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Sample records for intake device aphid

  1. Design and implementation of a medication reconciliation kiosk: the Automated Patient History Intake Device (APHID).

    PubMed

    Lesselroth, Blake J; Felder, Robert S; Adams, Shawn M; Cauthers, Phillip D; Dorr, David A; Wong, Gordon J; Douglas, David M

    2009-01-01

    Errors associated with medication documentation account for a substantial fraction of preventable medical errors. Hence, the Joint Commission has called for the adoption of reconciliation strategies at all United States healthcare institutions. Although studies suggest that reconciliation tools can reduce errors, it remains unclear how best to implement systems and processes that are reliable and sensitive to clinical workflow. The authors designed a primary care process that supported reconciliation without compromising clinic efficiency. This manuscript describes the design and implementation of Automated Patient History Intake Device (APHID): ambulatory check-in kiosks that allow patients to review the names, dosage, frequency, and pictures of their medications before their appointment. Medication lists are retrieved from the electronic health record and patient updates are captured and reviewed by providers during the clinic session. Results from the roll-in phase indicate the device is easy for patients to use and integrates well with clinic workflow.

  2. Design and Implementation of a Medication Reconciliation Kiosk: the Automated Patient History Intake Device (APHID)

    PubMed Central

    Lesselroth, Blake J.; Felder, Robert S.; Adams, Shawn M.; Cauthers, Phillip D.; Dorr, David A.; Wong, Gordon J.; Douglas, David M.

    2009-01-01

    Errors associated with medication documentation account for a substantial fraction of preventable medical errors. Hence, the Joint Commission has called for the adoption of reconciliation strategies at all United States healthcare institutions. Although studies suggest that reconciliation tools can reduce errors, it remains unclear how best to implement systems and processes that are reliable and sensitive to clinical workflow. The authors designed a primary care process that supported reconciliation without compromising clinic efficiency. This manuscript describes the design and implementation of Automated Patient History Intake Device (APHID): ambulatory check-in kiosks that allow patients to review the names, dosage, frequency, and pictures of their medications before their appointment. Medication lists are retrieved from the electronic health record and patient updates are captured and reviewed by providers during the clinic session. Results from the roll-in phase indicate the device is easy for patients to use and integrates well with clinic workflow. PMID:19261949

  3. Intake device of an internal combustion engine

    SciTech Connect

    Okumura, T.; Nakanishi, K.; Matsushita, S.

    1986-05-06

    An intake device of an internal combustion engine is described which consists of: an intake port; a separating wall arranged in the intake port and dividing an interior of the intake port into a straight port and a helical-shaped port which has a helical portion having a helix terminating portion; a control valve arranged in the straight port; a projection formed on a side wall of the separating wall, which defines the straight port, at a position downstream of the control valve, the projection having a tip face directed upstream of the intake port; a bypass passage formed in the separating wall and having an inlet opening and an outlet opening which is open to the helix terminating portion, the inlet opening being formed on the tip face; and an actuator for actuating the control valve in response to an engine load to close the control valve when the engine load is lower than a predetermined load and to open the control valve when the engine load is higher than the predetermined load.

  4. Aphid pheromones.

    PubMed

    Dewhirst, Sarah Y; Pickett, John A; Hardie, Jim

    2010-01-01

    Aphids are the main insect pests of agricultural crops in temperate regions causing major economic losses. Although broad-spectrum insecticides are available for control, alternative and more targeted methods are needed due to insecticide resistance and increasing environmental pressures. An alternative control method for aphids is to exploit their pheromones, which have been extensively studied in recent years. For example, aphids release alarm pheromones in response to natural enemy attack and these could be used to deter aphids from the crops. Sex pheromones have also been identified which could be used to interfere males locating conspecific females (oviparae), as well as for manipulating natural enemies. Several hypotheses relating to how species integrity is maintained via the aphid sex pheromone have been proposed. The composition and behavioral activity of these pheromones, and how their use could be implemented in integrated pest management systems to control aphids, is discussed. Copyright © 2010 Elsevier Inc. All rights reserved.

  5. Aphids as crop pests

    USDA-ARS?s Scientific Manuscript database

    This book of contributed articles by 68 leading aphid researchers is the most complete gathering of current aphid knowledge since the three volume work entitled “Aphids: Their Biology, Natural Enemies and Control” published in 1987 through 1989 (Minks and Harrewijn, 1987). The new book offers a cons...

  6. A Novel Wearable Device for Food Intake and Physical Activity Recognition

    PubMed Central

    Farooq, Muhammad; Sazonov, Edward

    2016-01-01

    Presence of speech and motion artifacts has been shown to impact the performance of wearable sensor systems used for automatic detection of food intake. This work presents a novel wearable device which can detect food intake even when the user is physically active and/or talking. The device consists of a piezoelectric strain sensor placed on the temporalis muscle, an accelerometer, and a data acquisition module connected to the temple of eyeglasses. Data from 10 participants was collected while they performed activities including quiet sitting, talking, eating while sitting, eating while walking, and walking. Piezoelectric strain sensor and accelerometer signals were divided into non-overlapping epochs of 3 s; four features were computed for each signal. To differentiate between eating and not eating, as well as between sedentary postures and physical activity, two multiclass classification approaches are presented. The first approach used a single classifier with sensor fusion and the second approach used two-stage classification. The best results were achieved when two separate linear support vector machine (SVM) classifiers were trained for food intake and activity detection, and their results were combined using a decision tree (two-stage classification) to determine the final class. This approach resulted in an average F1-score of 99.85% and area under the curve (AUC) of 0.99 for multiclass classification. With its ability to differentiate between food intake and activity level, this device may potentially be used for tracking both energy intake and energy expenditure. PMID:27409622

  7. Feeding Experimentation Device (FED): Construction and Validation of an Open-source Device for Measuring Food Intake in Rodents.

    PubMed

    Nguyen, Katrina P; Ali, Mohamed A; O'Neal, Timothy J; Szczot, Ilona; Licholai, Julia A; Kravitz, Alexxai V

    2017-02-21

    Food intake measurements are essential for many research studies. Here, we provide a detailed description of a novel solution for measuring food intake in mice: the Feeding Experimentation Device (FED). FED is an open-source system that was designed to facilitate flexibility in food intake studies. Due to its compact and battery powered design, FED can be placed within standard home cages or other experimental equipment. Food intake measurements can also be synchronized with other equipment in real-time via FED's transistor-transistor logic (TTL) digital output, or in post-acquisition processing as FED timestamps every event with a real-time clock. When in use, a food pellet sits within FED's food well where it is monitored via an infrared beam. When the pellet is removed by the mouse, FED logs the timestamp onto its internal secure digital (SD) card and dispenses another pellet. FED can run for up to 5 days before it is necessary to charge the battery and refill the pellet hopper, minimizing human interference in data collection. Assembly of FED requires minimal engineering background, and off-the-shelf materials and electronics were prioritized in its construction. We also provide scripts for analysis of food intake and meal patterns. Finally, FED is open-source and all design and construction files are online, to facilitate modifications and improvements by other researchers.

  8. The semiochemistry of aphids.

    PubMed

    Pickett, John A; Allemannb, Rudolf K; Birketta, Michael A

    2013-10-11

    Chemical signalling between aphids (small insects that suck plant sap) formating and avoidance of antagonistic organisms, and between aphids and plants for location of hosts or avoidance of unsuitable plants, employs minute levels of small lipophilic molecules (SLMs), termed "semiochemicals". These semiochemicals, which include sex and alarm pheromones, although often involving relatively simple volatile compounds to allow aerial transmission, convey highly accurate information, either through the uniqueness of their chemical structure or by acting together in characteristic mixtures. In addition, by chemical instability, they do not remain in the environment after their essential signalling role has occurred. Aphids, as a consequence of direct feeding or virus transmission, are major pests of agriculture and horticulture. Aphid semiochemicals present novel opportunities for management of pest populations, but problems of synthesis costs and delivery need to be overcome. Genes for associated enzymes in aphids and plants offer solutions, either for production and subsequent deployment in agriculture, or for direct biosynthesis by crop plants as a new generation of genetically modified organisms (GMOs). These approaches are currently under active investigation. Semiochemicals released from plants during aphid feeding can also "switch on" defence chemistry-related genes in intact plants under field conditions, and the gene promoter sequences involved could be used to produce novel types of sentinel plants. The molecular recognition mechanisms employed in aphid olfactory systems are being investigated to provide potential tools for recognition of SLMs, and the acceptance of substrate analogues is explored with enzymes synthesising aphid semiochemicals in an attempt to provide more active or stable structural analogues.

  9. Arabidopsis thaliana—Aphid Interaction

    PubMed Central

    Louis, Joe; Singh, Vijay; Shah, Jyoti

    2012-01-01

    Aphids are important pests of plants that use their stylets to tap into the sieve elements to consume phloem sap. Besides the removal of photosynthates, aphid infestation also alters source-sink patterns. Most aphids also vector viral diseases. In this chapter, we will summarize on recent significant findings in plant-aphid interaction, and how studies involving Arabidopsis thaliana and Myzus persicae (Sülzer), more commonly known as the green peach aphid (GPA), are beginning to provide important insights into the molecular basis of plant defense and susceptibility to aphids. The recent demonstration that expression of dsRNA in Arabidopsis can be used to silence expression of genes in GPA has further expanded the utility of Arabidopsis for evaluating the contribution of the aphid genome-encoded proteins to this interaction. PMID:22666177

  10. Ants defend aphids against lethal disease.

    PubMed

    Nielsen, Charlotte; Agrawal, Anurag A; Hajek, Ann E

    2010-04-23

    Social insects defend their own colonies and some species also protect their mutualist partners. In mutualisms with aphids, ants typically feed on honeydew produced by aphids and, in turn guard and shelter aphid colonies from insect natural enemies. Here we report that Formica podzolica ants tending milkweed aphids, Aphis asclepiadis, protect aphid colonies from lethal fungal infections caused by an obligate aphid pathogen, Pandora neoaphidis. In field experiments, bodies of fungal-killed aphids were quickly removed from ant-tended aphid colonies. Ant workers were also able to detect infective conidia on the cuticle of living aphids and responded by either removing or grooming these aphids. Our results extend the long-standing view of ants as mutualists and protectors of aphids by demonstrating focused sanitizing and quarantining behaviour that may lead to reduced disease transmission in aphid colonies.

  11. Ants defend aphids against lethal disease

    PubMed Central

    Nielsen, Charlotte; Agrawal, Anurag A.; Hajek, Ann E.

    2010-01-01

    Social insects defend their own colonies and some species also protect their mutualist partners. In mutualisms with aphids, ants typically feed on honeydew produced by aphids and, in turn guard and shelter aphid colonies from insect natural enemies. Here we report that Formica podzolica ants tending milkweed aphids, Aphis asclepiadis, protect aphid colonies from lethal fungal infections caused by an obligate aphid pathogen, Pandora neoaphidis. In field experiments, bodies of fungal-killed aphids were quickly removed from ant-tended aphid colonies. Ant workers were also able to detect infective conidia on the cuticle of living aphids and responded by either removing or grooming these aphids. Our results extend the long-standing view of ants as mutualists and protectors of aphids by demonstrating focused sanitizing and quarantining behaviour that may lead to reduced disease transmission in aphid colonies. PMID:19923138

  12. Deriving a provisional tolerable intake for intravenous exposure to silver nanoparticles released from medical devices.

    PubMed

    Savery, Laura C; Viñas, René; Nagy, Amber M; Pradeep, Prachi; Merrill, Stephen J; Hood, Alan M; Malghan, Subhas G; Goering, Peter L; Brown, Ronald P

    2017-04-01

    Silver nanoparticles (AgNP) are incorporated into medical devices for their anti-microbial characteristics. The potential exposure and toxicity of AgNPs is unknown due to varying physicochemical particle properties and lack of toxicological data. The aim of this safety assessment is to derive a provisional tolerable intake (pTI) value for AgNPs released from blood-contacting medical devices. A literature review of in vivo studies investigating critical health effects induced from intravenous (i. v.) exposure to AgNPs was evaluated by the Annapolis Accords principles and Toxicological Data Reliability Assessment Tool (ToxRTool). The point of departure (POD) was based on an i. v. 28-day repeated AgNP (20 nm) dose toxicity study reporting an increase in relative spleen weight in rats with a 5% lower confidence bound of the benchmark dose (BMDL05) of 0.14 mg/kg bw/day. The POD was extrapolated to humans by a modifying factor of 1,000 to account for intraspecies variability, interspecies differences and lack of long-term toxicity data. The pTI for long-term i. v. exposure to 20 nm AgNPs released from blood-contacting medical devices was 0.14 μg/kg bw/day. This pTI may not be appropriate for nanoparticles of other physicochemical properties or routes of administration. The methodology is appropriate for deriving pTIs for nanoparticles in general.

  13. Compatible plant-aphid interactions: how aphids manipulate plant responses.

    PubMed

    Giordanengo, Philippe; Brunissen, Laurence; Rusterucci, Christine; Vincent, Charles; van Bel, Aart; Dinant, Sylvie; Girousse, Christine; Faucher, Mireille; Bonnemain, Jean-Louis

    2010-01-01

    To access phloem sap, aphids have developed a furtive strategy, their stylets progressing towards sieve tubes mainly through the apoplasmic compartment. Aphid feeding requires that they overcome a number of plant responses, ranging from sieve tube occlusion and activation of phytohormone-signalling pathways to expression of anti-insect molecules. In addition to bypassing plant defences, aphids have been shown to affect plant primary metabolism, which could be a strategy to improve phloem sap composition in nutrients required for their growth. During compatible interactions, leading to successful feeding and reproduction, aphids cause alterations in their host plant, including morphological changes, modified resource allocation and various local as well as systemic symptoms. Repeated salivary secretions injected from the first probe in the epidermal tissue up to ingestion of sieve-tube sap may play a crucial role in the compatibility between the aphid and the plant.

  14. Bird Cherry-Oat Aphid

    USDA-ARS?s Scientific Manuscript database

    • The bird cherry-oat aphid (Rhopalosiphum padi) is an important vector of barley yellow dwarf viruses that affect wheat and other small-grain crops, but the aphid may also cause direct feeding damage to wheat. • Various plant-resistance modalities and natural enemies are not equally applicable in s...

  15. Volatile communication in plant-aphid interactions.

    PubMed

    de Vos, Martin; Jander, Georg

    2010-08-01

    Volatile communication plays an important role in mediating the interactions between plants, aphids, and other organisms in the environment. In response to aphid infestation, many plants initiate indirect defenses through the release of volatiles that attract ladybugs, parasitoid wasps, and other aphid-consuming predators. Aphid-induced volatile release in the model plant Arabidopsis thaliana requires the jasmonate signaling pathway. Volatile release is also induced by infection with aphid-transmitted viruses. Consistent with mathematical models of optimal transmission, viruses that are acquired rapidly by aphids induce volatile release to attract migratory aphids, but discourage long-term aphid feeding. Although the ecology of these interactions is well-studied, further research is needed to identify the molecular basis of aphid-induced and virus-induced changes in plant volatile release.

  16. Evaluation of a depth proportional intake device for automatic pumping samplers

    Treesearch

    Rand E. Eads; Robert B. Thomas

    1983-01-01

    Abstract - A depth proportional intake boom for portable pumping samplers was used to collect suspended sediment samples in two coastal streams for three winters. The boom pivots on the stream bed while a float on the downstream end allows debris to depress the boom and pass without becoming trapped. This equipment modifies point sampling by maintaining the intake...

  17. Aphids capable of fine resolution landing

    USDA-ARS?s Scientific Manuscript database

    Aphids vector many devastating plant viruses, including the non-persistent papaya ringspot virus (PRSV), which reduces yield in both cucurbits and papaya. It has been demonstrated that some aphids are more attracted to colors symptomatic of virus infection, especially yellow. However, alate aphids a...

  18. Do aphids actively search for ant partners?

    PubMed

    Fischer, Christophe Y; Vanderplanck, Maryse; Lognay, Georges C; Detrain, Claire; Verheggen, François J

    2015-04-01

    The aphid-ant mutualistic relationships are not necessarily obligate for neither partners but evidence is that such interactions provide them strong advantages in terms of global fitness. While it is largely assumed that ants actively search for their mutualistic partners namely using volatile cues; whether winged aphids (i.e., aphids' most mobile form) are able to select ant-frequented areas had not been investigated so far. Ant-frequented sites would indeed offer several advantages for these aphids including a lower predation pressure through ant presence and enhanced chances of establishing mutuaslistic interactions with neighbor ant colonies. In the field, aphid colonies are often observed in higher densities around ant nests, which is probably linked to a better survival ensured by ants' services. Nevertheless, this could also result from a preferential establishment of winged aphids in ant-frequented areas. We tested this last hypothesis through different ethological assays and show that the facultative myrmecophilous black bean aphid, Aphis fabae L., does not orientate its search for a host plant preferentially toward ant-frequented plants. However, our results suggest that ants reduce the number of winged aphids leaving the newly colonized plant. Thus, ants involved in facultative myrmecophilous interactions with aphids appear to contribute to structure aphid populations in the field by ensuring a better establishment and survival of newly established colonies rather than by inducing a deliberate plant selection by aphid partners based on the proximity of ant colonies.

  19. Soybean aphids making their summer appearance early

    USDA-ARS?s Scientific Manuscript database

    Two small, soft-bodied insects have begun showing up in South Dakota soybean. One is the soybean aphid, and the other is a mealybug. Soybean aphids are yellow to yellow/green and are usually found feeding on the underside of leaves. Incidence of soybean aphid has been a bit higher than typical fo...

  20. Do aphid carcasses on the backs of larvae of green lacewing work as chemical mimicry against aphid-tending ants?

    PubMed

    Hayashi, Masayuki; Choh, Yasuyuki; Nakamuta, Kiyoshi; Nomura, Masashi

    2014-06-01

    Ants attack and exclude natural enemies of aphids in ant-aphid mutualisms. However, larvae of the green lacewing, Mallada desjardinsi, prey on the cowpea aphid, Aphis craccivora, without exclusion by aphid-tending ants. Lacewing larvae are protected from ants by carrying aphid carcasses on their backs. Here, we tested whether cuticular hydrocarbons (CHCs) of aphid carcasses affected the aggressiveness of aphid-tending ants. Aphid carcasses were washed with n-hexane to remove lipids. Lacewing larvae with washed aphid carcasses were attacked by aphid-tending ants more frequently than those with untreated aphid carcasses. We measured the aggressiveness of aphid-tending ants to lacewing larvae that were either carrying a piece of cotton wool (a dummy aphid carcass) treated with CHCs from aphids or lacewing larvae, or carrying aphid carcasses. The rates of attack by ants on lacewing larvae carrying CHCs of aphids or aphid carcasses were lower than that of attack on lacewing larvae with conspecific CHCs. Chemical analysis by gas chromatography/mass spectrometry showed similarity of CHCs between aphids and aphid carcasses. These results suggest that aphid carcasses on the backs of lacewing larvae function via chemical camouflage to limit attacks by aphid-tending ants.

  1. Efficacy of Chemical Mimicry by Aphid Predators Depends on Aphid-Learning by Ants.

    PubMed

    Hayashi, Masayuki; Nomura, Masashi; Nakamuta, Kiyoshi

    2016-03-01

    Chemical mimicry is an effective strategy when signal receivers recognize and discriminate models by relying on chemical cues. Some aphid enemies mimic the cuticular chemicals of aphids through various means thus avoiding detection and attack by aphid-tending ants. However, because ants have been reported to learn the chemical signatures of aphids in order to distinguish the aphids, the efficacy of chemical mimicry is predicted to depend on the experience of the ants that had tended aphids. The present study tested this hypothesis using two predator species: larvae of the green lacewing Mallada desjardinsi, and larvae of the ladybeetle Scymnus posticalis. Lacewing larvae carry the carcasses of aphids on which they have preyed upon their backs, and these function via chemical camouflage to reduce the aggressiveness of aphid-tending ants toward the larvae. Ladybeetle larvae reportedly produce a covering of wax structures, and their chemicals appear to attenuate ant aggression. We examined whether the behavior of the ant Tetramorium tsushimae toward these predators changed depending on their aphid-tending experience. Ants moderated their aggressiveness toward both predators when they had previously tended aphids, indicating that chemical mimicry by both aphid predators is dependent on previous experience of the ants in tending aphids. Chemical mimicry by the predators of ant-tended aphids is therefore considered to exploit learning-dependent aphid recognition systems of ants.

  2. Quantitation and localization of pospiviroids in aphids.

    PubMed

    Van Bogaert, N; De Jonghe, K; Van Damme, E J M; Maes, M; Smagghe, G

    2015-01-01

    In this paper, the potential role of aphids in viroid transmission was explored. Apterous aphids were fed on pospiviroid-infected plants and viroid targets in the aphids were consequently quantified through RT-qPCR and localized within the aphid body using fluorescence in situ hybridization (FISH). Based on the analytical sensitivity test, the limit of detection (LOD) was estimated at 1.69×10(6) viroid copies per individual aphid body. To localize the viroids in the aphids, a pospiviroid-generic Cy5-labelled probe was used and the fluorescent signal was determined by confocal microscopy. Viroids were clearly observed in the aphid's stylet and stomach, but not in the embryos. Viroids were detected in 29% of the aphids after a 24h feeding period, which suggests only a partial and low concentration viroid uptake by the aphid population including viroid concentrations under the LOD. However, these results show that viroids can be ingested by aphids while feeding on infected plants, thus potentially increasing the transmission risk. The combination of FISH and RT-qPCR provides reliable and fast localization and quantitation of viroid targets in individual aphids and thus constitutes a valuable tool in future epidemiological research.

  3. Pandora neoaphidis transmission and aphid foraging behaviour.

    PubMed

    Baverstock, J; Alderson, P G; Pell, J K

    2005-09-01

    Pandora neoaphidis is an aphid-specific entomopathogen that produces infective conidia. As aphid movement increases, so does the likelihood of contact with conidia. Volatile distress signals released in response to aphid infestation as an indirect defence against herbivory may affect aphid foraging and, therefore, the fungus-aphid interaction. In this study, two different methods were used to investigate the effect of plant volatiles and P. neoaphidis-sporulating cadavers on (1) the colonisation of Vicia faba plants by Acyrthosiphon pisum and (2) P. neoaphidis transmission. This study indicates that A. pisum does not avoid bean plants containing P. neoaphidis and that transmission of conidia occurs during plant colonisation and, to a lesser extent, during in situ feeding. Although significantly more aphids were recovered from damaged plants compared to undamaged plants, the likelihood of infection was not affected by previous infestation by aphids.

  4. Exotic aphid control with pathogens

    USDA-ARS?s Scientific Manuscript database

    Exotic aphids are invading ecosystems worldwide. The principal factors favoring establishment of these pests are their small size, parthenogenetic reproduction, short generation time, ability for long distance dispersal as winged morphs, and explosive population dynamics. In the past, attention to i...

  5. SOYBEAN.APHID.LH.2009

    USDA-ARS?s Scientific Manuscript database

    Expression of soybean aphid (SA) resistance was characterized among 496 soybean lines in a twice-replicated field-plot test at the Eastern South Dakota Soil and Water Research Farm near Brookings, SD, in 2009. Natural infestations of SA occurred but were supplemented by placing individual stems of ...

  6. SOYBEAN.APHID.SD.2017

    USDA-ARS?s Scientific Manuscript database

    Infestations by soybean aphid (SA) can reduce soybean yield. Thus, SA-resistant soybean may be useful in reducing infestations and limiting yield loss. Expression of resistance was characterized among 746 soybean accessions in 56 growth chamber tests at the North Central Agricultural Research Labo...

  7. Plant immunity in plant–aphid interactions

    PubMed Central

    Jaouannet, Maëlle; Rodriguez, Patricia A.; Lenoir, Camille J. G.; MacLeod, Ruari; Escudero-Martinez, Carmen; Bos, Jorunn I.B.

    2014-01-01

    Aphids are economically important pests that cause extensive feeding damage and transmit viruses. While some species have a broad host range and cause damage to a variety of crops, others are restricted to only closely related plant species. While probing and feeding aphids secrete saliva, containing effectors, into their hosts to manipulate host cell processes and promote infestation. Aphid effector discovery studies pointed out parallels between infection and infestation strategies of plant pathogens and aphids. Interestingly, resistance to some aphid species is known to involve plant resistance proteins with a typical NB-LRR domain structure. Whether these resistance proteins indeed recognize aphid effectors to trigger ETI remains to be elucidated. In addition, it was recently shown that unknown aphid derived elicitors can initiate reactive oxygen species (ROS) production and callose deposition and that these responses were dependent on BAK1 (BRASSINOSTERIOD INSENSITIVE 1-ASSOCIATED RECEPTOR KINASE 1) which is a key component of the plant immune system. In addition, BAK-1 contributes to non-host resistance to aphids pointing to another parallel between plant-pathogen and – aphid interactions. Understanding the role of plant immunity and non-host resistance to aphids is essential to generate durable and sustainable aphid control strategies. Although insect behavior plays a role in host selection and non-host resistance, an important observation is that aphids interact with non-host plants by probing the leaf surface, but are unable to feed or establish colonization. Therefore, we hypothesize that aphids interact with non-host plants at the molecular level, but are potentially not successful in suppressing plant defenses and/or releasing nutrients. PMID:25520727

  8. Categorizing sugarcane cultivar resistance to the sugarcane aphid and yellow sugarcane aphid (Hemiptera: Aphididae)

    USDA-ARS?s Scientific Manuscript database

    Sugarcane in the U.S. is chiefly colonized by two aphid species, the sugarcane aphid, Melanaphis sacchari, and the yellow sugarcane aphid, Sipha flava, which vector economically important viruses of the crop. Greenhouse experiments were conducted to categorize commercial sugarcane cultivars for the...

  9. Categorizing Sugarcane Cultivar Resistance to the Sugarcane Aphid and Yellow Sugarcane Aphid (Hemiptera: Aphidae)

    USDA-ARS?s Scientific Manuscript database

    Sugarcane in Louisiana is colonized by two aphid species, the sugarcane aphid, Melanaphis sacchari (Zehntner), and the yellow sugarcane aphid, Sipha flava (Forbes). The main problem associated with M. sacchari is transmission of sugarcane yellow leaf virus, a disease that has been added to certifica...

  10. Aphid-proof plants: biotechnology-based approaches for aphid control.

    PubMed

    Will, Torsten; Vilcinskas, Andreas

    2013-01-01

    Aphids are economically significant agricultural pests that are responsible for large yield losses in many different crops. Because the use of insecticides is restricted in the context of integrated pest management and aphids develop resistance against them rapidly, new biotechnology-based approaches are required for aphid control. These approaches focus on the development of genetically modified aphid-resistant plants that express protease inhibitors, dsRNA, antimicrobial peptides, or repellents, thus addressing different levels of aphid-plant interactions. However, a common goal is to disturb host plant acceptance by aphids and to disrupt their ability to take nutrition from plants. The defense agents negatively affect different fitness-associated parameters such as growth, reproduction, and survival, which therefore reduce the impact of infestations. The results from several different studies suggest that biotechnology-based approaches offer a promising strategy for aphid control.

  11. AphidBase: A centralized bioinformatic resource for annotation of the pea aphid genome

    PubMed Central

    Legeai, Fabrice; Shigenobu, Shuji; Gauthier, Jean-Pierre; Colbourne, John; Rispe, Claude; Collin, Olivier; Richards, Stephen; Wilson, Alex C. C.; Tagu, Denis

    2015-01-01

    AphidBase is a centralized bioinformatic resource that was developed to facilitate community annotation of the pea aphid genome by the International Aphid Genomics Consortium (IAGC). The AphidBase Information System designed to organize and distribute genomic data and annotations for a large international community was constructed using open source software tools from the Generic Model Organism Database (GMOD). The system includes Apollo and GBrowse utilities as well as a wiki, blast search capabilities and a full text search engine. AphidBase strongly supported community cooperation and coordination in the curation of gene models during community annotation of the pea aphid genome. AphidBase can be accessed at http://www.aphidbase.com. PMID:20482635

  12. A functional genomics approach identifies candidate effectors from the aphid species Myzus persicae (green peach aphid).

    PubMed

    Bos, Jorunn I B; Prince, David; Pitino, Marco; Maffei, Massimo E; Win, Joe; Hogenhout, Saskia A

    2010-11-18

    Aphids are amongst the most devastating sap-feeding insects of plants. Like most plant parasites, aphids require intimate associations with their host plants to gain access to nutrients. Aphid feeding induces responses such as clogging of phloem sieve elements and callose formation, which are suppressed by unknown molecules, probably proteins, in aphid saliva. Therefore, it is likely that aphids, like plant pathogens, deliver proteins (effectors) inside their hosts to modulate host cell processes, suppress plant defenses, and promote infestation. We exploited publicly available aphid salivary gland expressed sequence tags (ESTs) to apply a functional genomics approach for identification of candidate effectors from Myzus persicae (green peach aphid), based on common features of plant pathogen effectors. A total of 48 effector candidates were identified, cloned, and subjected to transient overexpression in Nicotiana benthamiana to assay for elicitation of a phenotype, suppression of the Pathogen-Associated Molecular Pattern (PAMP)-mediated oxidative burst, and effects on aphid reproductive performance. We identified one candidate effector, Mp10, which specifically induced chlorosis and local cell death in N. benthamiana and conferred avirulence to recombinant Potato virus X (PVX) expressing Mp10, PVX-Mp10, in N. tabacum, indicating that this protein may trigger plant defenses. The ubiquitin-ligase associated protein SGT1 was required for the Mp10-mediated chlorosis response in N. benthamiana. Mp10 also suppressed the oxidative burst induced by flg22, but not by chitin. Aphid fecundity assays revealed that in planta overexpression of Mp10 and Mp42 reduced aphid fecundity, whereas another effector candidate, MpC002, enhanced aphid fecundity. Thus, these results suggest that, although Mp10 suppresses flg22-triggered immunity, it triggers a defense response, resulting in an overall decrease in aphid performance in the fecundity assays. Overall, we identified aphid

  13. Spruce aphid (Elatobium abietinum Walker) (Hemiptera: Aphididae) [Chapter XXIV

    Treesearch

    Ann M. Lynch

    2014-01-01

    Elatobium abietinum Walker is a spruce-feeding aphid that in Europe is referred to as the green spruce aphid (Day et al., 1998a) (Fig. 1). However, in North America E. abietinum is known simply as the spruce aphid, while the common name "green spruce aphid" refers to a different species, Cinara fornacula Hottes (Hemiptera: Aphididae) (http://www.entsoc.org/...

  14. Specialization of bacterial endosymbionts that protect aphids from parasitoids

    USDA-ARS?s Scientific Manuscript database

    Infection by the bacterial endosymbiont HAMILTONELLA DEFENSA is capable of protecting the pea aphid from parasitism by APHIDIUS ERVI and the black bean aphid from parasitism by LYSIPHLEBUS FABARUM. Here we investigate protection of a third aphid species, the cowpea aphid, APHIS CRACCIVORA, from 4 p...

  15. Developing Metrics for Managing Soybean Aphids

    USDA-ARS?s Scientific Manuscript database

    Stage-specific economic injury levels form the basis of integrated pest management for soybean aphid (Aphis glycines Matsumura) in soybean (Glycine max L.). Experimental objectives were to develop a procedure for calculating economic injury levels of the soybean aphid specific to the R2 (full bloom...

  16. Management of Sugarcane Aphid in Sorghum

    ERIC Educational Resources Information Center

    Zerger, Sarah

    2017-01-01

    Sugarcane aphids are becoming a more prevalent pest in sorghum in the United States, especially in the south and are making their way north. There are many management practices that can be used on sugarcane aphids, the most important being scouting and maintaining populations. The most common mistake once a pest has been found is to immediately…

  17. Transparency Master: The Annual Aphid Cycle.

    ERIC Educational Resources Information Center

    Sessions, Mary Lynne

    1983-01-01

    Aphids, often referred to as plant lice, can be found in great numbers on stems, leaves, and flowers of many plants. In many cases these organisms are potentially harmful to their plant hosts. Provided is a description of the annual life cycle of the aphid and an accompanying transparency master. (Author/JN)

  18. Transparency Master: The Annual Aphid Cycle.

    ERIC Educational Resources Information Center

    Sessions, Mary Lynne

    1983-01-01

    Aphids, often referred to as plant lice, can be found in great numbers on stems, leaves, and flowers of many plants. In many cases these organisms are potentially harmful to their plant hosts. Provided is a description of the annual life cycle of the aphid and an accompanying transparency master. (Author/JN)

  19. A glasses-type wearable device for monitoring the patterns of food intake and facial activity

    NASA Astrophysics Data System (ADS)

    Chung, Jungman; Chung, Jungmin; Oh, Wonjun; Yoo, Yongkyu; Lee, Won Gu; Bang, Hyunwoo

    2017-01-01

    Here we present a new method for automatic and objective monitoring of ingestive behaviors in comparison with other facial activities through load cells embedded in a pair of glasses, named GlasSense. Typically, activated by subtle contraction and relaxation of a temporalis muscle, there is a cyclic movement of the temporomandibular joint during mastication. However, such muscular signals are, in general, too weak to sense without amplification or an electromyographic analysis. To detect these oscillatory facial signals without any use of obtrusive device, we incorporated a load cell into each hinge which was used as a lever mechanism on both sides of the glasses. Thus, the signal measured at the load cells can detect the force amplified mechanically by the hinge. We demonstrated a proof-of-concept validation of the amplification by differentiating the force signals between the hinge and the temple. A pattern recognition was applied to extract statistical features and classify featured behavioral patterns, such as natural head movement, chewing, talking, and wink. The overall results showed that the average F1 score of the classification was about 94.0% and the accuracy above 89%. We believe this approach will be helpful for designing a non-intrusive and un-obtrusive eyewear-based ingestive behavior monitoring system.

  20. A glasses-type wearable device for monitoring the patterns of food intake and facial activity

    PubMed Central

    Chung, Jungman; Chung, Jungmin; Oh, Wonjun; Yoo, Yongkyu; Lee, Won Gu; Bang, Hyunwoo

    2017-01-01

    Here we present a new method for automatic and objective monitoring of ingestive behaviors in comparison with other facial activities through load cells embedded in a pair of glasses, named GlasSense. Typically, activated by subtle contraction and relaxation of a temporalis muscle, there is a cyclic movement of the temporomandibular joint during mastication. However, such muscular signals are, in general, too weak to sense without amplification or an electromyographic analysis. To detect these oscillatory facial signals without any use of obtrusive device, we incorporated a load cell into each hinge which was used as a lever mechanism on both sides of the glasses. Thus, the signal measured at the load cells can detect the force amplified mechanically by the hinge. We demonstrated a proof-of-concept validation of the amplification by differentiating the force signals between the hinge and the temple. A pattern recognition was applied to extract statistical features and classify featured behavioral patterns, such as natural head movement, chewing, talking, and wink. The overall results showed that the average F1 score of the classification was about 94.0% and the accuracy above 89%. We believe this approach will be helpful for designing a non-intrusive and un-obtrusive eyewear-based ingestive behavior monitoring system. PMID:28134303

  1. Potato aphid salivary proteome: enhanced salivation using resorcinol and identification of aphid phosphoproteins.

    PubMed

    Chaudhary, Ritu; Atamian, Hagop S; Shen, Zhouxin; Briggs, Steven P; Kaloshian, Isgouhi

    2015-04-03

    Aphids deliver saliva into plants and acquire plant sap for their nourishment using a specialized mouthpart or stylets. Aphid saliva is of great importance because it contains effectors that are involved in modulating host defense and metabolism. Although profiling aphid salivary glands and identifying secreted proteins have been successfully used, success in direct profiling of aphid saliva have been limited due to scarcity of saliva collected in artificial diets. Here we present the use of a neurostimulant, resorcinol, for inducing aphid salivation. Saliva of potato aphids (Macrosiphum euphorbiae), maintained on tomato, was collected in resorcinol diet. Salivary proteins were identified using mass spectrometry and compared with the existing M. euphorbiae salivary proteome collected in water. Comparative analysis was also performed with existing salivary proteomes from additional aphid species. Most of the proteins identified in the resorcinol diet were also present in the water diet and represented proteins with a plethora of functions in addition to a large number of unknowns. About half of the salivary proteins were not predicted for secretion or had canonical secretion signal peptides. We also analyzed the phosphorylation states of M. euphorbiae salivary proteins and identified three known aphid effectors, Me_WB01635/Mp1, Me10/Mp58, and Me23 that carry phosphorylation marks. In addition to insect proteins, tomato host proteins were also identified in aphid saliva. Our results indicate that aphid saliva is complex and provides a rich resource for functional characterization of effectors.

  2. Food stress prompts dispersal behavior in apterous pea aphids: do activated aphids incur energy loss?

    PubMed

    Tabadkani, Seyed Mohammad; Ahsaei, Seyed Mohammad; Hosseininaveh, Vahid; Nozari, Jamasb

    2013-02-17

    The pea aphid, Acyrthosiphon pisum (Hem: Aphididae), has been repeatedly used as a model species in a wide range of biological studies including genetics, ecology, physiology, and behavior. When red pea aphids feed on low quality plants in crowded conditions, some individuals lose their color shade and become pale yellowish, while other individuals on the same host plants remain changeless. The pale aphids have been shown to walk significantly faster and migrate more frequently to neighboring plants compared to the original red ones. We hypothesized that the color change and higher activity of pale aphids are directly associated with their suboptimal nutritional status. We showed that the pale aphids have significantly lower wet and dry weights than red ones. Analyses of energy reserves in individual aphids revealed that the pale aphids suffer a significant loss in their lipid and soluble carbohydrate contents. Our results provide a strong link between host quality, body color, dispersal rate, and energy reserves of pea aphids. Apparently, utilization of energy reserves resulted from an imbalance in food sources received by the aphids stimulates them to walk more actively to find new hosts and restore their lost energy. This reversible shift enables aphids to quickly respond to deprived host plants much earlier than the appearance of winged morph and restore their original status when they find appropriate host.

  3. Trophic relationships between aphids and their primary parasitoids.

    PubMed

    Khan, Imtinan A; Naeem, Muhammad; Hassan, Soaib A; Bilal, Hazrat; Ata-ul-Mohsin; Bodlah, Imran

    2012-01-01

    The present research was carried out to study the trophic relationship between aphids and their primary parasitoids in Pothwar, Pakistan during 2009-2010 in the districts of Rawalpindi, Attock, Chakwal, and Jhelum. Ten species of aphids were recorded from 17 host plants. The aphids were parasitized by 11 species of primary parasitoids. Five quantitative aphid-parasitoid food webs were constructed describing the trophic relationships between the community of aphids and their primary parasitoids.

  4. Plant resistance to aphid feeding: behavioral, physiological, genetic and molecular cues regulate aphid host selection and feeding.

    PubMed

    Smith, C Michael; Chuang, Wen-Po

    2014-04-01

    Aphids damage major world food and fiber crops through direct feeding and transmission of plant viruses. Fortunately, the development of many aphid-resistant crop plants has provided both ecological and economic benefits to food production. Plant characters governing aphid host selection often dictate eventual plant resistance or susceptibility to aphid herbivory, and these phenotypic characters have been successfully used to map aphid resistance genes. Aphid resistance is often inherited as a dominant trait, but is also polygenic and inherited as recessive or incompletely dominant traits. Most aphid-resistant cultivars exhibit constitutively expressed defenses, but some cultivars exhibit dramatic aphid-induced responses, resulting in the overexpression of large ensembles of putative aphid resistance genes. Two aphid resistance genes have been cloned. Mi-1.2, an NBS-LRR gene from wild tomato, confers resistance to potato aphid and three Meloidogyne root-knot nematode species, and Vat, an NBS-LRR gene from melon, controls resistance to the cotton/melon aphid and to some viruses. Virulence to aphid resistance genes of plants occurs in 17 aphid species--more than half of all arthropod biotypes demonstrating virulence. The continual appearance of aphid virulence underscores the need to identify new sources of resistance of diverse sequence and function in order to delay or prevent biotype development.

  5. Facultative symbiont infections affect aphid reproduction.

    PubMed

    Simon, Jean-Christophe; Boutin, Sébastien; Tsuchida, Tsutomu; Koga, Ryuichi; Le Gallic, Jean-François; Frantz, Adrien; Outreman, Yannick; Fukatsu, Takema

    2011-01-01

    Some bacterial symbionts alter their hosts reproduction through various mechanisms that enhance their transmission in the host population. In addition to its obligatory symbiont Buchnera aphidicola, the pea aphid Acyrthosiphon pisum harbors several facultative symbionts influencing several aspects of host ecology. Aphids reproduce by cyclical parthenogenesis whereby clonal and sexual reproduction alternate within the annual life cycle. Many species, including the pea aphid, also show variation in their reproductive mode at the population level, with some lineages reproducing by cyclical parthenogenesis and others by permanent parthenogenesis. While the role of facultative symbionts has been well studied during the parthenogenetic phase of their aphid hosts, very little is known on their possible influence during the sexual phase. Here we investigated whether facultative symbionts modulate the capacity to produce sexual forms in various genetic backgrounds of the pea aphid with controlled symbiont composition and also in different aphid genotypes from natural populations with previously characterized infection status and reproductive mode. We found that most facultative symbionts exhibited detrimental effects on their hosts fitness under sex-inducing conditions in comparison with the reference lines. We also showed that the loss of sexual phase in permanently parthenogenetic lineages of A. pisum was not explained by facultative symbionts. Finally, we demonstrated that Spiroplasma infection annihilated the production of males in the host progeny by inducing a male-killing phenotype, an unexpected result for organisms such as aphids that reproduce primarily through clonal reproduction.

  6. Are ant-aphid associations a tritrophic interaction? Oleander aphids and Argentine ants.

    PubMed

    Bristow, C M

    1991-09-01

    Oleander aphids, (Aphis nerii), which are sporadically tended by ants, were used as a moded system to examine whether host plant factors associated with feeding site influenced the formation of ant-aphid associations. Seasonal patterns of host plant utilization and association with attendant ants were examined through bi-weekly censuses of the aphid population feeding on thirty ornamental oleander plands (Nerium oleander) in northern California in 1985 and 1986. Colonies occurred on both developing and senescing plant terminals, including leaf tips, floral structures, and pods. Aphids preferentially colonized leaf terminals early in the season, but showed no preference for feeding site during later periods. Argentine ants (Iridomyrmex humilis) occasionally tended aphid colonies. Colonies on floral tips were three to four times more likely to attract ants than colonies on leaf tips, even though the latter frequently contained more aphids. Ants showed a positive recruitment response to colonies on floral tips, with a significant correlation between colony size and number of ants. There was no recruitment response to colonies on leaf tips. These patterns were reproducible over two years despite large fluctuations in both aphid population density and ant activity. In a laboratory bioassay of aphid palatability, the generalist predator,Hippodamia convergens, took significantly more aphids reared on floral tips compared to those reared on leaf tips. The patterns reported here support the hypothesis that tritrophic factors may be important in modifying higher level arthropod mutualisms.

  7. Rag1 aphid resistant soybeans alter the movement and distribution of soybean aphid (Hemiptera: Aphididae).

    PubMed

    Whalen, Rebecca; Harmon, Jason P

    2012-12-01

    Herbivorous insects often move and distribute according to the quality of the plant they are on, and this behavior could influence interactions with plants bred for herbivore resistance. However, when an insect is normally considered sedentary, less is known about the potential importance of movement. We performed experiments to determine if a resistant soybean variety alters the movement and distribution, both within and between plants, of the soybean aphid Aphis glycines Matsumura. We did this by counting apterous aphids on leaves of resistant and susceptible soybean plants across several days. In individual plant tests aphid distribution was different between susceptible and resistant soybeans. Most notably aphids on resistant plants were quickly found off the original leaf on which they were placed and were ultimately distributed throughout the resistant soybean. Aphids on susceptible plants, however, tended to stay on their initial leaf of placement. Follow up experiments indicated this was primarily because of the movement of individuals and not differential demography on various plant parts. In experiments where aphids were able to walk to an adjacent plant there appeared to be a net movement of aphids off resistant plants and on to susceptible plants. Aphid populations on susceptible plants were higher when the plant was adjacent to a resistant plant than when adjacent to another susceptible plant. The effect of resistant plants on aphid movement and distribution could lead to unintended side-effects such as greater spread of plant viruses or altered effectiveness of biological control agents.

  8. Transgenerational effects and the cost of ant tending in aphids.

    PubMed

    Tegelaar, Karolina; Glinwood, Robert; Pettersson, Jan; Leimar, Olof

    2013-11-01

    In mutualistic interactions, partners obtain a net benefit, but there may also be costs associated with the provision of benefits for a partner. The question of whether aphids suffer such costs when attended by ants has been raised in previous work. Transgenerational effects, where offspring phenotypes are adjusted based on maternal influences, could be important in the mutualistic interaction between aphids and ants, in particular because aphids have telescoping generations where two offspring generations can be present in a mature aphid. We investigated the immediate and transgenerational influence of ant tending on aphid life history and reproduction by observing the interaction between the facultative myrmecophile Aphis fabae and the ant Lasius niger over 13 aphid generations in the laboratory. We found that the effect of ant tending changes dynamically over successive aphid generations after the start of tending. Initially, total aphid colony weight, aphid adult weight and aphid embryo size decreased compared with untended aphids, consistent with a cost of ant association, but these differences disappeared within four generations of interaction. We conclude that transgenerational effects are important in the aphid-ant interactions and that the costs for aphids of being tended by ants can vary over generations.

  9. Organisms for Teaching: The Biology of Aphids.

    ERIC Educational Resources Information Center

    Llewellyn, M.

    1984-01-01

    Background information on the biology of aphids is supplied. Using this information in a wide variety of investigations, many involving equipment and techniques available in the school laboratory, can be carried out. An appendix lists possible projects. (Author)

  10. Organisms for Teaching: The Biology of Aphids.

    ERIC Educational Resources Information Center

    Llewellyn, M.

    1984-01-01

    Background information on the biology of aphids is supplied. Using this information in a wide variety of investigations, many involving equipment and techniques available in the school laboratory, can be carried out. An appendix lists possible projects. (Author)

  11. Long range migration of aphids into Sweden

    NASA Astrophysics Data System (ADS)

    Wiktelius, Staffan

    1984-09-01

    A five year study of migration of aphids across the southern part of the Baltic Sea is reported. The aphids were caught in a suction trap placed on a lighthouse 50 m from the shoreline. Large sections of the results are presented as case studies i.e. catches of aphids from periods containing at least three consecutive days with a southerly gradient wind. Some periods contained large and diverse catches and it is assumed that aphids regularly cross the Baltic Sea. The catches was largest on days when a cold front passed the trapping site within a period. More Myzus persicae were caught on days when the wind was southerly than on days with a northerly wind direction.

  12. RNAi-mediated plant protection against aphids.

    PubMed

    Yu, Xiu-Dao; Liu, Zong-Cai; Huang, Si-Liang; Chen, Zhi-Qin; Sun, Yong-Wei; Duan, Peng-Fei; Ma, You-Zhi; Xia, Lan-Qin

    2016-06-01

    Aphids (Aphididae) are major agricultural pests that cause significant yield losses of crop plants each year by inflicting damage both through the direct effects of feeding and by vectoring harmful plant viruses. Expression of double-stranded RNA (dsRNA) directed against suitable insect target genes in transgenic plants has been shown to give protection against pests through plant-mediated RNA interference (RNAi). Thus, as a potential alternative and effective strategy for insect pest management in agricultural practice, plant-mediated RNAi for aphid control has received close attention in recent years. In this review, the mechanism of RNAi in insects and the so far explored effective RNAi target genes in aphids, their potential applications in the development of transgenic plants for aphid control and the major challenges in this regard are reviewed, and the future prospects of using plant-mediated RNAi for aphid control are discussed. This review is intended to be a helpful insight into the generation of aphid-resistant plants through plant-mediated RNAi strategy. © 2016 Society of Chemical Industry.

  13. AphID (Lucid key) http://AphID.AphidNet.org

    USDA-ARS?s Scientific Manuscript database

    This peer-reviewed web site concentrates on the 66 adult alate and apterous aphids that are the world's most cosmopolitan and polyphagous species. The site includes fact sheets about the various aphids species, a glossary of terms helpful to the student, hundreds of photographs and illustrations, a...

  14. How aphids lose their marbles.

    PubMed Central

    Pike, Nathan; Richard, Denis; Foster, William; Mahadevan, L

    2002-01-01

    Insects provide examples of many cunning stratagems to cope with the challenges of living in a world dominated by surface forces. Despite being the current masters of the land environment, they are at constant risk of being entrapped in liquids, which they prevent by having waxy and hairy surfaces. The problem is particularly acute in an enclosed space, such as a plant gall. Using secreted wax to efficiently parcel and transport their own excrement, aphids were able to solve this problem 200 Myr ago. Here, we report on the physical and physiological significance of this ingenious solution. The secreted powdery wax has three distinct roles: (i) it is hydrophobic, (ii) it creates a microscopically rough inner gall surface made of weakly compacted wax needles making the gall ultra-hydrophobic, and (iii) it coats the honeydew droplets converting them into liquid marbles, that can be rapidly and efficiently moved. PMID:12065036

  15. Modulation of aphid alarm pheromone emission of pea aphid prey by predators.

    PubMed

    Joachim, Christoph; Hatano, Eduardo; David, Anja; Kunert, Maritta; Linse, Cornelia; Weisser, Wolfgang W

    2013-06-01

    Recent studies on animal alarm signaling have shown that alarm calls generally are not uniform, but may vary depending on the type and intensity of threat. While alarm call variability has been studied intensively in birds and mammals, little is known about such variation in insects. We investigated variability in alarm signaling in aphids, group-living insect herbivores. Under attack, aphids release droplets containing a volatile alarm pheromone, (E)-β-farnesene (EBF), that induces specific escape behavior in conspecifics. We used a handheld gas chromatograph (zNose™), which allows real-time volatile analysis, to measure EBF emission by pea aphids, Acyrthosiphon pisum, under attack from different predators, lacewing or ladybird larvae. We demonstrate that aphid alarm signaling is affected by the predator species attacking. Ladybirds generally elicited smaller EBF emission peaks and consumed aphids more quickly, resulting in lower total EBF emission compared to lacewing attacks. In 52 % of the replicates with lacewings and 23 % with ladybirds, no EBF was detectable in the headspace, although aphids secreted cornicle droplets after attack. We, therefore, examined EBF amounts contained in these droplets and the aphid body. While all aphid bodies always contained EBF, many secreted droplets did not. Our experiments show that alarm signaling in insects can be variable, and both the attacker as well as the attacked may affect alarm signal variation. While underlying mechanisms of such variation in aphid-predator interactions need to be investigated in more detail, we argue that at least part of this variation may be adaptive for the predator and the aphid.

  16. Plant derived compounds and extracts with potential as aphid repellents

    USDA-ARS?s Scientific Manuscript database

    We devised a method for screening various substances for possible aphid repellency. Corn leaf aphids (Rhopalosiphum maidis) were released in an arena and allowed to select paired green tiles coated with petroleum jelly alone or petroleum jelly containing 1% of the substance being tested. Aphids ad...

  17. Evaluation of aphid resistance among sugarcane cultivars in Louisiana

    USDA-ARS?s Scientific Manuscript database

    Sugarcane, interspecific hybrids of Saccharum spp., in Louisiana is colonized by two aphid species, the sugarcane aphid, Melanaphis sacchari (Zehntner), and the yellow sugarcane aphid, Sipha flava (Forbes). Five sugarcane cultivars, LCP 85-384, HoCP 91-555, Ho 95-988, HoCP 96-540, and L 97-128, rep...

  18. Root-Lesion Nematodes Suppress Cabbage Aphid Population Development by Reducing Aphid Daily Reproduction

    PubMed Central

    Hol, W. H. G.; Raaijmakers, Ciska E.; Mons, Ilse; Meyer, Katrin M.; van Dam, Nicole M.

    2016-01-01

    Empirical studies have shown that belowground feeding herbivores can affect the performance of aboveground herbivores in different ways. Often the critical life-history parameters underlying the observed performance effects remain unexplored. In order to better understand the cause for the observed effects on aboveground herbivores, these ecological mechanisms must be better understood. In this study we combined empirical experiments with a modeling approach to analyze the effect of two root feeding endoparasitic nematodes with different feeding strategies on the population growth of the aboveground feeding specialist aphid Brevicoryne brassicae on Brassica nigra. The aim was to test whether emerging differences in life history characteristics (days until reproduction, daily reproduction) would be sufficient to explain observed differences in aphid population development on plants with and without two species of nematodes. Aphid numbers were lower on plants with Pratylenchus penetrans in comparison to aphid numbers on plants with Meloidogyne spp. A dedicated experiment showed that aphid daily reproduction was lower on plants with P. penetrans (3.08 offspring female–1 day–1) in comparison to both uninfested plants and plants with Meloidogyne spp. (3.50 offspring female–1 day–1). The species-specific reduction of aphid reproduction appeared independent of changes in amino acids, soluble sugars or the glucosinolate sinigrin in the phloem. An individual-based model revealed that relatively small differences in reproduction rate per female were sufficient to yield a similar difference in aphid populations as was found in the empirical experiments. PMID:26904074

  19. Effects of aposymbiotic and symbiotic aphids on parasitoid progeny development and adult oviposition behavior within aphid instars.

    PubMed

    Cheng, Rui-Xia; Meng, Ling; Li, Bao-Ping

    2010-04-01

    This study aims at exploring the potential relationship between aphidiine parasitoid development and the primary endosymbiont in aphids by focusing on specific aphid instars and the relative effects on parasitoid oviposition behavior and progeny development. Lysiphlebus ambiguus (Aphidiidae, Hymenoptera) is a solitary parasitoid of several species of aphids, including Aphis fabae. In this study, A. fabae was treated with antibiotic rifampicin to obtain aposymbiotic hosts and exposed to parasitism. L. ambiguus launched significantly more attacks on symbiotic L(2) (the second instar), aposymbiotic L(3) (the third instar) and L(4) (the forth instar) hosts than on the corresponding hosts at the same age. L. ambiguus also parasitized more L(1) aphids compared with adults irrespective of whether the aphid was asymbiotic or not. Pupa mortality rate of parasitoid progeny was significantly lower from aposymbiotic hosts than from the corresponding symbiotics at all stages. Female-biased parasitoid progeny was produced from aposymbiotic aphids without respect to host ages, but female progeny increased linearly with host ages at parasitism from symbiotic aphids. Body size of parasitoid progeny increased linearly with host instars at parasitism in symbiotic aphids but did not significantly change across host instars in aposymbiotic aphids. The offspring parasitoids turned out to be generally large in body size from attacking aposymbiotic aphids compared with the symbiotics. Development time of egg-to-adult of parasitoid progeny decreased with host instars in both symbiotic and aposymbiotic aphids but was generally much longer in aposymbiotic aphids than in symbiotic aphids. Our study suggests that age or body size of host aphids may not be the only cue exercised by L. ambiguus to evaluate host quality and that offspring parasitoids may be able to compensate for the nutrition stress associated with disruption of primary endosymbiotc bacteria in aposymbiotic aphids.

  20. The whole genome sequence assembly of the soybean aphid, Aphis glycines

    USDA-ARS?s Scientific Manuscript database

    Aphids are emerging as model organisms for both basic and applied research. Of the 5,000 estimated species, only two aphids have published whole genome sequences: the pea aphid Acyrthosiphon pisum, and the Russian wheat aphid, Diuraphis noxia. The soybean aphid (Aphis glycines) is an extreme special...

  1. Engineering plants for aphid resistance: current status and future perspectives.

    PubMed

    Yu, Xiudao; Wang, Genping; Huang, Siliang; Ma, Youzhi; Xia, Lanqin

    2014-10-01

    The current status of development of transgenic plants for improved aphid resistance, and the pros and cons of different strategies are reviewed and future perspectives are proposed. Aphids are major agricultural pests that cause significant yield losses of crop plants each year. Excessive dependence on insecticides for aphid control is undesirable because of the development of insecticide resistance, the potential negative effects on non-target organisms and environmental pollution. Transgenic plants engineered for resistance to aphids via a non-toxic mode of action could be an efficient alternative strategy. In this review, the distribution of major aphid species and their damages on crop plants, the so far isolated aphid-resistance genes and their applications in developments of transgenic plants for improved aphid resistance, and the pros and cons of these strategies are reviewed and future perspectives are proposed. Although the transgenic plants developed through expressing aphid-resistant genes, manipulating plant secondary metabolism and plant-mediated RNAi strategy have been demonstrated to confer improved aphid resistance to some degree. So far, no aphid-resistant transgenic crop plants have ever been commercialized. This commentary is intended to be a helpful insight into the generation and future commercialization of aphid-resistant transgenic crops in a global context.

  2. Partial aphid resistance in lettuce negatively affects parasitoids.

    PubMed

    Lanteigne, Marie-Eve; Brodeur, Jacques; Jenni, Sylvie; Boivin, Guy

    2014-10-01

    This study investigated the effects of partial plant resistance on the lettuce aphid Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae), a major pest of cultivated lettuce (Lactuca sativa L.), and one of its parasitoids, Aphidius ervi Haliday (Hymenoptera: Braconidae). Aphids were reared on susceptible (L. sativa variety Estival; S) or partially resistant (Lactuca serriola L. PI 491093; PR) lettuce, and next parasitized by A. ervi females. Fitness proxies were measured for both aphids and parasitoids. Developmental time to adult stage took longer for alate and apterous aphids (an average of 3.5 and 1.5 additional days, respectively) on PR than on S lettuce, and fecundity of alate aphids reared on PR lettuce was reduced by 37.8% relative to those reared on S lettuce. Size (tibia length) and weight of aphids reared on PR lettuce were lower than for aphids reared on S lettuce from the third and second instar onward, respectively. Parasitism of aphids reared on PR plants resulted in lower parasitoid offspring emergence (-49.9%), lower adult female (-30.3%) and male (-27.5%) weight, smaller adult female (-17.5%) and male (-11.9%) size, and lower female fecundity (37.8% fewer eggs) than when parasitoids developed from aphids reared on S plants. Our results demonstrate that partial aphid resistance in lettuce negatively affects both the second and third trophic levels. Host plant resistance in cultivated lettuce may therefore create an ecological sink for aphid parasitoids.

  3. Early interactions during the encounter of plants, aphids and arboviruses.

    PubMed

    Bak, Aurélie; Martinière, Alexandre; Blanc, Stéphane; Drucker, Martin

    2013-06-01

    Aphids infest many plants and cause damage by depriving them of nutrients and by transmitting many viral diseases. Aphid infestation and arbovirus transmission are controlled by establishment (or not) of a compatible reaction between the insects and the plants. This reaction is the result of defense reactions of the plant and counter-defense reactions of the parasite. Contrarily to plant-bacteria, plant-fungi and plant-herbivorous insects pathosystems, the plant-aphid pathosystem is understudied, although recent advances have begun to uncover some of its details. Especially the very early steps in plant-aphid interactions are hardly known. We here resume the present knowledge of these interactions. We discuss further how an aphid-transmitted plant virus that is transmitted during the first moments of the plant-aphid encounter, might help to study the very early plant aphid interactions.

  4. Early interactions during the encounter of plants, aphids and arboviruses

    PubMed Central

    Bak, Aurélie; Martinière, Alexandre; Blanc, Stéphane; Drucker, Martin

    2013-01-01

    Aphids infest many plants and cause damage by depriving them of nutrients and by transmitting many viral diseases. Aphid infestation and arbovirus transmission are controlled by establishment (or not) of a compatible reaction between the insects and the plants. This reaction is the result of defense reactions of the plant and counter-defense reactions of the parasite. Contrarily to plant-bacteria, plant-fungi and plant-herbivorous insects pathosystems, the plant-aphid pathosystem is understudied, although recent advances have begun to uncover some of its details. Especially the very early steps in plant-aphid interactions are hardly known. We here resume the present knowledge of these interactions. We discuss further how an aphid-transmitted plant virus that is transmitted during the first moments of the plant-aphid encounter, might help to study the very early plant aphid interactions. PMID:23518584

  5. Preventive control of aphids in ornamental plants with complementary parasitoids.

    PubMed

    Dassonville, N; Thielemans, T; Ruisinger, M; Rosemeyer, V

    2012-01-01

    Biological control of aphids can be achieved with parasitoids. A parasitoid is a wasp able to parasitize aphids in a host-specific way. These natural enemies of aphids are used in organic or integrated pest management strategies. In order to apply the matching parasitoid against a given aphid species, the aphid has to be detected in the crop and subsequently identified. By the time the aphids are spotted by the grower and then identified by himself or a specialist, it is usually more difficult to gain control over an increasing aphid population. Viridaxis developed a new concept of aphid control, based not on the species identified but on the crop treated. There was a need for a product controlling the largest possible spectrum of aphid species susceptibly present in ornamental crops. As the first step of development, an inventory of the aphid species attacking ornamental crops was made in various regions. A unique cocktail of parasitoids species (OrnaProtect) controlling all these aphids was then developed. OrnaProtect contains six different species of natural aphid enemies, and is able to control all commonly appearing aphids attacking ornamental crops. The fact of mixing different species not only covers the entire spectrum of aphids, but also contributes to prolonged hatching. To reinforce this long lasting emergence, mummies of different ages are mixed, older mummies (stored at low temperature) emerging earlier after release than young mummies. With that prolonged hatching dynamics, a release every two weeks assures a permanent presence of fresh adult parasitoids in the crop. The ready-to-use units of OrnaProtect contain an integrated feeding point which contributes to longevity and efficiency of the parasitoids. Its application in the crop is much faster than even any chemical treatment. Here, we show the results of trials made with OrnaProtect in 2011 on several crops (Hydrangea macrophylla, Solanum jasminoides, Argyranthemum frutescens and Osteospermum

  6. Plant-Aphid Interactions Under Elevated CO2: Some Cues from Aphid Feeding Behavior.

    PubMed

    Sun, Yucheng; Guo, Huijuan; Ge, Feng

    2016-01-01

    Although the increasing concentration of atmospheric carbon dioxide (CO2) accelerates the accumulation of carbohydrates and increases the biomass and yield of C3 crop plants, it also reduces their nitrogen concentration. The consequent changes in primary and secondary metabolites affect the palatability of host plants and the feeding of herbivorous insects. Aphids are phloem feeders and are considered the only feeding guild that positively responds to elevated CO2. In this review, we consider how elevated CO2 modifies host defenses, nutrients, and water-use efficiency by altering concentrations of the phytohormones jasmonic acid, salicylic acid, ethylene, and abscisic acid. We will describe how these elevated CO2-induced changes in defenses, nutrients, and water statusfacilitate specific stages of aphid feeding, including penetration, phloem-feeding, and xylem absorption. We conclude that a better understanding of the effects of elevated CO2 on aphids and on aphid damage to crop plants will require research on the molecular aspects of the interaction between plant and aphid but also research on aphid interactions with their intra- and inter-specific competitors and with their natural enemies.

  7. Plant–Aphid Interactions Under Elevated CO2: Some Cues from Aphid Feeding Behavior

    PubMed Central

    Sun, Yucheng; Guo, Huijuan; Ge, Feng

    2016-01-01

    Although the increasing concentration of atmospheric carbon dioxide (CO2) accelerates the accumulation of carbohydrates and increases the biomass and yield of C3 crop plants, it also reduces their nitrogen concentration. The consequent changes in primary and secondary metabolites affect the palatability of host plants and the feeding of herbivorous insects. Aphids are phloem feeders and are considered the only feeding guild that positively responds to elevated CO2. In this review, we consider how elevated CO2 modifies host defenses, nutrients, and water-use efficiency by altering concentrations of the phytohormones jasmonic acid, salicylic acid, ethylene, and abscisic acid. We will describe how these elevated CO2-induced changes in defenses, nutrients, and water statusfacilitate specific stages of aphid feeding, including penetration, phloem-feeding, and xylem absorption. We conclude that a better understanding of the effects of elevated CO2 on aphids and on aphid damage to crop plants will require research on the molecular aspects of the interaction between plant and aphid but also research on aphid interactions with their intra- and inter-specific competitors and with their natural enemies. PMID:27148325

  8. National Plant Diagnostic Network, Taxonomic training videos: Introduction to Aphids - Part 1

    USDA-ARS?s Scientific Manuscript database

    Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides visual instruction on important subject areas for aphid examination and identification. Aphid topics such as classification, morphology, plant disease transmission, and references are discussed. This dis...

  9. First report of Pandora neoaphidis resting spore formation in vivo in aphid hosts under field conditions

    USDA-ARS?s Scientific Manuscript database

    The entomopathogenic fungus PANDORA NEOAPHIDIS is a recognized pathogen of aphids, causing natural epizootics in aphid populations, and interacts favorably with aphid predators and parasitoids. Survival of entomophthoralean fungi in periods of unsuitable weather conditions or lack of appropriate hos...

  10. Citrus tristeza virus-aphid interactions

    USDA-ARS?s Scientific Manuscript database

    A review chapter on aphid transmission of Citrus tristeza virus is provided for a book on “Vector-Mediated Transmission of Plant Pathogens”. Earliest uses of citrus goes back over two millennia as items of trade, gifts and medicinal compounds. Citrus propagation during this period was by seed and si...

  11. Sugarbeet root aphid on postharvest root storage

    USDA-ARS?s Scientific Manuscript database

    The sugarbeet root aphid (SBRA), Pemphigus betae Doane, is a serious insect pest of sugarbeet in several North American sugarbeet production areas; however, it is rarely an economic pest in the Red River Valley (RRV). In 2012 and 2013, all RRV factory districts were impacted by SBRA outbreaks, and ...

  12. Mechanisms Underlying the Nonconsumptive Effects of Parasitoid Wasps on Aphids.

    PubMed

    Ingerslew, K S; Finke, D L

    2017-02-01

    Natural enemies need not consume herbivores to suppress herbivore populations. Behavioral interactions can adversely impact herbivore fitness from reduced time feeding, investment in defense, or injury from failed attacks. The importance of such "nonconsumptive effects" for herbivore suppression may vary across species based on the specificity and intensity of the herbivore defensive response. In a series of manipulative studies, we quantified the nature and consequences of nonconsumptive interactions between two parasitoid wasps, Aphidius ervi Haliday and Aphidius colemani Viereck, on two aphid species, pea aphids (Acyrthosiphon pisum (Harris)) and green peach aphids (Myzus persicae (Sulzer)). Both wasps successfully parasitize green peach aphids, but only A. ervi parasitizes pea aphids. We observed A. ervi antennating and stinging pea aphids and documented a decrease in pea aphid longevity in response to stinging even when the aphid survived the interaction and no mummy formed. The primary defensive tactic of pea aphids in response to either wasp species was dropping from the host plant. Both wasp species antennated and stung green peach aphids, but they elicited unique defensive behaviors. Green peach aphids kicked or emitted cornicle secretions in response to A. colemani but spent more time off the plant in the presence of A. ervi. Green peach aphid longevity and fecundity were not affected by wasp stings when the aphid survived and no mummy formed. Our study demonstrates the complexity of behavioral interactions between parasitoids and their potential hosts and contributes to a mechanistic understanding of variation in the nonconsumptive suppression of herbivore populations. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. Aphid egg protection by ants: a novel aspect of the mutualism between the tree-feeding aphid Stomaphis hirukawai and its attendant ant Lasius productus

    NASA Astrophysics Data System (ADS)

    Matsuura, Kenji; Yashiro, Toshihisa

    2006-10-01

    Aphids often form mutualistic associations with ants, in which the aphids provide the ants with honeydew and the ants defend the aphids from predators. In this paper, we report aphid egg protection by ants as a novel aspect of the deeply interdependent relationship between a tree-feeding aphid and its attendant ant. The ant Lasius productus harbours oviparous females, males, and eggs of the hinoki cypress-feeding aphid Stomaphis hirukawai in its nests in winter. We investigated the behaviour of ants kept with aphid eggs in petri dishes to examine whether the ants recognise the aphid eggs and tend them or only provide a refuge for the aphids. Workers carried almost all of the aphid eggs into the nest within 24 h. The ants indiscriminately tended aphid eggs collected from their own colonies and those from other ant colonies. The ants cleaned the eggs and piled them up in the nest, and egg tending by ants dramatically increased aphid egg survival rates. Starving the ants showed no significant effect on aphid egg survivorship. Without ants, aphid eggs were rapidly killed by fungi. These results suggested that grooming by the ants protected the aphid eggs, at least, against pathogenic fungi. This hygienic service afforded by the ants seems indispensable for egg survival of these aphids in an environment rich in potentially pathogenic microorganisms.

  14. Probiotic effects of beta-glucuronidase on the peach-potato aphid Myzus persicae (Aphididae).

    PubMed

    Cherqui, A; Alla, S; Saguez, J; Doury, G; Sangwan-Norreel, B S; Giordanengo, P

    2003-12-01

    beta-glucuronidase (GUS) is a reporter protein commonly expressed in transgenic plants allowing the visualization of the transformed individuals. In our recent work, we showed that consumption of transformed potato plants expressing this GUS enzyme improves performance of the phloem feeding aphid Myzus persicae. Those results led us to the conclusion that the expression of GUS in potato plants might be responsible for the probiotic effect measured in feeding aphids. In the present paper, artificial diets were used to provide active GUS (10 and 500 microg ml(-1)), inactivated heated GUS (500 microg ml(-1)), glucuronic acid (10, 100 and 500 microg ml(-1)), and bovine serum albumin (500 microg ml(-1)) to M. persicae. Our results reveal that these chemicals provided as food intake might influence the biological parameters of this aphid. Experiments showed a probiotic effect of 500 microg ml(-1) GUS diet, resulting in reduced larval mortality, and increased adult reproduction period and fecundity, which led to an increased population growth potential (r(m)=0.17+/-0.01 versus r(m)=0.12+/-0.03 for aphids fed on control diet). A lower amount of added GUS led to fewer variations, biological parameters being only slightly altered (r(m)=0.14+/-0.03). Statistically similar alterations of the biological parameters were obtained when comparing aphids fed on the diet added with inactivated GUS or the non-structural bovine serum albumin protein (r(m)=0.15+/-0.02 and 0.14+/-0.03, respectively). Feeding assays conducted with glucuronic acid supplemented diets enhanced longevity and nymph production of the adult aphids and reduced larval mortality, resulting in r(m)=0.15+/-0.02 for the highest dose (500 microg ml(-1)). Although 100 microg ml(-1) glucuronate diet did not induce any effect on M. persicae (r(m)=0.12+/-0.03), aphids fed on 10 microg ml(-1) glucuronate diet exhibited unexpected reduced demographic parameters (r(m)=0.10+/-0.03). Immuno-histological analysis showed GUS

  15. A peptide that binds the pea aphid gut impedes entry of Pea enation mosaic virus into the aphid hemocoel

    SciTech Connect

    Liu Sijun; Sivakumar, S.; Sparks, Wendy O.; Miller, W. Allen; Bonning, Bryony C.

    2010-05-25

    Development of ways to block virus transmission by aphids could lead to novel and broad-spectrum means of controlling plant viruses. Viruses in the Luteoviridae enhanced are obligately transmitted by aphids in a persistent manner that requires virion accumulation in the aphid hemocoel. To enter the hemocoel, the virion must bind and traverse the aphid gut epithelium. By screening a phage display library, we identified a 12-residue gut binding peptide (GBP3.1) that binds to the midgut and hindgut of the pea aphid Acyrthosiphon pisum. Binding was confirmed by labeling the aphid gut with a GBP3.1-green fluorescent protein fusion. GBP3.1 reduced uptake of Pea enation mosaic virus (Luteoviridae) from the pea aphid gut into the hemocoel. GBP3.1 also bound to the gut epithelia of the green peach aphid and the soybean aphid. These results suggest a novel strategy for inhibiting plant virus transmission by at least three major aphid pest species.

  16. Research on recognition methods of aphid objects in complex backgrounds

    NASA Astrophysics Data System (ADS)

    Zhao, Hui-Yan; Zhang, Ji-Hong

    2009-07-01

    In order to improve the recognition accuracy among the kinds of aphids in the complex backgrounds, the recognition method among kinds of aphids based on Dual-Tree Complex Wavelet Transform (DT-CWT) and Support Vector Machine (Libsvm) is proposed. Firstly the image is pretreated; secondly the aphid images' texture feature of three crops are extracted by DT-CWT in order to get the training parameters of training model; finally the training model could recognize aphids among the three kinds of crops. By contrasting to Gabor wavelet transform and the traditional extracting texture's methods based on Gray-Level Co-Occurrence Matrix (GLCM), the experiment result shows that the method has a certain practicality and feasibility and provides basic for aphids' recognition between the identification among same kind aphid.

  17. NBS-LRR-mediated resistance triggered by aphids: viruses do not adapt; aphids adapt via different mechanisms.

    PubMed

    Boissot, Nathalie; Thomas, Sophie; Chovelon, Véronique; Lecoq, Hervé

    2016-01-22

    Aphids are serious pest on crops. By probing with their stylets, they interact with the plant, they vector viruses and when they reach the phloem they start a continuous ingestion. Many plant resistances to aphids have been identified, several have been deployed. However, some resistances breaking down have been observed. In the melon, a gene that confers resistance to aphids has been deployed in some melon-producing areas, and aphid colony development on Vat-carrying plants has been observed in certain agrosystems. The Vat gene is a NBS-LRR gene that confers resistance to the aphid species Aphis gossypii and exhibits the unusual characteristic of also conferring resistance to non-persistently transmitted viruses when they are inoculated by the aphid. Thus, we characterized patterns of resistance to aphid and virus using the aphid diversity and we investigated the mechanisms by which aphids and viruses may adapt to the Vat gene. Using a Vat-transgenic line built in a susceptible background, we described the Vat- spectrum of resistance to aphids, and resistance to viruses triggered by aphids using a set of six A. gossypii biotypes. Discrepancies between both resistance phenotypes revealed that aphid adaptation to Vat-mediated resistance does not occur only via avirulence factor alterations but also via adaptation to elicited defenses. In experiments conducted with three virus species serially inoculated by aphids from and to Vat plants, the viruses did not evolve to circumvent Vat-mediated resistance. We confirmed discrepancies between both resistance phenotypes by testing each aphid biotype with a set of thirteen melon accessions chosen to reflect the natural diversity of the melon. Inheritance studies revealed that patterns of resistance to virus triggered by aphids are controlled by different alleles at the Vat locus and at least another locus located at a short genetic distance. Therefore, resistance to viruses triggered by aphids is controlled by a gene cluster

  18. Aphid-encoded variability in susceptibility to a parasitoid

    PubMed Central

    2014-01-01

    Background Many animals exhibit variation in resistance to specific natural enemies. Such variation may be encoded in their genomes or derived from infection with protective symbionts. The pea aphid, Acyrthosiphon pisum, for example, exhibits tremendous variation in susceptibility to a common natural enemy, the parasitic wasp Aphidius ervi. Pea aphids are often infected with the heritable bacterial symbiont, Hamiltonella defensa, which confers partial to complete resistance against this parasitoid depending on bacterial strain and associated bacteriophages. That previous studies found that pea aphids without H. defensa (or other symbionts) were generally susceptible to parasitism, together with observations of a limited encapsulation response, suggested that pea aphids largely rely on infection with H. defensa for protection against parasitoids. However, the limited number of uninfected clones previously examined, and our recent report of two symbiont-free resistant clones, led us to explicitly examine aphid-encoded variability in resistance to parasitoids. Results After rigorous screening for known and unknown symbionts, and microsatellite genotyping to confirm clonal identity, we conducted parasitism assays using fifteen clonal pea aphid lines. We recovered significant variability in aphid-encoded resistance, with variation levels comparable to that contributed by H. defensa. Because resistance can be costly, we also measured aphid longevity and cumulative fecundity of the most and least resistant aphid lines under permissive conditions, but found no trade-offs between higher resistance and these fitness parameters. Conclusions These results indicate that pea aphid resistance to A. ervi is more complex than previously appreciated, and that aphids employ multiple tactics to aid in their defense. While we did not detect a tradeoff, these may become apparent under stressful conditions or when resistant and susceptible aphids are in direct competition. Understanding

  19. Armet is an effector protein mediating aphid-plant interactions.

    PubMed

    Wang, Wei; Dai, Huaien; Zhang, Yi; Chandrasekar, Raman; Luo, Lan; Hiromasa, Yasuaki; Sheng, Changzhong; Peng, Gongxin; Chen, Shaoliang; Tomich, John M; Reese, John; Edwards, Owain; Kang, Le; Reeck, Gerald; Cui, Feng

    2015-05-01

    Aphid saliva is predicted to contain proteins that modulate plant defenses and facilitate feeding. Armet is a well-characterized bifunctional protein in mammalian systems. Here we report a new role of Armet, namely as an effector protein in the pea aphid, Acyrthosiphon pisum. Pea aphid Armet's physical and chemical properties and its intracellular role are comparable to those reported for mammalian Armets. Uniquely, we detected Armet in aphid watery saliva and in the phloem sap of fava beans fed on by aphids. Armet's transcript level is several times higher in the salivary gland when aphids feed on bean plants than when they feed on an artificial diet. Knockdown of the Armet transcript by RNA interference disturbs aphid feeding behavior on fava beans measured by the electrical penetration graph technique and leads to a shortened life span. Inoculation of pea aphid Armet protein into tobacco leaves induced a transcriptional response that included pathogen-responsive genes. The data suggest that Armet is an effector protein mediating aphid-plant interactions. © FASEB.

  20. On the evolution of dispersal and altruism in aphids.

    PubMed

    Abbot, Patrick

    2009-10-01

    How competitive interactions and population structure promote or inhibit cooperation in animal groups remains a key challenge in social evolution. In eusocial aphids, there is no single explanation for what predisposes some lineages of aphids to sociality, and not others. Because the assumption has been that most aphid species occur in essentially clonal groups, the roles of intra- and interspecific competition and population structure in aphid sociality have been given little consideration. Here, I used microsatellites to evaluate the patterns of variation in the clonal group structure of both social and nonsocial aphid species. Multiclonal groups are consistent features across sites and host plants, and all species-social or not-can be found in groups composed of large fractions of multiple clones, and even multiple species. Between-group dispersal in gall-forming aphids is ubiquitous, implying that factors acting ultimately to increase between-clone interactions and decrease within-group relatedness were present in aphids prior to the origins of sociality. By demonstrating that between-group dispersal is common in aphids, and thus interactions between clones are also common, these results suggest that understanding the ecological dynamics of dispersal and competition may offer unique insights into the evolutionary puzzle of sociality in aphids.

  1. A facultative endosymbiont in aphids can provide diverse ecological benefits.

    PubMed

    Heyworth, E R; Ferrari, J

    2015-10-01

    Ecologically important traits of insects are often affected by facultative bacterial endosymbionts. This is best studied in the pea aphid Acyrthosiphon pisum, which is frequently infected by one or more of eight facultative symbiont species. Many of these symbiont species have been shown to provide one ecological benefit, but we have little understanding of the range of effects that a single strain can have. Here, we describe the phenotypes conferred by three strains of the recently discovered bacterium known as X-type (Enterobacteriaceae), each in their original aphid genotype which also carries a Spiroplasma symbiont. All comparisons are made between aphids that are coinfected with Spiroplasma and X-type and aphids of the same genotype that harbour only Spiroplasma. We show that in all cases, infection with X-type protects aphids from the lethal fungal pathogen Pandora neoaphidis, and in two cases, resistance to the parasitoid Aphidius ervi also increases. X-type can additionally affect aphid stress responses--the presence of X-type increased reproduction after the aphids were heat-stressed. Two of the three strains of X-type are able to provide all of these benefits. Under benign conditions, the aphids tended to suffer from reduced fecundity when harbouring X-type, a mechanism that might maintain intermediate frequencies in field populations. These findings highlight that a single strain of a facultative endosymbiont has the potential to provide diverse benefits to its aphid host.

  2. Secondary bacterial symbiont community in aphids responds to plant diversity.

    PubMed

    Zytynska, Sharon E; Meyer, Sebastian T; Sturm, Sarah; Ullmann, Wiebke; Mehrparvar, Mohsen; Weisser, Wolfgang W

    2016-03-01

    Biodiversity is important for ecosystem functioning and biotic interactions. In experimental grasslands, increasing plant species richness is known to increase the diversity of associated herbivores and their predators. If these interactions can also involve endosymbionts that reside within a plant or animal host is currently unknown. In plant-feeding aphids, secondary bacterial symbionts can have strong fitness effects on the host, e.g. resistance to natural enemies or fungal pathogens. We examined the secondary symbiont community in three species of aphid, each feeding on a unique host plant across experimental plots that varied in plant species richness. Aphids were collected in May and June, and the symbiont community identified using species-specific PCR assays. Aphis fabae aphids were found to host six different symbiont species with individual aphids co-hosting up to four symbionts. Uroleucon jaceae and Macrosiphum rosae hosted two and three symbiont species, respectively. We found that, at the aphid population level, increasing plant species richness increased the diversity of the aphid symbiont community, whereas at the individual aphid level, the opposite was found. These effects are potentially driven by varying selective pressures across different plant communities of varying diversities, mediated by defensive protection responses and a changing cost-benefit trade-off to the aphid for hosting multiple secondary symbionts. Our work extends documented effects of plant diversity beyond visible biotic interactions to changes in endosymbiont communities, with potentially far-reaching consequences to related ecosystem processes.

  3. Watery Saliva Secreted by the Grain Aphid Sitobion avenae Stimulates Aphid Resistance in Wheat.

    PubMed

    Zhang, Yong; Fan, Jia; Francis, Frédéric; Chen, Julian

    2017-09-27

    Infestation with Sitobion avenae induces localized defense responses in wheat; in this study, the role of S. avenae watery saliva in resistance induction was examined by infiltrating aphid saliva into wheat leaves. After feeding S. avenae on an artificial diet for 48 h, we first collected watery saliva from them and then separated the salivary proteins using one-dimensional gel electrophoresis. Gene expression studies showed that infiltration of S. avenae watery saliva in wheat leaves induced a strong salicylic acid-responsive defense but moderate jasmonic acid-dependent defense. Feeding on wheat leaves infiltrated with aphid saliva, compared with untreated leaves, significantly decreased the number of nymphs produced per day and the intrinsic rate of increase of the population of S. avenae. In a choice test against untreated wheat, saliva-infiltrated wheat had repellent effects on aphids. Additionally, electrical penetration graph results showed that the feeding behavior of S. avenae on saliva-treated wheat was negatively affected compared with that on untreated wheat. These findings provided direct evidence that salivary components of S. avenae are involved in the induction of wheat resistance against aphids and further demonstrated the important roles of watery saliva in aphid-plant interactions.

  4. Aphid reproductive investment in response to mortality risks

    PubMed Central

    2010-01-01

    Background Aphids are striking in their prodigious reproductive capacity and reliance on microbial endosymbionts, which provision their hosts with necessary amino acids and provide protection against parasites and heat stress. Perhaps as a result of this bacterial dependence, aphids have limited immune function that may leave them vulnerable to bacterial pathogens. An alternative, non-immunological response that may be available to infected aphids is to increase reproduction, thereby ameliorating fitness loss from infection. Such a response would reduce the need to mount a potentially energetically costly immune response, and would parallel that of other hosts that alter life-history traits when there is a risk of infection. Here we examined whether pea aphids (Acyrthosiphon pisum) respond to immunological challenges by increasing reproduction. As a comparison to the response to the internal cue of risk elicited by immunological challenge, we also exposed pea aphids to an external cue of risk - the aphid alarm pheromone (E)-β-farnesene (EBF), which is released in the presence of predators. For each challenge, we also examined whether the presence of symbionts modified the host response, as maintaining host fitness in the face of challenge would benefit both the host and its dependent bacteria. Results We found that aphids stabbed abdominally with a sterile needle had reduced fecundity relative to control aphids but that aphids stabbed with a needle bearing heat-killed bacteria had reproduction intermediate, and statistically indistinguishable, to the aphids stabbed with a sterile needle and the controls. Aphids with different species of facultative symbiotic bacteria had different reproductive patterns overall, but symbionts in general did not alter aphid reproduction in response to bacterial exposure. However, in response to exposure to alarm pheromone, aphids with Hamiltonella defensa or Serratia symbiotica symbiotic infections increased reproduction but those

  5. Cannibalism in the pea aphid, Acyrthosiphon pisum.

    PubMed

    Cooper, Lucy C; Desjonqueres, Camille; Leather, Simon R

    2014-12-01

    Previous observations of cannibalism have been made in the aphid Acyrthosiphon pisum (L.): this article seeks to quantify factors contributing to such behaviors. We observed and quantified the responses of a number of clones and life stages to varying levels of starvation, in the form of increasingly desiccated Vica faba L. plants (receiving 50, 25, or 10 mL every second day) or a complete absence of host plant. We found that, while the longest incidences of cannibalism are carried out by juveniles (F = 3.45, P = 0.019, df = 3) and targeted at adults, the starvation treatments had the most significant effect on the prevalence of cannibalism in mature A. pisum (F = 2.24, P = 0.025, df = 9). Furthermore, there was no difference between the prevalence or duration of cannibalistic activities within and between different clones (P ≥ 0.05 in all cases), though juveniles were more likely to target unrelated aphids (V = 6 112, P = 0.011), and spent more time feeding on aphids from the same culture (V = 6 062, P = 0.018).

  6. National Plant Diagnostic Network, Taxonomic training videos: Introduction to Aphids - Part 2

    USDA-ARS?s Scientific Manuscript database

    Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides visual instruction on important subject areas for aphid regulatory issues. Here the subject of aphids as they relate to disease transmission, biology, identification, and pathways is addressed. Aphid topi...

  7. Parasitism of aphids in canola fields in central Oklahoma

    USDA-ARS?s Scientific Manuscript database

    Winter canola, Brassica napus L., production in Oklahoma has increased from essentially 0 ha in 2001 to 40,500 ha in 2011, and acreage is expected to continue to increase. Three aphid species typically infest canola fields in central Oklahoma, the turnip aphid Lypaphis erysimi (Kaltenbach), the cab...

  8. Genome-wide association mapping of soybean aphid resistance traits

    USDA-ARS?s Scientific Manuscript database

    Soybean aphid is the most damaging insect pest of soybean in the Upper Midwest and is primarily controlled by insecticides. Soybean aphid resistance (i.e., Rag genes) has been documented in some soybean lines at chromosomes 6, 7, 13, and 16, but more sources of resistance are needed. Genome-wide ass...

  9. Genome sequence of the pea aphid Acyrthosiphon pisum.

    PubMed

    2010-02-23

    Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetabolous insect provides an outgroup to the multiple published genomes of holometabolous insects. Pea aphids are host-plant specialists, they can reproduce both sexually and asexually, and they have coevolved with an obligate bacterial symbiont. Here we highlight findings from whole genome analysis that may be related to these unusual biological features. These findings include discovery of extensive gene duplication in more than 2000 gene families as well as loss of evolutionarily conserved genes. Gene family expansions relative to other published genomes include genes involved in chromatin modification, miRNA synthesis, and sugar transport. Gene losses include genes central to the IMD immune pathway, selenoprotein utilization, purine salvage, and the entire urea cycle. The pea aphid genome reveals that only a limited number of genes have been acquired from bacteria; thus the reduced gene count of Buchnera does not reflect gene transfer to the host genome. The inventory of metabolic genes in the pea aphid genome suggests that there is extensive metabolite exchange between the aphid and Buchnera, including sharing of amino acid biosynthesis between the aphid and Buchnera. The pea aphid genome provides a foundation for post-genomic studies of fundamental biological questions and applied agricultural problems.

  10. Aggressive mimicry coexists with mutualism in an aphid.

    PubMed

    Salazar, Adrián; Fürstenau, Benjamin; Quero, Carmen; Pérez-Hidalgo, Nicolás; Carazo, Pau; Font, Enrique; Martínez-Torres, David

    2015-01-27

    Understanding the evolutionary transition from interspecific exploitation to cooperation is a major challenge in evolutionary biology. Ant-aphid relationships represent an ideal system to this end because they encompass a coevolutionary continuum of interactions ranging from mutualism to antagonism. In this study, we report an unprecedented interaction along this continuum: aggressive mimicry in aphids. We show that two morphs clonally produced by the aphid Paracletus cimiciformis during its root-dwelling phase establish relationships with ants at opposite sides of the mutualism-antagonism continuum. Although one of these morphs exhibits the conventional trophobiotic (mutualistic) relationship with ants of the genus Tetramorium, aphids of the alternative morph are transported by the ants to their brood chamber and cared for as if they were true ant larvae. Gas chromatography-mass spectrometry analyses reveal that the innate cuticular hydrocarbon profile of the mimic morph resembles the profile of ant larvae more than that of the alternative, genetically identical nonmimic morph. Furthermore, we show that, once in the brood chamber, mimic aphids suck on ant larva hemolymph. These results not only add aphids to the limited list of arthropods known to biosynthesize the cuticular chemicals of their deceived hosts to exploit their resources but describe a remarkable case of plastic aggressive mimicry. The present work adds a previously unidentified dimension to the classical textbook paradigm of aphid-ant relationships by showcasing a complex system at the evolutionary interface between cooperation and exploitation.

  11. Bird cherry-oat aphid resistance in barley

    USDA-ARS?s Scientific Manuscript database

    Bird cherry-oat aphid, Rhopalosiphum padi L., is a serious pest of barley, Hordeum vulgare L., world-wide. It is the most efficient vector of barley yellow dwarf virus, the most important viral disease of small grains in the world. Not all bird cherry-oat aphids acquire the virus while feeding on ...

  12. Genome Sequence of the Pea Aphid Acyrthosiphon pisum

    PubMed Central

    2010-01-01

    Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetabolous insect provides an outgroup to the multiple published genomes of holometabolous insects. Pea aphids are host-plant specialists, they can reproduce both sexually and asexually, and they have coevolved with an obligate bacterial symbiont. Here we highlight findings from whole genome analysis that may be related to these unusual biological features. These findings include discovery of extensive gene duplication in more than 2000 gene families as well as loss of evolutionarily conserved genes. Gene family expansions relative to other published genomes include genes involved in chromatin modification, miRNA synthesis, and sugar transport. Gene losses include genes central to the IMD immune pathway, selenoprotein utilization, purine salvage, and the entire urea cycle. The pea aphid genome reveals that only a limited number of genes have been acquired from bacteria; thus the reduced gene count of Buchnera does not reflect gene transfer to the host genome. The inventory of metabolic genes in the pea aphid genome suggests that there is extensive metabolite exchange between the aphid and Buchnera, including sharing of amino acid biosynthesis between the aphid and Buchnera. The pea aphid genome provides a foundation for post-genomic studies of fundamental biological questions and applied agricultural problems. PMID:20186266

  13. Efficacy of inorganic compounds against soybean aphid, laboratory tests 2012

    USDA-ARS?s Scientific Manuscript database

    Infestations by soybean aphids can reduce the yield of soybeans, and the efficacies of various compounds need evaluation for soybean aphid control. Efficacy of various inorganic compounds was compared to that of a water check and conventional insecticides in two growth-chamber tests. Soybean test ...

  14. Transcriptome profilng of defense responses to aphid feeding in wheat

    USDA-ARS?s Scientific Manuscript database

    Greenbug (Schizaphis graminum) is a serious aphid pest in small grain crops in the southern Great Plains of the US. We are trying to understand the molecular mechanisms of host resistance against aphid infestation in the grass genome using wheat-greenbug as a model system. In the present study, a mi...

  15. A New Soybean Aphid (Hemiptera: Aphididae) Biotype Identified

    USDA-ARS?s Scientific Manuscript database

    One of the greatest threats to soybean production in the main North American soybean production region continues to be the soybean aphid. An earlier study that identified a soybean aphid biotype that could colonize plants with the Rag1 resistance gene has raised concerns about the durability of soyb...

  16. Prey foraging by Hippodamia convergens for cereal aphids on wheat

    USDA-ARS?s Scientific Manuscript database

    We investigated predation by adult convergent lady beetle, Hippodamia convergens Guerin-Meneville, on English grain aphid, Sitobion avenae L., on wheat, Triticum aestivum L., plants in a laboratory arena, and developed a functional response model for the number of aphids eaten by an adult female con...

  17. Seasonal Abundance of Aphids and Aphidophagous Insects in Pecan

    PubMed Central

    Dutcher, James D.; Karar, Haider; Abbas, Ghulam

    2012-01-01

    Seasonal occurrence of aphids and aphidophagous insects was monitored for six years (2006–2011) from full leaf expansion in May to leaf fall in October in “Desirable” variety pecan trees that were not treated with insecticides. Aphid outbreaks occurred two times per season, once in the spring and again in the late summer. Yellow pecan and blackmargined aphids exceeded the recommended treatment thresholds one time and black pecan aphids exceeded the recommended treatment levels three times over the six seasons. Increases in aphidophagous insect abundance coincided with aphid outbreaks in five of the six seasons. Among aphidophagous insects Harmonia axyridis and Olla v-nigrum were frequently collected in both the tree canopy and at the ground level, whereas, Coccinella septempunctata, Hippodamia convergens were rarely found in the tree canopy and commonly found at the ground level. Green lacewing abundance was higher in the ground level than in the tree canopy. Brown lacewings were more abundant in the tree canopy than at the ground level. Dolichopodid and syrphid fly abundance, at the ground level increased during peak aphid abundance in the tree canopy. Application of an aqueous solution of fermenting molasses to the pecan foliage during an aphid outbreak significantly increased the abundance of ladybeetles and lacewings and significantly reduced the abundance of yellow pecan, blackmargined and black pecan aphids. PMID:26466738

  18. Detection of novel QTLs for foxglove aphid resistance in soybean

    USDA-ARS?s Scientific Manuscript database

    Foxglove aphid, Aulacorthum solani (Kaltenbach), is a Hemipteran insect that infected a wide variety of plants worldwide and caused serious yield losses in crops. The objective of this study was to identify the putative QTL for foxglove aphid resistance in wild soybean, PI 366121, (Glycine soja Sieb...

  19. Genetic studies on sugarcane aphid resistance in sorghum

    USDA-ARS?s Scientific Manuscript database

    In the southern United States, the white sugarcane aphid (Melanaphis sacchari) has recently become a major pest of sorghum. The aphid population can build up rapidly on the undersides of sorghum leaves causing leaf damage, leaf death, stunting, delayed flowering, and plant death. Furthermore, the ov...

  20. NDVI to detect sugarcane aphid injury to grain sorghum

    USDA-ARS?s Scientific Manuscript database

    Multispectral remote sensing has potential to provide quick and inexpensive information on sugarcane aphid, Melanaphis sacchari (Zehntner), pest status in sorghum fields. The purpose of this report is to describe a study conducted to determine if injury caused by sugarcane aphid to sorghum plants i...

  1. Soybean Aphid (Hemiptera: Aphididae) Affects Soybean Spectral Reflectance

    PubMed Central

    Alves, Tavvs M.; Macrae, Ian V.; Koch, Robert L.

    2015-01-01

    Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is the most economically important insect pest of soybean in the north central United States. Scouting-based integrated pest management (IPM) programs could become more efficient and more widely adopted by using plant spectral reflectance to estimate soybean aphid injury. Our objective was to determine whether plant spectral reflectance is affected by soybean aphid feeding. Field trials were conducted in 2013 and 2014 using caged plots. Early-, late-, and noninfested treatments were established to create a gradient of soybean aphid pressure. Whole-plant soybean aphid densities were recorded weekly. Measurements of plant spectral reflectance occurred on two sample dates per year. Simple linear regression models were used to test the effect of cumulative aphid-days (CAD) on plant spectral reflectance at 680 nm (RED) and 800 nm (NIR), normalized difference vegetation index (NDVI), and relative chlorophyll content. Data indicated that CAD had no effect on canopy-level RED reflectance, but CAD decreased canopy-level NIR reflectance and NDVI. Canopy- and leaf-level measurements typically indicated similar plant spectral response to increasing CAD. CAD generally had no effect on relative chlorophyll content. The present study provides the first documentation that remote sensing holds potential for detecting changes in plant spectral reflectance induced by soybean aphid. The use of plant spectral reflectance in soybean aphid management may assist future IPM programs to reduce sampling costs and prevent prophylactic insecticide sprays. PMID:26470392

  2. Seasonal Abundance of Aphids and Aphidophagous Insects in Pecan.

    PubMed

    Dutcher, James D; Karar, Haider; Abbas, Ghulam

    2012-12-05

    Seasonal occurrence of aphids and aphidophagous insects was monitored for six years (2006-2011) from full leaf expansion in May to leaf fall in October in "Desirable" variety pecan trees that were not treated with insecticides. Aphid outbreaks occurred two times per season, once in the spring and again in the late summer. Yellow pecan and blackmargined aphids exceeded the recommended treatment thresholds one time and black pecan aphids exceeded the recommended treatment levels three times over the six seasons. Increases in aphidophagous insect abundance coincided with aphid outbreaks in five of the six seasons. Among aphidophagous insects Harmonia axyridis and Olla v-nigrum were frequently collected in both the tree canopy and at the ground level, whereas, Coccinella septempunctata, Hippodamia convergens were rarely found in the tree canopy and commonly found at the ground level. Green lacewing abundance was higher in the ground level than in the tree canopy. Brown lacewings were more abundant in the tree canopy than at the ground level. Dolichopodid and syrphid fly abundance, at the ground level increased during peak aphid abundance in the tree canopy. Application of an aqueous solution of fermenting molasses to the pecan foliage during an aphid outbreak significantly increased the abundance of ladybeetles and lacewings and significantly reduced the abundance of yellow pecan, blackmargined and black pecan aphids.

  3. New Plant Introductions with Resistance to the Soybean Aphid

    USDA-ARS?s Scientific Manuscript database

    The soybean aphid (Aphis glycines Matsumura) (SA) was first found in the northern soybean, Glycine max (L.) Merr., growing regions of the USA in 2000. By 2005, the aphid had spread to 23 soybean growing states reaching as far south as Mississippi and Georgia and also north into Ontario, Canada. Th...

  4. Population genetic structure of the soybean aphid, Aphis glycines

    USDA-ARS?s Scientific Manuscript database

    The soybean aphid (Aphis glycines Matsumura) is an invasive pest of cultivated soybean [Glycine max (L.)] in North America. After the initial invasion in 2000, the aphid has quickly spread across most of the U.S. and Canada, suggesting large scale dispersals and rapid adaptations to new environment...

  5. Breeding for resistance to the sugarcane aphid [Melanaphis sacchari (Zehntner)

    USDA-ARS?s Scientific Manuscript database

    The sugarcane aphid [Melanaphis sacchari] (SCA) was first reported to damage sorghum [Sorghum bicolor (L.) Moench] in the United States in Louisiana and Texas in 2013, and was subsequently detected in Oklahoma and the Mississippi Delta. In 2014, the aphid spread and was eventually reported in state...

  6. Host plant selection by aphids: behavioral, evolutionary, and applied perspectives.

    PubMed

    Powell, Glen; Tosh, Colin R; Hardie, Jim

    2006-01-01

    As phloem feeders and major vectors of plant viruses, aphids are important pests of agricultural and horticultural crops worldwide. The processes of aphid settling and reproduction on plants therefore have a direct economic impact, and a better understanding of these events may lead to improved management strategies. Aphids are also important model organisms in the analysis of population differentiation and speciation in animals, and new ideas on plant utilization influence our understanding of the mechanisms generating biological diversity. Recent research suggests that the dominant cues controlling plant preference and initiation of reproduction are detected early during the stylet penetration process, well before the nutrient supply (phloem) is contacted. Aphids regularly puncture cells along the stylet pathway and ingest cytosolic samples, and the cues stimulating settling and parturition likely are metabolites present in peripheral (nonvascular) plant cells. We discuss these findings and their implications for aphid evolution and management.

  7. Chlorotic feeding injury by the black pecan aphid (hemiptera: aphididae) to pecan foliage promotes aphid settling and nymphal development.

    PubMed

    Cottrell, Ted E; Wood, Bruce W; Ni, Xinzhi

    2009-04-01

    The nature of the interaction between the black pecan aphid, Melanocallis caryaefoliae (Davis) (Hemiptera: Aphididae), and the chlorosis it causes to foliage of its pecan [Carya illinoinensis (Wangenh.) K. Koch)] host is poorly understood. Laboratory experiments were conducted on the settling behavior of the black pecan aphid, when provided chlorotic pecan leaf discs resulting from previous black pecan aphid feeding and nonchlorotic leaf discs, under a normal photoperiod and constant dark. Additionally, aphid development from the first instar to the adult stage was examined when nymphs were either allowed to feed on the same leaf disc or moved daily to a new, nondamaged, same age leaf disc. After 24 h, a significantly higher percentage of black pecan aphids settled on chlorotic than on nonchlorotic leaf discs, regardless of photoperiod. When starting from the first instar, nymphs that were prevented from inducing leaf chlorosis by moving daily to new, same-age leaf discs took approximately 5 d longer to complete development, had a shorter body length, and had higher mortality than when aphids remained on the same leaf disc. These results show that black pecan aphid-induced leaf chlorosis plays an important role in the interaction of the black pecan aphid with its pecan host.

  8. In planta expression or delivery of potato aphid Macrosiphum euphorbiae effectors Me10 and Me23 enhances aphid fecundity.

    PubMed

    Atamian, Hagop S; Chaudhary, Ritu; Cin, Valeriano Dal; Bao, Ergude; Girke, Thomas; Kaloshian, Isgouhi

    2013-01-01

    The interactions between aphids and their host plants seem to be analogous to those of plant-microbial pathogens. Unlike microbial pathogen effectors, little is known about aphid effectors and their ability to interfere with host immunity. To date, only three functional aphid effectors have been reported. To identify potato aphid (Macrosiphum euphorbiae) effectors, we developed a salivary gland transcriptome using Illumina technology. We generated 85 million Illumina reads from salivary glands and assembled them into 646 contigs. Ab initio sequence analysis predicted secretion signal peptides in 24% of these sequences, suggesting that they might be secreted into the plant during aphid feeding. Eight of these candidate effectors with secretion signal peptides were functionally characterized using Agrobacterium tumefaciens-mediated transient overexpression in Nicotiana benthamiana. Two candidate effectors, Me10 and Me23, increased aphid fecundity, suggesting their ability to suppress N. benthamiana defenses. Five of these candidate effectors, including Me10 and Me23, were also analyzed in tomato by delivering them through the Pseudomonas syringae type three secretion system. In tomato, only Me10 increased aphid fecundity. This work identified two additional aphid effectors with ability to manipulate the host for their advantage.

  9. Parasitic wasp responses to symbiont-based defense in aphids

    PubMed Central

    2012-01-01

    Background Recent findings indicate that several insect lineages receive protection against particular natural enemies through infection with heritable symbionts, but little is yet known about whether enemies are able to discriminate and respond to symbiont-based defense. The pea aphid, Acyrthosiphon pisum, receives protection against the parasitic wasp, Aphidius ervi, when infected with the bacterial symbiont Hamiltonella defensa and its associated bacteriophage APSE (Acyrthosiphon pisum secondary endosymbiont). Internally developing parasitoid wasps, such as A. ervi, use maternal and embryonic factors to create an environment suitable for developing wasps. If more than one parasitoid egg is deposited into a single aphid host (superparasitism), then additional complements of these factors may contribute to the successful development of the single parasitoid that emerges. Results We performed experiments to determine if superparasitism is a tactic allowing wasps to overcome symbiont-mediated defense. We found that the deposition of two eggs into symbiont-protected aphids significantly increased rates of successful parasitism relative to singly parasitized aphids. We then conducted behavioral assays to determine whether A. ervi selectively superparasitizes H. defensa-infected aphids. In choice tests, we found that A. ervi tends to deposit a single egg in uninfected aphids, but two or more eggs in H. defensa-infected aphids, indicating that oviposition choices may be largely determined by infection status. Finally, we identified differences in the quantity of the trans-β-farnesene, the major component of aphid alarm pheromone, between H. defensa-infected and uninfected aphids, which may form the basis for discrimination. Conclusions Here we show that the parasitic wasp A. ervi discriminates among symbiont-infected and uninfected aphids, and changes its oviposition behavior in a way that increases the likelihood of overcoming symbiont-based defense. More generally

  10. Parasitic wasp responses to symbiont-based defense in aphids.

    PubMed

    Oliver, Kerry M; Noge, Koji; Huang, Emma M; Campos, Jaime M; Becerra, Judith X; Hunter, Martha S

    2012-02-24

    Recent findings indicate that several insect lineages receive protection against particular natural enemies through infection with heritable symbionts, but little is yet known about whether enemies are able to discriminate and respond to symbiont-based defense. The pea aphid, Acyrthosiphon pisum, receives protection against the parasitic wasp, Aphidius ervi, when infected with the bacterial symbiont Hamiltonella defensa and its associated bacteriophage APSE (Acyrthosiphon pisum secondary endosymbiont). Internally developing parasitoid wasps, such as A. ervi, use maternal and embryonic factors to create an environment suitable for developing wasps. If more than one parasitoid egg is deposited into a single aphid host (superparasitism), then additional complements of these factors may contribute to the successful development of the single parasitoid that emerges. We performed experiments to determine if superparasitism is a tactic allowing wasps to overcome symbiont-mediated defense. We found that the deposition of two eggs into symbiont-protected aphids significantly increased rates of successful parasitism relative to singly parasitized aphids. We then conducted behavioral assays to determine whether A. ervi selectively superparasitizes H. defensa-infected aphids. In choice tests, we found that A. ervi tends to deposit a single egg in uninfected aphids, but two or more eggs in H. defensa-infected aphids, indicating that oviposition choices may be largely determined by infection status. Finally, we identified differences in the quantity of the trans-β-farnesene, the major component of aphid alarm pheromone, between H. defensa-infected and uninfected aphids, which may form the basis for discrimination. Here we show that the parasitic wasp A. ervi discriminates among symbiont-infected and uninfected aphids, and changes its oviposition behavior in a way that increases the likelihood of overcoming symbiont-based defense. More generally, our results indicate that

  11. Distribution of the black pecan aphid, Melanocallis caryaefoliae, on the upper and lower surface of pecan foliage

    USDA-ARS?s Scientific Manuscript database

    Three aphid species regularly feed on the foliage of pecan: the black pecan aphid Melanocallis caryaefoliae (Davis), the yellow pecan aphid Monelliopsis pecanis (Davis), and the blackmargined aphid Monellia caryella (Fitch). The black pecan aphid appears unique among these for frequently being obser...

  12. Evaluation of the susceptibility of the pea aphid, Acyrthosiphon pisum, to a selection of novel biorational insecticides using an artificial diet.

    PubMed

    Sadeghi, Amin; Van Damme, Els J M; Smagghe, Guy

    2009-01-01

    An improved technique was developed to assay the toxicity of insecticides against aphids using an artificial diet. The susceptibility of the pea aphid Acyrthosiphon pisum (Harris) (Hemiptera: Aphidoidea) was determined for a selection of novel biorational insecticides, each representing a novel mode of action. Flonicamid, a novel systemic insecticide with selective activity as feeding blocker against sucking insects, showed high toxicity against first-instar A. pisum nymphs with an LC(50) of 20.4 microg/ml after 24 h, and of 0.24 microg/ml after 72 h. The toxicity was compared with another feeding blocker, pymetrozine, and the neonicotinoid, imidacloprid. In addition, four insect growth regulators were tested. The chitin synthesis inhibitor flufenoxuron, the juvenile hormone analogue pyriproxyfen, and the azadirachtin compound Neem Azal-T/S showed strong effects and reduced the aphid population by 50% after 3 days of treatment at a concentration of 7-9 microg/ml. The ecdysone agonist tested, halofenozide, was less potent. In conclusion, the improved aphid feeding apparatus can be useful as a miniature screening device for insecticides against different aphid pests. The present study demonstrated rapid and strong toxicity of flonicamid, and other biorational insecticides towards A. pisum.

  13. Evaluation of the Susceptibility of the Pea Aphid, Acyrthosiphon pisum, to a Selection of Novel Biorational Insecticides using an Artificial Diet

    PubMed Central

    Sadeghi, Amin; Van Damme, Els J.M.; Smagghe, Guy

    2009-01-01

    An improved technique was developed to assay the toxicity of insecticides against aphids using an artificial diet. The susceptibility of the pea aphid Acyrthosiphon pisum (Harris) (Hemiptera: Aphidoidea) was determined for a selection of novel biorational insecticides, each representing a novel mode of action. Flonicamid, a novel systemic insecticide with selective activity as feeding blocker against sucking insects, showed high toxicity against first-instar A. pisum nymphs with an LC50 of 20.4 μg/ml after 24 h, and of 0.24 µg/ml after 72 h. The toxicity was compared with another feeding blocker, pymetrozine, and the neonicotinoid, imidacloprid. In addition, four insect growth regulators were tested. The chitin synthesis inhibitor flufenoxuron, the juvenile hormone analogue pyriproxyfen, and the azadirachtin compound Neem Azal-T/S showed strong effects and reduced the aphid population by 50% after 3 days of treatment at a concentration of 7–9 µg/ml. The ecdysone agonist tested, halofenozide, was less potent. In conclusion, the improved aphid feeding apparatus can be useful as a miniature screening device for insecticides against different aphid pests. The present study demonstrated rapid and strong toxicity of flonicamid, and other biorational insecticides towards A. pisum. PMID:20053120

  14. Multiple Cues for Winged Morph Production in an Aphid Metacommunity

    PubMed Central

    Mehrparvar, Mohsen; Zytynska, Sharon E.; Weisser, Wolfgang W.

    2013-01-01

    Environmental factors can lead individuals down different developmental pathways giving rise to distinct phenotypes (phenotypic plasticity). The production of winged or unwinged morphs in aphids is an example of two alternative developmental pathways. Dispersal is paramount in aphids that often have a metapopulation structure, where local subpopulations frequently go extinct, such as the specialized aphids on tansy (Tanacetum vulgare). We conducted various experiments to further understand the cues involved in the production of winged dispersal morphs by the two dominant species of the tansy aphid metacommunity, Metopeurum fuscoviride and Macrosiphoniella tanacetaria. We found that the ant-tended M. fuscoviride produced winged individuals predominantly at the beginning of the season while the untended M. tanacetaria produced winged individuals throughout the season. Winged mothers of both species produced winged offspring, although in both species winged offspring were mainly produced by unwinged females. Crowding and the presence of predators, effects already known to influence wing production in other aphid species, increased the percentage of winged offspring in M. tanacetaria, but not in M. fuscoviride. We find there are also other factors (i.e. temporal effects) inducing the production of winged offspring for natural aphid populations. Our results show that the responses of each aphid species are due to multiple wing induction cues. PMID:23472179

  15. Aphids (Hemiptera, Aphididae) on ornamental plants in greenhouses in Bulgaria

    PubMed Central

    Yovkova, Mariya; Petrović-Obradović, Olivera; Tasheva-Terzieva, Elena; Pencheva, Aneliya

    2013-01-01

    Abstract Investigations on the species composition and host range of aphids on ornamental greenhouse plants in Bulgaria was conducted over a period of five years, from 2008 to 2012. Twenty greenhouses, growing ornamentals for landscaping, plant collections and other purposes were observed. They were located in the regions of Sofia, Plovdiv, Smolyan, Pavlikeni, Varna and Burgas. The total number of collected aphid samples was 279. Their composition included 33 aphid species and one subspecies from 13 genera and 5 subfamilies. Twenty-eight species were found to belong to subfamily Aphidinae. Almost 70 % of all recorded species were polyphagous. The most widespread aphid species was Myzus persicae, detected in 13 greenhouses all year round, followed by Aulacorthum solani (10 greenhouses) and Aphis gossypii (9 greenhouses). The widest host range was shown by Myzus persicae (43 hosts), Aulacorthum solani (32 hosts) and Aulacorthum circumflexum (23 hosts). The list of host plants includes 114 species from 95 genera and 58 families. The greatest variety of aphid species was detected on Hibiscus (9 species). Out of all aphid samples 12.9 % were collected on Hibiscus and 6.8 %, on Dendranthema. The greatest variety of aphid species was detected on Hibiscus (9 species). Periphyllus californiensis and Aphis (Aphis) fabae mordvilkoi are reported for the first time for Bulgaria. Furthermore, Aphis spiraecola has been found in new localities and has widened its host range in this country. PMID:24039530

  16. Aphids (Hemiptera, Aphididae) on ornamental plants in greenhouses in Bulgaria.

    PubMed

    Yovkova, Mariya; Petrović-Obradović, Olivera; Tasheva-Terzieva, Elena; Pencheva, Aneliya

    2013-01-01

    Investigations on the species composition and host range of aphids on ornamental greenhouse plants in Bulgaria was conducted over a period of five years, from 2008 to 2012. Twenty greenhouses, growing ornamentals for landscaping, plant collections and other purposes were observed. They were located in the regions of Sofia, Plovdiv, Smolyan, Pavlikeni, Varna and Burgas. The total number of collected aphid samples was 279. Their composition included 33 aphid species and one subspecies from 13 genera and 5 subfamilies. Twenty-eight species were found to belong to subfamily Aphidinae. Almost 70 % of all recorded species were polyphagous. The most widespread aphid species was Myzus persicae, detected in 13 greenhouses all year round, followed by Aulacorthum solani (10 greenhouses) and Aphis gossypii (9 greenhouses). The widest host range was shown by Myzus persicae (43 hosts), Aulacorthum solani (32 hosts) and Aulacorthum circumflexum (23 hosts). The list of host plants includes 114 species from 95 genera and 58 families. The greatest variety of aphid species was detected on Hibiscus (9 species). Out of all aphid samples 12.9 % were collected on Hibiscus and 6.8 %, on Dendranthema. The greatest variety of aphid species was detected on Hibiscus (9 species). Periphyllus californiensis and Aphis (Aphis) fabae mordvilkoi are reported for the first time for Bulgaria. Furthermore, Aphis spiraecola has been found in new localities and has widened its host range in this country.

  17. Faba bean forisomes can function in defence against generalist aphids.

    PubMed

    Medina-Ortega, Karla J; Walker, Gregory P

    2015-06-01

    Phloem sieve elements have shut-off mechanisms that prevent loss of nutrient-rich phloem sap when the phloem is damaged. Some phloem proteins such as the proteins that form forisomes in legume sieve elements are one such mechanism and in response to damage, they instantly form occlusions that stop the flow of sap. It has long been hypothesized that one function of phloem proteins is defence against phloem sap-feeding insects such as aphids. This study provides the first experimental evidence that aphid feeding can induce phloem protein occlusion and that the aphid-induced occlusions inhibit phloem sap ingestion. The great majority of phloem penetrations in Vicia faba by the generalist aphids Myzus persicae and Macrosiphum euphorbiae triggered forisome occlusion and the aphids eventually withdrew their stylets without ingesting phloem sap. This contrasts starkly with a previous study on the legume-specialist aphid, Acyrthosiphon pisum, where penetration of faba bean sieve elements did not trigger forisome occlusion and the aphids readily ingested phloem sap. Next, forisome occlusion was demonstrated to be the cause of failed phloem ingestion attempts by M. persicae: when occlusion was inhibited by the calcium channel blocker lanthanum, M. persicae readily ingested faba bean phloem sap.

  18. Native aphids of New Zealand--diversity and host associations.

    PubMed

    Teulon, D A J; Stufkens, M A W; Drayton, G M; Maw, H E L; Scott, I A W; Bulman, S R; Carver, M; Von Dohlen, C D; Eastop, V F; Foottit, R G

    2013-01-01

    At least 15 species of aphids are now recognised as New Zealand natives and most of these are very likely to be endemic. Most native aphids belong in the subfamily Aphidinae (Aphidini), with a possible single species in Aphidinae-Macrosiphini, at least two in Neophyllaphidinae and one in Taiwanaphidinae. With one exception, native aphids are restricted to a single host plant genus, and these hosts are from 13 genera and 12 plant families in the Pinales and Angiospermae-Eudicotyledonae, suggesting that the aphids are a remnant fauna. No known native aphids have host plants from the Pteridophyta or Angiospermae-Monocotyledonae, with the possible exception of two possibly native species extracted from native tussock grassland turfs. Most host plant genera have some degree of Gondwanan distribution, but only two indigenous species are found on large forest trees and only one host is deciduous. Native aphids have been recorded from sea level to the subalpine zone, reflecting their host plant distributions. Sexual reproduction, followed by several parthenogenetic generations on the same host plant, appears to be the norm for most species. Eggs appear to be used for surviving winter conditions in some species and summer conditions in others. Native aphid distribution and abundance varies with five species considered to be scarce, one species localised, two species sparse and three relatively common based on current knowledge.

  19. Plant stomatal closure improves aphid feeding under elevated CO2.

    PubMed

    Sun, Yucheng; Guo, Huijuan; Yuan, Liang; Wei, Jianing; Zhang, Wenhao; Ge, Feng

    2015-01-10

    Stomata help plants regulate CO2 absorption and water vapor release in response to various environmental changes, and plants decrease their stomatal apertures and enhance their water status under elevated CO2 . Although the bottom-up effect of elevated CO2 on insect performance has been extensively studied, few reports have considered how insect fitness is altered by elevated CO2 -induced changes in host plant water status. We tested the hypothesis that aphids induce stomatal closure and increase host water potential, which facilitates their passive feeding, and that this induction can be enhanced by elevated CO2 . Our results showed that aphid infestation triggered the abscisic acid (ABA) signaling pathway to decrease the stomatal apertures of Medicago truncatula, which consequently decreased leaf transpiration and helped maintain leaf water potential. These effects increased xylem-feeding time and decreased hemolymph osmolarity, which thereby enhanced phloem-feeding time and increased aphid abundance. Furthermore, elevated CO2 up-regulated an ABA-independent enzyme, carbonic anhydrase, which led to further decrease in stomatal aperture for aphid-infested plants. Thus, the effects of elevated CO2 and aphid infestation on stomatal closure synergistically improved the water status of the host plant. The results indicate that aphid infestation enhances aphid feeding under ambient CO2 and that this enhancement is increased under elevated CO2 . © 2015 John Wiley & Sons Ltd.

  20. Color polymorphism in an aphid is maintained by attending ants

    PubMed Central

    Watanabe, Saori; Murakami, Taiga; Yoshimura, Jin; Hasegawa, Eisuke

    2016-01-01

    The study of polymorphisms is particularly informative for enhancing our understanding of phenotypic and genetic diversity. The persistence of polymorphism in a population is generally explained by balancing selection. Color polymorphisms that are often found in many insects and arthropods are prime examples of the maintenance of polymorphisms via balancing selection. In some aphids, color morphs are maintained through frequency-dependent predation by two predatory insects. However, the presence of color polymorphism in ant-attended aphids cannot be explained by traditional balancing selection because these aphids are free from predation. We examined the selective advantages of the existence of two color (red and green) morphs in the ant-attended aphid, Macrosiphoniella yomogicola, in fields. We measured the degree of ant attendance on aphid colonies with different proportions of color morphs. The results show that the ants strongly favor aphid colonies with intermediate proportions of the two color morphs. The relationship between the degree of ant attendance and the proportion of color morphs in the field is convex when aphid colony size and ant colony size are controlled. This function has a peak of approximately 65% of green morphs in a colony. This system represents the first case of a balancing polymorphism that is not maintained by opposing factors but by a symbiotic relationship. PMID:27617289

  1. Conserved Odorant-Binding Proteins from Aphids and Eavesdropping Predators

    PubMed Central

    Vandermoten, Sophie; Francis, Frédéric; Haubruge, Eric; Leal, Walter S.

    2011-01-01

    Background The sesquiterpene (E)-ß-farnesene is the main component of the alarm pheromone system of various aphid species studied to date, including the English grain aphid, Sitobion avenae. Aphid natural enemies, such as the marmalade hoverfly Episyrphus balteatus and the multicolored Asian lady beetle Harmonia axyridis, eavesdrop on aphid chemical communication and utilize (E)-ß-farnesene as a kairomone to localize their immediate or offspring preys. These aphid-predator systems are important models to study how the olfactory systems of distant insect taxa process the same chemical signal. We postulated that odorant-binding proteins (OBPs), which are highly expressed in insect olfactory tissues and involved in the first step of odorant reception, have conserved regions involved in binding (E)-ß-farnesene. Methodology We cloned OBP genes from the English grain aphid and two major predators of this aphid species. We then expressed these proteins and compare their binding affinities to the alarm pheromone/kairomone. By using a fluorescence reporter, we tested binding of (E)-ß-farnesene and other electrophysiologically and behaviorally active compounds, including a green leaf volatile attractant. Conclusion We found that OBPs from disparate taxa of aphids and their predators are highly conserved proteins, with apparently no orthologue genes in other insect species. Properly folded, recombinant proteins from the English grain aphid, SaveOBP3, and the marmalade hoverfly, EbalOBP3, specifically bind (E)-ß-farnesene with apparent high affinity. For the first time we have demonstrated that insect species belonging to distinct Orders have conserved OBPs, which specifically bind a common semiochemical and has no binding affinity for related compounds. PMID:21912599

  2. Social Aggregation in Pea Aphids: Experiment and Random Walk Modeling

    PubMed Central

    Nilsen, Christa; Paige, John; Warner, Olivia; Mayhew, Benjamin; Sutley, Ryan; Lam, Matthew; Bernoff, Andrew J.; Topaz, Chad M.

    2013-01-01

    From bird flocks to fish schools and ungulate herds to insect swarms, social biological aggregations are found across the natural world. An ongoing challenge in the mathematical modeling of aggregations is to strengthen the connection between models and biological data by quantifying the rules that individuals follow. We model aggregation of the pea aphid, Acyrthosiphon pisum. Specifically, we conduct experiments to track the motion of aphids walking in a featureless circular arena in order to deduce individual-level rules. We observe that each aphid transitions stochastically between a moving and a stationary state. Moving aphids follow a correlated random walk. The probabilities of motion state transitions, as well as the random walk parameters, depend strongly on distance to an aphid's nearest neighbor. For large nearest neighbor distances, when an aphid is essentially isolated, its motion is ballistic with aphids moving faster, turning less, and being less likely to stop. In contrast, for short nearest neighbor distances, aphids move more slowly, turn more, and are more likely to become stationary; this behavior constitutes an aggregation mechanism. From the experimental data, we estimate the state transition probabilities and correlated random walk parameters as a function of nearest neighbor distance. With the individual-level model established, we assess whether it reproduces the macroscopic patterns of movement at the group level. To do so, we consider three distributions, namely distance to nearest neighbor, angle to nearest neighbor, and percentage of population moving at any given time. For each of these three distributions, we compare our experimental data to the output of numerical simulations of our nearest neighbor model, and of a control model in which aphids do not interact socially. Our stochastic, social nearest neighbor model reproduces salient features of the experimental data that are not captured by the control. PMID:24376691

  3. Social aggregation in pea aphids: experiment and random walk modeling.

    PubMed

    Nilsen, Christa; Paige, John; Warner, Olivia; Mayhew, Benjamin; Sutley, Ryan; Lam, Matthew; Bernoff, Andrew J; Topaz, Chad M

    2013-01-01

    From bird flocks to fish schools and ungulate herds to insect swarms, social biological aggregations are found across the natural world. An ongoing challenge in the mathematical modeling of aggregations is to strengthen the connection between models and biological data by quantifying the rules that individuals follow. We model aggregation of the pea aphid, Acyrthosiphon pisum. Specifically, we conduct experiments to track the motion of aphids walking in a featureless circular arena in order to deduce individual-level rules. We observe that each aphid transitions stochastically between a moving and a stationary state. Moving aphids follow a correlated random walk. The probabilities of motion state transitions, as well as the random walk parameters, depend strongly on distance to an aphid's nearest neighbor. For large nearest neighbor distances, when an aphid is essentially isolated, its motion is ballistic with aphids moving faster, turning less, and being less likely to stop. In contrast, for short nearest neighbor distances, aphids move more slowly, turn more, and are more likely to become stationary; this behavior constitutes an aggregation mechanism. From the experimental data, we estimate the state transition probabilities and correlated random walk parameters as a function of nearest neighbor distance. With the individual-level model established, we assess whether it reproduces the macroscopic patterns of movement at the group level. To do so, we consider three distributions, namely distance to nearest neighbor, angle to nearest neighbor, and percentage of population moving at any given time. For each of these three distributions, we compare our experimental data to the output of numerical simulations of our nearest neighbor model, and of a control model in which aphids do not interact socially. Our stochastic, social nearest neighbor model reproduces salient features of the experimental data that are not captured by the control.

  4. Bacterial communities of two parthenogenetic aphid species cocolonizing two host plants across the Hawaiian Islands.

    PubMed

    Jones, Ryan T; Bressan, Alberto; Greenwell, April M; Fierer, Noah

    2011-12-01

    Aphids (Hemiptera: Aphididae) have been the focus of several studies with respect to their interactions with inherited symbionts, but bacterial communities of most aphid species are still poorly characterized. In this research, we used bar-coded pyrosequencing to characterize bacterial communities in aphids. Specifically, we examined the diversity of bacteria in two obligately parthenogenetic aphid species (the melon aphid, Aphis gossypii, and the cardamom aphid, Pentalonia caladii) cocolonizing two plant species (taro, Colocasia esculenta, and ginger, Alpinia purpurata) across four Hawaiian Islands (Hawaii, Kauai, Maui, and Oahu). Results from this study revealed that heritable symbionts dominated the bacterial communities for both aphid species. The bacterial communities differed significantly between the two species, and A. gossypii harbored a more diverse bacterial community than P. caladii. The bacterial communities also differed across aphid populations sampled from the different islands; however, communities did not differ between aphids collected from the two host plants.

  5. Bacterial Communities of Two Parthenogenetic Aphid Species Cocolonizing Two Host Plants across the Hawaiian Islands ▿

    PubMed Central

    Jones, Ryan T.; Bressan, Alberto; Greenwell, April M.; Fierer, Noah

    2011-01-01

    Aphids (Hemiptera: Aphididae) have been the focus of several studies with respect to their interactions with inherited symbionts, but bacterial communities of most aphid species are still poorly characterized. In this research, we used bar-coded pyrosequencing to characterize bacterial communities in aphids. Specifically, we examined the diversity of bacteria in two obligately parthenogenetic aphid species (the melon aphid, Aphis gossypii, and the cardamom aphid, Pentalonia caladii) cocolonizing two plant species (taro, Colocasia esculenta, and ginger, Alpinia purpurata) across four Hawaiian Islands (Hawaii, Kauai, Maui, and Oahu). Results from this study revealed that heritable symbionts dominated the bacterial communities for both aphid species. The bacterial communities differed significantly between the two species, and A. gossypii harbored a more diverse bacterial community than P. caladii. The bacterial communities also differed across aphid populations sampled from the different islands; however, communities did not differ between aphids collected from the two host plants. PMID:21965398

  6. Establishment of in vitro soybean aphids, Aphis glycines (Hemiptera: Aphididae): a tool to facilitate studies of aphid symbionts, plant-insect interactions and insecticide efficacy.

    PubMed

    Gunadi, Andika; Bansal, Raman; Finer, John J; Michel, Andy

    2017-06-01

    Studies on plant-insect interactions of the soybean aphid, Aphis glycines (Matsumura), can be influenced by environmental fluctuations, status of the host plant and variability in microbial populations. Maintenance of aphids on in vitro-grown plants minimizes environmental fluctuations, provides uniform host materials and permits the selective elimination of aphid-associated microbes for more standardized controls in aphid research. Aphids were reared on sterile, in vitro-grown soybean seedlings germinated on plant tissue culture media amended with a mixture of antimicrobials. For initiation and maintenance of in vitro aphid colonies, single aphids were inoculated onto single in vitro seedlings. After three rounds of transfer of 'clean' aphids to fresh in vitro seedlings, contamination was no longer observed, and aphids performed equally well when compared with those reared on detached leaves. The addition of the insecticides thiamethoxam and chlorantraniliprole to the culture medium confirmed uptake and caused significant mortality to the in vitro aphids. The use of the antimicrobial mixture removed the associated bacteria Arsenophonus but retained Buchnera and Wolbachia within the in vitro aphids. The in vitro aphid system is a novel and highly useful tool to understand insecticidal efficacy and expand our knowledge of tritrophic interactions among plants, insects and symbionts. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  7. Impact of Rag1 aphid resistant soybeans on Binodoxys communis (Hymenoptera: Braconidae), a parasitoid of soybean aphid (Hemiptera: Aphididae).

    PubMed

    Ghising, Kiran; Harmon, Jason P; Beauzay, Patrick B; Prischmann-Voldseth, Deirdre A; Helms, Ted C; Ode, Paul J; Knodel, Janet J

    2012-04-01

    Multiple strategies are being developed for pest management of the soybean aphid, Aphis glycines Matsumura; however, there has been little published research thus far to determine how such strategies may influence each other, thereby complicating their potential effectiveness. A susceptible soybean (Glycine max L.) variety without the Rag1 gene and a near isogenic resistant soybean variety with the Rag1 gene were evaluated in the laboratory for their effects on the fitness of the soybean aphid parasitoid, Binodoxys communis (Gahan). The presence or absence of the Rag1 gene was verified by quantifying soybean aphid growth. To test for fitness effects, parasitoids were allowed to attack soybean aphids on either a susceptible or resistant plant for 24 h and then aphids were kept on the same plant throughout parasitoid development. Parasitoid fitness was measured by mummy and adult parasitoid production, adult parasitoid emergence, development time, and adult size. Parasitoids that attacked soybean aphids on susceptible plants produced more mummies, more adult parasitoids, and had a higher emergence rate compared with those on resistant plants. Adult parasitoids that emerged from resistant plants took 1 d longer and were smaller compared with those from susceptible plants. This study suggests that biological control by B. communis may be compromised when host plant resistance is widely used for pest management of soybean aphids.

  8. Escherichia coli K-12 pathogenicity in the pea aphid, Acyrthosiphon pisum, reveals reduced antibacterial defense in aphids.

    PubMed

    Altincicek, Boran; Ter Braak, Bas; Laughton, Alice M; Udekwu, Klas I; Gerardo, Nicole M

    2011-10-01

    To better understand the molecular basis underlying aphid immune tolerance to beneficial bacteria and immune defense to pathogenic bacteria, we characterized how the pea aphid Acyrthosiphon pisum responds to Escherichia coli K-12 infections. E. coli bacteria, usually cleared in the hemolymph of other insect species, were capable of growing exponentially and killing aphids within a few days. Red fluorescence protein expressing E. coli K-12 laboratory strain multiplied in the aphid hemolymph as well as in the digestive tract, resulting in death of infected aphids. Selected gene deletion mutants of the E. coli K-12 predicted to have reduced virulence during systemic infections showed no difference in either replication or killing rate when compared to the wild type E. coli strain. Of note, however, the XL1-Blue E. coli K-12 strain exhibited a significant lag phase before multiplying and killing aphids. This bacterial strain has recently been shown to be more sensitive to oxidative stress than other E. coli K-12 strains, revealing a potential role for reactive oxygen species-mediated defenses in the otherwise reduced aphid immune system.

  9. Intake port

    DOEpatents

    Mendler, Edward Charles

    2005-02-01

    The volumetric efficiency and power of internal combustion engines is improved with an intake port having an intake nozzle, a venturi, and a surge chamber. The venturi is located almost halfway upstream the intake port between the intake valves and the intake plenum enabling the venturi throat diameter to be exceptionally small for providing an exceptionally high ram velocity and an exceptionally long and in turn high efficiency diffuser flowing into the surge chamber. The intake port includes an exceptionally large surge chamber volume for blow down of the intake air into the working cylinder of the engine.

  10. UV-B impact on aphid performance mediated by plant quality and plant changes induced by aphids.

    PubMed

    Kuhlmann, F; Müller, C

    2010-07-01

    Plants face various abiotic and biotic environmental factors and therefore need to adjust their phenotypic traits on several levels. UV-B radiation is believed to impact herbivorous insects via host plant changes. Plant responses to abiotic challenges (UV-B radiation) and their interaction with two aphid species were explored in a multifactor approach. Broccoli plants [Brassica oleracea L. convar. botrytis (L.), Brassicaceae] were grown in two differently covered greenhouses, transmitting either 80% (high UV-B) or 4% (low UV-B) of ambient UV-B. Three-week-old plants were infested with either specialist cabbage aphids [Brevicoryne brassicae (L.), Sternorrhyncha, Aphididae] or generalist green peach aphids [Myzus persicae (Sulzer), Sternorrhyncha, Aphididae]. Plants grown under high-UV-B intensities were smaller and had higher flavonoid concentrations. Furthermore, these plants had reduced cuticular wax coverage, whereas amino acid concentrations of the phloem sap were little influenced by different UV-B intensities. Cabbage aphids reproduced less on plants grown under high UV-B than on plants grown under low UV-B, whereas reproduction of green peach aphids in both plant light sources was equally poor. These results are likely related to the different specialisation-dependent sensitivities of the two species. The aphids also affected plant chemistry. High numbers of cabbage aphid progeny on low-UV-B plants led to decreased indolyl glucosinolate concentrations. The induced change in these glucosinolates may depend on an infestation threshold. UV-B radiation considerably impacts plant traits and subsequently affects specialist phloem-feeding aphids, whereas aphid growth forces broccoli to generate specific defence responses.

  11. Potential effects of plant protease inhibitors, oryzacystatin I and soybean Bowman-Birk inhibitor, on the aphid parasitoid Aphidius ervi Haliday (Hymenoptera, Braconidae).

    PubMed

    Azzouz, H; Campan, E D M; Cherqui, A; Saguez, J; Couty, A; Jouanin, L; Giordanengo, P; Kaiser, L

    2005-08-01

    Protease inhibitors (PIs) have been shown to cause lethal and sublethal effects on aphids depending on the kind of PI and aphid species. Therefore, these proteins might affect aphid parasitoids directly by inhibiting their digestive proteolysis or indirectly via their development in a less suitable host. In our study, the risk of exposure and the potential effects of soybean Bowman-Birk inhibitor (SbBBI) and oryzacystatin I (OCI) on the aphid endoparasitoid Aphidius ervi were investigated using artificial diet to deliver PIs. Immunoassays showed that both SbBBI and OCI were detected in the honeydew of aphids reared on artificial diet containing these recombinant proteins at 100 microg/mL. However, only SbBBI was detected in parasitoid larvae, while this PI could not be detected in adult parasitoids emerged from PI-intoxicated aphids. Enzymatic inhibition assays showed that digestive proteolytic activity of larvae and adults of A. ervi predominantly relies on serine proteases and especially on chymotrypsin-like activity. Bioassays using SbBBI and OCI on artificial diet were performed. A. ervi that developed on intoxicated aphids had impaired fitness. Thus development and parasitism success of parasitoids exposed to OCI were severely affected. On the contrary, SbBBI only altered significantly female size and sex ratio. Direct exposure to PIs through adult food intake did not affect female's longevity, while SbBBI and OCI (100 microg/mL) induced 69% and 30% inhibition of digestive protease activity, respectively. These studies made it possible to estimate the risk of exposure to plant PIs and the sensitivity of the aphid parasitoid A. ervi to these entomotoxins, by combining immunological, biochemical and biological approaches. First it pointed out that only immature stages are affected by PIs. Secondly, it documented two different modes of effect, according to the nature of the PIs and both host and parasitoid susceptibility. OCI prevented the development of A. ervi

  12. Smells like aphids: orchid flowers mimic aphid alarm pheromones to attract hoverflies for pollination

    PubMed Central

    Stökl, Johannes; Brodmann, Jennifer; Dafni, Amots; Ayasse, Manfred; Hansson, Bill S.

    2011-01-01

    Most insects are dependent on chemical communication for activities such as mate finding or host location. Several plants, and especially orchids, mimic insect semiochemicals to attract insects for unrewarded pollination. Here, we present a new case of pheromone mimicry found in the terrestrial orchid Epipactis veratrifolia. Flowers are visited and pollinated by several species of aphidophagous hoverflies, the females of which also often lay eggs in the flowers. The oviposition behaviour of these hoverflies is mainly guided by aphid-derived kairomones. We show that the flowers produce α- and β-pinene, β-myrcene and β-phellandrene, and that these compounds attract and induce oviposition behaviour in female hoverflies. This floral odour profile is remarkably similar to the alarm pheromone released by several aphid species, such as Megoura viciae. We therefore suggest that E. veratrifolia mimics aphid alarm pheromones to attract hoverflies for pollination; this is the first time, to our knowledge, that such a case of mimicry has been demonstrated. PMID:20943694

  13. Smells like aphids: orchid flowers mimic aphid alarm pheromones to attract hoverflies for pollination.

    PubMed

    Stökl, Johannes; Brodmann, Jennifer; Dafni, Amots; Ayasse, Manfred; Hansson, Bill S

    2011-04-22

    Most insects are dependent on chemical communication for activities such as mate finding or host location. Several plants, and especially orchids, mimic insect semiochemicals to attract insects for unrewarded pollination. Here, we present a new case of pheromone mimicry found in the terrestrial orchid Epipactis veratrifolia. Flowers are visited and pollinated by several species of aphidophagous hoverflies, the females of which also often lay eggs in the flowers. The oviposition behaviour of these hoverflies is mainly guided by aphid-derived kairomones. We show that the flowers produce α- and β-pinene, β-myrcene and β-phellandrene, and that these compounds attract and induce oviposition behaviour in female hoverflies. This floral odour profile is remarkably similar to the alarm pheromone released by several aphid species, such as Megoura viciae. We therefore suggest that E. veratrifolia mimics aphid alarm pheromones to attract hoverflies for pollination; this is the first time, to our knowledge, that such a case of mimicry has been demonstrated.

  14. Aphids alter host-plant nitrogen isotope fractionation

    PubMed Central

    Wilson, Alex C. C.; Sternberg, Leonel da S. L.; Hurley, Katherine B.

    2011-01-01

    Plant sap-feeding insects and blood-feeding parasites are frequently depleted in 15N relative to their diet. Unfortunately, most fluid-feeder/host nitrogen stable-isotope studies simply report stable-isotope signatures, but few attempt to elucidate the mechanism of isotopic trophic depletion. Here we address this deficit by investigating the nitrogen stable-isotope dynamics of a fluid-feeding herbivore-host plant system: the green peach aphid, Myzus persicae, feeding on multiple brassicaceous host plants. M. persicae was consistently more than 6‰ depleted in 15N relative to their hosts, although aphid colonized plants were 1.5‰ to 2.0‰ enriched in 15N relative to uncolonized control plants. Isotopic depletion of aphids relative to hosts was strongly related to host nitrogen content. We tested whether the concomitant aphid 15N depletion and host 15N enrichment was coupled by isotopic mass balance and determined that aphid 15N depletion and host 15N enrichment are uncoupled processes. We hypothesized that colonized plants would have higher nitrate reductase activity than uncolonized plants because previous studies had demonstrated that high nitrate reductase activity under substrate-limiting conditions can result in increased plant δ15N values. Consistent with our hypothesis, nitrate reductase activity in colonized plants was twice that of uncolonized plants. This study offers two important insights that are likely applicable to understanding nitrogen dynamics in fluid-feeder/host systems. First, isotopic separation of aphid and host depends on nitrogen availability. Second, aphid colonization alters host nitrogen metabolism and subsequently host nitrogen stable-isotope signature. Notably, this work establishes a metabolic framework for future hypothesis-driven studies focused on aphid manipulation of host nitrogen metabolism. PMID:21646532

  15. Rag Virulence Among Soybean Aphids (Hemiptera: Aphididae) in Wisconsin.

    PubMed

    Crossley, Michael S; Hogg, David B

    2015-02-01

    Soybean aphid, Aphis glycines Matsumura, a pest of soybean, Glycine max (L.) Merr., and native of Asia, invaded North America sometime before 2000 and rapidly became the most significant insect pest of soybean in the upper Midwest. Plant resistance, a key component of integrated pest management, has received significant attention in the past decade, and several resistance (Rag) genes have been identified. However, the efficacy of Rag (Resistance to Aphis glycines) genes in suppressing aphid abundance has been challenged by the occurrence of soybean aphids capable of overcoming Rag gene-mediated resistance. Although the occurrence of these Rag virulent biotypes poses a serious threat to effective and sustainable management of soybean aphid, little is known about the current abundance of biotypes in North America. The objective of this research was to determine the distribution of Rag virulent soybean aphids in Wisconsin. Soybean aphids were collected from Wisconsin during the summers of 2012 and 2013, and assayed for Rag1, Rag2, and Rag1+2 virulence using no-choice tests in a greenhouse. One clone from Monroe County in 2012 reacted like biotype 4, three clones in different counties in 2013 responded like biotype 2, and eight others expressed varying degrees of Rag virulence. Rag virulence in 2013 was observed in aphids from 33% of the sampled sites and was accounted for by just 4.5% of sampled clones, although this is likely a conservative estimate. No-choice test results are discussed in light of current questions on the biology, ecology, and population genetics of soybean aphid. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. APHID: Anomaly Processor in Hardware for Intrusion Detection

    DTIC Science & Technology

    2007-03-01

    turn them into zombies ). The average home user would never know of this intrusion and can be an unwitting pawn in the schemes of attackers. Recent...Chapter III presents the theoretical APHID architecture and testing models. Where possible , implementation specific details are omitted to keep the...model as flexible as possible . Chapter IV presents our implementation of APHID and discusses the process taken to arrive at that implementation. Chapter

  17. Aphid performance changes with plant defense mediated by Cucumber mosaic virus titer.

    PubMed

    Shi, Xiaobin; Gao, Yang; Yan, Shuo; Tang, Xin; Zhou, Xuguo; Zhang, Deyong; Liu, Yong

    2016-04-22

    Cucumber mosaic virus (CMV) causes appreciable losses in vegetables, ornamentals and agricultural crops. The green peach aphid, Myzus persicae Sulzer (Aphididae) is one of the most efficient vectors for CMV. The transmission ecology of aphid-vectored CMV has been well investigated. However, the detailed description of the dynamic change in the plant-CMV-aphid interaction associated with plant defense and virus epidemics is not well known. In this report, we investigated the relationship of virus titer with plant defense of salicylic acid (SA) and jasmonic acid (JA) during the different infection time and their interaction with aphids in CMV-infected tobacco plants. Our results showed that aphid performance changed with virus titer and plant defense on CMV-inoculated plants. At first, plant defense was low and aphid number increased gradually. The plant defense of SA signaling pathway was induced when virus titer was at a high level, and aphid performance was correspondingly reduced. Additionally, the winged aphids were increased. Our results showed that aphid performance was reduced due to the induced plant defense mediated by Cucumber mosaic virus titer. Additionally, some wingless aphids became to winged aphids. In this way CMV could be transmitted with the migration of winged aphids. We should take measures to prevent aphids in the early stage of their occurrence in the field to prevent virus outbreak.

  18. Does aphid salivation affect phloem sieve element occlusion in vivo?

    PubMed Central

    Medina-Ortega, Karla J.

    2013-01-01

    To protect against loss of photo-assimilate-rich phloem sap, plants have evolved several mechanisms to plug phloem sieve tubes in response to damage. In many Fabaceae, each sieve element contains a discrete proteinaceous body called a forisome, which, in response to damage, rapidly transforms from a condensed configuration that does not impede the flow of sap to a dispersed configuration that plugs the sieve element. Aphids and other specialized phloem sap feeders can ingest phloem sap from a single sieve element for hours or days, and to do this, they must be able to suppress or reverse phloem plugging. A recent study provided in vitro evidence that aphid saliva can reverse forisome plugs. The present study tested this hypothesis in vivo by inducing forisome plugs which triggered aphids to switch behaviour from phloem sap ingestion to salivation into the sieve element. After salivating into the sieve element for various periods of time, the aphids were instantaneously cryofixed (freeze fixed) in situ on their leaf. The state of the forisome was then determined in the penetrated sieve element and in nearby non-penetrated sieve elements which served as controls for sieve elements not subjected to direct aphid salivation. Forisomes were almost always in close contact with the stylet tips and thus came into direct contact with the saliva. Nonetheless, forisome plugs in the penetrated sieve element did not revert back to a non-plugging state any faster than those in neighbouring sieve elements that were not subjected to direct aphid salivation. PMID:24127515

  19. Aphid polyphenisms: trans-generational developmental regulation through viviparity

    PubMed Central

    Ogawa, Kota; Miura, Toru

    2013-01-01

    Polyphenism, in which multiple discrete phenotypes develop from a single genotype, is considered to have contributed to the evolutionary success of aphids. Of the various polyphenisms observed in the complex life cycle of aphids, the reproductive and wing polyphenisms seen in most aphid species are conspicuous. In reproductive polyphenism, the reproductive modes can change between viviparous parthenogenesis and sexual reproduction in response to the photoperiod. Under short-day conditions in autumn, sexual morphs (males and oviparous females) are produced parthenogenetically. Winged polyphenism is observed in viviparous generations during summer, when winged or wingless (flightless) aphids are produced depending on a variety of environmental conditions (e.g., density, predators). Here, we review the physiological mechanisms underlying reproductive and wing polyphenism in aphids. In reproductive polyphenism, morph determination (male, oviparous or viviparous female) within mother aphids is regulated by juvenile hormone (JH) titers in the mothers. In wing polyphenism, although JH is considered to play an important role in phenotype determination (winged or wingless), the role is still controversial. In both cases, the acquisition of viviparity in Aphididae is considered to be the basis for maternal regulation of these polyphenisms, and through which environmental cues can be transferred to developing embryos through the physiological state of the mother. Although the mechanisms by which mothers alter the developmental programs of their progeny have not yet been clarified, continued developments in molecular biology will likely unravel these questions. PMID:24478714

  20. Does aphid salivation affect phloem sieve element occlusion in vivo?

    PubMed

    Medina-Ortega, Karla J; Walker, G P

    2013-12-01

    To protect against loss of photo-assimilate-rich phloem sap, plants have evolved several mechanisms to plug phloem sieve tubes in response to damage. In many Fabaceae, each sieve element contains a discrete proteinaceous body called a forisome, which, in response to damage, rapidly transforms from a condensed configuration that does not impede the flow of sap to a dispersed configuration that plugs the sieve element. Aphids and other specialized phloem sap feeders can ingest phloem sap from a single sieve element for hours or days, and to do this, they must be able to suppress or reverse phloem plugging. A recent study provided in vitro evidence that aphid saliva can reverse forisome plugs. The present study tested this hypothesis in vivo by inducing forisome plugs which triggered aphids to switch behaviour from phloem sap ingestion to salivation into the sieve element. After salivating into the sieve element for various periods of time, the aphids were instantaneously cryofixed (freeze fixed) in situ on their leaf. The state of the forisome was then determined in the penetrated sieve element and in nearby non-penetrated sieve elements which served as controls for sieve elements not subjected to direct aphid salivation. Forisomes were almost always in close contact with the stylet tips and thus came into direct contact with the saliva. Nonetheless, forisome plugs in the penetrated sieve element did not revert back to a non-plugging state any faster than those in neighbouring sieve elements that were not subjected to direct aphid salivation.

  1. Immunity and other defenses in pea aphids, Acyrthosiphon pisum

    PubMed Central

    2010-01-01

    Background Recent genomic analyses of arthropod defense mechanisms suggest conservation of key elements underlying responses to pathogens, parasites and stresses. At the center of pathogen-induced immune responses are signaling pathways triggered by the recognition of fungal, bacterial and viral signatures. These pathways result in the production of response molecules, such as antimicrobial peptides and lysozymes, which degrade or destroy invaders. Using the recently sequenced genome of the pea aphid (Acyrthosiphon pisum), we conducted the first extensive annotation of the immune and stress gene repertoire of a hemipterous insect, which is phylogenetically distantly related to previously characterized insects models. Results Strikingly, pea aphids appear to be missing genes present in insect genomes characterized to date and thought critical for recognition, signaling and killing of microbes. In line with results of gene annotation, experimental analyses designed to characterize immune response through the isolation of RNA transcripts and proteins from immune-challenged pea aphids uncovered few immune-related products. Gene expression studies, however, indicated some expression of immune and stress-related genes. Conclusions The absence of genes suspected to be essential for the insect immune response suggests that the traditional view of insect immunity may not be as broadly applicable as once thought. The limitations of the aphid immune system may be representative of a broad range of insects, or may be aphid specific. We suggest that several aspects of the aphid life style, such as their association with microbial symbionts, could facilitate survival without strong immune protection. PMID:20178569

  2. Aggressive mimicry coexists with mutualism in an aphid

    PubMed Central

    Salazar, Adrián; Fürstenau, Benjamin; Quero, Carmen; Pérez-Hidalgo, Nicolás; Carazo, Pau; Font, Enrique; Martínez-Torres, David

    2015-01-01

    Understanding the evolutionary transition from interspecific exploitation to cooperation is a major challenge in evolutionary biology. Ant–aphid relationships represent an ideal system to this end because they encompass a coevolutionary continuum of interactions ranging from mutualism to antagonism. In this study, we report an unprecedented interaction along this continuum: aggressive mimicry in aphids. We show that two morphs clonally produced by the aphid Paracletus cimiciformis during its root-dwelling phase establish relationships with ants at opposite sides of the mutualism–antagonism continuum. Although one of these morphs exhibits the conventional trophobiotic (mutualistic) relationship with ants of the genus Tetramorium, aphids of the alternative morph are transported by the ants to their brood chamber and cared for as if they were true ant larvae. Gas chromatography-mass spectrometry analyses reveal that the innate cuticular hydrocarbon profile of the mimic morph resembles the profile of ant larvae more than that of the alternative, genetically identical nonmimic morph. Furthermore, we show that, once in the brood chamber, mimic aphids suck on ant larva hemolymph. These results not only add aphids to the limited list of arthropods known to biosynthesize the cuticular chemicals of their deceived hosts to exploit their resources but describe a remarkable case of plastic aggressive mimicry. The present work adds a previously unidentified dimension to the classical textbook paradigm of aphid–ant relationships by showcasing a complex system at the evolutionary interface between cooperation and exploitation. PMID:25583474

  3. Facultative bacterial symbionts in aphids confer resistance to parasitic wasps

    PubMed Central

    Oliver, Kerry M.; Russell, Jacob A.; Moran, Nancy A.; Hunter, Martha S.

    2003-01-01

    Symbiotic relationships between animals and microorganisms are common in nature, yet the factors controlling the abundance and distributions of symbionts are mostly unknown. Aphids have an obligate association with the bacterium Buchnera aphidicola (the primary symbiont) that has been shown to contribute directly to aphid fitness. In addition, aphids sometimes harbor other vertically transmitted bacteria (secondary symbionts), for which few benefits of infection have been previously documented. We carried out experiments to determine the consequences of these facultative symbioses in Acyrthosiphon pisum (the pea aphid) for vulnerability of the aphid host to a hymenopteran parasitoid, Aphidius ervi, a major natural enemy in field populations. Our results show that, in a controlled genetic background, infection confers resistance to parasitoid attack by causing high mortality of developing parasitoid larvae. Compared with uninfected controls, experimentally infected aphids were as likely to be attacked by ovipositing parasitoids but less likely to support parasitoid development. This strong interaction between a symbiotic bacterium and a host natural enemy provides a mechanism for the persistence and spread of symbiotic bacteria. PMID:12563031

  4. Constitutive emission of the aphid alarm pheromone, (E)-β-farnesene, from plants does not serve as a direct defense against aphids

    PubMed Central

    2010-01-01

    Background The sesquiterpene, (E)-β-farnesene (EBF), is the principal component of the alarm pheromone of many aphid species. Released when aphids are attacked by enemies, EBF leads aphids to undertake predator avoidance behaviors and to produce more winged offspring that can leave the plant. Many plants also release EBF as a volatile, and so it has been proposed that this compound could act to defend plants against aphid infestation by 1) deterring aphids from settling, 2) reducing aphid performance due to frequent interruption of feeding and 3) inducing the production of more winged offspring. Here we tested the costs and benefits of EBF as a defense against the green peach aphid, Myzus persicae, using transgenic Arabidopsis thaliana lines engineered to continuously emit EBF. Results No metabolic costs of EBF synthesis could be detected in these plants as they showed no differences in growth or seed production from wild-type controls under two fertilizer regimes. Likewise, no evidence was found for the ability of EBF to directly defend the plant against aphids. EBF emission did not significantly repel winged or wingless morphs from settling on plants. Nor did EBF reduce aphid performance, measured as reproduction, or lead to an increase in the proportion of winged offspring. Conclusions The lack of any defensive effect of EBF in this study might be due to the fact that natural enemy attack on individual aphids leads to a pulsed emission, but the transgenic lines tested continuously produce EBF to which aphids may become habituated. Thus our results provide no support for the hypothesis that plant emission of the aphid alarm pheromone EBF is a direct defense against aphids. However, there is scattered evidence elsewhere in the literature suggesting that EBF emission might serve as an indirect defense by attracting aphid predators. PMID:21092302

  5. Constitutive emission of the aphid alarm pheromone, (E)-β-farnesene, from plants does not serve as a direct defense against aphids.

    PubMed

    Kunert, Grit; Reinhold, Carolina; Gershenzon, Jonathan

    2010-11-23

    The sesquiterpene, (E)-β-farnesene (EBF), is the principal component of the alarm pheromone of many aphid species. Released when aphids are attacked by enemies, EBF leads aphids to undertake predator avoidance behaviors and to produce more winged offspring that can leave the plant. Many plants also release EBF as a volatile, and so it has been proposed that this compound could act to defend plants against aphid infestation by 1) deterring aphids from settling, 2) reducing aphid performance due to frequent interruption of feeding and 3) inducing the production of more winged offspring. Here we tested the costs and benefits of EBF as a defense against the green peach aphid, Myzus persicae, using transgenic Arabidopsis thaliana lines engineered to continuously emit EBF. No metabolic costs of EBF synthesis could be detected in these plants as they showed no differences in growth or seed production from wild-type controls under two fertilizer regimes. Likewise, no evidence was found for the ability of EBF to directly defend the plant against aphids. EBF emission did not significantly repel winged or wingless morphs from settling on plants. Nor did EBF reduce aphid performance, measured as reproduction, or lead to an increase in the proportion of winged offspring. The lack of any defensive effect of EBF in this study might be due to the fact that natural enemy attack on individual aphids leads to a pulsed emission, but the transgenic lines tested continuously produce EBF to which aphids may become habituated. Thus our results provide no support for the hypothesis that plant emission of the aphid alarm pheromone EBF is a direct defense against aphids. However, there is scattered evidence elsewhere in the literature suggesting that EBF emission might serve as an indirect defense by attracting aphid predators.

  6. Aphid (Hemiptera: Aphididae) species composition and potential aphid vectors of plum pox virus in Pennsylvania peach orchards.

    PubMed

    Wallis, C M; Fleischer, S J; Luster, D; Gildow, F E

    2005-10-01

    Plum pox, an invasive disease recently identified in Pennsylvania stone fruit orchards, is caused by the aphid-transmitted Plum pox virus (genus Potyvirus, family Potyviridae, PPV). To identify potential vectors, we described the aphid species communities and the seasonal dynamics of the dominant aphid species within Pennsylvania peach orchards. Aphids were trapped weekly in 2002 and 2003 from mid-April through mid-November within two central Pennsylvania orchards by using yellow and green water pan traps. In total, 42 aphid species were identified from both orchards over 2 yr. Within orchards, actual species richness ranged from 24 to 30 species. The Abundance Based Coverage Estimator predicted species richness to range from 30 to 36 species, indicating that trap catches were identifying most aphid species expected to occur in the orchard. Three species, Rhopalosiphum maidis (Fitch), Aphis spiraecola Patch, and Myzus persicae (Sulzer), were consistently dominant across locations and years. Orchard-trapped populations of these three species peaked in a similar chronological sequence each year. As expected, trap color influenced the total number and distribution of the predominate species collected. However, the same dominant species occurred in both yellow and green traps. Based on the seasonal population dynamics reported here and on published vector efficacy studies, the most probable significant PPV vector was identified as A. spiraecola. If the PPV pathogen escapes current quarantine or if subsequent reintroductions of PPV occur, these data will be useful for developing plum pox management strategies.

  7. Toxin delivery by the coat protein of an aphid-vectored plant virus provides plant resistance to aphids.

    PubMed

    Bonning, Bryony C; Pal, Narinder; Liu, Sijun; Wang, Zhaohui; Sivakumar, S; Dixon, Philip M; King, Glenn F; Miller, W Allen

    2014-01-01

    The sap-sucking insects (order Hemiptera), including aphids, planthoppers, whiteflies and stink bugs, present one of the greatest challenges for pest management in global agriculture. Insect neurotoxins offer an alternative to chemical insecticides for controlling these pests, but require delivery into the insect hemocoel. Here we use the coat protein of a luteovirus, an aphid-vectored plant virus, to deliver a spider-derived, insect-specific toxin that acts within the hemocoel. The luteovirid coat protein is sufficient for delivery of fused proteins into the hemocoel of pea aphids, Acyrthosiphon pisum, without virion assembly. We show that when four aphid pest species-A. pisum, Rhopalosiphum padi, Aphis glycines and Myzus persicae-feed on a recombinant coat protein-toxin fusion, either in an experimental membrane sachet or in transgenic Arabidopsis plants, they experience significant mortality. Aphids fed on these fusion proteins showed signs of neurotoxin-induced paralysis. Luteovirid coat protein-insect neurotoxin fusions represent a promising strategy for transgenic control of aphids and potentially other hemipteran pests.

  8. Parasitism of the soybean aphid, Aphis glycines by Binodoxys communis: the role of aphid defensive behaviour and parasitoid reproductive performance

    PubMed Central

    Wyckhuys, K.A.G.; Stone, L.; Desneux, N.; Hoelmer, K.A.; Hopper, K.R.; Heimpel, G.E.

    2009-01-01

    The Asian parasitoid, Binodoxys communis (Gahan) (Hymenoptera: Braconidae), is a candidate for release against the exotic soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), in North America. In this study, we examined preferences by B. communis for the different developmental stages of A. glycines and investigated consequences of these preferences for parasitoid fitness. We also determined to what extent aphid defensive behaviours mediate such preferences. We found that B. communis readily attacks and successfully develops in the different A. glycines developmental stages. Binodoxys communis development time gradually increased with aphid developmental stage, and wasps took longest to develop in alates. An average (±SE) of 54.01±0.08% of parasitized A. glycines alatoid nymphs transformed into winged adult aphids prior to mummification. No-choice assays showed a higher proportion of successful attacks for immature apterous A. glycines nymphs compared to adults and alatoid nymphs. Also, choice trials indicated avoidance and lower attack and oviposition of adults and alatoid nymphs. The different aphid stages exhibited a range of defensive behaviours, including body raising, kicking and body rotation. These defenses were employed most effectively by larger aphids. We discuss implications for the potential establishment, spread and biological control efficacy of A. glycines by B. communis in the event that it is released in North America. PMID:18294416

  9. Can plant bioregulators be potential tools for managing black pecan aphids?

    USDA-ARS?s Scientific Manuscript database

    Some classes of plant bioregulators (PBRs) possess the potential for usage on pecan (Carya illinoinensis [Wangenh.] K. Koch) to protect foliar canopies from black pecan aphid, Melanocallis caryaefoliae (Davis) (Hemiptera: Aphididae), feeding injury. The black pecan aphid elicits localized chlorotic...

  10. Preparing soft-bodied arthropods for microscope examination: Aphids (Insecta: Hemiptera: Aphididae)

    USDA-ARS?s Scientific Manuscript database

    Proper identification of aphids (Hemiptera: Aphididae) require preparation of the specimen on a microscope slide. This training video provides visual instruction on how to prepare aphid specimens on microscope slides for examination and indentification. Steps ranging from collection, specimen clear...

  11. Agronomy of strip intercropping broccoli with alyssum for biological control of aphids

    USDA-ARS?s Scientific Manuscript database

    Organic broccoli growers in California typically control aphids by intercropping broccoli with strips of alyssum (Lobularia maritima (L.) Desv.) which attracts hoverflies (Diptera: Syrphidae) that are important predators of aphids. A three year study with transplanted organic broccoli in Salinas, ...

  12. Autumn leaf colouration: a new hypothesis involving plant-ant mutualism via aphids

    NASA Astrophysics Data System (ADS)

    Yamazaki, Kazuo

    2008-07-01

    Several recent hypotheses on the adaptive significance of autumn leaf colours have focused on specialist aphids. However, these hypotheses have overlooked several factors: the preferential investment by healthy vigorous trees in growth rather than defence against herbivores, variation among aphid species in their responses to bright autumn leaves and plant defences and the occurrence of tritrophic interactions in tree crowns. I incorporate these factors into a hypothesis that autumn leaf colours signal tree quality to myrmecophilous specialist aphids, with the aphids, in turn, attracting aphid-tending ants during the following spring, and the ants defending the trees from other aphids and herbivores. Therefore, bright autumn leaves may have adaptive significance, attracting myrmecophilous specialist aphids and their attending ants and, thus, reducing herbivory and competition among aphids.

  13. New data on aphid fauna (Hemiptera, Aphididae) in Algeria.

    PubMed

    Laamari, Malik; d'Acier, Armelle Coeur; Jousselin, Emmanuelle

    2013-01-01

    A survey of aphids was carried out during the period 2008-2011 in different regions of Algeria by collecting and identifying aphids and their host plants. Aphids were collected from 46 host plants. Forty-six species were reported including thirty-six species which were recorded for the first time in this country and thirty species which were recorded for the first time in the Maghreb (North Africa). This study extends the number of known Algerian aphid to 156 species.

  14. Cereal Aphid Colony Turnover and Persistence in Winter Wheat

    PubMed Central

    Winder, Linton; Alexander, Colin J.; Woolley, Chris; Perry, Joe N.; Holland, John M.

    2014-01-01

    An understanding of spatial and temporal processes in agricultural ecosystems provides a basis for rational decision-making with regards to the management and husbandry of crops, supporting the implementation of integrated farming strategies. In this study we investigated the spatial and temporal distribution of aphid pests (Sitobion avenae and Metopolophium dirhodum) within winter wheat fields. Using an intensive sampling programme we investigated distributions at both the small (single shoot) and large (field) scales. Within two fields, a grid with 82 locations was established (area 120 m by 168 m). At each location, 25 shoots were individually marked and aphid counts by observation conducted on 21 and 22 occasions as the crop matured, resulting in 43,050 and 45,100 counts being conducted in the two fields respectively. We quantified field scale spatial distributions, demonstrating that spatial pattern generally emerged, with temporal stability being both species- and field- dependent. We then measured turnover of colonies at the small (individual shoot) and large (field) scales by comparing consecutive pairs of sampling occasions. Four turnover categories were defined: Empty (no aphids recorded on either occasion); Colonised (aphids recorded on the second occasion but not the first); Extinction (aphids recorded on the first occasion but not the second); Stable (aphids recorded on both occasions). At the field scale, population stability soon established, but, at the small scale there was a consistently high proportion of unoccupied shoots with considerable colonisation and extinction and low stability. The redistribution of aphids within the crop at the local scale is a vulnerability which could be used to disrupt population development – by mediating exposure to ground-active natural enemies and by incurring a metabolic cost caused by the physiological demands to re-establish on a nearby host plant. PMID:25268240

  15. Aphid Transmission of the Ontario Isolate of Plum Pox Virus.

    PubMed

    Lowery, D Thomas; Vickers, Patricia M; Bittner, Lori A; Stobbs, Lorne W; Foottit, Robert G

    2015-10-01

    Utilization of timed virus acquisition access probes in studies of plum pox virus (PPV) transmission by aphids demonstrated that endemic species transmitted the virus readily from plum, Prunus domestica (L.) Batsch; peach, P. persica (L.); or dwarf flowering almond, P. glandulosa Thunberg., to peach seedlings. The green peach aphid, Myzus persicae (Sulzer), was shown to be the most efficient vector. Acquisition of virus by green peach aphids from infected peach leaves resulted in 18-28% infected peach seedlings, while aphids previously fed on infected leaves of plum transferred virus to 36% of peach seedlings. Although the spirea aphid, Aphis spiraecola (Patch), was a less efficient vector than M. persicae it is perhaps more important for the spread of PPV due to its greater abundance and occurrence earlier in the season when peach trees are thought to be more susceptible to infection. Virus transmission rates varied depending on the virus source and healthy test plant species. In contrast to many previous studies, aphid inoculation of the experimental host Nicotiana benthamiana Domin occurred at a low rate, never exceeding 4%. Acquisition of PPV by M. persicae from infected peach fruit was greatly reduced compared with acquisition from leaves. The results of this research indicate that the Ontario isolate of PPV-D is readily transmissible by aphids to peach and natural spread of the virus needs to be considered in future management or eradication programs. © Her Majesty in Right of Canada, as represented by the Minister of Agriculture and Agri-Food Canada. Published by Oxford University Press on behalf of Entomological Society of America.

  16. Ethylene production and peroxidase activity in aphid-infested barley.

    PubMed

    Argandoña, V H; Chaman, M; Cardemil, L; Muñoz, O; Zúñiga, G E; Corcuera, L J

    2001-01-01

    The purpose of this work was to investigate whether ethylene is involved in the oxidative and defensive responses of barley to the aphids Schizaphis graminum (biotype C) and Rhopalophum padi. The effect of aphid infestation on ethylene production was measured in two barley cultivars (Frontera and Aramir) that differ in their susceptibility to aphids. Ethylene evolution was higher in plants infested for 16 hr than in plants infested for 4 hr in both cultivars. Under aphid infestation, the production of ethylene was higher in cv. Frontera than in Aramir, the more aphid susceptible cultivar. Ethylene production also increases with the degree of infestation. Maximum ethylene evolution was detected after 16 hr when plants were infested with 10 or more aphids. Comparing the two species of aphids, Schizaphis graminum induced more ethylene evolution than Rhopalosiphum padi. Infestation with S. graminum increased hydrogen peroxide content and total soluble peroxidase activity in cv. Frontera, with a maximum level of H2O2 observed after 20 min of infestation and the maximum in soluble peroxidase activity after 30 min of infestation. When noninfested barley seedlings from cv. Frontera were exposed to ethylene, an increase in hydrogen peroxide and in total peroxidase activity was detected at levels similar to those of infested plants from cv. Frontera. When noninfested plants were treated with 40 ppm of ethylene, the maximum levels of H2O2 and soluble peroxidase activity were at 10 and 40 min, respectively. Ethylene also increased the activity of both cell-wall-bound peroxidases types (ionically and covalently bound), comparable with infestation. These results suggest that ethylene is involved in the oxidative responses of barley plants induced by infestation.

  17. Suppression of plant defenses by a Myzus persicae (green peach aphid) salivary effector protein.

    PubMed

    Elzinga, Dezi A; De Vos, Martin; Jander, Georg

    2014-07-01

    The complex interactions between aphids and their host plant are species-specific and involve multiple layers of recognition and defense. Aphid salivary proteins, which are released into the plant during phloem feeding, are a likely mediator of these interactions. In an approach to identify aphid effectors that facilitate feeding from host plants, eleven Myzus persicae (green peach aphid) salivary proteins and the GroEL protein of Buchnera aphidicola, a bacterial endosymbiont of this aphid species, were expressed transiently in Nicotiana tabacum (tobacco). Whereas two salivary proteins increased aphid reproduction, expression of three other aphid proteins and GroEL significantly decreased aphid reproduction on N. tabacum. These effects were recapitulated in stable transgenic Arabidopsis thaliana plants. Further experiments with A. thaliana expressing Mp55, a salivary protein that increased aphid reproduction, showed lower accumulation of 4-methoxyindol-3-ylmethylglucosinolate, callose and hydrogen peroxide in response to aphid feeding. Mp55-expressing plants also were more attractive for aphids in choice assays. Silencing Mp55 gene expression in M. persicae using RNA interference approaches reduced aphid reproduction on N. tabacum, A. thaliana, and N. benthamiana. Together, these results demonstrate a role for Mp55, a protein with as-yet-unknown molecular function, in the interaction of M. persicae with its host plants.

  18. Distribution of the black pecan aphid on pecan leaf surfaces: an overview

    USDA-ARS?s Scientific Manuscript database

    Three species of aphids (Hemiptera: Aphididae) regularly attack pecan, Carya illinoinensis, foliage. Two of these species, i.e., the blackmargined aphid, Monellia caryella and the yellow pecan aphid, Monelliopsis pecanis, are predominantly distributed on the abaxial leaf surface, as are adults and ...

  19. Release of Predators of the Balsam Woolly Aphid in North Carolina

    Treesearch

    Gene D. Amman; Charles F. Speers

    1964-01-01

    The balsam woolly aphid, Chermes piceae Ratz. (Homoptera: Chermidae), was accidentally introduced into North America from Europe about 1900 (Balch 1952). The aphid is now a serious pest of Fraser fir, Abies fraseri (Pursh)Poir., in the Southern Appalachians. Since its discovery in Northo-1957 (Speers 1958), the aphid has killed thousands of trees annually. Fraser fir...

  20. Tetramorium tsushimae Ants Use Methyl Branched Hydrocarbons of Aphids for Partner Recognition.

    PubMed

    Sakata, Itaru; Hayashi, Masayuki; Nakamuta, Kiyoshi

    2017-10-04

    In mutualisms, partner discrimination is often the most important challenge for interacting organisms. The interaction between ants and aphids is a model system for studying mutualisms; ants are provided with honeydew by aphids and, in turn, the ants offer beneficial services to the aphids. To establish and maintain this system, ants must discriminate mutualistic aphid species correctly. Although recent studies have shown that ants recognize aphids as mutualistic partners based on their cuticular hydrocarbons (CHCs), it was unclear which CHCs are involved in recognition. Here, we tested whether the n-alkane or methylalkane fraction, or both, of aphid CHCs were utilized as partner recognition cues by measuring ant aggressiveness toward these fractions. When workers of Tetramorium tsushimae ants were presented with dummies coated with n-alkanes of their mutualistic aphid Aphis craccivora, ants displayed higher levels of aggression than to dummies treated with total CHCs or methyl alkanes of A. craccivora; responses to dummies treated with n-alkanes of A. craccivora were similar to those to control dummies or dummies treated with the CHCs of the non-mutualistic aphid Acyrthosiphon pisum. By contrast, ants exhibited lower aggression to dummies treated with either total CHCs or the methylalkane fraction of the mutualistic aphid than to control dummies or dummies treated with CHCs of the non-mutualistic aphid. These results suggest that T. tsushimae ants use methylalkanes of the mutualistic aphid's CHCs to recognize partners, and that these ants do not recognize aphids as partners on the basis of n-alkanes.

  1. Comparison of transmission efficiency of different isolates of Potato virus Y among three aphid vectors

    USDA-ARS?s Scientific Manuscript database

    Potato virus Y (PVY) strains are transmitted by different aphid species in a non-persistent, non-circulative manner. Green peach aphid (GPA, Myzus persicae Sulzer; Aphididae, Macrosiphini) is the most efficient vector in laboratory studies, but potato aphid (PA, Macrosiphum euphorbiae Thomas; Aphidi...

  2. Development of Soybean Aphid Genomic and EST-SSR Markers using Next Generation Sequencing

    USDA-ARS?s Scientific Manuscript database

    The soybean aphid (Aphis glycines Matsumura) has become the most damaging insect pest of soybean in most of North American soybean growing regions. Biotypes of soybean aphid capable of breaking down the resistance of newly developed aphid resistant soybean cultivars were discovered recently. But gen...

  3. National Plant Diagnostic Network, Taxonomic training videos: Introduction to AphID

    USDA-ARS?s Scientific Manuscript database

    Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides visual instruction on the use of the expert system, AphID, for aphid examination and identification. The video demonstrates the use of different training modules that allow the user to gain familiarity wi...

  4. National Plant Diagnostic Network, Taxonomic training videos: Aphids under the microscope - overview

    USDA-ARS?s Scientific Manuscript database

    Training is a critical part of aphid (Hemiptera: Aphididae) identification. This training video provides provides an overview of general aphid morphology by using a compound microscope. The narrator discusses and highlights structures on the aphid that are important to make a species identification....

  5. Spectral sensing of aphid (Hemiptera: Aphididae) density using field spectrometry and radiometry

    USDA-ARS?s Scientific Manuscript database

    The greenbug, Schizaphis graminum (Rondani), and bird cherry-oat aphid, Rhopalosiphum padi L., are aphid pests of wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), sorghum (Sorghum bicolor L.), oat (Avena sativa L.), and other cereals worldwide. Greenbug and bird cherry-oat aphid infestati...

  6. The Nerium oleander aphid Aphis nerii is tolerant to a local isolate of Aphid lethal paralysis virus (ALPV).

    PubMed

    Dombrovsky, Aviv; Luria, Neta

    2013-04-01

    In a survey that was conducted during the year 2011, a local strain of Aphid lethal paralysis virus (ALPV) was identified and isolated from a wild population of Aphis nerii aphids living on Nerium oleander plants located in northern Israel. The new strain was tentatively named (ALPV-An). RNA extracted from the viral particles allowed the amplification and determination of the complete genome sequence. The virus genome is comprised of 9835 nucleotides. In a BLAST search analysis, the ALPV-An sequence showed 89 % nucleotide sequence identity with the whole genome of a South African ALPV and 96 and 94 % amino acid sequence identity with the ORF1 and ORF2 of that strain, respectively. In preliminary experiments, spray-applied, purified ALPV virions were highly pathogenic to the green peach aphid Myzus persicae; 95 % mortality was recorded 4 days post-infection. These preliminary results demonstrate the potential of ALPV for use as a biologic agent for some aphid control. Surprisingly, no visible ALPV pathogenic effects, such as morphological changes or paralysis, were observed in the A. nerii aphids infected with ALPV-An. The absence of clear ALPV symptoms in A. nerii led to the formulation of two hypotheses, which were partially examined in this study. The first hypothesis suggest that A. nerii is resistant or tolerant of ALPV, while the second hypothesis propose that ALPV-An may be a mild strain of ALPV. Currently, our results is in favor with the first hypothesis since ALPV-An is cryptic in A. nerii aphids and can be lethal for M. persicae aphids.

  7. Particle film affects black pecan aphid (Homoptera: Aphididae) on pecan.

    PubMed

    Cottrell, Ted E; Wood, Bruce W; Reilly, Charles C

    2002-08-01

    Three species of aphids attack pecan foliage, Carya illinoensis (Wang.) K. Koch, and cause economic damage. We tested a kaolin-based particle film against one of these aphid species, black pecan aphid, Melanocallis caryaefoliae (Davis). Effect of particle film on host selection, adult mortality, and production of nymphs by M. caryaefoliae was tested on seedling pecans in the laboratory. Fewer M. caryaefoliae adults selected treated foliage compared with untreated foliage. A higher percentage of adults that did select treated foliage were recovered from upper leaf surfaces compared with the percentage of adults recovered from upper leaf surfaces of untreated leaves. Observations with a microscope revealed an accumulation of particle film on aphid body parts, especially on tarsi, and strongly suggests that aphid mobility was restricted. Adult mortality was higher on treated foliage and led to an overall decrease in production of nymphs on those seedlings. In addition, we measured spectral properties of treated seedling pecan foliage. Light reflectance by treated foliage was increased and absorptance decreased compared with control foliage whereas transmittance of light through control and particle film-treated leaves was similar. We did not detect any phytotoxic effect on pecan due to application of particle film.

  8. Kin structure provides no explanation for intruders in social aphids.

    PubMed

    Abbot, Patrick; Chhatre, Vikram

    2007-09-01

    Nontraditional social organisms have received increasing attention in recent years, because they present opportunities to study the convergent properties of social evolution. Some aphid species are social, occurring in dense clones with specialized morphs that attack predators and parasites. Little is known about how social aphid colonies resolve conflicts of interest when clonal barriers break down. Pemphigus obesinymphae is a North American gall-forming social aphid that produces both nymphal defenders that protect natal clones, and specialized intruders that invade other nearby clones on their host plants. We tested the hypothesis that clones are arranged on their host plants in spatial clusters of related family groups, such that intruders would be biased towards movement within kin groups. Movement within and not between kin groups would then provide insight into the nature of conflict in this social aphid. We sampled eight sites in the eastern United States and in Arizona, and used eight microsatellite markers to estimate pairwise relatedness between spatial groups. We found little evidence of deviation from random distributions of genotypes on their host plants. Evidently, Pem. obesinymphae intruders typically exploit unrelated clones, and spatial orientation provides no solution to the problem of 'polyclonality' in this species. We discuss implications of this result for our understanding of cooperation and conflict in social aphids.

  9. Mechanisms regulating caste differentiation in an aphid social system.

    PubMed

    Shibao, Harunobu; Kutsukake, Mayako; Matsuyama, Shigeru; Fukatsu, Takema; Shimada, Masakazu

    2010-01-01

    For evolution and maintenance of the social systems of insect colonies, caste production should be controlled in response to external cues so that caste ratio in the colony is kept at an optimal range. Recent developments using artificial diet rearing techniques have revealed an underlying mechanism for adaptive control of caste production in a social aphid, Tuberaphis styraci, which has a sterile soldier caste in the 2(nd) instar. Aphid density was the proximate cue that acts on 1(st) instar nymphs and embryos to induce soldier differentiation. The final determination of soldier differentiation occurred postnatally, probably at a late 1(st) instar stage. Direct contact stimuli from live non-soldier aphids mediated the density effect. While coexisting non-soldiers facilitated soldier differentiation in 1(st) instar nymphs, coexisting soldiers acted to suppress such differentiation. These results suggest that caste production in aphid colonies is controlled by positive and negative feedback mechanisms consisting of density-dependent induction and suppression of soldier differentiation. Here, we demonstrate the mechanisms that coordinate aphid society, and provide a striking case of clonal superorganism system where simple responses of colony members to local extrinsic stimuli are integrated into a highly organized regulation of the whole colony.

  10. Prevalence of entomophthoralean fungi (Entomophthoromycota) of aphids (Hemiptera: Aphididae) on solanaceous crops in Argentina.

    PubMed

    Manfrino, R G; Gutiérrez, A C; Steinkraus, D C; Salto, C E; López Lastra, C C

    2014-09-01

    Solanum melongena L. and Capsicum annuum L. were sampled in Argentina to determine the prevalence of fungal diseased aphids. The pathogens identified were Pandora neoaphidis (Remaudière & Hennebert) Humber and Zoophthora radicans (Brefeld) Batko (Entomophthorales: Entomophthoraceae) on aphids from eggplants; and P. neoaphidis and Entomophthora planchoniana Cornu (Entomophthorales: Entomophthoraceae) on aphids from peppers. The highest fungal prevalence was 45.5% (n=2296) and 98.1% (n=3212) from aphids on eggplants and peppers, respectively. In both crops, significant differences were found on number of infected aphids among developmental stages. P.neoaphidis and E. planchoniana caused epizootics in M. persicae.

  11. Ramjet Intakes

    DTIC Science & Technology

    2010-09-01

    allow intakes to function over large Mach number ranges and at relatively low Reynolds numbers. The NASA Hypersonic Research Engine, the BAC/SUD...Concorde and the Lockheed SR-71 will serve as an introduction to this aspect of intake design. 4.2 NASA Hypersonic research engine The Hypersonic Research...results of the inlet for the nasa hypersonic research engine aerothermodynamic integration model, NASA-TMX-3365; Ramjet Intakes RTO-EN-AVT-185 5

  12. Susceptibilities of apple aphid and spirea aphid collected from apple in the Pacific Northwest to selected insecticides.

    PubMed

    Lowery, D Thomas; Smirle, Michael J; Foottit, Robert G; Beers, Elizabeth H

    2006-08-01

    Laboratory bioassays using leaf disks of apple dipped in test solutions of insecticides demonstrated that the apple aphid, Aphis pomi De Geer, and the spirea aphid, Aphis spiraecola Patch, differed significantly in susceptibility to a number of insecticides registered for control of aphids on apple (Malus spp.). Compared with A. pomi, A. spiraecola was approximately four- and three-fold less susceptible to pirimicarb and lambda-cyhalothrin, respectively, whereas there was little difference in response to dimethoate. Pymetrozine is thought to act on aphids primarily as a feeding inhibitor. Exposure of aphids to this material generated data that fit the probit model for only half the tested clones. However, the LC50 value for one clone of A. spiraecola was nearly 1,000 times higher than the value for one clone of A. pomi. Although the results from these trials did not indicate that either species had developed significant levels of resistance to the test materials, differences in LC50 levels of > 10-fold suggest insecticide tolerances and the possibility of control failures in the future. The demonstrated differences in susceptibility to insecticides between these two morphologically similar species also should be considered during the evaluation of new products for use on apple.

  13. Virulent Diuraphis noxia Aphids Over-Express Calcium Signaling Proteins to Overcome Defenses of Aphid-Resistant Wheat Plants

    PubMed Central

    Sinha, Deepak K.; Chandran, Predeesh; Timm, Alicia E.; Aguirre-Rojas, Lina; Smith, C. Michael

    2016-01-01

    The Russian wheat aphid, Diuraphis noxia, an invasive phytotoxic pest of wheat, Triticum aestivum, and barley, Hordeum vulgare, causes huge economic losses in Africa, South America, and North America. Most acceptable and ecologically beneficial aphid management strategies include selection and breeding of D. noxia-resistant varieties, and numerous D. noxia resistance genes have been identified in T. aestivum and H. vulgare. North American D. noxia biotype 1 is avirulent to T. aestivum varieties possessing Dn4 or Dn7 genes, while biotype 2 is virulent to Dn4 and avirulent to Dn7. The current investigation utilized next-generation RNAseq technology to reveal that biotype 2 over expresses proteins involved in calcium signaling, which activates phosphoinositide (PI) metabolism. Calcium signaling proteins comprised 36% of all transcripts identified in the two D. noxia biotypes. Depending on plant resistance gene-aphid biotype interaction, additional transcript groups included those involved in tissue growth; defense and stress response; zinc ion and related cofactor binding; and apoptosis. Activation of enzymes involved in PI metabolism by D. noxia biotype 2 aphids allows depletion of plant calcium that normally blocks aphid feeding sites in phloem sieve elements and enables successful, continuous feeding on plants resistant to avirulent biotype 1. Inhibition of the key enzyme phospholipase C significantly reduced biotype 2 salivation into phloem and phloem sap ingestion. PMID:26815857

  14. Effects of chemically contaminated sewage sludge on an aphid population

    SciTech Connect

    Culliney, T.W.; Pimentel, D.

    1986-12-01

    Survival and fecundity of green peach aphids, Myzus persicae, were markedly reduced when they were fed on collard plants grown in pots of soil treated with chemically contaminated sewage sludge, as compared to populations on potted plants grown in uncontaminated sludge or on fertilized soil (control). Calculated demographic parameters differed significantly between the contaminated sludge and uncontaminated sludge populations and between the contaminated sludge and control populations. No significant differences were detected between the uncontaminated sludge and control populations. The ecological effects on the aphids suggest that plant uptake and translocation of chemicals from the contaminated sludge affected aphid fitness through direct toxicity and/or reduced nutritional value of the plant. These results indicate that phytophagous insects may be affected by chemical contaminants in sewage sludge used in agriculture.

  15. Aphidophagous Parasitoids can Forage Wheat Crops Before Aphid Infestation, Parana State, Brazil

    PubMed Central

    Ceolin Bortolotto, Orcial; de Oliveira Menezes Júnior, Ayres; Thibes Hoshino, Adriano

    2015-01-01

    Aphid parasitoids are common in Brazilian wheat fields, and parasitize aphids at the wheat tillering stage. However, there is little information available about when this natural enemy occurs in wheat crops. This study investigated the initial occurrence of aphid parasitoids in four commercial wheat crops in northern Paraná during the 2009 crop season. We installed two Malaise traps at each wheat farm, and 400 tillers were assessed weekly in each field for aphid abundance. During this study, we captured 4,355 aphid parasitoids and 197 aphids. Three species of braconid parasitoids were identified, including Aphidius colemani (Viereck 1912), Lysiphlebus testaceipes (Cresson 1880), and Diaeretiella rapae (McIntosh 1855). The aphids species identified were Rhopalosiphum padi (Linnaeus 1758) and Sitobion avenae (Fabricius 1775). This study showed that aphid parasitoids are present in wheat crops even when aphid densities are low, and in one farm, occurred before the aphids colonization. These reports can justified the high efficiency of these natural enemies against aphids in wheat fields. PMID:25843593

  16. Soybean aphid intrabiotype variability based on colonization of specific soybean genotypes.

    PubMed

    Pawlowski, Michelle; Hill, Curtis B; Voegtlin, David J; Hartman, Glen L

    2015-12-01

    The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is one of the most destructive insect pests on soybeans in the United States. One method for managing this pest is through host plant resistance. Since its arrival in 2000, 4 aphid biotypes have been identified that are able to overcome soybean aphid resistance (Rag) genes. A soybean aphid isolate collected from Moline, Illinois readily colonized soybean plants with the soybean aphid resistance gene Rag2, unlike biotypes 1 and 2, but similar to soybean aphid biotype 3. Two no-choice experiments compared the virulence of the Moline isolate with biotype 3. In both experiments, differences in aphid population counts were not significant (P > 0.05) on soybean genotypes LD08-12957a (Rag2) and LD11-5413a (Rag2), but the aphid counts for the Moline isolate were significantly (P < 0.05) lower than the aphid counts for the biotype 3 isolate on the soybean genotypes Dowling (Rag1), LD05-16611 (Rag1), LD11-4576a (Rag1), and PI 567598B (rag1b and rag3). The Moline isolate was a variant of aphid biotype 3, which is the first report showing that soybean aphid isolates classified as the same biotype, based on virulence against specific Rag genes, can differ in aggressiveness or ability to colonize specific host genotypes.

  17. Stem nematode counteracts plant resistance of aphids in alfalfa, Medicago sativa.

    PubMed

    Ramirez, Ricardo A; Spears, Lori R

    2014-10-01

    Plants are exploited by a diverse community of insect herbivores and phytopathogens that interact indirectly through plant-mediated interactions. Generally, plants are thought to respond to insects and pathogens through different defensive signaling pathways. As plants are selected for resistance to one phytophagous organism type (insect vs. pathogen) in managed systems, it is not clear how this selection may affect community interactions. This study examined the effect of nematode-resistant varieties on aphid (Acyrthosiphon pisum) suppression, and then determined how infection by the stem nematode, Ditylenchus dipsaci, mediated ecological effects on aphids and on plant defense proteins. Four alfalfa (Medicago sativa) varieties were selected with resistance to nematodes only (+,-), aphids only (-,+), nematodes and aphids (+,+), and susceptibility to nematodes and aphids (-,-). Field and greenhouse experiments were conducted to isolate the effect of nematode infection and aphid abundance on each variety. We found that varieties resistant to nematode, regardless of aphid resistance, had the lowest aphid counts, suggesting possible cross-resistance. Aphid abundance, however, increased when plants were exposed to nematodes. Resistant varieties were associated with elevated saponins but these compounds were not affected by insect or pathogen feeding. Concentrations of peroxidases and trypsin inhibitors, however, were increased in nematode resistant varieties when exposed to nematodes and aphids, respectively. The patterns of plant defense were variable, and a combination of resistance traits and changes in nutrient availability may drive positive interactions between nematodes and aphids aboveground.

  18. Selection of entomopathogenic fungi for aphid control.

    PubMed

    Vu, Van Hanh; Hong, Suk Il; Kim, Keun

    2007-12-01

    Twelve strains of entomopathogenic fungi such as Lecanicillium lecanii, Paecilomyces farinosus, Beauveria bassiana, Metarhizium anisopliae, Cordyceps scarabaeicola, and Nomuraea rileyi were screened for aphid control. At 25 degrees C and 75% relative humidity (RH), among tested entomopathogenic fungi, L. lecanii 41185 showed the highest virulent pathogenicity for both Myzus persicae and Aphis gossypii, and their control values were both nearly 100% 5 and 2 d after treatment, respectively. Moreover, at an RH of 45% and in a wide temperature range (20-30 degrees C), L. lecanii 41185 also exhibited the highest virulence to M. persicae. The control value of M. persicae and the 50% lethal time (LT50) decreased significantly as the applied conidial concentration increased. The 50% lethal concentration (LC50) of the conidial suspension of this fungus was determined to be 6.55x10(5) conidia/ml. The control values of M. persicae resulting from the application of 1x10(7) and 1x10(8) conidia/ml were nearly the same and were significantly higher than that of 1x10(6) conidia/ml. The tested entomopathogenic fungi grew in a broad temperature range (15-30 degrees C). Lecanicillium strains showed optimum growth at 25 degrees C. The aerial conidia of Lecanicillium strains also could germinate in a broad temperature range (15-30 degrees C) and L. lecanii 41185 was the only strain with conidial germination at 35 degrees C.

  19. Pea Aphids (Hemiptera: Aphididae) Have Diurnal Rhythms When Raised Independently of a Host Plant.

    PubMed

    Joschinski, Jens; Beer, Katharina; Helfrich-Förster, Charlotte; Krauss, Jochen

    2016-01-01

    Seasonal timing is assumed to involve the circadian clock, an endogenous mechanism to track time and measure day length. Some debate persists, however, and aphids were among the first organisms for which circadian clock involvement was questioned. Inferences about links to phenology are problematic, as the clock itself is little investigated in aphids. For instance, it is unknown whether aphids possess diurnal rhythms at all. Possibly, the close interaction with host plants prevents independent measurements of rhythmicity. We reared the pea aphid Acyrthosiphon pisum(Harris) on an artificial diet, and recorded survival, moulting, and honeydew excretion. Despite their plant-dependent life style, aphids were independently rhythmic under light-dark conditions. This first demonstration of diurnal aphid rhythms shows that aphids do not simply track the host plant's rhythmicity.

  20. Two species of symbiotic bacteria present in the soybean aphid (Hemiptera: Aphididae).

    PubMed

    Wille, B D; Hartman, G L

    2009-02-01

    Aphids, which feed solely on plant phloem sap, have developed symbiotic associations with bacteria that provide them with the amino acids that are lacking in phloem. Three soybean aphid (Aphis glycines Mat samura) populations were screened for the presence of Buchnera aphidicola and three common species of secondary aphid symbionts (Serratia symbiotica, Hamiltonella defensa, and Regiella insecticola). Diagnostic polymerase chain reaction and subsequent DNA sequencing showed the presence of two species of symbiotic bacteria present in all three soybean aphid populations tested: B. aphidicola and Arsenophonus sp. Although Buchnera is commonly found in aphids, Arsenophonus is most commonly found in whiteflies (Hemiptera: Aleyrodidae), making the soybean aphid unique among aphids that have been tested for the presence of Arsenophonus.

  1. The NIa-Pro protein of Turnip mosaic virus improves growth and reproduction of the aphid vector, Myzus persicae (green peach aphid).

    PubMed

    Casteel, Clare L; Yang, Chunling; Nanduri, Ananya C; De Jong, Hannah N; Whitham, Steven A; Jander, Georg

    2014-02-01

    Many plant viruses depend on aphids and other phloem-feeding insects for transmission within and among host plants. Thus, viruses may promote their own transmission by manipulating plant physiology to attract aphids and increase aphid reproduction. Consistent with this hypothesis, Myzus persicae (green peach aphids) prefer to settle on Nicotiana benthamiana infected with Turnip mosaic virus (TuMV) and fecundity on virus-infected N. benthamiana and Arabidopsis thaliana (Arabidopsis) is higher than on uninfected controls. TuMV infection suppresses callose deposition, an important plant defense, and increases the amount of free amino acids, the major source of nitrogen for aphids. To investigate the underlying molecular mechanisms of this phenomenon, 10 TuMV genes were over-expressed in plants to determine their effects on aphid reproduction. Production of a single TuMV protein, nuclear inclusion a-protease domain (NIa-Pro), increased M. persicae reproduction on both N. benthamiana and Arabidopsis. Similar to the effects that are observed during TuMV infection, NIa-Pro expression alone increased aphid arrestment, suppressed callose deposition and increased the abundance of free amino acids. Together, these results suggest a function for the TuMV NIa-Pro protein in manipulating the physiology of host plants. By attracting aphid vectors and promoting their reproduction, TuMV may influence plant-aphid interactions to promote its own transmission.

  2. Spatial and Temporal Dynamics of Aphids (Hemiptera: Aphididae) in the Columbia Basin and Northeastern Oregon.

    PubMed

    Klein, Mathew L; Rondon, Silvia I; Walenta, Darrin L; Zeb, Qamar; Murphy, Alexzandra F

    2017-08-01

    Aphid species, such as the potato aphid, Macrosiphum euphorbiae Thomas, and the green peach aphid, Myzus persicae Sulzer, are routinely considered the most important pests of potatoes. Potato aphid, green peach aphid, and more recently, other aphids such as the bird cherry-oat aphid Rhopalosiphum padi L. have been identified as vectors of multiple plant pathogenic viruses in potatoes. Since 2006, an area-wide trapping network consisting of ∼60 sites was developed through collaboration between researchers, extension faculty, and stakeholders, to monitor aphid populations in the Columbia Basin of Oregon (Umatilla and Morrow counties) and in northeastern Oregon (Union and Baker counties). Over a 9-yr period (2006 to 2014), aphid specimens were collected weekly using yellow bucket traps and specimens were then identified and counted to determine population levels during the growing season (May-September). Thus, aphid population data were compiled and subjected to spatial and temporal distribution analysis. Weather data, obtained from an established network of weather stations located in the monitoring areas, were used in a nonparametric multiplicative regression analysis to determine which abiotic variables may impact aphid populations. Weather conditions were characterized using confidence intervals (CIs) established based on weather data from 1999 to 2005 for each environmental variable. Aphid populations were found to have a heterogeneous distribution in most years; a few sites had high aphid populations while low numbers were observed at most sites; aphids were also found to correlate with several abiotic variables, namely, elevation, previous season temperature, and previous season dew point. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Persistence and transgenerational effect of plant-mediated RNAi in aphids.

    PubMed

    Coleman, A D; Wouters, R H M; Mugford, S T; Hogenhout, S A

    2015-02-01

    Plant-mediated RNA interference (RNAi) has been successfully used as a tool to study gene function in aphids. The persistence and transgenerational effects of plant-mediated RNAi in the green peach aphid (GPA) Myzus persicae were investigated, with a focus on three genes with different functions in the aphid. Rack1 is a key component of various cellular processes inside aphids, while candidate effector genes MpC002 and MpPIntO2 (Mp2) modulate aphid-plant interactions. The gene sequences and functions did not affect RNAi-mediated down-regulation and persistence levels in the aphids. Maximal reduction of gene expression was ~70% and this was achieved at between 4 d and 8 d of exposure of the aphids to double-stranded RNA (dsRNA)-producing transgenic Arabidopsis thaliana. Moreover, gene expression levels returned to wild-type levels within ~6 d after removal of the aphids from the transgenic plants, indicating that a continuous supply of dsRNA is required to maintain the RNAi effect. Target genes were also down-regulated in nymphs born from mothers exposed to dsRNA-producing transgenic plants, and the RNAi effect lasted twice as long (12-14 d) in these nymphs. Investigations of the impact of RNAi over three generations of aphids revealed that aphids reared on dsMpC002 transgenic plants experienced a 60% decline in aphid reproduction levels compared with a 40% decline of aphids reared on dsRack1 and dsMpPIntO2 plants. In a field setting, a reduction of the aphid reproduction by 40-60% would dramatically decrease aphid population growth, contributing to a substantial reduction in agricultural losses.

  4. Long-term phenological trends, species accumulation rates, aphid traits and climate: five decades of change in migrating aphids

    PubMed Central

    Bell, James R; Alderson, Lynda; Izera, Daniela; Kruger, Tracey; Parker, Sue; Pickup, Jon; Shortall, Chris R; Taylor, Mark S; Verrier, Paul; Harrington, Richard

    2015-01-01

    1. Aphids represent a significant challenge to food production. The Rothamsted Insect Survey (RIS) runs a network of 12·2-m suction-traps throughout the year to collect migrating aphids. In 2014, the RIS celebrated its 50th anniversary. This paper marks that achievement with an extensive spatiotemporal analysis and the provision of the first British annotated checklist of aphids since 1964. 2. Our main aim was to elucidate mechanisms that advance aphid phenology under climate change and explain these using life-history traits. We then highlight emerging pests using accumulation patterns. 3. Linear and nonlinear mixed-effect models estimated the average rate of change per annum and effects of climate on annual counts, first and last flights and length of flight season since 1965. Two climate drivers were used: the accumulated day degrees above 16 °C (ADD16) indicated the potential for migration during the aphid season; the North Atlantic Oscillation (NAO) signalled the severity of the winter before migration took place. 4. All 55 species studied had earlier first flight trends at rate of β = −0·611 ± SE 0·015 days year−1. Of these species, 49% had earlier last flights, but the average species effect appeared relatively stationary (β = −0·010 ± SE 0·022 days year−1). Most species (85%) showed increasing duration of their flight season (β = 0·336 ± SE 0·026 days year−1), even though only 54% increased their log annual count (β = 0·002 ± SE <0·001 year−1). 5. The ADD16 and NAO were shown to drive patterns in aphid phenology in a spatiotemporal context. Early in the year when the first aphids were migrating, the effect of the winter NAO was highly significant. Further into the year, ADD16 was a strong predictor. Latitude had a near linear effect on first flights, whereas longitude produced a generally less-clear effect on all responses. Aphids that are anholocyclic (permanently parthenogenetic) or are monoecious (non-host-alternating) were

  5. Long-term phenological trends, species accumulation rates, aphid traits and climate: five decades of change in migrating aphids.

    PubMed

    Bell, James R; Alderson, Lynda; Izera, Daniela; Kruger, Tracey; Parker, Sue; Pickup, Jon; Shortall, Chris R; Taylor, Mark S; Verrier, Paul; Harrington, Richard

    2015-01-01

    Aphids represent a significant challenge to food production. The Rothamsted Insect Survey (RIS) runs a network of 12·2-m suction-traps throughout the year to collect migrating aphids. In 2014, the RIS celebrated its 50th anniversary. This paper marks that achievement with an extensive spatiotemporal analysis and the provision of the first British annotated checklist of aphids since 1964. Our main aim was to elucidate mechanisms that advance aphid phenology under climate change and explain these using life-history traits. We then highlight emerging pests using accumulation patterns. Linear and nonlinear mixed-effect models estimated the average rate of change per annum and effects of climate on annual counts, first and last flights and length of flight season since 1965. Two climate drivers were used: the accumulated day degrees above 16 °C (ADD16) indicated the potential for migration during the aphid season; the North Atlantic Oscillation (NAO) signalled the severity of the winter before migration took place. All 55 species studied had earlier first flight trends at rate of β = -0·611 ± SE 0·015 days year(-1). Of these species, 49% had earlier last flights, but the average species effect appeared relatively stationary (β = -0·010 ± SE 0·022 days year(-1)). Most species (85%) showed increasing duration of their flight season (β = 0·336 ± SE 0·026 days year(-1)), even though only 54% increased their log annual count (β = 0·002 ± SE <0·001 year(-1)). The ADD16 and NAO were shown to drive patterns in aphid phenology in a spatiotemporal context. Early in the year when the first aphids were migrating, the effect of the winter NAO was highly significant. Further into the year, ADD16 was a strong predictor. Latitude had a near linear effect on first flights, whereas longitude produced a generally less-clear effect on all responses. Aphids that are anholocyclic (permanently parthenogenetic) or are monoecious (non

  6. Inventory and assessment of foliar natural enemies of the soybean aphid (Hemiptera: Aphididae) in South Dakota.

    PubMed

    Hesler, Louis S

    2014-06-01

    Soybean aphid (Aphis glycines Matsumura) (Hemiptera: Aphididae) is a major pest of soybean in northern production regions of North America, and insecticides have been the primary management approach while alternative methods are developed. Knowledge of arthropod natural enemies and their impact on soybean aphid is critical for developing biological control as a management tool. Soybean is a major field crop in South Dakota, but information about its natural enemies and their impact on soybean aphid is lacking. Thus, this study was conducted in field plots in eastern South Dakota during July and August of 2004 and 2005 to characterize foliar-dwelling, arthropod natural enemies of soybean aphid, and it used exclusion techniques to determine impact of natural enemies and ants (Hymenoptera: Formicidae) on soybean aphid densities. In open field plots, weekly soybean aphid densities reached a plateau of several hundred aphids per plant in 2004, and peaked at roughly 400 aphids per plant in 2005. Despite these densities, a relatively high frequency of aphid-infested plants lacked arthropod natural enemies. Lady beetles (Coleoptera: Coccinellidae) were most abundant, peaking at 90 and 52% of all natural enemies sampled in respective years, and Harmonia axyridis Pallas was the most abundant lady beetle. Green lacewings (Neuroptera: Chrysopidae) were abundant in 2005, due mainly to large numbers of their eggs. Abundances of arachnids and coccinellid larvae correlated with soybean aphid densities each year, and chrysopid egg abundance was correlated with aphid density in 2005. Three-week cage treatments of artificially infested soybean plants in 2004 showed that noncaged plants had fewer soybean aphids than caged plants, but abundance of soybean aphid did not differ among open cages and ones that provided partial or total exclusion of natural enemies. In 2005, plants within open cages had fewer soybean aphids than those within cages that excluded natural enemies, and aphid

  7. A highly infective plant-associated bacterium influences reproductive rates in pea aphids

    PubMed Central

    Hendry, Tory A.; Clark, Kelley J.; Baltrus, David A.

    2016-01-01

    Pea aphids, Acyrthosiphon pisum, have the potential to increase reproduction as a defence against pathogens, though how frequently this occurs or how infection with live pathogens influences this response is not well understood. Here we determine the minimum infective dose of an environmentally common bacterium and possible aphid pathogen, Pseudomonas syringae, to determine the likelihood of pathogenic effects to pea aphids. Additionally, we used P. syringae infection to investigate how live pathogens may alter reproductive rates. We found that oral bacterial exposure decreased subsequent survival of aphids in a dose-dependent manner and we estimate that ingestion of less than 10 bacterial cells is sufficient to increase aphid mortality. Pathogen dose was positively related to aphid reproduction. Aphids exposed to low bacterial doses showed decreased, although statistically indistinguishable, fecundity compared to controls. Aphids exposed to high doses reproduced significantly more than low dose treatments and also more, but not significantly so, than controls. These results are consistent with previous studies suggesting that pea aphids may use fecundity compensation as a response to pathogens. Consequently, even low levels of exposure to a common plant-associated bacterium may therefore have significant effects on pea aphid survival and reproduction. PMID:26998321

  8. Aphid facultative symbionts reduce survival of the predatory lady beetle Hippodamia convergens

    PubMed Central

    2014-01-01

    Background Non-essential facultative endosymbionts can provide their hosts with protection from parasites, pathogens, and predators. For example, two facultative bacterial symbionts of the pea aphid (Acyrthosiphon pisum), Serratia symbiotica and Hamiltonella defensa, protect their hosts from parasitism by two species of parasitoid wasp. Previous studies have not explored whether facultative symbionts also play a defensive role against predation in this system. We tested whether feeding on aphids harboring different facultative symbionts affected the fitness of an aphid predator, the lady beetle Hippodamia convergens. Results While these aphid faculative symbionts did not deter lady beetle feeding, they did decrease survival of lady beetle larvae. Lady beetle larvae fed a diet of aphids with facultative symbionts had significantly reduced survival from egg hatching to pupation and therefore had reduced survival to adult emergence. Additionally, lady beetle adults fed aphids with facultative symbionts were significantly heavier than those fed facultative symbiont-free aphids, though development time was not significantly different. Conclusions Aphids reproduce clonally and are often found in large groups. Thus, aphid symbionts, by reducing the fitness of the aphid predator H. convergens, may indirectly defend their hosts’ clonal descendants against predation. These findings highlight the often far-reaching effects that symbionts can have in ecological systems. PMID:24555501

  9. Application of plant growth regulators mitigates chlorotic foliar injury by the black pecan aphid (Hemiptera: Aphididae).

    PubMed

    Cottrell, Ted E; Wood, Bruce W; Ni, Xinzhi

    2010-11-01

    Black pecan aphid, Melanocallis caryaefoliae (Davis) (Hemiptera: Aphididae), feeding elicits localized chlorotic injury to pecan foliage [Carya illinoinensis (Wangenh.) K Koch] and apparent acceleration of leaf senescence and defoliation. The ability of certain plant growth regulators (PGRs) (forchlorfenuron, gibberellic acid and aviglycine) to prevent M. caryaefoliae from triggering pecan leaf chlorosis and senescence-like processes was evaluated on two dates in both 2006 and 2007. Treatments were applied to orchard foliage and used in laboratory leaf-disc bioassays to assess possible reduction in aphid-elicited chlorosis and concomitant effects on aphid mortality and development. Foliage pretreated with forchlorfenuron + gibberellic acid prior to being challenged with aphids resulted in significantly less aphid-elicited chlorosis than did control or aviglycine-treated leaf discs. No PGR affected aphid mortality; however, development time was increased by forchlorfenuron + gibberellic acid in 2006 and by aviglycine + gibberellic acid on one date in 2007. Certain PGRs possess the potential for usage on pecan to protect foliar canopies from M. caryaefoliae via changes in the susceptibility of the host leaf to senescence-like factors being introduced by feeding aphids. This protective effect on host foliage and the associated suppressive effect on development of feeding aphids might also be relevant to pest management programs on other aphid-crop systems in which aphid-elicited chlorosis and senescence-like processes can limit profitability. Published 2010 by John Wiley & Sons, Ltd.

  10. Dropping Behavior in the Pea Aphid (Hemiptera: Aphididae): How Does Environmental Context Affect Antipredator Responses?

    PubMed Central

    Harrison, Katharine V.; Preisser, Evan L.

    2016-01-01

    The pea aphid Acyrthosiphon pisumHarris (Hemiptera: Aphididae) is a phloem-feeding insect whose antipredator defenses include kicking, walking away, and dropping from the plant. Aphid dropping, a risky and energetically costly antipredator behavior, can be increased by the release of aphid alarm pheromone; there is also evidence that insect density and plant health can affect the likelihood of aphids engaging in this behavior. We investigated whether interactions between alarm cues, insect density, and plant health can alter the dropping behavior of aphids in response to an artificial disturbance. The presence of the alarm pheromone E-β-farnesene resulted in a nearly 15-fold increase in aphid dropping behavior; the other two factors, however, did not affect dropping and none of the two- or three-way interactions were significant. This was surprising because aphids affected plant health: production of new plant biomass after 5 d of exposure to high aphid densities was 50% lower than in the control treatment. This research adds to our understanding of the factors affecting aphid antipredator behavior; the fact that neither aphid density nor feeding period impacted dropping may reflect the high energetic costs of this activity and an unwillingness to use it in any but the riskiest situations. PMID:27638950

  11. The stimuli evoking the aerial-righting posture of falling pea aphids.

    PubMed

    Meresman, Yonatan; Ribak, Gal; Weihs, Daniel; Inbar, Moshe

    2014-10-01

    Some wingless insects possess aerial righting reflexes, suggesting that adaptation for controlling body orientation while falling through air could have preceded flight. When threatened by natural enemies, wingless pea aphids (Acyrthosiphon pisum) may drop off their host plant and assume a stereotypic posture that rotates them in midair to land on their feet. The sensory information triggering aphids to assume this posture has so far been unknown. We subjected aphids to a series of tests, isolating the sensory cues experienced during free-fall. Falling aphids assumed the righting posture and landed upright irrespective of whether the experiments were carried out in the light or in complete darkness. Detachment of the tarsi from the substrate triggered the aphids to assume the posture rapidly, but only for a brief period. Rotation (mainly roll and yaw) of the body in air, in the light, caused aphids to assume the posture and remain in it throughout rotation. In contrast, aphids rotated in the dark did not respond. Acceleration associated with falling or airflow over the body per se did not trigger the posture. However, sensing motion relative to air heightened the aphids' responsiveness to rotation in the light. These results suggest that the righting posture of aphids is triggered by a tarsal reflex, but, once the aphid is airborne, vision and a sense of motion relative to air can augment the response. Hence, aerial righting in a wingless insect could have emerged as a basic tarsal response and developed further to include secondary sensory cues typical of falling.

  12. Tritrophic interactions among Macrosiphum euphorbiae aphids, their host plants and endosymbionts: investigation by a proteomic approach.

    PubMed

    Francis, F; Guillonneau, F; Leprince, P; De Pauw, E; Haubruge, E; Jia, L; Goggin, F L

    2010-06-01

    The Mi-1.2 gene in tomato confers resistance against certain clones of the potato aphid (Macrosiphum euphorbiae). This study used 2D-DIGE coupled with protein identification by MALDI-TOF-MS to compare the proteome patterns of avirulent and semivirulent potato aphids and their bacterial endosymbionts on resistant (Mi-1.2+) and susceptible (Mi-1.2-) tomato lines. Avirulent aphids had low survival on resistant plants, whereas the semivirulent clone could colonize these plants. Eighty-two protein spots showed significant quantitative differences among the four treatment groups, and of these, 48 could be assigned putative identities. Numerous structural proteins and enzymes associated with primary metabolism were more abundant in the semivirulent than in the avirulent aphid clone. Several proteins were also up-regulated in semivirulent aphids when they were transferred from susceptible to resistant plants. Nearly 25% of the differentially regulated proteins originated from aphid endosymbionts and not the aphid itself. Six were assigned to the primary endosymbiont Buchnera aphidicola, and 5 appeared to be derived from a Rickettsia-like secondary symbiont. These results indicate that symbiont expression patterns differ between aphid clones with differing levels of virulence, and are influenced by the aphids' host plant. Potentially, symbionts may contribute to differential adaptation of aphids to host plant resistance.

  13. High susceptibility of Bt maize to aphids enhances the performance of parasitoids of lepidopteran pests.

    PubMed

    Faria, Cristina A; Wäckers, Felix L; Pritchard, Jeremy; Barrett, David A; Turlings, Ted C J

    2007-07-11

    Concerns about possible undesired environmental effects of transgenic crops have prompted numerous evaluations of such crops. So-called Bt crops receive particular attention because they carry bacteria-derived genes coding for insecticidal proteins that might negatively affect non-target arthropods. Here we show a remarkable positive effect of Bt maize on the performance of the corn leaf aphid Rhopalosiphum maidis, which in turn enhanced the performance of parasitic wasps that feed on aphid honeydew. Within five out of six pairs that were evaluated, transgenic maize lines were significantly more susceptible to aphids than their near-isogenic equivalents, with the remaining pair being equally susceptible. The aphids feed from the phloem sieve element content and analyses of this sap in selected maize lines revealed marginally, but significantly higher amino acid levels in Bt maize, which might partially explain the observed increased aphid performance. Larger colony densities of aphids on Bt plants resulted in an increased production of honeydew that can be used as food by beneficial insects. Indeed, Cotesia marginiventris, a parasitoid of lepidopteran pests, lived longer and parasitized more pest caterpillars in the presence of aphid-infested Bt maize than in the presence of aphid-infested isogenic maize. Hence, depending on aphid pest thresholds, the observed increased susceptibility of Bt maize to aphids may be either a welcome or an undesirable side effect.

  14. Within-plant distribution of cotton aphid (Hemiptera: Aphididae) in cotton cultivars with colored fibers.

    PubMed

    Fernandes, Francisco S; Ramalho, Francisco S; Malaquias, José B; Nascimento Junior, José L; Correia, Ezequias T; Zanuncio, José C

    2012-09-01

    We describe the vertical and horizontal distribution of the cotton aphid Aphis gossypii Glover within a cotton plant in two cotton (Gossypium hirsutum Linnaeus) cultivars (BRS Safira and BRS Rubí) with colored fiber over the time. Measurements of aphid population dynamics and distribution in the cotton plants were recorded in intervals of seven days. The number of apterous or alate aphids and their specific locations were recorded, using as a reference point the location of nodes on the mainstem of the plant and also those on the leaves present on branches and fruit structures. The number of apterous aphids found on the cultivar BRS Safira (56,515 aphids) was greater than that found on BRS Rubí (50,537 aphids). There was no significant difference between the number of alate aphids found on the cultivars BRS Safira (365 aphids/plant) and BRS Rubí (477 aphids/plant). There were interactions between cotton cultivar and plant age, between plant region and plant age, and between cultivar and plant region for apterous aphids. The results of this study are of great importance in improving control strategies for A. gossypii in the naturally-colored cotton cultivars BRS Safira and BRS Rubí.

  15. Myzus persicae (green peach aphid) salivary components induce defence responses in Arabidopsis thaliana.

    PubMed

    De Vos, Martin; Jander, Georg

    2009-11-01

    Myzus persicae (green peach aphid) feeding on Arabidopsis thaliana induces a defence response, quantified as reduced aphid progeny production, in infested leaves but not in other parts of the plant. Similarly, infiltration of aphid saliva into Arabidopsis leaves causes only a local increase in aphid resistance. Further characterization of the defence-eliciting salivary components indicates that Arabidopsis recognizes a proteinaceous elicitor with a size between 3 and 10 kD. Genetic analysis using well-characterized Arabidopsis mutants shows that saliva-induced resistance against M. persicae is independent of the known defence signalling pathways involving salicylic acid, jasmonate and ethylene. Among 78 Arabidopsis genes that were induced by aphid saliva infiltration, 52 had been identified previously as aphid-induced, but few are responsive to the well-known plant defence signalling molecules salicylic acid and jasmonate. Quantitative PCR analyses confirm expression of saliva-induced genes. In particular, expression of a set of O-methyltransferases, which may be involved in the synthesis of aphid-repellent glucosinolates, was significantly up-regulated by both M. persicae feeding and treatment with aphid saliva. However, this did not correlate with increased production of 4-methoxyindol-3-ylmethylglucosinolate, suggesting that aphid salivary components trigger an Arabidopsis defence response that is independent of this aphid-deterrent glucosinolate.

  16. Molecular characterization of aphid resistance in black raspberry germplasm

    USDA-ARS?s Scientific Manuscript database

    Black raspberry is a minor but lucrative crop with most of the acreage in the U.S. found in Oregon. Rapid decline of plantings results from virus infection vectored by the North American large raspberry aphid and is the most limiting factor for growing black raspberry. Existing cultivars are suscept...

  17. Catalog of the Aphid Genera Described from the New World

    USDA-ARS?s Scientific Manuscript database

    This manuscript presents a synthesis and catalogue of the genera of New World aphids (sensu stricto) from 1758 to 2004. It includes information on 215 generic and subgeneric names, type localities, bibliographic information, etymology, as well as synonymic and other nomenclatural data. Two nomencl...

  18. Sugarcane aphid spatial distribution in grain sorghum fields

    USDA-ARS?s Scientific Manuscript database

    Sorghum is an important summer grain crop in the United States. In 2014, the U.S. produced 432 million bushels of sorghum valued at $1.67 billion on more than 6 million acres. The sugarcane aphid, Melanaphis sacchari (Zehntner), was discovered in damaging numbers in grain sorghum, Sorghum bicolor ...

  19. Biotype differences for resistance to Russian wheat aphid in barley

    USDA-ARS?s Scientific Manuscript database

    Russian wheat aphid (RWA) is a worldwide insect pest of barley, causing crop losses each year. Previously identified resistant barley lines do not show variable reactions to the eight USA RWA biotypes identified by wheat reactions. However, additional RWA isolates have been identified outside the ...

  20. Ladybird-induced life-history changes in aphids

    PubMed Central

    Dixon, A. F. G.; Agarwala, B. K.

    1999-01-01

    Predator-mediated plasticity in the morphology, life history and behaviour of prey organisms has been widely reported in freshwater ecosystems. Although clearly adaptive, similar responses have only recently been reported for terrestrial organisms. This is surprising as aphids are polyphenic and develop very rapidly compared with their predators and often produce very large colonies, which are attractive to predators. Therefore, one might expect terrestrial organisms like aphids to show a facultative change in their development in response to the presence of predators and other results have confirmed this. The results presented below indicate that the pea aphid responded to the tracks left by ladybird larvae by producing a greater proportion of winged offspring, which avoid the impending increased risk of predation by dispersing. Associated with this was a short-term increase in activity and reduction in fecundity. The black bean and vetch aphids, which are afforded some protection from ladybirds because they are ant attended and/or unpalatable, did not respond in this way to the presence of ladybird larvae.

  1. Timing of aerial surveys for the balsam woolly aphid

    Treesearch

    W.J. Buckhorn; Paul G. Lauterbach

    1957-01-01

    An outbreak of the balsam woolly aphid (Chermes piceae Ratz.) is damaging and killing Pacific silver fir, subalpine fir, and grand fir extensively in western Washington and Oregon. It is most serious in southern Washington where an outbreak on Pacific silver fir was discovered in 1954. Since effective methods for controlling this insect under...

  2. Sugarcane aphid resistance in sorghum and a host range

    USDA-ARS?s Scientific Manuscript database

    The sugarcane aphid (SCA), Melanaphis sacchari, has been present in the United States primarily on sugarcane in Florida, Hawaii, and Louisiana until 2013 where it was found on grain sorghum near Beaumont, Texas. Since 2013, the SCA has been rapidly spreading and overwintering. Depending on the plant...

  3. Sugarcane aphid in Oklahoma: Responding to a new pest

    USDA-ARS?s Scientific Manuscript database

    The sugarcane aphid (SCA) was first found in Oklahoma in 2013, and quickly became a major threat to grain sorghum production. Scientists at Oklahoma State University and the USDA's Wheat, Peanut and Other Field Crops Research Lab in Stillwater, working with cooperators in other sorghum producing st...

  4. Presence of the Aphid, Chaetosiphon fragaefolii, on Strawberry in Argentina

    PubMed Central

    Cédola, Claudia; Grecob, Nancy

    2010-01-01

    Seasonal abundance of the strawberry aphid complex under different agronomic practices in the outskirts of La Plata, Argentina was studied on strawberry, Fragaria x ananassa Duchesne (Rosales: Rosaceae). Aphid densities were low in strawberry fields in which insecticides and fungicides were used. In addition to Aphis gossypii, Aphis fabae, Mysus persicae and Macrosiphum euphorbiae, the aphid, Chaetosiphon fragaefolii (Cockerell) (Homoptera: Aphididae), was recorded for the first time in this horticultural area. Life history and some demographic parameters were calculated for C. fragaefolii. The mean duration of nymphal stages was 10.44 days, the oviposition period was 11.8 days, and the mean number of nymph/female/day was 2.4 ± 0.3. Demographic parameters analyzed included the net reproductive rate Ro = 14.55 ± 0.096 nymph/female, generation time T=16.91 ± 0.035 days, and the intrinsic rate of increase rm = 0.158 ± (0.004). No parasites were found associated with C. fragaefolli. The pathogenic fungus, Entomophthora planchoniana Cornu (Zygomycetes: Entomophthorales) was the main mortality factor. Although aphids are not the main pests in strawberry fields, C. fragaefolii can be a serious problem because it can transmit several virus diseases of strawberry. Greater knowledge of life history traits and mortality factors of this species is needed in order to design appropriate control strategies. PMID:20569141

  5. Predicting potential ecological impact of soybean aphid biological control introductions

    USDA-ARS?s Scientific Manuscript database

    The soybean aphid, APHIS GLYCINES, was first reported in the US in 2000; since then, it has spread to 22 states, putting >24 million hectares of soybean at risk. In China, APHIS GLYCINES rarely reaches damaging levels and has a diverse complex of predators and parasitoids. In the US, parasitoids are...

  6. Relative susceptibility of pecan germplasm to blackmargined aphid

    USDA-ARS?s Scientific Manuscript database

    The blackmargined aphid, Monellia caryella (Fitch), is an important phytophage in the pecan, Carya illinoinensis (Wangenh.) K. Koch, agroecosystem where it often is treated with insecticide. Pecan cultivars released by the USDA Pecan Breeding Program vary in susceptibility and risk of damage from t...

  7. The balsam woolly aphid problem in Oregon and Washington.

    Treesearch

    Norman E. Johnson; Kenneth H. Wright

    1957-01-01

    A European insect, commonly called the balsam woolly aphid or chermes, is damaging and killing true fir (Abies) in western Oregon and Washington. Some 350,000 acres are known to be infested. Tree killing has reached the point where concerted action is needed. Major salvage plans are being developed by private, state, and federal forest managers to...

  8. A guide to the winged aphids (Homoptera) of Costa Rica.

    PubMed

    Voegtlin, David; Villalobos, William; Sánchez, Marco Vinicio; Saborio-R, Guido; Rivera, Carmen

    2003-05-01

    This guide is a compilation of limited morphological and biological information on the winged morphs of 60 species of aphids that have been collected in Costa Rica. It should not be viewed as a definitive taxonomic treatise on the aphids of Costa Rica, rather it is a tool that can be used to assist in research on the biology, host plant relationships, taxonomy, and virus transmission capabilities of aphids. Each species is covered in an identical manner. Morphological and biological information is provided in both Spanish and English as well as photographs of slide mounted specimens. Keys are provided to help the user in identifying the species. Most of the specimens examined were taken in traps associated with epidemiological studies. Limited field collecting has generated host records and these have been added to a list of the aphids of Central America that was compiled by Pamela Anderson and appended in the guide with her permission. The authors hope that this book will be useful to entomologists in Costa Rica and Central America.

  9. Elevated Carbon Dioxide Concentration Reduces Alarm Signaling in Aphids.

    PubMed

    Boullis, Antoine; Fassotte, Bérénice; Sarles, Landry; Lognay, Georges; Heuskin, Stéphanie; Vanderplanck, Maryse; Bartram, Stefan; Haubruge, Eric; Francis, Frédéric; Verheggen, François J

    2017-02-01

    Insects often rely on olfaction to communicate with conspecifics. While the chemical language of insects has been deciphered in recent decades, few studies have assessed how changes in atmospheric greenhouse gas concentrations might impact pheromonal communication in insects. Here, we hypothesize that changes in the concentration of atmospheric carbon dioxide affect the whole dynamics of alarm signaling in aphids, including: (1) the production of the active compound (E)-β-farnesene (Eβf), (2) emission behavior when under attack, (3) perception by the olfactory apparatus, and (4) the escape response. We reared two strains of the pea aphid, Acyrthosiphon pisum, under ambient and elevated CO2 concentrations over several generations. We found that an increase in CO2 concentration reduced the production (i.e., individual content) and emission (released under predation events) of Eβf. While no difference in Eβf neuronal perception was observed, we found that an increase in CO2 strongly reduced the escape behavior expressed by an aphid colony following exposure to natural doses of alarm pheromone. In conclusion, our results confirm that changes to greenhouse gases impact chemical communication in the pea aphid, and could potentially have a cascade effect on interactions with higher trophic levels.

  10. US EPA, Pesticide Product Label, FULEX APHID SMOKE ...

    EPA Pesticide Factsheets

    2011-04-14

    ... 1 .·"uti"" ... u .... t' ;1.~;liu .... t ~1·t·f·llhlJu .... • aphid .... 'I·il ... ~!I('I'!)t·f· ... , lcI,all \\\\ ltil,' Iii.· ... all.: ·,,11111 10-.11 'i.·I· .... W"ight - :!,fi:> 0.'. ...

  11. Differential susceptibility of white fir provenances to balsam twig aphid

    Treesearch

    George T. Ferrell

    1989-01-01

    Susceptibility of Oregon, California, Nevada, Utah, and Arizona provenances of white fir (Abies concolor [Gord. & Glend.] Lindl.) to crown injury caused by balsam twig aphid (Mindarus abietinus Koch.) was assessed in an experimental plantation in the central Sierra Nevada in California. Bud phenology was observed to explore...

  12. Clytostoma callistegioides (Bignoniaceae) wax extract with activity on aphid settling.

    PubMed

    Castillo, Lucía; Díaz, Martina; González-Coloma, Azucena; González, Andrés; Alonso-Paz, Eduardo; Bassagoda, María Julia; Rossini, Carmen

    2010-12-01

    A bioassay-guided fractionation of leaf extracts from Clytostoma callistegioides (Cham.) Bureau ex Griseb. (Bignoniaceae) led to isolation of a natural mixture of four fatty acids with anti-insect activity against aphids. The compounds were identified by GC-MS as palmitic, stearic, linoleic and linolenic acids and quantified as their methyl esters. The anti-aphid activity of the natural mixture was traced to linolenic and linoleic acids, as shown by the settling inhibition activity of synthetic samples. Interestingly, the saturated acids (palmitic and stearic) tested alone stimulated settling on one of the tested aphids (Myzus persicae), but not on the other tested species (Rhopalosiphum padi). Although ubiquitous, none of these free acids have been previously reported in this Bignoniaceae species. The leaf surface chemistry, which is likely involved in modulating aphid settling behavior, was further investigated for the occurrence of lipophilic substances by histochemical staining. Short, stalked glandular trichomes, previously undescribed for this species, stained with osmium tetroxide and Sudan III, suggesting that the secretion of the defensive acids is related to these surface trichomes. Copyright © 2010 Elsevier Ltd. All rights reserved.

  13. Genetic characterization of an emerging aphid pest in sorghum

    USDA-ARS?s Scientific Manuscript database

    On July 2013, a new aphid in sorghum was observed in Texas. By the end of November the area of influence of this emergent pest included Texas, Oklahoma, Louisiana, and Florida. Sorghum fields in these States sustained considerable losses. In some locations, yield losses of 33% to 50% were observe...

  14. Bird cherry-oat aphid: do we have resistance?

    USDA-ARS?s Scientific Manuscript database

    Bird cherry-oat aphid (BCOA), Rhopalosiphum padi (L.), is a highly efficient, non-propagative, persistent vector of the phloem limited leutovirus BYD-PAV. BYD is the most important viral disease of cereal grains in the world and PAV is the most prevalent strain of BYD in North America. Not all BCO...

  15. Effects of thiamethoxam seed treatments on soybean aphid (Hemiptera: Aphididae) feeding behavior.

    PubMed

    Stamm, M D; Heng-Moss, T M; Baxendale, F P; Reese, J C; Siegfried, B D; Hunt, T E; Gaussoin, R E; Blankenship, E E

    2013-12-01

    Since its discovery in North America in 2000, the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), has rapidly become an important pest of soybean [Glycine max (L.) Merrill], sometimes resulting in significant yield losses. Previous research has documented the toxicity of neonicotinoid seed treatments to soybean aphids, but control under field conditions has been inconsistent. Imidacloprid, a popular neonicotinoid insecticide, has been shown to exhibit antifeedant effects on aphids. Antifeedant activity has not been demonstrated for other neonicotinoids, including thiamethoxam. This research investigated the effects of a thiamethoxam seed treatment on soybean aphid feeding behavior by using electronic penetration graphs (EPG) to visualize stylet penetration behavior. Soybean aphid feeding behavior was assessed for 9 h on thiamethoxam-treated and untreated soybeans (V2 and V4 stages). Because results were inconclusive from initial experiments, a study was conducted to document the effects of thiamethoxam-treated soybeans on soybean aphid survival. The seed treatment was shown to negatively affect aphid survival at 4, 8, and 11 d after aphid introduction. A subsequent EPG study then was designed to document soybean aphid feeding behavior for 15 h, after an initial exposure of 9 h to thiamethoxam-treated soybeans. In this study, the exposed aphids exhibited significant differences in feeding behavior compared with those aphids feeding on untreated soybeans. Soybean aphids on thiamethoxam-treated soybeans spent significantly less time feeding in the sieve element phase, with a greater duration of nonprobing events. These studies suggest soybean aphids are unable to ingest phloem sap, which may be another important element in seed treatment protection.

  16. Contribution of Noncolonizing Aphids to Potato Virus Y Prevalence in Potato in Idaho.

    PubMed

    Mondal, Shaonpius; Wenninger, Erik J; Hutchinson, Pamela J S; Weibe, Monica A; Eigenbrode, Sanford D; Bosque-Pérez, Nilsa A

    2016-09-30

    Potato virus Y (PVY) is a major concern for potato production in the United States given its impact on both crop quality and yield. Although green peach aphid, Myzus persicae (Sulzer), is the most efficient PVY vector, it may be less abundant in potato-growing areas of Idaho relative to non-potato-colonizing aphid vectors of PVY that may disperse from nearby cereal fields and other crops. A field study was conducted during 2012-2013 to examine if noncolonizing aphids disperse to nearby potato fields as cereal crops dry down before harvest. The aphid fauna was sampled weekly in four different potato fields in south-central and southeastern Idaho using yellow sticky traps and yellow pan traps. Potato fields were chosen with an adjacent cereal field such that the prevailing westerly wind would facilitate aphid dispersal from cereal fields to potato. Non-potato-colonizing aphids sampled included 10 cereal aphid species, the most abundant of which were Rhopalosiphum padi L. and Metopolophium dirhodum (Walker). More than 35 species from noncereal hosts also were found. Overall, green peach aphid abundance was relatively low, ranging from 0.5-2.5% of the total aphid capture between years and among fields. In both years and all locations, cereal aphid abundance peaked in mid- to late July (cereal ripening stage) and decreased thereafter as cereal crops dried. PVY prevalence in the potato fields increased following these increases in aphid abundance. This study suggests that cereal aphids and other noncolonizing aphids are important contributors to PVY prevalence in potato in southern Idaho. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Ants Learn Aphid Species as Mutualistic Partners: Is the Learning Behavior Species-Specific?

    PubMed

    Hayashi, Masayuki; Nakamuta, Kiyoshi; Nomura, Masashi

    2015-12-01

    In ant-aphid associations, many aphid species provide ants with honeydew and are tended by ants, whereas others are never tended and are frequently preyed upon by ants. In these relationships, ants must have the ability to discriminate among aphid species, with mutualistic aphids being accepted as partners rather than prey. Although ants reportedly use cuticular hydrocarbons (CHCs) of aphids to differentiate between mutualistic and non-mutualistic species, it is unclear whether the ability to recognize mutualistic aphid species as partners is innate or involves learning. Therefore, we tested whether aphid recognition by ants depends on learning, and whether the learning behavior is species-specific. When workers of the ant Tetramorium tsushimae had previously tended the cowpea aphid, Aphis craccivora, they were less aggressive toward this species. In addition, ants also reduced their aggressiveness toward another mutualistic aphid species, Aphis fabae, after tending A. craccivora, whereas ants remained aggressive toward the non-mutualistic aphid, Acyrthosiphon pisum, regardless of whether or not they had previous experience in tending A. craccivora. When ants were offered glass dummies treated with CHCs of these aphid species, ants that had tended A. craccivora displayed reduced aggression toward CHCs of A. craccivora and A. fabae. Chemical analyses showed the similarity of the CHC profiles between A. craccivora and A. fabae but not with A. pisum. These results suggest that aphid recognition of ants involves learning, and that the learning behavior may not be species-specific because of the similarity of CHCs between different aphid species with which they form mutualisms.

  18. Host Plants Indirectly Influence Plant Virus Transmission by Altering Gut Cysteine Protease Activity of Aphid Vectors.

    PubMed

    Pinheiro, Patricia V; Ghanim, Murad; Alexander, Mariko; Rebelo, Ana Rita; Santos, Rogerio S; Orsburn, Benjamin C; Gray, Stewart; Cilia, Michelle

    2017-04-01

    The green peach aphid, Myzus persicae, is a vector of the Potato leafroll virus (PLRV, Luteoviridae), transmitted exclusively by aphids in a circulative manner. PLRV transmission efficiency was significantly reduced when a clonal lineage of M. persicae was reared on turnip as compared with the weed physalis, and this was a transient effect caused by a host-switch response. A trend of higher PLRV titer in physalis-reared aphids as compared with turnip-reared aphids was observed at 24 h and 72 h after virus acquisition. The major difference in the proteomes of these aphids was the up-regulation of predicted lysosomal enzymes, in particular the cysteine protease cathepsin B (cathB), in aphids reared on turnip. The aphid midgut is the site of PLRV acquisition, and cathB and PLRV localization were starkly different in midguts of the aphids reared on the two host plants. In viruliferous aphids that were reared on turnip, there was near complete colocalization of cathB and PLRV at the cell membranes, which was not observed in physalis-reared aphids. Chemical inhibition of cathB restored the ability of aphids reared on turnip to transmit PLRV in a dose-dependent manner, showing that the increased activity of cathB and other cysteine proteases at the cell membrane indirectly decreased virus transmission by aphids. Understanding how the host plant influences virus transmission by aphids is critical for growers to manage the spread of virus among field crops. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. Contribution of Noncolonizing Aphids to Potato Virus Y Prevalence in Potato in Idaho.

    PubMed

    Mondal, Shaonpius; Wenninger, Erik J; Hutchinson, Pamela J S; Weibe, Monica A; Eigenbrode, Sanford D; Bosque-Pérez, Nilsa A

    2016-12-01

    Potato virus Y (PVY) is a major concern for potato production in the United States given its impact on both crop quality and yield. Although green peach aphid, Myzus persicae (Sulzer), is the most efficient PVY vector, it may be less abundant in potato-growing areas of Idaho relative to non-potato-colonizing aphid vectors of PVY that may disperse from nearby cereal fields and other crops. A field study was conducted during 2012-2013 to examine if noncolonizing aphids disperse to nearby potato fields as cereal crops dry down before harvest. The aphid fauna was sampled weekly in four different potato fields in south-central and southeastern Idaho using yellow sticky traps and yellow pan traps. Potato fields were chosen with an adjacent cereal field such that the prevailing westerly wind would facilitate aphid dispersal from cereal fields to potato. Non-potato-colonizing aphids sampled included 10 cereal aphid species, the most abundant of which were Rhopalosiphum padi L. and Metopolophium dirhodum (Walker). More than 35 species from noncereal hosts also were found. Overall, green peach aphid abundance was relatively low, ranging from 0.5-2.5% of the total aphid capture between years and among fields. In both years and all locations, cereal aphid abundance peaked in mid- to late July (cereal ripening stage) and decreased thereafter as cereal crops dried. PVY prevalence in the potato fields increased following these increases in aphid abundance. This study suggests that cereal aphids and other noncolonizing aphids are important contributors to PVY prevalence in potato in southern Idaho. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Diversification of genes for carotenoid biosynthesis in aphids following an ancient transfer from a fungus.

    PubMed

    Nováková, Eva; Moran, Nancy A

    2012-01-01

    The pea aphid genome was recently found to harbor genes for carotenoid biosynthesis, reflecting an ancestral transfer from a fungus. To explore the evolution of the carotene desaturase gene family within aphids, sequences were retrieved from a set of 34 aphid species representing numerous deeply diverging lineages of aphids and analyzed together with fungal sequences retrieved from databases. All aphids have at least one copy of this gene and some aphid species have up to seven, whereas fungal genomes consistently have a single copy. The closest relatives of aphids, adelgids, also have carotene desaturase; these sequences are most closely related to those from aphids, supporting a shared origin from a fungal to insect transfer predating the divergence of adelgids and aphids. Likewise, all aphids, and adelgids, have carotenoid profiles that are consistent with their biosynthesis using the acquired genes of fungal origin rather than derivation from food plants. The carotene desaturase was acquired from a fungal species outside of Ascomycota or Basidiomycota and closest to Mucoromycotina among sequences available in databases. In aphids, an ongoing pattern of gene duplication is indicated by the presence of both anciently and recently diverged paralogs within genomes and by the presence of a high frequency of pseudogenes that appear to be recently inactivated. Recombination among paralogs is evident, making analyses of patterns of selection difficult, but tests of selection for a nonrecombining region indicates that duplications tend to be followed by bouts of positive selection. Species of Macrosiphini, which often show color polymorphisms, typically have a larger number of desaturase copies relative to other species sampled in the study. These results indicate that aphid evolution has been accompanied by ongoing evolution of carotenogenic genes, which have undergone duplication, recombination, and occasional positive selection to yield a wide variety of carotenoid

  1. Genetic mapping revealed two loci for soybean aphid resistance in PI 567301B.

    PubMed

    Jun, Tae-Hwan; Rouf Mian, M A; Michel, Andrew P

    2012-01-01

    The soybean aphid (Aphis glycines Matsumura) is the most damaging insect pest of soybean [Glycine max (L.) Merr.] in North America. New soybean aphid biotypes have been evolving quickly and at least three confirmed biotypes have been reported in USA. These biotypes are capable of defeating most known aphid resistant soybean genes indicating the need for identification of new genes. Plant Introduction (PI) 567301B was earlier identified to have antixenosis resistance against biotype 1 and 2 of the soybean aphid. Two hundred and three F(7:9) recombinant inbred lines (RILs) developed from a cross of soybean aphid susceptible cultivar Wyandot and resistant PI 567301B were used for mapping aphid resistance genes using the quantitative trait loci (QTL) mapping approach. A subset of 94 RILs and 516 polymorphic SNP makers were used to construct a genome-wide molecular linkage map. Two candidate QTL regions for aphid resistance were identified on this linkage map. Fine mapping of the QTL regions was conducted with SSR markers using all 203 RILs. A major gene on chromosome 13 was mapped near the previously identified Rag2 gene. However, an earlier study revealed that the detached leaves of PI 567301B had no resistance against the soybean aphids while the detached leaves of PI 243540 (source of Rag2) maintained aphid resistance. These results and the earlier finding that PI 243540 showed antibiosis resistance and PI 567301B showed antixenosis type resistance, indicating that the aphid resistances in the two PIs are not controlled by the same gene. Thus, we have mapped a new gene near the Rag2 locus for soybean aphid resistance that should be useful in breeding for new aphid-resistant soybean cultivars. Molecular markers closely linked to this gene are available for marker-assisted breeding. Also, the minor locus found on chromosome 8 represents the first reported soybean aphid-resistant locus on this chromosome.

  2. Circulative Nonpropagative Aphid Transmission of Nanoviruses: an Oversimplified View

    PubMed Central

    Sicard, Anne; Zeddam, Jean-Louis; Yvon, Michel; Michalakis, Yannis; Gutiérrez, Serafin

    2015-01-01

    ABSTRACT Plant virus species of the family Nanoviridae have segmented genomes with the highest known number of segments encapsidated individually. They thus likely represent the most extreme case of the so-called multipartite, or multicomponent, viruses. All species of the family are believed to be transmitted in a circulative nonpropagative manner by aphid vectors, meaning that the virus simply crosses cellular barriers within the aphid body, from the gut to the salivary glands, without replicating or even expressing any of its genes. However, this assumption is largely based on analogy with the transmission of other plant viruses, such as geminiviruses or luteoviruses, and the details of the molecular and cellular interactions between aphids and nanoviruses are poorly investigated. When comparing the relative frequencies of the eight genome segments in populations of the species Faba bean necrotic stunt virus (FBNSV) (genus Nanovirus) within host plants and within aphid vectors fed on these plants, we unexpectedly found evidence of reproducible changes in the frequencies of some specific segments. We further show that these changes occur within the gut during early stages of the virus cycle in the aphid and not later, when the virus is translocated into the salivary glands. This peculiar observation, which was similarly confirmed in three aphid vector species, Acyrthosiphon pisum, Aphis craccivora, and Myzus persicae, calls for revisiting of the mechanisms of nanovirus transmission. It reveals an unexpected intimate interaction that may not fit the canonical circulative nonpropagative transmission. IMPORTANCE A specific mode of interaction between viruses and arthropod vectors has been extensively described in plant viruses in the three families Luteoviridae, Geminiviridae, and Nanoviridae, but never in arboviruses of animals. This so-called circulative nonpropagative transmission contrasts with the classical biological transmission of animal arboviruses in that

  3. [Population dynamics and control techniques of aphids on honeysuckle].

    PubMed

    Sun, Ying; Xue, Ming; Zhang, Xiao; Zhao, Hai-Peng; Li, Zhao-Xia

    2013-11-01

    The objective of this study is to define the population dynamics of Semiaphis heraclei in the main-producing district of Lonicera japonica in Shandong, and screen for highly efficient, safety control technique. Through fixed field investigation, we tested the toxicity of eight kinds of insecticides by using dipping methods, and carried out the field experiment. The results showed that the aphids' emergence peak appeared in May. The aphids on the Sijihua variety of L. japonica was more susceptible and the peak was also seven days earlier than Damao variety of L. japonica. The aphid populations on Sijihua were 1 fold than those on the Daomao in happened peak. Comparing the eight kinds of insecticides, the LC50 of lambda-cyhaothrin, abamectin, imidacloprid and pyrethrin to wingless aphids were 1.494, 1.690, 2.840, 2.861 mg x L(-1), respectively, whose toxicity were higher, the toxicity of matrine, pymetrozine and azadirachtin were also high. The field efficacy trials indicated that during the period of aphids occurred, 25% imidacloprid wettable powder, 1.8% abamectin missible oil, 2.5% lambda-cyhaothrin missible oil, 25% pymetrozine wettable powder, 5% pyrethrin missible oil, 1% matrine water aqua were sprayed at concentrations of 20,000, 2,000, 2,500, 5,000, 500 and 50 times, respectively,the control effect achieved 91.69%, 98.90%, 96.18%, 95.06%, 99.24%, 90.10%, respectively, after 5 days. During the growing period of L. japonica in spring, application of thiamethoxam, thiacloprid, pymetrozine and imidacloprid, all of the control effect against aphids achieved above 98.88% after 50 days. The result indicated that May was the S. heraclei Takahashi's emergence peak in Pingyi, Shandong. The efficient safety and environmentally friendly insecticides by spraying and systemic insecticide of pymetrozine and imidacloprid by root application were all efficient controlled aphids. These insecticides were long for controlling S. heraclei Takahashi and worthy of being widely

  4. Plant-Generated Artificial Small RNAs Mediated Aphid Resistance

    PubMed Central

    Wang, Guiling; Yang, Kun; Wang, Yu; Niu, Libo; Chen, Xiaoying; Fang, Rongxiang

    2014-01-01

    Background RNA silencing is an important mechanism for regulation of endogenous gene expression and defense against genomic intruders in plants. This natural defense system was adopted to generate virus-resistant plants even before the mechanism of RNA silencing was unveiled. With the clarification of that mechanism, transgenic antiviral plants were developed that expressed artificial virus-specific hairpin RNAs (hpRNAs) or microRNAs (amiRNAs) in host plants. Previous works also showed that plant-mediated RNA silencing technology could be a practical method for constructing insect-resistant plants by expressing hpRNAs targeting essential genes of insects. Methodology/Principal findings In this study, we chose aphid Myzus persicae of order Hemiptera as a target insect. To screen for aphid genes vulnerable to attack by plant-mediated RNA silencing to establish plant aphid resistance, we selected nine genes of M. persicae as silencing targets, and constructed their hpRNA-expressing vectors. For the acetylcholinesterase 2 coding gene (MpAChE2), two amiRNA-expressing vectors were also constructed. The vectors were transformed into tobacco plants (Nicotiana tabacum cv. Xanti). Insect challenge assays showed that most of the transgenic plants gained aphid resistance, among which those expressing hpRNAs targeting V-type proton ATPase subunit E-like (V-ATPaseE) or tubulin folding cofactor D (TBCD) genes displayed stronger aphicidal activity. The transgenic plants expressing amiRNAs targeting two different sites in the MpAChE2 gene exhibited better aphid resistance than the plants expressing MpAChE2-specific hpRNA. Conclusions/Significance Our results indicated that plant-mediated insect-RNA silencing might be an effective way to develop plants resistant to insects with piercing-sucking mouthparts, and both the selection of vulnerable target genes and the biogenetic type of the small RNAs were crucial for the effectiveness of aphid control. The expression of insect

  5. Ant Mimicry by an Aphid Parasitoid, Lysiphlebus fabarum

    PubMed Central

    Rasekh, Arash; Michaud, J.P.; Kharazi-Pakdel, Aziz; Allahyari, Hossein

    2010-01-01

    In Iran, Lysiphlebus fabarum (Marshall) (Hymenoptera: Braconidae: Aphidiinae) is a uniparental parasitoid of the black bean aphid, Aphis fabae Scopoli (Hemiptera: Aphididae), that possesses various highly evolved adaptations for foraging within ant-tended aphid colonies. Direct observations and video recordings were used to analyze the behavior of individual females foraging for A. fabae on bean leaf disks in open arenas in the laboratory. Females exploited aphids as hosts and as a source of food, allocating within-patch time as follows: resting - 10.4%, grooming - 8.2%, searching - 11.5%, antennation (host recognition) - 7.5%, antennation (honeydew solicitation mimicking ants) - 31.9%, abdominal bending (attack preparation) 19.7%, probing with the ovipositor (attack) - 10.8%. The mean handling time for each aphid encountered was 2.0 ± 0.5 min. Females encountered an average of 47.4 ± 6.4 aphids per hour, but laid only 1.2 eggs per hour. The ovipositor insertion time for parasitism ranged from 2 sec to longer than a minute, but most insertions did not result in an egg being laid. A. fabae defensive behaviors included kicking, raising and swiveling the body, and attempts to smear the attacker with cornicle secretions, sometimes with lethal results. Food deprivation for 4–6 h prior to testing increased the frequency of ant mimcry by L. fabarum. Females also used ant-like antennation to reduce A. fabae defensive behavior, e.g. the frequency of kicking. L. fabarum attacks primed A. fabae to be more responsive to subsequent honeydew solicitation, such that experienced females improved their feeding success by alternating between the roles of parasitoid and ant mimic. These results reveal the possibility for mutualisms to evolve between L. fabarum and the ant species that tend A. fabae, since L. fabarum receive ant protection for their progeny and may benefit the ants by improving A. fabae responsiveness to honeydew solicitation. PMID:20879920

  6. Differential reactions of soybean isolines with combinations of aphid resistance genes Rag1, Rag2, and Rag3 to four soybean aphid biotypes

    USDA-ARS?s Scientific Manuscript database

    With the discovery of the soybean aphid (Aphis glycines Matsumura) as a devastating insect pest of soybean (Glycine max (L.) Merr.) in the United States, host resistance was recognized as an important management option. However, the identification of soybean aphid isolates exhibiting strong virulenc...

  7. Gene Expression Analysis of Parthenogenetic Embryonic Development of the Pea Aphid, Acyrthosiphon pisum, Suggests That Aphid Parthenogenesis Evolved from Meiotic Oogenesis

    PubMed Central

    Srinivasan, Dayalan G.; Abdelhady, Ahmed; Stern, David L.

    2014-01-01

    Aphids exhibit a form of phenotypic plasticity, called polyphenism, in which genetically identical females reproduce sexually during one part of the life cycle and asexually (via parthenogenesis) during the remainder of the life cycle. The molecular basis for aphid parthenogenesis is unknown. Cytological observations of aphid parthenogenesis suggest that asexual oogenesis evolved either through a modification of meiosis or from a mitotic process. As a test of these alternatives, we assessed the expression levels and expression patterns of canonical meiotic recombination and germline genes in the sexual and asexual ovaries of the pea aphid, Acyrthosiphon pisum. We observed expression of all meiosis genes in similar patterns in asexual and sexual ovaries, with the exception that some genes encoding Argonaute-family members were not expressed in sexual ovaries. In addition, we observed that asexual aphid tissues accumulated unspliced transcripts of Spo11, whereas sexual aphid tissues accumulated primarily spliced transcripts. In situ hybridization revealed Spo11 transcript in sexual germ cells and undetectable levels of Spo11 transcript in asexual germ cells. We also found that an obligately asexual strain of pea aphid produced little spliced Spo11 transcript. Together, these results suggest that parthenogenetic oogenesis evolved from a meiosis-like, and not a mitosis-like, process and that the aphid reproductive polyphenism may involve a modification of Spo11 gene activity. PMID:25501006

  8. Blackmargined aphid (Monellia caryella (Fitch); Hemiptera: Aphididae) honeydew production in pecan (Carya illinoinesis (Koch)) and implications for managing the pecan aphid complex in Texas

    USDA-ARS?s Scientific Manuscript database

    Field studies of the blackmargined aphid, Monellia caryella (Fitch), were conducted on three cultivars, “Cheyenne,” “Kiowa,” and “Pawnee,” of pecan, Carya illinoinisis (Wang) K. Koch. Aphid and natural enemy (lacewings, ladybird beetles, and spiders) densities were determined twice weekly by direct...

  9. Gene expression analysis of parthenogenetic embryonic development of the pea aphid, Acyrthosiphon pisum, suggests that aphid parthenogenesis evolved from meiotic oogenesis.

    PubMed

    Srinivasan, Dayalan G; Abdelhady, Ahmed; Stern, David L

    2014-01-01

    Aphids exhibit a form of phenotypic plasticity, called polyphenism, in which genetically identical females reproduce sexually during one part of the life cycle and asexually (via parthenogenesis) during the remainder of the life cycle. The molecular basis for aphid parthenogenesis is unknown. Cytological observations of aphid parthenogenesis suggest that asexual oogenesis evolved either through a modification of meiosis or from a mitotic process. As a test of these alternatives, we assessed the expression levels and expression patterns of canonical meiotic recombination and germline genes in the sexual and asexual ovaries of the pea aphid, Acyrthosiphon pisum. We observed expression of all meiosis genes in similar patterns in asexual and sexual ovaries, with the exception that some genes encoding Argonaute-family members were not expressed in sexual ovaries. In addition, we observed that asexual aphid tissues accumulated unspliced transcripts of Spo11, whereas sexual aphid tissues accumulated primarily spliced transcripts. In situ hybridization revealed Spo11 transcript in sexual germ cells and undetectable levels of Spo11 transcript in asexual germ cells. We also found that an obligately asexual strain of pea aphid produced little spliced Spo11 transcript. Together, these results suggest that parthenogenetic oogenesis evolved from a meiosis-like, and not a mitosis-like, process and that the aphid reproductive polyphenism may involve a modification of Spo11 gene activity.

  10. Residue behavior of combination formulations of insecticides in/on cabbage and their efficacy against aphids and diamondback moth.

    PubMed

    Gupta, Suman; Sharma, Rakesh K; Gajbhiye, Vijay T; Gupta, Ram K

    2015-01-01

    Persistence behavior of insecticides chlorpyriphos, profenofos, triazophos, cypermethrin, and deltamethrin following the use of three combination formulations Action 505 (chlorpyriphos + cypermethrin), Roket 44EC (profenofos + cypermethrin), and Anaconda Plus (triazophos + deltamethrin) was studied in cabbage following the spray application at the recommended and double doses. Bio-efficacy of these formulations was also evaluated against mustard aphids (Lipaphis erysimi Kaltenbach) and diamondback moth (Plutella xylostella L.). The residues of different insecticides persisted for 5-8 days at low dose and 8-12 days at high dose. The residues dissipated with time and 87-100% dissipation was recorded on the 8th day. The half-life values varied from 0.4 to 1.6 days. Based on the acceptable daily intake (ADI) values, a safe waiting period of 1 day has been suggested for the formulations Action 505 and Roket 44EC and 3 days for Anaconda Plus at the recommended dose of application. Action (1.6 L/ha) treatment was found to be the best as it significantly reduced the diamondback moth (DBM) (~60%) and aphid population (~70%) besides giving the highest yield (170% increase over control).

  11. DNA barcoding and the associated PhylAphidB@se website for the identification of European aphids (Insecta: Hemiptera: Aphididae).

    PubMed

    Coeur d'Acier, Armelle; Cruaud, Astrid; Artige, Emmanuelle; Genson, Gwenaëlle; Clamens, Anne-Laure; Pierre, Eric; Hudaverdian, Sylvie; Simon, Jean-Christophe; Jousselin, Emmanuelle; Rasplus, Jean-Yves

    2014-01-01

    Aphids constitute a diverse group of plant-feeding insects and are among the most important crop pests in temperate regions. Their morphological identification is time-consuming and requires specific knowledge, training and skills that may take years to acquire. We assessed the advantages and limits of DNA barcoding with the standard COI barcode fragment for the identification of European aphids. We constructed a large reference dataset of barcodes from 1020 specimens belonging to 274 species and 87 genera sampled throughout Europe and set up a database-driven website allowing species identification from query sequences. In this unbiased sampling of the taxonomic diversity of European aphids, intraspecific divergence ranged from 0.0% to 3.9%, with a mean value of 0.29%, whereas mean congeneric divergence was 6.4%, ranging from 0.0% to 15%. Neighbor-joining analysis generated a tree in which most species clustered in distinct genetic units. Most of the species with undifferentiated or overlapping barcodes belonged to the genus Aphis or, to a lesser extent, the genera Brachycaudus, Dysaphis and Macrosiphum. The taxa involved were always morphologically similar or closely related and belonged to species groups known to present taxonomic difficulties. These data confirm that COI barcoding is a useful identification tool for aphids. Barcode identification is straightforward and reliable for 80% of species, including some difficult to distinguish on the basis of morphological characters alone. Unsurprisingly, barcodes often failed to distinguish between species from groups for which classical taxonomy has also reached its limits, leading to endless revisions and discussions about species and subspecies definitions. In such cases, the development of an effective procedure for the accurate identification of aphid specimens continues to pose a difficult challenge.

  12. Role of the aphid species and their feeding locations in parasitization behavior of Aphelinus abdominalis, a parasitoid of the lettuce aphid Nasonovia ribisnigri.

    PubMed

    Shrestha, Govinda; Skovgård, Henrik; Reddy, Gadi V P; Steenberg, Tove; Enkegaard, Annie

    2017-01-01

    Aphid species feeding on lettuce occupy distinct feeding sites: the lettuce aphid Nasonovia ribisnigri prefers to feed on heart leaves, whereas the potato aphid Macrosiphum euphorbiae feeds only on outer leaves. The aphid parasitoid Aphelinus abdominalis, known to be able to regulate M. euphorbiae on many crops, has recently been indicated as a promising biocontrol candidate also for use against N. ribisnigri, a major pest of lettuce. This study therefore examined A. abdominalis parasitization preference between N. ribisnigri and M. euphorbiae and its ability to parasitize aphids feeding on different parts of lettuce plants. In addition, life history traits of A. abdominalis on these aphid species were investigated. In no-choice laboratory experiments on leaf discs and 24 h exposure, A. abdominalis successfully parasitized 54% and 60% of the offered N. ribisnigri and M. euphorbiae, respectively, with no significant difference. In the corresponding choice experiment, however, A. abdominalis had a tendency for a significantly higher preference for M. euphorbiae (38%) compared to N. ribisnigri (30%). Growth chamber experiments on whole plants demonstrated that A. abdominalis was able to parasitize aphids, regardless of their feeding locations on lettuce plants. However, aphid feeding behavior had a significant effect on the parasitization rate. A. abdominalis parasitized significantly higher percentages of M. euphorbiae or N. ribisnigri when aphids were exposed separately to parasitoids on whole lettuce plants as compared with N. ribisnigri exposed only on heart leaf. A significant preference of A. abdominalis for M. euphorbiae compared to N. ribisnigri was also observed in the growth chamber choice experiment. A high percentage of adult emergence (> 84%) and female-biased sex ratio (> 83%) were found irrespective of the aphid species.

  13. Role of the aphid species and their feeding locations in parasitization behavior of Aphelinus abdominalis, a parasitoid of the lettuce aphid Nasonovia ribisnigri

    PubMed Central

    Shrestha, Govinda; Skovgård, Henrik; Reddy, Gadi V. P.; Steenberg, Tove; Enkegaard, Annie

    2017-01-01

    Aphid species feeding on lettuce occupy distinct feeding sites: the lettuce aphid Nasonovia ribisnigri prefers to feed on heart leaves, whereas the potato aphid Macrosiphum euphorbiae feeds only on outer leaves. The aphid parasitoid Aphelinus abdominalis, known to be able to regulate M. euphorbiae on many crops, has recently been indicated as a promising biocontrol candidate also for use against N. ribisnigri, a major pest of lettuce. This study therefore examined A. abdominalis parasitization preference between N. ribisnigri and M. euphorbiae and its ability to parasitize aphids feeding on different parts of lettuce plants. In addition, life history traits of A. abdominalis on these aphid species were investigated. In no-choice laboratory experiments on leaf discs and 24 h exposure, A. abdominalis successfully parasitized 54% and 60% of the offered N. ribisnigri and M. euphorbiae, respectively, with no significant difference. In the corresponding choice experiment, however, A. abdominalis had a tendency for a significantly higher preference for M. euphorbiae (38%) compared to N. ribisnigri (30%). Growth chamber experiments on whole plants demonstrated that A. abdominalis was able to parasitize aphids, regardless of their feeding locations on lettuce plants. However, aphid feeding behavior had a significant effect on the parasitization rate. A. abdominalis parasitized significantly higher percentages of M. euphorbiae or N. ribisnigri when aphids were exposed separately to parasitoids on whole lettuce plants as compared with N. ribisnigri exposed only on heart leaf. A significant preference of A. abdominalis for M. euphorbiae compared to N. ribisnigri was also observed in the growth chamber choice experiment. A high percentage of adult emergence (> 84%) and female-biased sex ratio (> 83%) were found irrespective of the aphid species. PMID:28854232

  14. Changes in the Russian Wheat Aphid (Hemiptera: Aphididae) Biotype Complex in South Africa.

    PubMed

    Jankielsohn, Astrid

    2016-04-01

    Russian wheat aphid Diuraphis noxia (Kurdjumov) has spread from its native area in central Asia to all the major wheat-producing countries in the world to become an international wheat pest. Because the Russian wheat aphid is a serious threat to the wheat industry in South Africa, it is important to investigate the key factors involved in the distribution of Russian wheat aphid biotypes and in the changes of the Russian wheat aphid biotype complex in South Africa. There are currently four known Russian wheat aphid biotypes occurring in South Africa. Russian wheat aphid samples were collected from 2011 to 2014 during the wheat-growing season in spring and summer and these samples were screened to determine the biotype status. RWASA1 occurred predominantly in the Western Cape, while RWASA2 and RWASA3 occurred predominantly in the Eastern Free State. Following the first record of RWASA4 in 2011, this biotype was restricted to the Eastern Free State. The surveys suggest that the Russian wheat aphid bioype complex was more diverse in the Eastern Free State than in the other wheat production areas. There was also a shift in Russian wheat aphid biotype composition over time. The Russian wheat aphid biotype complex is dynamic, influenced by environmental factors such as host plants, altitude, and climate, and it can change and diversify over time causing fluctuation in populations over sites and years. This dynamic nature of the Russian wheat aphid will continue to challenge the development of Russian wheat aphid-resistant wheat cultivars in South Africa, and the continued monitoring of the biotypic and genetic structure, to determine genetic relatedness and variation in different biotypes, of Russian wheat aphid populations is important for protecting wheat.

  15. Comparative Life Histories of Greenbugs and Sugarcane Aphids (Hemiptera: Aphididae) Coinfesting Susceptible and Resistant Sorghums.

    PubMed

    Bayoumy, Mohamed H; Perumal, Ramaswamy; Michaud, J P

    2016-02-01

    Host-plant resistance has been a fundamental component of aphid management in cereal crops. Over decades, various sources of resistance to greenbug, Schizaphis graminum (Rondani), were bred into cultivars of sorghum, Sorghum bicolor (L.) Moench, to counter recurring virulent greenbug biotypes. The recent invasion of sugarcane aphid, Melanaphis sacchari (Zehntner), raised questions about plant-mediated interactions between the two aphids and the possibility of using greenbug antibiosis against sugarcane aphid. The present work was undertaken to characterize the impact of PI 550610 resistance to 'biotype I' greenbug, expressed in seed parental line KS 116B, on aphid life histories and to observe plant-mediated interactions between aphid species in its presence and absence. At 23°C, sugarcane aphid nymphs matured 1.5 d faster than greenbug nymphs on susceptible hybrid P8500, but at similar rates on the resistant line, which delayed maturity by 1-1.5 d in both species and increased juvenile mortality by three- to fourfold. Sugarcane aphid reproductive rate was double that of greenbug on susceptible sorghum (4.45 vs. 2.30 nymphs per female per day), but not significantly different on the resistant one (3.09 vs. 2.27). Thus, PI 550610 expresses antibiosis, not tolerance, to these aphids. Coinfestation of P8500 had a positive effect on greenbug intrinsic rate of increase (rm), which changed to negative on KS 116B, whereas the rm of sugarcane aphid was unaffected by coinfestation with greenbug on either cultivar. The results indicate that KS 116B will be useful for producing sugarcane aphid-resistant hybrids, and that PI 550610 antibiosis changes the sugarcane aphid-greenbug interspecific relationship from commensalism to amensalism.

  16. Potential Overwintering Locations of Soybean Aphid (Hemiptera: Aphididae) Colonizing Soybean in Ohio and Wisconsin.

    PubMed

    Crossley, Michael S; Hogg, David B

    2015-04-01

    Soybean aphids, Aphis glycines Matsumura, depend on long-distance, wind-aided dispersal to complete their life cycle. Despite our general understanding of soybean aphid biology, little is explicitly known about dispersal of soybean aphids between winter and summer hosts in North America. This study compared genotypic diversity of soybean aphids sampled from several overwintering locations in the Midwest and soybean fields in Ohio and Wisconsin to test the hypothesis that these overwintering locations are sources of the soybean colonists. In addition, air parcel trajectory analyses were used to demonstrate the potential for long-distance dispersal events to occur to or from these overwintering locations. Results suggest that soybean aphids from overwintering locations along the Illinois-Iowa border and northern Indiana-Ohio are potential colonists of soybean in Ohio and Wisconsin, but that Ohio is also colonized by soybean aphids from other unknown overwintering locations. Soybean aphids in Ohio and Wisconsin exhibit a small degree of population structure that is not associated with the locations of soybean fields in which they occur, but that may be related to specific overwintering environments, multiple introductions to North America, or spatial variation in aphid phenology. There may be a limited range of suitable habitat for soybean aphid overwintering, in which case management of soybean aphids may be more effective at their overwintering sites. Further research efforts should focus on discovering more overwintering locations of soybean aphid in North America, and the relative impact of short- and long-distance dispersal events on soybean aphid population dynamics.

  17. Impacts of thiamethoxam seed treatment and host plant resistance on the soybean aphid fungal pathogen, Pandora neoaphidis.

    PubMed

    Koch, Karrie A; Ragsdale, David W

    2011-12-01

    Since the introduction of soybean aphid, Aphis glycines Matsumura, from Asia, insecticide use in soybean has increased substantially in the north central United States. Insecticide seed treatments and aphid resistant soybean varieties are management tactics that may reduce reliance on foliar applications of broad-spectrum insecticides. Exploring potential nontarget impacts of these technologies will be an important step in incorporating them into aphid management programs. We investigated impacts of thiamethoxam seed treatment and Rag1 aphid resistant soybean on a fungal pathogen of soybean aphid, Pandora neoaphidis (Remaudière & Hennebert) Humber, via open plot and cage studies. We found that although thiamethoxam seed treatment did significantly lower aphid pressure in open plots compared with an untreated control, this reduction in aphid density translated into nonsignificant decreases in fungal disease prevalence in aphids. Furthermore, when aphid densities were approximately equal in seed treated and untreated soybean, no impact on aphid fungal disease was observed. In open plots, Rag1 resistant soybean experienced lower aphid pressure and aphid disease prevalence compared with a nonresistant isoline. However, in cages when aphid densities were equivalent in both resistant and susceptible soybean, resistance had no impact on aphid disease prevalence. The addition of thiamethoxam seed treatment to resistant soybean yielded aphid densities and aphid disease prevalence similar to untreated, resistant soybean. These studies provide evidence that thiamethoxam seed treatments and Rag1 resistance can impact P. neoaphidis via decreased aphid densities; however, this impact is minimal, implying use of seed treatments and host plant resistance are compatible with P. neoaphidis.

  18. Aphid Infestation Increases Fusarium langsethiae and T-2 and HT-2 Mycotoxins in Wheat

    PubMed Central

    Drakulic, Jassy; Ajigboye, Olubukola; Swarup, Ranjan; Bruce, Toby

    2016-01-01

    ABSTRACT Fusarium langsethiae is a fungal pathogen of cereal crops that is an increasing problem in northern Europe, but much of its epidemiology is poorly understood. The species produces the mycotoxins T-2 and HT-2, which are highly toxic. It was hypothesized that grain aphids, Sitobion avenae, may transmit F. langsethiae inoculum between wheat plants, and a series of transmission experiments and volatile chemical analyses was performed to test this. Manual translocation of aphids from inoculated to uninfected hosts resulted in pathogen DNA accumulation in hosts. However, the free movement of wingless aphids from infected to healthy plants did not. The addition of winged aphids reared on F. langsethiae-inoculated wheat seedlings to wheat plants also did not achieve successful pathogen transfer. While our data suggested that aphid transmission of the pathogen was not very efficient, we observed an increase in disease when aphids were present. After seedling inoculation, an increase in pathogen DNA accumulation in seedling leaves was observed upon treatment with aphids. Furthermore, the presence of aphids on wheat plants with F. langsethiae-inoculated ears not only led to a rise in the amount of F. langsethiae DNA in infected grain but also to an increase in the concentrations of T-2 and HT-2 toxins, with more than 3-fold higher toxin levels than diseased plants without aphids. This work highlights that aphids increase the susceptibility of wheat host plants to F. langsethiae and that aphid infestation is a risk factor for accumulating increased levels of T-2 and HT-2 in wheat products. IMPORTANCE Fusarium langsethiae is shown here to cause increased contamination levels of grain with toxins produced by fungus when aphids share the host plant. This effect has also recently been demonstrated with Fusarium graminearum, yet the two fungal species show stark differences in their effect on aphid populations. In both cases, aphids improve the ability of the pathogens to

  19. Modification of non-vector aphid feeding behavior on virus-infected host plant.

    PubMed

    Hu, Zuqing; Zhao, Huiyan; Thieme, Thomas

    2013-01-01

    Virus-infected host plants can have positive, neutral or negative effects on vector aphids. Even though the proportion of non-vector aphids associated with a plant far exceeds that of vector species, little is known about the effect of virus-infected plants on non-vector aphids. In the present study, the English grain aphid Sitobion avenae (Fabricius) (Hemiptera: Aphididae), a non-vector of Wheat dwarf virus (WDV) and Cereal yellow dwarf virus-RPV (CYDV-RPV), was monitored on, virus-infected, virus-free and leafhopper/aphid-infested, and virus- and insect-free (control) barley, Hordeum vulgare L. (Poales: Poaceae), plants. Electrical penetration graph recordings were performed. Compared with the control plants, S. avenae on infected plants exhibited reduced non-probing and pathway phase, and increased phloem sap ingestion phase, and more aphids reached sustained phloem ingestion. However, the electrical penetration graph parameters described above showed no significant differences in aphid feeding behavior on virus-free and vector pre-infested plants and the control barley plants during S. avenae feeding. The results suggest that WDV/CYDV-RPV-infected host plants positively affected the feeding behavior of the non-vector aphid S. avenae. Based on these results, the reasons and trends among the virus-infected host plants' effects on the feeding behavior of non-vector aphids are discussed.

  20. A dietary test of putative deleterious sterols for the aphid Myzus persicae.

    PubMed

    Bouvaine, Sophie; Faure, Marie-Line; Grebenok, Robert J; Behmer, Spencer T; Douglas, Angela E

    2014-01-01

    The aphid Myzus persicae displays high mortality on tobacco plants bearing a transgene which results in the accumulation of the ketosteroids cholestan-3-one and cholest-4-en-3-one in the phloem sap. To test whether the ketosteroids are the basis of the plant resistance to the aphids, M. persicae were reared on chemically-defined diets with different steroid contents at 0.1-10 µg ml(-1). Relative to sterol-free diet and dietary supplements of the two ketosteroids and two phytosterols, dietary cholesterol significantly extended aphid lifespan and increased fecundity at one or more dietary concentrations tested. Median lifespan was 50% lower on the diet supplemented with cholest-4-en-3-one than on the cholesterol-supplemented diet. Aphid feeding rate did not vary significantly across the treatments, indicative of no anti-feedant effect of any sterol/steroid. Aphids reared on diets containing equal amounts of cholesterol and cholest-4-en-3-one showed fecundity equivalent to aphids on diets containing only cholesterol. Aphids were reared on diets that reproduced the relative steroid abundance in the phloem sap of the control and modified tobacco plants, and their performance on the two diet formulations was broadly equivalent. We conclude that, at the concentrations tested, plant ketosteroids support weaker aphid performance than cholesterol, but do not cause acute toxicity to the aphids. In plants, the ketosteroids may act synergistically with plant factors absent from artificial diets but are unlikely to be solely responsible for resistance of modified tobacco plants.

  1. New data on aphid fauna (Hemiptera, Aphididae) in Algeria

    PubMed Central

    Laamari, Malik; d’Acier, Armelle Coeur; Jousselin, Emmanuelle

    2013-01-01

    Abstract A survey of aphids was carried out during the period 2008-2011 in different regions of Algeria by collecting and identifying aphids and their host plants. Aphids were collected from 46 host plants. Forty-six species were reported including thirty-six species which were recorded for the first time in this country and thirty species which were recorded for the first time in the Maghreb (North Africa). This study extends the number of known Algerian aphid to 156 species. PMID:24039520

  2. Ethylene contributes to potato aphid susceptibility in a compatible tomato host.

    PubMed

    Mantelin, Sophie; Bhattarai, Kishor K; Kaloshian, Isgouhi

    2009-01-01

    Resistance to potato aphid (Macrosiphum euphorbiae) in tomato (Solanum lycopersicum) is conferred by Mi-1. Early during both compatible and incompatible interactions, potato aphid feeding induces the expression of ethylene (ET) biosynthetic genes. Here, we used genetic and pharmacologic approaches to investigate the role of ET signaling in basal defense and Mi-1-mediated resistance to potato aphid in tomato. The effect of potato aphid infestation on ET biosynthesis in susceptible and resistant plants was assessed. Aphid bioassays were performed using plants impaired in ET biosynthesis or perception using virus-induced gene silencing, the Never ripe (Nr) mutant, and 1-methylcyclopropene (MCP) treatment. A burst of ET was observed after aphid feeding in both resistant and susceptible plants, correlated with an increase in the expression of ET biosynthetic genes. However, impairing ET signaling or biosynthesis did not compromise Mi-1-mediated resistance but it did decrease susceptibility to potato aphid in a compatible host. ET may not play a significant role in Mi-1-mediated resistance to potato aphids in tomato but modulates the host basal defense, enhancing its susceptibility to the aphid.

  3. Proteomic Investigation of Aphid Honeydew Reveals an Unexpected Diversity of Proteins

    PubMed Central

    Haubruge, Eric; Hance, Thierry; Thonart, Philippe; De Pauw, Edwin; Francis, Frédéric

    2013-01-01

    Aphids feed on the phloem sap of plants, and are the most common honeydew-producing insects. While aphid honeydew is primarily considered to comprise sugars and amino acids, its protein diversity has yet to be documented. Here, we report on the investigation of the honeydew proteome from the pea aphid Acyrthosiphon pisum. Using a two-Dimensional Differential in-Gel Electrophoresis (2D-Dige) approach, more than 140 spots were isolated, demonstrating that aphid honeydew also represents a diverse source of proteins. About 66% of the isolated spots were identified through mass spectrometry analysis, revealing that the protein diversity of aphid honeydew originates from several organisms (i.e. the host aphid and its microbiota, including endosymbiotic bacteria and gut flora). Interestingly, our experiments also allowed to identify some proteins like chaperonin, GroEL and Dnak chaperones, elongation factor Tu (EF-Tu), and flagellin that might act as mediators in the plant-aphid interaction. In addition to providing the first aphid honeydew proteome analysis, we propose to reconsider the importance of this substance, mainly acknowledged to be a waste product, from the aphid ecology perspective. PMID:24086359

  4. Ecological effects of aphid abundance, genotypic variation, and contemporary evolution on plants.

    PubMed

    Turley, Nash E; Johnson, Marc T J

    2015-07-01

    Genetic variation and contemporary evolution within populations can shape the strength and nature of species interactions, but the relative importance of these forces compared to other ecological factors is unclear. We conducted a field experiment testing the effects of genotypic variation, abundance, and presence/absence of green peach aphids (Myzus persicae) on the growth, leaf nitrogen, and carbon of two plant species (Brassica napus and Solanum nigrum). Aphid genotype affected B. napus but not S. nigrum biomass explaining 20 and 7% of the total variation, respectively. Averaging across both plant species, the presence/absence of aphids had a 1.6× larger effect size (Cohen's d) than aphid genotype, and aphid abundance had the strongest negative effects on plant biomass explaining 29% of the total variation. On B. napus, aphid genotypes had different effects on leaf nitrogen depending on their abundance. Aphids did not influence leaf nitrogen in S. nigrum nor leaf carbon in either species. We conducted a second experiment in the field to test whether contemporary evolution could affect plant performance. Aphid populations evolved in as little as five generations, but the rate and direction of this evolution did not consistently vary between plant species. On one host species (B. napus), faster evolving populations had greater negative effects on host plant biomass, with aphid evolutionary rate explaining 23% of the variation in host plant biomass. Together, these results show that genetic variation and evolution in an insect herbivore can play important roles in shaping host plant ecology.

  5. Aphid secondary symbionts do not affect prey attractiveness to two species of predatory lady beetles

    PubMed Central

    Wolf, Candice; Voisin, Dené; Wolf, Seth

    2017-01-01

    Heritable symbionts have been found to mediate interactions between host species and their natural enemies in a variety of organisms. Aphids, their facultative symbionts, and their potential fitness effects have been particularly well-studied. For example, the aphid facultative symbiont Regiella can protect its host from infection from a fungal pathogen, and aphids with Hamiltonella are less likely to be parasitized by parasitic wasps. Recent work has also found there to be negative fitness effects for the larvae of two species of aphidophagous lady beetles that consumed aphids with facultative symbionts. In both species, larvae that consumed aphids with secondary symbionts were significantly less likely to survive to adulthood. In this study we tested whether adult Harmonia axyridis and Hippodamia convergens lady beetles avoided aphids with symbionts in a series of choice experiments. Adults of both lady beetle species were as likely to choose aphids with symbionts as those without, despite the potential negative fitness effects associated with consuming aphids with facultative symbionts. This may suggest that under natural conditions aphid secondary symbionts are not a significant source of selection for predatory lady beetles. PMID:28880922

  6. Heterodera schachtii nematodes interfere with aphid-plant relations on Brassica oleracea.

    PubMed

    Hol, W H Gera; De Boer, Wietse; Termorshuizen, Aad J; Meyer, Katrin M; Schneider, Johannes H M; Van Der Putten, Wim H; Van Dam, Nicole M

    2013-09-01

    Aboveground and belowground herbivore species modify plant defense responses differently. Simultaneous attack can lead to non-additive effects on primary and secondary metabolite composition in roots and shoots. We previously found that aphid (Brevicoryne brassicae) population growth on Brassica oleracea was reduced on plants that were infested with nematodes (Heterodera schachtii) prior (4 weeks) to aphid infestation. Here, we examined how infection with root-feeding nematodes affected primary and secondary metabolites in the host plant and whether this could explain the increase in aphid doubling time from 3.8 to 6.7 days. We hypothesized that the effects of herbivores on plant metabolites would depend on the presence of the other herbivore and that nematode-induced changes in primary metabolites would correlate with reduced aphid performance. Total glucosinolate concentration in the leaves was not affected by nematode presence, but the composition of glucosinolates shifted, as gluconapin concentrations were reduced, while gluconapoleiferin concentrations increased in plants exposed to nematodes. Aphid presence increased 4-methoxyglucobrassicin concentrations in leaves, which correlated positively with the number of aphids per plant. Nematodes decreased amino acid and sugar concentrations in the phloem. Aphid population doubling time correlated negatively with amino acids and glucosinolate levels in leaves, whereas these correlations were non-significant when nematodes were present. In conclusion, the effects of an herbivore on plant metabolites were independent of the presence of another herbivore. Nematode presence reduced aphid population growth and disturbed feeding relations between plants and aphids.

  7. A Secreted MIF Cytokine Enables Aphid Feeding and Represses Plant Immune Responses.

    PubMed

    Naessens, Elodie; Dubreuil, Géraldine; Giordanengo, Philippe; Baron, Olga Lucia; Minet-Kebdani, Naïma; Keller, Harald; Coustau, Christine

    2015-07-20

    Aphids attack virtually all plant species and cause serious crop damages in agriculture. Despite their dramatic impact on food production, little is known about the molecular processes that allow aphids to exploit their host plants. To date, few aphid salivary proteins have been identified that are essential for aphid feeding, and their nature and function remain largely unknown. Here, we show that a macrophage migration inhibitory factor (MIF) is secreted in aphid saliva. In vertebrates, MIFs are important pro-inflammatory cytokines regulating immune responses. MIF proteins are also secreted by parasites of vertebrates, including nematodes, ticks, and protozoa, and participate in the modulation of host immune responses. The finding that a plant parasite secretes a MIF protein prompted us to question the role of the cytokine in the plant-aphid interaction. We show here that expression of MIF genes is crucial for aphid survival, fecundity, and feeding on a host plant. The ectopic expression of aphid MIFs in leaf tissues inhibits major plant immune responses, such as the expression of defense-related genes, callose deposition, and hypersensitive cell death. Functional complementation analyses in vivo allowed demonstrating that MIF1 is the member of the MIF protein family that allows aphids to exploit their host plants. To our knowledge, this is the first report of a cytokine that is secreted by a parasite to modulate plant immune responses. Our findings suggest a so-far unsuspected conservation of infection strategies among parasites of animal and plant species.

  8. Peroxiredoxin 1 protects the pea aphid Acyrthosiphon pisum from oxidative stress induced by Micrococcus luteus infection.

    PubMed

    Zhang, Yongdong; Lu, Zhiqiang

    2015-05-01

    Reactive oxygen species (ROSs) are generated in organisms in response to infections caused by invading microbes. However, excessive ROSs will inflict oxidative damage on the host. Peroxiredoxins (Prxs) are antioxidative enzymes that may eliminate ROSs efficiently. In this study, ApPrx1 from the pea aphid Acyrthosiphon pisum was cloned, and its function was investigated in vitro and in vivo. In the presence of DTT, recombinant ApPrx1 protein from Escherichia coli showed antioxidative activity by eliminating H2O2 effectively. The H2O2 levels were significantly higher in Micrococcus luteus-infected aphids than in uninfected aphids, and ApPrx1 expression was remarkably up-regulated when the aphids were infected with M. luteus or injected with H2O2. When ApPrx1 expression was reduced by dsRNA injection, the survival of the aphids decreased significantly after M. luteus infection. Knockdown of ApPrx1 decreased M. luteus loads inside the aphids 48h post-infection. While under infection conditions, the H2O2 levels were much higher in ApPrx1 knockdown aphids than in dsGFP-injected aphids, indicating that the decreased survival of the aphids was caused by increased oxidative stress. Taken together, our results reveal that ApPrx1 plays a protective role in oxidative stress caused by bacterial infection. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Anticipatory and reactive crouching of pea aphids in response to environmental perturbations.

    PubMed

    Ben-Ari, Matan; Talal, Stav; Inbar, Moshe

    2014-10-01

    Animals use different strategies to deal with changing environmental conditions. While standing and feeding on their host plant, aphids (Hemiptera: Aphididae) may be exposed to detrimental environmental perturbations, such as strong winds. If aphids are forcibly blown off the plant and spend time on the ground, they will face additional dangers by both ground-dwelling predators and detrimental soil temperature. It is therefore adaptive for aphids to behave in a way that lowers the risk of being removed from the plant. We observed that pea aphids (Acyrthosiphon pisum (Harris)) display a specific crouched body posture, previously undescribed, which reduces their chance of being carried off from the plant by sudden winds. We exposed aphids in the laboratory to different cues indicative of a windy environment: wind, plant vibration, and visual stimuli. We found that aphids crouch in two situations: 1) reactively, when they are being pulled by a continuous gust of wind threatening to dislodge them. 2) Anticipatorily, when environmental cues, such as plant vibration or continuous movement near their host plant, may signify that sudden wind gusts are expected. Crouching aphids were less likely to be dislodged by a sudden air stream or plant vibration than were aphids that did not crouch. Crouching thus improves the aphids' chances of remaining on their host plant under unfavorable environmental conditions.

  10. Bacteria may contribute to distant species recognition in ant-aphid mutualistic relationships.

    PubMed

    Fischer, Christophe Y; Detrain, Claire; Thonart, Philippe; Haubruge, Eric; Francis, Frédéric; Verheggen, François J; Lognay, Georges C

    2017-04-01

    Mutualistic interactions between ant and aphid species have been the subject of considerable historical and contemporary investigations, the primary benefits being cleaning and protection for the aphids and carbohydrate-rich honeydew for the ants. Questions remained, however, as to the volatile semiochemical factor influencing this relationship. A recent study highlighted the role of bacterial honeydew volatile compounds in ant attraction. Here, ant's ability to distantly discriminate 2 aphid species was investigated based on bacterial honeydew semiochemicals emissions using a two-way olfactometer. Both the mutualistic aphid Aphis fabae L. and the nonmyrmecophilous aphid Acyrthosiphon pisum Harris were found to be attractive for the ant Lasius niger L. The level of attraction was similar in both assays (control vs. one of the aphid species). However, when given a choice between these 2 aphid species, ants showed a significant preference for Aphis fabae. Honeydew volatiles, mostly from bacterial origins, are known to be a key element in ant attraction. Using the same olfactometry protocol, the relative attractiveness of volatiles emitted by honeydews collected from each aphid species and by bacteria isolated from each honeydew was investigated. Again, ants significantly preferred volatiles released by Aphis fabae honeydew and bacteria. This information suggests that microbial honeydew volatiles enable ants to distantly discriminate aphid species. These results strengthen the interest of studying the occurrence and potential impact of microorganisms in insect symbioses. © 2015 Institute of Zoology, Chinese Academy of Sciences.

  11. Identification of Conditions for Successful Aphid Control by Ladybirds in Greenhouses

    PubMed Central

    Riddick, Eric W.

    2017-01-01

    As part of my research on the mass production and augmentative release of ladybirds, I reviewed the primary research literature to test the prediction that ladybirds are effective aphid predators in greenhouses. Aphid population reduction exceeded 50% in most studies and ladybird release rates usually did not correlate with aphid reduction. The ratio of aphid reduction/release rate was slightly less for larvae than adults in some studies, suggesting that larvae were less effective (than adults) in suppressing aphids. Some adult releases were inside cages, thereby limiting adult dispersion from plants. Overall, the ratio of aphid reduction/release rate was greatest for ladybird adults of the normal strain (several species combined), but least for adults of a flightless Harmonia axyridis strain. The combined action of ladybirds and hymenopteran parasitoids could have a net positive effect on aphid population suppression and, consequently, on host (crop) plants. However, ladybird encounters with aphid-tending or foraging ants must be reduced. Deploying ladybirds to help manage aphids in greenhouses and similar protective structures is encouraged. PMID:28350349

  12. Plant chemical defense indirectly mediates aphid performance via interactions with tending ants.

    PubMed

    Züst, Tobias; Agrawal, Anurag A

    2017-03-01

    The benefits of mutualistic interactions are often highly context dependent. We studied the interaction between the milkweed aphid Aphis asclepiadis and a tending ant, Formica podzolica. Although this interaction is generally considered beneficial, variation in plant genotype may alter it from mutualistic to antagonistic. Here we link the shift in strength and relative benefit of the ant-aphid interaction to plant genotypic variation in the production of cardenolides, a class of toxic defensive chemicals. In a field experiment with highly variable genotypes of the common milkweed (Asclepias syriaca), we show that plant cardenolides, especially polar forms, are ingested by aphids and excreted in honeydew proportionally to plant concentrations without directly affecting aphid performance. Ants consume honeydew, and aphids that excreted high amounts of cardenolides received fewer ant visits, which in turn reduced aphid survival. On at least some plant genotypes, aphid numbers per plant were reduced in the presence of ants to levels lower than in corresponding ant-exclusion treatments, suggesting antagonistic ant behavior. Although cardenolides appear ineffective as direct plant defenses against aphids, the multi-trophic context reveals an ant-mediated negative indirect effect on aphid performance and population dynamics. © 2016 by the Ecological Society of America.

  13. Modification of Non-Vector Aphid Feeding Behavior on Virus-Infected Host Plant

    PubMed Central

    Hu, Zuqing; Zhao, Huiyan; Thieme, Thomas

    2013-01-01

    Virus-infected host plants can have positive, neutral or negative effects on vector aphids. Even though the proportion of non-vector aphids associated with a plant far exceeds that of vector species, little is known about the effect of virus-infected plants on non-vector aphids. In the present study, the English grain aphid Sitobion avenae (Fabricius) (Hemiptera: Aphididae), a non-vector of Wheat dwarf virus (WDV) and Cereal yellow dwarf virus-RPV (CYDV-RPV), was monitored on, virus-infected, virus-free and leafhopper/aphid-infested, and virus- and insect-free (control) barley, Hordeum vulgare L. (Poales: Poaceae), plants. Electrical penetration graph recordings were performed. Compared with the control plants, S. avenae on infected plants exhibited reduced non-probing and pathway phase, and increased phloem sap ingestion phase, and more aphids reached sustained phloem ingestion. However, the electrical penetration graph parameters described above showed no significant differences in aphid feeding behavior on virus-free and vector pre-infested plants and the control barley plants during S. avenae feeding. The results suggest that WDV/CYDV-RPV-infected host plants positively affected the feeding behavior of the non-vector aphid S. avenae. Based on these results, the reasons and trends among the virus-infected host plants' effects on the feeding behavior of non-vector aphids are discussed. PMID:23902296

  14. NDVI to Detect Sugarcane Aphid Injury to Grain Sorghum.

    PubMed

    Elliott, N C; Backoulou, G F; Brewer, M J; Giles, K L

    2015-06-01

    Multispectral remote sensing has potential to provide quick and inexpensive information on sugarcane aphid, Melanaphis sacchari (Zehntner), pest status in sorghum fields. We describe a study conducted to determine if injury caused by sugarcane aphid to sorghum plants in fields of grain sorghum could be detected using multispectral remote sensing from a fixed wing aircraft. A study was conducted in commercial grain sorghum fields in the Texas Gulf Coast region in June 2014. Twenty-six commercial grain sorghum fields were selected and rated for the level of injury to sorghum plants in the field caused by sugarcane aphid. Plant growth stage ranged from 5.0 (watery ripe) to 7.0 (hard dough) among fields; and plant injury rating from sugarcane aphid ranged from 1.0 (little or no injury) to 4.0 (>40% of plants displaying injury) among fields. The normalized differenced vegetation index (NDVI) is calculated from light reflectance in the red and near-infrared wavelength bands in multispectral imagery and is a common index of plant stress. High NDVI indicates low levels of stress and low NDVI indicates high stress. NDVI ranged from -0.07 to 0.26 among fields. The correlation between NDVI and plant injury rating was negative and significant, as was the correlation between NDVI and plant growth stage. The negative correlation of NDVI with injury rating indicated that plant stress increased with increasing plant injury. Reduced NDVI with increasing plant growth probably resulted from reduced photosynthetic activity in more mature plants. The correlation between plant injury rating and plant growth stage was positive and significant indicating that plant injury from sugarcane aphid increased as plants matured. The partial correlation of NDVI with plant injury rating was negative and significant indicating that NDVI decreased with increasing plant injury after adjusting for its association with plant growth stage. We demonstrated that remotely sensed imagery acquired from grain

  15. Coexistence of three specialist aphids on common milkweed, Asclepias syriaca.

    PubMed

    Smith, R A; Mooney, K A; Agrawal, A A

    2008-08-01

    Coexistence of host-specific herbivores on plants is believed to be governed by interspecific interactions, but few empirical studies have systematically unraveled these dynamics. We investigated the role of several factors in promoting coexistence among the aphids Aphis nerii, Aphis asclepiadis, and Myzocallis asclepiadis that all specialize on common milkweed (Asclepias syriaca). Competitive exclusion is thought to occur when interspecific competition is stronger than intraspecific competition. Consequently, we investigated whether predators, mutualists, or resource quality affected the strength of intra- vs. interspecific competition among aphids in factorial manipulations of competition with exposure to predation, ants, and variable plant genotypes in three separate experiments. In the predation x competition experiment, predators reduced aphid per capita growth by 66%, but the strength of intra- and interspecific competition did not depend on predators. In the ants x competition experiment, ants reduced per capita growth of A. nerii and M. asclepiadis (neither of which were mutualists with ants) by approximately one-half. In so doing, ants ameliorated the negative effects of these competitors on ant-tended A. asclepiadis by two-thirds, representing a novel benefit of ant-aphid mutualism. Nevertheless, ants alone did not explain the persistence of competitively inferior A. asclepiadis as, even in the presence of ants, interspecific competition remained stronger than intraspecific competition. In the plant genotype x competition experiment, both A. asclepiadis and M. asclepiadis were competitively inferior to A. nerii, with the strength of interspecific competition exceeding that of intraspecific competition by 83% and 23%, respectively. Yet these effects differed among milkweed genotypes, and there were one or more plant genotypes for each aphid species where coexistence was predicted. A synthesis of our results shows that predators play little or no role in

  16. Aphid infestation affecting the biogeochemistry of European beech saplings

    NASA Astrophysics Data System (ADS)

    Michalzik, B.; Levia, D. F., Jr.; Bischoff, S.; Näthe, K.

    2014-12-01

    Mass outbreaks of herbivore insects are known to perturb the functional properties of forests. However, it is less clear how endemic to moderate aboveground herbivory affects the vertical flow of nutrients from tree canopies to the soil. Here, we report on the effects of low to moderate infestation levels of the woolly beech aphid (Phyllaphis fagi L.) on the nutrient dynamics and hydrology of European beech (Fagus sylvatica L.). In a potted sapling experiment, we followed the vertical dynamics of nutrients via throughfall (TF), stemflow (SF) and litter leachates (LL) collected over ten weeks underneath infested and uninfested control trees. Aphid infestation amplifies the fluxes of K+, Mn2+ and particulate nitrogen (0.45μm < PN < 500 μm) in TF solution by 42% for K+, 59% for Mn2+ and 13% for PN relative to the control. In contrast, fluxes of NH4-N and SO4-S diminished during peaking aphid abundance by 26 and 16%, respectively. Differences in canopy-derived dissolved nitrogen and carbon compounds, sulfur (S), Ca2+, Mg2+, Na+ were < 10%. The effect of aphid abundance on nutrient dynamics was most notable in TF and SF and diminished in LL.Aphid infestation greatly altered the SF fluxes of DOC, K+, Mn2+, DON and sulfur-species, which were significantly concentrated at the tree base by "funneling" the rainfall through the canopy biomass to the trunk. Normalized to one square meter, water and nutrient fluxes were amplified by a factor of up to 200 compared to TF.Imaging of leaf surfaces by scanning electron microscopy exhibited notable differences of the surface morphology and microbiology of control, lightly infested, and heavily infested leaves. This observation might point to an aphid-mediated alteration of the phyllosphere ecology triggering the microbial uptake of NH4-N and SO4-S and its transformation to particulate N by magnified biomass growth of the phyllosphere microflora, consequently changing the chemical partitioning and temporal availability of nitrogen.

  17. Evidence of indirect symbiont conferred protection against the predatory lady beetle Harmonia axyridis in the pea aphid.

    PubMed

    Kovacs, Jennifer L; Wolf, Candice; Voisin, Dené; Wolf, Seth

    2017-07-11

    Defensive symbionts can provide significant fitness advantages to their hosts. Facultative symbionts can protect several species of aphid from fungal pathogens, heat shock, and parasitism by parasitoid wasps. Previous work found that two of these facultative symbionts can also indirectly protect pea aphids from predation by the lady beetle Hippocampus convergens. When aphids reproduce asexually, there is extremely high relatedness among aphid clone-mates and often very limited dispersal. Under these conditions, symbionts may indirectly protect aphid clone-mates from predation by negatively affecting the survival of a predator after the consumption of aphids harboring the same vertically transmitted facultative symbionts. In this study, we wanted to determine whether this indirect protection extended to another lady beetle species, Harmonia axyridis. We fed Ha. axyridis larvae aphids from one of four aphid sub-clonal symbiont lines which all originated from the same naturally symbiont free clonal aphid lineage. Three of the sub-clonal lines harbor different facultative symbionts that were introduced to the lines via microinjection. Therefore these sub-clonal lineages vary primarily in their symbiont composition, not their genetic background. We found that aphid facultative symbionts affected larval survival as well as pupal survival in their predator Ha. axyridis. Additionally, Ha. axyridis larvae fed aphids with the Regiella symbiont had significantly longer larval developmental times than beetle larvae fed other aphids, and females fed aphids with the Regiella symbiont as larvae weighed less as adults. These fitness effects were different from those previously found in another aphid predator Hi. convergens suggesting that the fitness effects may not be the same in different aphid predators. Overall, our findings suggest that some aphid symbionts may indirectly benefit their clonal aphid hosts by negatively impacting the development and survival of a lady beetle

  18. Masculinization of the X Chromosome in the Pea Aphid

    PubMed Central

    Jaquiéry, Julie; Rispe, Claude; Roze, Denis; Legeai, Fabrice; Le Trionnaire, Gaël; Stoeckel, Solenn; Mieuzet, Lucie; Da Silva, Corinne; Poulain, Julie; Prunier-Leterme, Nathalie; Ségurens, Béatrice; Tagu, Denis; Simon, Jean-Christophe

    2013-01-01

    Evolutionary theory predicts that sexually antagonistic mutations accumulate differentially on the X chromosome and autosomes in species with an XY sex-determination system, with effects (masculinization or feminization of the X) depending on the dominance of mutations. Organisms with alternative modes of inheritance of sex chromosomes offer interesting opportunities for studying sexual conflicts and their resolution, because expectations for the preferred genomic location of sexually antagonistic alleles may differ from standard systems. Aphids display an XX/X0 system and combine an unusual inheritance of the X chromosome with the alternation of sexual and asexual reproduction. In this study, we first investigated theoretically the accumulation of sexually antagonistic mutations on the aphid X chromosome. Our results show that i) the X is always more favourable to the spread of male-beneficial alleles than autosomes, and should thus be enriched in sexually antagonistic alleles beneficial for males, ii) sexually antagonistic mutations beneficial for asexual females accumulate preferentially on autosomes, iii) in contrast to predictions for standard systems, these qualitative results are not affected by the dominance of mutations. Under the assumption that sex-biased gene expression evolves to solve conflicts raised by the spread of sexually antagonistic alleles, one expects that male-biased genes should be enriched on the X while asexual female-biased genes should be enriched on autosomes. Using gene expression data (RNA-Seq) in males, sexual females and asexual females of the pea aphid, we confirm these theoretical predictions. Although other mechanisms than the resolution of sexual antagonism may lead to sex-biased gene expression, we argue that they could hardly explain the observed difference between X and autosomes. On top of reporting a strong masculinization of the aphid X chromosome, our study highlights the relevance of organisms displaying an alternative

  19. Alfalfa Leaf Curl Virus: an Aphid-Transmitted Geminivirus.

    PubMed

    Roumagnac, Philippe; Granier, Martine; Bernardo, Pauline; Deshoux, Maëlle; Ferdinand, Romain; Galzi, Serge; Fernandez, Emmanuel; Julian, Charlotte; Abt, Isabelle; Filloux, Denis; Mesléard, François; Varsani, Arvind; Blanc, Stéphane; Martin, Darren P; Peterschmitt, Michel

    2015-09-01

    The family Geminiviridae comprises seven genera differentiated by genome organization, sequence similarity, and insect vector. Capulavirus, an eighth genus, has been proposed to accommodate two newly discovered highly divergent geminiviruses that presently have no known vector. Alfalfa leaf curl virus, identified here as a third capulavirus, is shown to be transmitted by Aphis craccivora. This is the first report of an aphid-transmitted geminivirus.

  20. Alfalfa Leaf Curl Virus: an Aphid-Transmitted Geminivirus

    PubMed Central

    Roumagnac, Philippe; Granier, Martine; Bernardo, Pauline; Deshoux, Maëlle; Ferdinand, Romain; Galzi, Serge; Fernandez, Emmanuel; Julian, Charlotte; Abt, Isabelle; Filloux, Denis; Mesléard, François; Varsani, Arvind; Blanc, Stéphane; Martin, Darren P.

    2015-01-01

    The family Geminiviridae comprises seven genera differentiated by genome organization, sequence similarity, and insect vector. Capulavirus, an eighth genus, has been proposed to accommodate two newly discovered highly divergent geminiviruses that presently have no known vector. Alfalfa leaf curl virus, identified here as a third capulavirus, is shown to be transmitted by Aphis craccivora. This is the first report of an aphid-transmitted geminivirus. PMID:26109720

  1. The Potato Aphid Salivary Effector Me47 Is a Glutathione-S-Transferase Involved in Modifying Plant Responses to Aphid Infestation

    PubMed Central

    Kettles, Graeme J.; Kaloshian, Isgouhi

    2016-01-01

    Polyphagous aphid pests cause considerable economic damage to crop plants, primarily through the depletion of photoassimilates and transfer of viruses. The potato aphid (Macrosiphum euphorbiae) is a notable pest of solanaceous crops, however, the molecular mechanisms that underpin the ability to colonize these hosts are unknown. It has recently been demonstrated that like other aphid species, M. euphorbiae injects a battery of salivary proteins into host plants during feeding. It is speculated that these proteins function in a manner analagous to secreted effectors from phytopathogenic bacteria, fungi and oomycetes. Here, we describe a novel aphid effector (Me47) which was identified from the potato aphid salivary secretome as a putative glutathione-S-transferase (GST). Expression of Me47 in Nicotiana benthamiana enhanced reproductive performance of green peach aphid (Myzus persicae). Similarly, delivery of Me47 into leaves of tomato (Solanum lycopersicum) by Pseudomonas spp. enhanced potato aphid fecundity. In contrast, delivery of Me47 into Arabidopsis thaliana reduced GPA reproductive performance, indicating that Me47 impacts the outcome of plant–aphid interactions differently depending on the host species. Delivery of Me47 by the non-pathogenic Pseudomonas fluorescens revealed that Me47 protein or activity triggers defense gene transcriptional upregulation in tomato but not Arabidopsis. Recombinant Me47 was purified and demonstrated to have GST activity against two specific isothiocyanates (ITCs), compounds implicated in herbivore defense. Whilst GSTs have previously been associated with development of aphid resistance to synthetic insecticides, the findings described here highlight a novel function as both an elicitor and suppressor of plant defense when delivered into host tissues. PMID:27536306

  2. Pea aphid promotes amino acid metabolism both in Medicago truncatula and bacteriocytes to favor aphid population growth under elevated CO2.

    PubMed

    Guo, Huijuan; Sun, Yucheng; Li, Yuefei; Tong, Bin; Harris, Marvin; Zhu-Salzman, Keyan; Ge, Feng

    2013-10-01

    Rising atmospheric CO(2) levels can dilute the nitrogen (N) resource in plant tissue, which is disadvantageous to many herbivorous insects. Aphids appear to be an exception that warrants further study. The effects of elevated CO(2) (750 ppm vs. 390 ppm) were evaluated on N assimilation and transamination by two Medicago truncatula genotypes, a N-fixing-deficient mutant (dnf1) and its wild-type control (Jemalong), with and without pea aphid (Acyrthosiphon pisum) infestation. Elevated CO(2) increased population abundance and feeding efficiency of aphids fed on Jemalong, but reduced those on dnf1. Without aphid infestation, elevated CO(2) increased photosynthetic rate, chlorophyll content, nodule number, biomass, and pod number for Jemalong, but only increased pod number and chlorophyll content for dnf1. Furthermore, aphid infested Jemalong plants had enhanced activities of N assimilation-related enzymes (glutamine synthetase, Glutamate synthase) and transamination-related enzymes (glutamate oxalate transaminase, glutamine phenylpyruvate transaminase), which presumably increased amino acid concentration in leaves and phloem sap under elevated CO(2). In contrast, aphid infested dnf1 plants had decreased activities of N assimilation-related enzymes and transmination-related enzymes and amino acid concentrations under elevated CO(2). Furthermore, elevated CO(2) up-regulated expression of genes relevant to amino acid metabolism in bacteriocytes of aphids associated with Jemalong, but down-regulated those associated with dnf1. Our results suggest that pea aphids actively elicit host responses that promote amino acid metabolism in both the host plant and in its bacteriocytes to favor the population growth of the aphid under elevated CO(2). © 2013 John Wiley & Sons Ltd.

  3. The Potato Aphid Salivary Effector Me47 Is a Glutathione-S-Transferase Involved in Modifying Plant Responses to Aphid Infestation.

    PubMed

    Kettles, Graeme J; Kaloshian, Isgouhi

    2016-01-01

    Polyphagous aphid pests cause considerable economic damage to crop plants, primarily through the depletion of photoassimilates and transfer of viruses. The potato aphid (Macrosiphum euphorbiae) is a notable pest of solanaceous crops, however, the molecular mechanisms that underpin the ability to colonize these hosts are unknown. It has recently been demonstrated that like other aphid species, M. euphorbiae injects a battery of salivary proteins into host plants during feeding. It is speculated that these proteins function in a manner analagous to secreted effectors from phytopathogenic bacteria, fungi and oomycetes. Here, we describe a novel aphid effector (Me47) which was identified from the potato aphid salivary secretome as a putative glutathione-S-transferase (GST). Expression of Me47 in Nicotiana benthamiana enhanced reproductive performance of green peach aphid (Myzus persicae). Similarly, delivery of Me47 into leaves of tomato (Solanum lycopersicum) by Pseudomonas spp. enhanced potato aphid fecundity. In contrast, delivery of Me47 into Arabidopsis thaliana reduced GPA reproductive performance, indicating that Me47 impacts the outcome of plant-aphid interactions differently depending on the host species. Delivery of Me47 by the non-pathogenic Pseudomonas fluorescens revealed that Me47 protein or activity triggers defense gene transcriptional upregulation in tomato but not Arabidopsis. Recombinant Me47 was purified and demonstrated to have GST activity against two specific isothiocyanates (ITCs), compounds implicated in herbivore defense. Whilst GSTs have previously been associated with development of aphid resistance to synthetic insecticides, the findings described here highlight a novel function as both an elicitor and suppressor of plant defense when delivered into host tissues.

  4. The significance of gut sucrase activity for osmoregulation in the pea aphid, Acyrthosiphon pisum.

    PubMed

    Karley, A J; Ashford, D A; Minto, L M; Pritchard, J; Douglas, A E

    2005-12-01

    The osmotic pressure of the body fluids of aphids is lower than in their diet of plant phloem sap. It is hypothesised that aphids reduce the osmotic pressure of ingested food by sucrase-mediated hydrolysis of dietary sucrose to glucose and fructose, and the polymerisation of glucose into oligosaccharides of low osmotic pressure per hexose unit. To test this hypothesis, the impact of the alpha-glucosidase inhibitor acarbose on the sugar relations and osmoregulation of aphids was explored. Acarbose inhibited sucrase activity in gut homogenates and the production of monosaccharides and oligosaccharides in the honeydew of live aphids. Acarbose caused an increase in the haemolymph osmotic pressure for aphids reared on a diet (containing 0.75 M sucrose) hyperosmotic to the haemolymph and not on the isoosmotic diet containing 0.2 M sucrose. It did not affect aphid feeding rate over 2 days, except at high concentrations on 0.75 M sucrose diet, and this may have been a secondary consequence of osmotic dysfunction. Acarbose-treated aphids died prematurely. With 5 microM dietary acarbose, mean survivorship on 0.2 M sucrose diet was 4.2 days, not significantly different from starved aphids, indicating that, although these aphids fed, they were deprived of utilisable carbon; and on 0.75 M sucrose diet, mean survivorship was just 2.8 days, probably as a consequence of osmotic failure. It is concluded that the aphid gut sucrase activity is essential for osmoregulation of aphids ingesting food hyperosmotic to their body fluids.

  5. Aphid Infestation Increases Fusarium langsethiae and T-2 and HT-2 Mycotoxins in Wheat.

    PubMed

    Drakulic, Jassy; Ajigboye, Olubukola; Swarup, Ranjan; Bruce, Toby; Ray, Rumiana V

    2016-11-15

    Fusarium langsethiae is a fungal pathogen of cereal crops that is an increasing problem in northern Europe, but much of its epidemiology is poorly understood. The species produces the mycotoxins T-2 and HT-2, which are highly toxic. It was hypothesized that grain aphids, Sitobion avenae, may transmit F. langsethiae inoculum between wheat plants, and a series of transmission experiments and volatile chemical analyses was performed to test this. Manual translocation of aphids from inoculated to uninfected hosts resulted in pathogen DNA accumulation in hosts. However, the free movement of wingless aphids from infected to healthy plants did not. The addition of winged aphids reared on F. langsethiae-inoculated wheat seedlings to wheat plants also did not achieve successful pathogen transfer. While our data suggested that aphid transmission of the pathogen was not very efficient, we observed an increase in disease when aphids were present. After seedling inoculation, an increase in pathogen DNA accumulation in seedling leaves was observed upon treatment with aphids. Furthermore, the presence of aphids on wheat plants with F. langsethiae-inoculated ears not only led to a rise in the amount of F. langsethiae DNA in infected grain but also to an increase in the concentrations of T-2 and HT-2 toxins, with more than 3-fold higher toxin levels than diseased plants without aphids. This work highlights that aphids increase the susceptibility of wheat host plants to F. langsethiae and that aphid infestation is a risk factor for accumulating increased levels of T-2 and HT-2 in wheat products.

  6. Plant genetic variation mediates an indirect ecological effect between belowground earthworms and aboveground aphids.

    PubMed

    Singh, Akanksha; Braun, Julia; Decker, Emilia; Hans, Sarah; Wagner, Agnes; Weisser, Wolfgang W; Zytynska, Sharon E

    2014-10-21

    Interactions between aboveground and belowground terrestrial communities are often mediated by plants, with soil organisms interacting via the roots and aboveground organisms via the shoots and leaves. Many studies now show that plant genetics can drive changes in the structure of both above and belowground communities; however, the role of plant genetic variation in mediating aboveground-belowground interactions is still unclear. We used an earthworm-plant-aphid model system with two aphid species (Aphis fabae and Acyrthosiphon pisum) to test the effect of host-plant (Vicia faba) genetic variation on the indirect interaction between the belowground earthworms (Eisenia veneta) on the aboveground aphid populations. Our data shows that host-plant variety mediated an indirect ecological effect of earthworms on generalist black bean aphids (A. fabae), with earthworms increasing aphid growth rate in three plant varieties but decreasing it in another variety. We found no effect of earthworms on the second aphid species, the pea aphid (A. pisum), and no effect of competition between the aphid species. Plant biomass was increased when earthworms were present, and decreased when A. pisum was feeding on the plant (mediated by plant variety). Although A. fabae aphids were influenced by the plants and worms, they did not, in turn, alter plant biomass. Previous work has shown inconsistent effects of earthworms on aphids, but we suggest these differences could be explained by plant genetic variation and variation among aphid species. This study demonstrates that the outcome of belowground-aboveground interactions can be mediated by genetic variation in the host-plant, but depends on the identity of the species involved.

  7. Soybean aphid (Hemiptera: Aphididae) response to soybean plant defense: stress levels, tradeoffs, and cross-virulence.

    PubMed

    Enders, Laramy; Bickel, Ryan; Brisson, Jennifer; Heng-Moss, Tiffany; Siegfried, Blair; Zera, Anthony; Miller, Nick

    2014-02-01

    A variety of management methods to control the soybean aphid (Aphis glycines Matsumura) have been investigated since its invasion into North America in 2000, among them plant resistance has emerged as a viable option for reducing aphid damage to soybeans and preventing outbreaks. Plant resistance methods often use natural soybean plant defenses that impose stress on aphids by reducing fitness and altering behavior. Research efforts have heavily focused on identification and development of aphid resistant soybean varieties, leaving much unknown about soybean aphid response to stressful host plant defenses. In this study, we aimed to 1) evaluate lifetime fitness consequences and phenotypic variation in response to host plant-induced stress and 2) investigate whether trade-offs involving fitness costs and/or cross-virulence to multiple antibiotic soybean varieties exists. We compared aphid survival and reproduction during and after a short period of exposure to soybeans with the Rag2 resistance gene and measured aphid clonal variation in response to Rag2 soybeans. In addition, we measured the performance of Rag2 virulent and avirulent aphids on five soybean varieties with various forms of antibiotic resistance. Our results indicate that plant defenses impose high levels of stress and have long-term fitness consequences, even after aphids are removed from resistant plants. We identified one aphid clone that was able to colonize Rag2 among the seven clones tested, suggesting that virulent genotypes may be prevalent in natural populations. Finally, although we did not find evidence of cross-virulence to multiple antibiotic soybean varieties, our results suggest independent mechanisms of aphid virulence to Rag1 and Rag2 that may involve fitness costs.

  8. Climate warming may increase aphids' dropping probabilities in response to high temperatures.

    PubMed

    Ma, Gang; Ma, Chun-Sen

    2012-11-01

    Dropping off is considered an anti-predator behavior for aphids since previous studies have shown that it reduces the risk of predation. However, little attention is paid to dropping behavior triggered by other external stresses such as daytime high temperatures which are predicted to become more frequent in the context of climate warming. Here we defined a new parameter, drop-off temperature (DOT), to describe the critical temperature at which an aphid drops off its host plant when the ambient temperature increases gradually and slowly. Detailed studies were conducted to reveal effects of short-term acclimation (temperature, exposure time at high-temperature and starvation) on DOT of an aphid species, Sitobion avenae. Our objectives were to test if the aphids dropped off host plant to avoid high temperatures and how short-term acclimation affected the aphids' dropping behavior in response to heat stress. We suggest that dropping is a behavioral thermoregulation to avoid heat stress, since aphids started to move before they dropped off and the dropped aphids were still able to control their muscles prior to knockdown. The adults starved for 12 h had higher DOT values than those that were unstarved or starved for 6 h, and there was a trade-off between behavioral thermoregulation and energy acquisition. Higher temperatures and longer exposure times at high temperatures significantly lowered the aphids' DOT, suggested that the aphids avoid heat stress by dropping when exposed to high temperatures. Climate warming may therefore increase the aphids' dropping probabilities and consequently affect the aphids' individual development and population growth.

  9. Plant genetic variation mediates an indirect ecological effect between belowground earthworms and aboveground aphids

    PubMed Central

    2014-01-01

    Background Interactions between aboveground and belowground terrestrial communities are often mediated by plants, with soil organisms interacting via the roots and aboveground organisms via the shoots and leaves. Many studies now show that plant genetics can drive changes in the structure of both above and belowground communities; however, the role of plant genetic variation in mediating aboveground-belowground interactions is still unclear. We used an earthworm-plant-aphid model system with two aphid species (Aphis fabae and Acyrthosiphon pisum) to test the effect of host-plant (Vicia faba) genetic variation on the indirect interaction between the belowground earthworms (Eisenia veneta) on the aboveground aphid populations. Results Our data shows that host-plant variety mediated an indirect ecological effect of earthworms on generalist black bean aphids (A. fabae), with earthworms increasing aphid growth rate in three plant varieties but decreasing it in another variety. We found no effect of earthworms on the second aphid species, the pea aphid (A. pisum), and no effect of competition between the aphid species. Plant biomass was increased when earthworms were present, and decreased when A. pisum was feeding on the plant (mediated by plant variety). Although A. fabae aphids were influenced by the plants and worms, they did not, in turn, alter plant biomass. Conclusions Previous work has shown inconsistent effects of earthworms on aphids, but we suggest these differences could be explained by plant genetic variation and variation among aphid species. This study demonstrates that the outcome of belowground-aboveground interactions can be mediated by genetic variation in the host-plant, but depends on the identity of the species involved. PMID:25331082

  10. Indian Bt Cotton Varieties Do Not Affect the Performance of Cotton Aphids

    PubMed Central

    Lawo, Nora C.; Wäckers, Felix L.; Romeis, Jörg

    2009-01-01

    Cotton varieties expressing Cry proteins derived from the soil bacterium Bacillus thuringiensis (Bt) are grown worldwide for the management of pest Lepidoptera. To prevent non-target pest outbreaks and to retain the biological control function provided by predators and parasitoids, the potential risk that Bt crops may pose to non-target arthropods is addressed prior to their commercialization. Aphids play an important role in agricultural systems since they serve as prey or host to a number of predators and parasitoids and their honeydew is an important energy source for several arthropods. To explore possible indirect effects of Bt crops we here examined the impact of Bt cotton on aphids and their honeydew. In climate chambers we assessed the performance of cotton aphids, Aphis gossypii Glover (Hemiptera: Aphididae) when grown on three Indian Bt (Cry1Ac) cotton varieties (MECH 12, MECH 162, MECH 184) and their non-transformed near isolines. Furthermore, we examined whether aphids pick up the Bt protein and analyzed the sugar composition of aphid honeydew to evaluate its suitability for honeydew-feeders. Plant transformation did not have any influence on aphid performance. However, some variation was observed among the three cotton varieties which might partly be explained by the variation in trichome density. None of the aphid samples contained Bt protein. As a consequence, natural enemies that feed on aphids are not exposed to the Cry protein. A significant difference in the sugar composition of aphid honeydew was detected among cotton varieties as well as between transformed and non-transformed plants. However, it is questionable if this variation is of ecological relevance, especially as honeydew is not the only sugar source parasitoids feed on in cotton fields. Our study allows the conclusion that Bt cotton poses a negligible risk for aphid antagonists and that aphids should remain under natural control in Bt cotton fields. PMID:19279684

  11. Sugarcane Aphid (Hemiptera: Aphididae): A New Pest on Sorghum in North America

    PubMed Central

    Bowling, Robert D.; Brewer, Michael J.; Kerns, David L.; Gordy, John; Seiter, Nick; Elliott, Norman E.; Buntin, G. David; Way, M. O.; Royer, T. A.; Biles, Stephen; Maxson, Erin

    2016-01-01

    In 2013, the sugarcane aphid, Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae), a new invasive pest of sorghum species in North America, was confirmed on sorghum in 4 states and 38 counties in the United States. In 2015, the aphid was reported on sorghum in 17 states and over 400 counties as well as all sorghum-producing regions in Mexico. Ability to overwinter on living annual and perennial hosts in southern sorghum-producing areas and wind-aided movement of alate aphids appear to be the main factors in its impressive geographic spread in North America. Morphological characteristics of the sugarcane aphid include dark tarsi, cornicles, and antennae, allowing easy differentiation from other aphids on the crop. Sugarcane aphid damages sorghum by removing sap and covering plants with honeydew, causing general plant decline and yield loss. Honeydew and sooty mold can disrupt harvesting. The aphid’s high reproductive rate on susceptible sorghum hybrids has resulted in reports of yield loss ranging from 10% to greater than 50%. In response, a combination of research-based data and field observations has supported development of state extension identification, scouting, and treatment guides that aid in initiating insecticide applications to prevent yield losses. Highly efficacious insecticides have been identified and when complemented by weekly scouting and use of thresholds, economic loss by sugarcane aphid can be minimized. Some commercial sorghum hybrids are partially resistant to the aphid, and plant breeders have identified other lines with sugarcane aphid resistance. A very diverse community of predators and parasitoids of sugarcane aphid has been identified, and their value to limit sugarcane aphid population growth is under investigation. PMID:28446991

  12. Alfalfa living mulch advances biological control of soybean aphid.

    PubMed

    Schmidt, Nicholas P; O'neal, Matthew E; Singer, Jeremy W

    2007-04-01

    Despite evidence for biological control in North America, outbreaks of the invasive soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), continue to occur on soybean (Glycine max L. Merr.). Our objectives were to determine whether natural enemies delay aphid establishment and limit subsequent population growth and whether biological control can be improved by altering the within-field habitat. We hypothesized that a living mulch would increase the abundance of the aphidophagous community in soybean and suppress A. glycines establishment and population growth. We measured natural enemy and A. glycines abundance in soybean grown with and without an alfalfa (Medicago sativa L.) living mulch. Soybean grown with an alfalfa living mulch had 45% more natural enemies and experienced a delay in A. glycines establishment that resulted in lower peak populations. From our experiments, we concluded that the current natural enemy community in Iowa can delay A. glycines establishment, and an increase in aphidophagous predator abundance lowered the rate of A. glycines population growth preventing economic populations (i.e., below the current economic threshold) from occurring. Incorporation of a living mulch had an unexpected impact on A. glycines population growth, lowering the aphids' intrinsic rate of growth, thus providing a bottom-up suppression of A. glycines. We suggest future studies of living mulches or cover crops for A. glycines management should address both potential sources of suppression. Furthermore, our experience suggests that more consistent biological control of A. glycines may be possible with even partial resistance that slows but does not prevent reproduction.

  13. Genetic Control of Contagious Asexuality in the Pea Aphid

    PubMed Central

    Jaquiéry, Julie; Stoeckel, Solenn; Larose, Chloé; Nouhaud, Pierre; Rispe, Claude; Mieuzet, Lucie; Bonhomme, Joël; Mahéo, Frédérique; Legeai, Fabrice; Gauthier, Jean-Pierre; Prunier-Leterme, Nathalie; Tagu, Denis; Simon, Jean-Christophe

    2014-01-01

    Although evolutionary transitions from sexual to asexual reproduction are frequent in eukaryotes, the genetic bases of such shifts toward asexuality remain largely unknown. We addressed this issue in an aphid species where both sexual and obligate asexual lineages coexist in natural populations. These sexual and asexual lineages may occasionally interbreed because some asexual lineages maintain a residual production of males potentially able to mate with the females produced by sexual lineages. Hence, this species is an ideal model to study the genetic basis of the loss of sexual reproduction with quantitative genetic and population genomic approaches. Our analysis of the co-segregation of ∼300 molecular markers and reproductive phenotype in experimental crosses pinpointed an X-linked region controlling obligate asexuality, this state of character being recessive. A population genetic analysis (>400-marker genome scan) on wild sexual and asexual genotypes from geographically distant populations under divergent selection for reproductive strategies detected a strong signature of divergent selection in the genomic region identified by the experimental crosses. These population genetic data confirm the implication of the candidate region in the control of reproductive mode in wild populations originating from 700 km apart. Patterns of genetic differentiation along chromosomes suggest bidirectional gene flow between populations with distinct reproductive modes, supporting contagious asexuality as a prevailing route to permanent parthenogenesis in pea aphids. This genetic system provides new insights into the mechanisms of coexistence of sexual and asexual aphid lineages. PMID:25473828

  14. Intra versus interspecific interactions of ladybeetles (Coleoptera: Coccinellidae) attacking aphids.

    PubMed

    Evans, Edward W

    1991-09-01

    The nature and relative strengths of intra versus interspecific interactions among foraging ladybeetle larvae were studied experimentally by measuring short-term growth rates of predators and reductions in population sizes of prey in laboratory microcosms. In these microcosms, ladybeetle larvae foraged singly or as conspecific or heterospecific pairs, for pea aphids on bean plants over a two-day period. Similarly sized third instar larvae ofHippodamia convergens andH. tredecimpunctata, H. convergens andH. sinuata, andH. convergens andCoccinella septempunctata, were tested in experiments designed to ensure that paired larvae experienced moderate competition. Interspecific competition in these experiments did not differ significantly from intraspecific competition, in that an individual's weight gain did not depend on whether its competitor was heterospecific or conspecific. Furthermore, aphid populations were reduced equally by heterospecific and conspecific pairs. These results suggest that there is little or no difference between intra and interspecific interactions among larvae of these ladybeetles when two similarly sized individuals co-occur on a host plant. Thus, the species diversityper se of assemblages of ladybeetle larvae may have little influence over the short term on the reduction of aphid populations by ladybeetle predation.

  15. Wild Solanum resistance to aphids: antixenosis or antibiosis?

    PubMed

    Le Roux, Vincent; Dugravot, Sébastien; Campan, Erick; Dubois, Françoise; Vincent, Charles; Giordanengo, Philippe

    2008-04-01

    The type (antixenosis or antibiosis) of resistance against the aphids Myzus persicae (Sulzer) and Macrosiphum euphorbiae (Thomas) was characterized for the wild tuber-bearing potatoes, Solanum chomatophilum Bitter and Solanum stoloniferum Schltdl. & Bouché through behavioral (olfactometry and electrical penetration graph) and physiological studies. In dual-choice assays, only S. stoloniferum exerted attraction to M. euphorbiae. This ruled out the possibility that plant volatiles of S. chomatophilum and S. stoloniferum may contribute to the high resistance expressed. In electrical penetration graph experiments, aphids feeding on S. stoloniferum showed increased salivation phases, whereas phloem ingestion was drastically reduced for both aphid species. Because reaching phloem elements was not delayed in both species, the resistance mechanism was phloem-located. The antixenosis exhibited by S. stoloniferum was similar on young and mature leaves. S. chomatophilum also showed phloem-located antixenosis against M. persicae. In contrast, M. euphorbiae had no difficulty to reach S. chomatophilum phloem tissues and to ingest sap. S. chomatophilum resistance against M. euphorbiae was antibiosis and only expressed in mature leaves, where a complete nymphal mortality was observed.

  16. The chemical signatures underlying host plant discrimination by aphids.

    PubMed

    Hopkins, David P; Cameron, Duncan D; Butlin, Roger K

    2017-08-17

    The diversity of phytophagous insects is largely attributable to speciation involving shifts between host plants. These shifts are mediated by the close interaction between insects and plant metabolites. However, there has been limited progress in understanding the chemical signatures that underlie host preferences. We use the pea aphid (Acyrthosiphon pisum) to address this problem. Host-associated races of pea aphid discriminate between plant species in race-specific ways. We combined metabolomic profiling of multiple plant species with behavioural tests on two A. pisum races, to identify metabolites that explain variation in either acceptance or discrimination. Candidate compounds were identified using tandem mass spectrometry. Our results reveal a small number of compounds that explain a large proportion of variation in the differential acceptability of plants to A. pisum races. Two of these were identified as L-phenylalanine and L-tyrosine but it may be that metabolically-related compounds directly influence insect behaviour. The compounds implicated in differential acceptability were not related to the set correlated with general acceptability of plants to aphids, regardless of host race. Small changes in response to common metabolites may underlie host shifts. This study opens new opportunities for understanding the mechanistic basis of host discrimination and host shifts in insects.

  17. Relative importance of predators and parasitoids for cereal aphid control.

    PubMed Central

    Schmidt, Martin H; Lauer, Andreas; Purtauf, Tobias; Thies, Carsten; Schaefer, Matthias; Tscharntke, Teja

    2003-01-01

    Field experiments with manipulations of natural enemies of plant-feeding insects may show how a diverse enemy group ensures an important ecosystem function such as naturally occurring biological pest control. We studied cereal aphid populations in winter wheat under experimentally reduced densities of: (i) ground-dwelling generalist predators (mostly spiders, carabid and staphylinid beetles); (ii) flying predators (coccinellid beetles, syrphid flies, gall midges, etc.) and parasitoids (aphidiid wasps), and a combination of (i) and (ii), compared with open controls. Aphid populations were 18% higher at reduced densities of ground-dwelling predators, 70% higher when flying predators and parasitoids were removed, and 172% higher on the removal of both enemy groups. Parasitoid wasps probably had the strongest effect, as flying predators occurred only in negligible densities. The great importance of parasitism is a new finding for aphid control in cereal fields. In conclusion, a more detailed knowledge of the mechanisms of natural pest control would help to develop environmentally sound crop management with reduced pesticide applications. PMID:14561303

  18. Genome-wide detection of genetic loci associated with soybean aphid resistance in soybean germplasm PI 603712

    USDA-ARS?s Scientific Manuscript database

    Soybean aphid (Aphis glycines Matsumura) has become one of the major pests of soybean (Glycine max (L.) Merr.) in North America since 2000. At least four biotypes of soybean aphid have been confirmed in the United States. Genetic characterization of new sources of soybean aphid resistance will facil...

  19. Tangible benefits of the pea aphid genome sequencing in proteomics research: enhancements in protein identification, data incorporation, and evaluation criteria

    USDA-ARS?s Scientific Manuscript database

    The pea aphid, Acyrthosiphon pisum, is an important agricultural pest and a model system for numerous aspects of aphid biology, including sexual and asexual reproduction, bacterial endosymbiosis, insecticide resistance, and the evolution of aphid and plant host interactions. Recently, its complete ...

  20. Maintaining genetic diversity and population panmixia through dispersal and not gene flow in a Holocyclic heteroecious aphid species

    USDA-ARS?s Scientific Manuscript database

    Heteroecious holocyclic aphids alternate between sexual and asexual reproduction on primary and secondary hosts, respectively. Most of these aphids are generalists, but the aphid specialist Aphis glycines survives only on the primary host buckthorn (Rhamnus spp.) and the secondary host soybean (Gly...

  1. A protein from the salivary glands of the pea aphid, Acyrthosiphon pisum, is essential in feeding on a host plant

    USDA-ARS?s Scientific Manuscript database

    In feeding, aphids inject saliva into plant tissues, gaining access to phloem sap and eliciting (and sometimes overcoming) plant responses. We are examining the involvement, in this aphid-plant interaction, of individual aphid proteins and enzymes, as identified in a salivary gland cDNA library. Her...

  2. Impact of aphid alarm pheromone release on virus transmission efficiency: When pest control strategy could induce higher virus dispersion.

    PubMed

    Lin, Fang-Jing; Bosquée, Emilie; Liu, Ying-Jie; Chen, Ju-Lian; Yong, Liu; Francis, Frédéric

    2016-09-01

    Aphids cause serious damages to crops not only by tacking sap but also by transmitting numerous viruses. To develop biological control, the aphid alarm pheromone, namely E-β-farnesene (EβF), has been demonstrated to be efficient to repel aphids and as attract beneficials, making it a potential tool to control aphid pests. Considering aphids also as virus vectors, changes of their behavior could also interfere with the virus acquisition and transmission process. Here, a combination of two aphid species and two potato virus models were selected to test the influence of EβF release on aphid and virus dispersion under laboratory conditions. EβF release was found to significantly decrease the population of Myzus persicae and Macrosiphum euphorbiae around the infochemical releaser but simultaneously also increasing the dispersal of Potato Virus Y (PVY). At the opposite, no significant difference for Potato Leaf Roll Virus (PLRV) transmission efficiency was observed with similar aphid alarm pheromone releases for none of the aphid species. These results provide some support to carefully consider infochemical releasers not only for push-pull strategy and pest control but also to include viral disease in a the plant protection to aphids as they are also efficient virus vectors. Impact of aphid kinds and transmission mechanisms will be discussed according to the large variation found between persistent and non persistent potato viruses and interactions with aphids and related infochemicals. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Comparative metabolite profiling of foxglove aphids (Aulacorthum solani Kaltenbach) on leaves of resistant and susceptible soybean strains.

    PubMed

    Sato, Dan; Sugimoto, Masahiro; Akashi, Hiromichi; Tomita, Masaru; Soga, Tomoyoshi

    2014-04-01

    Aphid infestations can cause severe decreases in soybean (Glycine max [L.] Merr.) yield. Since planting aphid-resistant soybean strains is a promising approach for pest control, understanding the resistance mechanisms employed by aphids is of considerable importance. We compared aphid resistance in seven soybean strains and found that strain Tohoku149 was the most resistant to the foxglove aphid, Aulacorthum solani Kaltenbach. We subsequently analyzed the metabolite profiles of aphids cultured on the leaves of resistant and susceptible soybean strains using capillary electrophoresis-time-of-flight mass spectrometry. Our findings showed that the metabolite profiles of several amino acids, glucose 6-phosphate, and components of the tricarboxylic acid cycle were similar in aphids reared on Tohoku149 leaves and in aphids maintained under conditions of starvation, suggesting that Tohoku149 is more resistant to aphid feeding. Compared to susceptible strains, we also found that two methylated metabolites, S-methylmethionine and trigonelline, were either not detected or decreased in aphids reared on Tohoku149 plants. Since these metabolites function as important sulfur transporters in phloem sap and osmoprotectants involved in salt and drought stress, respectively, aphid-resistance is considered to be related to sulfur metabolism and methylation. These results contribute to an increase in our understanding of soybean aphid resistance mechanisms at the molecular level.

  4. 77 FR 46373 - Field Release of Aphelinus glycinis for the Biological Control of the Soybean Aphid in the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-03

    ... the Biological Control of the Soybean Aphid in the Continental United States; Availability of an... release of Aphelinus glycinis for the biological control of the soybean aphid, Aphis glycines, in the...-2323. SUPPLEMENTARY INFORMATION: Background The soybean aphid, Aphis glycinis, which is native to...

  5. Soybean Aphid Infestation Induces Changes in Fatty Acid Metabolism in Soybean

    PubMed Central

    Kanobe, Charles; McCarville, Michael T.; O’Neal, Matthew E.; Tylka, Gregory L.; MacIntosh, Gustavo C.

    2015-01-01

    The soybean aphid (Aphis glycines Matsumura) is one of the most important insect pests of soybeans in the North-central region of the US. It has been hypothesized that aphids avoid effective defenses by inhibition of jasmonate-regulated plant responses. Given the role fatty acids play in jasmonate-induced plant defenses, we analyzed the fatty acid profile of soybean leaves and seeds from aphid-infested plants. Aphid infestation reduced levels of polyunsaturated fatty acids in leaves with a concomitant increase in palmitic acid. In seeds, a reduction in polyunsaturated fatty acids was associated with an increase in stearic acid and oleic acid. Soybean plants challenged with the brown stem rot fungus or with soybean cyst nematodes did not present changes in fatty acid levels in leaves or seeds, indicating that the changes induced by aphids are not a general response to pests. One of the polyunsaturated fatty acids, linolenic acid, is the precursor of jasmonate; thus, these changes in fatty acid metabolism may be examples of “metabolic hijacking” by the aphid to avoid the induction of effective defenses. Based on the changes in fatty acid levels observed in seeds and leaves, we hypothesize that aphids potentially induce interference in the fatty acid desaturation pathway, likely reducing FAD2 and FAD6 activity that leads to a reduction in polyunsaturated fatty acids. Our data support the idea that aphids block jasmonate-dependent defenses by reduction of the hormone precursor. PMID:26684003

  6. Identification of conditions for successful aphid control by ladybirds in greenhouses

    USDA-ARS?s Scientific Manuscript database

    As part of my research on the mass production and augmentative release of ladybirds, I reviewed the primary research literature to test the prediction that ladybirds are effective aphid predators in greenhouses. Aphid population reduction exceeded 50% in most studies and ladybird release rates usual...

  7. (E)-β-farnesene synthase genes affect aphid (Myzus persicae) infestation in tobacco (Nicotiana tabacum).

    PubMed

    Yu, Xiudao; Jones, Huw D; Ma, Youzhi; Wang, Genping; Xu, Zhaoshi; Zhang, Baoming; Zhang, Yongjun; Ren, Guangwei; Pickett, John A; Xia, Lanqin

    2012-03-01

    Aphids are major agricultural pests which cause significant yield losses of the crop plants each year. (E)-β-farnesene (EβF) is the alarm pheromone involved in the chemical communication between aphids and particularly in the avoidance of predation. In the present study, two EβF synthase genes were isolated from sweet wormwood and designated as AaβFS1 and AaβFS2, respectively. Overexpression of AaβFS1 or AaβFS2 in tobacco plants resulted in the emission of EβF ranging from 1.55 to 4.65 ng/day/g fresh tissues. Tritrophic interactions involving the peach aphids (Myzus persicae), predatory lacewings (Chrysopa septempunctata) demonstrated that the transgenic tobacco expressing AaβFS1 and AaβFS2 could repel peach aphids, but not as strongly as expected. However, AaβFS1 and AaβFS2 lines exhibited strong and statistically significant attraction to lacewings. Further experiments combining aphids and lacewing larvae in an octagon arrangement showed transgenic tobacco plants could repel aphids and attract lacewing larvae, thus minimizing aphid infestation. Therefore, we demonstrated a potentially valuable strategy of using EβF synthase genes from sweet wormwood for aphid control in tobacco or other economic important crops in an environmentally benign way.

  8. Outbreak of sorghum/sugarcane aphid on sorghum: First detections, distribution, and notes on management

    USDA-ARS?s Scientific Manuscript database

    An outbreak of an invasive aphid was discovered damaging grain sorghum in Texas and neighboring states in 2013. It may be a new variant of sugarcane aphid, Melanaphis sacchari, that has a high preference for sorghum, or a very closely related species (M. sorghi). We designate it sorghum/sugarcane ...

  9. Characterization and genetics of multiple soybean aphid biotype resistance in five soybean plant introductions

    USDA-ARS?s Scientific Manuscript database

    Soybean aphid (Aphis glycines Matsumura) is the most important soybean [Glycine max (L.) Merr.] insect pest in the USA. The objectives of this study were to characterize the resistance expressed in the five plant introductions (PIs) to four soybean aphid biotypes, determine the mode of resistance in...

  10. Performance and prospects of Rag genes for management of soybean aphid

    USDA-ARS?s Scientific Manuscript database

    The soybean aphid, Aphis glycines Matsumura, is an invasive insect pest of soybean [Glycine max (L.) Merr.] in North America, and it has led to extensive insecticide use in northern soybean-growing regions there. Host-plant resistance is one potential alternative strategy for managing soybean aphid...

  11. Distribution of Redwood Caused by the Balsam Woolly Aphid in Fraser Fir of North Carolina

    Treesearch

    Gene D. Amman

    1970-01-01

    Examination of 5-foot sections of felled Fraser fir, Abies fraseri (Pursh) Poir., trees infested or killed by the balsam woolly aphid, Adelges piceae (Ratzeburg), revealed that the height of the first annual ring of aphid-caused redwood increased as the height of the trees increased. The number of red rings varied from two in a...

  12. GroEL from the endosymbiont Buchnera aphidicola betrays the aphid by triggering plant defense.

    PubMed

    Chaudhary, Ritu; Atamian, Hagop S; Shen, Zhouxin; Briggs, Steven P; Kaloshian, Isgouhi

    2014-06-17

    Aphids are sap-feeding plant pests and harbor the endosymbiont Buchnera aphidicola, which is essential for their fecundity and survival. During plant penetration and feeding, aphids secrete saliva that contains proteins predicted to alter plant defenses and metabolism. Plants recognize microbe-associated molecular patterns and induce pattern-triggered immunity (PTI). No aphid-associated molecular pattern has yet been identified. By mass spectrometry, we identified in saliva from potato aphids (Macrosiphum euphorbiae) 105 proteins, some of which originated from Buchnera, including the chaperonin GroEL. Because GroEL is a widely conserved bacterial protein with an essential function, we tested its role in PTI. Applying or infiltrating GroEL onto Arabidopsis (Arabidopsis thaliana) leaves induced oxidative burst and expression of PTI early marker genes. These GroEL-induced defense responses required the known coreceptor BRASSINOSTEROID INSENSITIVE 1-ASSOCIATED RECEPTOR KINASE 1. In addition, in transgenic Arabidopsis plants, inducible expression of groEL activated PTI marker gene expression. Moreover, Arabidopsis plants expressing groEL displayed reduced fecundity of the green peach aphid (Myzus persicae), indicating enhanced resistance against aphids. Furthermore, delivery of GroEL into tomato (Solanum lycopersicum) or Arabidopsis through Pseudomonas fluorescens, engineered to express the type III secretion system, also reduced potato aphid and green peach aphid fecundity, respectively. Collectively our data indicate that GroEL is a molecular pattern that triggers PTI.

  13. Towards efficient multi-scale methods for monitoring sugarcane aphid infestations in sorghum

    USDA-ARS?s Scientific Manuscript database

    We discuss approaches and issues involved with developing optimal monitoring methods for sugarcane aphid infestations (SCA) in grain sorghum. We discuss development of sequential sampling methods that allow for estimation of the number of aphids per sample unit, and statistical decision making rela...

  14. Population genetics of the sugarcane aphid, Melanaphis sacchari (Zehntner), in the continental US

    USDA-ARS?s Scientific Manuscript database

    The sugarcane aphid (SCA), Melanaphis sacchari, was reported as a damaging pest of sorghum in the United States (U.S.) for the first time in 2013. However, this aphid is not new to the U.S. Since 1920s up until 2013 SCA have occurred on sugarcane in Florida and later in Louisiana, causing minimal ...

  15. Effects of single and combined heavy metals and their chelators on aphid performance and preferences.

    PubMed

    Stolpe, Clemens; Müller, Caroline

    2016-12-01

    When present at elevated levels in the environment, heavy metals are toxic for most organisms. However, so-called hyperaccumulator plants tolerate heavy metals and use chelators for their internal long-distance transport. Thus, phloem-sucking insects may come in contact with the chelated metals. In the present study, the effects of individual and combined heavy metals, zinc (Zn) and cadmium (Cd), as well as of common chelators, nicotianamine and phytochelatin, were investigated on the performance, preferences, and metal accumulation of the generalist aphid Myzus persicae, using artificial diets. Added Zn increased aphid growth, whereas Cd reduced the survival of aphids. Chelators had neither protective nor negative effects on aphids. The combination of the 2 heavy metals in chelated or nonchelated form caused a potentiation effect that led to an extinction of the aphids within less than 2 wk, before they could reproduce. Both Cd and Zn accumulated in the aphids, indicating a possible biomagnification. In choice assays, aphids preferred diets amended with Zn with or without nicotianamine compared to a control diet. In contrast, a Cd-containing diet led to neither attraction nor aversion. The present study provides insight into how mixtures of heavy metals and their chelators influence the life history of a generalist aphid. The results have implications for the use of phytoremediation to remove heavy metals from contaminated soils. Environ Toxicol Chem 2016;35:3023-3030. © 2016 SETAC. © 2016 SETAC.

  16. Aphid population fluctuations and patterns of species dominance in Puerto Rico

    USDA-ARS?s Scientific Manuscript database

    Technical Abstract: Papaya ringspot virus (PRSV) is a non-persistently transmitted virus affecting papaya and cucurbit production worldwide. Papaya is not known to be colonized by any species of aphid, but multiple species can transmit the virus. That means that transmission depends on aphid populat...

  17. Aphids and parasitoids in wheat and nearby canola fields in central Oklahoma

    USDA-ARS?s Scientific Manuscript database

    In central Oklahoma, winter canola has recently become the primary rotational winter crop with wheat. Annual aphid pest outbreaks in canola have resulted in widespread insecticide applications. Insect parasitoids, which frequently suppress aphids in nearby wheat, may move to canola due to the larg...

  18. Safeguarding world wheat and barley production against Russian wheat aphid: An international pre-breeding initiative

    USDA-ARS?s Scientific Manuscript database

    The Russian wheat aphid (RWA), Diuraphis noxia, is one of the most damaging insect pests of wheat and barley throughout the World. This aphid, although is not yet present in Australia, is extremely damaging with up to 70% yield loses in wheat and barley producing lands, causing significant financia...

  19. Identification of Resistance to the Large Raspberry Aphid in Black Raspberry

    USDA-ARS?s Scientific Manuscript database

    The large raspberry aphid, Amphorophora agathonica Hottes, is an important vector of viruses in Rubus across North America. Although breeding for aphid resistance has long been recognized as an important tool for protecting red raspberries from viral infection, this is the first report of resistance...

  20. Cursorial spiders retard initial aphid population growth at low densities in winter wheat.

    PubMed

    Birkhofer, K; Gavish-Regev, E; Endlweber, K; Lubin, Y D; von Berg, K; Wise, D H; Scheu, S

    2008-06-01

    Generalist predators contribute to pest suppression in agroecosystems. Spider communities, which form a substantial fraction of the generalist predator fauna in arable land, are characterized by two functional groups: web-building and cursorial (non-web-building) species. We investigated the relative impact of these two functional groups on a common pest (Sitobion avenae, Aphididae) in wheat by combining a molecular technique that revealed species-specific aphid consumption rates with a factorial field experiment that analyzed the impact, separately and together, of equal densities of these two spider functional groups on aphid population growth. Only cursorial spiders retarded aphid population growth in our cage experiment, but this effect was limited to the initial aphid-population growth period and low-to-intermediate aphid densities. The molecular analysis, which used aphid-specific primers to detect aphid DNA in predator species, detected the highest proportion of aphid-consuming individuals in two cursorial spiders: the foliage-dwelling Xysticus cristatus (Thomisidae) and the ground-active Pardosa palustris (Lycosidae). The results suggest that manipulating the community composition in favour of pest-consuming functional groups may be more important for improving biological control than fostering predator biodiversity per se. Agricultural management practices that specifically foster effective species or functional groups (e.g. mulching for cursorial spiders) should receive more attention in low-pesticide farming systems.

  1. Virulence of Hypocreales fungi to pecan aphids (Hemiptera: Aphididae) in the laboratory.

    USDA-ARS?s Scientific Manuscript database

    There is need for efficacious biocontrol agents for aphids in commercial orchards. As a preliminary step to this end we determined the virulence of Paecilomyces fumosoroseus to three pecan aphids Monellia caryella, Melanocallis caryaefoliae, and Monelliopsis pecanis under laboratory conditions. Ra...

  2. Identification of plant quantitative trait loci modulating a rhizobacteria-aphid indirect effect.

    PubMed

    Tétard-Jones, Catherine; Kertesz, Michael A; Preziosi, Richard F

    2012-01-01

    Plants simultaneously interact with a plethora of species both belowground and aboveground, which can result in indirect effects mediated by plants. Studies incorporating plant genetic variation indicate that indirect effects mediated by plants may be a significant factor influencing the ecology and evolution of species within a community. Here, we present findings of a Quantitative Trait Locus (QTL) mapping study, where we mapped a rhizobacteria-aphid indirect effect onto the barley genome. We measured the size of aphid populations on barley when the barley rhizosphere either was or was not supplemented with a rhizobacterial species. Using a QTL mapping subset, we located five regions of the barley genome associated with the rhizobacteria-aphid indirect effect. Rhizobacterial supplementation led to an increase in aphid population size (mapped to three barley QTL), or a decrease in aphid population size (mapped to two barley QTL). One QTL associated with plant resistance to aphids was affected by a significant QTL-by-environment interaction, because it was not expressed when rhizobacteria was supplemented. Our results indicated that rhizobacterial supplementation of barley roots led to either increased or reduced aphid population size depending on plant genotype at five barley QTL. This indicates that the direction of a rhizobacteria-aphid indirect effect could influence the selection pressure on plants, when considering species that affect plant fitness. Further research may build on the findings presented here, to identify genes within QTL regions that are involved in the indirect interaction.

  3. Identification of Plant Quantitative Trait Loci Modulating a Rhizobacteria-Aphid Indirect Effect

    PubMed Central

    Tétard-Jones, Catherine; Kertesz, Michael A.; Preziosi, Richard F.

    2012-01-01

    Plants simultaneously interact with a plethora of species both belowground and aboveground, which can result in indirect effects mediated by plants. Studies incorporating plant genetic variation indicate that indirect effects mediated by plants may be a significant factor influencing the ecology and evolution of species within a community. Here, we present findings of a Quantitative Trait Locus (QTL) mapping study, where we mapped a rhizobacteria-aphid indirect effect onto the barley genome. We measured the size of aphid populations on barley when the barley rhizosphere either was or was not supplemented with a rhizobacterial species. Using a QTL mapping subset, we located five regions of the barley genome associated with the rhizobacteria-aphid indirect effect. Rhizobacterial supplementation led to an increase in aphid population size (mapped to three barley QTL), or a decrease in aphid population size (mapped to two barley QTL). One QTL associated with plant resistance to aphids was affected by a significant QTL-by-environment interaction, because it was not expressed when rhizobacteria was supplemented. Our results indicated that rhizobacterial supplementation of barley roots led to either increased or reduced aphid population size depending on plant genotype at five barley QTL. This indicates that the direction of a rhizobacteria-aphid indirect effect could influence the selection pressure on plants, when considering species that affect plant fitness. Further research may build on the findings presented here, to identify genes within QTL regions that are involved in the indirect interaction. PMID:22844487

  4. Risk to native Uroleucon aphids (Hemiptera: Aphididae) from non-native lady beetles (Coleoptera: Coccinellidae)

    USDA-ARS?s Scientific Manuscript database

    Aphids in the genus Uroleucon Mordvilko (Hemiptera: Aphididae) are native herbivores that feed on goldenrod (Solidago spp.) and other Asteraceae in North America. The aphids are potential prey for a wide variety of natural enemies, including native and non-native species of lady beetles (Coleoptera...

  5. Screening of sorghum lines for resistance against sugarcane aphid, Melanaphis sacchari (Zehnter)

    USDA-ARS?s Scientific Manuscript database

    The sugarcane aphid Melanaphis sacchari (Zehnter) has emerged as the most significant threat to sorghum (Sorghum bicolor (L.) Moench) production in the United States. Since 2013, discovery of aphid resistant germplasm has been a priority all stakeholders involved. We screened twenty three differen...

  6. Role of Soybean mosaic virus-encoded proteins in seed and aphid transmission in soybean

    USDA-ARS?s Scientific Manuscript database

    Soybean mosaic virus (SMV) is seed and aphid transmitted and can cause significant reductions in yield and seed quality in soybean, Glycine max. The roles in seed and aphid transmission of selected SMV-encoded proteins were investigated by constructing chimeric recombinants between SMV 413 (efficien...

  7. Screening USDA-ARS wheat germplasm for bird cherry-oat aphid tolerance

    USDA-ARS?s Scientific Manuscript database

    The bird cherry-oat aphid (Rhopalosiphum padi L.) can cause significant yield reduction in wheat (Triticum aestivum L.) without causing aboveground visual damage signs or symptoms. This lack of obvious aboveground symptom development makes it difficult to use standard aphid tolerance testing protoc...

  8. Utilization of ladybird beetles to curb aphids in strawberry high tunnels: preliminary results

    USDA-ARS?s Scientific Manuscript database

    Native and exotic aphid species continue to pose a threat to the successful cultivation of small fruits in greenhouses, glasshouses, and high tunnels throughout the World. There is considerable interest in using biological controls (predators and parasitoids) to manage aphids in lieu of synthetic in...

  9. Association mapping of aphid resistance in USDA cowpea (Vigna unguiculata L. Walp.) core collection using SNPs

    USDA-ARS?s Scientific Manuscript database

    Cowpea aphid (CPA; Aphis craccivora) is a destructive insect pest of cowpea, as well as other legume crops including alfalfa, beans, chickpea, lentils, lupins and peanuts. The utilization of aphid resistance in cowpea breeding is one of the most efficient and environmental friendly methods to contro...

  10. Preceding crop affects soybean aphid abundance and predator-prey dynamics in soybean

    USDA-ARS?s Scientific Manuscript database

    Crop rotations alter the soil environment and physiology of the subsequent crop in ways that may affect herbivore abundance. Soybean aphids are a consistent pest of soybean throughout North America, but little work has focused on how preceding crops may affect aphid populations. In a replicated expe...

  11. Status of Imported and Native Predators of the Balsam Woolly Aphid on Mt. Mitchell, North Carolina

    Treesearch

    Gerhard F. Fedde

    1972-01-01

    On the Mt. Mitchell area during the summer of 1968, 20 stands of Fraser fir, Abies fraseri (Pursh) Poir., infested by the balsam woolly aphid, Adelges piceae (Ratzeburg), were examined for native and previously imported predators of the aphid. Laricobius erichsonii Bosenhauer (Coleoptera: Derodontidae) was...

  12. GroEL from the endosymbiont Buchnera aphidicola betrays the aphid by triggering plant defense

    PubMed Central

    Chaudhary, Ritu; Atamian, Hagop S.; Shen, Zhouxin; Briggs, Steven P.; Kaloshian, Isgouhi

    2014-01-01

    Aphids are sap-feeding plant pests and harbor the endosymbiont Buchnera aphidicola, which is essential for their fecundity and survival. During plant penetration and feeding, aphids secrete saliva that contains proteins predicted to alter plant defenses and metabolism. Plants recognize microbe-associated molecular patterns and induce pattern-triggered immunity (PTI). No aphid-associated molecular pattern has yet been identified. By mass spectrometry, we identified in saliva from potato aphids (Macrosiphum euphorbiae) 105 proteins, some of which originated from Buchnera, including the chaperonin GroEL. Because GroEL is a widely conserved bacterial protein with an essential function, we tested its role in PTI. Applying or infiltrating GroEL onto Arabidopsis (Arabidopsis thaliana) leaves induced oxidative burst and expression of PTI early marker genes. These GroEL-induced defense responses required the known coreceptor BRASSINOSTEROID INSENSITIVE 1-ASSOCIATED RECEPTOR KINASE 1. In addition, in transgenic Arabidopsis plants, inducible expression of groEL activated PTI marker gene expression. Moreover, Arabidopsis plants expressing groEL displayed reduced fecundity of the green peach aphid (Myzus persicae), indicating enhanced resistance against aphids. Furthermore, delivery of GroEL into tomato (Solanum lycopersicum) or Arabidopsis through Pseudomonas fluorescens, engineered to express the type III secretion system, also reduced potato aphid and green peach aphid fecundity, respectively. Collectively our data indicate that GroEL is a molecular pattern that triggers PTI. PMID:24927572

  13. Experiences with the sugarcane aphid as a pest of sugarcane in Louisiana

    USDA-ARS?s Scientific Manuscript database

    The sugarcane aphid, Melanaphis sacchari (Zehntner), has been a sporadic but sometimes serious problem on sugarcane in Louisiana since its first discovery in 1999. LSU AgCenter and USDA-ARS scientists have studied aspects of sugarcane aphid management on sugarcane, including pest status, varietal re...

  14. Validation of a hairy roots system to study soybean-soybean aphid interactions

    PubMed Central

    Morriss, Stephanie C.; Studham, Matthew E.; Tylka, Gregory L.

    2017-01-01

    The soybean aphid (Aphis glycines) is one of the main insect pests of soybean (Glycine max) worldwide. Genomics approaches have provided important data on transcriptome changes, both in the insect and in the plant, in response to the plant-aphid interaction. However, the difficulties to transform soybean and to rear soybean aphid on artificial media have hindered our ability to systematically test the function of genes identified by those analyses as mediators of plant resistance to the insect. An efficient approach to produce transgenic soybean material is the production of transformed hairy roots using Agrobacterium rhizogenes; however, soybean aphids colonize leaves or stems and thus this approach has not been utilized. Here, we developed a hairy root system that allowed effective aphid feeding. We show that this system supports aphid performance similar to that observed in leaves. The use of hairy roots to study plant resistance is validated by experiments showing that roots generated from cotyledons of resistant lines carrying the Rag1 or Rag2 resistance genes are also resistant to aphid feeding, while related susceptible lines are not. Our results demonstrate that hairy roots are a good system to study soybean aphid-soybean interactions, providing a quick and effective method that could be used for functional analysis of the resistance response to this insect. PMID:28358854

  15. Geographic distribution of soybean aphid biotypes in USA and Canada during 2008 - 2010

    USDA-ARS?s Scientific Manuscript database

    The soybean aphid (Aphis glycines Matsumura) is a native pest of soybean in eastern Asia and was detected on soybeans in North America in 2000. In 2004, the soybean variety ‘“Dowling”’ was described to be resistant to soybean aphids with the Rag1 gene for resistance. In 2006, a virulent biotype of s...

  16. Evidence for the biochemical basis of host virulence in the greenbug aphid, Schizaphis graminum (Homoptera: Aphididae)

    USDA-ARS?s Scientific Manuscript database

    Biotypes of aphids and many other insect pests are defined based on the phenotypic response of host plants to the insect pest without considering their intrinsic characteristics and genotypes. Plant breeders have spent considerable effort to develop aphid-resistant, small grain varieties to limit in...

  17. Mind your elders: wild soybean’s contribution to soybean aphid resistance

    USDA-ARS?s Scientific Manuscript database

    Currently, biotype 4 soybean aphid (Aphis glycines Matsamura, SBA) is the most virulent SBA biotype. Overcoming the most aphid resistant genes, SBA biotype 4 has become the greatest challenge in utilizing plant resistance in soybean [Glycine max (L.) Merr.]. Soybean’s wild ancestor Glycine soja (Sie...

  18. Sugarcane aphid (Homoptera: Aphididae): A new pest on sorghum in North America

    USDA-ARS?s Scientific Manuscript database

    In 2013 the sugarcane aphid, Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae), a new invasive pest of sorghum in North America, was confirmed on sorghum in four states and 38 counties in the U.S. In 2015, the aphid was reported on sorghum in 17 states and over 400 counties as well as all sorgh...

  19. Inheritance patterns of secondary symbionts during sexual reproduction of pea aphid biotypes.

    PubMed

    Peccoud, Jean; Bonhomme, Joël; Mahéo, Frédérique; de la Huerta, Manon; Cosson, Olivier; Simon, Jean-Christophe

    2014-06-01

    Herbivorous insects frequently harbor bacterial symbionts that affect their ecology and evolution. Aphids host the obligatory endosymbiont Buchnera, which is required for reproduction, together with facultative symbionts whose frequencies vary across aphid populations. These maternally transmitted secondary symbionts have been particularly studied in the pea aphid, Acyrthosiphon pisum, which harbors at least 8 distinct bacterial species (not counting Buchnera) having environmentally dependent effects on host fitness. In particular, these symbiont species are associated with pea aphid populations feeding on specific plants. Although they are maternally inherited, these bacteria are occasionally transferred across insect lineages. One mechanism of such nonmaternal transfer is paternal transmission to the progeny during sexual reproduction. To date, transmission of secondary symbionts during sexual reproduction of aphids has been investigated in only a handful of aphid lineages and 3 symbiont species. To better characterize this process, we investigated inheritance patterns of 7 symbiont species during sexual reproduction of pea aphids through a crossing experiment involving 49 clones belonging to 9 host-specialized biotypes, and 117 crosses. Symbiont species in the progeny were detected with diagnostic qualitative PCR at the fundatrix stage hatching from eggs and in later parthenogenetic generations. We found no confirmed case of paternal transmission of symbionts to the progeny, and we observed that maternal transmission of a particular symbiont species (Serratia symbiotica) was quite inefficient. We discuss these observations in respect to the ecology of the pea aphid.

  20. First report on the entomopathogenic genus Neozygites (Entomophthoromycota) and Neozygites osornensis on aphids in Brazil

    USDA-ARS?s Scientific Manuscript database

    The genus Neozygites has been known in Brazil until now only on mites, and this is its first report on aphids in Brazil. Tree-dwelling aphids (Cinara sp.) on a cypress tree were regularly monitored for entomopathogenic fungi in the city of Terezópolis de Goiás in Central Brazil between July 2014 and...

  1. The Effects of Aphid Traits on Parasitoid Host Use and Specialist Advantage

    PubMed Central

    Gagic, Vesna; Petrović-Obradović, Olivera; Fründ, Jochen; Kavallieratos, Nickolas G.; Athanassiou, Christos G.; Starý, Petr; Tomanović, Željko

    2016-01-01

    Specialization is a central concept in ecology and one of the fundamental properties of parasitoids. Highly specialized parasitoids tend to be more efficient in host-use compared to generalized parasitoids, presumably owing to the trade-off between host range and host-use efficiency. However, it remains unknown how parasitoid host specificity and host-use depends on host traits related to susceptibility to parasitoid attack. To address this question, we used data from a 13-year survey of interactions among 142 aphid and 75 parasitoid species in nine European countries. We found that only aphid traits related to local resource characteristics seem to influence the trade-off between host-range and efficiency: more specialized parasitoids had an apparent advantage (higher abundance on shared hosts) on aphids with sparse colonies, ant-attendance and without concealment, and this was more evident when host relatedness was included in calculation of parasitoid specificity. More traits influenced average assemblage specialization, which was highest in aphids that are monophagous, monoecious, large, highly mobile (easily drop from a plant), without myrmecophily, habitat specialists, inhabit non-agricultural habitats and have sparse colonies. Differences in aphid wax production did not influence parasitoid host specificity and host-use. Our study is the first step in identifying host traits important for aphid parasitoid host specificity and host-use and improves our understanding of bottom-up effects of aphid traits on aphid-parasitoid food web structure. PMID:27309729

  2. Grass hosts of cereal aphids (Hemiptera: Aphididae) between wheat-cropping cycles in South Dakota

    USDA-ARS?s Scientific Manuscript database

    Several grasses may serve as alternative hosts for cereal aphids during the interim between small-grain crops in South Dakota, but field studies to determine which grasses are important have not been undertaken. We sampled annual and perennial grasses for cereal aphids in 18 counties in South Dakot...

  3. Life history and morphological plasticity of three biotypes of soybean aphid (Aphis glycines)

    USDA-ARS?s Scientific Manuscript database

    The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is a pest of soybean, Glycine max (L.) Merr. (Fabaceae), from eastern Asia that was first reported in North America in 2000. The influence of temperature on plasticity of life history and morphological traits of the soybean aphid ha...

  4. Identificatoin and confirmation of resistance against soybean aphid (Aphis glycines) in eight wild soybean lines

    USDA-ARS?s Scientific Manuscript database

    The development and use of aphid-resistant soybean (Glycine max) cultivars has been complicated by the presence of multiple virulent biotypes of the soybean aphid (SA, Aphis glycines Matsumura). Ultimately, a variety of unique resistance sources may be needed to develop cultivars with a broad spectr...

  5. Newly identified resistance to soybean aphid (Aphis glycines) in soybean plant introduction lines

    USDA-ARS?s Scientific Manuscript database

    Host-plant resistance is potentially efficacious in managing the soybean aphid (SA, Aphis glycines Matsumura), a major invasive pest in northern soybean-production regions of North America. However, development of aphid-resistant soybean has been complicated by the presence of virulent SA biotypes,...

  6. Aphid-induced defense responses in Mi-1-mediated compatible and incompatible tomato interactions.

    PubMed

    Martinez de Ilarduya, Oscar; Xie, QiGuang; Kaloshian, Isgouhi

    2003-08-01

    The tomato Mi-1 gene confers resistance to three species of root-knot nematode and potato aphid. We studied changes in expression of jasmonic acid (JA)- and salicylic acid (SA)-dependent defense genes in response to potato and green peach aphids. We determined changes in three PR proteins, lipoxygenase and proteinase inhibitors I and II transcripts, locally and systemically in both compatible and incompatible interactions in tomato. Transcripts for PR-1 were detected earlier and accumulated to higher levels in the incompatible than in the compatible potato aphid/tomato interactions. The transcript profiles of the other genes were similar in compatible compared with incompatible interactions. Pin1 and Pin2 RNAs were detected early and transiently in both compatible and incompatible interactions. In tomato plants containing Mi-1, systemic expression of PR-1 and GluB was detected in both compatible and incompatible interactions at 48 h after infestations with either aphid. These results suggest that aphid feeding involves both SA and JA/ethylene plant defense signaling pathways and that Mi-1-mediated resistance might involve a SA-dependent signaling pathway. Potato aphid feeding generated reactive oxygen species in both compatible and incompatible interactions. However, a hypersensitive response was absent in the Mi-1-mediated resistance response to potato aphids. Reciprocal grafting experiments revealed that resistance is cell autonomous, and local expression of Mi-1 is required for Mi-1-mediated resistance against the potato aphid.

  7. National Plant Diagnostic Network, Taxonomic training videos: Aphids under the microscope - Aphis gossypii

    USDA-ARS?s Scientific Manuscript database

    Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides provides training to identify the cotton aphid, Aphis gossypii, using a compound microscope and an electronic identification key called “LUCID.” The video demonstrates key morphological structures that ca...

  8. National Plant Diagnostic Network, Taxonomic training videos: Aphids under the microscope - Myzus persicae

    USDA-ARS?s Scientific Manuscript database

    Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides provides training to identify the green peach aphid, Myzus persicae, using a compound microscope and an electronic identification key called “LUCID.” The video demonstrates key morphological structures t...

  9. National Plant Diagnostic Network, Taxonomic training videos: Aphids under the microscope - Cerataphis brasiliensis

    USDA-ARS?s Scientific Manuscript database

    Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides provides training to identify the palm aphid, Cerataphis brasiliensis, using a compound microscope and an electronic identification key called “LUCID.” The video demonstrates key morphological structures...

  10. Two Species of Symbiotic Bacteria Present in the Soybean Aphid (Hemiptera: Aphididae)

    USDA-ARS?s Scientific Manuscript database

    Aphids, which feed solely on plant phloem sap, have developed symbiotic associations with bacteria that provide them with the amino acids that are lacking in phloem. Three soybean aphid (Aphis glycines Mat samura) populations were screened for the presence of Buchnera aphidicola and three common spe...

  11. Distribution and diversity of Russian wheat aphid (Homoptera: Aphididae) biotypes in North America

    USDA-ARS?s Scientific Manuscript database

    Wheat with Russian wheat aphid (RWA) resistance based on the Dn4 gene has been important in managing RWA since 1994. Currently, there are eight biotypes (RWA1 - RWA5) of this aphid that have been described based on their ability to differentially damage RWA resistance genes in wheat. RWA2, RWA4, a...

  12. Fitness trade-off in peach-potato aphids (Myzus persicae) between insecticide resistance and vulnerability to parasitoid attack at several spatial scales.

    PubMed

    Foster, S P; Denholm, I; Poppy, G M; Thompson, R; Powell, W

    2011-12-01

    Insecticide-resistant clones of the peach-potato aphid, Myzus persicae (Sulzer), have previously been shown to have a reduced response to aphid alarm pheromone compared to susceptible ones. The resulting vulnerability of susceptible and resistant aphids to attack by the primary endoparasitoid, Diaeretiella rapae (McIntosh), was investigated across three spatial scales. These scales ranged from aphids confined on individual leaves exposed to single female parasitoids, to aphids on groups of whole plants exposed to several parasitoids. In all experiments, significantly fewer aphids from insecticide-susceptible clones became parasitised compared to insecticide-resistant aphids. Investigations of aphid movement showed at the largest spatial scale that more susceptible aphids than resistant aphids moved from their inoculation leaves to other leaves on the same plant after exposure to parasitoids. The findings imply that parasitoids, and possibly other natural enemies, can influence the evolution and dynamics of insecticide resistance through pleiotropic effects of resistance genes on important behavioural traits.

  13. Relationships Between Aphids (Insecta: Homoptera: Aphididae) and Slugs (Gastropoda: Stylommatophora: Agriolimacidae) Pests of Legumes (Fabaceae: Lupinus)

    PubMed Central

    Kozłowski, Jan; Strażyński, Przemysław; Jaskulska, Monika; Kozłowska, Maria

    2016-01-01

    Lupin plants are frequently damaged by various herbivorous invertebrates. Significant among these are slugs and aphids, which sometimes attack the same plants. Relationships between aphids, slugs and food plant are very interesting. Grazing by these pests on young plants can lead to significant yield losses. There is evidence that the alkaloids present in some lupin plants may reduce grazing by slugs, aphids and other invertebrates. In laboratory study was analyzed the relationships between aphid Aphis craccivora and slug Deroceras reticulatum pests of legumes Lupinus angustifolius. It was found that the presence of aphids significantly reduced slug grazing on the plants. The lupin cultivars with high alkaloid content were found to be less heavily damaged by D. reticulatum, and the development of A. craccivora was found to be inhibited on such plants. PMID:27324580

  14. Microorganisms from aphid honeydew attract and enhance the efficacy of natural enemies

    PubMed Central

    Leroy, Pascal D.; Sabri, Ahmed; Heuskin, Stéphanie; Thonart, Philippe; Lognay, Georges; Verheggen, François J.; Francis, Frédéric; Brostaux, Yves; Felton, Gary W.; Haubruge, Eric

    2011-01-01

    Aphids are one of the most serious pests of crops worldwide, causing major yield and economic losses. To control aphids, natural enemies could be an option but their efficacy is sometimes limited by their dispersal in natural environment. Here we report the first isolation of a bacterium from the pea aphid Acyrthosiphon pisum honeydew, Staphylococcus sciuri, which acts as a kairomone enhancing the efficiency of aphid natural enemies. Our findings represent the first case of a host-associated bacterium driving prey location and ovipositional preference for the natural enemy. We show that this bacterium has a key role in tritrophic interactions because it is the direct source of volatiles used to locate prey. Some specific semiochemicals produced by S. sciuri were also identified as significant attractants and ovipositional stimulants. The use of this host-associated bacterium could certainly provide a novel approach to control aphids in field and greenhouse systems. PMID:21673669

  15. Spectral Detection of Soybean Aphid (Hemiptera: Aphididae) and Confounding Insecticide Effects in Soybean

    NASA Astrophysics Data System (ADS)

    Alves, Tavvs Micael

    Soybean aphid, Aphis glycines (Hemiptera: Aphididae) is the primary insect pest of soybean in the northcentral United States. Soybean aphid may cause stunted plants, leaf discoloration, plant death, and decrease soybean yield by 40%. Sampling plans have been developed for supporting soybean aphid management. However, growers' perception about time involved in direct insect counts has been contributing to a lower adoption of traditional pest scouting methods and may be associated with the use of prophylactic insecticide applications in soybean. Remote sensing of plant spectral (light-derived) responses to soybean aphid feeding is a promising alternative to estimate injury without direct insect counts and, thus, increase adoption and efficiency of scouting programs. This research explored the use of remote sensing of soybean reflectance for detection of soybean aphids and showed that foliar insecticides may have implications for subsequent use of soybean spectral reflectance for pest detection. (Abstract shortened by ProQuest.).

  16. Prevalence of entomophthoralean fungi (Entomophthoromycota) of aphids in relation to developmental stages.

    PubMed

    Manfrino, Romina G; Gutierrez, Alejandra C; Rueda Páramo, Manuel E; Salto, César E; López Lastra, Claudia C

    2016-08-01

    Transmission of fungal pathogens of aphids may be affected by the host developmental stage. Brassica and Lactuca sativa L. crops were sampled in Santa Fe, Argentina, to determine the prevalence of fungal-diseased aphids and investigate the differences between developmental stages of aphids. The fungal pathogens identified were Zoophthora radicans (Bref.) A. Batko, Pandora neoaphidis (Remaud. & Hennebert) Humber and Entomophthora planchoniana Cornu. Their prevalence on each crop was calculated. The numbers of infected aphids were significantly different between the different developmental stages on all crops except B. oleracea var. botrytis L. The entomophthoralean fungi identified are important mortality factors of aphids on horticultural crops in Santa Fe. The numbers of infected nymphs and adults were significantly different, nymphs being the most affected developmental stage. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  17. Parasitoids and hyperparasitoids (Hymenoptera) on aphids (Hemiptera) infesting citrus in east Mediterranean region of Turkey.

    PubMed

    Satar, Serdar; Satar, Gül; Karacaoğlu, Mehmet; Uygun, Nedim; Kavallieratos, Nickolas G; Starý, Petr; Athanassiou, Christos G

    2014-01-01

    The aphids, aphid parasitoids, and hyperparasitoids found in citrus orchards, the parasitoids' and hyperparasitoids' seasonal abundance, and the plant-aphid-parasitoid relationships in Hatay, Osmaniye, Adana, and Mersin provinces of the east Mediterranean region of Turkey are presented in the present 2-yr study. Aphidius colemani Viereck, Binodoxys angelicae (Haliday), and Lysiphlebus confusus Tremblay and Eady (Hymenoptera: Braconidae: Aphidiinae) were encountered as the most common parasitoids among 10 identified aphidiine and aphelinid taxa on different citrus species. Hyperparasitoids belonging to the genera Alloxysta, Phaenoglyphis, Asaphes, Pachyneuron, Syrphophagus, and Dendrocerus are reported for the first time emerging from aphids feeding on citrus in Turkey. Among them, Asaphes spp., Pachyneuron spp., and Syrphophagus spp. were recorded as the most common ones. Citrus reticulata Blanco and Citrus limon (L.) Burm. fil. were recorded as main hosts for the aphid parasitoids and their hyperparasitoids. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

  18. Relationships Between Aphids (Insecta: Homoptera: Aphididae) and Slugs (Gastropoda: Stylommatophora: Agriolimacidae) Pests of Legumes (Fabaceae: Lupinus).

    PubMed

    Kozłowski, Jan; Strażyński, Przemysław; Jaskulska, Monika; Kozłowska, Maria

    2016-01-01

    Lupin plants are frequently damaged by various herbivorous invertebrates. Significant among these are slugs and aphids, which sometimes attack the same plants. Relationships between aphids, slugs and food plant are very interesting. Grazing by these pests on young plants can lead to significant yield losses. There is evidence that the alkaloids present in some lupin plants may reduce grazing by slugs, aphids and other invertebrates. In laboratory study was analyzed the relationships between aphid Aphis craccivora and slug Deroceras reticulatum pests of legumes Lupinus angustifolius. It was found that the presence of aphids significantly reduced slug grazing on the plants. The lupin cultivars with high alkaloid content were found to be less heavily damaged by D. reticulatum, and the development of A. craccivora was found to be inhibited on such plants.

  19. Reliable screening technique for evaluation of wild crucifers against mustard aphid Lipaphis erysimi (Kalt.).

    PubMed

    Singh, S P; Kumar, Sandeep; Singh, Y P; Singh, Ram

    2014-12-01

    Wild crucifers namely Arabidopsis thaliana, Brassica fruticulosa, B. rugosa, B. spinescens, B. tournefortii, Camelina sativa, Capsella bursa-pastoris, Crambe abysinnica, Cronopus didymus, Diplotaxis assurgens, D. gomez-campoi, D. muralis, D. siettiana, D. tenuisiliqua, Enatharocarpus lyratus, Lepidium sativum and Sinapis alba along with five cultivated Brassica species including B. rapa (BSH-1), B. juncea (Rohini), B. napus (GSC-6), B. carinata (DLSC-2) and Eruca sativa (T-27) were screened against mustard aphid Lipaphis erysimi (Kalt.) with a standardized technique under definite level of aphid pressure developed using specially designed cages. Observations have revealed that B. fruticulosa, B. spinescens, Camelina sativa, Crambe abysinnica and Lepidium sativum were resistant to mustard aphid L. erysimi with aphid infestation index (AII) ≤ 1. Capsella bursa-pastoris was highly susceptible to bean aphid, Aphis fabae during its vegetative stage (with 100% mortality). Other genotypes were found in the range of 'susceptible' to 'highly susceptible' with AII ranging 3-5.

  20. Effect of plant nutrition on aphid size, prey consumption, and life history characteristics of green lacewing.

    PubMed

    Aqueel, Muhammad A; Collins, Catherine M; Raza, Abu-bakar M; Ahmad, Shahbaz; Tariq, Muhammad; Leather, Simon R

    2014-02-01

    Plant quality can directly and indirectly affect the third trophic level. The predation by all the instars of green lacewing, Chrysoperla carnea (S.) (Neuroptera: Chrysopidae) on the cereal aphids, Rhopalosiphum padi (L.), and Sitobion avenae (F.) at varying nitrogen fertilizer levels was calculated under laboratory conditions. Wheat plants were grown on four nitrogen fertilizer levels and aphids were fed on these plants and subsequently offered as food to the C. carnea. Aphid densities of 10, 30, and 90 were offered to first, second, and third instar larvae of green lacewing. Increased nitrogen application improved nitrogen contents of the plants and also the body weight of cereal aphids feeding on them. Aphid consumption by green lacewings was reduced with the increase in nitrogen content in the host plants of aphids. Predation of both aphid species by first, second, and third instars larvae of C. carnea was highest on aphids reared on plants with the lowest rate of fertilization, suggesting a compensatory consumption to overcome reduced biomass (lower aphid size). Total biomass devoured by C. carnea on all nitrogen fertilizer treatments was not statistically different. Additionally, the heavier host prey influenced by the plant nutrition had an effect on the life history characteristics of green lacewings. The larval duration, pupal weight, pupal duration, fecundity, and male and female longevity were significantly affected by the level of nitrogen fertilization to the aphid's host plants, except for pupal duration when fed on S. avenae. This study showed that quantity of prey supplied to the larvae affects the prey consumption and thereafter the life history characteristics of green lacewings. © 2013 Institute of Zoology, Chinese Academy of Sciences.

  1. Coil-dependent signaling pathway is not required for Mi-1-mediated potato aphid resistance.

    PubMed

    Bhattarai, Kishor K; Xie, Qi-Guang; Pourshalimi, Daniel; Younglove, Ted; Kaloshian, Isgouhi

    2007-03-01

    Tomato (Solanum lycopersicum) has a unique resistance gene, Mi-1, that confers resistance to animals from distinct taxa, nematodes, and piercing and sucking insects. Mi-1 encodes a protein with a nucleotide-binding site and leucine-rich repeat motifs. Early in the potato aphid (Macrosiphum euphorbiae)--tomato interactions, aphid feeding induces the expression of the jasmonic acid (JA)-regulated proteinase inhibitor genes, Pin1 and Pin2. The jail-1 (jasmonic acid insensitive 1) tomato mutant, which is impaired in JA perception, was used to gain additional insight into the JA signaling pathway and its role in the Mi-1-mediated aphid resistance. The jail-1 mutant has a deletion in the Coil gene that encodes a putative F-box protein. In this study, aphid colonization, survival, and fecundity were compared on wild-type tomato and jail-1 mutant. In choice assays, the jail-1 mutant showed higher colonization by potato aphids compared with wild-type tomato. In contrast, no-choice assays showed no difference in potato aphid survival or fecundity between jail-1 and the wild-type parent. Plants homozygous for Mi-1 and for the jail mutation were not compromised in resistance to potato aphids, using either choice or no-choice assays. In addition, the accumulation of JA-regulated Pin1 transcripts after aphid feeding was Coil dependent. Taken together, these data indicate that, although potato aphids activate Coil-dependent defense response in tomato, this response is not required for Mi-1-mediated resistance to aphids.

  2. Enhanced aphid abundance in spring desynchronizes predator-prey and plant-microorganism interactions.

    PubMed

    Fuchs, Benjamin; Breuer, Tatjana; Findling, Simone; Krischke, Markus; Mueller, Martin J; Holzschuh, Andrea; Krauss, Jochen

    2017-02-01

    Climate change leads to phenology shifts of many species. However, not all species shift in parallel, which can desynchronize interspecific interactions. Within trophic cascades, herbivores can be top-down controlled by predators or bottom-up controlled by host plant quality and host symbionts, such as plant-associated micro-organisms. Synchronization of trophic levels is required to prevent insect herbivore (pest) outbreaks. In a common garden experiment, we simulated an earlier arrival time (~2 weeks) of the aphid Rhopalosiphum padi on its host grass Lolium perenne by enhancing the aphid abundance during the colonization period. L. perenne was either uninfected or infected with the endophytic fungus Epichloë festucae var. lolii. The plant symbiotic fungus produces insect deterring alkaloids within the host grass. Throughout the season, we tested the effects of enhanced aphid abundance in spring on aphid predators (top-down) and grass-endophyte (bottom-up) responses. Higher aphid population sizes earlier in the season lead to overall higher aphid abundances, as predator occurrence was independent of aphid abundances on the pots. Nonetheless, after predator occurrence, aphids were controlled within 2 weeks on all pots. Possible bottom-up control of aphids by increased endophyte concentrations occurred time delayed after high herbivore abundances. Endophyte-derived alkaloid concentrations were not significantly affected by enhanced aphid abundance but increased throughout the season. We conclude that phenology shifts in an herbivorous species can desynchronize predator-prey and plant-microorganism interactions and might enhance the probability of pest outbreaks with climate change.

  3. Overexpression of IRM1 enhances resistance to aphids in Arabidopsis thaliana.

    PubMed

    Chen, Xi; Zhang, Zhao; Visser, Richard G F; Broekgaarden, Colette; Vosman, Ben

    2013-01-01

    Aphids are insects that cause direct damage to crops by the removal of phloem sap, but more importantly they spread devastating viruses. Aphids use their sophisticated mouthpart (i.e. stylet) to feed from the phloem sieve elements of the host plant. To identify genes that affect host plant resistance to aphids, we previously screened an Arabidopsis thaliana activation tag mutant collection. In such mutants, tagged genes are overexpressed by a strong 35S enhancer adjacent to the natural promoter, resulting in a dominant gain-of-function phenotype. We previously identified several of these mutants on which the aphid Myzus persicae showed a reduced population development compared with wild type. In the present study we show that the gene responsible for the phenotype of one of the mutants is At5g65040 and named this gene Increased Resistance to Myzus persicae 1 (IRM1). Overexpression of the cloned IRM1 gene conferred a phenotype identical to that of the original mutant. Conversely, an IRM1 knockout mutant promoted aphid population development compared to the wild type. We performed Electrical Penetration Graph analysis to investigate how probing and feeding behaviour of aphids was affected on plants that either overexpressed IRM1 or contained a knockout mutation in this gene. The EPG results indicated that the aphids encounter resistance factors while reaching for the phloem on the overexpressing line. This resistance mechanism also affected other aphid species and is suggested to be of mechanical nature. Interestingly, genetic variation for IRM1 expression in response to aphid attack was observed. Upon aphid attack the expression of IRM1 was initially (after 6 hours) induced in ecotype Wassilewskija followed by suppression. In Columbia-0, IRM1 expression was already suppressed six hours after the start of the infestation. The resistance conferred by the overexpression of IRM1 in A. thaliana trades off with plant growth.

  4. Silencing of aphid genes by dsRNA feeding from plants.

    PubMed

    Pitino, Marco; Coleman, Alexander D; Maffei, Massimo E; Ridout, Christopher J; Hogenhout, Saskia A

    2011-01-01

    RNA interference (RNAi) is a valuable reverse genetics tool to study gene function in various organisms, including hemipteran insects such as aphids. Previous work has shown that RNAi-mediated knockdown of pea aphid (Acyrthosiphon pisum) genes can be achieved through direct injection of double-stranded RNA (dsRNA) or small-interfering RNAs (siRNA) into the pea aphid hemolymph or by feeding these insects on artificial diets containing the small RNAs. In this study, we have developed the plant-mediated RNAi technology for aphids to allow for gene silencing in the aphid natural environment and minimize handling of these insects during experiments. The green peach aphid M. persicae was selected because it has a broad plant host range that includes the model plants Nicotiana benthamiana and Arabidopsis thaliana for which transgenic materials can relatively quickly be generated. We targeted M. persicae Rack1, which is predominantly expressed in the gut, and M. persicae C002 (MpC002), which is predominantly expressed in the salivary glands. The aphids were fed on N. benthamiana leaf disks transiently producing dsRNA corresponding to these genes and on A. thaliana plants stably producing the dsRNAs. MpC002 and Rack-1 expression were knocked down by up to 60% on transgenic N. benthamiana and A. thaliana. Moreover, silenced M. persicae produced less progeny consistent with these genes having essential functions. Similar levels of gene silencing were achieved in our plant-mediated RNAi approach and published silencing methods for aphids. Furthermore, the N. benthamiana leaf disk assay can be developed into a screen to assess which genes are essential for aphid survival on plants. Our results also demonstrate the feasibility of the plant-mediated RNAi approach for aphid control.

  5. Methyl salicylate attracts natural enemies and reduces populations of soybean aphids (Hemiptera: Aphididae) in soybean agroecosystems.

    PubMed

    Mallinger, Rachel E; Hogg, David B; Gratton, Claudio

    2011-02-01

    Methyl salicylate, an herbivore-induced plant volatile, has been shown to attract natural enemies and affect herbivore behavior. In this study, methyl salicylate was examined for its attractiveness to natural enemies of the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), and for its direct effects on soybean aphid population growth rates. Methyl salicylate lures were deployed in plots within organic soybean [Glycine max (L.) Merr.] fields. Sticky card traps adjacent to and 1.5 m from the lure measured the relative abundance of natural enemies, and soybean aphid populations were monitored within treated and untreated plots. In addition, exclusion cage studies were conducted to determine methyl salicylate's effect on soybean aphid population growth rates in the absence of natural enemies. Significantly greater numbers of syrphid flies (Diptera: Syrphidae) and green lacewings (Neuroptera: Chrysopidae) were caught on traps adjacent to the methyl salicylate lure, but no differences in abundance were found at traps 1.5 m from the lure. Furthermore, abundance of soybean aphids was significantly lower in methyl salicylate-treated plots. In exclusion cage studies, soybean aphid numbers were significantly reduced on treated soybean plants when all plants were open to natural enemies. When plants were caged, however, soybean aphid numbers and population growth rates did not differ between treated and untreated plants suggesting no effect of methyl salicylate on soybean aphid reproduction and implicating the role of natural enemies in depressing aphid populations. Although aphid populations were reduced locally around methyl salicylate lures, larger scale studies are needed to assess the technology at the whole-field scale.

  6. The green lacewing, Chrysoperla carnea: preference between lettuce aphids, Nasonovia ribisnigri, and Western flower thrips, Frankliniella occidentalis.

    PubMed

    Shrestha, Govinda; Enkegaard, Annie

    2013-01-01

    This study investigated the prey preference of 3(rd) instar green lacewing, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae), between western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), and lettuce aphids, Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae) in laboratory experiments at 25 ± 1° C and 70 ± 5% RH with five prey ratios (10 aphids:80 thrips, 25 aphids:65 thrips, 45 aphids:45 thrips, 65 aphids:25 thrips, and 80 aphids:10 thrips). Third instar C. carnea larvae readily preyed upon both thrips and aphids, with thrips mortality varying between 40 and 90%, and aphid mortality between 52 and 98%. Chrysoperla carnea had a significant preference for N. ribisnigri at two ratios (10 aphids:80 thrips, 65 aphids:25 thrips), but no preference for either prey at the other ratios. There was no significant linear relationship between preference index and prey ratio, but a significant intercept of the linear regression indicated an overall preference of C. carnea for aphids with a value of 0.651 ± 0.054. The possible implications of these findings for control of N. ribisnigri and F. occidentalis by C. carnea are discussed.

  7. The Green Lacewing, Chrysoperla carnea: Preference between Lettuce Aphids, Nasonovia ribisnigri, and Western Flower Thrips, Frankliniella occidentalis

    PubMed Central

    Shrestha, Govinda; Enkegaard, Annie

    2013-01-01

    This study investigated the prey preference of 3rd instar green lacewing, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae), between western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), and lettuce aphids, Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae) in laboratory experiments at 25 ± 1° C and 70 ± 5% RH with five prey ratios (10 aphids:80 thrips, 25 aphids:65 thrips, 45 aphids:45 thrips, 65 aphids:25 thrips, and 80 aphids:10 thrips). Third instar C. carnea larvae readily preyed upon both thrips and aphids, with thrips mortality varying between 40 and 90%, and aphid mortality between 52 and 98%. Chrysoperla carnea had a significant preference for N. ribisnigri at two ratios (10 aphids:80 thrips, 65 aphids:25 thrips), but no preference for either prey at the other ratios. There was no significant linear relationship between preference index and prey ratio, but a significant intercept of the linear regression indicated an overall preference of C. carnea for aphids with a value of 0.651 ± 0.054. The possible implications of these findings for control of N. ribisnigri and F. occidentalis by C. carnea are discussed. PMID:24205864

  8. Survey of aphid population in a yellow passion fruit crop and its relationship on the spread Cowpea aphid-borne mosaic virus in a subtropical region of Brazil.

    PubMed

    Garcêz, Renata Maia; Chaves, Alexandre Levi Rodrigues; Eiras, Marcelo; Meletti, Laura Maria Molina; de Azevedo Filho, Joaquim Adelino; da Silva, Leonardo Assis; Colariccio, Addolorata

    2015-01-01

    Passion fruit woodiness may be caused by Cowpea aphid-borne mosaic virus (CABMV) and is currently the major passion fruit disease in Brazil. To assess the virus-vector-host interactions, a newly introduced golden passion fruit plantation located in eastern region of São Paulo State, Brazil, was monitored. Dissemination of CABMV was determined analyzing golden passion fruit plants monthly for 18 months by PTA-ELISA. Seasonality and aphid fauna diversity was determined by identification of the captured species using yellow sticky, yellow water-pan and green tile traps. Population composition of the aphid species was determined using the descriptive index of occurrence, dominance and general classification and overlap of species in the R program. Analyses of species grouping afforded to recognize 14 aphid species. The genus Aphis represented 55.42 % of the species captured. Aphid species formed two distinct clusters, one of which was characterized by the diversity of polyphagous species that presented high potential to spread CABMV. The low abundance and diversity of aphid species did not interfere negatively in the CABMV epidemiology. The genus Aphis, particularly Aphis fabae/solanella and A. gossypii, was crucial in the spread of CABMV in passion fruit orchards in the eastern State of São Paulo.

  9. A trio of viral proteins tunes aphid-plant interactions in Arabidopsis thaliana.

    PubMed

    Westwood, Jack H; Groen, Simon C; Du, Zhiyou; Murphy, Alex M; Anggoro, Damar Tri; Tungadi, Trisna; Luang-In, Vijitra; Lewsey, Mathew G; Rossiter, John T; Powell, Glen; Smith, Alison G; Carr, John P

    2013-01-01

    Virus-induced deterrence to aphid feeding is believed to promote plant virus transmission by encouraging migration of virus-bearing insects away from infected plants. We investigated the effects of infection by an aphid-transmitted virus, cucumber mosaic virus (CMV), on the interaction of Arabidopsis thaliana, one of the natural hosts for CMV, with Myzus persicae (common names: 'peach-potato aphid', 'green peach aphid'). Infection of Arabidopsis (ecotype Col-0) with CMV strain Fny (Fny-CMV) induced biosynthesis of the aphid feeding-deterrent 4-methoxy-indol-3-yl-methylglucosinolate (4MI3M). 4MI3M inhibited phloem ingestion by aphids and consequently discouraged aphid settling. The CMV 2b protein is a suppressor of antiviral RNA silencing, which has previously been implicated in altering plant-aphid interactions. Its presence in infected hosts enhances the accumulation of CMV and the other four viral proteins. Another viral gene product, the 2a protein (an RNA-dependent RNA polymerase), triggers defensive signaling, leading to increased 4MI3M accumulation. The 2b protein can inhibit ARGONAUTE1 (AGO1), a host factor that both positively-regulates 4MI3M biosynthesis and negatively-regulates accumulation of substance(s) toxic to aphids. However, the 1a replicase protein moderated 2b-mediated inhibition of AGO1, ensuring that aphids were deterred from feeding but not poisoned. The LS strain of CMV did not induce feeding deterrence in Arabidopsis ecotype Col-0. Inhibition of AGO1 by the 2b protein could act as a booby trap since this will trigger antibiosis against aphids. However, for Fny-CMV the interplay of three viral proteins (1a, 2a and 2b) appears to balance the need of the virus to inhibit antiviral silencing, while inducing a mild resistance (antixenosis) that is thought to promote transmission. The strain-specific effects of CMV on Arabidopsis-aphid interactions, and differences between the effects of Fny-CMV on this plant and those seen previously in tobacco

  10. EMS mutagenesis in the pea aphid Acyrthosiphon pisum.

    PubMed

    Tagu, Denis; Le Trionnaire, Gaël; Tanguy, Sylvie; Gauthier, Jean-Pierre; Huynh, Jean-René

    2014-04-16

    In aphids, clonal individuals can show distinct morphologic traits in response to environmental cues. Such phenotypic plasticity cannot be studied with classical genetic model organisms such as Caenorhabditis elegans or Drosophila melanogaster. The genetic basis of this biological process remain unknown, as mutations affecting this process are not available in aphids. Here, we describe a protocol to treat third-stage larvae with an alkylating mutagen, ethyl methanesulfonate (EMS), to generate random mutations within the Acyrthosiphon pisum genome. We found that even low concentrations of EMS were toxic for two genotypes of A. pisum. Mutagenesis efficiency was nevertheless assessed by estimating the occurrence of mutational events on the X chromosome. Indeed, any lethal mutation on the X-chromosome would kill males that are haploid on the X so that we used the proportion of males as an estimation of mutagenesis efficacy. We could assess a putative mutation rate of 0.4 per X-chromosome at 10 mM of EMS. We then applied this protocol to perform a small-scale mutagenesis on parthenogenetic individuals, which were screened for defects in their ability to produce sexual individuals in response to photoperiod shortening. We found one mutant line showing a reproducible altered photoperiodic response with a reduced production of males and the appearance of aberrant winged males (wing atrophy, alteration of legs morphology). This mutation appeared to be stable because it could be transmitted over several generations of parthenogenetic individuals. To our knowledge, this study represents the first example of an EMS-generated aphid mutant.

  11. EMS Mutagenesis in the Pea Aphid Acyrthosiphon pisum

    PubMed Central

    Tagu, Denis; Le Trionnaire, Gaël; Tanguy, Sylvie; Gauthier, Jean-Pierre; Huynh, Jean-René

    2014-01-01

    In aphids, clonal individuals can show distinct morphologic traits in response to environmental cues. Such phenotypic plasticity cannot be studied with classical genetic model organisms such as Caenorhabditis elegans or Drosophila melanogaster. The genetic basis of this biological process remain unknown, as mutations affecting this process are not available in aphids. Here, we describe a protocol to treat third-stage larvae with an alkylating mutagen, ethyl methanesulfonate (EMS), to generate random mutations within the Acyrthosiphon pisum genome. We found that even low concentrations of EMS were toxic for two genotypes of A. pisum. Mutagenesis efficiency was nevertheless assessed by estimating the occurrence of mutational events on the X chromosome. Indeed, any lethal mutation on the X-chromosome would kill males that are haploid on the X so that we used the proportion of males as an estimation of mutagenesis efficacy. We could assess a putative mutation rate of 0.4 per X-chromosome at 10 mM of EMS. We then applied this protocol to perform a small-scale mutagenesis on parthenogenetic individuals, which were screened for defects in their ability to produce sexual individuals in response to photoperiod shortening. We found one mutant line showing a reproducible altered photoperiodic response with a reduced production of males and the appearance of aberrant winged males (wing atrophy, alteration of legs morphology). This mutation appeared to be stable because it could be transmitted over several generations of parthenogenetic individuals. To our knowledge, this study represents the first example of an EMS-generated aphid mutant. PMID:24531730

  12. 30 CFR 250.510 - Diesel engine air intakes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false Diesel engine air intakes. 250.510 Section 250... Operations § 250.510 Diesel engine air intakes. Diesel engine air intakes must be equipped with a device to shut down the diesel engine in the event of runaway. Diesel engines that are continuously attended...

  13. 30 CFR 250.610 - Diesel engine air intakes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false Diesel engine air intakes. 250.610 Section 250... Operations § 250.610 Diesel engine air intakes. No later than May 31, 1989, diesel engine air intakes shall be equipped with a device to shut down the diesel engine in the event of runaway. Diesel...

  14. 30 CFR 250.610 - Diesel engine air intakes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false Diesel engine air intakes. 250.610 Section 250... Operations § 250.610 Diesel engine air intakes. No later than May 31, 1989, diesel engine air intakes shall be equipped with a device to shut down the diesel engine in the event of runaway. Diesel...

  15. 30 CFR 250.510 - Diesel engine air intakes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false Diesel engine air intakes. 250.510 Section 250... Operations § 250.510 Diesel engine air intakes. Diesel engine air intakes must be equipped with a device to shut down the diesel engine in the event of runaway. Diesel engines that are continuously attended...

  16. 30 CFR 250.510 - Diesel engine air intakes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false Diesel engine air intakes. 250.510 Section 250... Well-Completion Operations § 250.510 Diesel engine air intakes. Diesel engine air intakes must be equipped with a device to shut down the diesel engine in the event of runaway. Diesel engines that are...

  17. 30 CFR 250.610 - Diesel engine air intakes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Diesel engine air intakes. 250.610 Section 250... engine air intakes. No later than May 31, 1989, diesel engine air intakes shall be equipped with a device to shut down the diesel engine in the event of runaway. Diesel engines which are continuously...

  18. 30 CFR 250.510 - Diesel engine air intakes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Diesel engine air intakes. 250.510 Section 250... engine air intakes. Diesel engine air intakes must be equipped with a device to shut down the diesel engine in the event of runaway. Diesel engines that are continuously attended must be equipped with...

  19. 30 CFR 250.610 - Diesel engine air intakes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false Diesel engine air intakes. 250.610 Section 250... Well-Workover Operations § 250.610 Diesel engine air intakes. No later than May 31, 1989, diesel engine air intakes shall be equipped with a device to shut down the diesel engine in the event of runaway...

  20. 30 CFR 250.510 - Diesel engine air intakes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 2 2013-07-01 2013-07-01 false Diesel engine air intakes. 250.510 Section 250.510 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR... Operations § 250.510 Diesel engine air intakes. Diesel engine air intakes must be equipped with a device...

  1. Differential Expression of Superoxide Dismutase Genes in Aphid-Stressed Maize (Zea mays L.) Seedlings

    PubMed Central

    Sytykiewicz, Hubert

    2014-01-01

    The aim of this study was to compare the expression patterns of superoxide dismutase genes (sod2, sod3.4, sod9 and sodB) in seedling leaves of the Zea mays L. Tasty Sweet (susceptible) and Ambrozja (relatively resistant) cultivars infested with one of two hemipteran species, namely monophagous Sitobion avenae F. (grain aphid) or oligophagous Rhopalosiphum padi L. (bird cherry-oat aphid). Secondarily, aphid-elicited alternations in the antioxidative capacity towards DPPH (1,1-diphenyl-2-picrylhydrazyl) radical in insect-stressed plants were evaluated. Comprehensive comparison of expression profiles of the four sod genes showed that both insect species evoked significant upregulation of three genes sod2, sod3.4 and sod9). However, aphid infestation affected non-significant fluctuations in expression of sodB gene in seedlings of both maize genotypes. The highest levels of transcript accumulation occurred at 8 h (sod2 and sod3.4) or 24 h (sod9) post-infestation, and aphid-induced changes in the expression of sod genes were more dramatic in the Ambrozja cultivar than in the Tasty Sweet variety. Furthermore, bird cherry-oat aphid colonization had a more substantial impact on levels of DPPH radical scavenging activity in infested host seedlings than grain aphid colonization. Additionally, Ambrozja plants infested by either hemipteran species showed markedly lower antioxidative capacity compared with attacked Tasty Sweet plants. PMID:24722734

  2. AtWRKY22 promotes susceptibility to aphids and modulates salicylic acid and jasmonic acid signalling

    PubMed Central

    Kloth, Karen J.; Wiegers, Gerrie L.; Busscher-Lange, Jacqueline; van Haarst, Jan C.; Kruijer, Willem; Bouwmeester, Harro J.; Dicke, Marcel; Jongsma, Maarten A.

    2016-01-01

    Aphids induce many transcriptional perturbations in their host plants, but the signalling cascades responsible and the effects on plant resistance are largely unknown. Through a genome-wide association (GWA) mapping study in Arabidopsis thaliana, we identified WRKY22 as a candidate gene associated with feeding behaviour of the green peach aphid, Myzus persicae. The transcription factor WRKY22 is known to be involved in pathogen-triggered immunity, and WRKY22 gene expression has been shown to be induced by aphids. Assessment of aphid population development and feeding behaviour on knockout mutants and overexpression lines showed that WRKY22 increases susceptibility to M. persicae via a mesophyll-located mechanism. mRNA sequencing analysis of aphid-infested wrky22 knockout plants revealed the up-regulation of genes involved in salicylic acid (SA) signalling and down-regulation of genes involved in plant growth and cell-wall loosening. In addition, mechanostimulation of knockout plants by clip cages up-regulated jasmonic acid (JA)-responsive genes, resulting in substantial negative JA–SA crosstalk. Based on this and previous studies, WRKY22 is considered to modulate the interplay between the SA and JA pathways in response to a wide range of biotic and abiotic stimuli. Its induction by aphids and its role in suppressing SA and JA signalling make WRKY22 a potential target for aphids to manipulate host plant defences. PMID:27107291

  3. Development of a DNA microarray for species identification of quarantine aphids.

    PubMed

    Lee, Won Sun; Choi, Hwalran; Kang, Jinseok; Kim, Ji-Hoon; Lee, Si Hyeock; Lee, Seunghwan; Hwang, Seung Yong

    2013-12-01

    Aphid pests are being brought into Korea as a result of increased crop trading. Aphids exist on growth areas of plants, and thus plant growth is seriously affected by aphid pests. However, aphids are very small and have several sexual morphs and life stages, so it is difficult to identify species on the basis of morphological features. This problem was approached using DNA microarray technology. DNA targets of the cytochrome c oxidase subunit I gene were generated with a fluorescent dye-labelled primer and were hybridised onto a DNA microarray consisting of specific probes. After analysing the signal intensity of the specific probes, the unique patterns from the DNA microarray, consisting of 47 species-specific probes, were obtained to identify 23 aphid species. To confirm the accuracy of the developed DNA microarray, ten individual blind samples were used in blind trials, and the identifications were completely consistent with the sequencing data of all individual blind samples. A microarray has been developed to distinguish aphid species. DNA microarray technology provides a rapid, easy, cost-effective and accurate method for identifying aphid species for pest control management. © 2013 Society of Chemical Industry.

  4. Indirect Effect of a Transgenic Wheat on Aphids through Enhanced Powdery Mildew Resistance

    PubMed Central

    von Burg, Simone; Álvarez-Alfageme, Fernando; Romeis, Jörg

    2012-01-01

    In agricultural ecosystems, arthropod herbivores and fungal pathogens are likely to colonise the same plant and may therefore affect each other directly or indirectly. The fungus that causes powdery mildew (Blumeria graminis tritici) and cereal aphids are important pests of wheat but interactions between them have seldom been investigated. We studied the effects of powdery mildew of wheat on two cereal aphid species, Metopolophium dirhodum and Rhopalosiphum padi. We hypothesized that aphid number and size will be smaller on powdery mildew-infected plants than on non-infected plants. In a first experiment we used six commercially available wheat varieties whereas in the second experiment we used a genetically modified (GM) mildew-resistant wheat line and its non-transgenic sister line. Because the two lines differed only in the presence of the transgene and in powdery mildew resistance, experiment 2 avoided the confounding effect of variety. In both experiments, the number of M. dirhodum but not of R. padi was reduced by powdery mildew infection. Transgenic mildew-resistant lines therefore harboured bigger aphid populations than the non-transgenic lines. For both aphid species individual size was mostly influenced by aphid number. Our results indicate that plants that are protected from a particular pest (powdery mildew) became more favourable for another pest (aphids). PMID:23056284

  5. Plant genotype shapes ant-aphid interactions: implications for community structure and indirect plant defense.

    PubMed

    Mooney, Kailen A; Agrawal, Anurag A

    2008-06-01

    Little is known about the mechanisms by which plant genotype shapes arthropod community structure. In a field experiment, we measured the effects of milkweed (Asclepias syriaca) genotype and ants on milkweed arthropods. Populations of the ant-tended aphid Aphis asclepiadis and the untended aphid Myzocallis asclepiadis varied eight- to 18-fold among milkweed genotypes, depending on aphid species and whether ants were present. There was no milkweed effect on predatory arthropods. Ants increased Aphis abundance 59%, decreased Myzocallis abundance 52%, and decreased predator abundance 56%. Milkweed genotype indirectly influenced ants via direct effects on Aphis and Myzocallis abundance. Milkweed genotype also modified ant-aphid interactions, influencing the number of ants attracted per Aphis and Myzocallis. While ant effects on Myzocallis were consistently negative, effects on Aphis ranged from antagonistic to mutualistic among milkweed genotypes. As a consequence of milkweed effects on ant-aphid interactions, ant abundance varied 13-fold among milkweed genotypes, and monarch caterpillar survival was negatively correlated with genetic variation in ant abundance. We speculate that heritable variation in milkweed phloem sap drives these effects on aphids, ants, and caterpillars. In summary, milkweed exerts genetic control over the interactions between aphids and an ant that provides defense against foliage-feeding caterpillars.

  6. The structural sheath protein of aphids is required for phloem feeding.

    PubMed

    Will, Torsten; Vilcinskas, Andreas

    2015-02-01

    Aphids produce two types of saliva that mediate their interactions with plants. Watery saliva is secreted during cell penetration and ingestion, whereas gel saliva is secreted during stylet movement through the apoplast where it forms a sheath around the stylet to facilitate penetration and seal puncture sites on cell membranes. In order to study the function of the sheath when aphids interact with plants, we used RNA interference (RNAi) to silence the aphid structural sheath protein (SHP) in the pea aphid Acyrthosiphon pisum. The injection of 50 ng of double stranded RNA completely disrupted sheath formation, as confirmed by scanning electron microscopy. Aphid behavior was monitored using the electrical penetration graph technique, revealing that disrupted sheath formation prevented efficient long-term feeding from sieve tubes, with a silencing effect on reproduction but not survival. We propose that sealing the stylet penetration site in the sieve tube plasma membrane is part of a two-step mechanism to suppress sieve-tube occlusion by preventing calcium influx into the sieve tube lumen. The SHP is present in several aphid species and silencing has a similar impact to aphid-resistant plants, suggesting that SHP is an excellent target for RNAi-mediated pest control.

  7. Negative interaction between twospotted spider mites and aphids mediated by feeding damage and honeydew.

    PubMed

    Cédola, C V; Gugole Ottaviano, M F; Brentassi, M E; Cingolani, M F; Greco, N M

    2013-04-01

    Among the herbivorous arthropods that feed on strawberry, the most important are the two-spotted spider mite (TSSM), Tetranychus urticae Koch, and several species of aphids. Mites and aphids belong to different guilds that coexist in the field and feed on the undersides of strawberry leaflets. However, the occurrence of large numbers of individuals of both species on the same leaflet is rarely recorded. We hypothesize that negative interactions between TSSM and aphids explain the intraplant distribution of these herbivores. We first examined the spatial coincidence of both herbivores in the field. Under experimental conditions, we then analyzed: (i) the rate of increase of TSSM and the aphid Chaetosiphon fragaefolii (Cockerell), growing individually and together; (ii) the effect of honeydew on TSSM preference; and (iii) the effect of previous strawberry leaflet damage by TSSM on C. fragaefolii preference. The proportion of TSSM that coincided with at least one aphid decreased as the percentage of leaflets with TSSM increased. The spatial coincidence index between aphids and TSSM increased together with the percentage of TSSM-infested leaflets. TSSM showed both a lower rate of increase when they shared the same leaflet with C. fragaefolii and lower fecundity on strawberry discs with honeydew. The rate of increase of C. fragaefolii did not change on co-occupied leaves, but the aphid species moved to the other side of leaflets shared with TSSM. Negative interactions resulting in a tendency for species to avoid each other, such as demonstrated herein, can affect distribution and performance of herbivorous arthropods.

  8. A cost of alarm pheromone production in cotton aphids, Aphis gossypii

    NASA Astrophysics Data System (ADS)

    Byers, John A.

    2005-02-01

    The sesquiterpene, (E)-β-farnesene, is used by many aphid species as an alarm pheromone to warn related individuals of predation. Disturbed cotton aphids, Aphis gossypii Glover, released (E)-β-farnesene into the air as detected by solid phase microextraction and gas chromatography mass spectrometry (GC MS). Solvent extracts of cotton aphids of various life stages and weights also were analyzed by GC MS for sums of ions 69 and 93, which discriminated (E)-β-farnesene from coeluting compounds. Aphids of all life stages and sizes reared on cotton plants in both an environmental chamber and glasshouse contained (E)-β-farnesene in amounts ranging from 0.1 to 1.5 ng per individual. The quantities of (E)-β-farnesene in aphids increased in relation to increasing body weight, and variation in individual weights explained about 82% of the variation in alarm pheromone. However, the concentrations (ng/mg fresh weight) declined exponentially with increasing body weight. These findings indicate that aphid nymphs try to compensate for their smaller size by producing relatively more pheromone per weight than adults but still cannot approach an evolutionary optimal load, as assumed in adults with the greatest total amounts. This suggests that young aphids need to balance costs of growth and maturation with costs of producing the alarm pheromone.

  9. Unpredicted impacts of insect endosymbionts on interactions between soil organisms, plants and aphids.

    PubMed

    Hackett, Sean C; Karley, Alison J; Bennett, Alison E

    2013-10-07

    Ecologically significant symbiotic associations are frequently studied in isolation, but such studies of two-way interactions cannot always predict the responses of organisms in a community setting. To explore this issue, we adopt a community approach to examine the role of plant-microbial and insect-microbial symbioses in modulating a plant-herbivore interaction. Potato plants were grown under glass in controlled conditions and subjected to feeding from the potato aphid Macrosiphum euphorbiae. By comparing plant growth in sterile, uncultivated and cultivated soils and the performance of M. euphorbiae clones with and without the facultative endosymbiont Hamiltonella defensa, we provide evidence for complex indirect interactions between insect- and plant-microbial systems. Plant biomass responded positively to the live soil treatments, on average increasing by 15% relative to sterile soil, while aphid feeding produced shifts (increases in stem biomass and reductions in stolon biomass) in plant resource allocation irrespective of soil treatment. Aphid fecundity also responded to soil treatment with aphids on sterile soil exhibiting higher fecundities than those in the uncultivated treatment. The relative allocation of biomass to roots was reduced in the presence of aphids harbouring H. defensa compared with plants inoculated with H. defensa-free aphids and aphid-free control plants. This study provides evidence for the potential of plant and insect symbionts to shift the dynamics of plant-herbivore interactions.

  10. Nonrandom Distribution of Cabbage Aphids (Hemiptera: Aphididae) in Dryland Canola (Brassicales: Brassicaceae).

    PubMed

    Severtson, Dustin; Flower, Ken; Nansen, Christian

    2015-06-01

    Characterization of spatial distribution patterns of pests in large-scale agricultural fields is important because these patterns affect the sampling effort needed to accurately detect and estimate their population density. In this study, we conducted experimental releases of alate cabbage aphids (Brevicoryne brassicae L.) into centers of small plots of canola (Brassica napus L.), and their gradual spread over a 7-wk period was characterized. The small-plot experiment demonstrated gradient effects from plot centers and a nonrandom vertical distribution, with initial colonization occurring on the abaxial side of lower canopy leaves and, later, highest numbers of cabbage aphids occurring on racemes. We also conducted large-scale distribution analyses of cabbage aphid infestations in two commercial canola fields, using visual inspection and sweep net sampling. We used canola plant phenological and landscape features as explanatory variables of the spatial distribution of cabbage aphid counts. These large-scale experiments showed strong edge effects with negative associations between cabbage aphid counts and distance to crop edges, including tree lines and contour banks. Cabbage aphid distribution was more effectively displayed using logistic regression than ordinary regression, Spatial Analysis by Distance IndicEs, or both. Based on the study findings, a nonrandom or optimized inspection approach is proposed to focus monitoring efforts on canola plants within 20 m from field edges with particular attention to the abaxial side of lower-canopy leaves. Detection of advanced cabbage aphid infestations should target the racemes within 20 m from field edges.

  11. Direct and indirect effects of warming on aphids, their predators, and ant mutualists.

    PubMed

    Barton, Brandon T; Ives, Anthony R

    2014-06-01

    Species exist within communities of other interacting species, so an exogenous force that directly affects one species can indirectly affect all other members of the community. In the case of climate change, many species may be affected directly and subsequently initiate numerous indirect effects that propagate throughout the community. Therefore, the net effect of climate change on any one species is a function of the direct and indirect effects. We investigated the direct and indirect effects of climate warming on corn leaf aphids, a pest of corn and other grasses, by performing an experimental manipulation of temperature, predators, and two common aphid-tending ants. Although warming had a positive direct effect on aphid population growth rate, warming reduced aphid abundance when ants and predators were present. This occurred because winter ants, which aggressively defend aphids from predators under control temperatures, were less aggressive toward predators and less abundant when temperatures were increased. In contrast, warming increased the abundance of cornfield ants, but they did not protect aphids from predators with the same vigor as winter ants. Thus, warming broke down the ant-aphid mutualism and counterintuitively reduced the abundance of this agricultural pest.

  12. Differential expression of superoxide dismutase genes in aphid-stressed maize (Zea mays L.) seedlings.

    PubMed

    Sytykiewicz, Hubert

    2014-01-01

    The aim of this study was to compare the expression patterns of superoxide dismutase genes (sod2, sod3.4, sod9 and sodB) in seedling leaves of the Zea mays L. Tasty Sweet (susceptible) and Ambrozja (relatively resistant) cultivars infested with one of two hemipteran species, namely monophagous Sitobion avenae F. (grain aphid) or oligophagous Rhopalosiphum padi L. (bird cherry-oat aphid). Secondarily, aphid-elicited alternations in the antioxidative capacity towards DPPH (1,1-diphenyl-2-picrylhydrazyl) radical in insect-stressed plants were evaluated. Comprehensive comparison of expression profiles of the four sod genes showed that both insect species evoked significant upregulation of three genes sod2, sod3.4 and sod9). However, aphid infestation affected non-significant fluctuations in expression of sodB gene in seedlings of both maize genotypes. The highest levels of transcript accumulation occurred at 8 h (sod2 and sod3.4) or 24 h (sod9) post-infestation, and aphid-induced changes in the expression of sod genes were more dramatic in the Ambrozja cultivar than in the Tasty Sweet variety. Furthermore, bird cherry-oat aphid colonization had a more substantial impact on levels of DPPH radical scavenging activity in infested host seedlings than grain aphid colonization. Additionally, Ambrozja plants infested by either hemipteran species showed markedly lower antioxidative capacity compared with attacked Tasty Sweet plants.

  13. A cost of alarm pheromone production in cotton aphids, Aphis gossypii.

    PubMed

    Byers, John A

    2005-02-01

    The sesquiterpene, (E)-beta-farnesene, is used by many aphid species as an alarm pheromone to warn related individuals of predation. Disturbed cotton aphids, Aphis gossypii Glover, released (E)-beta-farnesene into the air as detected by solid phase microextraction and gas chromatography mass spectrometry (GC-MS). Solvent extracts of cotton aphids of various life stages and weights also were analyzed by GC-MS for sums of ions 69 and 93, which discriminated (E)-beta-farnesene from coeluting compounds. Aphids of all life stages and sizes reared on cotton plants in both an environmental chamber and glasshouse contained (E)-beta-farnesene in amounts ranging from 0.1 to 1.5 ng per individual. The quantities of (E)-beta-farnesene in aphids increased in relation to increasing body weight, and variation in individual weights explained about 82% of the variation in alarm pheromone. However, the concentrations (ng/mg fresh weight) declined exponentially with increasing body weight. These findings indicate that aphid nymphs try to compensate for their smaller size by producing relatively more pheromone per weight than adults but still cannot approach an evolutionary optimal load, as assumed in adults with the greatest total amounts. This suggests that young aphids need to balance costs of growth and maturation with costs of producing the alarm pheromone.

  14. Cucumis melo microRNA expression profile during aphid herbivory in a resistant and susceptible interaction.

    PubMed

    Sattar, Sampurna; Song, Yan; Anstead, James A; Sunkar, Ramanjulu; Thompson, Gary A

    2012-06-01

    Aphis gossypii resistance in melon (Cucumis melo) is due to the presence of a single dominant virus aphid transmission (Vat) gene belonging to the nucleotide-binding site leucine-rich repeat family of resistance genes. Significant transcriptional reprogramming occurs in Vat(+) plants during aphid infestation as metabolism shifts to respond to this biotic stress. MicroRNAs (miRNAs) are involved in the regulation of many biotic stress responses. The role of miRNAs was investigated in response to aphid herbivory during both resistant and susceptible interactions. Small RNA (smRNA) libraries were constructed from bulked leaf tissues of a Vat(+) melon line following early and late aphid infestations. Sequence analysis indicated that the expression profiles of conserved and newly identified miRNAs were altered during different stages of aphid herbivory. These results were verified by quantitative polymerase chain reaction experiments in both resistant Vat(+) and susceptible Vat(-) interactions. The comparative analyses revealed that most of the conserved miRNA families were differentially regulated during the early stages of aphid infestation in the resistant and susceptible interactions. Along with the conserved miRNA families, 18 cucurbit-specific miRNAs were expressed during the different stages of aphid herbivory. The comparison of the miRNA profiles in the resistant and susceptible interactions provides insight into the miRNA-dependent post-transcriptional gene regulation in Vat-mediated resistance.

  15. AtWRKY22 promotes susceptibility to aphids and modulates salicylic acid and jasmonic acid signalling.

    PubMed

    Kloth, Karen J; Wiegers, Gerrie L; Busscher-Lange, Jacqueline; van Haarst, Jan C; Kruijer, Willem; Bouwmeester, Harro J; Dicke, Marcel; Jongsma, Maarten A

    2016-05-01

    Aphids induce many transcriptional perturbations in their host plants, but the signalling cascades responsible and the effects on plant resistance are largely unknown. Through a genome-wide association (GWA) mapping study in Arabidopsis thaliana, we identified WRKY22 as a candidate gene associated with feeding behaviour of the green peach aphid, Myzus persicae The transcription factor WRKY22 is known to be involved in pathogen-triggered immunity, and WRKY22 gene expression has been shown to be induced by aphids. Assessment of aphid population development and feeding behaviour on knockout mutants and overexpression lines showed that WRKY22 increases susceptibility to M. persicae via a mesophyll-located mechanism. mRNA sequencing analysis of aphid-infested wrky22 knockout plants revealed the up-regulation of genes involved in salicylic acid (SA) signalling and down-regulation of genes involved in plant growth and cell-wall loosening. In addition, mechanostimulation of knockout plants by clip cages up-regulated jasmonic acid (JA)-responsive genes, resulting in substantial negative JA-SA crosstalk. Based on this and previous studies, WRKY22 is considered to modulate the interplay between the SA and JA pathways in response to a wide range of biotic and abiotic stimuli. Its induction by aphids and its role in suppressing SA and JA signalling make WRKY22 a potential target for aphids to manipulate host plant defences. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  16. Unpredicted impacts of insect endosymbionts on interactions between soil organisms, plants and aphids

    PubMed Central

    Hackett, Sean C.; Karley, Alison J.; Bennett, Alison E.

    2013-01-01

    Ecologically significant symbiotic associations are frequently studied in isolation, but such studies of two-way interactions cannot always predict the responses of organisms in a community setting. To explore this issue, we adopt a community approach to examine the role of plant–microbial and insect–microbial symbioses in modulating a plant–herbivore interaction. Potato plants were grown under glass in controlled conditions and subjected to feeding from the potato aphid Macrosiphum euphorbiae. By comparing plant growth in sterile, uncultivated and cultivated soils and the performance of M. euphorbiae clones with and without the facultative endosymbiont Hamiltonella defensa, we provide evidence for complex indirect interactions between insect– and plant–microbial systems. Plant biomass responded positively to the live soil treatments, on average increasing by 15% relative to sterile soil, while aphid feeding produced shifts (increases in stem biomass and reductions in stolon biomass) in plant resource allocation irrespective of soil treatment. Aphid fecundity also responded to soil treatment with aphids on sterile soil exhibiting higher fecundities than those in the uncultivated treatment. The relative allocation of biomass to roots was reduced in the presence of aphids harbouring H. defensa compared with plants inoculated with H. defensa-free aphids and aphid-free control plants. This study provides evidence for the potential of plant and insect symbionts to shift the dynamics of plant–herbivore interactions. PMID:23926148

  17. Indirect effect of a transgenic wheat on aphids through enhanced powdery mildew resistance.

    PubMed

    von Burg, Simone; Álvarez-Alfageme, Fernando; Romeis, Jörg

    2012-01-01

    In agricultural ecosystems, arthropod herbivores and fungal pathogens are likely to colonise the same plant and may therefore affect each other directly or indirectly. The fungus that causes powdery mildew (Blumeria graminis tritici) and cereal aphids are important pests of wheat but interactions between them have seldom been investigated. We studied the effects of powdery mildew of wheat on two cereal aphid species, Metopolophium dirhodum and Rhopalosiphum padi. We hypothesized that aphid number and size will be smaller on powdery mildew-infected plants than on non-infected plants. In a first experiment we used six commercially available wheat varieties whereas in the second experiment we used a genetically modified (GM) mildew-resistant wheat line and its non-transgenic sister line. Because the two lines differed only in the presence of the transgene and in powdery mildew resistance, experiment 2 avoided the confounding effect of variety. In both experiments, the number of M. dirhodum but not of R. padi was reduced by powdery mildew infection. Transgenic mildew-resistant lines therefore harboured bigger aphid populations than the non-transgenic lines. For both aphid species individual size was mostly influenced by aphid number. Our results indicate that plants that are protected from a particular pest (powdery mildew) became more favourable for another pest (aphids).

  18. Change in Biotypic Diversity of Russian Wheat Aphid (Hemiptera: Aphididae) Populations in the United States.

    PubMed

    Puterka, G J; Giles, K L; Brown, M J; Nicholson, S J; Hammon, R W; Peairs, F B; Randolph, T L; Michaels, G J; Bynum, E D; Springer, T L; Armstrong, J S; Mornhinweg, D W

    2015-04-01

    A key component of Russian wheat aphid, Diuraphis noxia (Kurdjumov), management has been through planting resistant wheat cultivars. A new biotype, RWA2, appeared in 2003 which caused widespread damage to wheat cultivars containing the Dn4 gene. Biotypic diversity in Russian wheat aphid populations has not been addressed since 2005 when RWA2 dominated the biotype complex. Our objectives were to determine the biotypic diversity in the Central Great Plains and Colorado Plateau at regional (2010, 2011, 2013) and local (2012) levels and detect the presence of new Russian wheat aphid biotypes. Regional and within-field aphid collections were screened against Russian wheat aphid-resistant wheat genotypes containing genes Dn3, Dn4, Dn6, Dn7, Dn9, CI2401; and resistant barley STARS 9301B. In 2010, all aphid collections from Texas were avirulent to the Dn4 resistance gene in wheat. Regional results revealed Dn4 avirulent RWA6 was widespread (55-84%) in populations infesting wheat in both regions. Biotypes RWA1, 2, and 3/7 were equally represented with percentages<20% each while RWA8 was rarely detected. Combining percentages of RWA1, 6, and 8 across regions to estimate avirulence to Dn4 gene revealed high percentages for both 2011 (64-80%) and 2013 (69-90%). In contrast, the biotype structure at the local level differed where biotype percentages varied up to ≥2-fold between fields. No new biotypes were detected; therefore, Dn7, CI2401, and STARS9301B remained resistant to all known Russian wheat aphid biotypes. This study documents a shift to Dn4 avirulent biotypes and serves as a valuable baseline for biotypic diversity in Russian wheat aphid populations prior to the deployment of new Russian wheat aphid-resistant wheat cultivars.

  19. Multitrophic interactions involving genetically modified potatoes, nontarget aphids, natural enemies and hyperparasitoids.

    PubMed

    Cowgill, S E; Danks, C; Atkinson, H J

    2004-03-01

    Genetically modified (GM) potatoes expressing a cysteine proteinase inhibitor (cystatin) have been developed as an option for the management of plant parasitic nematodes. The relative impact of such plants on predators and parasitoids (natural enemies) of nontarget insects was determined in a field trial. The trial consisted of GM plants, control plants grown in soil treated with a nematicide and untreated control plants. The quantity of nontarget aphids and their quality as hosts for natural enemies were studied. Aphid density was significantly reduced by nematicide treatment and few natural enemies were recorded from treated potatoes during the study. In contrast, similar numbers of aphids and their more abundant predators were recorded from the untreated control and the GM potatoes. The size of aphids on GM and control plants was recorded twice during the study. During the first sampling period (2-9 July) aphids clip-caged on GM plants were smaller than those on control plants. During the second sampling period (23-30 July) there was no difference in aphid size between those from the GM and control plants. Host size is an important component of host quality. It can affect the size and fecundity of parasitoid females and the sex ratio of their offspring. However, neither the fitness of females of Aphidius ervi, the most prevalent primary parasitoid, nor the sex ratio of their progeny, were affected when the parasitoids developed on aphids feeding on GM plants. Two guilds of secondary parasitoid were also recorded during the study. The fitness of the most abundant species, Aspahes vulgaris, was not affected when it developed on hosts from GM plants. The transgene product, OC I Delta D86, was not detected in aphids that had fed on GM plants in the field, suggesting that there is minimal secondary exposure of natural enemies to the inhibitor. The results indicate that transgenic nematode resistance is potentially more compatible with aphid biological control than is

  20. A Dietary Test of Putative Deleterious Sterols for the Aphid Myzus persicae

    PubMed Central

    Bouvaine, Sophie; Faure, Marie-Line; Grebenok, Robert J.; Behmer, Spencer T.; Douglas, Angela E.

    2014-01-01

    The aphid Myzus persicae displays high mortality on tobacco plants bearing a transgene which results in the accumulation of the ketosteroids cholestan-3-one and cholest-4-en-3-one in the phloem sap. To test whether the ketosteroids are the basis of the plant resistance to the aphids, M. persicae were reared on chemically-defined diets with different steroid contents at 0.1–10 µg ml−1. Relative to sterol-free diet and dietary supplements of the two ketosteroids and two phytosterols, dietary cholesterol significantly extended aphid lifespan and increased fecundity at one or more dietary concentrations tested. Median lifespan was 50% lower on the diet supplemented with cholest-4-en-3-one than on the cholesterol-supplemented diet. Aphid feeding rate did not vary significantly across the treatments, indicative of no anti-feedant effect of any sterol/steroid. Aphids reared on diets containing equal amounts of cholesterol and cholest-4-en-3-one showed fecundity equivalent to aphids on diets containing only cholesterol. Aphids were reared on diets that reproduced the relative steroid abundance in the phloem sap of the control and modified tobacco plants, and their performance on the two diet formulations was broadly equivalent. We conclude that, at the concentrations tested, plant ketosteroids support weaker aphid performance than cholesterol, but do not cause acute toxicity to the aphids. In plants, the ketosteroids may act synergistically with plant factors absent from artificial diets but are unlikely to be solely responsible for resistance of modified tobacco plants. PMID:24465993

  1. Stress-induced changes in abundance differ among obligate and facultative endosymbionts of the soybean aphid.

    PubMed

    Enders, Laramy S; Miller, Nicholas J

    2016-02-01

    Bacterial endosymbionts can drive evolutionary novelty by conferring adaptive benefits under adverse environmental conditions. Among aphid species there is growing evidence that symbionts influence tolerance to various forms of stress. However, the extent to which stress inflicted on the aphid host has cascading effects on symbiont community dynamics remains poorly understood. Here we simultaneously quantified the effect of host-plant induced and xenobiotic stress on soybean aphid (Aphis glycines) fitness and relative abundance of its three bacterial symbionts. Exposure to soybean defensive stress (Rag1 gene) and a neurotoxic insecticide (thiamethoxam) substantially reduced aphid composite fitness (survival × reproduction) by 74 ± 10% and 92 ± 2%, respectively, which in turn induced distinctive changes in the endosymbiont microbiota. When challenged by host-plant defenses a 1.4-fold reduction in abundance of the obligate symbiont Buchnera was observed across four aphid clonal lines. Among facultative symbionts of Rag1-stressed aphids, Wolbachia abundance increased twofold and Arsenophonus decreased 1.5-fold. A similar pattern was observed under xenobiotic stress, with Buchnera and Arsenophonus titers decreasing (1.3-fold) and Wolbachia increasing (1.5-fold). Furthermore, variation in aphid virulence to Rag1 was positively correlated with changes in Arsenophonus titers, but not Wolbachia or Buchnera. A single Arsenophonus multi-locus genotype was found among aphid clonal lines, indicating strain diversity is not primarily responsible for correlated host-symbiont stress levels. Overall, our results demonstrate the nature of aphid symbioses can significantly affect the outcome of interactions under stress and suggests general changes in the microbiome can occur across multiple stress types.

  2. Soil pathogen-aphid interactions under differences in soil organic matter and mineral fertilizer

    PubMed Central

    Marini, Lorenzo; Biere, Arjen; van Agtmaal, Maaike; Tyc, Olaf; Kos, Martine; Kleijn, David; van der Putten, Wim H.

    2017-01-01

    There is increasing evidence showing that microbes can influence plant-insect interactions. In addition, various studies have shown that aboveground pathogens can alter the interactions between plants and insects. However, little is known about the role of soil-borne pathogens in plant-insect interactions. It is also not known how environmental conditions, that steer the performance of soil-borne pathogens, might influence these microbe-plant-insect interactions. Here, we studied effects of the soil-borne pathogen Rhizoctonia solani on aphids (Sitobion avenae) using wheat (Triticum aestivum) as a host. In a greenhouse experiment, we tested how different levels of soil organic matter (SOM) and fertilizer addition influence the interactions between plants and aphids. To examine the influence of the existing soil microbiome on the pathogen effects, we used both unsterilized field soil and sterilized field soil. In unsterilized soil with low SOM content, R. solani addition had a negative effect on aphid biomass, whereas it enhanced aphid biomass in soil with high SOM content. In sterilized soil, however, aphid biomass was enhanced by R. solani addition and by high SOM content. Plant biomass was enhanced by fertilizer addition, but only when SOM content was low, or in the absence of R. solani. We conclude that belowground pathogens influence aphid performance and that the effect of soil pathogens on aphids can be more positive in the absence of a soil microbiome. This implies that experiments studying the effect of pathogens under sterile conditions might not represent realistic interactions. Moreover, pathogen-plant-aphid interactions can be more positive for aphids under high SOM conditions. We recommend that soil conditions should be taken into account in the study of microbe-plant-insect interactions. PMID:28817594

  3. An aphid's Odyssey--the cortical quest for the vascular bundle.

    PubMed

    Hewer, Angela; Becker, Alexander; van Bel, Aart J E

    2011-11-15

    Sensing pH and sucrose concentration (with a preference for pH values of 7.0-7.5 and sucrose concentrations of approximately 400 mmol l(-1)) enables aphids to recognise sieve tubes inside vascular bundles. However, it is still unclear how aphids find their way to the vascular bundles. Membrane potentials in the cortex of Vicia faba stems were measured along a radial transect from the epidermis to the sieve elements and there was no gradient detected that could be used by aphids to guide their stylets to the sieve elements. Additionally, aphids did not demonstrate a preference between artificial diets with low or high levels of dissolved oxygen, making it unlikely that oxygen gradients in the cortex assist orientation towards the phloem. Tracks of salivary sheaths indicate that aphids search for vascular bundles in a radial direction (perpendicular from the stem surface to the vascular bundle) with regular side punctures in a pre-programmed fashion. Optical examination and electrical penetration graph (EPG) recordings suggest that aphids (Megoura viciae) probe the vacuolar sap of cortex cells. Acidic pH (5.0-5.5) and low sucrose concentrations in vacuoles, therefore, may provoke aphids to retract their stylets and probe the next cell until a favourable cell sap composition is encountered. The importance of sucrose as a cue was demonstrated by the experimental manipulation of Ricinus communis plants that cause them to transport hexoses instead of sucrose. Aphids (Aphis fabae) ingested less phloem sap of plants transporting hexoses compared with plants transporting the normal sucrose. The proposed rejection-acceptance behaviour provides a universal plant-directed mode of how aphids orientate their stylets towards the phloem.

  4. Comparing growth patterns among field populations of cereal aphids reveals factors limiting their maximum abundance.

    PubMed

    Honek, A; Jarosik, V; Dixon, A F G

    2006-06-01

    Cereal stands in central Europe are commonly infested with three species of aphids that may become serious pests. With increasing abundance, the proportion of a particular species in the total aphid population may remain constant, suggesting a density-independent exponential growth, or the proportion can change, suggesting density-dependent constraints on growth. The constraints that affect particular species, and thus their relative abundance, were studied. The proportionality between maximum abundances of the cereal aphids was studied using a 10-year census of the numbers of aphids infesting 268 winter wheat plots. For two species their abundance on leaves and ears was compared. With increasing aphid density the maximum abundance of Rhopalosiphum padi (Linnaeus) remained proportional, but not that of Sitobion avenae (Fabricius), which was constrained by the smaller surface area of ears compared to leaves. There was no evidence of inter-specific competition. Maximum abundance of R. padi and Metopolophium dirhodum (Walker) on leaves did not change proportionally as the proportion of M. dirhodum decreased with increasing overall aphid density. This decrease was probably caused by the restricted distribution of M. dirhodum, which is confined to leaves, where space is limiting. No change in proportion between populations was detected when the average densities were below 0.54 aphids per leaf or ear. Non-proportional relationships between aphid populations appeared to be due to spatial constraints, acting upon the more abundant population. Detecting the limitation of population growth can help with the assessment of when density-independent exponential growth is limited by density-dependent factors. This information may help in the development of models of cereal aphid population dynamics.

  5. Widespread infection and diverse infection patterns of Wolbachia in Chinese aphids.

    PubMed

    Wang, Zhe; Su, Xiao-Min; Wen, Juan; Jiang, Li-Yun; Qiao, Ge-Xia

    2014-06-01

    Wolbachia are intracellular symbionts that infect a wide range of arthropods and filarial nematodes. Aphids are engaged in diverse and complex relationships with their endosymbionts. Four supergroups (A, B, M and N) of Wolbachia were previously detected in aphids and supergroups M and N were only found in aphids. In this study, we detected and described Wolbachia infections in natural populations of aphids in China. Three supergroups (A, B and M) were found in the examined aphid species. Supergroup M was preponderant, whereas supergroups A and B were only detected in certain species. Supergroup N was not found in this study. There were four infection patterns of Wolbachia in aphids, namely, infection with supergroup M alone, co-infection with supergroups A and M, co-infection with supergroups B and M, and co-infection with supergroups A, B and M. The pattern of infection only with supergroup M was universal and was found in all evaluated subfamilies. Only two subfamilies, Aphidinae and Lachninae, manifested to present all four infection patterns. Three patterns were observed in Calaphidinae (M, A&M, B&M) and Eriosomatinae (M, B&M, A&B&M). Two patterns were observed in the Anoeciinae (M, A&M) and Greenideinae (M, B&M), and only one pattern (M) was observed in the remaining families and/or subfamilies of Aphidoidea. These results indicated that Wolbachia infections in Chinese aphids are widespread. Phylogenetic analyses suggest that Wolbachia supergroup M spread rapidly and recently among all host species of aphids in China. Reasons for this spread and its mechanisms are discussed along with the possible effects of Wolbachia on their aphid hosts.

  6. Gene Family Expansions in Aphids Maintained by Endosymbiotic and Nonsymbiotic Traits.

    PubMed

    Duncan, Rebecca P; Feng, Honglin; Nguyen, Douglas M; Wilson, Alex C C

    2016-02-15

    Facilitating the evolution of new gene functions, gene duplication is a major mechanism driving evolutionary innovation. Gene family expansions relevant to host/symbiont interactions are increasingly being discovered in eukaryotes that host endosymbiotic microbes. Such discoveries entice speculation that gene duplication facilitates the evolution of novel, endosymbiotic relationships. Here, using a comparative transcriptomic approach combined with differential gene expression analysis, we investigate the importance of endosymbiosis in retention of amino acid transporter paralogs in aphid genomes. To pinpoint the timing of amino acid transporter duplications we inferred gene phylogenies for five aphid species and three outgroups. We found that while some duplications arose in the aphid common ancestor concurrent with endosymbiont acquisition, others predate aphid divergence from related insects without intracellular symbionts, and still others appeared during aphid diversification. Interestingly, several aphid-specific paralogs have conserved enriched expression in bacteriocytes, the insect cells that host primary symbionts. Conserved bacteriocyte enrichment suggests that the transporters were recruited to the aphid/endosymbiont interface in the aphid common ancestor, consistent with a role for gene duplication in facilitating the evolution of endosymbiosis in aphids. In contrast, the temporal variability of amino acid transporter duplication indicates that endosymbiosis is not the only trait driving selection for retention of amino acid transporter paralogs in sap-feeding insects. This study cautions against simplistic interpretations of the role of gene family expansion in the evolution of novel host/symbiont interactions by further highlighting that multiple complex factors maintain gene family paralogs in the genomes of eukaryotes that host endosymbiotic microbes.

  7. Host Plant Determines the Population Size of an Obligate Symbiont (Buchnera aphidicola) in Aphids.

    PubMed

    Zhang, Yuan-Chen; Cao, Wen-Jie; Zhong, Le-Rong; Godfray, H Charles J; Liu, Xiang-Dong

    2016-04-01

    Buchnera aphidicolais an obligate endosymbiont that provides aphids with several essential nutrients. Though much is known about aphid-Buchnera interactions, the effect of the host plant on Buchnera population size remains unclear. Here we used quantitative PCR (qPCR) techniques to explore the effects of the host plant on Buchnera densities in the cotton-melon aphid, Aphis gossypii Buchneratiters were significantly higher in populations that had been reared on cucumber for over 10 years than in populations maintained on cotton for a similar length of time. Aphids collected in the wild from hibiscus and zucchini harbored more Buchnera symbionts than those collected from cucumber and cotton. The effect of aphid genotype on the population size of Buchnera depended on the host plant upon which they fed. When aphids from populations maintained on cucumber or cotton were transferred to novel host plants, host survival and Buchnera population size fluctuated markedly for the first two generations before becoming relatively stable in the third and later generations. Host plant extracts from cucumber, pumpkin, zucchini, and cowpea added to artificial diets led to a significant increase in Buchnera titers in the aphids from the population reared on cotton, while plant extracts from cotton and zucchini led to a decrease in Buchnera titers in the aphids reared on cucumber. Gossypol, a secondary metabolite from cotton, suppressed Buchnera populations in populations from both cotton and cucumber, while cucurbitacin from cucurbit plants led to higher densities. Together, the results suggest that host plants influence Buchnera population processes and that this may provide phenotypic plasticity in host plant use for clonal aphids.

  8. Gene Family Expansions in Aphids Maintained by Endosymbiotic and Nonsymbiotic Traits

    PubMed Central

    Duncan, Rebecca P.; Feng, Honglin; Nguyen, Douglas M.; Wilson, Alex C. C.

    2016-01-01

    Facilitating the evolution of new gene functions, gene duplication is a major mechanism driving evolutionary innovation. Gene family expansions relevant to host/symbiont interactions are increasingly being discovered in eukaryotes that host endosymbiotic microbes. Such discoveries entice speculation that gene duplication facilitates the evolution of novel, endosymbiotic relationships. Here, using a comparative transcriptomic approach combined with differential gene expression analysis, we investigate the importance of endosymbiosis in retention of amino acid transporter paralogs in aphid genomes. To pinpoint the timing of amino acid transporter duplications we inferred gene phylogenies for five aphid species and three outgroups. We found that while some duplications arose in the aphid common ancestor concurrent with endosymbiont acquisition, others predate aphid divergence from related insects without intracellular symbionts, and still others appeared during aphid diversification. Interestingly, several aphid-specific paralogs have conserved enriched expression in bacteriocytes, the insect cells that host primary symbionts. Conserved bacteriocyte enrichment suggests that the transporters were recruited to the aphid/endosymbiont interface in the aphid common ancestor, consistent with a role for gene duplication in facilitating the evolution of endosymbiosis in aphids. In contrast, the temporal variability of amino acid transporter duplication indicates that endosymbiosis is not the only trait driving selection for retention of amino acid transporter paralogs in sap-feeding insects. This study cautions against simplistic interpretations of the role of gene family expansion in the evolution of novel host/symbiont interactions by further highlighting that multiple complex factors maintain gene family paralogs in the genomes of eukaryotes that host endosymbiotic microbes. PMID:26878871

  9. Host Plant Determines the Population Size of an Obligate Symbiont (Buchnera aphidicola) in Aphids

    PubMed Central

    Zhang, Yuan-Chen; Cao, Wen-Jie; Zhong, Le-Rong; Godfray, H. Charles J.

    2016-01-01

    Buchnera aphidicola is an obligate endosymbiont that provides aphids with several essential nutrients. Though much is known about aphid-Buchnera interactions, the effect of the host plant on Buchnera population size remains unclear. Here we used quantitative PCR (qPCR) techniques to explore the effects of the host plant on Buchnera densities in the cotton-melon aphid, Aphis gossypii. Buchnera titers were significantly higher in populations that had been reared on cucumber for over 10 years than in populations maintained on cotton for a similar length of time. Aphids collected in the wild from hibiscus and zucchini harbored more Buchnera symbionts than those collected from cucumber and cotton. The effect of aphid genotype on the population size of Buchnera depended on the host plant upon which they fed. When aphids from populations maintained on cucumber or cotton were transferred to novel host plants, host survival and Buchnera population size fluctuated markedly for the first two generations before becoming relatively stable in the third and later generations. Host plant extracts from cucumber, pumpkin, zucchini, and cowpea added to artificial diets led to a significant increase in Buchnera titers in the aphids from the population reared on cotton, while plant extracts from cotton and zucchini led to a decrease in Buchnera titers in the aphids reared on cucumber. Gossypol, a secondary metabolite from cotton, suppressed Buchnera populations in populations from both cotton and cucumber, while cucurbitacin from cucurbit plants led to higher densities. Together, the results suggest that host plants influence Buchnera population processes and that this may provide phenotypic plasticity in host plant use for clonal aphids. PMID:26850304

  10. BOTRYTIS-INDUCED KINASE1 Modulates Arabidopsis Resistance to Green Peach Aphids via PHYTOALEXIN DEFICIENT4.

    PubMed

    Lei, Jiaxin; A Finlayson, Scott; Salzman, Ron A; Shan, Libo; Zhu-Salzman, Keyan

    2014-08-01

    BOTRYTIS-INDUCED KINASE1 (BIK1) plays important roles in induced defense against fungal and bacterial pathogens in Arabidopsis (Arabidopsis thaliana). Its tomato (Solanum lycopersicum) homolog is required for host plant resistance to a chewing insect herbivore. However, it remains unknown whether BIK1 functions in plant defense against aphids, a group of insects with a specialized phloem sap-feeding style. In this study, the potential role of BIK1 was investigated in Arabidopsis infested with the green peach aphid (Myzus persicae). In contrast to the previously reported positive role of intact BIK1 in defense response, loss of BIK1 function adversely impacted aphid settling, feeding, and reproduction. Relative to wild-type plants, bik1 displayed higher aphid-induced hydrogen peroxide accumulation and more severe lesions, resembling a hypersensitive response (HR) against pathogens. These symptoms were limited to the infested leaves. The bik1 mutant showed elevated basal as well as induced salicylic acid and ethylene accumulation. Intriguingly, elevated salicylic acid levels did not contribute to the HR-like symptoms or to the heightened aphid resistance associated with the bik1 mutant. Elevated ethylene levels in bik1 accounted for an initial, short-term repellence. Introducing a loss-of-function mutation in the aphid resistance and senescence-promoting gene PHYTOALEXIN DEFICIENT4 (PAD4) into the bik1 background blocked both aphid resistance and HR-like symptoms, indicating bik1-mediated resistance to aphids is PAD4 dependent. Taken together, Arabidopsis BIK1 confers susceptibility to aphid infestation through its suppression of PAD4 expression. Furthermore, the results underscore the role of reactive oxygen species and cell death in plant defense against phloem sap-feeding insects. © 2014 American Society of Plant Biologists. All Rights Reserved.

  11. Expression of α-DIOXYGENASE 1 in tomato and Arabidopsis contributes to plant defenses against aphids.

    PubMed

    Avila, Carlos Augusto; Arevalo-Soliz, Lirio Milenka; Lorence, Argelia; Goggin, Fiona L

    2013-08-01

    Plant α-dioxygenases (α-DOX) are fatty acid-hydroperoxidases that contribute to the synthesis of oxylipins, a diverse group of compounds primarily generated through oxidation of linoleic (LA) and linolenic acid (LNA). Oxylipins are implicated in plant signaling against biotic and abiotic stresses. We report here that the potato aphid (Macrosiphum euphorbiae) induces Slα-DOX1 but not Slα-DOX2 expression in tomato (Solanum lycopersicum). Slα-DOX1 upregulation by aphids does not require either jasmonic acid (JA) or salicylic acid (SA) accumulation, since tomato mutants deficient in JA (spr2, acx1) or SA accumulation (NahG) still show Slα-DOX1 induction. Virus-induced gene silencing of Slα-DOX1 enhanced aphid population growth in wild-type (WT) plants, revealing that Slα-DOX1 contributes to basal resistance to aphids. Moreover, an even higher percent increase in aphid numbers occurred when Slα-DOX1 was silenced in spr2, a mutant line characterized by elevated LA levels, decreased LNA, and enhanced aphid resistance as compared with WT. These results suggest that aphid reproduction is influenced by oxylipins synthesized from LA by Slα-DOX1. In agreement with our experiments in tomato, two independent α-dox1 T-DNA insertion mutant lines in Arabidopsis thaliana also showed increased susceptibility to the green peach aphid (Myzus persicae), indicating that the role α-DOX is conserved in other plant-aphid interactions.

  12. Novel male-biased expression in paralogs of the aphid slimfast nutrient amino acid transporter expansion

    PubMed Central

    2011-01-01

    Background A major goal of molecular evolutionary biology is to understand the fate and consequences of duplicated genes. In this context, aphids are intriguing because the newly sequenced pea aphid genome harbors an extraordinary number of lineage-specific gene duplications relative to other insect genomes. Though many of their duplicated genes may be involved in their complex life cycle, duplications in nutrient amino acid transporters appear to be associated rather with their essential amino acid poor diet and the intracellular symbiosis aphids rely on to compensate for dietary deficits. Past work has shown that some duplicated amino acid transporters are highly expressed in the specialized cells housing the symbionts, including a paralog of an aphid-specific expansion homologous to the Drosophila gene slimfast. Previous data provide evidence that these bacteriocyte-expressed transporters mediate amino acid exchange between aphids and their symbionts. Results We report that some nutrient amino acid transporters show male-biased expression. Male-biased expression characterizes three paralogs in the aphid-specific slimfast expansion, and the male-biased expression is conserved across two aphid species for at least two paralogs. One of the male-biased paralogs has additionally experienced an accelerated rate of non-synonymous substitutions. Conclusions This is the first study to document male-biased slimfast expression. Our data suggest that the male-biased aphid slimfast paralogs diverged from their ancestral function to fill a functional role in males. Furthermore, our results provide evidence that members of the slimfast expansion are maintained in the aphid genome not only for the previously hypothesized role in mediating amino acid exchange between the symbiotic partners, but also for sex-specific roles. PMID:21917168

  13. Does Aphid Infestation Interfere with Indirect Plant Defense against Lepidopteran Caterpillars in Wild Cabbage?

    PubMed

    Li, Yehua; Weldegergis, Berhane T; Chamontri, Surachet; Dicke, Marcel; Gols, Rieta

    2017-04-12

    Attraction of parasitoids to plant volatiles induced by multiple herbivory depends on the specific combinations of attacking herbivore species, especially when their feeding modes activate different defense signalling pathways as has been reported for phloem feeding aphids and tissue feeding caterpillars. We studied the effects of pre-infestation with non-host aphids (Brevicoryne brassicae) for two different time periods on the ability of two parasitoid species to discriminate between volatiles emitted by plants infested by host caterpillars alone and those emitted by plants infested with host caterpillars plus aphids. Using plants originating from three chemically distinct wild cabbage (Brassica oleracea) populations, Diadegma semiclausum switched preference for dually infested plants to preference for plants infested with Plutella xylostella hosts alone when the duration of pre-aphid infestation doubled from 7 to 14 days. Microplitis mediator, a parasitoid of Mamestra brassicae caterpillars, preferred dually-infested plants irrespective of aphid-infestation duration. Separation of the volatile blends emitted by plants infested with hosts plus aphids or with hosts only was poor, based on multivariate statistics. However, emission rates of individual compounds were often reduced in plants infested with aphids plus hosts compared to those emitted by plants infested with hosts alone. This effect depended on host caterpillar species and plant population and was little affected by aphid infestation duration. Thus, the interactive effect of aphids and hosts on plant volatile production and parasitoid attraction can be dynamic and parasitoid specific. The characteristics of the multi-component volatile blends that determine parasitoid attraction are too complex to be deduced from simple correlative statistical analyses.

  14. Regulation of aphid populations by aphidiid wasps: does parasitoid foraging behaviour or hyperparasitism limit impact?

    PubMed

    Mackauer, M; Völkl, W

    1993-06-01

    Aphidiid parasitoids (Hymenoptera: Aphidiidae) of aphids generally exploit only a small percentage of the available host resources in the field. This limited impact on aphid populations has often been explained as a consequence of hyperparasitism. We propose that a wasp's reproductive strategy, as opposed to hyperparasitism, is the dominant factor in aphidiid population dynamics. A wasp's foraging efficiency and oviposition decisions are influenced by several variables, including searching behaviour between and within patches, host choice (as modified by the aphids' defensive behaviours), and plant structural complexity. Two broadly different patterns of host exploitation have evolved in aphidiid wasps in relation to ant-aphid mutualism. Firstly, in species that are exposed to predation and hyperparasitism, a female may leave a patch before all suitable hosts are parasitized. Because predators and hyperparasitoids tend to aggregate at high aphid or aphidiid densities, or in response to aphid honeydew, this strategy enables females to reduce offspring mortality by "spreading the risk" over several host patches. Secondly, in species that have evolved mechanisms to avoid aggression by mutualistic ants, females are able to exploit a hyperparasitoid-free resource space. Such species may concentrate their eggs in only a few aphid colonies, which are thus heavily exploited. Although hyperparasitism of species in the first group tends to reach high levels, its overall impact on aphid-aphidiid population dynamics is probably limited by the low average fecundity of most hyperparasitoids. We discuss the foraging patterns of aphidiid wasps in relation to aphid population regulation in general, and to classical biological control in particular. We argue that a parasitoid's potential to regulate the host population is largely determined by its foraging strategy. In an exotic parasitoid, a behavioural syndrome that has evolved and presumably is adaptive in a more diverse (native

  15. Differential Life History Trait Associations of Aphids with Nonpersistent Viruses in Cucurbits.

    PubMed

    Angelella, G M; Egel, D S; Holland, J D; Nemacheck, J A; Williams, C E; Kaplan, I

    2015-06-01

    The diversity of vectors and fleeting nature of virus acquisition and transmission renders nonpersistent viruses a challenge to manage. We assessed the importance of noncolonizing versus colonizing vectors with a 2-yr survey of aphids and nonpersistent viruses on commercial pumpkin farms. We quantified aphid alightment using pan traps, while testing leaf samples with multiplex RT-PCR targeting cucumber mosaic virus (CMV), zucchini yellow mosaic virus (ZYMV), watermelon mosaic virus (WMV), and papaya ringspot virus (PRSV). Overall, we identified 53 aphid species (3,899 individuals), from which the melon aphid, Aphis gossypii Glover, a pumpkin-colonizing species, predominated (76 and 37% of samples in 2010 and 2011, respectively). CMV and ZYMV were not detected, but WMV and PRSV were prevalent, both regionally (WMV: 28/29 fields, PRSV: 21/29 fields) and within fields (infection rates = 69 and 55% for WMV in 2010 and 2011; 28 and 25% for PRSV in 2010 and 2011). However, early-season samples showed extremely low infection levels, suggesting cucurbit viruses are not seed-transmitted and implicating aphid activity as a causal factor driving virus spread. Interestingly, neither noncolonizer and colonizer alightment nor total aphid alightment were good predictors of virus presence, but community analyses revealed species-specific relationships. For example, cowpea aphid (Aphis craccivora Koch) and spotted alfalfa aphid (Therioaphis trifolii Monell f. maculata) were associated with PRSV infection, whereas the oleander aphid (Aphis nerii Bover de Fonscolombe) was associated with WMV spread within fields. These outcomes highlight the need for tailored management plans targeting key vectors of nonpersistent viruses in agricultural systems. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Plant waxy bloom on peas affects infection of pea aphids by Pandora neoaphidis.

    PubMed

    Duetting, Patrick S; Ding, Hongjian; Neufeld, Jeffrey; Eigenbrode, Sanford D

    2003-11-01

    This study examined the effects of the surface wax bloom of pea plants, Pisum sativum, on infection of pea aphids, Acyrthosiphon pisum, by the fungal pathogen Pandora neoaphidis. In prior field surveys, a higher proportion of P. neoaphidis-killed pea aphids (cadavers) had been observed on a pea line with reduced wax bloom, as compared with a sister line with normal surface wax bloom. Laboratory bioassays were conducted in order to examine the mechanisms. After plants of each line infested with aphids were exposed to similar densities of conidia, the rate of accumulation of cadavers on the reduced wax line was significantly greater than on the normal wax bloom line; at the end of the experiment (13d), the proportion of aphid cadavers on the reduced wax line was approximately four times that on the normal wax bloom line. When plants were exposed to conidia first and then infested with aphids, the rate of accumulation of cadavers was slightly but significantly greater on the reduced wax line, and infection at the end of the experiment (16d) did not differ between the lines. When aphids were exposed first and then released onto the plants, no differences in the proportion of aphid cadavers were observed between the pea lines. Greater infection of pea aphid on reduced wax peas appears to depend upon plants being exposed to inoculum while aphids are settled in typical feeding positions on the plant. Additional experiments demonstrated increased adhesion and germination by P. neoaphidis conidia to leaf surfaces of the reduced wax line as compared with normal wax line, and this could help explain the higher infection rate by P. neoaphidis on the reduced wax line. In bioassays using surface waxes extracted from the two lines, there was no effect of wax source on germination of P. neoaphidis conidia.

  17. Response of the aphid parasitoid Aphidius funebris to volatiles from undamaged and aphid-infested Centaurea nigra.

    PubMed

    Pareja, Martín; Moraes, Maria C B; Clark, Suzanne J; Birkett, Michael A; Powell, Wilf

    2007-04-01

    Two issues have hindered the understanding of the ecology and evolution of volatile-mediated tritrophic interactions: few studies have addressed noncrop systems; and few statistical techniques have been applied that are suitable for the analysis of complex volatile blends. In this paper, we addressed both of these issues by studying the noncrop system involving the plant Centaurea nigra, the specialist aphid Uroleucon jaceae, and the parasitoid Aphidius funebris. In a Y-tube olfactometer, A. funebris was attracted to the odor from undamaged C. nigra, but preferred the plant-host complex (PHC) after 3 d of feeding by 200 U. jaceae over the undamaged plant, but not after three or 5 d of feeding by 50 U. jaceae. When aphids were removed, the initial preference for the damaged plant remained, but the final preference was not greater than for the undamaged plant. No qualitative differences were detected between the headspaces of C. nigra and the C. nigra-U. jaceae PHC. For quantitative analysis, we used a compositional approach, which treats each compound produced as part of a blend, and not as a compound released in isolation, thus allowing analysis of the relative contribution of each compound to the blend as a whole. With this approach, subtle increases and decreases of some green leaf volatiles and monoterpenoids on the third day of aphid infestation were detected. Mechanically damaged C. nigra had a volatile profile that differed from undamaged C. nigra and the PHC. One and 10 ng of (Z)-3-hexenyl acetate, and 10 or 100 ng of 6-methyl-5-hepten-2-one were attractive to the parasitoid when placed in solution on filter paper. A. funebris appears to be using a combination of chemical cues to locate host-infested plants.

  18. Large-scale gene discovery in the pea aphid Acyrthosiphon pisum (Hemiptera)

    PubMed Central

    Sabater-Muñoz, Beatriz; Legeai, Fabrice; Rispe, Claude; Bonhomme, Joël; Dearden, Peter; Dossat, Carole; Duclert, Aymeric; Gauthier, Jean-Pierre; Ducray, Danièle Giblot; Hunter, Wayne; Dang, Phat; Kambhampati, Srini; Martinez-Torres, David; Cortes, Teresa; Moya, Andrès; Nakabachi, Atsushi; Philippe, Cathy; Prunier-Leterme, Nathalie; Rahbé, Yvan; Simon, Jean-Christophe; Stern, David L; Wincker, Patrick; Tagu, Denis

    2006-01-01

    Aphids are the leading pests in agricultural crops. A large-scale sequencing of 40,904 ESTs from the pea aphid Acyrthosiphon pisum was carried out to define a catalog of 12,082 unique transcripts. A strong AT bias was found, indicating a compositional shift between Drosophila melanogaster and A. pisum. An in silico profiling analysis characterized 135 transcripts specific to pea-aphid tissues (relating to bacteriocytes and parthenogenetic embryos). This project is the first to address the genetics of the Hemiptera and of a hemimetabolous insect. PMID:16542494

  19. Exploring the nitrogen ingestion of aphids--a new method using electrical penetration graph and (15)N labelling.

    PubMed

    Kuhlmann, Franziska; Opitz, Sebastian E W; Inselsbacher, Erich; Ganeteg, Ulrika; Näsholm, Torgny; Ninkovic, Velemir

    2013-01-01

    Studying plant-aphid interactions is challenging as aphid feeding is a complex process hidden in the plant tissue. Here we propose a combination of two well established methods to study nutrient acquisition by aphids focusing on the uptake of isotopically labelled nitrogen ((15)N). We combined the Electrical Penetration Graph (EPG) technique that allows detailed recording of aphid feeding behaviour and stable isotope ratio mass spectrometry (IRMS) to precisely measure the uptake of nitrogen. Bird cherry-oat aphids Rhopalosiphum padi L. (Hemiptera, Aphididae) fed for 24 h on barley plants (Hordeum vulgare L., cultivar Lina, Poaceae) that were cultivated with a (15)N enriched nutrient solution. The time aphids fed in the phloem was strongly positive correlated with their (15)N uptake. All other single behavioural phases were not correlated with (15)N enrichment in the aphids, which corroborates their classification as non-feeding EPG phases. In addition, phloem-feeding and (15)N enrichment of aphids was divided into two groups. One group spent only short time in the phloem phase and was unsuccessful in nitrogen acquisition, while the other group displayed longer phloem-feeding phases and was successful in nitrogen acquisition. This suggests that several factors such as the right feeding site, time span of feeding and individual conditions play a role for the aphids to acquire nutrients successfully. The power of this combination of methods for studying plant-aphid interactions is discussed.

  20. Exploring the Nitrogen Ingestion of Aphids — A New Method Using Electrical Penetration Graph and 15N Labelling

    PubMed Central

    Kuhlmann, Franziska; Opitz, Sebastian E. W.; Inselsbacher, Erich; Ganeteg, Ulrika; Näsholm, Torgny; Ninkovic, Velemir

    2013-01-01

    Studying plant-aphid interactions is challenging as aphid feeding is a complex process hidden in the plant tissue. Here we propose a combination of two well established methods to study nutrient acquisition by aphids focusing on the uptake of isotopically labelled nitrogen (15N). We combined the Electrical Penetration Graph (EPG) technique that allows detailed recording of aphid feeding behaviour and stable isotope ratio mass spectrometry (IRMS) to precisely measure the uptake of nitrogen. Bird cherry-oat aphids Rhopalosiphum padi L. (Hemiptera, Aphididae) fed for 24 h on barley plants (Hordeum vulgare L., cultivar Lina, Poaceae) that were cultivated with a 15N enriched nutrient solution. The time aphids fed in the phloem was strongly positive correlated with their 15N uptake. All other single behavioural phases were not correlated with 15N enrichment in the aphids, which corroborates their classification as non-feeding EPG phases. In addition, phloem-feeding and 15N enrichment of aphids was divided into two groups. One group spent only short time in the phloem phase and was unsuccessful in nitrogen acquisition, while the other group displayed longer phloem-feeding phases and was successful in nitrogen acquisition. This suggests that several factors such as the right feeding site, time span of feeding and individual conditions play a role for the aphids to acquire nutrients successfully. The power of this combination of methods for studying plant-aphid interactions is discussed. PMID:24376642

  1. Microsatellite and Chromosome Evolution of Parthenogenetic Sitobion Aphids in Australia

    PubMed Central

    Sunnucks, P.; England, P. R.; Taylor, A. C.; Hales, D. F.

    1996-01-01

    Single-locus microsatellite variation correlated perfectly with chromosome number in Sitobion miscanthi aphids. The microsatellites were highly heterozygous, with up to 10 alleles per locus in this species. Despite this considerable allelic variation, only seven different S. miscanthi genotypes were discovered in 555 individuals collected from a wide range of locations, hosts and sampling periods. Relatedness between genotypes suggests only two successful colonizations of Australia. There was no evidence for genetic recombination in 555 S. miscanthi so the occurrence of recent sexual reproduction must be near zero. Thus diversification is by mutation and chromosomal rearrangement alone. Since the aphids showed no sexual recombination, microsatellites can mutate without meiosis. Five of seven microsatellite differences were a single repeat unit, and one larger jump is likely. The minimum numbers of changes between karyotypes corresponded roughly one-to-one with microsatellite allele changes, which suggests very rapid chromosomal evolution. A chromosomal fission occurred in a cultured line, and a previously unknown chromosomal race was detected. All 121 diverse S. near fragariae were heterozygous but revealed only one genotype. This species too must have a low rate of sexual reproduction and few colonizations of Australia. PMID:8889535

  2. Aphid-parasitoid community structure on genetically modified wheat.

    PubMed

    von Burg, Simone; van Veen, Frank J F; Álvarez-Alfageme, Fernando; Romeis, Jörg

    2011-06-23

    Since the introduction of genetically modified (GM) plants, one of the main concerns has been their potential effect on non-target insects. Many studies have looked at GM plant effects on single non-target herbivore species or on simple herbivore-natural enemy food chains. Agro-ecosystems, however, are characterized by numerous insect species which are involved in complex interactions, forming food webs. In this study, we looked at transgenic disease-resistant wheat (Triticum aestivum) and its effect on aphid-parasitoid food webs. We hypothesized that the GM of the wheat lines directly or indirectly affect aphids and that these effects cascade up to change the structure of the associated food webs. Over 2 years, we studied different experimental wheat lines under semi-field conditions. We constructed quantitative food webs to compare their properties on GM lines with the properties on corresponding non-transgenic controls. We found significant effects of the different wheat lines on insect community structure up to the fourth trophic level. However, the observed effects were inconsistent between study years and the variation between wheat varieties was as big as between GM plants and their controls. This suggests that the impact of our powdery mildew-resistant GM wheat plants on food web structure may be negligible and potential ecological effects on non-target insects limited.

  3. Quantifying Russian wheat aphid pest intensity across the Great Plains.

    PubMed

    Merrill, Scott C; Peairs, Frank B

    2012-12-01

    Wheat, the most important cereal crop in the Northern Hemisphere, is at-risk for an approximate 10% reduction in worldwide production because of animal pests. The potential economic impact of cereal crop pests has resulted in substantial research efforts into the understanding of pest agroecosystems and development of pest management strategy. Management strategy is informed frequently by models that describe the population dynamics of important crop pests and because of the economic impact of these pests, many models have been developed. Yet, limited effort has ensued to compare and contrast models for their strategic applicability and quality. One of the most damaging pests of wheat in North America is the Russian wheat aphid, Diuraphis noxia (Kurdjumov). Eighteen D. noxia population dynamic models were developed from the literature to describe pest intensity. The strongest models quantified the negative effects of fall and spring precipitation on aphid intensity, and the positive effects associated with alternate food source availability. Population dynamic models were transformed into spatially explicit models and combined to form a spatially explicit, model-averaged result. Our findings were used to delineate pest intensity on winter wheat across much of the Great Plains and will help improve D. noxia management strategy.

  4. Biotypic diversity in Colorado Russian wheat aphid (Hemiptera: Aphididae) populations.

    PubMed

    Weiland, Aubrey A; Peairs, Frank B; Randolph, Terri L; Rudolph, Jeffrey B; Haley, Scott D; Puterka, Gary J

    2008-04-01

    The biotypic diversity of the Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae), was assessed in five isolates collected in Colorado. Three isolates, RWA 1, RWA 2, and an isolate from Montezuma County, CO, designated RWA 6, were originally collected from cultivated wheat, Triticum aestivum L., and obtained from established colonies at Colorado State University. The fourth isolate, designated RWA 7, was collected from Canada wildrye, Elymus canadensis L., in Baca County, CO. The fifth isolate, designated RWA 8, was collected from crested wheatgrass, Agropyron cristatum (L.) Gaertn., in Montezuma County, CO. The four isolates were characterized in a standard seedling assay, by using 24 plant differentials, 22 wheat lines and two barley, Hordeum vulgare L., lines. RWA 1 was the least virulent of the isolates, killing only the four susceptible entries. RWA 8 also killed only the four susceptible entries, but it expressed intermediate virulence on seven wheat lines. RWA 6, killing nine entries, and RWA 7, killing 11 entries, both expressed an intermediate level of virulence overall, but differed in their level of virulence to 'CO03797' (Dn1), 'Yumar' (Dn4), and 'CO960293-2'. RWA 2 was the most virulent isolate, killing 14 entries, including Dn4- and Dny-containing wheat. Four wheat lines, '94M370' (Dn7), 'STARS 02RWA2414-11', CO03797, and 'CI2401', were resistant to the five isolates. The results of this screening confirm the presence of five unique Russian wheat aphid biotypes in Colorado.

  5. Cyclical parthenogenesis and viviparity in aphids as evolutionary novelties.

    PubMed

    Davis, Gregory K

    2012-09-01

    Evolutionary novelties represent challenges to biologists, particularly those who would like to understand the developmental and genetic changes responsible for their appearance. Most modern aphids possess two apparent evolutionary novelties: cyclical parthenogenesis (a life cycle with both sexual and asexual phases) and viviparity (internal development and live birth of progeny) in their asexual phase. Here I discuss the evolution of these apparent novelties from a developmental standpoint. Although a full understanding of the evolution of cyclical parthenogenesis and viviparity in aphids can seem a daunting task, these complex transitions can at least be broken down into a handful of steps. I argue that these should include the following: a differentiation of two developmentally distinct oocytes; de novo synthesis of centrosomes and modification of meiosis during asexual oogenesis; a loss or bypass of any cell cycle arrest and changes in key developmental events during viviparous oogenesis; and a change in how mothers specify the sexual vs. asexual fates of their progeny. Grappling with the nature of such steps and the order in which they occurred ought to increase our understanding and reduce the apparent novelty of complex evolutionary transitions.

  6. Plant-derived differences in the composition of aphid honeydew and their effects on colonies of aphid-tending ants

    PubMed Central

    Pringle, Elizabeth G; Novo, Alexandria; Ableson, Ian; Barbehenn, Raymond V; Vannette, Rachel L

    2014-01-01

    In plant–ant–hemipteran interactions, ants visit plants to consume the honeydew produced by phloem-feeding hemipterans. If genetically based differences in plant phloem chemistry change the chemical composition of hemipteran honeydew, then the plant's genetic constitution could have indirect effects on ants via the hemipterans. If such effects change ant behavior, they could feed back to affect the plant itself. We compared the chemical composition of honeydews produced by Aphis nerii aphid clones on two milkweed congeners, Asclepias curassavica and Asclepias incarnata, and we measured the responses of experimental Linepithema humile ant colonies to these honeydews. The compositions of secondary metabolites, sugars, and amino acids differed significantly in the honeydews from the two plant species. Ant colonies feeding on honeydew derived from A. incarnata recruited in higher numbers to artificial diet, maintained higher queen and worker dry weight, and sustained marginally more workers than ants feeding on honeydew derived from A. curassavica. Ants feeding on honeydew from A. incarnata were also more exploratory in behavioral assays than ants feeding from A. curassavica. Despite performing better when feeding on the A. incarnata honeydew, ant workers marginally preferred honeydew from A. curassavica to honeydew from A. incarnata when given a choice. Our results demonstrate that plant congeners can exert strong indirect effects on ant colonies by means of plant-species-specific differences in aphid honeydew chemistry. Moreover, these effects changed ant behavior and thus could feed back to affect plant performance in the field. PMID:25505534

  7. Plant-derived differences in the composition of aphid honeydew and their effects on colonies of aphid-tending ants.

    PubMed

    Pringle, Elizabeth G; Novo, Alexandria; Ableson, Ian; Barbehenn, Raymond V; Vannette, Rachel L

    2014-11-01

    In plant-ant-hemipteran interactions, ants visit plants to consume the honeydew produced by phloem-feeding hemipterans. If genetically based differences in plant phloem chemistry change the chemical composition of hemipteran honeydew, then the plant's genetic constitution could have indirect effects on ants via the hemipterans. If such effects change ant behavior, they could feed back to affect the plant itself. We compared the chemical composition of honeydews produced by Aphis nerii aphid clones on two milkweed congeners, Asclepias curassavica and Asclepias incarnata, and we measured the responses of experimental Linepithema humile ant colonies to these honeydews. The compositions of secondary metabolites, sugars, and amino acids differed significantly in the honeydews from the two plant species. Ant colonies feeding on honeydew derived from A. incarnata recruited in higher numbers to artificial diet, maintained higher queen and worker dry weight, and sustained marginally more workers than ants feeding on honeydew derived from A. curassavica. Ants feeding on honeydew from A. incarnata were also more exploratory in behavioral assays than ants feeding from A. curassavica. Despite performing better when feeding on the A. incarnata honeydew, ant workers marginally preferred honeydew from A. curassavica to honeydew from A. incarnata when given a choice. Our results demonstrate that plant congeners can exert strong indirect effects on ant colonies by means of plant-species-specific differences in aphid honeydew chemistry. Moreover, these effects changed ant behavior and thus could feed back to affect plant performance in the field.

  8. All 37 Mitochondrial Genes of Aphid Aphis craccivora Obtained from Transcriptome Sequencing: Implications for the Evolution of Aphids

    PubMed Central

    Li, Hu; Cai, Wanzhi

    2016-01-01

    The availability of mitochondrial genome data for Aphididae, one of the economically important insect pest families, in public databases is limited. The advent of next generation sequencing technology provides the potential to generate mitochondrial genome data for many species timely and cost-effectively. In this report, we used transcriptome sequencing technology to determine all the 37 mitochondrial genes of the cowpea aphid, Aphis craccivora. This method avoids the necessity of finding suitable primers for long PCRs or primer-walking amplicons, and is proved to be effective in obtaining the whole set of mitochondrial gene data for insects with difficulty in sequencing mitochondrial genome by PCR-based strategies. Phylogenetic analyses of aphid mitochondrial genome data show clustering based on tribe level, and strongly support the monophyly of the family Aphididae. Within the monophyletic Aphidini, three samples from Aphis grouped together. In another major clade of Aphididae, Pterocomma pilosum was recovered as a potential sister-group of Cavariella salicicola, as part of Macrosiphini. PMID:27314587

  9. Fungal plant endosymbionts alter life history and reproductive success of aphid predators

    PubMed Central

    de Sassi, Claudio; Müller, Christine B; Krauss, Jochen

    2006-01-01

    Endosymbionts occur in most plant species and may affect interactions among herbivores and their predators through the production of toxic alkaloids. Here, we ask whether effects of mycotoxins produced by the symbiosis of the fungal endophyte Neotyphodium lolii and the grass Lolium perenne are transmitted to the aphidophagous ladybird Coccinella septempunctata when feeding on cereal aphids Rhopalosiphum padi on infected plants. The larval development of coccinellids was extended, while their survival was reduced when feeding exclusively on aphids from infected plants. Ladybirds developing on aphids from infected plants showed reduced fecundity and impaired reproductive performance. Body size and symmetries of ladybird adults were not affected by the endophytes. Consistently strong, negative effects of endophytes on the lifetime performance of ladybirds indicates that mycotoxins are transmitted along food chains, causing significant damage for top predators. Such cascading effects will influence the population dynamics of aphid predators in the long term and could feedback to the primary plant producers. PMID:16720406

  10. The defensive aphid symbiont Hamiltonella defensa affects host quality differently for Aphelinus glycinis versus Aphelinus atriplicis

    USDA-ARS?s Scientific Manuscript database

    Endosymbiont interactions with hosts have important affects on fitness, including the fitness of many pest and beneficial species. Among these interactions, facultative endosymbiotic bacteria can protect aphid species from parasitoids. APHIS CRACCIVORA and ACYRTHOSIPHON PISUM harbor the symbiotic ...

  11. Application of plant growth regulators mitigates chlorotic foliar injury by the black pecan aphid (Hemiptera: Aphididae)

    USDA-ARS?s Scientific Manuscript database

    Chlorotic feeding injury by the black pecan aphid, Melanocallis caryaefoliae (Davis) (Hemiptera: Aphididae), to pecan (Carya illinoinensis [Wangenh.] K. Koch) foliage can result in leaf senescence and abscission. The plant growth regulators chlorforfenuron (CPPU), gibberellic acid (GA3) and aminoet...

  12. The impact of clonal mixing on the evolution of social behaviour in aphids.

    PubMed

    Bryden, John; Jansen, Vincent A A

    2010-06-07

    Reports of substantial clonal mixing measured in social aphid colonies seem, on the face of it, to rule out population structure as an explanation of this enigmatic insect's social behaviour. To clarify how selection operates in aphids, and to disentangle direct and indirect fitness components, we present a model of the life cycle of a typical colony-dwelling aphid. The model incorporates ecological factors and includes a trade-off between investing in social behaviour and investing in reproduction. Our focus on inclusive fitness contrasts with previous approaches that optimize colony output. Through deriving a variant of Hamilton's rule, we show that a simple relationship can be established between the patch-carrying capacity and immigration rates into patches. Our results indicate that the levels of clonal mixing reported are not inconsistent with social behaviour. We discuss our model in terms of the evolutionary origins of social behaviour in aphids.

  13. Fungal plant endosymbionts alter life history and reproductive success of aphid predators.

    PubMed

    de Sassi, Claudio; Müller, Christine B; Krauss, Jochen

    2006-05-22

    Endosymbionts occur in most plant species and may affect interactions among herbivores and their predators through the production of toxic alkaloids. Here, we ask whether effects of mycotoxins produced by the symbiosis of the fungal endophyte Neotyphodium lolii and the grass Lolium perenne are transmitted to the aphidophagous ladybird Coccinella septempunctata when feeding on cereal aphids Rhopalosiphum padi on infected plants. The larval development of coccinellids was extended, while their survival was reduced when feeding exclusively on aphids from infected plants. Ladybirds developing on aphids from infected plants showed reduced fecundity and impaired reproductive performance. Body size and symmetries of ladybird adults were not affected by the endophytes. Consistently strong, negative effects of endophytes on the lifetime performance of ladybirds indicates that mycotoxins are transmitted along food chains, causing significant damage for top predators. Such cascading effects will influence the population dynamics of aphid predators in the long term and could feedback to the primary plant producers.

  14. Field keys to predators of the balsam woolly aphid in North Carolina

    Treesearch

    Gene D. Amman

    1970-01-01

    These keys will be useful for field identification of immature insect, adult mite, and slug predators of the balsam woolly aphid. The keys include, in addition to native predators, the larvae of three species introduced to North Carolina.

  15. Host foraging for differentially adapted brassica-feeding aphids by the braconid parasitoid Diaeretiella rapae.

    PubMed

    Blande, James D; Pickett, John A; Poppy, Guy M

    2008-08-01

    Interactions occurring in a tritrophic system comprising plants, aphids and parasitoids are of great complexity. The generalist endoparasitoid Diaeretiella rapae (McIntosh) (Hymenoptera: Aphidiidae) displays specialist characteristics on brassica feeding aphids. Previously, we studied differential signalling to D. rapae by specialist and generalist Brassicaceae feeding aphids on turnip. We reported no differences in the attractiveness of volatile compounds from the two turnip/aphid complexes. However, we reported a significantly greater D. rapae attack rate on the specialist Lipaphis erysimi (Kaltenbach) than the generalist Myzus persicae (Sulzer). As a consequence we predicted that D. rapae would forage more efficiently and produce more offspring on L. erysimi. We present here some additional data collected in a more complex spatial/temporal environment in large experimental chambers and discuss this, drawing attention to the need for careful interpretation of mechanistic information in predicting the overall foraging process.

  16. Toxicity of biorational insecticides: activity against the green peach aphid, Myzus persicae (Sulzer).

    PubMed

    Edelson, Jonathan V; Duthie, J; Roberts, W

    2002-03-01

    The relationship between dose for each of four biorational insecticides (pyrethrins, neem extract, capsiacin extract, insecticidal soap) and mortality of the green peach aphid (Myzus persicae) was determined using a laboratory bioassay. These insecticides were toxic to aphids and paired mixtures of the insecticides provided synergistic activity as measured by aphid mortality under the laboratory bioassay conditions. Capsiacin extracts were found to provide low levels of mortality alone but acted synergistically in mixtures with the other insecticides and provided higher than expected levels of mortality. Activity as determined in the laboratory for each insecticide was not evident under field-use conditions in five separate experiments. Under field conditions and using common application methods, these insecticides did not provide significant levels of control of aphids.

  17. Variable effects of fungal endophyte-infected grasses on the performance of pestiferous aphids

    USDA-ARS?s Scientific Manuscript database

    The extent of fungal endophyte (Neotyphodium) based antibiosis resistance in temperate grasses (Lolium spp., Hordeum spp.) to five pestiferous aphid species (Rhopalosiphum padi (L.), Diuraphis noxia (Kurdjumov), Schizaphis graminum (Rondani), Metopolophium dirhodum (Walker), Aploneura lentisci (Pass...

  18. Factors limiting the spread of the protective symbiont HAMILTONELLA DEFENSA in the aphid APHIS CRACCIVORA

    USDA-ARS?s Scientific Manuscript database

    Many insects are associated with heritable facultative symbionts that mediate important ecological interactions, including host protection against natural enemies. Despite such benefits, facultative symbionts are commonly found at intermediate frequencies in surveyed populations. The cowpea aphid,...

  19. Response of the entomopathogenic fungus Pandora neoaphidis to aphid-induced plant volatiles.

    PubMed

    Baverstock, J; Elliot, S L; Alderson, P G; Pell, J K

    2005-06-01

    We used a model plant-aphid system to investigate whether the aphid-specific entomopathogenic fungus Pandora neoaphidis responds to aphid-induced defence by the broad-bean plant, Vicia faba. Laboratory experiments indicated that neither in vivo sporulation, conidia size nor the in vitro growth of P. neoaphidis was affected by Acyrthosiphon pisum-induced V. faba volatiles. The proportion of conidia germinating on A. pisum feeding on previously damaged plants was significantly greater than on aphids feeding on undamaged plants, suggesting a direct functional effect of the plant volatiles on the fungus. However, there were no significant differences in the infectivity of P. neoaphidis towards A. pisum feeding on either undamaged V. faba plants or plants previously infested with A. pisum. Therefore, these results provide no evidence to suggest that P. neoaphidis contributes to plant indirect defence strategies.

  20. Tracking the global dispersal of a cosmopolitan insect pest, the peach potato aphid

    PubMed Central

    Margaritopoulos, John T; Kasprowicz, Louise; Malloch, Gaynor L; Fenton, Brian

    2009-01-01

    Background Global commerce and human transportation are responsible for the range expansion of various insect pests such as the plant sucking aphids. High resolution DNA markers provide the opportunity to examine the genetic structure of aphid populations, identify aphid genotypes and infer their evolutionary history and routes of expansion which is of value in developing management strategies. One of the most widespread aphid species is the peach-potato aphid Myzus persicae, which is considered as a serious pest on various crops in many parts of the world. The present study examined the genetic variation of this aphid at a world scale and then related this to distribution patterns. In particular, 197 aphid parthenogenetic lineages from around the world were analysed with six microsatellite loci. Results Bayesian clustering and admixture analysis split the aphid genotypes into three genetic clusters: European M. persicae persicae, New Zealand M. persicae persicae and Global M. persicae nicotianae. This partition was supported by FST and genetic distance analyses. The results showed two further points, a possible connection between genotypes found in the UK and New Zealand and globalization of nicotianae associated with colonisation of regions where tobacco is not cultivated. In addition, we report the presence of geographically widespread clones and for the first time the presence of a nicotianae genotype in the Old and New World. Lastly, heterozygote deficiency was detected in some sexual and asexual populations. Conclusion The study revealed important genetic variation among the aphid populations we examined and this was partitioned according to region and host-plant. Clonal selection and gene flow between sexual and asexual lineages are important factors shaping the genetic structure of the aphid populations. In addition, the results reflected the globalization of two subspecies of M. persicae with successful clones being spread at various scales throughout the

  1. Comparative transcriptome analysis of Gossypium hirsutum L. in response to sap sucking insects: aphid and whitefly

    PubMed Central

    2013-01-01

    Background Cotton (Gossypium hirsutum L.) is a major fiber crop that is grown worldwide; it faces extensive damage from sap-sucking insects, including aphids and whiteflies. Genome-wide transcriptome analysis was performed to understand the molecular details of interaction between Gossypium hirsutum L. and sap-sucking pests, namely Aphis gossypii (Aphid) and Bemisia tabacci (Whiteflies). Roche’s GS-Titanium was used to sequence transcriptomes of cotton infested with aphids and whiteflies for 2 h and 24 h. Results A total of 100935 contigs were produced with an average length of 529 bp after an assembly in all five selected conditions. The Blastn of the non-redundant (nr) cotton EST database resulted in the identification of 580 novel contigs in the cotton plant. It should be noted that in spite of minimal physical damage caused by the sap-sucking insects, they can change the gene expression of plants in 2 h of infestation; further change in gene expression due to whiteflies is quicker than due to aphids. The impact of the whitefly 24 h after infestation was more or less similar to that of the aphid 2 h after infestation. Aphids and whiteflies affect many genes that are regulated by various phytohormones and in response to microbial infection, indicating the involvement of complex crosstalk between these pathways. The KOBAS analysis of differentially regulated transcripts in response to aphids and whiteflies indicated that both the insects induce the metabolism of amino acids biosynthesis specially in case of whiteflies infestation at later phase. Further we also observed that expression of transcript related to photosynthesis specially carbon fixation were significantly influenced by infestation of Aphids and Whiteflies. Conclusions A comparison of different transcriptomes leads to the identification of differentially and temporally regulated transcripts in response to infestation by aphids and whiteflies. Most of these differentially expressed contigs were

  2. A Trio of Viral Proteins Tunes Aphid-Plant Interactions in Arabidopsis thaliana

    PubMed Central

    Du, Zhiyou; Murphy, Alex M.; Anggoro, Damar Tri; Tungadi, Trisna; Luang-In, Vijitra; Lewsey, Mathew G.; Rossiter, John T.; Powell, Glen; Smith, Alison G.; Carr, John P.

    2013-01-01

    Background Virus-induced deterrence to aphid feeding is believed to promote plant virus transmission by encouraging migration of virus-bearing insects away from infected plants. We investigated the effects of infection by an aphid-transmitted virus, cucumber mosaic virus (CMV), on the interaction of Arabidopsis thaliana, one of the natural hosts for CMV, with Myzus persicae (common names: ‘peach-potato aphid’, ‘green peach aphid’). Methodology/Principal Findings Infection of Arabidopsis (ecotype Col-0) with CMV strain Fny (Fny-CMV) induced biosynthesis of the aphid feeding-deterrent 4-methoxy-indol-3-yl-methylglucosinolate (4MI3M). 4MI3M inhibited phloem ingestion by aphids and consequently discouraged aphid settling. The CMV 2b protein is a suppressor of antiviral RNA silencing, which has previously been implicated in altering plant-aphid interactions. Its presence in infected hosts enhances the accumulation of CMV and the other four viral proteins. Another viral gene product, the 2a protein (an RNA-dependent RNA polymerase), triggers defensive signaling, leading to increased 4MI3M accumulation. The 2b protein can inhibit ARGONAUTE1 (AGO1), a host factor that both positively-regulates 4MI3M biosynthesis and negatively-regulates accumulation of substance(s) toxic to aphids. However, the 1a replicase protein moderated 2b-mediated inhibition of AGO1, ensuring that aphids were deterred from feeding but not poisoned. The LS strain of CMV did not induce feeding deterrence in Arabidopsis ecotype Col-0. Conclusions/Significance Inhibition of AGO1 by the 2b protein could act as a booby trap since this will trigger antibiosis against aphids. However, for Fny-CMV the interplay of three viral proteins (1a, 2a and 2b) appears to balance the need of the virus to inhibit antiviral silencing, while inducing a mild resistance (antixenosis) that is thought to promote transmission. The strain-specific effects of CMV on Arabidopsis-aphid interactions, and differences between

  3. Arabidopsis thaliana—Myzus persicae interaction: shaping the understanding of plant defense against phloem-feeding aphids

    PubMed Central

    Louis, Joe; Shah, Jyoti

    2013-01-01

    The phloem provides a unique niche for several organisms. Aphids are a large group of Hemipteran insects that utilize stylets present in their mouthparts to pierce sieve elements and drink large volumes of phloem sap. In addition, many aphids also vector viral diseases. Myzus persicae, commonly known as the green peach aphid (GPA), is an important pest of a large variety of plants that includes Arabidopsis thaliana. This review summarizes recent studies that have exploited the compatible interaction between Arabidopsis and GPA to understand the molecular and physiological mechanisms utilized by plants to control aphid infestation, as well as genes and mechanisms that contribute to susceptibility. In addition, recent efforts to identify aphid-delivered elicitors of plant defenses and novel aphid salivary components that facilitate infestation are also discussed. PMID:23847627

  4. Distribution and diversity of Russian wheat aphid (Hemiptera: Aphididae) biotypes in South Africa and Lesotho.

    PubMed

    Jankielsohn, Astrid

    2011-10-01

    Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae) was recorded for the first time in South Africa in 1978. In 2005, a second biotype, RWASA2, emerged, and here we report on the emergence of yet another biotype, found for the first time in 2009. The discovery of new Russian wheat aphid biotypes is a significant challenge to the wheat, Triticum aestivum L., industry in South Africa. Russian wheat aphid resistance in wheat, that offered wheat producers a long-term solution to Russian wheat aphid control, may no longer be effective in areas where the new biotypes occur. It is therefore critical to determine the diversity and extent of distribution of biotypes in South Africa to successfully deploy Russian wheat aphid resistance in wheat. Screening of 96 Russian wheat aphid clones resulted in identification of three Russian wheat aphid biotypes. Infestations of RWASA1 caused susceptible damage symptoms only in wheat entries containing the Dn3 gene. Infestations of RWASA2 caused susceptible damage symptoms in wheat entries containing Dn1, Dn2, Dn3, and Dn9 resistant genes. Based on the damage-rating scores for the seven resistance sources, a new biotype, which caused damage rating scores different from those for RWASA1 and RWASA2, was evident among the Russian wheat aphid populations tested. This new biotype is virulent to the same resistance sources as RWASA2 (Dn1, Dn2, Dn3, and Dn9), but it also has added virulence to Dn4, whereas RWASA2 is avirulent to this resistance source.

  5. Response of Russian wheat aphid resistance in wheat and barley to four Diuraphis (Hemiptera: Aphididae) species.

    PubMed

    Puterka, Gary J; Scott, J Nicholson; Brown, Michael J; Hammon, R W

    2013-04-01

    Three Diuraphis species, Diuraphis frequens (Walker), Diuraphis mexicana (McVicar Baker), and Diuraphis tritici (Gillette), were known to exist in the United States before the 1986 appearance of the Russian wheat aphid, Diuraphis noxia Kurdjumov. The Russian wheat aphid soon became a significant pest of wheat although other endemic Diuraphis species were known to infest wheat. Wheat and barley entries resistant and susceptible to Russian wheat aphid biotype 2 were evaluated against all four Diuraphis species to determine their host interrelationships. Leaf chlorosis, leaf roll, leaf number, plant height, and infestation levels were assessed 21 d after the plants were infested by aphids in a no-choice caged environment. D. mexicana was unable to survive on wheat by 21 d after infestation and effects on the plant damage variables were negligible. D. frequens survived at low levels on resistant and susceptible plant entries and had a low impact on plant damage and growth. Russian wheat aphid biotype 2 and D. tritici were damaged most wheat and barley lines except the Russian wheat aphid biotype 2-resistant wheat lines containing genes from Dn7, STARS 2414-11, and CI2401; and resistant barley containing genes from STARS 9577B and 9301B. Russian wheat aphid biotype 2 and D. tritici reduced the growth of resistant plants by 25-50% and susceptible entries by 65-75%. Reductions at this level are typical under no-choice studies but resistant cultivars do not have these reductions under field conditions. The Russian wheat aphid biotype 2 resistant wheat lines would be effective in managing both wheat pest species.

  6. Transmission biology of Raspberry latent virus, the first aphid-borne reovirus.

    PubMed

    Quito-Avila, Diego F; Lightle, Danielle; Lee, Jana; Martin, Robert R

    2012-05-01

    Raspberry latent virus (RpLV) is a newly characterized reovirus found in commercial raspberry fields in the Pacific Northwest (PNW). Thus far, all members of the plant reoviruses are transmitted in a replicative, persistent manner by several species of leafhoppers or planthoppers. After several failed attempts to transmit RpLV using leafhoppers, the large raspberry aphid, commonly found in the PNW, was tested as a vector of the virus. The virus was transmitted to new, healthy raspberry plants when inoculated with groups of at least 50 viruliferous aphids, suggesting that aphids are vectors of RpLV, albeit inefficient ones. Using absolute and relative quantification methods, it was shown that the virus titer in aphids continued to increase after the acquisition period even when aphids were serially transferred onto fresh, healthy plants on a daily basis. Transmission experiments determined that RpLV has a 6-day latent period in the aphid before it becomes transmissible; however, it was not transmitted transovarially to the next generation. To our knowledge, this is the first report of a plant reovirus transmitted by an aphid. Phylogenetic analyses showed that RpLV is related most closely to but distinct from Rice ragged stunt virus (RRSV), the type member of the genus Oryzavirus. Moreover, the conserved nucleotide termini of the genomic segments of RpLV did not match those of RRSV or other plant reoviruses, allowing us to suggest that RpLV is probably the type member of a new genus in the Reoviridae comprising aphid-transmitted reoviruses.

  7. Evidence for Compensatory Photosynthetic and Yield Response of Soybeans to Aphid Herbivory.

    PubMed

    Kucharik, Christopher J; Mork, Amelia C; Meehan, Timothy D; Serbin, Shawn P; Singh, Aditya; Townsend, Philip A; Stack Whitney, Kaitlin; Gratton, Claudio

    2016-04-13

    The soybean aphid,Aphis glycinesMatsumura, an exotic species in North America that has been detected in 21 U.S. states and Canada, is a major pest for soybean that can reduce maximum photosynthetic capacity and yields. Our existing knowledge is based on relatively few studies that do not span a wide variety of environmental conditions, and often focus on relatively high and damaging population pressure. We examined the effects of varied populations and duration of soybean aphids on soybean photosynthetic rates and yield in two experiments. In a 2011 field study, we found that plants with low cumulative aphid days (CAD, less than 2,300) had higher yields than plants not experiencing significant aphid pressure, suggesting a compensatory growth response to low aphid pressure. This response did not hold at higher CAD, and yields declined. In a 2013 controlled-environment greenhouse study, soybean plants were well-watered and fertilized with nitrogen (N), and aphid populations were manipulated to reach moderate to high levels (8,000-50,000 CAD). Plants tolerated these population levels when aphids were introduced during the vegetative or reproductive phenological stages of the plant, showing no significant reduction in yield. Leaf N concentration and CAD were positively and significantly correlated with increasing ambient photosynthetic rates. Our findings suggest that, given the right environmental conditions, modern soybean plants can withstand higher aphid pressure than previously assumed. Moreover, soybean plants also responded positively through a compensatory photosynthetic effect to moderate population pressure, contributing to stable or increased yield.

  8. Water Stress and Aphid Feeding Differentially Influence Metabolite Composition in Arabidopsis thaliana (L.)

    PubMed Central

    Mewis, Inga; Khan, Mohammed A. M.; Glawischnig, Erich; Schreiner, Monika; Ulrichs, Christian

    2012-01-01

    Little is known about how drought stress influences plant secondary metabolite accumulation and how this affects plant defense against different aphids. We therefore cultivated Arabidopsis thaliana (L.) plants under well-watered, drought, and water-logged conditions. Two aphid species were selected for this study: the generalist Myzus persicae (Sulzer) and the crucifer specialist Brevicoryne brassicae (L.). Metabolite concentrations in the phloem sap, which influence aphid growth, changed particularly under drought stress. Levels of sucrose and several amino acids, such as glutamic acid, proline, isoleucine, and lysine increased, while concentrations of 4-methoxyindol-3-ylmethyl glucosinolate decreased. M. persicae population growth was highest on plants under drought stress conditions. However, B. brassicae did not profit from improved phloem sap quality under drought stress and performed equally in all water treatments. Water stress and aphids generally had an opposite effect on the accumulation of secondary metabolites in the plant rosettes. Drought stress and water-logging led to increased aliphatic glucosinolate and flavonoid levels. Conversely, aphid feeding, especially of M. persicae, reduced levels of flavonoids and glucosinolates in the plants. Correspondingly, transcript levels of aliphatic biosynthetic genes decreased after feeding of both aphid species. Contrary to M. persicae, drought stress did not promote population growth of B. brassicae on these plants. The specialist aphid induced expression of CYP79B2, CYP79B3, and PAD3 with corresponding accumulation of indolyl glucosinolates and camalexin. This was distinct from M. persicae, which did not elicit similarly strong camalexin accumulation, which led to the hypothesis of a specific defense adaptations against the specialist aphid. PMID:23144921

  9. First record of the adventive oriental aphid Schizaphis piricola (Matsumura, 1917) (Hemiptera, Aphididae) in Europe.

    PubMed

    Nicolás, Pérez Hidalgo; Angel, Umaran; M Pilar, Mier Durante

    2011-04-11

    The oriental aphid Schizaphis piricola (Matsumura) is recorded for the first time in Europe, on the ornamental pear tree Pyrus calleryana in landscaped areas in Madrid (Spain). Data on the morphology of the forms on primary host (apterous and alate fundatrigeniae and fundatrices), and their biology and distribution are given. The keys for identifying species of Schizaphis (Schizaphis) in the Iberian Peninsula are updated. Two species of aphids are also recorded for the first time on Pyrus calleryana: Schizaphis piricola and Aphis pomi.

  10. Specificity of Multi-Modal Aphid Defenses against Two Rival Parasitoids

    PubMed Central

    Martinez, Adam J.; Kim, Kyungsun L.; Harmon, Jason P.; Oliver, Kerry M.

    2016-01-01

    Insects are often attacked by multiple natural enemies, imposing dynamic selective pressures for the development and maintenance of enemy-specific resistance. Pea aphids (Acyrthosiphon pisum) have emerged as models for the study of variation in resistance against natural enemies, including parasitoid wasps. Internal defenses against their most common parasitoid wasp, Aphidius ervi, are sourced through two known mechanisms– 1) endogenously encoded resistance or 2) infection with the heritable bacterial symbiont, Hamiltonella defensa. Levels of resistance can range from nearly 0–100% against A. ervi but varies based on aphid genotype and the strain of toxin-encoding bacteriophage (called APSE) carried by Hamiltonella. Previously, other parasitoid wasps were found to commonly attack this host, but North American introductions of A. ervi have apparently displaced all other parasitoids except Praon pequodorum, a related aphidiine braconid wasp, which is still found attacking this host in natural populations. To explain P. pequodorum’s persistence, multiple studies have compared direct competition between both wasps, but have not examined specificity of host defenses as an indirectly mediating factor. Using an array of experimental aphid lines, we first examined whether aphid defenses varied in effectiveness toward either wasp species. Expectedly, both types of aphid defenses were effective against A. ervi, but unexpectedly, were completely ineffective against P. pequodorum. Further examination showed that P. pequodorum wasps suffered no consistent fitness costs from developing in even highly ‘resistant’ aphids. Comparison of both wasps’ egg-larval development revealed that P. pequodorum’s eggs have thicker chorions and hatch two days later than A. ervi’s, likely explaining their differing abilities to overcome aphid defenses. Overall, our results indicate that aphids resistant to A. ervi may serve as reservoirs for P. pequodorum, hence contributing to

  11. Evidence for compensatory photosynthetic and yield response of soybeans to aphid herbivory

    DOE PAGES

    Kucharik, Christopher J.; Mork, Amelia C.; Meehan, Timothy D.; ...

    2016-04-13

    The soybean aphid, Aphis glycines Matsumura, an exotic species in North America that has been detected in 21 U.S. states and Canada, is a major pest for soybean that can reduce maximum photosynthetic capacity and yields. Our existing knowledge is based on relatively few studies that do not span a wide variety of environmental conditions, and often focus on relatively high and damaging population pressure. We examined the effects of varied populations and duration of soybean aphids on soybean photosynthetic rates and yield in two experiments. In a 2011 field study, we found that plants with low cumulative aphid daysmore » (CAD, less than 2,300) had higher yields than plants not experiencing significant aphid pressure, suggesting a compensatory growth response to low aphid pressure. This response did not hold at higher CAD, and yields declined. In a 2013 controlled-environment greenhouse study, soybean plants were well-watered and fertilized with nitrogen (N), and aphid populations were manipulated to reach moderate to high levels (8,000–50,000 CAD). Plants tolerated these population levels when aphids were introduced during the vegetative or reproductive phenological stages of the plant, showing no significant reduction in yield. Leaf N concentration and CAD were positively and significantly correlated with increasing ambient photosynthetic rates. Our findings suggest that, given the right environmental conditions, modern soybean plants can withstand higher aphid pressure than previously assumed. Moreover, soybean plants also responded positively through a compensatory photosynthetic effect to moderate population pressure, contributing to stable or increased yield.« less

  12. Evidence for compensatory photosynthetic and yield response of soybeans to aphid herbivory

    SciTech Connect

    Kucharik, Christopher J.; Mork, Amelia C.; Meehan, Timothy D.; Serbin, Shawn P.; Singh, Aditya; Townsend, Philip A.; Whitney, Kaitlin Stack; Gratton, Claudio

    2016-04-13

    The soybean aphid, Aphis glycines Matsumura, an exotic species in North America that has been detected in 21 U.S. states and Canada, is a major pest for soybean that can reduce maximum photosynthetic capacity and yields. Our existing knowledge is based on relatively few studies that do not span a wide variety of environmental conditions, and often focus on relatively high and damaging population pressure. We examined the effects of varied populations and duration of soybean aphids on soybean photosynthetic rates and yield in two experiments. In a 2011 field study, we found that plants with low cumulative aphid days (CAD, less than 2,300) had higher yields than plants not experiencing significant aphid pressure, suggesting a compensatory growth response to low aphid pressure. This response did not hold at higher CAD, and yields declined. In a 2013 controlled-environment greenhouse study, soybean plants were well-watered and fertilized with nitrogen (N), and aphid populations were manipulated to reach moderate to high levels (8,000–50,000 CAD). Plants tolerated these population levels when aphids were introduced during the vegetative or reproductive phenological stages of the plant, showing no significant reduction in yield. Leaf N concentration and CAD were positively and significantly correlated with increasing ambient photosynthetic rates. Our findings suggest that, given the right environmental conditions, modern soybean plants can withstand higher aphid pressure than previously assumed. Moreover, soybean plants also responded positively through a compensatory photosynthetic effect to moderate population pressure, contributing to stable or increased yield.

  13. Cucumber Plants Baited with Methyl Salicylate Accelerates Scymnus (Pullus) sodalis (Coleoptera: Coccinellidae) Visiting to Reduce Cotton Aphid (Hemiptera: Aphididae) Infestation.

    PubMed

    Dong, Y J; Hwang, S Y

    2017-09-06

    The cotton aphid, Aphis gossypii (Glover) (Hemiptera: Aphididae), is a major pest of many crops worldwide and a major cucumber plant pest in Taiwan. Because cotton aphids rapidly develop insecticide resistance and because of the insecticide residue problem, a safe and sustainable method is required to replace conventional chemical control methods. Methyl salicylate (MeSA), a herbivore-induced plant volatile, has been shown to affect aphids' behavior and attract the natural enemies of aphids for reducing their population. Therefore, this study examined the direct effects of MeSA on cotton aphids' settling preference, population development, and attractiveness to natural enemies. The efficiency of using MeSA and the commercial insecticide pymetrozine for reducing the cotton aphid population in laboratory and outdoor cucumber plant pot was also examined. The results showed no difference in winged aphids' settling preference and population development between the MeSA and blank treatments. Cucumber plants infested with cotton aphids and baited with 0.1% or 10% MeSA contained significantly higher numbers of the natural enemy of cotton aphids, namely Scymnus (Pullus) sodalis (Weise) (Coleoptera: Coccinellidae), and MeSA-treated cucumber plants contained a lower number of aphids. Significantly lower cotton aphid numbers were found on cucumber plants within a 10-m range of MeSA application. In addition, fruit yield showed no difference between the MeSA and pymetrozine treatments. According to our findings, 0.1% MeSA application can replace insecticides as a cotton aphid control tool. However, large-scale experiments are necessary to confirm its efficiency and related conservation biological control strategies before further use. © The Author 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Virulence of Verticillium lecanii (Z.) against cereal aphids; does timing of infection affect the performance of parasitoids and predators?

    PubMed

    Aqueel, Muhammad A; Leather, Simon R

    2013-04-01

    Entomopathogenic fungi such as Verticillium lecanii (Z.) (Mycotal(®)) are used for pest control as an alternative to chemical control. In this study, the effect of V. lecanii on cereal aphids is assessed. In addition, an investigation is carried out to determine whether the use of V. lecanii affects the performance of two natural enemies of aphids, the predator Harmonia axyridis (P.) and the parasitoid Aphidius colemani (V.), in no-choice experiments under laboratory conditions. The number of Rhopalosiphum padi (L.) and Sitobion avenae (F.) killed was increased by increasing the concentration of V. lecanii. The timing of application of fungus to aphids affected the efficacy of other biocontrol agents, a parasitoid and a predator. Parasitation by A. colemani (V.) in both cereal aphids (S. avenae and R. padi) was not affected by V. lecanii when aphids were first treated with V. lecanii and then exposed to A. colemani. The emergence of adults from parasitised mummies was, however, lower in infected aphids than in uninfected aphids when the aphids were first exposed to the parasitoids and then treated with fungus. The female sex ratio in the emerging adults was lower in V. lecanii-treated aphids in both species. When aphids were first treated with V. lecanii, 72 h before predation, fewer aphids of both species were consumed by H. axyridis (P.). Use of entomopathogenic fungus as a biological control agent could be a complementary strategy in an integrated pest management programme against cereal aphids, but it can reduce the efficiency of other biocontrol agents (parasitoids and predators) when applied simultaneously. © 2012 Society of Chemical Industry.

  15. Within-plant distribution of cotton aphids, Aphis gossypii Glover (Hemiptera: Aphididae), in Bt and non-Bt cotton fields.

    PubMed

    Fernandes, F S; Ramalho, F S; Nascimento, J L; Malaquias, J B; Nascimento, A R B; Silva, C A D; Zanuncio, J C

    2012-02-01

    Knowledge of the vertical and horizontal distribution of Aphis gossypii Glover (Hemiptera: Aphididae) on genetically modified cotton plants over time could help optimize decision-making in integrated cotton aphid management programs. Therefore, the aim of the present study was to determine the vertical and horizontal distribution of A. gossypii in non-transgenic Bt cotton and transgenic Bt-cotton over time during two cotton seasons by examining plants throughout the seasons. There was no significant interaction between years and cotton cultivar treatments for apterous or alate aphids. Considering year-to-year data, analyses on season-long averages of apterous or alate aphids showed that aphid densities per plant did not differ among years. The number of apterous aphids found per plant for the Bt transgenic cultivar (2427 apterous aphids per plant) was lower than for its isoline (3335 apterous aphids per plant). The number of alate aphids found per plant on the Bt transgenic cultivar (12.28 alate aphids per plant) was lower than for the isoline (140.56 alate aphids per plant). With regard to the vertical distribution of apterous aphids or alate aphids, there were interactions between cotton cultivar, plant age and plant region. We conclude that in comparison to non-Bt cotton (DP 4049), Bt cotton (DP 404 BG (Bollgard)) has significant effects on the vertical, horizontal, spatial and temporal distribution patterns of A. gossypii, showing changes in its distribution behaviour inside the plant as the cotton crop develops. The results of our study are relevant for understanding the vertical and horizontal distribution of A. gossypii on Bt cotton cultivar (DP 404 BG (Bollgard)) and on its isoline (DP 4049), and could be useful in decision-making, implementing controls and determining the timing of population peaks of this insect.

  16. Foliar aphid feeding recruits rhizosphere bacteria and primes plant immunity against pathogenic and non-pathogenic bacteria in pepper

    PubMed Central

    Lee, Boyoung; Lee, Soohyun; Ryu, Choong-Min

    2012-01-01

    Background and Aims Plants modulate defence signalling networks in response to different biotic stresses. The present study evaluated the effect of a phloem-sucking aphid on plant defence mechanisms in pepper (Capsicum annuum) during subsequent pathogen attacks on leaves and rhizosphere bacteria on roots. Methods Plants were pretreated with aphids and/or the chemical trigger benzothiadiazol (BTH) 7 d before being challenged with two pathogenic bacteria, Xanthomonas axonopodis pv. vesicatoria (Xav) as a compatible pathogen and X. axonopodis pv. glycines (Xag) as an incompatible (non-host) pathogen. Key Results Disease severity was noticeably lower in aphid- and BTH + aphid-treated plants than in controls. Although treatment with BTH or aphids alone did not affect the hypersensitive response (HR) against Xag strain 8ra, the combination treatment had a synergistic effect on the HR. The aphid population was reduced by BTH pretreatment and by combination treatment with BTH and bacterial pathogens in a synergistic manner. Analysis of the expression of the defence-related genes Capsicum annum pathogenesis-related gene 9 (CaPR9), chitinase 2 (CaCHI2), SAR8·2 and Lipoxygenase1 (CaLOX1) revealed that aphid infestation resulted in the priming of the systemic defence responses against compatible and incompatible pathogens. Conversely, pre-challenge with the compatible pathogen Xav on pepper leaves significantly reduced aphid numbers. Aphid infestation increased the population of the beneficial Bacillus subtilis GB03 but reduced that of the pathogenic Ralstonia solanacearum SL1931. The expression of defence-related genes in the root and leaf after aphid feeding indicated that the above-ground aphid infestation elicited salicylic acid and jasmonic acid signalling throughout the whole plant. Conclusions The findings of this study show that aphid feeding elicits plant resistance responses and attracts beneficial bacterial populations to help the plant cope with subsequent

  17. Loss of function of FATTY ACID DESATURASE7 in tomato enhances basal aphid resistance in a salicylate-dependent manner.

    PubMed

    Avila, Carlos A; Arévalo-Soliz, Lirio M; Jia, Lingling; Navarre, Duroy A; Chen, Zhaorigetu; Howe, Gregg A; Meng, Qing-Wei; Smith, Jonathon E; Goggin, Fiona L

    2012-04-01

    We report here that disruption of function of the ω-3 FATTY ACID DESATURASE7 (FAD7) enhances plant defenses against aphids. The suppressor of prosystemin-mediated responses2 (spr2) mutation in tomato (Solanum lycopersicum), which eliminates the function of FAD7, reduces the settling behavior, survival, and fecundity of the potato aphid (Macrosiphum euphorbiae). Likewise, the antisense suppression of LeFAD7 expression in wild-type tomato plants reduces aphid infestations. Aphid resistance in the spr2 mutant is associated with enhanced levels of salicylic acid (SA) and mRNA encoding the pathogenesis-related protein P4. Introduction of the Naphthalene/salicylate hydroxylase transgene, which suppresses SA accumulation, restores wild-type levels of aphid susceptibility to spr2. Resistance in spr2 is also lost when we utilize virus-induced gene silencing to suppress the expression of NONEXPRESSOR OF PATHOGENESIS-RELATED PROTEINS1 (NPR1), a positive regulator of many SA-dependent defenses. These results indicate that FAD7 suppresses defenses against aphids that are mediated through SA and NPR1. Although loss of function of FAD7 also inhibits the synthesis of jasmonate (JA), the effects of this desaturase on aphid resistance are not dependent on JA; other mutants impaired in JA synthesis (acx1) or perception (jai1-1) show wild-type levels of aphid susceptibility, and spr2 retains aphid resistance when treated with methyl jasmonate. Thus, FAD7 may influence JA-dependent defenses against chewing insects and SA-dependent defenses against aphids through independent effects on JA synthesis and SA signaling. The Arabidopsis (Arabidopsis thaliana) mutants Atfad7-2 and Atfad7-1fad8 also show enhanced resistance to the green peach aphid (Myzus persicae) compared with wild-type controls, indicating that FAD7 influences plant-aphid interactions in at least two plant families.

  18. Winged Pea Aphids Can Modify Phototaxis in Different Development Stages to Assist Their Host Distribution

    PubMed Central

    Zhang, Yi; Wang, Xing-Xing; Jing, Xiangfeng; Tian, Hong-Gang; Liu, Tong-Xian

    2016-01-01

    The pea aphid, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae), shows wing polyphenism (winged and wingless morphs) in its life cycle. The winged morph is adapted for dispersal; its two developmental adult stages (for dispersal and reproduction) are based on its breeding periods. The two morphs show different phototactic behavior and the winged can change its preference to light according to the developmental stages. To determine the mechanism and ecological functions of phototaxis for A. pisum, we first investigated the phototaxis of the two aphid morphs at different stages and analyzed the phototactic response to lights of different wavelengths; the correlation between alate fecundity and their phototactic behaviors were then studied. Finally, we focused on the possible functions of phototaxis in aphid host location and distribution in combination with gravitaxis behaviors. Negative phototaxis was found for breeding winged adults but all the other stages of both winged and wingless morphs showed positive phototaxis. The reactions of the aphids to different wavelengths were also different. Nymph production in winged adults showed negative correlation to phototaxis. The dopamine pathway was possibly involved in these behavior modifications. We speculated that winged adults can use light for dispersal in the early dispersal stage and for position holding in the breeding stage. Based on our results, we assume that light signals are important for aphid dispersal and distribution, and are also essential for the pea aphids to cope with environmental changes. PMID:27531980

  19. Expression Profiling of Selected Glutathione Transferase Genes in Zea mays (L.) Seedlings Infested with Cereal Aphids

    PubMed Central

    Sytykiewicz, Hubert; Chrzanowski, Grzegorz; Czerniewicz, Paweł; Sprawka, Iwona; Łukasik, Iwona; Goławska, Sylwia; Sempruch, Cezary

    2014-01-01

    The purpose of this report was to evaluate the expression patterns of selected glutathione transferase genes (gst1, gst18, gst23 and gst24) in the tissues of two maize (Zea mays L.) varieties (relatively resistant Ambrozja and susceptible Tasty Sweet) that were colonized with oligophagous bird cherry-oat aphid (Rhopalosiphum padi L.) or monophagous grain aphid (Sitobion avenae L.). Simultaneously, insect-triggered generation of superoxide anion radicals (O2•−) in infested Z. mays plants was monitored. Quantified parameters were measured at 1, 2, 4, 8, 24, 48 and 72 h post-initial aphid infestation (hpi) in relation to the non-infested control seedlings. Significant increases in gst transcript amounts were recorded in aphid-stressed plants in comparison to the control seedlings. Maximal enhancement in the expression of the gst genes in aphid-attacked maize plants was found at 8 hpi (gst23) or 24 hpi (gst1, gst18 and gst24) compared to the control. Investigated Z. mays cultivars formed excessive superoxide anion radicals in response to insect treatments, and the highest overproduction of O2•− was noted 4 or 8 h after infestation, depending on the aphid treatment and maize genotype. Importantly, the Ambrozja variety could be characterized as having more profound increments in the levels of gst transcript abundance and O2•− generation in comparison with the Tasty Sweet genotype. PMID:25365518

  20. Aphid Parasitoid Mothers Don't Always Know Best through the Whole Host Selection Process

    PubMed Central

    Chesnais, Quentin; Ameline, Arnaud; Doury, Géraldine; Le Roux, Vincent; Couty, Aude

    2015-01-01

    Parasitoid host selection behaviour has been extensively studied in experimentally simplified tritrophic systems formed by one single food chain (one plant, one herbivore and one parasitoid species). The "Mother knows best" hypothesis predicts that the preference for a plant-host complex should be positively correlated with plant quality for offspring performance. We studied the host selection behaviour of the generalist endoparasitoid Aphidius matricariae towards the black bean aphid Aphis fabae in the intercrop system including Vicia faba as a focal plant and its companion plant Camelina sativa. Dual-choice laboratory bioassays revealed that parasitoid females preferred to orientate towards (1) the plant-aphid complex over the non-infested plant whatever the complex (2) the C. sativa-A. fabae complex over the V. faba-A. fabae complex. In dual choice attack rate bioassays, parasitoid females showed more interest towards the aphids on C. sativa but paradoxically chose to oviposit more in aphids on V. faba. Ultimately, parasitoids that had developed on the V. faba-A. fabae complex exhibited better fitness parameters. By demonstrating that parasitoid females were able to discriminate the aphid host that offered the highest fitness to their offspring but selected beforehand the least suitable plant-aphid complex, we provide key insight into the disruption in their host selection behaviour potentially triggered by diverse habitats. This suggests that the "Mother knows best" hypothesis could be thwarted by increasing the complexity of the studied systems. PMID:26270046

  1. Large-Scale Label-Free Quantitative Proteomics of the Pea aphid-Buchnera Symbiosis*

    PubMed Central

    Poliakov, Anton; Russell, Calum W.; Ponnala, Lalit; Hoops, Harold J.; Sun, Qi; Douglas, Angela E.; van Wijk, Klaas J.

    2011-01-01

    Many insects are nutritionally dependent on symbiotic microorganisms that have tiny genomes and are housed in specialized host cells called bacteriocytes. The obligate symbiosis between the pea aphid Acyrthosiphon pisum and the γ-proteobacterium Buchnera aphidicola (only 584 predicted proteins) is particularly amenable for molecular analysis because the genomes of both partners have been sequenced. To better define the symbiotic relationship between this aphid and Buchnera, we used large-scale, high accuracy tandem mass spectrometry (nanoLC-LTQ-Orbtrap) to identify aphid and Buchnera proteins in the whole aphid body, purified bacteriocytes, isolated Buchnera cells and the residual bacteriocyte fraction. More than 1900 aphid and 400 Buchnera proteins were identified. All enzymes in amino acid metabolism annotated in the Buchnera genome were detected, reflecting the high (68%) coverage of the proteome and supporting the core function of Buchnera in the aphid symbiosis. Transporters mediating the transport of predicted metabolites were present in the bacteriocyte. Label-free spectral counting combined with hierarchical clustering, allowed to define the quantitative distribution of a subset of these proteins across both symbiotic partners, yielding no evidence for the selective transfer of protein among the partners in either direction. This is the first quantitative proteome analysis of bacteriocyte symbiosis, providing a wealth of information about molecular function of both the host cell and bacterial symbiont. PMID:21421797

  2. Identification of differentially expressed genes related to aphid resistance in cucumber (Cucumis sativus L.).

    PubMed

    Liang, Danna; Liu, Min; Hu, Qijing; He, Min; Qi, Xiaohua; Xu, Qiang; Zhou, Fucai; Chen, Xuehao

    2015-05-11

    Cucumber, a very important vegetable crop worldwide, is easily damaged by pests. Aphids (Aphis gossypii Glover) are among the most serious pests in cucumber production and often cause severe loss of yield and make fruit quality get worse. Identifying genes that render cucumbers resistant to aphid-induced damage and breeding aphid-resistant cucumber varieties have become the most promising control strategies. In this study, a Illumina Genome Analyzer platform was applied to monitor changes in gene expression in the whole genome of the cucumber cultivar 'EP6392' which is resistant to aphids. Nine DGE libraries were constructed from infected and uninfected leaves. In total, 49 differentially expressed genes related to cucumber aphid resistance were screened during the treatment period. These genes are mainly associated with signal transduction, plant-pathogen interactions, flavonoid biosynthesis, amino acid metabolism and sugar metabolism pathways. Eight of the 49 genes may be associated with aphid resistance. Finally, expression of 9 randomly selected genes was evaluated by qRT-PCR to verify the results for the tag-mapped genes. With the exception of 1-aminocyclopropane-1-carboxylate oxidase homolog 6, the expression of the chosen genes was in agreement with the results of the tag-sequencing analysis patterns.

  3. [An example of research on biological control: Entomophthora fungi pathogenic for aphids].

    PubMed

    Latgé, J P; Remaudière, G; Papierok, B

    1978-01-01

    The results obtained in 15 years of research on the Entomophthorales pathogen of aphids showed the importance of the action of these fungi in the regulation of natural aphid populations and their possible use in agriculture as a biological control agent. Recent ecological studies on natural populations of aphids established the seasonal variation of the different fungal species and the diverse degrees of specificity between the species or groups of species of aphid and the various species of Entomophthora. The study of populations dynamics of an aphid species on a cultivated plant permitted the determination of the way a certain number of biotic and abiotic factors, such as temperature, humidity, thresholds of the insect population and of the infecting fungus lead to an epizootic development. If the air propagation of the disease by conidia is understood for a long time, the role of the soil as a reservoir for the infecting fungus has been demonstrated recently. Under favourable climatic conditions, the use of industrially produced resistant resting spores would allow the regulation of aphid populations in nature.

  4. A multi-approach study to delineate interactions between carabid beetles and soybean aphids.

    PubMed

    Firlej, Annabelle; Doyon, Josée; Harwood, James D; Brodeur, Jacques

    2013-02-01

    In recent years, the soybean aphid, Aphis glycines Matsumura, has become the most important exotic pest of soybean, Glycine max (L.) Merrill, in North America. Given the significant yield losses that are reported, considerable effort has been expended to characterize the natural enemy community associated with this pest. Several indigenous and naturalized predators have been identified as potential biological control agents, and these include carabid beetles, an abundant and important family of aphid predators. The objectives of this study were to assess the incidence of field predation by Pterostichus melanarius (Illiger), the most common carabid species in Québec soybeans, using molecular gut-content analysis, and to quantify its impact on A. glycines populations through laboratory and field cage experiments. Throughout the growing season between 16.8% (during low aphid density) and 33.7% (at times of high aphid density) of P. melanarius tested positive for aphid DNA. Furthermore, although laboratory feeding trials confirmed that P. melanarius prey on A. glycines, short-term field cage experiments failed to demonstrate a significant reduction of A. glycines populations by carabid beetles. These results suggest a relatively weak interaction between P. melanarius and A. glycines when pest densities are high, but the high predation rate when aphid densities are particularly low suggests these natural enemies may function as important early-season predators.

  5. Winged Pea Aphids Can Modify Phototaxis in Different Development Stages to Assist Their Host Distribution.

    PubMed

    Zhang, Yi; Wang, Xing-Xing; Jing, Xiangfeng; Tian, Hong-Gang; Liu, Tong-Xian

    2016-01-01

    The pea aphid, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae), shows wing polyphenism (winged and wingless morphs) in its life cycle. The winged morph is adapted for dispersal; its two developmental adult stages (for dispersal and reproduction) are based on its breeding periods. The two morphs show different phototactic behavior and the winged can change its preference to light according to the developmental stages. To determine the mechanism and ecological functions of phototaxis for A. pisum, we first investigated the phototaxis of the two aphid morphs at different stages and analyzed the phototactic response to lights of different wavelengths; the correlation between alate fecundity and their phototactic behaviors were then studied. Finally, we focused on the possible functions of phototaxis in aphid host location and distribution in combination with gravitaxis behaviors. Negative phototaxis was found for breeding winged adults but all the other stages of both winged and wingless morphs showed positive phototaxis. The reactions of the aphids to different wavelengths were also different. Nymph production in winged adults showed negative correlation to phototaxis. The dopamine pathway was possibly involved in these behavior modifications. We speculated that winged adults can use light for dispersal in the early dispersal stage and for position holding in the breeding stage. Based on our results, we assume that light signals are important for aphid dispersal and distribution, and are also essential for the pea aphids to cope with environmental changes.

  6. Identification of differentially expressed genes related to aphid resistance in cucumber (Cucumis sativus L.)

    PubMed Central

    Liang, Danna; Liu, Min; Hu, Qijing; He, Min; Qi, Xiaohua; Xu, Qiang; Zhou, Fucai; Chen, Xuehao

    2015-01-01

    Cucumber, a very important vegetable crop worldwide, is easily damaged by pests. Aphids (Aphis gossypii Glover) are among the most serious pests in cucumber production and often cause severe loss of yield and make fruit quality get worse. Identifying genes that render cucumbers resistant to aphid-induced damage and breeding aphid-resistant cucumber varieties have become the most promising control strategies. In this study, a Illumina Genome Analyzer platform was applied to monitor changes in gene expression in the whole genome of the cucumber cultivar ‘EP6392’ which is resistant to aphids. Nine DGE libraries were constructed from infected and uninfected leaves. In total, 49 differentially expressed genes related to cucumber aphid resistance were screened during the treatment period. These genes are mainly associated with signal transduction, plant-pathogen interactions, flavonoid biosynthesis, amino acid metabolism and sugar metabolism pathways. Eight of the 49 genes may be associated with aphid resistance. Finally, expression of 9 randomly selected genes was evaluated by qRT-PCR to verify the results for the tag-mapped genes. With the exception of 1-aminocyclopropane-1-carboxylate oxidase homolog 6, the expression of the chosen genes was in agreement with the results of the tag-sequencing analysis patterns. PMID:25959296

  7. Importance of olfactory and visual signals of autumn leaves in the coevolution of aphids and trees.

    PubMed

    Holopainen, Jarmo K

    2008-09-01

    Deciduous trees remobilize the nitrogen in senescing leaves during the process of autumn colouration, which in many species is associated with increased concentrations of anthocyanins. Archetti and Hamilton and Brown observed that autumn colouration is stronger in tree species facing a high diversity of specialist aphids. They proposed a coevolution theory that the bright colours in autumn might provide an honest signal of defence commitment, thus deterring migrant aphids from settling on the leaves. So far, there have been very few experimental results to support the hypothesis, and tree commitment to phenolics-based defences has not shown direct protection against aphids. Predators and parasitoids have been found to be the major controllers of arboreal aphids. Indirect defences involve the emission of attractive volatile compounds that enhance the effectiveness of carnivorous enemies. The indirect defence hypothesis is presented to explain low aphid diversity on tree species that are green during autumn. The hypothesis suggests that green foliage can continue to produce herbivore-inducible plant volatiles and maintain volatile-based indirect plant defences against aphids until leaf abscission.

  8. Evaluation of late vegetative and reproductive stage soybeans for resistance to soybean aphid (Hemiptera: Aphididae).

    PubMed

    Prochaska, T J; Pierson, L M; Baldin, E L L; Hunt, T E; Heng-Moss, T M; Reese, J C

    2013-04-01

    The soybean aphid, Aphis glycines Matsumura, has become the most significant soybean [Glycine max (L.) Merrill] insect pest in the north central soybean production region of North America. The objectives of this research were to measure selected genotypes for resistance to the soybean aphid in the later vegetative and reproductive stages under field conditions, and confirm the presence of tolerance in KS4202. The results from 2007 to 2011 indicate that KS4202 can support aphid populations with minimal yield loss at levels where significant yield loss would be expected in most other genotypes. The common Nebraska cultivar, 'Asgrow 2703', appears to show signs of tolerance as well. None of the yield parameters were significantly different between the aphid infested and noninfested treatments. Based on our results, genotypes may compensate for aphid feeding in different ways. Asgrow 2703 appears to produce a similar number of seeds as its noninfested counterpart, although the seeds produced are slightly smaller. Field evaluation of tolerance in KS4202 indicated a yield loss of only 13% at 34,585-53,508 cumulative aphid-days, when 24-36% yield loss would have been expected.

  9. High-throughput phenotyping of plant resistance to aphids by automated video tracking.

    PubMed

    Kloth, Karen J; Ten Broeke, Cindy Jm; Thoen, Manus Pm; Hanhart-van den Brink, Marianne; Wiegers, Gerrie L; Krips, Olga E; Noldus, Lucas Pjj; Dicke, Marcel; Jongsma, Maarten A

    2015-01-01

    Piercing-sucking insects are major vectors of plant viruses causing significant yield losses in crops. Functional genomics of plant resistance to these insects would greatly benefit from the availability of high-throughput, quantitative phenotyping methods. We have developed an automated video tracking platform that quantifies aphid feeding behaviour on leaf discs to assess the level of plant resistance. Through the analysis of aphid movement, the start and duration of plant penetrations by aphids were estimated. As a case study, video tracking confirmed the near-complete resistance of lettuce cultivar 'Corbana' against Nasonovia ribisnigri (Mosely), biotype Nr:0, and revealed quantitative resistance in Arabidopsis accession Co-2 against Myzus persicae (Sulzer). The video tracking platform was benchmarked against Electrical Penetration Graph (EPG) recordings and aphid population development assays. The use of leaf discs instead of intact plants reduced the intensity of the resistance effect in video tracking, but sufficiently replicated experiments resulted in similar conclusions as EPG recordings and aphid population assays. One video tracking platform could screen 100 samples in parallel. Automated video tracking can be used to screen large plant populations for resistance to aphids and other piercing-sucking insects.

  10. Oviposition response of green lacewings (Neuroptera: Chrysopidae) to aphids (Hemiptera: Aphididae) and potential attractants on pecan.

    PubMed

    Kunkel, Brian A; Cottrell, Ted E

    2007-06-01

    Pecan foliage is attacked by three species of aphids [Monellia caryella (Fitch), Melanocallis caryaefoliae (Davis), and Monelliopsis pecanis Bissell], resulting in damage that can reduce tree nut yield. In this study, we assayed the ovipositional response of the green lacewing Chrysoperla rufilabris (Burmeister) to M. caryella and M. caryaefoliae at high and low aphid densities and the development of C. rufilabris larvae when fed solely on each of the three pecan aphid species. During 2004 and 2005, combinations of attractants and food sprays were applied to pecan trees in an orchard to monitor green lacewing ovipositional response. We found that C. rufilabris laid more eggs on seedling trees infested with the M. caryella (at both high and low densities) than on seedlings infested with M. caryaefoliae. Development of C. rufilabris was unaffected by aphid species. At least one attractant/food spray treatment applied to trees in an orchard significantly increased green lacewing oviposition for three of the five treatment dates over both years. These results show that larvae of C. rufilabris will consume all aphid species attacking pecan, even though female ovipositional response can differ for aphid species. It is likely that combinations of attractants and food sprays can be used to enhance green lacewing populations in orchards.

  11. Expression profiling of selected glutathione transferase genes in Zea mays (L.) seedlings infested with cereal aphids.

    PubMed

    Sytykiewicz, Hubert; Chrzanowski, Grzegorz; Czerniewicz, Paweł; Sprawka, Iwona; Łukasik, Iwona; Goławska, Sylwia; Sempruch, Cezary

    2014-01-01

    The purpose of this report was to evaluate the expression patterns of selected glutathione transferase genes (gst1, gst18, gst23 and gst24) in the tissues of two maize (Zea mays L.) varieties (relatively resistant Ambrozja and susceptible Tasty Sweet) that were colonized with oligophagous bird cherry-oat aphid (Rhopalosiphum padi L.) or monophagous grain aphid (Sitobion avenae L.). Simultaneously, insect-triggered generation of superoxide anion radicals (O2•-) in infested Z. mays plants was monitored. Quantified parameters were measured at 1, 2, 4, 8, 24, 48 and 72 h post-initial aphid infestation (hpi) in relation to the non-infested control seedlings. Significant increases in gst transcript amounts were recorded in aphid-stressed plants in comparison to the control seedlings. Maximal enhancement in the expression of the gst genes in aphid-attacked maize plants was found at 8 hpi (gst23) or 24 hpi (gst1, gst18 and gst24) compared to the control. Investigated Z. mays cultivars formed excessive superoxide anion radicals in response to insect treatments, and the highest overproduction of O2•- was noted 4 or 8 h after infestation, depending on the aphid treatment and maize genotype. Importantly, the Ambrozja variety could be characterized as having more profound increments in the levels of gst transcript abundance and O2•- generation in comparison with the Tasty Sweet genotype.

  12. Proteomic Profiling of Cereal Aphid Saliva Reveals Both Ubiquitous and Adaptive Secreted Proteins

    PubMed Central

    Wilkinson, Tom L.

    2013-01-01

    The secreted salivary proteins from two cereal aphid species, Sitobion avenae and Metopolophium dirhodum, were collected from artificial diets and analysed by tandem mass spectrometry. Protein identification was performed by searching MS data against the official protein set from the current pea aphid (Acyrthosiphon pisum) genome assembly and revealed 12 and 7 proteins in the saliva of S. avenae and M. dirhodum, respectively. When combined with a comparable dataset from A. pisum, only three individual proteins were common to all the aphid species; two paralogues of the GMC oxidoreductase family (glucose dehydrogenase; GLD) and ACYPI009881, an aphid specific protein previously identified as a putative component of the salivary sheath. Antibodies were designed from translated protein sequences obtained from partial cDNA sequences for ACYPI009881 and both saliva associated GLDs. The antibodies detected all parent proteins in secreted saliva from the three aphid species, but could only detect ACYPI009881, and not saliva associated GLDs, in protein extractions from the salivary glands. This result was confirmed by immunohistochemistry using whole and sectioned salivary glands, and in addition, localised ACYPI009881 to specific cell types within the principal salivary gland. The implications of these findings for the origin of salivary components and the putative role of the proteins identified are discussed in the context of our limited understanding of the functional relationship between aphid saliva and the plants they feed on. The mass spectrometry data have been deposited to the ProteomeXchange and can be accessed under the identifier PXD000113. PMID:23460852

  13. Aphid and ladybird beetle abundance depend on the interaction of spatial effects and genotypic diversity.

    PubMed

    Genung, Mark A; Crutsinger, Gregory M; Bailey, Joseph K; Schweitzer, Jennifer A; Sanders, Nathan J

    2012-01-01

    Intraspecific variation and genotypic diversity of host-plants can affect the structure of associated arthropod communities and the dynamics of populations. Similarly, neighboring plants can also affect interactions between host-plants and their associated arthropods. However, most studies on the effects of host-plant genotypes have largely ignored the potential effects of neighboring host-plants on arthropod communities. In this study, we used a common garden experiment to ask how spatial effects of neighboring patches, along with genotype identity and genotypic diversity in tall goldenrod (Solidago altissima), affect the abundances of a common goldenrod herbivore (Uroleucon nigrotuberculatum) and their dominant predator (Harmonia axyridis, a ladybird beetle). Aphid abundance varied 80-fold among genotypes, while ladybird beetle abundance was not affected by genotype identity. Additionally, there were strong effects of neighboring plots: aphid abundance in a focal plot was positively correlated to aphid abundance in nearby plots, suggesting strong spatial patterning in the abundance of aphids. Neither aphid nor ladybird beetle abundance was affected by genotypic diversity. However, focal plot genotypic diversity mediated the strength of the neighborhood effect (i.e., strong effects for genotype polyculture focal plots and weak effects for genotype monoculture focal plots). Our results show that aphids were directly influenced by host-plant genotype identity while ladybird beetles responded mainly to prey abundance, and suggest that genotypic diversity can influence the effects of spatial processes on the plant-herbivore interactions.

  14. Proteomic profiling of cereal aphid saliva reveals both ubiquitous and adaptive secreted proteins.

    PubMed

    Rao, Sohail A K; Carolan, James C; Wilkinson, Tom L

    2013-01-01

    The secreted salivary proteins from two cereal aphid species, Sitobion avenae and Metopolophium dirhodum, were collected from artificial diets and analysed by tandem mass spectrometry. Protein identification was performed by searching MS data against the official protein set from the current pea aphid (Acyrthosiphon pisum) genome assembly and revealed 12 and 7 proteins in the saliva of S. avenae and M. dirhodum, respectively. When combined with a comparable dataset from A. pisum, only three individual proteins were common to all the aphid species; two paralogues of the GMC oxidoreductase family (glucose dehydrogenase; GLD) and ACYPI009881, an aphid specific protein previously identified as a putative component of the salivary sheath. Antibodies were designed from translated protein sequences obtained from partial cDNA sequences for ACYPI009881 and both saliva associated GLDs. The antibodies detected all parent proteins in secreted saliva from the three aphid species, but could only detect ACYPI009881, and not saliva associated GLDs, in protein extractions from the salivary glands. This result was confirmed by immunohistochemistry using whole and sectioned salivary glands, and in addition, localised ACYPI009881 to specific cell types within the principal salivary gland. The implications of these findings for the origin of salivary components and the putative role of the proteins identified are discussed in the context of our limited understanding of the functional relationship between aphid saliva and the plants they feed on. The mass spectrometry data have been deposited to the ProteomeXchange and can be accessed under the identifier PXD000113.

  15. Molecular responses to aphid feeding in Arabidopsis in relation to plant defense pathways.

    PubMed

    Moran, P J; Thompson, G A

    2001-02-01

    Little is known about molecular responses in plants to phloem feeding by insects. The induction of genes associated with wound and pathogen response pathways was investigated following green peach aphid (Myzus persicae) feeding on Arabidopsis. Aphid feeding on rosette leaves induced transcription of two genes associated with salicylic acid (SA)-dependent responses to pathogens (PR-1 and BGL2) 10- and 23-fold, respectively. Induction of PR-1 and BGL2 mRNA was reduced in npr1 mutant plants, which are deficient in SA signaling. Application of the SA analog benzothiadiazole led to decreases in aphid reproduction on leaves of both wild-type plants and mutant plants deficient in responsiveness to SA, suggesting that wild-type SA-dependent responses do not influence resistance to aphids. Two-fold increases occurred in mRNA levels of PDF1.2, which encodes defensin, a peptide involved in the jasmonate (JA)-/ethylene-dependent response pathway. Transcripts encoding JA-inducible lipoxygenase (LOX2) and SA/JA-inducible Phe-ammonia lyase increased 1.5- to 2-fold. PDF1.2 and LOX2 induction by aphids did not occur in infested leaves of the JA-resistant coi1-1 mutant. Aphid feeding induced 10-fold increases in mRNA levels of a stress-related monosaccharide symporter gene, STP4. Phloem feeding on Arabidopsis leads to stimulation of response pathways associated with both pathogen infection and wounding.

  16. Comparative analysis of Solanum stoloniferum responses to probing by the green peach aphid Myzus persicae and the potato aphid Macrosiphum euphorbiae.

    PubMed

    Alvarez, Adriana E; Broglia, Viviana G; Alberti D'Amato, Anahí M; Wouters, Doret; van der Vossen, Edwin; Garzo, Elisa; Tjallingii, W Fred; Dicke, Marcel; Vosman, Ben

    2013-04-01

    Plants protect themselves against aphid attacks by species-specific defense mechanisms. Previously, we have shown that Solanum stoloniferum Schlechtd has resistance factors to Myzus persicae Sulzer (Homoptera: Aphididae) at the epidermal/mesophyll level that are not effective against Macrosiphum euphorbiae Thomas (Homoptera: Aphididae). Here, we compare the nymphal mortality, the pre-reproductive development time, and the probing behavior of M. persicae and M. euphorbiae on S. stoloniferum and Solanum tuberosum L. Furthermore, we analyze the changes in gene expression in S. stoloniferum 96 hours post infestation by either aphid species. Although the M. euphorbiae probing behavior shows that aphids encounter more probing constrains on phloem activities-longer probing and salivation time- on S. stoloniferum than on S. tuberosum, the aphids succeeded in reaching a sustained ingestion of phloem sap on both plants. Probing by M. persicae on S. stoloniferum plants resulted in limited feeding only. Survival of M. euphorbiae and M. persicae was affected on young leaves, but not on senescent leaves of S. stoloniferum. Infestation by M. euphorbiae changed the expression of more genes than M. persicae did. At the systemic level both aphids elicited a weak response. Infestation of S. stoloniferum plants with a large number of M. persicae induced morphological changes in the leaves, leading to the development of pustules that were caused by disrupted vascular parenchyma and surrounding tissue. In contrast, an infestation by M. euphorbiae had no morphological effects. Both plant species can be regarded as good host for M. euphorbiae, whereas only S. tuberosum is a good host for M. persicae and S. stoloniferum is not. Infestation of S. stoloniferum by M. persicae or M. euphorbiae changed the expression of a set of plant genes specific for each of the aphids as well as a set of common genes. © 2012 The Authors Insect Science © 2012 Institute of Zoology, Chinese Academy of

  17. Alternaria toxin-induced resistance against rose aphids and olfactory response of aphids to toxin-induced volatiles of rose plants.

    PubMed

    Yang, Fa-zhong; Li, Li; Yang, Bin

    2012-02-01

    The search for active toxins for managing weeds or plant diseases is believed to be a promising avenue of investigation. However, the effects of Alternaria toxins on insects have just begun to be investigated. Bioactivities of toxins from four strains of Alternaria alternata on Rosa chinensis and rose aphid Macrosiphum rosivorum were tested in the present study. At a concentration of 50.0 μg/ml, the crude extract (toxin) of strain 7484 was found not to be harmful to rose plants with excised leaf-puncture method (P≥0.079), and rose plants showed enhanced resistance to rose aphids when this Alternaria toxin was sprayed on the plants (P≤0.001). However, this toxin caused no detrimental effects on aphids in insecticidal bioassay at a concentration of 10.0 to 160.0 μg/ml (P≥0.096). Therefore, the Alternaria toxin had significantly induced the resistance of rose plants against rose aphids, demonstrating that the resistance mechanism triggered by the Alternaria toxin in the rose plant may also be used by the plant to defend itself against insects. Further bioassays aimed to discover the olfactory responses of aphids to the toxin-induced volatiles of host plants. The aphids were significantly more attracted to both volatiles emitted and collected from control rose plants than to both volatiles emitted and collected from the toxin-treated rose plants (P≤0.014). This result showed that the toxin-induced resistance related to the volatile changes of host plants.

  18. A protein from the salivary glands of the pea aphid, Acyrthosiphon pisum, is essential in feeding on a host plant.

    PubMed

    Mutti, Navdeep S; Louis, Joe; Pappan, Loretta K; Pappan, Kirk; Begum, Khurshida; Chen, Ming-Shun; Park, Yoonseong; Dittmer, Neal; Marshall, Jeremy; Reese, John C; Reeck, Gerald R

    2008-07-22

    In feeding, aphids inject saliva into plant tissues, gaining access to phloem sap and eliciting (and sometimes overcoming) plant responses. We are examining the involvement, in this aphid-plant interaction, of individual aphid proteins and enzymes, as identified in a salivary gland cDNA library. Here, we focus on a salivary protein we have arbitrarily designated Protein C002. We have shown, by using RNAi-based transcript knockdown, that this protein is important in the survival of the pea aphid (Acyrthosiphon pisum) on fava bean, a host plant. Here, we further characterize the protein, its transcript, and its gene, and we study the feeding process of knockdown aphids. The encoded protein fails to match any protein outside of the family Aphididae. By using in situ hybridization and immunohistochemistry, the transcript and the protein were localized to a subset of secretory cells in principal salivary glands. Protein C002, whose sequence contains an N-terminal secretion signal, is injected into the host plant during aphid feeding. By using the electrical penetration graph method on c002-knockdown aphids, we find that the knockdown affects several aspects of foraging and feeding, with the result that the c002-knockdown aphids spend very little time in contact with phloem sap in sieve elements. Thus, we infer that Protein C002 is crucial in the feeding of the pea aphid on fava bean.

  19. Hoverfly preference for high honeydew amounts creates enemy-free space for aphids colonizing novel host plants.

    PubMed

    Vosteen, Ilka; Gershenzon, Jonathan; Kunert, Grit

    2016-09-01

    The existence of an enemy-free space can play an important role in aphid host race formation processes, but little is known about the mechanisms that create an area of low predation pressure on particular host plants. In this paper, we identify a mechanism generating lower predation pressure that promotes the maintenance of the different host races of the pea aphid (Acyrthosiphon pisum) complex, a well-studied model for ecological speciation. The pea aphid consists of at least 15 genetically distinct host races which are native to specific host plants of the legume family, but can all develop on the universal host plant Vicia faba. Previous work showed that hoverfly (Episyrphus balteatus) oviposition preferences contribute to the enemy-free space that helps to maintain the different pea aphid host races, and that higher amounts of honeydew are more attractive to ovipositing hoverflies. Here we demonstrated that aphid honeydew is produced in large amounts when aphid reproduction rate was highest, and is an important oviposition cue for hoverflies under field conditions. However, on less suitable host plants, where honeydew production is reduced, pea aphids enjoy lower predation rates. A reduction in enemy pressure can mitigate the performance disadvantages of aphids colonizing a novel host and probably plays an important role in pea aphid host race formation.

  20. Characterization of the natural enemy community attacking cotton aphid in the Bt cotton ecosystem in Northern China.

    PubMed

    Ali, Abid; Desneux, Nicolas; Lu, Yanhui; Liu, Bing; Wu, Kongming

    2016-04-14

    Planting Bt cotton in China since 1997 has led to important changes in the natural enemy communities occurring in cotton, however their specific effect on suppressing the cotton aphids (being notorious in conventional cotton ecosystem) has not been fully documented yet. We observed strong evidence for top-down control of the aphid population, e.g. the control efficiency of natural enemies on cotton aphid increased significantly in open field cages compared to exclusion cages, accounted for 60.2, 87.2 and 76.7% in 2011, 2012 and 2013 season, respectively. The cotton aphid populations peaked in early June to late July (early and middle growth stages) in open field cotton survey from 2011 to 2013. The population densities of cotton aphids and natural enemies were highest on middle growth stage while lowest densities were recorded on late stage for aphids and on early plant stage for natural enemies. Aphid parasitoids (Trioxys spp., Aphidius gifuensis), coccinellids and spiders were key natural enemies of cotton aphid. Briefly, natural enemies can suppress aphid population increase from early to middle plant growth stages by providing biocontrol services in Chinese Bt cotton.

  1. Seasonal dynamics of wheat aphid complex and predator Coccinella septempunctata in relation to abiotic and biotic factors.

    PubMed

    Soni, Rajesh; Deol, G S; Singh, Satnam

    2013-07-01

    Seasonal dynamics studies on wheat aphid complex, comprising of four major species and its predator Coccinella septempunctata were conducted in context to abiotic and biotic factors. The alate form of aphids appeared on the crop during the 1st week of December. The colony build up of aphid complex started during the 2nd week of January and peak was observed after the 1st week of March. Wheat aphid complex started declining in the last week of March and disappeared by mid April. The abiotic factors like maximum temperature and evaporation were most important for the build up of aphids. The grubs and adults of C. septempunctata appeared on the crop during mid February and their population increased with the increase in aphid population. The grubs and adult population showed a strong positive correlation with aphid complex. The population of predators had significant positive correlation with maximum, minimum, mean temperature, sunshine and vapour pressure. The population of aphids declined after the 2nd week of March due to the rise in temperature, crop maturity and this in turn resulted in the lowering of the predator population. The studies evaluate in detail the abiotic and biotic factors regulating the wheat aphid complex and C. septempunctata populations under wheat agro-ecosystem.

  2. Characterization of the natural enemy community attacking cotton aphid in the Bt cotton ecosystem in Northern China

    PubMed Central

    Ali, Abid; Desneux, Nicolas; Lu, Yanhui; Liu, Bing; Wu, Kongming

    2016-01-01

    Planting Bt cotton in China since 1997 has led to important changes in the natural enemy communities occurring in cotton, however their specific effect on suppressing the cotton aphids (being notorious in conventional cotton ecosystem) has not been fully documented yet. We observed strong evidence for top-down control of the aphid population, e.g. the control efficiency of natural enemies on cotton aphid increased significantly in open field cages compared to exclusion cages, accounted for 60.2, 87.2 and 76.7% in 2011, 2012 and 2013 season, respectively. The cotton aphid populations peaked in early June to late July (early and middle growth stages) in open field cotton survey from 2011 to 2013. The population densities of cotton aphids and natural enemies were highest on middle growth stage while lowest densities were recorded on late stage for aphids and on early plant stage for natural enemies. Aphid parasitoids (Trioxys spp., Aphidius gifuensis), coccinellids and spiders were key natural enemies of cotton aphid. Briefly, natural enemies can suppress aphid population increase from early to middle plant growth stages by providing biocontrol services in Chinese Bt cotton. PMID:27075171

  3. The Effect of Plant Inbreeding and Stoichiometry on Interactions with Herbivores in Nature: Echinacea angustifolia and Its Specialist Aphid

    PubMed Central

    Wagenius, Stuart; Stanton-Geddes, John; Shaw, Ruth G.

    2011-01-01

    Fragmentation of once widespread communities may alter interspecific interactions by changing genetic composition of interacting populations as well as their abundances and spatial distributions. In a long-term study of a fragmented population of Echinacea angustifolia, a perennial plant native to the North American prairie, we investigated influences on its interaction with a specialist aphid and tending ants. We grew plant progeny of sib-matings (I), and of random pairings within (W) and between (B) seven remnants in a common field within 8 km of the source remnants. During the fifth growing season, we determined each plant's burden of aphids and ants, as well as its size and foliar elemental composition (C, N, P). We also assayed composition (C, N) of aphids and ants. Early in the season, progeny from genotypic classes B and I were twice as likely to harbor aphids, and in greater abundance, than genotypic class W; aphid loads were inversely related to foliar concentration of P and positively related to leaf N and plant size. At the end of the season, aphid loads were indistinguishable among genotypic classes. Ant abundance tracked aphid abundance throughout the season but showed no direct relationship with plant traits. Through its potential to alter the genotypic composition of remnant populations of Echinacea, fragmentation can increase Echinacea's susceptibility to herbivory by its specialist aphid and, in turn, perturb the abundance and distribution of aphids. PMID:21935460

  4. Multiple phytohormone signals control the transcriptional response to soybean aphid infestation in susceptible and resistant soybean plants.

    PubMed

    Studham, Matthew E; MacIntosh, Gustavo C

    2013-01-01

    The soybean aphid (Aphis glycines) is a major phloem-feeding pest of soybean (Glycine max). A. glycines feeding can cause the diversion of photosynthates and transmission of plant viruses, resulting in significant yield losses. In this study, we used oligonucleotide microarrays to characterize the long-term transcriptional response to soybean aphid colonization of two related soybean cultivars, one with the Rag1 aphid-resistance gene and one aphid-susceptible cultivar (without Rag1). Transcriptome profiles were determined after 1 and 7 days of aphid infestation. Our results revealed a susceptible response involving hundreds of transcripts, whereas only one transcript changed in the resistant response to aphids. This nonexistent resistance response might be explained by the fact that many defense-related transcripts are constitutively expressed in resistant plants, whereas these same genes are activated in susceptible plants only during aphid infestation. Analysis of phytohormone-related transcripts in the susceptible response showed different hormone profiles for the two time points, and suggest that aphids are able to suppress hormone signals in susceptible plants. A significant activation of abscissic acid, normally associated with abiotic stress responses, at day 7, might be a decoy strategy implemented by the aphid to suppress effective salicylic acid- and jasmonate-related defenses.

  5. Distinct antimicrobial activities in aphid galls on Pistacia atlantica

    PubMed Central

    Yoram, Gerchman; Inbar, Moseh

    2011-01-01

    Gall-formers are parasitic organisms that manipulate plant traits for their own benefit. Galls have been shown to protect their inhabitants from natural enemies such as predators and parasitoids by various chemical and mechanical means. Much less attention, however, has been given to the possibility of defense against microbial pathogens in the humid and nutrient-rich gall environment. We found that the large, cauliflower-shaped, galls induced by the aphid Slavum wertheimae on buds of Pistacia atlantica trees express antibacterial and antifungal activities distinct from those found in leaves. Antibacterial activity was especially profound against Bacillus spp (a genus of many known insect pathogen) and against Pseudomonas aeruginosa (a known plant pathogen). Antifungal activity was also demonstrated against multiple filamentous fungi. Our results provide evidence for the protective antimicrobial role of galls. This remarkable antibacterial and antifungal activity in the galls of S. wertheimae may be of agricultural and pharmaceutical value. PMID:22105034

  6. How aphids decide what is good for them: experiments to test aphid feeding behaviour on Tanacetum vulgare (L.) using different nitrogen regimes.

    PubMed

    Nowak, Heike; Komor, Ewald

    2010-08-01

    Leaf-chewing herbivores select food with a protein/carbohydrate ratio of 0.8-1.5, whereas phloem sap, which aphids feed on, has a ratio of approximately 0.1. Enhanced N fertilization increases the amino acid concentration in phloem sap and elevates the N/C ratio. The study examines: (1) whether aphids select between plants of different N nutrition, (2) whether feeding time correlates with the amino acid composition of phloem sap, and (3) at which stage of probing aphids identify the quality of the plant. Uroleucon tanaceti (Mordvilko) and Macrosiphoniella tanacetaria (Kaltenbach), specialist aphids feeding on tansy (Tanacetum vulgare L.), were reared on this host plant grown essentially hydroponically (in Vermiculite) in the greenhouse on 1, 3, 6, or 12 mM NH(4)NO(3). One and 3 mM NH(4)NO(3) corresponds to the situation found in natural tansy stands. Aphid stylet penetration was monitored by electrical penetration graphs whilst phloem sap was sampled by stylectomy. Both aphid species settled 2-3 times more frequently on plants fertilized with 6 or 12 mM NH(4)NO(3). The phloem sap of these plants contained up to threefold higher amino acid concentrations, without a change in the proportion of essential amino acids. No time differences were observed before stylet penetration of plant tissue. After the first symplast contact, most aphids penetrated further, except M. tanacetaria on low-N plants, where 50% withdrew the stylet after the first probing. The duration of phloem feeding was 2-3 times longer in N-rich plants and the time spent in individual sieve tubes was up to tenfold longer. Aphids identified the nutritional quality of the host plant mainly by the amino acid concentration of phloem sap, not by leaf surface cues nor the proportion of essential amino acids. However, U. tanaceti infestation increased the percentage of methionine plus tryptophan in phloem tenfold, thus manipulating the plants nutritional quality, and causing premature leaf senescence.

  7. Combined use of 2-D reverse phase chromatography & data independent mass spectrometry simultaneously characterizing proteomes of Schizaphis graminum & its obligate endosymbiont Buchnera aphidicola, from whole aphid extracts

    USDA-ARS?s Scientific Manuscript database

    Understanding the molecular pathways coordinating protein biosynthesis and trafficking by aphids and the involvement of endosymbiont bacterium, Buchnera aphidicola in those processes, is critical to discovering the mechanisms of virus transmission by aphids as well as leveraging that knowledge towar...

  8. Water Stress Modulates Soybean Aphid Performance, Feeding Behavior, and Virus Transmission in Soybean

    PubMed Central

    Nachappa, Punya; Culkin, Christopher T.; Saya, Peter M.; Han, Jinlong; Nalam, Vamsi J.

    2016-01-01

    Little is known about how water stress including drought and flooding modifies the ability of plants to resist simultaneous attack by insect feeding and transmission of insect-vectored pathogen. We analyzed insect population growth, feeding behaviors, virus transmission, and plant amino acid profiles and defense gene expression to characterize mechanisms underlying the interaction between water stress, soybean aphid and aphid-transmitted, Soybean mosaic virus, on soybean plants. Population growth of non-viruliferous aphids was reduced under drought stress and saturation, likely because the aphids spent less time feeding from the sieve element on these plants compared to well-watered plants. Water stress did not impact population growth of viruliferous aphids. However, virus incidence and transmission rate was lowest under drought stress and highest under saturated conditions since viruliferous aphids took the greatest amount time to puncture cells and transmit the virus under saturated conditions and lowest time under drought stress. Petiole exudates from drought-stressed plants had the highest level of total free amino acids including asparagine and valine that are critical for aphid performance. Aphids did not benefit from improved phloem sap quality as indicated by their lower densities on drought-stressed plants. Saturation, on the other hand, resulted in low amino acid content compared to all of the other treatments. Drought and saturation had significant and opposing effects on expression of marker genes involved in abscisic acid (ABA) signaling. Drought alone significantly increased expression of ABA marker genes, which likely led to suppression of salicylic acid (SA)- and jasmonic acid (JA)-related genes. In contrast, ABA marker genes were down-regulated under saturation, while expression of SA- and JA-related genes was up-regulated. We propose that the apparent antagonism between ABA and SA/JA signaling pathways contributed to an increase in aphid

  9. Plant resistance reduces the strength of consumptive and non-consumptive effects of predators on aphids.

    PubMed

    Kersch-Becker, Mônica F; Thaler, Jennifer S

    2015-09-01

    1. The impact of predators on prey has traditionally been attributed to the act of consumption. Prey responses to the presence of the predator (non-consumptive effects), however, can be as important as predation itself. While plant defences are known to influence predator-prey interactions, their relative effects on consumptive vs. non-consumptive effects are not well understood. 2. We evaluated the consequences of plant resistance and predators (Hippodamia convergens) on the mass, number of nymphs, population growth, density and dispersal of aphids (Macrosiphum euphorbiae). We tested for the effects of plant resistance on non-consumptive and consumptive effects of predators on aphid performance and dispersal using a combination of path analysis and experimental manipulation of predation risk. 3. We manipulated plant resistance using genetically modified lines of tomato (Solanum lycopersicum) that vary incrementally in the expression of the jasmonate pathway, which mediates induced resistance to insects and manipulated aphid exposure to lethal and risk predators. Predation risk predators had mandibles impaired to prevent killing. 4. Plant resistance reduced predation rate (consumptive effect) on high resistance plants. As a consequence, predators had no impact on the number of nymphs, aphid density or population growth on high resistance plants, whereas on low resistance plants, predators reduced aphid density by 35% and population growth by 86%. Path analysis and direct manipulation of predation risk showed that predation risk rather than predation rate promoted aphid dispersal and varied with host plant resistance. Aphid dispersal in response to predation risk was greater on low compared to high resistance plants. The predation risk experiment also showed that the number of aphid nymphs increased in the presence of risk predators but did not translate into increased population growth. 5. In conclusion, the consumptive and non-consumptive components of predators

  10. Shallot Aphids, Myzus ascalonicus, in Strawberry: Biocontrol Potential of Three Predators and Three Parasitoids

    PubMed Central

    Enkegaard, Annie; Sigsgaard, Lene; Kristensen, Kristian

    2013-01-01

    The parasitization capacity of 3 parasitoids and the predation capacity of 3 predators towards the shallot aphid, Myzus ascalonicus Doncaster (Homoptera: Aphididae), on strawberry, Fragaria x ananassa Duchesne (Rosales: Rosaceae) cv. Honeoye, were examined in laboratory experiments. In Petri dish assays, both Aphidius colemani Viereck (Hymenoptera: Aphidiidae) and A. ervi Haliday readily stung shallot aphids, with no significant difference in stinging frequency between the two species. A. ervi induced a significantly higher mortality (79.0 ± 7.2%) in terms of stung aphids compared with A. colemani (55.3 ± 4.1%); however, only a minor fraction (2.7 ± 1.8% and 7.1 ± 3.1%, respectively) of the killed aphids resulted in formation of mummies, presumably due to a physiological response to parasitism. The low percentage of mummification precludes the use of either Aphidius species in anything but inundative biocontrol. In similar set-ups, Aphelinus abdominalis (Dalman) (Hymenoptera: Aphelinidae) killed almost half (49.6 ± 5.3%) of the exposed aphids through host feeding. In addition, 23.2 ± 7.3% of non-host-fed aphids developed into mummified aphids, and 38.1 ± 13.2% of non-host-fed aphids died from other parasitoid-induced causes. However, the host feeding rate was reduced to only 1.2 ± 0.8%, and no significant parasitization mortality was observed on strawberry plants, suggesting that host plants interfered with A. abdominalis activity. This parasitoid does not, therefore, seem to be suited to either inoculative or inundative biocontrol of shallot aphids in strawberry. The three predators studied were the green lacewing, Chrysoperla carnea Steph. (Neuroptera: Chrysopidae), the two-spotted lady beetle, Adalia bipunctata L. (Coleoptera: Coccinellidae), and the gall midge Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae). Third instars of all 3 predators readily preyed upon the shallot aphid in Petri dish set-ups with significant differences in daily

  11. Shallot aphids, Myzus ascalonicus, in strawberry: biocontrol potential of three predators and three parasitoids.

    PubMed

    Enkegaard, Annie; Sigsgaard, Lene; Kristensen, Kristian

    2013-01-01

    The parasitization capacity of 3 parasitoids and the predation capacity of 3 predators towards the shallot aphid, Myzus ascalonicus Doncaster (Homoptera: Aphididae), on strawberry, Fragaria x ananassa Duchesne (Rosales: Rosaceae) cv. Honeoye, were examined in laboratory experiments. In Petri dish assays, both Aphidius colemani Viereck (Hymenoptera: Aphidiidae) and A. ervi Haliday readily stung shallot aphids, with no significant difference in stinging frequency between the two species. A. ervi induced a significantly higher mortality (79.0 ± 7.2%) in terms of stung aphids compared with A. colemani (55.3 ± 4.1%); however, only a minor fraction (2.7 ± 1.8% and 7.1 ± 3.1%, respectively) of the killed aphids resulted in formation of mummies, presumably due to a physiological response to parasitism. The low percentage of mummification precludes the use of either Aphidius species in anything but inundative biocontrol. In similar set-ups, Aphelinus abdominalis (Dalman) (Hymenoptera: Aphelinidae) killed almost half (49.6 ± 5.3%) of the exposed aphids through host feeding. In addition, 23.2 ± 7.3% of non-host-fed aphids developed into mummified aphids, and 38.1 ± 13.2% of non-host-fed aphids died from other parasitoid-induced causes. However, the host feeding rate was reduced to only 1.2 ± 0.8%, and no significant parasitization mortality was observed on strawberry plants, suggesting that host plants interfered with A. abdominalis activity. This parasitoid does not, therefore, seem to be suited to either inoculative or inundative biocontrol of shallot aphids in strawberry. The three predators studied were the green lacewing, Chrysoperla carnea Steph. (Neuroptera: Chrysopidae), the two-spotted lady beetle, Adalia bipunctata L. (Coleoptera: Coccinellidae), and the gall midge Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae). Third instars of all 3 predators readily preyed upon the shallot aphid in Petri dish set-ups with significant differences in daily

  12. The ethylene response factor Pti5 contributes to potato aphid resistance in tomato independent of ethylene signalling

    PubMed Central

    Wu, Chengjun; Avila, Carlos A.; Goggin, Fiona L.

    2015-01-01

    Ethylene response factors (ERFs) comprise a large family of transcription factors that regulate numerous biological processes including growth, development, and response to environmental stresses. Here, we report that Pti5, an ERF in tomato [Solanum lycopersicum (Linnaeus)] was transcriptionally upregulated in response to the potato aphid Macrosiphum euphorbiae (Thomas), and contributed to plant defences that limited the population growth of this phloem-feeding insect. Virus-induced gene silencing of Pti5 enhanced aphid population growth on tomato, both on an aphid-susceptible cultivar and on a near-isogenic genotype that carried the Mi-1.2 resistance (R) gene. These results indicate that Pti5 contributes to basal resistance in susceptible plants and also can synergize with other R gene-mediated defences to limit aphid survival and reproduction. Although Pti5 contains the ERF motif, induction of this gene by aphids was independent of ethylene, since the ACC deaminase (ACD) transgene, which inhibits ethylene synthesis, did not diminish the responsiveness of Pti5 to aphid infestation. Furthermore, experiments with inhibitors of ethylene synthesis revealed that Pti5 and ethylene have distinctly different roles in plant responses to aphids. Whereas Pti5 contributed to antibiotic plant defences that limited aphid survival and reproduction on both resistant (Mi-1.2+) and susceptible (Mi-1.2–) genotypes, ethylene signalling promoted aphid infestation on susceptible plants but contributed to antixenotic defences that deterred the early stages of aphid host selection on resistant plants. These findings suggest that the antixenotic defences that inhibit aphid settling and the antibiotic defences that depress fecundity and promote mortality are regulated through different signalling pathways. PMID:25504643

  13. Quantitative differences in aphid virulence and foliar symptom development on tomato plants carrying the Mi resistance gene.

    PubMed

    Hebert, Stephanie L; Jia, Lingling; Goggin, Fiona L

    2007-04-01

    The Mi resistance gene in tomato reduces the feeding, fecundity, and survival of certain isolates of the potato aphid (Macrosiphum euphorbiae Thomas). This study compared the performance of two potato aphid isolates, WU11 and WU12, on nearly isogenic susceptible (Mi-) and resistant (Mi+) tomato cultivars. Although Mi significantly reduced the population growth of both aphids, WU12 numbers decreased by only 15% compared with 95% for isolate WU11. These results show that there are quantitative differences in virulence among potato aphid isolates. Compared with WU11 aphids, isolate WU12 caused more necrosis on both resistant and susceptible plants, and this increased damage may play a role in the partial virulence of isolate WU12. However, infestation with aphid isolate WU12 did not compromise plant defenses against isolate WU11 in resistant plants. Prior inoculation with either aphid isolate caused a modest reduction in the survival of WU12 adults, but this form of induced resistance was observed on both resistant and susceptible cultivars. Thus, Mi did not play a role in acquired resistance or mediate any indirect interactions between the two aphid isolates. Notably, the mode of action of Mi-mediated resistance seemed to differ depending on the aphid isolate tested. Mi dramatically deterred feeding by WU11 aphids, whereas the effects of resistance on isolate WU12 seemed to be caused primarily by antibiosis. Tolerance did not seem to be a major component of Mi-mediated responses, although resistant plants showed a modest reduction in the amount of foliar necrosis induced per aphid compared with susceptible plants.

  14. The physiology of sterol nutrition in the pea aphid Acyrthosiphon pisum.

    PubMed

    Bouvaine, Sophie; T Behmer, Spencer; Lin, George G; Faure, Marie-Line; Grebenok, Robert J; Douglas, Angela E

    2012-11-01

    The phloem sap of fava bean (Vicia faba) plants utilized by the pea aphid Acyrthosiphon pisum contains three sterols, cholesterol, stigmasterol and sitosterol, in a 2:2:1 ratio. To investigate the nutritional value of these sterols, pea aphids were reared on chemically-defined diets containing each sterol at 0.1, 1 and 10μgml(-1) with a sterol-free diet as control. Larval growth rate and aphid lifespan did not vary significantly across the diets, indicating that sterol reserves can buffer some performance indices against a shortfall in dietary sterol over at least one generation. However, lifetime reproductive output was depressed in aphids on diets containing stigmasterol or no sterol, relative to diets supplemented with cholesterol or sitosterol. The cholesterol density of embryos in teneral adults was significantly higher than in the total body; and the number and biomass of embryos in aphids on diets with stigmasterol and no sterols were reduced relative to diets with cholesterol or sitosterol, indicating that the reproductive output of the pea aphid can be limited by the amount and composition of dietary sterol. In a complementary RNA-seq analysis of pea aphids reared on plants and diets with different sterol contents, 7.6% of the 17,417 detected gene transcripts were differentially expressed. Transcript abundance of genes with annotated function in sterol utilization did not vary significantly among treatments, suggesting that the metabolic response to dietary sterol may be mediated primarily at the level of enzyme function or metabolite concentration. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Pest control of aphids depends on landscape complexity and natural enemy interactions.

    PubMed

    Martin, Emily A; Reineking, Björn; Seo, Bumsuk; Steffan-Dewenter, Ingolf

    2015-01-01

    Aphids are a major concern in agricultural crops worldwide, and control by natural enemies is an essential component of the ecological intensification of agriculture. Although the complexity of agricultural landscapes is known to influence natural enemies of pests, few studies have measured the degree of pest control by different enemy guilds across gradients in landscape complexity. Here, we use multiple natural-enemy exclosures replicated in 18 fields across a gradient in landscape complexity to investigate (1) the strength of natural pest control across landscapes, measured as the difference between pest pressure in the presence and in the absence of natural enemies; (2) the differential contributions of natural enemy guilds to pest control, and the nature of their interactions across landscapes. We show that natural pest control of aphids increased up to six-fold from simple to complex landscapes. In the absence of pest control, aphid population growth was higher in complex than simple landscapes, but was reduced by natural enemies to similar growth rates across all landscapes. The effects of enemy guilds were landscape-dependent. Particularly in complex landscapes, total pest control was supplied by the combined contribution of flying insects and ground-dwellers. Birds had little overall impact on aphid control. Despite evidence for intraguild predation of flying insects by ground-dwellers and birds, the overall effect of enemy guilds on aphid control was complementary. Understanding pest control services at large spatial scales is critical to increase the success of ecological intensification schemes. Our results suggest that, where aphids are the main pest of concern, interactions between natural enemies are largely complementary and lead to a strongly positive effect of landscape complexity on pest control. Increasing the availability of seminatural habitats in agricultural landscapes may thus benefit not only natural enemies, but also the effectiveness of

  16. Pest control of aphids depends on landscape complexity and natural enemy interactions

    PubMed Central

    Reineking, Björn; Seo, Bumsuk; Steffan-Dewenter, Ingolf

    2015-01-01

    Aphids are a major concern in agricultural crops worldwide, and control by natural enemies is an essential component of the ecological intensification of agriculture. Although the complexity of agricultural landscapes is known to influence natural enemies of pests, few studies have measured the degree of pest control by different enemy guilds across gradients in landscape complexity. Here, we use multiple natural-enemy exclosures replicated in 18 fields across a gradient in landscape complexity to investigate (1) the strength of natural pest control across landscapes, measured as the difference between pest pressure in the presence and in the absence of natural enemies; (2) the differential contributions of natural enemy guilds to pest control, and the nature of their interactions across landscapes. We show that natural pest control of aphids increased up to six-fold from simple to complex landscapes. In the absence of pest control, aphid population growth was higher in complex than simple landscapes, but was reduced by natural enemies to similar growth rates across all landscapes. The effects of enemy guilds were landscape-dependent. Particularly in complex landscapes, total pest control was supplied by the combined contribution of flying insects and ground-dwellers. Birds had little overall impact on aphid control. Despite evidence for intraguild predation of flying insects by ground-dwellers and birds, the overall effect of enemy guilds on aphid control was complementary. Understanding pest control services at large spatial scales is critical to increase the success of ecological intensification schemes. Our results suggest that, where aphids are the main pest of concern, interactions between natural enemies are largely complementary and lead to a strongly positive effect of landscape complexity on pest control. Increasing the availability of seminatural habitats in agricultural landscapes may thus benefit not only natural enemies, but also the effectiveness of

  17. Selective and Irreversible Inhibitors of Aphid Acetylcholinesterases: Steps Toward Human-Safe Insecticides

    PubMed Central

    Pang, Yuan-Ping; Singh, Sanjay K.; Gao, Yang; Lassiter, T. Leon; Mishra, Rajesh K.; Zhu, Kun Yan; Brimijoin, Stephen

    2009-01-01

    Aphids, among the most destructive insects to world agriculture, are mainly controlled by organophosphate insecticides that disable the catalytic serine residue of acetylcholinesterase (AChE). Because these agents also affect vertebrate AChEs, they are toxic to non-target species including humans and birds. We previously reported that a cysteine residue (Cys), found at the AChE active site in aphids and other insects but not mammals, might serve as a target for insect-selective pesticides. However, aphids have two different AChEs (termed AP and AO), and only AP-AChE carries the unique Cys. The absence of the active-site Cys in AO-AChE might raise concerns about the utility of targeting that residue. Herein we report the development of a methanethiosulfonate-containing small molecule that, at 6.0 µM, irreversibly inhibits 99% of all AChE activity extracted from the greenbug aphid (Schizaphis graminum) without any measurable inhibition of the human AChE. Reactivation studies using β-mercaptoethanol confirm that the irreversible inhibition resulted from the conjugation of the inhibitor to the unique Cys. These results suggest that AO-AChE does not contribute significantly to the overall AChE activity in aphids, thus offering new insight into the relative functional importance of the two insect AChEs. More importantly, by demonstrating that the Cys-targeting inhibitor can abolish AChE activity in aphids, we can conclude that the unique Cys may be a viable target for species-selective agents to control aphids without causing human toxicity and resistance problems. PMID:19194505

  18. How does the host-specialized aphid deal with food deficiency?

    PubMed

    Xu, Ting-Ting; Ma, Ting-Ting; Liu, Xiang-Dong

    2014-06-01

    Aphis gossypii Glover shows obvious host specialization, with cucurbit- and cotton-specialized biotypes or host races in many regions. Because its annual natal host crops senesce earlier the cucurbit-specialized biotype may suffer food deficiency. The method this biotype uses to overcome this challenge is still poorly understood. In order to understand the potential of the cucurbit-specialized biotype aphids in host shift and usage, the performance of this biotype on cotton (Gossypium hirsutum), a common but poor quality host plant, was explored in this study. The cucurbit-specialized aphids could establish populations on cotton only when these plants had at least nine leaves, and subsequent populations developed rather slowly. The presence of whitefly populations on cotton improved the success rate of cucurbit-specialized aphids. The cucurbit-specialized aphids were mainly distributed on the older leaves of cotton, with only a few settling on the upper leaves. The cucurbit-specialized aphids reared on cotton for 40, 54 and 61 days still maintained strong preference for their natal host plant, cucumber (Cucumis sativus), rather than cotton, and their net reproductive rates and intrinsic rates of natural increase were dramatically lower when they were transferred onto new six-leaf cotton plants or detached leaves. Therefore, we concluded that the cucurbit-specialized aphids have the potential to utilize mature or whitefly-stressed cotton plants, but that this feeding experience on cotton did not alter their specialization for cucurbits. Some cotton plants could act as a temporary host for the cucurbit-specialized aphids to overcome food deficiency arising from senescing cucurbits.

  19. Deciphering the Function of Octopaminergic Signaling on Wing Polyphenism of the Pea Aphid Acyrthosiphon pisum

    PubMed Central

    Wang, Xing-Xing; Zhang, Yi; Zhang, Zhan-Feng; Tian, Hong-Gang; Liu, Tong-Xian

    2016-01-01

    Aphids exhibit wing polyphenism (winged or wingless) for adaption to predictable or temporally heterogeneous environmental changes; however, the underlying mechanism is still unclear. This morphological change could be stimulated by high aphid density, which in turn could affect octopaminergic signaling in aphids. Octopamine is a neurotransmitter synthesized in insects that can modify their physiological metabolism, locomotion, and other behaviors. We designed experiments to determine whether octopamine functions in wing formation of the pea aphid, Acyrthosiphon pisum (Harris). We determined gene expression of tyramine β-hydroxylase (TβH), a key enzyme in octopamine synthesis at different developmental stages, in different body parts, and in different densities of aphids. We also used TβH RNAi, octopamine receptor agonists (octopamine and synephrine), and an antagonist (mianserin) to modify octopaminergic signaling. We found that transcription of TβH was related to aphid density, which affected the proportion of winged offspring. By manually modifying the mother's octopaminergic signaling, TβH expression was suppressed, and TβH (enzyme) activity decreased. The proportion of winged offspring was also affected. Our results showed that octopamine could be a link in the wing determination system, as well as environmental stimulation. The RNAi results showed that the decrease of TβH expression increased aphid's reproduction; however, the decrease of TβH expression declined the numbers of winged-offspring producers, but did not affect the proportion of winged nymphs produced by the winged-offspring producer. In conclusion, the decline in the proportion of winged daughters in the next generation was caused by the decline of winged nymph producers. PMID:28018234

  20. Aphid Wing Induction and Ecological Costs of Alarm Pheromone Emission under Field Conditions

    PubMed Central

    Hatano, Eduardo; Kunert, Grit; Weisser, Wolfgang W.

    2010-01-01

    The pea aphid, Acyrthosiphon pisum Harris, (Homoptera: Aphididae) releases the volatile sesquiterpene (E)-β-farnesene (EBF) when attacked by a predator, triggering escape responses in the aphid colony. Recently, it was shown that this alarm pheromone also mediates the production of the winged dispersal morph under laboratory conditions. The present work tested the wing-inducing effect of EBF under field conditions. Aphid colonies were exposed to two treatments (control and EBF) and tested in two different environmental conditions (field and laboratory). As in previous experiments aphids produced higher proportion of winged morphs among their offspring when exposed to EBF in the laboratory but even under field conditions the proportion of winged offspring was higher after EBF application (6.84±0.98%) compared to the hexane control (1.54±0.25%). In the field, the proportion of adult aphids found on the plant at the end of the experiment was lower in the EBF treatment (58.1±5.5%) than in the control (66.9±4.6%), in contrast to the climate chamber test where the numbers of adult aphids found on the plant at the end of the experiment were, in both treatments, similar to the numbers put on the plant initially. Our results show that the role of EBF in aphid wing induction is also apparent under field conditions and they may indicate a potential cost of EBF emission. They also emphasize the importance of investigating the ecological role of induced defences under field conditions. PMID:20585639

  1. Seasonal Phenology and Species Composition of the Aphid Fauna in a Northern Crop Production Area

    PubMed Central

    Kirchner, Sascha M.; Hiltunen, Lea; Döring, Thomas F.; Virtanen, Elina; Palohuhta, Jukka P.; Valkonen, Jari P. T.

    2013-01-01

    Background The species diversity of aphids and seasonal timing of their flight activity can have significant impacts on crop production, as aphid species differ in their ability to transmit plant viruses and flight timing affects virus epidemiology. The aim of the study was to characterise the species composition and phenology of aphid fauna in Finland in one of the northernmost intensive crop production areas of the world (latitude 64°). Methodology/Principal Findings Flight activity was monitored in four growing seasons (2007–010) using yellow pan traps (YPTs) placed in 4–8 seed potato fields and a Rothamsted suction trap. A total of 58,528 winged aphids were obtained, identified to 83 taxa based on morphology, and 34 species were additionally characterised by DNA barcoding. Seasonal flight activity patterns analysed based on YPT catch fell into three main phenology clusters. Monoecious taxa showed early or middle-season flight activity and belonged to species living on shrubs/trees or herbaceous plants, respectively. Heteroecious taxa occurred over the entire potato growing season (ca. 90 days). Abundance of aphids followed a clear 3-year cycle based on suction trap data covering a decade. Rhopalosiphum padi occurring at the end of the potato growing season was the most abundant species. The flight activity of Aphis fabae, the main vector of Potato virus Y in the region, and Aphis gossypii peaked in the beginning of potato growing season. Conclusions/Significance Detailed information was obtained on phenology of a large number aphid species, of which many are agriculturally important pests acting as vectors of plant viruses. Aphis gossypii is known as a pest in greenhouses, but our study shows that it occurs also in the field, even far in the north. The novel information on aphid phenology and ecology has wide implications for prospective pest management, particularly in light of climate change. PMID:23967149

  2. Fuel-air control device

    SciTech Connect

    Norman, J.

    1981-12-15

    The invention concerns a device for controlling the vehicles fuel-air mixture by regulating the air in the ventilation passage leading to the engine air intake from the crankcase. In a vehicle provided with a PCV valve, the device is located in the ventilation passage leading from the crankcase to the engine air intake and the device is downstream of the PCV valve. The device admits outside air to the ventilation passage to lean the gas mixture when the engine creates a vacuum less than 8 psi in the ventilation passage.

  3. Development of genic-SSR markers from soybean aphid sequences generated by high-throughput sequencing of cDNA library

    USDA-ARS?s Scientific Manuscript database

    The soybean aphid (Aphis glycines Matsumura) is the most important insect pest of soybean [Glycine max (L.) Merr.] in North America and three biotypes of the aphid have been confirmed. Knowledge of aphid population genetics is needed for deployment of host-plant resistance and other control measures...

  4. Toxicity of newly isolated piperideine alkaloids from the red imported fire ant, Solenopsis invicta Buren, against the green peach aphid, Myzus persicae (Sulzer)

    USDA-ARS?s Scientific Manuscript database

    The green peach aphid, Myzus persicae (Sulzer), is a major insect pest of many agronomic and horticultural crops and is distributed worldwide Aphid management is often based on application of insecticides. However, the aphid is now resistant to many of these and much interest has recently develope...

  5. A protein from the salivary glands of the pea aphid, Acyrthosiphon pisum, is essential in feeding on a host plant

    PubMed Central

    Mutti, Navdeep S.; Louis, Joe; Pappan, Loretta K.; Pappan, Kirk; Begum, Khurshida; Chen, Ming-Shun; Park, Yoonseong; Dittmer, Neal; Marshall, Jeremy; Reese, John C.; Reeck, Gerald R.

    2008-01-01

    In feeding, aphids inject saliva into plant tissues, gaining access to phloem sap and eliciting (and sometimes overcoming) plant responses. We are examining the involvement, in this aphid–plant interaction, of individual aphid proteins and enzymes, as identified in a salivary gland cDNA library. Here, we focus on a salivary protein we have arbitrarily designated Protein C002. We have shown, by using RNAi-based transcript knockdown, that this protein is important in the survival of the pea aphid (Acyrthosiphon pisum) on fava bean, a host plant. Here, we further characterize the protein, its transcript, and its gene, and we study the feeding process of knockdown aphids. The encoded protein fails to match any protein outside of the family Aphididae. By using in situ hybridization and immunohistochemistry, the transcript and the protein were localized to a subset of secretory cells in principal salivary glands. Protein C002, whose sequence contains an N-terminal secretion signal, is injected into the host plant during aphid feeding. By using the electrical penetration graph method on c002-knockdown aphids, we find that the knockdown affects several aspects of foraging and feeding, with the result that the c002-knockdown aphids spend very little time in contact with phloem sap in sieve elements. Thus, we infer that Protein C002 is crucial in the feeding of the pea aphid on fava bean. PMID:18621720

  6. Using multispectral imagery to compare the spatial pattern of injury to wheat caused by Russian wheat aphid and greenbug

    USDA-ARS?s Scientific Manuscript database

    The Russian wheat aphid, Diuraphis noxia (Mordvilko), and greenbug, Schizaphis graminum (Rondani), are important aphid pests of wheat. Outbreaks of both pests in commercial wheat fields occur almost every year in the Great Plains of the United States. Infestations of both pests in wheat fields are...

  7. Disruption of web structure and predatory behavior of a spider by plant-derived chemical defenses of an aposematic aphid.

    PubMed

    Malcolm, S B

    1989-06-01

    Two toxic and bitter-tasting cardenolides (cardiac-active steroids) were sequestered by the brightly colored oleander aphid,Aphis nerii B. de F., from the neotropical milkweed host plantAsclepias curassavica L. After feeding on milkweed-reared aphids, the orb-web spiderZygiella x-notata (Clerck) built severely disrupted webs and attacked fewer nontoxic, control aphids, whereas the webs of spiders fed only nontoxic aphids remained intact. The regularity and size of the prey-trapping area of webs were reduced significantly in proportion to the amount of toxic aphids eaten. The effects of toxic aphids on spider web structure were mimicked by feeding spiders the bitter-tasting cardenolide digitoxin, a cardenolide with similar steroidal structure and pharmacological activity to the two aphid cardenolides. These results show that the well-known effects of psychoactive drugs on spider web structure are more than interesting behavioral assays of drag activity. Similar effects, produced by plant-derived chemicals in the spider's aphid prey, are relevant to the ecology and evolution of interactions between prey defense and predator foraging.

  8. Genetic population structure of sugarcane aphid, Melanaphis sacchari, in sorghum, sugarcane, and Johnsongrass in the continental USA

    USDA-ARS?s Scientific Manuscript database

    In 2013, an outbreak of Melanaphis sacchari, the sugarcane aphid, was reported in sorghum in Texas. Although this aphid has been reported in the continental U.S. since the 1920s, its occurrence was limited to Florida and Louisiana sugarcane. In just two years M. sacchari has been reported in almos...

  9. Resistance to lettuce aphid (Nasonovia ribisnigri) biotype 0 in wild lettuce accessions PI 491093 and PI 274378

    USDA-ARS?s Scientific Manuscript database

    Lettuce aphid, Nasonovia ribisnigri Mosley (Homoptera : Aphididae), is a major insect pest of lettuce, Lactuca sativa L, in many commercial lettuce productions areas around the world. Resistance to lettuce aphid was first reported in Lactuca virosa L. accession IVT 280 and characterized as complete,...

  10. Attraction of the tea aphid, toxoptera aurantii, attraction to combinations of volatiles and colors related to tea plants

    USDA-ARS?s Scientific Manuscript database

    The tea aphid, Toxoptera aurantii Boyer (Homoptera: Aphididae), is a major pest of the tea plant, Camellia sinensis. Fourteen volatile compounds were identified by GC-MS from air passed over intact tea shoots (ITSV). Electrophysiological and behavioral responses of the winged tea aphids to ITSV as w...

  11. Resistance of Endophyte-Infected Plants of Tall Fescue and Perennial Ryegrass to the Russian Wheat Aphid (Homoptera: Aphididae)

    Treesearch

    S.L. Clement; K.S. Pike; W.J. Kaiser; A. Dan Wilson

    1991-01-01

    Fewer aphids of the Russian wheat aphid, (Mordvilko), were found on tall fescue and perennial ryegrass plants harboring systemic fungal endophytes than on endophyte-free plants in laboratory tests. These results indicate that enhanced resistance in some perennial grasses to D. noxia is associated with the presence of endophytic fungi.

  12. Invertebrate communities in spring wheat and the identification of cereal aphid predators through molecular gut content analysis

    USDA-ARS?s Scientific Manuscript database

    Cereal aphid complexes are responsible for reducing wheat production worldwide; however, management against these species is rare in North America. Generalist predators may contribute to reducing cereal aphid numbers and preventing significant damage to crops. A two-year survey identifying the arth...

  13. Mutualistic and antagonistic trophic interactions in canola: the role of aphids in shaping pest and predator