MULTI-TROPHIC INTERACTIONS AMONG APHID PARASITOIDS

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0227154
• Project Start Date: Oct 1, 2011
• Project End Date: Sep 30, 2015
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIV OF HAWAII
3190 MAILE WAY
HONOLULU,HI 96822

Performing Department
Plant & Environmental Protection Sciences

Non Technical Summary
Indirect effects of biological control can be difficult to measure and hard to predict, but their evaluation is a necessary part of risk analyses for new species introductions. Data on indirect interactions among parasitoids in the field are particularly hard to obtain, because conventional rearing and dissection methods often yield inadequate information due to high mortality. New techniques using molecular markers can rapidly and accurately identify parasitoid species, even in the egg or larval stage within their hosts, and can provide information unavailable using current methods. We will develop molecular diagnostic tools to determine whether competition and hyper-parasitism interfere with the success of biological control of invasive aphid pests in Hawaii, and will use this information to address regulatory concerns and improve the process of parasitoid introductions.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
215	1099	1130	100%

Knowledge Area
215 - Biological Control of Pests Affecting Plants;

Subject Of Investigation
1099 - Tropical/subtropical fruit, general/other;

Field Of Science
1130 - Entomology and acarology;

Keywords

aphid

parasitoid

hyperparasitoid

biological control

binodoxys communis

multiplex pcr

invasive species

Goals / Objectives
1.Sequence the DNA of at least three genes or gene regions from voucher specimens of aphid parasitoids and hyper-parasitoids previously introduced to Hawaii, followed by the development of molecular diagnostic tools for identification of selected species. 2.Determine outcome of competitive interactions among aphid parasitoids belonging to 3 different families (Aphelinidae, Braconidae, Cecidomyiidae) in laboratory experiments. 3.Using the molecular diagnostic tools developed, identify the parasitoid complex associated with aphids from a variety of locations and crop plants in Hawaii, and characterize inter-specific trophic interactions among parasitoids and hyper-parasitoids sharing the same host species. 4.Assess the establishment and impact of Binodoxys communis, a newly introduced aphid parasitoid released in Hawaii vegetable and taro fields.

Project Methods
A multiplex PCR assay will be developed for aphid primary and secondary parasitoid species in Hawaii. Sequences will be analyzed, and regions with consistent sequence differences will be used to design species specific primers for each species. Each primer set will be designed to amplify a unique fragment size, thereby allowing these primers to be used in multiplex PCR when possible. Primer sensitivity and specificity will be evaluated to ensure their utility in subsequent experiments. Colonies of host aphids and selected parasitoid species will be established and maintained in the greenhouse and laboratory. Experiments on multi-parasitism by different combinations of parasitoid species will be conducted in the lab. In a Petri dish, aphids parasitized by one species of parasitoid (species A) will be exposed to a second species of parasitoid (species B). Attack and oviposition will be observed, and paired samples of parasitized individuals will be examined by rearing and molecular methods to assess the outcome of the competition. Aphids (primarily Aphis gossypii and Pentalonia nigronervosa) will be collected from multiple crop host plants on Kauai, Hawaii, and Oahu. DNA from individual aphids in each collection will be extracted and amplified. Analysis using the multiplex PCR assay will be used to determine the level of multi and hyperparasitism in field populations. Binodoxys communis will be released into aphid-infested fields. Weekly sampling will determine percent parasitism of the aphids by the new species, and the percent of multiparasitism and hyperparasitism that occurs in the field. Results from rearing, dissection, and DNA analysis will be compared

Progress 10/01/11 to 09/30/15

Outputs
Target Audience:Improved biological and/or chemical control of aphids will benefit all farmers who grow crops attacked by these pest species. Aphids infest a wide range of commodities including bananas, cucurbit crops (melons, squash, cucumber, pumpkin); tree fruits (avocado, citrus, guava, papaya, mango); and vegetables (eggplant, tomato, peppers, etc). The State and Federal agencies that take part in aphid control programs (including USDA-ARS, USDA-APHIS, Hawaii Dept. of Agriculture, Hawaii Invasive Species Council, and others) will find the outcomes of this work useful in conducting risk analyses. This work will also be of interest and usefulness to conservationists and organizations that are focused on protecting native species and the preservation of the endemic flora of the Hawaiian Islands. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Ms. Angelita Acebes, former graduate student at the University of Hawaii, currently graduate student at Virginia Tech University. Through experience working on this project Ms. Acebes was successful in obtaining her Master's degree; she won several prizes for the presentation of her research results at conferences. Taro farmers Clayton Ueno (Hanapepe) and Wayne Tanji (Hanalei) allowed us to use their farms, and interacted with us on a weekly basis during the research to understand aphid biology and dynamics. How have the results been disseminated to communities of interest?Publications and presentations at meetings and symposia. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Contrary to expectations, we found that B. communis was susceptible to S.aphidovorus attack, but A. colemani was a more suitable host, as shown by higher rates of hyperparasitism when both parasitoid species were exposed simultaneously, and a more female-biased sex ratio of hyperparasitoids emerging from A. colemani mummies. The higher suitability of Aphidius colemani for hyperparasitoid development is likely influenced by its larger size, implying more resources for the hyperparasitoids. No evidence of apparent competition (in terms of the hyperparasitoid's host finding ability or host suitability) was found to be comparatively more unfavorable towards B. communis. This may have positive implications for B. communis establishment and efficacy in the long run. Although temporary establishment of a new aphid parasitoid (Binodoxys communis) was achieved, parasitoid populations remained low, and eventually declined below detection levels. Longer term establishment appears doubtful. We can attribute this in part to the heavy impact of hyperparasitoids attacking all primary parasitoids in the taro and cucumber systems, facilitated by apparent competition between Aphidius colemani and B. communis. Use of molecular markers allowed us to detect multi hyper-parasitism and hyper-parasitism of live aphids, which were not previously known from this system. Follow-up surveys of three taro fields where the introduced parasitoid Binodoxys communis was released showed that the wasp no longer can be found, and is considered locally extinct after temporary establishment. Preliminary investigations were made into the potential of using an alternate (extant) parasitoid for improved biocontrol of Aphis gossypii.

Publications

• Type: Journal Articles Status: Published Year Published: 2013 Citation: Messing, R.H., Pike, K.S., and Foottit, R.G. 2012. Invasive Aphids in Hawaii. Honolulu: College of Tropical Agriculture and Human Resources, University of Hawaii, 261 pp.
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Acebes, A.L. and Messing, R.H. 2013. Host range of a newly introduced parasitoid, Binodoxys communis (Gahan) among common aphid species in Hawaii. BioControl 58: 635-644.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Benelli, G.G., Kavallieratos, N.G., Donati, E., Mencattelli, M., Bonsignori, G., Stefanini, C., Canale, A., and Messing, R.H. 2014. May the wild male loose? Male wing fanning performance and mating success in wild and mass-reared strains of the aphid parasitoid Aphidius colemani Viereck. BioControl 59:487500.

Progress 10/01/13 to 09/30/14

Outputs
Target Audience: Farmers whose crops are impacted by aphid pests in Hawaii. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Publication in peer reviewed journal. What do you plan to do during the next reporting period to accomplish the goals? More detailed review of the ethology of Aphidius colemani and potential for enhanced biocontrol.

Impacts
What was accomplished under these goals? Follow-up surveys of three taro fields where the introduced parasitoid Binodoxys communis was released showed that the wasp no longer can be found, and is considered locally extinct after temporary establishment. Preliminary investigations were made into the potential of using an alternate (extant) parasitoid for improved biocontrol of Aphis gossypii.

Publications

• Type: Journal Articles Status: Published Year Published: 2014 Citation: Benelli, G.G., Kavallieratos, N.G., Donati, E., Mencattelli, M., Bonsignori, G., Stefanini, C., Canale, A., and Messing, R.H. 2014. May the wild male loose? Male wing fanning performance and mating success in wild and mass-reared strains of the aphid parasitoid Aphidius colemani Viereck. BioControl 59:487500.

Progress 10/01/12 to 09/30/13

Outputs
Target Audience: All farmers in Hawaii that have exotic invasive aphids attacking their crops. This includes amost all agricutlral commodities grown in the state. Addiaional target audiences include other scientists and extension agents that interact with farmers and that study pest management and biological control. Changes/Problems: Funding is being sought for more detailed investigation with sufficient replication and sample sizes. What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? We have had one-on-one discussions with taro farmers, and have presented research results at meetings. What do you plan to do during the next reporting period to accomplish the goals? Conduct follow-up sampling of three taro fields on Kauai island; rear aphid mummies to determine primary and hyper parasitoid community dynamics.

Impacts
What was accomplished under these goals? Although temporary establishment of a new aphid parasitoid (Binodoxys communis) was achieved, parasitoid populations remained low, and eventually declined below detection levels. Longer term establishment appears doubtful. We can attribute this in part to the heavy impact of hyperparasitoids attacking all primary parasitoids in the taro and cucumber systems, facilitated by apparent competition between Aphidius colemani and B. communis. USe of molecular markers allowed us to detect multi-hyper-parasitism and hyper-parasitism of live aphids, which were not previously known from this system.

Publications

• Type: Journal Articles Status: Published Year Published: 2013 Citation: Acebes, A.L. & Messing, R.H. 2013. Host range of a newly introduced parasitoid, Binodoxys communis (Gahan) among common aphid species in Hawaii. BioControl 58: 635-644.

Progress 10/01/11 to 09/30/12

Outputs
OUTPUTS: We conducted experiments to evaluate a newly introduced aphid parasitoid in Hawaii, Binodoxys communis (Gahan), in comparison with a previously introduced aphid parasitoid, Aphidius colemani (Viereck), for susceptibility to attack by extant hyperparasitoids under laboratory conditions. This study was initiated to help explain the low abundance of B. communis in the field in contrast to A. colemani, possibly as a result of apparent competition mediated by the hyperparasitoid Syrphophagus aphidovorus (Mayr). Mummies of the two primary parasitoid species were exposed to adult female S. aphidovorus under both choice and no-choice conditions. Results were disseminated via graduate student presentations at the CTAHR Student Research Symposium and the Entomological Society of America annual meeting, and through discussions with colleagues at the International Congress of Entomology in Korea. PARTICIPANTS: Ms. Angelita Acebes, former graduate student at the University of Hawaii, currently graduate student at Virginia Tech university. Through experience working on this project Ms. Acebes was successful in obtaining her Master's degree; she won several prizes for the presentation of her research results at conferences. Taro farmers Clayton Ueno (Hanapepe) and Wayne Tanji (Hanalei) allowed us to use their farms, and interacted with us on a weekly basis during the research to understand aphid biology and dynamics. TARGET AUDIENCES: Target audiences include all farmers in Hawaii that have exotic invasive aphids attacking their crops. This includes almost all agricultural commodities grown in the state. Additional target audiences include other researchers and Extension agents that interact with farmers and that study aphid pest management and biological control. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Contrary to expectations, we found that B. communis was susceptible to S. aphidovorus attack, but A. colemani was a more suitable host, as shown by higher rates of hyperparasitism when both parasitoid species were exposed simultaneously, and a more female-biased sex ratio of hyperparasitoids emerging from A. colemani mummies. The higher suitability of Aphidius colemani for hyperparasitoid development is likely influenced by its larger size, implying more resources for the hyperparasitoids. No evidence of apparent competition (in terms of the hyperparasitoid's host finding ability or host suitability) was found to be comparatively more unfavorable towards B. communis. This may have positive implications for B. communis establishment and efficacy in the long run.

Publications

• Messing, R.H., Pike, K.S., and Foottit, R.G. 2012. Invasive Aphids in Hawaii. Honolulu: College of Tropical Agriculture and Human Resources, University of Hawaii, 261 pp.