segment and occipital carina, useful for placement of these species, are discussed relative to the genera Diachasmimorpha, Eurytenes, Lorenzopius, Tubiformopius, and Opius s.l. Descriptions and diagnoses are referenced to the Hymenoptera Anatomy Ontology. The following represent new combinations: Diachasmimorpha hildagensis, Lorenzopius euryteniformis, and Tubiformopius tubibasis. Revised diagnoses are provided for Diachasmimorpha hildagensis, Diachasmimorpha mexicana, Diachasmimorpha sanguinea, Eurytenes (Stigmatopoea), Lorenzopius, Lorenzopius euryteniformis, Tubiformopius, Tubiformopius tubigaster, Tubiformopius tubibasis, Opius incoligma, and Opius rugicoxis. Two species groups are delineated within Lorenzopius and a key to species of Diachasmimorpha occurring in the New World is provided. PMID:23818811
Agromyzid leafminers are economic and quarantine pests of a variety of vegetables, flowers and ornamental foliage. Methyl bromide fumigation is often used as a phytosanitary treatment when quarantined agromyzids are found in shipped commodities; alternative treatments are sought. Ionizing radiation...
Remeikis, Andrius; Stonis, Jonas R
We describe three new species: Stigmella crassifoliae Remeikis & Stonis, sp. nov. (a leaf-miner on Quercus crassifolia and Q. crispipilis from the highlands of Guatemala), S. robleae Remeikis & Stonis, sp. nov., and S. humboldti Remeikis & Stonis, sp. nov. (leaf-miners on Quercus humboldtii from the Colombian Andes). No Quercus-feeding Nepticulidae species were previously known from South America. All new species are illustrated with photographs of the leaf-mines, cocoons, adults, and genitalia. In the S. saginella species group, for the species possessing in male genitalia M-shaped gnathos with caudal processes closely juxtaposed and phallus without cornuti, a new species complex (the S. nigriverticella complex) is defined. We also provide a pictorial key to the species of the new complex.
Vogler, Ute; Rott, Anja S; Gessler, Cesare; Dorn, Silvia
Terpene-mediated interactions between transgenic or classically bred apple genotypes and associated insects were investigated. Apple genotypes were either resistant or susceptible to Venturia inaequalis that causes apple scab. They were subjected to infestation by Phyllonorycter leafminers and/or inoculation with V. inaequalis. Apple leaf extracts were analyzed by gas chromatography-mass spectrometry to quantify squalene, a triterpene known to mediate host location by Pholetesor parasitoids that are specialized on leafminers. Squalene contents in leafminer-infested leaves differed between the transgenic apple scab resistant line and a classically bred cultivar sharing the same resistance gene. This resistant cultivar showed an increase in squalene contents from healthy to leafminer-infested leaves. This was not the case in the transgenic resistant line. However, there was also no increase in the susceptible isogenic cultivar. Behavioral bioassays with parasitoid females also reflected these findings. Hence, alterations in leaf chemistry and corresponding responses of the parasitoid are apparent among classically bred cultivars, rather than in the genetically modified resistant line.
Our study investigated the patterns of attack by hymenopteran parasitoids in the Tupelo leafminer, Antispila nysaefoliella Clemens, to understand the selective pressures that shape host group size and timing of emergence. A large sample of host larvae was collected from a natural field population of...
Fruit losses due to citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), vary each crop season depending on citrus variety, tree age, flushing condition, leafminer control, and coincidence of weather events with occurrence of susceptible fruit and foliage. In 2013, crop losses in Hamlin f...
Fruit losses due to citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), vary each crop season depending on citrus variety, tree age, flushing condition, leafminer control, and coincidence of weather events with occurrence of susceptible fruit and foliage. In 2012, crop losses in Hamlin f...
A new species of leafmining fly in the genus Phytomyza Fallén (Diptera: Agromyzidae) is described from Gelsemium Juss, representing the first known instance of an agromyzid feeding on Gelsemiaceae (Asteridae). The host plant, G. sempervirens (L.) (the “evening trumpetflower”), and possibly also G. r...
Wei, Jia-Ning; Zhu, Junwei; Kang, Le
Liriomyza sativae Blanchard and Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae) are two invasive flies in China that have caused economical damage on vegetables and ornamental plants. In this article, we report the profiles of emitted volatiles from healthy, mechanically damaged, and leafminer-damaged bean, Phaseolus vulgaris L., plants. Among 25 emitted volatiles identified, (E)-2-hexen-1-al, (3E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), (Z)-3-hexenyl acetate, (Z)-3-hexen-1-ol, (syn)- and (anti)-2-methylpropanal oxime, (syn)-2-methylbutanal oxime, linalool, and (E,E)-alpha-farnesene were consistently released from damaged bean plants. Combined amounts of these nine compounds made up more than 70% of the total volatiles emitted from each treatment. No qualitative differences in volatile emission were found between bean plants damaged by the two fly species; however, amounts of several major compounds induced by L. huidobrensis damage were significantly higher than those from plants damaged by L. sativae. The mechanically damaged plants released a higher proportion of green leaf volatiles than plants in the other treatments, whereas leafminer-damaged plants produced more terpenoids and oximes. Furthermore, the volatile profiles emitted from plants, damaged by adult leafminers, by second instar larvae, and even the plants with empty mines left by leafminer larvae (the pupal stage) were significantly different. The identification of volatile oximes released from damaged plants was confirmed and is discussed in a behavioral and biological control context.
Maharjan, Rameswor; Jung, Chuleui
Liriomyza huidobrensis (Blanchard) is a serious invasive pest of potato in Korea. In sessile insect herbivores like leafminer flies, host plant choice is a critical decision made by adults for offspring survival, and one that is often influenced by host plant quality. In annual host plants like potato, leafminer choice is sometimes influenced by cultivar characteristics. To determine the basis of host selection, the odor and feeding preferences of adult L. huidobrensis were examined using a five-arm olfactometer offering a choice of five different potato cultivars: 'Chubeak', 'Seohong', 'Goun', 'Dejima', and 'Sumi'. Preferences of adult leafminers varied significantly among potato cultivars. Liriomyza huidobrensis showed a preference for the Goun cultivar in both olfactory and adult feeding tests. When measured 2 wk after release onto actual plants, plant damage ratings and the number of mines were consistent with the feeding preference results. Further studies should examine the influence of cultivar characteristics on larval fitness and adult longevity to develop a resistant potato cultivar through the selection behavior of leafminers.
Wei, Jianing; Wang, Lizhong; Zhu, Junwei; Zhang, Sufang; Nandi, Owi I.; Kang, Le
Background Plant volatiles play an important role in defending plants against insect attacks by attracting their natural enemies. For example, green leaf volatiles (GLVs) and terpenoids emitted from herbivore-damaged plants were found to be important in the host location of parasitic wasps. However, evidence of the functional roles and mechanisms of these semio-chemicals from a system of multiple plants in prey location by the parasitoid is limited. Little is known about the potential evolutionary trends between herbivore-induced host plant volatiles and the host location of their parasitoids. Methodology/Principal Findings The present study includes hierarchical cluster analyses of plant volatile profiles from seven families of host and non-host plants of pea leafminer, Liriomyza huidobrensis, and behavioral responses of a naive parasitic wasp, Opius dissitus, to some principal volatile compounds. Here we show that plants can effectively pull wasps, O. dissitus, towards them by releasing a universally induced compound, (Z)-3-hexenol, and potentially keep these plants safe from parasitic assaults by leafminer pests, L. huidobrensis. Specifically, we found that volatile profiles from healthy plants revealed a partly phylogenetic signal, while the inducible compounds of the infested-plants did not result from the fact that the induced plant volatiles dominate most of the volatile blends of the host and non-host plants of the leafminer pests. We further show that the parasitoids are capable of distinguishing the damaged host plant from the non-host plant of the leafminers. Conclusions/Significance Our results suggest that, as the most passive scenario of plant involvement, leafminers and mechanical damages evoke similar semio-chemicals. Using ubiquitous compounds, such as hexenol, for host location by general parasitoids could be an adaptation of the most conservative evolution of tritrophic interaction. Although for this, other compounds may be used to improve the
Kobayashi, Shigeki; Huang, Guo-hua; Nakamura, Akihiro; Hirowatari, Toshiya
Four new leaf mining Oecophyllembiinae (Gracillariidae) species are described from China and Japan: Metriochroa symplocosella sp. nov. (host plants: Symplocos anomala, S. sumuntia, Symplocaceae) from China, Guttigera schefflerella sp. nov. (host plant: Schefflera octophylla, Araliaceae), Eumetriochroa araliella sp. nov. (host plants: Dendropanax trifidus, Evodiopanax innovans, Eleutherococcus sciadophylloides and Fatsia japonica, Araliaceae) and Corythoxestis tricalysiella sp. nov. (host plant: Tricalysia dubia, Rubiaceae) from Japan. Corythoxestis sunosei (Kumata, 1998) is recorded from new host plants: Adinapilulifera and Mussaenda parviflora, Rubiaceae, from Japan. The female adult and pupal morphologies, life history and host plant of the genus Guttigera are described for the first time. Pupae of seven species of four genera: Corythoxestis, Eumetriochroa, Guttigera, and Metriochroa, are described for the first time. We provide morphological diagnostic differences between species and genera of Oecophyllembiinae and Phyllocnistis. Our preliminary data suggest that Oecophyllembiinae species have three valuable pupal diagnostic characters: 1) cocoon cutter with unique lateral processes or setae on the clypeus, 2) tergal spines with only a pair of dorsal setae, and 3) cremaster with more than two pairs of caudal processes, while Phyllocnistis species possess 1) cocoon cutter without lateral processes or setae on clypeus, 2) tergal spines with a pair of dorsal setae and dorsal hooks, and 3) cremaster with only a pair of caudal processes.
Meyhöfer, R.; Casas, J.; Dorn, S.
The aim of this paper was to obtain behavioral evidence of vibration mediated interactions between the apple tentiform leafminer Phyllonorycter malella (Ger.) (Lepidoptera, Gracillariidae) and its parasitoid Sympiesis sericeicornis Nees (Hymenoptera, Eulophidae). The experimental set-up allowed the simultaneous recording on video film of both the parasitoids and the hosts behavior, thus enabling us to contrast their respective responses to the leaf vibrations produced by the other party. We analysed the one step transition probabilties from one behavioral state to the following. Active larval movements had a marked influence on the parasitoid's behavior, while feeding and still had no detectable effect. We found no evidence for vibrotaxis on the part of the parasitoid. While parasitoid searching behavior on the leaf surface did not seem to alter the leafminers behavior, ovipositor insertions triggered a characteristic avoidance response. The described interactions are discussed in the context of the 'princess and monster' model developed in search and game theory.
Stonis, Jonas R; Diškus, Arūnas; Remeikis, Andrius; Remeikis, Andrius; Davis, Donald R; Solis, M Alma; Torres, Nixon Cumbicus
We record the first Nepticulidae species found to feed on Baccharis L. (Asteraceae). Despite the high species richness of Baccharis in the Western Hemisphere, no nepticulid has ever been recorded feeding on Baccharis. In this paper we describe six new Stigmella Schrank species feeding on Baccharis: S. emarginatae Diškus & Stonis, sp. nov., S. bipartita Diškus & Stonis, sp. nov., S. tripartita Diškus & Stonis, sp. nov., S. latifoliae Remeikis, Diškus & Stonis, sp. nov., S. baccharicola Diškus & Stonis, sp. nov., and S. confertae Diškus & Stonis, sp. nov. The remaining two taxa are left unnamed. All taxa are illustrated with photographs of adults, their genitalia, and their leaf-mines. Additionally, leaf-mines on Baccharis salicifolia are documented.
Nakamura, Shigeo; Masuda, Toshio; Mochizuki, Atsushi; Konishi, Kazuhiko; Tokumaru, Susumu; Ueno, Keiichiro; Yamaguchi, Takuhiro
Leafminer flies, especially, Liriomyza huidobrensis, Liriomyza sativae and Liriomyza trifolii, are quarantine species in many countries. Their morphological similarity makes identification difficult. To develop a rapid, reliable, sensitive and simple molecular identification method using multiplex PCR, we newly sequenced the mitochondrial cytochrome oxidase I (COI) genes of Liriomyza bryoniae, Liriomyza chinensis, L. huidobrensis, L. sativae, L. trifolii, Chromatomyia horticola and four parasitoid species. We aligned them with all the COI sequences of the leafminer flies found in the international DNA nucleotide sequence databases (DDBJ/EMBL/GenBank). We then designed species-specific primers to allow us to differentiate between L. bryoniae, L. chinensis, L. huidobrensis, L. sativae, and L. trifolii.
Guantai, M M; Ogol, C P K O; Salifu, D; Kasina, J M; Akutse, K S; Fiaboe, K K M
Three Liriomyza species [Liriomyza huidobrensis (Blanchard), Liriomyza trifolii (Burgess), and Liriomyza sativae Blanchard] have been reported as the most important leafminer pests in vegetable production systems in Africa. In Kenya, farmers rely on indiscriminate synthetic insecticides use. On-farm field investigations were set up at three different locations (Sagana, Kabaru, and Naromoru) in central Kenya to determine the effect of pesticide application on the abundance of leafminers and their parasitoids under three management practices, namely: farmer practice (FP), reduced pesticide use (RP), and a control with no use of pesticides (CO). In addition, laboratory experiments were designed to test the effect of commonly used pesticides in pea production systems in central Kenya--Dimethoate, Dynamec, Thunder, Cyclone, Bestox, Folicur, Milraz, and Bulldock--on L. huidobrensis and two of its parasitoids, Diglyphus isaea Walker and Phaedrotoma scabriventris Nixon. The mean numbers of leafminer flies in control treatment were higher than in RP and FP in both first and second seasons across all sites, but RP and FP did not differ significantly. Parasitoid numbers were very low and there was no much variation between treatments at each location in both first and second seasons. No significant differences were observed between the three management practices with regards to the yield measurements. In the laboratory, the estimated LD50 values for L. huidobrensis larvae were all more than two times higher than the recommended dosages, while the LD50 of adults were below the recommended dosages. The estimated LD50 values for the parasitoids were much lower than recommended dosages for all pesticides except Thunder. This study, therefore, demonstrates that the pesticides currently used do not control the Liriomyza leafminer larvae that constitute the most destructive stage of the pest, but are rather detrimental to their parasitoids. In addition, the current low level of
Prochazka, A.; Dammer, J.; Weyda, F.; Sopko, V.; Benes, J.; Zeman, J.; Jandejsek, I.
This study presents an applicability of real-time microradiography to biological objects, namely to horse chestnut leafminer, Cameraria ohridella (Insecta: Lepidoptera, Gracillariidae) and following image processing focusing on image segmentation and object recognition. The microradiography of insects (such as horse chestnut leafminer) provides a non-invasive imaging that leaves the organisms alive. The imaging requires a high spatial resolution (micrometer scale) radiographic system. Our radiographic system consists of a micro-focus X-ray tube and two types of detectors. The first is a charge integrating detector (Hamamatsu flat panel), the second is a pixel semiconductor detector (Medipix2 detector). The latter allows detection of single quantum photon of ionizing radiation. We obtained numerous horse chestnuts leafminer pupae in several microradiography images easy recognizable in automatic mode using the image processing methods. We implemented an algorithm that is able to count a number of dead and alive pupae in images. The algorithm was based on two methods: 1) noise reduction using mathematical morphology filters, 2) Canny edge detection. The accuracy of the algorithm is higher for the Medipix2 (average recall for detection of alive pupae =0.99, average recall for detection of dead pupae =0.83), than for the flat panel (average recall for detection of alive pupae =0.99, average recall for detection of dead pupae =0.77). Therefore, we conclude that Medipix2 has lower noise and better displays contours (edges) of biological objects. Our method allows automatic selection and calculation of dead and alive chestnut leafminer pupae. It leads to faster monitoring of the population of one of the world's important insect pest.
Askari-Saryazdi, Ghasem; Hejazi, Mir Jalil; Ferguson, J Scott; Rashidi, Mohammad-Reza
The vegetable leafminer (VLM), Liriomyza sativae (Diptera: Agromyzidae) is a serious pest of vegetable crops and ornamentals worldwide. In cropping systems with inappropriate management strategies, development of resistance to insecticides in leafminers is probable. Chlorpyrifos is a commonly used pesticide for controlling leafminers in Iran, but resistance to this insecticide in leafminers has not been characterized. In order to develop strategies to minimize resistance in the field and greenhouse, a laboratory selected chlorpyrifos resistant strain of L. sativae was used to characterize resistance and determine the rate of development and stability of resistance. Selecting for resistance in the laboratory after 23 generations yielded a chlorpyrifos resistant selected strain (CRSS) with a resistance ratio of 40.34, determined on the larval stage. CRSS exhibited no cross-resistance to other tested insecticides except for diazinon. Synergism and biochemical assays indicated that esterases (EST) had a key role in metabolic resistance to chlorpyrifos, but glutathione S-transferase (GST) and mixed function oxidase (MFO) were not mediators in this resistance. In CRSS acetylcholinesterase (AChE) was more active than the susceptible strain, Sharif (SH). AChE in CRSS was also less sensitive to inhibition by propoxur. The kinetics parameters (Km and Vmax) of AChE indicated that affinities and hydrolyzing efficiencies of this enzyme in CRSS were higher than SH. Susceptibility to chlorpyrifos in L. sativae was re-gained in the absence of insecticide pressure. Synergism, biochemical and cross-resistance assays revealed that overactivity of metabolic enzymes and reduction in target site sensitivity are probably joint factors in chlorpyrifos resistance. An effective insecticide resistance management program is necessary to prevent fast resistance development in crop systems.
Stonis, Jonas Rimantas; Diskus, Arūnas
Two new species are described from the tropical forest of Belize: Coptotriche singularis (host-plant unknown) and C. forsteroniae (leaf-miner on Forsteronia myriantha, Apocynaceae). The external features and male genitalia are figured and described for both species. A checklist of Coptotriche species comprising 31 species currently known from the Americas is given. Most of the species are known from mainland USA and Canada, and only a few from the Neotropics (the Caribbean and Belize).
Cao, Huan-Xi; La Salle, John; Zhu, Chao-Dong
Abstract The new species Zagrammosoma dulanense Cao & Zhu, sp. n., from Qinghai Province, China, is described and illustrated. All type specimens were reared from the pupae of Micrurapteryx sophorivora Kuznetzov & Tristan (Lepidoptera: Gracillariidae), a leafmining moth attacking the plant Thermopsis lanceolata R. Br. (Fabaceae). A key to the three known Asian species of Zagrammosoma is provided. All specimens are deposited in the Insect Collection, the Institute of Zoology, Chinese Academy of Sciences, Beijing, China. PMID:25061354
Ayabe, Yoshiko; Ueno, Takatoshi
Because insect herbivores generally suffer from high mortality due to their natural enemies, reducing the risk of being located by natural enemies is of critical importance for them, forcing them to develop a variety of defensive measures. Larvae of leaf-mining insects lead a sedentary life inside a leaf and make conspicuous feeding tracks called mines, exposing themselves to the potential risk of parasitism. We investigated the defense strategy of the linear leafminer Ophiomyia maura Meigen (Diptera: Agromyzidae), by focusing on its mining patterns. We examined whether the leafminer could reduce the risk of being parasitized (1) by making cross structures in the inner area of a leaf to deter parasitoids from tracking the mines due to complex pathways, and (2) by mining along the edge of a leaf to hinder visually searching parasitoids from finding mined leaves due to effective background matching of the mined leaves among intact leaves. We quantified fractal dimension as mine complexity and area of mine in the inner area of the leaf as interior mine density for each sample mine, and analyzed whether these mine traits affected the susceptibility of O. maura to parasitism. Our results have shown that an increase in mine complexity with the development of occupying larvae decreases the probability of being parasitized, while interior mine density has no influence on parasitism. These results suggest that the larval development increases the host defense ability through increasing mine complexity. Thus the feeding pattern of these sessile insects has a defensive function by reducing the risk of parasitism.
Ferracini, Chiara; Alma, Alberto
The parasitoid complex associated with the exotic leafminer Cameraria ohridella Deschka and Dimic (Lepidoptera: Gracillariidae), which attacks horse chestnut (Aesculus hippocastanum L.), was studied in the urban environment of Turin (northern Italy). The studies were carried out over 5 yr after the first detection of the pest in our region in 1999. To evaluate parasitism, 438,029 leaf mines were examined over the 5-yr period, of which 29,033 were found to be parasitized (6.6%). Also, ornamental broadleaf trees attacked by other native gracillariid leafminers and located in the proximity of the target horse chestnut trees were sampled. A total of 11 parasitoid species (Hymenoptera: Eulophidae) were recorded on C. ohridella, and the most common species were Minotetrastichus frontalis (Nees), Closterocerus trifasciatus Westwood, and Pnigalio agraules (Walker). The first species accounted for >77.5% of all parasitoids collected. Cirrospilus talitzkii Boucek was found for the first time in 2005. The high population level of the pest and the low parasitism rate show that the parasitoid complex is currently inadequate to contain C. ohridella populations effectively. The most frequent parasitoids of the moth were also found on the most common broadleaf trees in the studied area, showing how native leafminer parasitoid species are able to switch to other hosts. These results show that both native and broadleaf plants species may potentially provide an important reservoir of parasitic wasps to help protect a simple biotope, such as the urban environment, from pests.
Wei, Jianing; Wang, Lizhong; Zhao, Jiuhai; Li, Chuanyou; Ge, Feng; Kang, Le
Recent studies on plants genetically modified in jasmonic acid (JA) signalling support the hypothesis that the jasmonate family of oxylipins plays an important role in mediating direct and indirect plant defences. However, the interaction of two modes of defence in tritrophic systems is largely unknown. In this study, we examined the preference and performance of a herbivorous leafminer (Liriomyza huidobrensis) and its parasitic wasp (Opius dissitus) on three tomato genotypes: a wild-type (WT) plant, a JA biosynthesis (spr2) mutant, and a JA-overexpression 35S::prosys plant. Their proteinase inhibitor production and volatile emission were used as direct and indirect defence factors to evaluate the responses of leafminers and parasitoids. Here, we show that although spr2 mutant plants are compromised in direct defence against the larval leafminers and in attracting parasitoids, they are less attractive to adult flies compared with WT plants. Moreover, in comparison to other genotypes, the 35S::prosys plant displays greater direct and constitutive indirect defences, but reduced success of parasitism by parasitoids. Taken together, these results suggest that there are distinguished ecological trade-offs between JA-dependent direct and indirect defences in genetically modified plants whose fitness should be assessed in tritrophic systems and under natural conditions. PMID:21039561
Sufang, Zhang; Jianing, Wei; Zhen, Zhang; Le, Kang
The release rhythm of volatiles is an important physiological characteristic of plants, because the timing of release can affect the function of each particular volatile compound. However, most studies on volatiles release rhythms have been conducted using model plants, rather than crop plants. Here, we analyzed the variations in volatile compounds released from healthy and leafminer (Liriomyza huidobrensis)-infested kidney bean (Phaseolus vulgaris), an important legume crop plant, over a 24 h period. The constituents of the volatiles mixture released from plants were analyzed every 3 h starting from 08:00. The collected volatiles were identified and quantified by gas chromatography–mass spectrometry. Undamaged kidney bean plants released trace amounts of volatiles, with no obvious release rhythms. However, leafminer-damaged plants released large amounts of volatiles, in two main peaks. The main peak of emission was from 17:00 to 20:00, while the secondary peak was in the early morning. The terpene volatiles and (Z)-3-hexenyl acetate showed similar rhythms as that of total volatiles. However, the green leaf volatile (Z)-3-hexen-ol was emitted during the night with peak emission in the early morning. These results give us a clear picture of the volatiles release rhythms of kidney bean plants damaged by leafminer.
Sufang, Zhang; Jianing, Wei; Zhen, Zhang; Le, Kang
The release rhythm of volatiles is an important physiological characteristic of plants, because the timing of release can affect the function of each particular volatile compound. However, most studies on volatiles release rhythms have been conducted using model plants, rather than crop plants. Here, we analyzed the variations in volatile compounds released from healthy and leafminer (Liriomyza huidobrensis)-infested kidney bean (Phaseolus vulgaris), an important legume crop plant, over a 24 h period. The constituents of the volatiles mixture released from plants were analyzed every 3 h starting from 08:00. The collected volatiles were identified and quantified by gas chromatography–mass spectrometry. Undamaged kidney bean plants released trace amounts of volatiles, with no obvious release rhythms. However, leafminer-damaged plants released large amounts of volatiles, in two main peaks. The main peak of emission was from 17:00 to 20:00, while the secondary peak was in the early morning. The terpene volatiles and (Z)-3-hexenyl acetate showed similar rhythms as that of total volatiles. However, the green leaf volatile (Z)-3-hexen-ol was emitted during the night with peak emission in the early morning. These results give us a clear picture of the volatiles release rhythms of kidney bean plants damaged by leafminer. PMID:23887493
Wei, Jianing; Wang, Lizhong; Zhao, Jiuhai; Li, Chuanyou; Ge, Feng; Kang, Le
Recent studies on plants genetically modified in jasmonic acid (JA) signalling support the hypothesis that the jasmonate family of oxylipins plays an important role in mediating direct and indirect plant defences. However, the interaction of two modes of defence in tritrophic systems is largely unknown. In this study, we examined the preference and performance of a herbivorous leafminer (Liriomyza huidobrensis) and its parasitic wasp (Opius dissitus) on three tomato genotypes: a wild-type (WT) plant, a JA biosynthesis (spr2) mutant, and a JA-overexpression 35S::prosys plant. Their proteinase inhibitor production and volatile emission were used as direct and indirect defence factors to evaluate the responses of leafminers and parasitoids. Here, we show that although spr2 mutant plants are compromised in direct defence against the larval leafminers and in attracting parasitoids, they are less attractive to adult flies compared with WT plants. Moreover, in comparison to other genotypes, the 35S::prosys plant displays greater direct and constitutive indirect defences, but reduced success of parasitism by parasitoids. Taken together, these results suggest that there are distinguished ecological trade-offs between JA-dependent direct and indirect defences in genetically modified plants whose fitness should be assessed in tritrophic systems and under natural conditions.
van Nieukerken, Erik J; Doorenweerd, Camiel; Nishida, Kenji; Snyers, Chris
After finding distinct clades in a molecular phylogeny for Nepticulidae that could not be placed in any known genera and discovering clear apomorphic characters that define these clades, as well as a number of Neotropical species that could be placed in known genera but were undescribed, three new genera and nine new species are here described from the Neotropics: Stigmella gallicola van Nieukerken & Nishida, sp. n. reared from galls on Hampea appendiculata (Malvaceae) in Costa Rica, representing the first example of a gall making Stigmella; Stigmella schinivora van Nieukerken, sp. n. reared from leafmines on Schinus terebinthifolia (Anacardiaceae) in Argentina, Misiones; Stigmella costaricensis van Nieukerken & Nishida, sp. n. and Stigmella intronia van Nieukerken & Nishida, sp. n. each from a single specimen collected the same night in Costa Rica, Parque Nacional Chirripó; Stigmella molinensis van Nieukerken & Snyers, sp. n. reared from leafmines on Salix humboldtiana, Peru, Lima, the first Neotropical species of the Stigmella salicis group sensu stricto; Ozadelpha van Nieukerken, gen. n. with type species Ozadelpha conostegiae van Nieukerken & Nishida, sp. n., reared from leafmines on Conostegia oerstediana (Melastomataceae) from Costa Rica; Neotrifurcula van Nieukerken, gen. n. with type species Neotrifurcula gielisorum van Nieukerken, sp. n. from Chile; Hesperolyra van Nieukerken, gen. n.. with type species Fomoria diskusi Puplesis & Robinson, 2000; Hesperolyra saopaulensis van Nieukerken, sp. n., reared from an unidentified Myrtaceae, Sao Paulo, Brasil; and Acalyptris janzeni van Nieukerken & Nishida, sp. n. from Costa Rica, Guanacaste. Five new combinations are made: Ozadelpha ovata (Puplesis & Robinson, 2000), comb. n. and Ozadelpha guajavae (Puplesis & Diškus, 2002), comb. n., Hesperolyra diskusi (Puplesis & Robinson, 2000), comb. n., Hesperolyra molybditis (Zeller, 1877), comb. n. and Hesperolyra repanda (Puplesis & Diškus, 2002), comb. n. Three
van Nieukerken, Erik J.; Doorenweerd, Camiel; Nishida, Kenji; Snyers, Chris
Abstract After finding distinct clades in a molecular phylogeny for Nepticulidae that could not be placed in any known genera and discovering clear apomorphic characters that define these clades, as well as a number of Neotropical species that could be placed in known genera but were undescribed, three new genera and nine new species are here described from the Neotropics: Stigmella gallicola van Nieukerken & Nishida, sp. n. reared from galls on Hampea appendiculata (Malvaceae) in Costa Rica, representing the first example of a gall making Stigmella; Stigmella schinivora van Nieukerken, sp. n. reared from leafmines on Schinus terebinthifolia (Anacardiaceae) in Argentina, Misiones; Stigmella costaricensis van Nieukerken & Nishida, sp. n. and Stigmella intronia van Nieukerken & Nishida, sp. n. each from a single specimen collected the same night in Costa Rica, Parque Nacional Chirripó; Stigmella molinensis van Nieukerken & Snyers, sp. n. reared from leafmines on Salix humboldtiana, Peru, Lima, the first Neotropical species of the Stigmella salicis group sensu stricto; Ozadelpha van Nieukerken, gen. n. with type species Ozadelpha conostegiae van Nieukerken & Nishida, sp. n., reared from leafmines on Conostegia oerstediana (Melastomataceae) from Costa Rica; Neotrifurcula van Nieukerken, gen. n. with type species Neotrifurcula gielisorum van Nieukerken, sp. n. from Chile; Hesperolyra van Nieukerken, gen. n.. with type species Fomoria diskusi Puplesis & Robinson, 2000; Hesperolyra saopaulensis van Nieukerken, sp. n., reared from an unidentified Myrtaceae, Sao Paulo, Brasil; and Acalyptris janzeni van Nieukerken & Nishida, sp. n. from Costa Rica, Guanacaste. Five new combinations are made: Ozadelpha ovata (Puplesis & Robinson, 2000), comb. n. and Ozadelpha guajavae (Puplesis & Diškus, 2002), comb. n., Hesperolyra diskusi (Puplesis & Robinson, 2000), comb. n., Hesperolyra molybditis (Zeller, 1877), comb. n. and Hesperolyra repanda (Puplesis & Diškus, 2002), comb. n
Kozlov, Mikhail V; Lanta, Vojtěch; Zverev, Vitali; Rainio, Kalle; Kunavin, Mikhail A; Zvereva, Elena L
Despite the increasing rate of urbanisation, the consequences of this process on biotic interactions remain insufficiently studied. Our aims were to identify the general pattern of urbanisation impact on background insect herbivory, to explore variations in this impact related to characteristics of both urban areas and insect-plant systems, and to uncover the factors governing urbanisation impacts on insect herbivory. We compared the foliar damage inflicted on the most common trees by defoliating, leafmining and gall-forming insects in rural and urban habitats associated with 16 European cities. In two of these cities we explored quality of birch foliage for herbivorous insects, mortality of leafmining insects due to predators and parasitoids and bird predation on artificial plasticine larvae. On average, the foliage losses to insects were 16.5% lower in urban than in rural habitats. The magnitude of the overall adverse effect of urbanisation on herbivory was independent of the latitude of the locality and was similar in all 11 studied tree species, but increased with an increase in the size of the urban area: it was significant in large cities (city population 1-5 million) but not significant in medium-sized and small towns. Quality of birch foliage for herbivorous insects was slightly higher in urban habitats than in rural habitats. At the same time, leafminer mortality due to ants and birds and the bird attack intensity on dummy larvae were higher in large cities than in rural habitats, which at least partially explained the decline in insect herbivory observed in response to urbanisation. Our findings underscore the importance of top-down forces in mediating impacts of urbanisation on plant-feeding insects: factors favouring predators may override the positive effects of temperature elevation on insects and thus reduce plant damage. This article is protected by copyright. All rights reserved.
Videla, Martín; Valladares, Graciela R; Salvo, Adriana
Insect preferences for particular plant species might be subjected to trade-offs among several selective forces. Here, we evaluated, through laboratory and field experiments, the feeding and ovipositing preferences of the polyphagous leafminer Liriomyza huidobrensis (Diptera: Agromyzidae) in relation to adult and offspring performance and enemy-free space. Female leafminers preferred laying their eggs on Vicia faba (Fabaceae) over Beta vulgaris var. cicla (Chenopodiaceae), in both laboratory and field choice experiments, although no oviposition preference was observed in no-choice tests. Females fed more often on B. v. var. cicla (no-choice test) or showed no feeding preference (choice test), even when their realized fecundity was remarkably higher on V. faba. Offspring developed faster, tended to survive better, and attained bigger adult size on the preferred host plant. Also, a field experiment showed higher overall parasitism rates for leafminers developing on B. v. var. cicla, with a nonsignificant similar tendency in field surveys. According to these results, host plant selection by L. huidobrensis appears to be driven mainly by variation in host quality. Moreover, the consistent oviposition choices for the best host and the labile feeding preferences observed here, suggest that host plant selection might be driven by maximization of offspring fitness even without a conflict of interest between parents and offspring. Overall, these results highlight the complexity of decisions performed by phytophagous insects regarding their host plants, and the importance of simultaneous evaluation of the various driving forces involved, in order to unravel the adaptive significance of female choices.
Discovery of a new species of Caloptilia (Lepidoptera: Gracillariidae) from east and central Africa with its suggested associated host (Gentianales: Rubiaceae) and natural enemies (Hymenoptera: Eulophidae).
De Prins, Jurate; Gumovsky, Alex; De Coninck, Eliane
A new species of the leaf-mining moth genus Caloptilia (Gracillariidae), C. mwamba sp. nov., suggested to be associated with Cremaspora triflora (Thonn.) K.Schum. (Rubiaceae) is described from east and central Africa. The taxonomic relationships of the new species with its congeners from the Oriental and the Palaearctic regions are discussed. Newly obtained taxonomic and biological data are linked with the DNA barcode workbench in BOLD, providing the molecular, machine-readable identification tag of the new species. New distribution and morphological data for two parasitoid species, Afrotroppopsis risbeci Gumovsky, 2007 and Zaommomentedon newbyi (Kerrich, 1969) (Eulophidae), which were found to be associated with C. mwamba sp. nov., are presented.
Stonis, Jonas R; Remeikis, Andrius; Diškus, Arūnas; Gerulaitis, Virginijus
On the basis of morphological studies of collection samples from the Andes (Ecuador, Peru and Argentina), we describe five new species of Stigmella Schrank (Lepidoptera: Nepticulidae): S. varispinella Diškus & Stonis, sp. nov. (Ecuador), S. olekarsholti Remeikis Diškus & Stonis, sp. nov., S. magnispinella Remeikis & Stonis, sp. nov. (Peru), S. dolia Remeikis & Stonis, sp. nov., and S. patagonica Remeikis & Stonis, sp. nov. (Argentina). All treated taxa belong to the newly designated S. magnispinella group. Images of adults and genitalia, pictorial keys, a distribution map, and photographs of the leaf-mines of S. olekarsholti are included.
Monteiro, Nilton Juvencio Santiago; Carvalho-Filho, Fernando Da Silva; Esposito, Maria Cristina
Japanagromyza sasakawai sp. n. is described from the Brazilian Amazon, based on the male, female, third instar larva and puparium. This species is a leaf-miner of Terminalia catappa L. (Combretaceae), which is an introduced plant from the Old World tropics used in Brazil as an ornamental. The male aedeagus of J. sasakawai sp. n. differs from other species mainly in having the mesophallus covered with many spine-like processes. This is the third record of Japanagromyza Sasakawa in Brazil and first in the Brazilian Amazon. The key to Neotropical species of Japanagromyza by Sousa & Couri (2014) is modified to include this new species.
Borkhataria, R.R.; Collazo, J.A.; Groom, M.J.
A variety of studies have established the value of shaded coffee plantations as habitat for birds. While the value of birds as biological controls in coffee has received some attention, the interactions between birds and other predators of insects have not been tested. We used exclosures to examine the effects of vertebrate predators on the arthropods associated with coffee, in particular the coffee leafminer (Leucoptera coffeella) and the flatid planthopper Petrusa epilepsis, in a shaded coffee plantation in Puerto Rico. We used a 2 x 2 factorial design with four treatments: exclusion of birds, lizards, birds and lizards, and control (no exclusion). Abundance of insects >5 mm increased when birds or both birds and lizards were removed. Birds and lizards had an additive effect for insects <5 mm and for all insects combined. Coffee leafminers showed a weak response to removal of predators while planthopper abundance increased significantly in the absence of avian predators. Arthropod predators and parasitoids did not differ significantly between treatments. Our findings suggest that vertebrate insectivores have an additive effect on insects in coffee and may help control abundances of some coffee pests. Equally important, we present evidence suggesting that they do not interfere with other known natural enemies of coffee pests. ?? 2006 by the Ecological Society of America.
McKee, Fraser R; Levac, Joshua; Hallett, Rebecca H
The pea leafminer, Liriomyza huidobrensis (Diptera: Agromyzidae), is a highly polyphagous insect pest of global distribution. L. huidobrensis feeds and lays its eggs on leaf tissue and reduces crop marketability because of stippling and mining damage. In field insecticide trials, it was observed that stippling was reduced on plants treated with surfactant alone. The objectives of this study were to determine the effect of surfactants on host selection behaviors of female L. huidobrensis and to assess the phytotoxicity of two common surfactants to test plants. The application of the surfactant Sylgard 309 to celery (Apium graveolens) caused a significant reduction in stippling rates. The application of Agral 90 to cucumber leaves (Cucumis sativus) resulted in changes to the amount of effort invested by females in specific host plant selection behaviors, as well as causing a significant reduction in the amount of stippling damage. The recommended dose of Sylgard 309 does not induce phytotoxicity on celery over a range of age classes nor does Agral 90 cause a phytotoxic effect in 35-d-old cucumber. Thus, reductions in observed stippling and changes to host selection behaviors were caused by an antixenotic effect of the surfactant on L. huidobrensis rather than a toxic effect of the surfactant on the plant. The presence of surfactant on an otherwise acceptable host plant seems to have masked host plant cues and prevented host plant recognition. Results indicate that surfactants may be used to reduce leafminer damage to vegetable crops, potentially reducing the use of insecticides.
Zhang, Sufang; Wei, Jianing; Guo, Xiaojiao; Liu, Tong-Xian; Kang, Le
In a tritrophic system formed by a plant, an herbivore and a natural enemy, each component has its own biological rhythm. However, the rhythm correlations among the three levels and the underlying mechanisms in any tritrophic system are largely unknown. Here, we report that the rhythms exhibited bidirectional correlations in a model tritrophic system involving a lima bean, a pea leafminer and a parasitoid. From the bottom-up perspective, the rhythm was initiated from herbivore feeding, which triggered the rhythms of volatile emissions; then the rhythmic pattern of parasitoid activities was affected, and these rhythms were synchronized by a light switch signal. Increased volatile concentration can enhance the intensity of parasitoid locomotion and oviposition only under light. From the top-down perspective, naive and oviposition-experienced parasitoids were able to utilize the different volatile rhythm information from the damaged plant to locate host leafminers respectively. Our results indicated that the three interacting organisms in this system can achieve rhythmic functional synchronization under a natural light-dark photoperiod, but not under constant light or darkness. These findings provide new insight into the rhythm synchronization of three key players that contribute to the utilization of light and chemical signals, and our results may be used as potential approaches for manipulating natural enemies. PMID:20552008
Ditya, Papia; Das, S P; Sarkar, P K; Bhattacharyya, Anjan
Chlorfenapyr is a pyrrole group of insecticide, [4-bromo-2-(4-chlorophenyl)-1-ethoxymethyl-5-trifluoromethyl-1H-pyrrole-3-carbonitrile]used as broad spectrum insecticide/acaricide to control whitefly, thrips, caterpillars, mites, leafminers, aphids, etc., chlorfenapyr 10% SC formulation was applied on chili and cabbage twice @ 75 and 100 g a.i./ha along with untreated control. Chlorfenapyr was dissipated in chili, cabbage and soil following the first-order kinetics (logC/C(0) = -kt). The half lives of chlorfenapyr in chili, cabbage and soil were varying from 2.93 to 2.96 days, 2.98 to 3.62 days and 4.06 to 4.36 days respectively, according to the application rate.
Groen, Simon C.; Humphrey, Parris T.; Chevasco, Daniela; Ausubel, Frederick M.; Pierce, Naomi E.; Whiteman, Noah K.
Plant-herbivore interactions have evolved in the presence of plant-colonizing microbes. These microbes can have important third-party effects on herbivore ecology, as exemplified by drosophilid flies that evolved from ancestors feeding on plant-associated microbes. Leaf-mining flies in the genus Scaptomyza, which is nested within the paraphyletic genus Drosophila, show strong associations with bacteria in the genus Pseudomonas, including Pseudomonas syringae. Adult females are capable of vectoring these bacteria between plants and larvae show a preference for feeding on P. syringae-infected leaves. Here we show that Scaptomyza flava larvae can also vector P. syringae to and from feeding sites, and that they not only feed more, but also develop faster on plants previously infected with P. syringae. Our genetic and physiological data show that P. syringae enhances S. flava feeding on infected plants at least in part by suppressing anti-herbivore defenses mediated by reactive oxygen species. PMID:26205072
Dewan, Rahul; Fischer, Stefan; Meyer-Rochow, V Benno; Özdemir, Yasemin; Hamraz, Saeed; Knipp, Dietmar
Nipples on the surface of moth eye facets exhibit almost perfect broadband anti-reflection properties. We have studied the facet surface micro-protuberances, known as corneal nipples, of the chestnut leafminer moth Cameraria ohridella by atomic force microscopy, and simulated the optics of the nipple arrays by three-dimensional electromagnetic simulation. The influence of the dimensions and shapes of the nipples on the optics was studied. In particular, the shape of the nipples has a major influence on the anti-reflection properties. Furthermore, we transferred the structure of the almost perfect broadband anti-reflection coatings to amorphous silicon thin film solar cells. The coating that imitates the moth-eye array allows for an increase of the short circuit current and conversion efficiency of more than 40%.
Miura, Kazuki; Tagami, Yohsuke; Ohtaishi, Makoto; Iwvasaki, Akeo
A molecular method is applied for differentiating the morphologically related leafminers Liriomyza trifolli and L. sativae on tomato cultivation. The method requires multiplex polymerase chain reaction (PCR) amplification of a region of mitochondrial cytochrome oxidase DNA using multiprimer sets. The method divides the mitochondrial fragment of L. trifolli into two fragments and L. sativae into three fragments. It is faster, less costly, and easier than random amplified polymorphic DNA-PCR, PCR-restriction fragment-length polymorphism, and DNA sequencing and more sensitive than the enzyme electrophoresis method, which are other ways to differentiate these two species. We applied the method to samples from populations of another place, sex, and stage and obtained the same results.
Djemai, I; Casas, J; Magal, C
The sensory ecology of predator detection by prey has been little studied for any arthropod prey predator system, in contrast to the sensory ecology of prey finding by predators. The aim of this study was to quantify the foraging signals produced by the parasitoid Sympiesis sericeicornis (Hymenoptera: Eulophidae) and the sensory ecology of enemy detection and the avoidance behaviour of the leaf-mining host, Phyllonorycter spp. (Lepidoptera: Gracillariidae). We used synthetic vibrations approximating the signals generated by ovipositor insertions to stimulate the host in its mine. Tothe authors' knowledge, this is the first manipulative study to describe a match in the frequency range between a parasitoid foraging stimulus and a host behavioural response. We discuss our findings in relation to other predator-prey systems for which a coevolution between prey sensitivity and predator signal has been described. PMID:11747557
Vogler, Ute; Rott, Anja S; Gessler, Cesare; Dorn, Silvia
While most risk assessments contrast a transgenic resistant to its isogenic line, an additional comparison between the transgenic line and a classically bred cultivar with the same resistance gene would be highly desirable. Our approach was to compare headspace volatiles of transgenic scab resistant apple plants with two representative cultivars (the isogenic 'Gala' and the scab resistance gene-containing 'Florina'). As modifications in volatile profiles have been shown to alter plant relationships with non-target insects, we analysed headspace volatiles from apple plants subjected to different infection types by gas chromatography-mass spectrometry. Marked differences were found between healthy and leafminer (Phyllonorycter blancardella) infested genotypes, where emissions between the transgenic scab resistant line and the two cultivars differed quantitatively in four terpenes and an aromatic compound. However, these modified odour emissions were in the range of variability of the emissions recorded for the two standard cultivars that proved to be crucial references.
Richardson, Matthew L; Mitchell, Robert F; Reagel, Peter F; Hanks, Lawrence M
We review the primary literature to document the incidence of cannibalism among insects that typically are not carnivorous. Most of the cannibalistic species were coleopterans and lepidopterans, and the cannibals often were juveniles that aggregate or that overlap in phenology with the egg stage. Cannibalism can be adaptive by improving growth rate, survivorship, vigor, longevity, and fecundity. It also can play an important role in regulating population density and suppressing population outbreaks, stabilizing host plant-insect relationships, and reducing parasitism rates. Cannibalism often was favored by density-dependent factors for herbivores that feed in concealed feeding situations (such as stem borers, leafminers), but also by density-independent factors (such as high ambient temperature) for herbivores that feed in exposed feeding situations.
Wang, Shuaiyu; Lei, Zhongren; Wen, Jinzeng; Wang, Haihong; Li, Xue; Dong, Baoxin; Ren, Baozhen
Liriomyza huidobrensis, L. trifolii and L. sativae (Diptera: Agromyzidae) are serious horticultural pests. The three species are very similar and difficult to discriminate from each other. In this study, we report the mitochondrial genome of L. huidobrensis and compare with L. trifolii and L. sativae. The mitochondrial genome of L. huidobrensis is 16,239 bp long, and it contains 37 genes and one A + T-rich region as do the sequenced liriomyza species. The sequence and structure of H51-H100 region in srRNA is significantly different from that of L. trifolii and L. sativae. The greatest sequence differences among the three leafminers are located in the region including ND2, ND3, ND6, ATP6, ATP8, CYTb and A+T region, which can be considered as candidate regions for molecular identification or SNP markers.
Scheffer, S J
Phylogenetic relationships among populations of the polyphagous pea leafminer, Liriomyza huidobrensis (Blanchard), were investigated using DNA sequence data. Maximum parsimony analysis of 941 bp of mitochondrial cytochrome oxidase I and II genes showed that L. huidobrensis contains two well-defined monophyletic groups, one composed of specimens from California and Hawaii and one composed of specimens from South and Central America together with populations that have been recently introduced into other parts of the world. The differentiation between the two clades within L. huidobrensis is equivalent to that seen between other agromyzid species, suggesting that L. huidobrensis as currently defined contains two cryptic species. This finding is consistent with field observations of differences in pest status and insecticide resistance between L. huidobrensis populations. Until additional studies are complete, no changes in L. huidobrensis taxonomy are proposed. However, researchers and quarantine officials may wish to consider the findings of the current study in designing research, pest management, and quarantine programs for L. huidobrensis.
Lourenço, I; Rodrigues, S; Figueiredo, E; Godinho, M C; Marques, C; Amaro, F; Mexia, A
This study took place in the Oeste region from 1996-1999 and it intended to analyse if the crop protection strategy followed by the farmer influenced the arthropod incidence and the natural control in protected vegetable crops under Mediterranean conditions. The observations were made fortnightly (Autumn/Winter) or weekly (Spring/Summer) in 30-60 plants/parcel (1 plant/35 m2) in order to evaluate incidences. Samples of pests and natural enemies were collected for systematic identification in two greenhouses for each protection strategy (traditional chemical control (TCC), integrated pest management (IPM) and pest control allowed in organic farming (OF)) in lettuce, tomato, green beans and cucumber. Data on incidence of mites, aphids, caterpillars, leafminers, whiteflies, thrips and respective natural enemies were registered as well as phytosanitary treatments performed (farmers' information and/or in loco traces). The leafminers were the pest whose incidence more often presented significant statistical differences between the studied protection strategies. In relation to this pest, the main results obtained were: a higher feeding punctures incidence in TCC than in IPM; higher incidence of adults, mines and feeding punctures in TCC than in OF; and a higher mines' incidence in IPM than in OF. Both in TCC and IPM high percentages of plants with mines were found although without an adult proportional presence. In the first case this was due to the repeatedly phytosanitary treatments applied; in the second case it was due to the natural control, since in IPM and OF greenhouses the collected larvae were mostly parasitized or dead. In spite of the fact these two strategies have as final result a similar mines and adults incidence, their production and environmental costs are quite different. Significant differences at the beneficials' population level between TCC greenhouses and IPM or OF greenhouses were found. As the farmers did no biological treatments these
Doorenweerd, Camiel; Nieukerken, Erik J Van; Sohn, Jae-Cheon; Labandeira, Conrad C
With phylogenetic knowledge of Lepidoptera rapidly increasing, catalysed by increasingly powerful molecular techniques, the demand for fossil calibration points to estimate an evolutionary timeframe for the order is becoming an increasingly pressing issue. The family Nepticulidae is a species rich, basal branch within the phylogeny of the Lepidoptera, characterized by larval leaf-mining habits, and thereby represents a potentially important lineage whose evolutionary history can be established more thoroughly with the potential use of fossil calibration points. Using our experience with extant global Nepticulidae, we discuss a list of characters that may be used to assign fossil leaf mines to Nepticulidae, and suggest useful methods for classifying relevant fossil material. We present a checklist of 79 records of Nepticulidae representing adult and leaf-mine fossils mentioned in literature, often with multiple exemplars constituting a single record. We provide our interpretation of these fossils. Two species now are included in the collective generic name Stigmellites: Stigmellites resupinata (Krassilov, 2008) comb. nov. (from Ophiheliconoma) and Stigmellites almeidae (Martins-Neto, 1989) comb. nov. (from Nepticula). Eleven records are for the first time attributed to Nepticulidae. After discarding several dubious records, including one possibly placing the family at a latest Jurassic position, we conclude that the oldest fossils likely attributable to Nepticulidae are several exemplars representing a variety of species from the Dakota Formation (USA). The relevant strata containing these earliest fossils are now dated at 102 Ma (million years ago) in age, corresponding to the latest Albian Stage of the Early Cretaceous. Integration of all records in the checklist shows that a continuous presence of nepticulid-like leaf mines preserved as compression-impression fossils and by amber entombment of adults have a fossil record extending to the latest Early Cretaceous.
Background A successful development of herbivorous insects into plant tissues depends on coordination of metabolic processes. Plants have evolved complex mechanisms to recognize such attacks, and to trigger a defense response. To understand the transcriptional basis of this response, we compare gene expression profiles of two coffee genotypes, susceptible and resistant to leaf miner (Leucoptera coffella). A total of 22000 EST sequences from the Coffee Genome Database were selected for a microarray analysis. Fluorescence probes were synthesized using mRNA from the infested and non-infested coffee plants. Array hybridization, scanning and data normalization were performed using Nimble Scan® e ArrayStar® platforms. Genes with foldchange values +/-2 were considered differentially expressed. A validation of 18 differentially expressed genes was performed in infected plants using qRT-PCR approach. Results The microarray analysis indicated that resistant plants differ in gene expression profile. We identified relevant transcriptional changes in defense strategies before insect attack. Expression changes (>2.00-fold) were found in resistant plants for 2137 genes (1266 up-regulated and 873 down-regulated). Up-regulated genes include those responsible for defense mechanisms, hypersensitive response and genes involved with cellular function and maintenance. Also, our analyses indicated that differential expression profiles between resistant and susceptible genotypes are observed in the absence of leaf-miner, indicating that defense is already build up in resistant plants, as a priming mechanism. Validation of selected genes pointed to four selected genes as suitable candidates for markers in assisted-selection of novel cultivars. Conclusions Our results show evidences that coffee defense responses against leaf-miner attack are balanced with other cellular functions. Also analyses suggest a major metabolic reconfiguration that highlights the complexity of this response. PMID
Maunsell, Sarah C; Kitching, Roger L; Burwell, Chris J; Morris, Rebecca J
Gradients in elevation are increasingly used to investigate how species respond to changes in local climatic conditions. Whilst many studies have shown elevational patterns in species richness and turnover, little is known about how food web structure is affected by elevation. Contrasting responses of predator and prey species to elevation may lead to changes in food web structure. We investigated how the quantitative structure of a herbivore-parasitoid food web changes with elevation in an Australian subtropical rain forest. On four occasions, spread over 1 year, we hand-collected leaf miners at twelve sites, along three elevational gradients (between 493 m and 1159 m a.s.l). A total of 5030 insects, including 603 parasitoids, were reared, and summary food webs were created for each site. We also carried out a replicated manipulative experiment by translocating an abundant leaf-mining weevil Platynotocis sp., which largely escaped parasitism at high elevations (≥ 900 m a.s.l.), to lower, warmer elevations, to test if it would experience higher parasitism pressure. We found strong evidence that the environmental change that occurs with increasing elevation affects food web structure. Quantitative measures of generality, vulnerability and interaction evenness decreased significantly with increasing elevation (and decreasing temperature), whilst elevation did not have a significant effect on connectance. Mined plant composition also had a significant effect on generality and vulnerability, but not on interaction evenness. Several relatively abundant species of leaf miner appeared to escape parasitism at higher elevations, but contrary to our prediction, Platynotocis sp. did not experience greater levels of parasitism when translocated to lower elevations. Our study indicates that leaf-mining herbivores and their parasitoids respond differently to environmental conditions imposed by elevation, thus producing structural changes in their food webs. Increasing
Bhattarai, Ganesh P; Meyerson, Laura A; Cronin, James T
Apparent competition, the negative interaction between species mediated by shared natural enemies, is thought to play an important role in shaping the structure and dynamics of natural communities. However, its importance in driving species invasions, and whether the strength of this indirect interaction varies across the latitudinal range of the invasion, has not been fully explored. We performed replicated field experiments at four sites spanning 900 km along the Atlantic Coast of the United States to assess the presence and strength of apparent competition between sympatric native and invasive lineages of Phragmites australis. Four herbivore guilds were considered: stem-feeders, leaf-miners, leaf-chewers and aphids. We also tested the hypothesis that the strength of this interaction declines with increasing latitude. Within each site, native and invasive plants of P. australis were cross-transplanted between co-occurring native and invasive patches in the same marsh habitat and herbivore damage was evaluated at the end of the growing season. Apparent competition was evident for both lineages and involved all but the leaf-chewer guild. For native plants, total aphids per plant was 296% higher and the incidence of stem-feeding and leaf-mining herbivores was 34% and 221% higher, respectively, when transplanted into invasive than native patches. These data suggest that invasive P. australis has a negative effect on native P. australis via apparent competition. Averaged among herbivore types, the indirect effects of the invasive lineage on the native lineage was 57% higher than the reverse situation, suggesting that apparent competition was asymmetric. We also found that the strength of apparent competition acting against the native lineage was comparable to the benefits to the invasive lineage from enemy release (i.e., proportionately lower mean herbivory of the invasive relative to the native taxa). Finally, we found the first evidence that the strength of
Menzel, Annette; Estrella, Nicole; Heitland, Werner; Susnik, Andreja; Schleip, Christoph; Dose, Volker
A recent lengthening of the growing season in mid and higher latitudes of the northern hemisphere is reported as a clear indicator for climate change impacts. Using data from Germany (1951-2003) and Slovenia (1961-2004), we study whether changes in the start, end, and length of the growing season differ among four deciduous broad-leaved tree species and countries, how the changes are related to temperature changes, and what might be the confounding effects of an insect attack. The functional behaviour of the phenological and climatological time series and their trends are not analysed by linear regression, but by a new Bayesian approach taking into account different models for the functional description (one change-point, linear, constant models). We find advanced leaf unfolding in both countries with the same species order (oak > horse chestnut, beech, and birch). However, this advance is non linear over time and more apparent in Germany with clear change-points in the late 1970s, followed by marked advances (on average 3.67 days decade(-1) in the 2000s). In Slovenia, we find a more gradual advance of onset dates (on average 0.8 days decade(-1) in the 2000s). Leaf colouring of birch, beech, and oak has been slightly delayed in the last 3 decades, especially in Germany, however with no clear functional behaviour. Abrupt changes in leaf colouring dates of horse chestnut with recent advancing onset dates can be linked across countries to damage by a newly emerging pest, the horse chestnut leaf-miner (Cameraria ohridella). The lengthening of the growing season, more distinct in Germany than in Slovenia (on average 4.2 and 1.0 days decade(-1) in the 2000s, respectively), exhibits the same species order in both countries (oak > birch > beech). Damage by horse chestnut leaf-miner leads to reduced lengthening (Germany) and drastic shortening (Slovenia) of the horse chestnut growing season (-12 days decade(-1) in the 2000s). Advanced spring leaf unfolding and lengthening
Quah, Shan; Hui, Jerome H L; Holland, Peter W H
MicroRNAs (miRNAs) are involved in posttranscriptional regulation of gene expression. Because several miRNAs are known to affect the stability or translation of developmental regulatory genes, the origin of novel miRNAs may have contributed to the evolution of developmental processes and morphology. Lepidoptera (butterflies and moths) is a species-rich clade with a well-established phylogeny and abundant genomic resources, thereby representing an ideal system in which to study miRNA evolution. We sequenced small RNA libraries from developmental stages of two divergent lepidopterans, Cameraria ohridella (Horse chestnut Leafminer) and Pararge aegeria (Speckled Wood butterfly), discovering 90 and 81 conserved miRNAs, respectively, and many species-specific miRNA sequences. Mapping miRNAs onto the lepidopteran phylogeny reveals rapid miRNA turnover and an episode of miRNA fixation early in lepidopteran evolution, implying that miRNA acquisition accompanied the early radiation of the Lepidoptera. One lepidopteran-specific miRNA gene, miR-2768, is located within an intron of the homeobox gene invected, involved in insect segmental and wing patterning. We identified cubitus interruptus (ci) as a likely direct target of miR-2768, and validated this suppression using a luciferase assay system. We propose a model by which miR-2768 modulates expression of ci in the segmentation pathway and in patterning of lepidopteran wing primordia.
Denys, C; Schmidt, Holger
We studied the ability of insect herbivores and their natural enemies to colonize exposed, potted mugwort plants (Artemisia vulgaris L.) along a rural-urban gradient in 1994 in Hamburg (northern Germany). Ectophagous insects, leafmines and galls were monitored weekly from mid-May to mid-September. Endophagous insects were counted by harvesting and dissecting the stems at the end of the growing season. The rural-urban gradient was characterized by a gradient of vegetation-free areas and increasing proportion of ground covered in concrete, tarmac, paving and other impermeable surfaces surrounding the Artemisia plots, i.e. six different zones of increasing isolation. Numbers of insect species (herbivores, parasitoids and predators) decreased along the gradient from 43 to 12. Monophagous herbivores were not more affected than polyphagous herbivores, but parasitoids, especially rare species, were more strongly affected by isolation than predators. Some dominant herbivorous species were very successful colonizers and occurred in inner city sites devoid of all natural vegetation. Sometimes their abundance increased in the inner city to significantly higher densities than in the urban fringe. Isolation appeared to be the main reason for the observed patterns, since area and soil conditions were held constant in the experiment. Microclimate and pollution were considered to play a minor role.
Cagnolo, Luciano; Valladares, Graciela; Salvo, Adriana; Cabido, Marcelo; Zak, Marcelo
Not all species are likely to be equally affected by habitat fragmentation; thus, we evaluated the effects of size of forest remnants on trophically linked communities of plants, leaf-mining insects, and their parasitoids. We explored the possibility of differential vulnerability to habitat area reduction in relation to species-specific and food-web traits by comparing species-area regression slopes. Moreover, we searched for a synergistic effect of these traits and of trophic level. We collected mined leaves and recorded plant, leaf miner, and parasitoid species interactions in five 100-m2 transects in 19 Chaco Serrano woodland remnants in central Argentina. Species were classified into extreme categories according to body size, natural abundance, trophic breadth, and trophic level. Species-area slopes differed between groups with extreme values of natural abundance or trophic specialization. Nevertheless, synergistic effects of life-history and food-web traits were only found for trophic level and trophic breadth: area-related species loss was highest for specialist parasitoids. It has been suggested that species position within interaction webs could determine their vulnerability to extinction. Our results provide evidence that food-web parameters, such as trophic level and trophic breadth, affect species sensitivity to habitat fragmentation.
Goldman-Huertas, Benjamin; Mitchell, Robert F; Lapoint, Richard T; Faucher, Cécile P; Hildebrand, John G; Whiteman, Noah K
Herbivory is a key innovation in insects, yet has only evolved in one-third of living orders. The evolution of herbivory likely involves major behavioral changes mediated by remodeling of canonical chemosensory modules. Herbivorous flies in the genus Scaptomyza (Drosophilidae) are compelling species in which to study the genomic architecture linked to the transition to herbivory because they recently evolved from microbe-feeding ancestors and are closely related to Drosophila melanogaster. We found that Scaptomyza flava, a leaf-mining specialist on plants in the family (Brassicaceae), was not attracted to yeast volatiles in a four-field olfactometer assay, whereas D. melanogaster was strongly attracted to these volatiles. Yeast-associated volatiles, especially short-chain aliphatic esters, elicited strong antennal responses in D. melanogaster, but weak antennal responses in electroantennographic recordings from S. flava. We sequenced the genome of S. flava and characterized this species' odorant receptor repertoire. Orthologs of odorant receptors, which detect yeast volatiles in D. melanogaster and mediate critical host-choice behavior, were deleted or pseudogenized in the genome of S. flava. These genes were lost step-wise during the evolution of Scaptomyza. Additionally, Scaptomyza has experienced gene duplication and likely positive selection in paralogs of Or67b in D. melanogaster. Olfactory sensory neurons expressing Or67b are sensitive to green-leaf volatiles. Major trophic shifts in insects are associated with chemoreceptor gene loss as recently evolved ecologies shape sensory repertoires.
Bawin, Thomas; Collard, France; De Backer, Lara; Yarou, Boni Barthélémy; Compère, Philippe; Francis, Frédéric; Verheggen, François J
The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread devastating pest that develops on tomato and other economically important solanaceous crops. Current semiochemically-based management strategies still fail to significantly reduce damages and need to be improved. Here we describe under scanning and transmission electron microscopy the structure and distribution of the sensilla that are displayed on adult antennae. These were similar in size between males (3424.4±135.3μm) and females (3292.1±111.5μm), being segmented into a scape, a pedicel, and a distal filiform flagellum. Eight morphological sensilla types were observed on both sexes: Böhm's bristles, sensilla squamiformia, sensilla trichodea, sensilla basiconica (two subtypes), sensilla chaetica, sensilla coeloconica, sensilla auricillica, and sensilla styloconica. The main sexual dimorphism was related to the higher abundance of sensilla trichodea in males, twice as abundant as in females. The putative functional significance of the different sensilla types regarding the insect ecology is discussed based on the available literature. This work provides descriptions of the antennae and related sensory structures. We expect these results to help develop further electrophysiological investigations aiming to a better understanding of T. absoluta olfaction.
Sylla, Serigne; Brévault, Thierry; Diarra, Karamoko; Bearez, Philippe; Desneux, Nicolas
Macrolophus pygmaeus Rambur (Hemiptera: Miridae) is a generalist predatory mirid widely used in augmentative biological control of various insect pests in greenhouse tomato production in Europe, including the invasive tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera, Gelechiidae). However, its biocontrol efficacy often relies on the presence of alternative prey. The present study aimed at evaluating the effect of various prey foods (Ephestia kuehniella eggs, Bemisia tabaci nymphs, Tuta absoluta eggs and Macrosiphum euphorbiae nymphs) on some life history traits of M. pygmaeus. Both nymphal development and adult fertility of M. pygmaeus were significantly affected by prey food type, but not survival. Duration of nymphal stage was higher when M. pygmaeus fed on T. absoluta eggs compared to the other prey. Mean fertility of M. pygmaeus females was greatest when fed with B. tabaci nymphs, and was greater when offered M. euphorbiae aphids and E. kuehniella eggs than when offered T. absoluta eggs. Given the low quality of T. absoluta eggs, the efficacy of M. pygmaeus to control T. absoluta may be limited in the absence of other food sources. Experiments for assessing effectiveness of generalist predators should involve the possible impact of prey preference as well as a possible prey switching. PMID:27870857
Agboton, C; Onzo, A; Ouessou, F I; Goergen, G; Vidal, S; Tamò, M
Cashew, Anacardium occidentale L. (Sapindales: Anacardiaceae), is an important cash crop in Benin. However, its production is threatened by several biotic factors, especially insects. In Benin, very few studies have focused on insects and just listed species commonly found on cashew worldwide. The present investigation fills this gap by presenting an exhaustive inventory of insect species associated with this crop in the country. The survey was carried out from September 2009 to August 2010 in 22 cashew orchards (5 young and 17 mature) distributed over three major agroecological zones where cashew is most produced in the country. Insects were collected using chemical knock-down technique and visual observation followed by capture with sweep net. In addition, infested plant organs were sampled and incubated to collect emerging insects. In total, 262 insect species were recorded and identified. Among them, the wood borer Apate terebrans Pallas, the leafminer Eteoryctis gemoniella Stainton, and the mirid bugs Helopeltis schoutedeni Reuter., and Helopeltis anacardii Miller., appeared as the most important insect species attacking cashew in Benin. Beneficial insects encountered included some predators, parasitoids, and pollinators. Few vertebrate predators were also recorded on the trees. Differences in agroecological conditions or in field cleanliness did not affect the number of insect species encountered in the cashew orchards. The results of this study represent an important baseline data for the design and implementation of strategies for cashew protection in Benin.
Ferracini, Chiara; Alma, Alberto
A fixed precision sequential sampling plan for estimating the density of the horse chestnut, Aesculus hippocastanum L., leafminer Cameraria ohridella Deschka & Dimic (Lepidoptera: Gracillariidae) was developed. Data were collected from 2002 to 2004 in Turin, northwestern Italy, with the aim of developing a sampling strategy for estimating populations of C. ohridella mines. Taylor's power law was used as a regression model. Sampling parameters were estimated from 216 data sets, and an additional 110 independent data sets were used to validate the fixed precision sequential sampling plan with resampling software. Covariance analysis indicated that there were not significant differences in the coefficient of Taylor's power law between heights of the foliage, months, and years. Dispersion patterns of C. ohridella were determined to be aggregated. The parameters of the Taylor's power law were used to calculate minimum sample sizes and sampling stop lines for different precision levels. Considering a mean density value of five mines per leaf, an average sample number of only 49 leaves was necessary to achieve a desired precision level of 0.25. As the precision level was increased to 0.10, the average sample size increased to 303 leaves. The sequential sampling plan should provide an effective management of C. ohridella in the urban areas, minimizing sampling time and cost, and at the same should be an effective tool to reduce insecticide applications and prevent the esthetic damage.
Ishibashi, N.; Choi, D-R.
In greenhouse experiments, massive application of the fungivorous nematode, Aphelenchus avenae, in summer at 26-33 C (1 x l0⁵ nematodes/500 cm³ autoclaved soil) or in autumn at 18-23 C (5 x 10⁴ nematodes/500 cm³ autoclaved soil) suppressed pre-emergence damping-off of cucumber seedlings due to Rhizoctonia solani AG-4 by 67% or 87%, respectively. Application of 2 x l0⁵ A. avenae to sterilized soil infested with R. solani caused leafminer-like symptom on the cotyledons, which did not occur in mixed inoculations with the entomopathogenic nematode, Steinernema carpocapsae. When 1 x 10⁶ A. avenae were applied 3 days before inoculation with 100 Meloidogyne incognita juveniles, gall numbers on tomato roots were reduced to 50% of controls. Gall numbers also were suppressed by S. carpocapsae (str. All). Reduction in gall numbers was no greater with mixed application of A. avenae and S. carpocapsae than with application of single species, even though twice the number of nematodes were added in the former case. These nematodes were positively attracted to tomato root tips. Aphelenchus avenae suppressed infection of the turnip moth, Agrotis segetum, but not the common cutworm, Spodoptera litura, by S. carpocapsae. PMID:19283109
This research evaluated the impacts of herbivorous insects, emphasizing the locust twig borer, Ecdytolopha insiticiana Zeller, on black locust, Robinia pseudoacacia L., coppice production on a coal surface-mine spoil site in southeastern Kentucky. The natural history of E. insiticiana was also studied. The locust twig borer was a persistent and damaging pest in first-year coppice, which provided suitable larval habitat throughout the growing season. The locust leafminer, Odontota dorsalis (Thunberg), fed minimally on first-year coppice foliage except during 1983, when trees were severely drought-stressed. Soil-applied granular carbofuran significantly reduced infestations. Lindane stem treatments were not effective, but entire-tree applications did reduce herbivory. Stump sprouts with reduced levels of herbivory grew significantly taller than controls at both spacings in 1983, but only at the more dense spacing in 1984. Blacklight trap collections revealed two generations/year, and adults were present from early May until late August. Four species of hymenopterous and two species of dipterous parasitoids were recovered from E. insiticiana larvae.
Casteels, H; Hubrechts, W; Desmet, D
Due to residues on the witloof chicory heads the use of insecticides is forbidden during forcing. At this moment a suitable chemical control of the leafminer Napomyza cichorii is carried out in the field, based on the phenology and the population density and taking into account the economic threshold level. No chemical treatment is recognized against the root aphid Pemphigus bursarius. For monitoring these pests during the growing season water traps were placed on observation fields, scattered over the Belgian endive production area. The large numbers and the wide variety of other insects caught in the traps in recent years indicate that there is a potential of natural enemies. An inventarisation of the native enemies in witloof chicory fields was started recently using yellow-coloured water traps and pitfall traps; at the same time field observations were done. In all the observation fields we found besides Carabidae and Staphilinidae also Coccinellidae and Syrphidae in large numbers. The numbers and the diversity of Hymenoptera in the water traps were very large. Apart from the field observations witloof chicory heads were investigated during harvest. Parasitized pupae were collected and kept in a climate room. Dacnusa leptogaster (Braconidae), a specific parasite of the witloof chicory fly, hatched. This parasite was also found in the water traps during the growing season.
Quah, Shan; Hui, Jerome H.L.; Holland, Peter W.H.
MicroRNAs (miRNAs) are involved in posttranscriptional regulation of gene expression. Because several miRNAs are known to affect the stability or translation of developmental regulatory genes, the origin of novel miRNAs may have contributed to the evolution of developmental processes and morphology. Lepidoptera (butterflies and moths) is a species-rich clade with a well-established phylogeny and abundant genomic resources, thereby representing an ideal system in which to study miRNA evolution. We sequenced small RNA libraries from developmental stages of two divergent lepidopterans, Cameraria ohridella (Horse chestnut Leafminer) and Pararge aegeria (Speckled Wood butterfly), discovering 90 and 81 conserved miRNAs, respectively, and many species-specific miRNA sequences. Mapping miRNAs onto the lepidopteran phylogeny reveals rapid miRNA turnover and an episode of miRNA fixation early in lepidopteran evolution, implying that miRNA acquisition accompanied the early radiation of the Lepidoptera. One lepidopteran-specific miRNA gene, miR-2768, is located within an intron of the homeobox gene invected, involved in insect segmental and wing patterning. We identified cubitus interruptus (ci) as a likely direct target of miR-2768, and validated this suppression using a luciferase assay system. We propose a model by which miR-2768 modulates expression of ci in the segmentation pathway and in patterning of lepidopteran wing primordia. PMID:25576364
Stonis, Jonas Rimantas; Diskus, Arūnas
We describe Tischeria gouaniae sp. n. from the tropical forests of Belize. The new species is a leaf-miner of Gouania polygama (Rhamnaceae). Together with the related T. bifurcata Braun, it is among the most striking representatives of Tischeria. Both species possess a pseudognathos and very broad aedeagus fused with extremely long lateral processes of the juxta. The new species differs from T. bifurcata in the broadly rounded vinculum, spiny juxta, and slender apical processes of the aedeagus, and in its host plant. The external features and male genitalia of Tischeria gouaniae sp. n. are figured and described. A checklist and distribution map for all nine currently known Tischeria species from North and South America are given. Most American species are known from USA, but others are now known from tropical forest habitats of Central America, the Caribbean, and Guyana. Host-plants are known for five of the nine species reviewed here, belonging to four genera and two plant families (Fagaceae and Rhamnaceae).
Kirichenko, Natalia; Triberti, Paolo; Mutanen, Marko; Magnoux, Emmanuelle; Landry, Jean-François; Lopez-Vaamonde, Carlos
During a DNA barcoding campaign of leaf-mining insects from Siberia, a genetically divergent lineage of a gracillariid belonging to the genus Micrurapteryx was discovered, whose larvae developed on Caragana Fabr. and Medicago L. (Fabaceae). Specimens from Siberia showed similar external morphology to the Palearctic Micrurapteryx gradatella and the Nearctic Parectopa occulta but differed in male genitalia, DNA barcodes, and nuclear genes histone H3 and 28S. Members of this lineage are re-described here as Micrurapteryx caraganella (Hering, 1957), comb. n., an available name published with only a brief description of its larva and leaf mine. Micrurapteryx caraganella is widely distributed throughout Siberia, from Tyumen oblast in the West to Transbaikalia in the East. Occasionally it may severely affect its main host, Caragana arborescens Lam. This species has been confused in the past with Micrurapteryx gradatella in Siberia, but field observations confirm that Micrurapteryx gradatella exists in Siberia and is sympatric with Micrurapteryx caraganella, at least in the Krasnoyarsk region, where it feeds on different host plants (Vicia amoena Fisch. and Vicia sp.). In addition, based on both morphological and molecular evidence as well as examination of type specimens, the North American Parectopa occulta Braun, 1922 and Parectopa albicostella Braun, 1925 are transferred to Micrurapteryx as Micrurapteryx occulta (Braun, 1922), comb. n. with albicostella as its junior synonym (syn. n.). Characters used to distinguish Micrurapteryx from Parectopa are presented and illustrated. These findings provide another example of the potential of DNA barcoding to reveal overlooked species and illuminate nomenclatural problems.
Huang, Li-Hua; Chen, Bing; Kang, Le
The pea leafminer, Liriomyza huidobrensis, is one of the most important economic insect pests around the world. Its population fluctuates greatly with seasonal change in China, and temperature was thought to be one of the important reasons. In attempt to further explore the impact of disadvantageous temperature on L. huidobrensis, 1-day-old adults were shocked at various temperatures (10, 25, 32, and 35 degrees C, respectively) for 4h, and the effects on thermotolerance, feeding, and fecundity were studied. Meanwhile the expression of five heat shock genes (hsp90, 70, 60, 40, and 20) was examined by real-time quantitative PCR. Our results showed that both 32 and 35 degrees C hardenings remarkably increased adult heat resistance, whereas cold tolerance was not improved accordingly. No cross resistance in response to cold and heat stresses was observed. Both adult feeding and fecundity were dramatically reduced, but no effect was observed on egg hatching, larval survival, pupal eclosion, or sex ratio. The results indicate that the deleterious effect on fecundity is the result of direct cessation of oviposition during the period of stress. Simultaneously, the mRNA levels of hsp70 and hsp20 significantly increased upon thermal hardening. Taken together, our results suggest that mild heat hardening improves thermotolerance of L. huidobrensis at the cost of impairment on fecundity, and the induced expression of hsp70 and hsp20 may play an important role in balancing the functional tradeoff.
Al-Zyoud, Firas Ahmad
This study aimed to determine Serangium parcesetosum preference for different prey species and parasitized Bemisia tabaci (Genn.) (Hom., Aleyrodidae) by the parasitoid, Eretmocerus mundus Mercet (Hym., Aphelinidae). The results on S. parcesetosum preference by feeding on different prey species offered separately and together indicated that the predatory larvae and adults preferred significantly the cotton whitefly, B. tabaci and the castor bean whitefly, Trialeurodes ricini (Misra) (Hom., Aleyrodidae) rather than the two-spotted spider mite, Tetranychus urticae Koch (Acari, Tetranychidae); melon aphid, Aphis gossypii Glover (Hom., Aphididae) and pea leafminer, Liriomyza huidobrensis (Blanchard) (Dip., Agromyzidae). The results on S. parcesetosum preference for the whitefly species, B. tabaci and T. ricini demonstrated that there were no significant differences in the preference of both predatory larvae and adults for any whitefly species. Moreover, S. parcesetosum larvae and adults were significantly tended to avoid parasitized puparia of B. tabaci by E. mundus and fed instead on unparasitized ones. Thus, there is a feasible potential for integration the predator and the parasitoid into a biological control program to suppress B. tabaci.
Masetti, Antonio; Luchetti, Andrea; Mantovani, Barbara; Burgio, Giovanni
The pea leafminer, Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae), is a serious insect pest infesting open field lettuce plantings in northern Italy. In these cropping systems, it coexists with several other agromyzid species that have negligible economic importance on open field vegetables. The rapid detection of L. huidobrensis is crucial for effective management strategies, but the identification of agromyzids to species can be very difficult at adult as well at immature stages. In this study, a polymerase chain reaction (PCR)-restriction fragment length polymorphism assay is proposed to separate L. huidobrensis from Liriomyza bryoniae (Kaltenbach), Liriomyza trifolii (Burgess), and Chromatomyia horticola (Goureau), which usually occur in the same lettuce plantings. An approximately 1,031-bp region of the mitochondrial genome encompassing the 3' region of cytochrome oxidase I, the whole leucine tRNA, and all of the cytochrome oxidase II was amplified by PCR and digested using the enzymes PvuII and SnaBI separately. Both endonucleases cut the amplicons of L. huidobrensis in two fragments, whereas the original band was not cleaved in the other analyzed species. The presence of Dacnusa spp. DNA does not bias the assay, because the PCR conditions and the primer set here described do not amplify any tract of this endoparasitic wasp genome.
Ishaaya, Isaac; Kontsedalov, Svetlana; Horowitz, A Rami
Emamectin is a macrocyclic lactone insecticide with low toxicity to non-target organisms and the environment, and is considered an important component in pest-management programmes for controlling field crop pests. It is a powerful compound for controlling the cotton bollworm Helicoverpa armigera (Hübner). A spray concentration of 25 mg AI litre-1 in a cotton field resulted in over 90% suppression of H armigera larvae up to day 28 after treatment, while similar mortality of the Egyptian cotton leafworm Spodoptera littoralis Boisduval, under the same conditions, was maintained for 3 days only. Emamectin is a potent compound for controlling the western flower thrips Frankliniella occidentalis (Pergande) under both laboratory and field conditions and its activity on adults was over 10-fold greater than that of abamectin. Spray concentrations of 10 and 50 mg AI litre-1 in Ageratum houstonianum Mill flowers resulted in total suppression of adults up to day 11 and of larvae up to day 20 after treatment. Under standard laboratory conditions, emamectin exhibits a considerable activity on the whitefly Bemisia tabaci (Gennadius) and the leafminer Liriomyza huidobrensis (Blanchard). Further studies are required to evaluate its potential activity on the latter pests under field conditions.
Morgan, D J; Reitz, S R; Atkinson, P W; Trumble, J T
Liriomyza trifolii (Burgess) and Liriomyza huidobrensis (Blanchard) are important vegetable pests in California. Populations of each species differ in their impact in central and southern regions. This difference may be explained by geographical or host plant differences in each of the regions. We used random amplified polymorphic DNA polymerase chain reactions to assess genetic differences between two laboratory populations of each species collected from central and southern California. Individual L. trifolii from the two regions could be discriminated by the presence/absence of PCR products. No such qualitative differences were apparent in PCR products amplified from L. huidobrensis individuals, but the origins of individuals could be differentiated using a bootstrap analysis of marker frequencies. Marker primers were used to compare field and laboratory individuals. No evidence was found for the existence of further populations or of hybrid populations in central and southern California. The distribution of populations of L. huidobrensis was explained completely by geographical differences. As a consequence of the absence of leafminer infestations on the same host plant varieties in both regions, factors governing L. trifolii population distribution differences were less apparent. The presence of the same host plant varieties at both sites suggests that the two L. trifolii populations differ in host plant preference.
Campos-Navarrete, María José; Abdala-Roberts, Luis; Munguía-Rosas, Miguel A; Parra-Tabla, Víctor
Plant diversity can influence predators and omnivores and such effects may in turn influence herbivores and plants. However, evidence for these ecological feedbacks is rare. We evaluated if the effects of tree species (SD) and genotypic diversity (GD) on the abundance of different guilds of insect herbivores associated with big-leaf mahogany (Swietenia macrophylla) were contingent upon the protective effects of ants tending extra-floral nectaries of this species. This study was conducted within a larger experiment consisting of mahogany monocultures and species polycultures of four species and -within each of these two plot types- mahogany was represented by either one or four maternal families. We selected 24 plots spanning these treatment combinations, 10 mahogany plants/plot, and within each plot experimentally reduced ant abundance on half of the selected plants, and surveyed ant and herbivore abundance. There were positive effects of SD on generalist leaf-chewers and sap-feeders, but for the latter group this effect depended on the ant reduction treatment: SD positively influenced sap-feeders under ambient ant abundance but had no effect when ant abundance was reduced; at the same time, ants had negative effects on sap feeders in monoculture but no effect in polyculture. In contrast, SD did not influence specialist stem-borers or leaf-miners and this effect was not contingent upon ant reduction. Finally, GD did not influence any of the herbivore guilds studied, and such effects did not depend on the ant treatment. Overall, we show that tree species diversity influenced interactions between a focal plant species (mahogany) and ants, and that such effects in turn mediated plant diversity effects on some (sap-feeders) but not all the herbivores guilds studied. Our results suggest that the observed patterns are dependent on the combined effects of herbivore identity, diet breadth, and the source of plant diversity.
Kirichenko, Natalia; Triberti, Paolo; Mutanen, Marko; Magnoux, Emmanuelle; Landry, Jean-François; Lopez-Vaamonde, Carlos
Abstract During a DNA barcoding campaign of leaf-mining insects from Siberia, a genetically divergent lineage of a gracillariid belonging to the genus Micrurapteryx was discovered, whose larvae developed on Caragana Fabr. and Medicago L. (Fabaceae). Specimens from Siberia showed similar external morphology to the Palearctic Micrurapteryx gradatella and the Nearctic Parectopa occulta but differed in male genitalia, DNA barcodes, and nuclear genes histone H3 and 28S. Members of this lineage are re-described here as Micrurapteryx caraganella (Hering, 1957), comb. n., an available name published with only a brief description of its larva and leaf mine. Micrurapteryx caraganella is widely distributed throughout Siberia, from Tyumen oblast in the West to Transbaikalia in the East. Occasionally it may severely affect its main host, Caragana arborescens Lam. This species has been confused in the past with Micrurapteryx gradatella in Siberia, but field observations confirm that Micrurapteryx gradatella exists in Siberia and is sympatric with Micrurapteryx caraganella, at least in the Krasnoyarsk region, where it feeds on different host plants (Vicia amoena Fisch. and Vicia sp.). In addition, based on both morphological and molecular evidence as well as examination of type specimens, the North American Parectopa occulta Braun, 1922 and Parectopa albicostella Braun, 1925 are transferred to Micrurapteryx as Micrurapteryx occulta (Braun, 1922), comb. n. with albicostella as its junior synonym (syn. n.). Characters used to distinguish Micrurapteryx from Parectopa are presented and illustrated. These findings provide another example of the potential of DNA barcoding to reveal overlooked species and illuminate nomenclatural problems. PMID:27110203
Gotsch, Sybil G; Crausbay, Shelley D; Giambelluca, Thomas W; Weintraub, Alexis E; Longman, Ryan J; Asbjornsen, Heidi; Hotchkiss, Sara C; Dawson, Todd E
The goal of this study was to determine the effects of atmospheric demand on both plant water relations and daily whole-tree water balance across the upper limit of a cloud forest at the mean base height of the trade wind inversion in the tropical trade wind belt. We measured the microclimate and water relations (sap flow, water potential, stomatal conductance, pressure-volume relations) of Metrosideros polymorpha Gaudich. var. polymorpha in three habitats bracketing the cloud forest's upper limit in Hawai'i to understand the role of water relations in determining ecotone position. The subalpine shrubland site, located 100 m above the cloud forest boundary, had the highest vapor pressure deficit, the least amount of rainfall and the highest levels of nighttime transpiration (EN) of all three sites. In the shrubland site, on average, 29% of daily whole-tree transpiration occurred at night, while on the driest day of the study 50% of total daily transpiration occurred at night. While EN occurred in the cloud forest habitat, the proportion of total daily transpiration that occurred at night was much lower (4%). The average leaf water potential (Ψleaf) was above the water potential at the turgor loss point (ΨTLP) on both sides of the ecotone due to strong stomatal regulation. While stomatal closure maintained a high Ψleaf, the minimum leaf water potential (Ψleafmin) was close to ΨTLP, indicating that drier conditions may cause drought stress in these habitats and may be an important driver of current landscape patterns in stand density.
Novotny, Vojtech; Basset, Yves
Studies of host specificity in tropical insect herbivores are evolving from a focus on insect distribution data obtained by canopy fogging and other mass collecting methods, to a focus on obtaining data on insect rearing and experimentally verified feeding patterns. We review this transition and identify persisting methodological problems. Replicated quantitative surveys of plant-herbivore food webs, based on sampling efforts of an order of magnitude greater than is customary at present, may be cost-effectively achieved by small research teams supported by local assistants. Survey designs that separate historical and ecological determinants of host specificity by studying herbivores feeding on the same plant species exposed to different environmental or experimental conditions are rare. Further, we advocate the use of host-specificity measures based on plant phylogeny. Existing data suggest that a minority of species in herbivore communities feed on a single plant species when alternative congeneric hosts are available. Thus, host plant range limits tend to coincide with those of plant genera, rather than species or suprageneric taxa. Host specificity among tropical herbivore guilds decreases in the sequence: granivores > leaf-miners > fructivore > leaf-chewers = sap-suckers > xylophages > root-feeders, thus paralleling patterns observed in temperate forests. Differences in host specificity between temperate and tropical forests are difficult to assess since data on tropical herbivores originate from recent field studies, whereas their temperate counterparts derive from regional host species lists, assembled over many years. No major increase in host specificity from temperate to tropical communities is evident. This conclusion, together with the recent downward revisions of extremely high estimates of tropical species richness, suggest that tropical ecosystems may not be as biodiverse as previously thought.
Guiguet, Antoine; Dubreuil, Géraldine; Harris, Marion O; Appel, Heidi M; Schultz, Jack C; Pereira, Marcos H; Giron, David
Insects that reprogram host plants during colonization remind us that the insect side of plant-insect story is just as interesting as the plant side. Insect effectors secreted by the salivary glands play an important role in plant reprogramming. Recent discoveries point to large numbers of salivary effectors being produced by a single herbivore species. Since genetic and functional characterization of effectors is an arduous task, narrowing the field of candidates is useful. We present ideas about types and functions of effectors from research on blood-feeding parasites and their mammalian hosts. Because of their importance for human health, blood-feeding parasites have more tools from genomics and other - omics than plant-feeding parasites. Four themes have emerged: (1) mechanical damage resulting from attack by blood-feeding parasites triggers "early danger signals" in mammalian hosts, which are mediated by eATP, calcium, and hydrogen peroxide, (2) mammalian hosts need to modulate their immune responses to the three "early danger signals" and use apyrases, calreticulins, and peroxiredoxins, respectively, to achieve this, (3) blood-feeding parasites, like their mammalian hosts, rely on some of the same "early danger signals" and modulate their immune responses using the same proteins, and (4) blood-feeding parasites deploy apyrases, calreticulins, and peroxiredoxins in their saliva to manipulate the "danger signals" of their mammalian hosts. We review emerging evidence that plant-feeding insects also interfere with "early danger signals" of their hosts by deploying apyrases, calreticulins and peroxiredoxins in saliva. Given emerging links between these molecules, and plant growth and defense, we propose that these effectors interfere with phytohormone signaling, and therefore have a special importance for gall-inducing and leaf-mining insects, which manipulate host-plants to create better food and shelter.
Camargo, Roberto A.; Barbosa, Guilherme O.; Possignolo, Isabella Presotto; Peres, Lazaro E. P.; Lam, Eric; Lima, Joni E.
RNA interference (RNAi), a gene-silencing mechanism that involves providing double-stranded RNA molecules that match a specific target gene sequence, is now widely used in functional genetic studies. The potential application of RNAi-mediated control of agricultural insect pests has rapidly become evident. The production of transgenic plants expressing dsRNA molecules that target essential insect genes could provide a means of specific gene silencing in larvae that feed on these plants, resulting in larval phenotypes that range from loss of appetite to death. In this report, we show that the tomato leafminer (Tuta absoluta), a major threat to commercial tomato production, can be targeted by RNAi. We selected two target genes (Vacuolar ATPase-A and Arginine kinase) based on the RNAi response reported for these genes in other pest species. In view of the lack of an artificial diet for T. absoluta, we used two approaches to deliver dsRNA into tomato leaflets. The first approach was based on the uptake of dsRNA by leaflets and the second was based on “in planta-induced transient gene silencing” (PITGS), a well-established method for silencing plant genes, used here for the first time to deliver in planta-transcribed dsRNA to target insect genes. Tuta absoluta larvae that fed on leaves containing dsRNA of the target genes showed an ∼60% reduction in target gene transcript accumulation, an increase in larval mortality and less leaf damage. We then generated transgenic ‘Micro-Tom’ tomato plants that expressed hairpin sequences for both genes and observed a reduction in foliar damage by T. absoluta in these plants. Our results demonstrate the feasibility of RNAi as an alternative method for controlling this critical tomato pest. PMID:27994959
Chailleux, Anaïs; Biondi, Antonio; Han, Peng; Tabone, Elisabeth; Desneux, Nicolas
The South American tomato leafminer, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), is a major pest that has recently invaded Afro-Eurasia. Biological control, especially by Trichogramma parasitoids, is considered to be promising as a management tool for this pest. However, further development of Trichogramma-based biocontrol strategies would benefit from assessing the impact of released parasitoid offspring on the pest. Under laboratory conditions, we 1) compared the parasitism of five Trichogramma species-strains on the pest-plant system T. absoluta-tomato, and 2) assessed various biological traits of parasitoids, mass-reared on a factitious host (Ephestia kuehniella Zeller), when developing on T. absoluta. In addition, we evaluated the overall efficiency of two specific Trichogramma species when released under greenhouse conditions in combination with a common natural enemy in tomato crop, the predator Macrolophus pygmaeus Rambur. Parasitoids emerging from T. absoluta on tomato showed lower parasitism rates and poor biological traits, for example, wing deformations, reduced longevity, when compared with the control reared on the factitious host. Under greenhouse conditions, the parasitoids that developed on T. absoluta after initial releases contributed little to biological control of T. absoluta, and parasitism tended to be lower when the predator was present. However, a slightly higher T. absoluta control level was achieved by combining the predator and release of the parasitoid Trichogramma achaeae Nagaraja and Nagarkatti. This study shows that Trichogramma parasitoids may not build up populations on the T. absoluta-tomato system, but that Trichogramma parasitoids can be used in combination with M. pygmaeus to enhance biological control of the pest in tomato crops.
Gossner, Martin M; Pašalić, Esther; Lange, Markus; Lange, Patricia; Boch, Steffen; Hessenmöller, Dominik; Müller, Jörg; Socher, Stephanie A; Fischer, Markus; Schulze, Ernst-Detlef; Weisser, Wolfgang W
Forest management not only affects biodiversity but also might alter ecosystem processes mediated by the organisms, i.e. herbivory the removal of plant biomass by plant-eating insects and other arthropod groups. Aiming at revealing general relationships between forest management and herbivory we investigated aboveground arthropod herbivory in 105 plots dominated by European beech in three different regions in Germany in the sun-exposed canopy of mature beech trees and on beech saplings in the understorey. We separately assessed damage by different guilds of herbivores, i.e. chewing, sucking and scraping herbivores, gall-forming insects and mites, and leaf-mining insects. We asked whether herbivory differs among different forest management regimes (unmanaged, uneven-aged managed, even-aged managed) and among age-classes within even-aged forests. We further tested for consistency of relationships between regions, strata and herbivore guilds. On average, almost 80% of beech leaves showed herbivory damage, and about 6% of leaf area was consumed. Chewing damage was most common, whereas leaf sucking and scraping damage were very rare. Damage was generally greater in the canopy than in the understorey, in particular for chewing and scraping damage, and the occurrence of mines. There was little difference in herbivory among differently managed forests and the effects of management on damage differed among regions, strata and damage types. Covariates such as wood volume, tree density and plant diversity weakly influenced herbivory, and effects differed between herbivory types. We conclude that despite of the relatively low number of species attacking beech; arthropod herbivory on beech is generally high. We further conclude that responses of herbivory to forest management are multifaceted and environmental factors such as forest structure variables affecting in particular microclimatic conditions are more likely to explain the variability in herbivory among beech forest
Campos-Navarrete, María José; Abdala-Roberts, Luis; Munguía-Rosas, Miguel A.; Parra-Tabla, Víctor
Plant diversity can influence predators and omnivores and such effects may in turn influence herbivores and plants. However, evidence for these ecological feedbacks is rare. We evaluated if the effects of tree species (SD) and genotypic diversity (GD) on the abundance of different guilds of insect herbivores associated with big-leaf mahogany (Swietenia macrophylla) were contingent upon the protective effects of ants tending extra-floral nectaries of this species. This study was conducted within a larger experiment consisting of mahogany monocultures and species polycultures of four species and –within each of these two plot types– mahogany was represented by either one or four maternal families. We selected 24 plots spanning these treatment combinations, 10 mahogany plants/plot, and within each plot experimentally reduced ant abundance on half of the selected plants, and surveyed ant and herbivore abundance. There were positive effects of SD on generalist leaf-chewers and sap-feeders, but for the latter group this effect depended on the ant reduction treatment: SD positively influenced sap-feeders under ambient ant abundance but had no effect when ant abundance was reduced; at the same time, ants had negative effects on sap feeders in monoculture but no effect in polyculture. In contrast, SD did not influence specialist stem-borers or leaf-miners and this effect was not contingent upon ant reduction. Finally, GD did not influence any of the herbivore guilds studied, and such effects did not depend on the ant treatment. Overall, we show that tree species diversity influenced interactions between a focal plant species (mahogany) and ants, and that such effects in turn mediated plant diversity effects on some (sap-feeders) but not all the herbivores guilds studied. Our results suggest that the observed patterns are dependent on the combined effects of herbivore identity, diet breadth, and the source of plant diversity. PMID:26241962
Reidinger, Stefan; Eschen, René; Gange, Alan C.; Finch, Paul; Bezemer, T. Martijn
Arbuscular mycorrhizal fungi (AMF) can affect insect herbivores by changing plant growth and chemistry. However, many factors can influence the symbiotic relationship between plant and fungus, potentially obscuring experimental treatments and ecosystem impacts. In a field experiment, we assessed AMF colonization levels of individual ragwort ( Senecio jacobaea) plants growing in grassland plots that were originally sown with 15 or 4 plant species, or were unsown. We measured the concentrations of carbon, nitrogen and pyrrolizidine alkaloids (PAs), and assessed the presence of aboveground insect herbivores on the sampled plants. Total AMF colonization and colonization by arbuscules was lower in plots sown with 15 species than in plots sown with 4 species and unsown plots. AMF colonization was positively related to the cover of oxeye daisy ( Leucanthemum vulgare) and a positive relationship between colonization by arbuscules and the occurrence of a specialist seed-feeding fly ( Pegohylemyia seneciella) was found. The occurrence of stem-boring, leaf-mining and sap-sucking insects was not affected by AMF colonization. Total PA concentrations were negatively related to colonization levels by vesicles, but did not differ among the sowing treatments. No single factor explained the observed differences in AMF colonization among the sowing treatments or insect herbivore occurrence on S. jacobaea. However, correlations across the treatments suggest that some of the variation was due to the abundance of one plant species, which is known to stimulate AMF colonization of neighbouring plants, while AMF colonization was related to the occurrence of a specialist insect herbivore. Our results thus illustrate that in natural systems, the ecosystem impact of AMF through their influence on the occurrence of specialist insects can be recognised, but they also highlight the confounding effect of neighbouring plant species identity. Hence, our results emphasise the importance of field
Ibañez, Silvina; Rosa, Mariana; Hilal, Mirna; González, Juan A; Prado, Fernando E
Plants of Citrus aurantifolia grown in a greenhouse without solar UV radiation (UVR) were transferred outdoors to evaluate the effect of solar UV-B radiation (UVBR, 280-315 nm) in prior-developed leaves, constituted by apical bud and those fully expanded before being taken outdoors, and post-developed leaves, formed by those expanded outdoors. Results demonstrated that over a 40 d outdoor period leaf chlorophyll content and distribution pattern were different with and without solar UVBR. Chlorophyll a, chlorophyll b and total chlorophyll contents in both treatments were higher in prior-developed leaves than in post-developed ones. However, highest values were observed in prior-developed leaves under solar UVBR, whereas in post-developed leaves an opposite trend was observed. Carotenoids content in prior-developed leaves was higher with solar UVBR, whereas in post-developed leaves there were no significant differences in both with and without solar UVBR. In addition, prior-developed leaves under solar UVBR accumulated flavonoids, but not anthocyanins. Growth parameters (e.g. DW, DW/FW ratio, LMA, plant height, length and width of foliar lamina) did not show significant differences between plants grown with and without solar UVBR. Thus, our results demonstrated that C. aurantifolia leaves exhibited a different sensibility to solar UVBR according to development stage in relation to photosynthetic pigments and UV-B absorbing compounds production. In addition, the solar UVBR was not necessary as inductor of photosynthetic protection mechanisms in a short-time growth period. On the other hand, our results also demonstrated that solar UVBR acted as an effective feeding deterrent against citrus leafminer.
Hebert, Julie B; Scheffer, Sonja J; Hawthorne, David J
Recently diverged taxa often show discordance in genetic divergence among genomic loci, where some loci show strong divergence and others show none at all. Genetic studies alone cannot distinguish among the possible mechanisms but experimental studies on other aspects of divergence may provide guidance in the inference of causes of observed discordances. In this study, we used no-choice mating trials to test for the presence of reproductive isolation between host races of the leaf-mining fly, Phytomyza glabricola on its two holly host species, Ilex coriacea and I. glabra. These trials inform our effort to determine the cause of significant differences in the degree of divergence of nuclear and mitochondrial loci of flies collected from the two host plants. We present evidence of reproductive isolation between host races in a controlled greenhouse setting: significantly more mate pairs consisting of flies from the same host plant species produced offspring than inter-host mate pairs, which produced no offspring. We also tested whether the presence of the natal or non-natal host plant affects reproductive success. Flies collected from I. coriacea were more likely to produce offspring when in the presence of the natal host, whereas the presence or absence of either the natal or non-natal host had no effect on flies collected from I. glabra. The results indicate discordant patterns of nuclear and mitochondrial divergence among host races of P. glabricola are likely due to incomplete lineage sorting, and the host races may be well on their way to becoming biological species.
Camargo, Roberto A; Barbosa, Guilherme O; Possignolo, Isabella Presotto; Peres, Lazaro E P; Lam, Eric; Lima, Joni E; Figueira, Antonio; Marques-Souza, Henrique
RNA interference (RNAi), a gene-silencing mechanism that involves providing double-stranded RNA molecules that match a specific target gene sequence, is now widely used in functional genetic studies. The potential application of RNAi-mediated control of agricultural insect pests has rapidly become evident. The production of transgenic plants expressing dsRNA molecules that target essential insect genes could provide a means of specific gene silencing in larvae that feed on these plants, resulting in larval phenotypes that range from loss of appetite to death. In this report, we show that the tomato leafminer ( Tuta absoluta ), a major threat to commercial tomato production, can be targeted by RNAi. We selected two target genes (Vacuolar ATPase-A and Arginine kinase) based on the RNAi response reported for these genes in other pest species. In view of the lack of an artificial diet for T. absoluta, we used two approaches to deliver dsRNA into tomato leaflets. The first approach was based on the uptake of dsRNA by leaflets and the second was based on "in planta-induced transient gene silencing" (PITGS), a well-established method for silencing plant genes, used here for the first time to deliver in planta-transcribed dsRNA to target insect genes. Tuta absoluta larvae that fed on leaves containing dsRNA of the target genes showed an ∼60% reduction in target gene transcript accumulation, an increase in larval mortality and less leaf damage. We then generated transgenic 'Micro-Tom' tomato plants that expressed hairpin sequences for both genes and observed a reduction in foliar damage by T. absoluta in these plants. Our results demonstrate the feasibility of RNAi as an alternative method for controlling this critical tomato pest.
Valade, R; Kenis, M; Hernandez-Lopez, A; Augustin, S; Mari Mena, N; Magnoux, E; Rougerie, R; Lakatos, F; Roques, A; Lopez-Vaamonde, C
Biological invasions usually start with a small number of founder individuals. These founders are likely to represent a small fraction of the total genetic diversity found in the source population. Our study set out to trace genetically the geographical origin of the horse-chestnut leafminer, Cameraria ohridella, an invasive microlepidopteran whose area of origin is still unkown. Since its discovery in Macedonia 25 years ago, this insect has experienced an explosive westward range expansion, progressively colonizing all of Central and Western Europe. We used cytochrome oxidase I sequences (DNA barcode fragment) and a set of six polymorphic microsatellites to assess the genetic variability of C. ohridella populations, and to test the hypothesis that C. ohridella derives from the southern Balkans (Albania, Macedonia and Greece). Analysis of mtDNA of 486 individuals from 88 localities allowed us to identify 25 geographically structured haplotypes. In addition, 480 individuals from 16 populations from Europe and the southern Balkans were genotyped for 6 polymorphic microsatellite loci. High haplotype diversity and low measures of nucleotide diversities including a significantly negative Tajima's D indicate that C. ohridella has experienced rapid population expansion during its dispersal across Europe. Both mtDNA and microsatellites show a reduction in genetic diversity of C. ohridella populations sampled from artificial habitats (e.g. planted trees in public parks, gardens, along roads in urban or sub-urban areas) across Europe compared with C. ohridella sampled in natural stands of horse-chestnuts in the southern Balkans. These findings suggest that European populations of C. ohridella may indeed derive from the southern Balkans.
Cuthbertson, Andrew G.S.; Mathers, James J.; Blackburn, Lisa F.; Korycinska, Anastasia; Luo, Weiqi; Jacobson, Robert J.; Northing, Phil
Tomato leafminer Tuta absoluta (Meyrick) is a major pest of tomato plants in South America. It was first recorded in the UK in 2009 where it has been subjected to eradication policies. The current work outlines T. absoluta development under various UK glasshouse temperatures. The optimum temperature for Tuta development ranged from 19–23 °C. At 19 °C, there was 52% survival of T. absoluta from egg to adult. As temperature increased (23 °C and above) development time of the moth would appear to decrease. Population development ceases between 7 and 10 °C. Only 17% of eggs hatched at 10 °C but no larvae developed through to adult moths. No eggs hatched when maintained at 7 °C. Under laboratory conditions the total lifespan of the moth was longest (72 days) at 13 °C and shortest (35 days) at both 23 and 25 °C. Development from egg to adult took 58 days at 13 °C; 37 days at 19 °C and 23 days at 25 °C. High mortality of larvae occurred under all temperatures tested. First instar larvae were exposed on the leaf surface for approximately 82 minutes before fully tunnelling into the leaf. Adult longevity was longest at 10 °C with moths living for 40 days and shortest at 19 °C where they survived for 16 days. Generally more males than females were produced. The potential of Tuta absoluta to establish populations within UK protected horticulture is discussed. PMID:26464384
Zhang, Sufang; Wei, Jianing; Kang, Le
Background Exposure of plants to herbivore-induced plant volatiles (HIPVs) alters their resistance to herbivores. However, the whole-genome transcriptional responses of treated plants remain unknown, and the signal pathways that produce HIPVs are also unclear. Methodology/Principal Findings Time course patterns of the gene expression of Arabidopsis thaliana exposed to Lima bean volatiles were examined using Affymetrix ATH1 genome arrays. Results showed that A. thaliana received and responded to leafminer-induced volatiles from Lima beans through up-regulation of genes related to the ethylene (ET) and jasmonic acid pathways. Time course analysis revealed strong and partly qualitative differences in the responses between exposure at 24 and that at 48 h. Further experiments using either A. thaliana ET mutant ein2-1 or A. thaliana jasmonic acid mutant coi1-2 indicated that both pathways are involved in the volatile response process but that the ET pathway is indispensable for detecting volatiles. Moreover, transcriptional comparisons showed that plant responses to larval feeding do not merely magnify the volatile response process. Finally, (Z)-3-hexen-ol, ocimene, (3E)-4,8-dimethyl-1,3,7-nonatriene, and (3E,7E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene triggered responses in A. thaliana similar to those induced by the entire suite of Lima bean volatiles after 24 and 48 h. Conclusions/Significance This study shows that the transcriptional responses of plants to HIPVs become stronger as treatment time increases and that ET signals are critical during this process. PMID:22558246
Larbat, R; Adamowicz, S; Robin, C; Han, P; Desneux, N; Le Bot, J
Plant-insect interactions are strongly modified by environmental factors. This study evaluates the influence of nitrogen fertilisation on the tomato (Solanum lycopersicum L.) cv. Santa clara and the leafminer (Tuta absoluta (Meyrick), Lepidoptera: Gelechiidae). Greenhouse-grown tomato plants were fed hydroponically on a complete nutrient solution containing either a high nitrogen concentration (HN) sustaining maximum growth or a low nitrogen concentration (LN) limiting plant growth. Insect-free plants were compared with plants attacked by T. absoluta. Seven and 14 days after artificial oviposition leading to efficacious hatching and larvae development, we measured total carbon, nitrogen and soluble protein as well as defence compounds (phenolics, glycoalkaloids, polyphenol oxidase activity) in the HN versus LN plants. Only in the HN treatment did T. absoluta infestation slightly impair leaf growth and induce polyphenol oxidase (PPO) activity in the foliage. Neither the concentration of phenolic compounds and proteins nor the distribution of nitrogen within the plant was affected by T. absoluta infestation. In contrast, LN nutrition impaired T. absoluta-induced PPO activity. It decreased protein and total nitrogen concentration of plant organs and enhanced the accumulation of constitutive phenolics and tomatine. Moreover, LN nutrition impaired T. absoluta development by notably decreasing pupal weight and lengthening the development period from egg to adult. Adjusting the level of nitrogen nutrition may thus be a means of altering the life cycle of T. absoluta. This study provides a comprehensive dataset concerning interrelated responses of tomato plants and T. absoluta to nitrogen nutrition.
Bezemer, T Martijn; Harvey, Jeffrey A; Kowalchuk, George A; Korpershoek, Hanna; van der Putten, Wim H
To elucidate the factors that affect the performance of plants in their natural environment, it is essential to study interactions with other neighboring plants, as well as with above- and belowground higher trophic organisms. We used a long-term field experiment to study how local plant community diversity influenced colonization by the biennial composite Senecio jacobaea in its native range in The Netherlands in Europe. We tested the effect of sowing later-succession plant species (0, 4, or 15 species) on plant succession and S. jacobaea performance. Over a period of eight years, the percent cover of S. jacobaea was relatively low in communities sown with 15 or 4 later-succession plant species compared to plots that were not sown, but that were colonized naturally. However, after four years of high abundance, the density of S. jacobaea in unsown plots started to decline, and the size of the individual plants was smaller than in the plots sown with 15 or 4 plant species. In the unsown plots, densities of aboveground leaf-mining, flower-feeding, and stem-boring insects on S. jacobaea plants were lower than on plants in sown plots, and there was a strong positive relationship between plant size and levels of herbivory. In a greenhouse experiment, we grew S. jacobaea in sterilized soil inoculated with soil from the different sowing treatments of the field experiment. Biomass production was lower when S. jacobaea test plants were grown in soil from the unsown plots than in soil from the sown plots (4 or 15 species). Molecular analysis of the fungal and bacterial communities revealed that the composition of fungal communities in unsown plots differed significantly from those in sown plots, suggesting that soil fungi could have been involved in the relative growth reduction of S. jacobaea in the greenhouse bioassay. Our results show that, in its native habitat, the abundance of S. jacobaea depends on the initial composition of the plant community and that, on a scale of