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United States Department of Agriculture

Agricultural Research Service

Research Project: GENETICS OF HOST SPECIFICITY AND CLIMATIC ADAPTATION IN BIOLOGICAL CONTROL AGENTS INTRODUCED FOR CONTROL OF ARTHROPOD PESTS AND WEEDS

Location: Beneficial Insects Introduction Research

2006 Annual Report


1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? Why does it matter?
Unintentional introductions of exotic species that become pests is an increasing problem for agriculture, human health, and the environment. Increasing cost of pesticide development, rapid evolution of target resistance to pesticides, pest resurgence after destruction of natural enemies by pesticides, and public concern about health and environmental impact of pesticides demand alternatives for pest management. For introduced pests, biological control by introduction of exotic natural enemies is an important way of reducing pest abundance and thus impact. Although biological control introductions have been practiced for over 100 years, not enough is known about the factors that determine success. Furthermore, controversy has arisen concerning the risk of impact on non-target species. This project will use past and new introductions to test the effects of host specificity and climatic adaptation on natural enemy establishment, efficacy, and impact on non target species.

Host specificity is crucial for biological control of insect pests and weeds. The likelihood that a host specific insect will evolve to attack a novel host species depends on how many genes are involved, how these genes interact, how much change in each gene is needed to cause a shift in host use. The first objective is to determine the genetic basis for host specificity in certain parasitoids and herbivores. We will test the hypothesis that host use is determined by many genes of small effect interacting epistatically, rendering saltational changes in host range unlikely. Using crosses, quantitative trait loci (QTL) mapping and differences in gene expression, we will determine the genetic basis for a host shift in the specialist herbivore, HELIOTHIS SUBFLEXA, and for differences in host specificity between species in the APHELINUS VARIPES complex. We will confirm gene function by silencing with RNA interference. Two important arguments have been made against introductions of natural enemies for biological control. First, introduced natural enemies may attack native non-target species. Second, native natural enemies may switch to attack invading pests and control them without the need for introductions. We will analyze of host ranges in parasitoid species in the APHELINUS VARIPES complex introduced to control the Russian wheat aphid, DIURAPHIS NOXIA, and in endemic APHELINUS spp. which may have evolved to attack D. NOXIA since its accidental introduction.

Climate matching is frequently used to decide where to collect biocontrol agents for introduction. However, three hypotheses can explain climatic adaptation: (1) populations in different regions are adapted to local climates, (2) single populations have the full range of genetic variation in traits affecting climatic adaptation, (3) physiological plasticity is sufficient for local adaptation. These hypotheses have very different implications for collection strategies. The second objective is to test these hypotheses using the APHELINUS VARIPES complex.

In the third objective, we will use the knowledge and methods developed under objectives 1 and 2 to screen candidates proposed for introduction to control DIURAPHIS NOXIA and APHIS GLYCINES, introduce the most promising candidates, evaluate their impact on target and non-target species, and determine whether the screening was useful in improving the success and safety of biocontrol introductions. The results of this research will increase establishment and efficacy of introduced natural enemies and decrease damage by pests, while increasing the safety of biocontrol introductions. How serious is the problem? Why does it matter?

This research will increase establishment and efficacy of introduced natural enemies and thus decrease damage by pests, while increasing the safety of biocontrol introductions. This will benefit U.S. farmers by reducing their losses to pests and costs for production, and it will benefit the general public by decreasing costs of food and fiber and reducing adverse impacts on human health and the environment. Target pests for this project were chosen because of their high impact on U.S. agriculture. DIURAPHIS NOXIA, the Russian wheat aphid, is a major pest of wheat and barley, causing over $1 billion damage since 1987. APHIS GLYCINES, the soybean aphid, infested 42 million acres of soybean in the US, causing $1 billion in damage and control costs in 2003 alone. Weeds in the US are estimated to cost American agriculture $13 billion annually in control expenditures and yield losses (ARS National Program Plan). Environmental impacts of weeds are difficult to quantify, but the President’s Executive Order on Invasive Species (3 February 1999) states that they are a major threat to our parks, forests, rivers, and shores. Two categories of customers will benefit from results of this project. The first is users of published research, who are scientists at universities, state departments of agriculture and natural resources, federal agencies, and conservation organizations, and decision makers at state departments of agriculture and natural resources, federal agencies, conservation organizations. The second includes farmers growing crops attacked by target pests, who benefit from reduced production costs and reduced exposure to toxic substances, and the general public, who benefit from reduced prices, reduced health risks from pollution, reduced impact on non target species. National Program (NP) to which the project is aligned This research addresses components III Plant, pest, and natural enemy interactions and ecology, V Pest control technologies, and IX Biological control of weeds of ARS National Program 304 on Crop Protection and Quarantine. This project involves cooperation with the Institute of Plant Protection (Chinese Academy of Agricultural Sciences), University of Minnesota and Purdue University for biological control of soybean aphid, with Texas A&M University for morphometric analysis of sibling species of aphid parasitoids, with University of California Riverside for molecular systematics of sibling species of aphid parasitoids, and with North Carolina State University and University of Maryland for genetics of host specificity in noctuid moths.


2.List by year the currently approved milestones (indicators of research progress)
FY 2006 1.1.1 To determine the genetics of host specificity in APHELINUS spp., assay host use by hybrid progeny from interspecific crosses involving species that differ in host use. 1.3.4 To determine the genetics of host specificity in HELIOTHIS spp., test bioassay for oviposition on a novel host plant.

FY 2007 1.3.1 To determine the genetics of host specificity in HELIOTHIS spp., analyze molecular markers for mapping quantitative trait loci affecting feeding on cotton by hybrid larvae from interspecific cross between H. SUBFLEXA and H. VIRESCENS.

FY 2008 1.1.2 To determine the genetics of host specificity in APHELINUS spp., analyze molecular markers for mapping quantitative trait loci affecting host specificity. 1.2.1 To determine whether host specificity of APHELINUS spp. has evolved post-introduction, collect APHELINUS VARIPES populations on Russian wheat aphid, other aphids on small grains, and noncrop host plants. 1.3.2 To determine the genetics of host specificity in HELIOTHIS spp., probe and analyze bacterial artificial chromosome library to identify genes affecting larval feeding on a novel host plant. 2.1 To test climate matching versus adaptation, collect APHELINUS VARIPES populations on Russian wheat aphid, other aphids on small grains, and non-crop host plants.

FY 2009 1.1.3 To determine the genetics of host specificity in APHELINUS spp., probe and analyze bacterial artificial chromosome library to identify genes underlying host specificity. 1.2.2 To determine whether host specificity of APHELINUS spp. has evolved post introduction, compare of DNA sequences and reproductive compatibility to find which APHELINUS VARIPES populations released against Russian wheat aphid have established. 1.3.3 To determine the genetics of host specificity in HELIOTHIS spp., analyze differences in gene expression between hybrid larvae that do versus do not feed on a novel host plant. 2.2 To test climate matching versus adaptation, determine source of introduced APHELINUS VARIPES populations. 3.3.2 To evaluate impacts of parasitoids introduced against DIURAPHIS NOXIA, collect parasitoids on target and non-target aphids.

FY 2010 1.1.4 To determine the genetics of host specificity in APHELINUS spp., analyze differences in gene expression between hybrid wasps that do versus do not parasitize a novel host aphid. 1.1.5 To determine the genetics of host specificity in APHELINUS spp., develop molecular phylogeny of genes affecting feeding on a novel host. 1.2.3 To determine whether host specificity of APHELINUS spp. has evolved post introduction, assay host use of established APHELINUS VARIPES populations for which preintroduction data are available. 1.3.5 To determine the genetics of host specificity in HELIOTHIS spp., develop molecular phylogeny of genes affecting feeding on a novel host plant. 2.3 To test climate matching versus adaptation, assay differences in climatic tolerances between source and introduced APHELINUS VARIPES populations; for those that differ, cross and assay climatic tolerance of hybrid progeny. 2.4 To test climate matching versus adaptation, for source and introduced APHELINUS VARIPES populations that differ in climatic tolerances, measure differences in expression of heat shock and other proteins. 3.1.1 Screen host specificity of candidates for introduction against APHIS GLYCINES. 3.1.2 For species of parasitoids of APHIS GLYCINES with sufficiently narrow host ranges, measure climatic tolerances. 3.1.3 For species of parasitoids of APHIS GLYCINES with sufficiently narrow host ranges, write and submit assessments of potential for environmental impact of introductions.


4a.List the single most significant research accomplishment during FY 2006.
GENETIC ARCHITECTURE OF PARASITOID HOST SPECIFICITY Host specificity is crucial for safe biological control introductions against insect pests and weeds. The likelihood that a host specific insect will evolve to attack a novel host species depends on the genetic architecture of host use, about which very little is known. Using reproductive compatibility between allopatric species in the APHELINUS VARIPES complex, we introgressed genes for parasitizing Russian wheat aphid, DIURAPHIS NOXIA, from one parasitoid species to another in laboratory crosses, and we used these crosses to map quantitative trait loci (QTL) involved in host specificity. Two QTL explained 7 percent of the variation in parasitism of Russian wheat aphid. This is the first analysis of the genetic architecture of differences in host specificity of parasitoid species. This accomplishment relates to Problem Statements A Understanding Complex Interactions and B Population Studies/Ecology under National Program Component III Plant, Pest, and Natural Enemy Interactions and Ecology; and Problem Statement A Traditional Biological Control under National Program Component V Pest Control Technologies.


4b.List other significant research accomplishment(s), if any.
HIGH PARASITISM OF THE RUSSIAN WHEAT APHID The Russian wheat aphid is a major pest of wheat and barley crops in the western states. Parasitoids in the APHELINUS VARIPES complex were released a decade ago to control the Russian wheat aphid. Collections in Colorado, Nebraska, and Wyoming showed that Russian wheat aphid is now heavily parasitized by species in the APHELINUS VARIPES complex. This accomplishment relates to Problem Statement A Traditional Biological Control under National Program Component V Pest Control Technologies.

EVOLUTION OF REPRODUCTIVE INCOMPATIBILITY IN CRYPTIC SPECIES OF PARASITOIDS Phylogenetic analysis using sequences from six genes delineated relationships among lineages of parasitic wasps in the APHELINUS VARIPES species complex from throughout Eurasia and from three pest aphids, oat birdcherry aphid, Russian wheat aphid, and soybean aphid. The periods between lineage divergences varied at least 10 fold, but the data were consistent with a constant and high rate of origination and extinction of lineages. The youngest lineages differed by 0.07 percent in DNA sequence and diverged 48 125K years ago, and the oldest lineages differed by 0.5 0.7 percent in DNA sequence and diverged 205 526K years ago. Geographical and phylogenetic proximity were not related. Distantly related lineages were less likely to crossbreed than closely related ones, but the amount of genetic divergence was not precise predictor of reproductive compatibility. Pre zygotic incompatibility was much more common than post zygotic incompatibility in this complex, and sympatric lineages were less likely to crossbreed than allopatric lineages. These results suggest that genetic introgression may occur between allopatric species put in sympatry by introductions, which would risk evolutionary shifts in host specificity and unforeseen impacts on nontarget species. This accomplishment relates to Problem Statement A Understanding Complex Interactions under National Program Component III Plant, Pest, and Natural Enemy Interactions and Ecology; Problem Statement A Traditional Biological Control under National Program Component V Pest Control Technologies.

COURTSHIP DIFFERENCES IN SIBLING SPECIES OF PARASITOIDS In a collaboration between the Beneficial Insects Introduction Research Unit, the University of California Riverside, and Texas A&M, we found that antennation behavior duration courtship differed among males of cryptic species in APHELINUS-VARIPES complex. These differences are probably involved in species recognition and explain why some species in this complex hybridize and others do not. The results will help evaluation of the risk of interbreeding between introduced biocontrol agents in this complex and native species. This accomplishment relates to Problem Statements A Understanding Complex Interactions under National Program Component III Plant, Pest, and Natural Enemy Interactions and Ecology; and Problem Statement A Traditional Biological Control under National Program Component V Pest Control Technologies.

MORPHOMETRIC DIFFERENCES AMONG CRYPTIC SPECIES OF PARASITOIDS Distinguishing cryptic species of parasitoids is crucial for the safety and efficacy of biological control introductions because these species often have different host ranges and climatic tolerances which will affect their establishment and impact on target and non-target species. We used geometric morphometric methods to study differentiation in antennae, fore wings and thorax for male and female specimens from populations in the APHELINUS VARIPES complex from various geographical regions and host species, representing at least five cryptic species. Multivariate statistical analysis of landmarks and distances between landmarks showed that morphological differentiation between these cryptic species was consistent and significant. This research relates to Problem Statements A Understanding Complex Interactions under National Program Component III Plant, Pest, and Natural Enemy Interactions and Ecology; and Problem Statement A Traditional Biological Control under National Program Component V Pest Control Technologies.


4c.List significant activities that support special target populations.
None.


4d.Progress report.
ANCHORED MARKERS FOR GENETIC ANALYSES Markers for genetic mapping are important tools for analysis of genes involving host specificity, climatic adaptation, and other traits. Such markers are particularly useful if their location and homology can be determined, using published sequences for known genes in HELIOTHIS VIRESCENS, we have developed primers for DNA amplification that produce length differences that can be used for genetic mapping in experimental crosses between this moth species and HELIOTHIS SUBFLEXA. We will use these markers in our analysis of the genetic architecture of host specificity, but these primer sequences and gene locations should prove very useful to the scientific community working on this complex. This research relates to Problem Statement A Understanding Complex Interactions under National Program Component III Plant, Pest, and Natural Enemy Interactions and Ecology; Problem Statement A Traditional Biological Control under National Program Component V Pest Control Technologies; and Problem Statement A Agent Discovery and Selection and Risk Assessment under National Program Component IX Biological Control of Weeds.

1926 22000 017 01T: This report documents research under a Trust agreement between ARS and the USDA National Research Initiative Competitive Grants Program. We found subtle differences in antennation behavior duration courtship by males of species in APHELINUS VARIPES complex, which are probably involved in species recognition and may explain why some species in this complex hybridize and others do not. The results will help evaluation of the risk of interbreeding between introduced biocontrol agents in this complex and native species. Host specificity is crucial for safe biological control introductions against insect pests and weeds. The likelihood that a host specific insect will evolve to attack a novel host species depends on the genetic architecture of host use, about which very little is known. Using reproductive compatibility between allopatric species in the APHELINUS VARIPES complex, we introgressed genes for parasitizing Russian wheat aphid, DIURAPHIS NOXIA, from one parasitoid species to another in laboratory crosses, and we used these crosses to map quantitative trait loci (QTL) involved in host specificity. Two QTL explained 7 percent of the variation in parasitism of Russian wheat aphid, which suggests that this change in host use is likely. This is the first analysis of the genetic architecture of differences in host specificity of parasitoid species. This research relates to Problem Statements A Understanding Complex Interactions and B Population Studies/Ecology under National Program Component III Plant, Pest, and Natural Enemy Interactions and Ecology; and Problem Statement A Traditional Biological Control under National Program Component V Pest Control Technologies.

1926 22000 017 02S and 1926 22000 017 05R: This report documents research conducted under a specific cooperative agreement between ARS and the University of Delaware and under an interagency Reimbursable agreement between ARS and Purdue University. We have evaluated host range of 16 species/populations of biological control agents from China, Japan, and Korea that are candidates for introduction against the soybean aphid, APHIS GLYCINES, a major new pest of soybeans in the U.S. Although most populations of parasitoids differed in host range, 13 had broad host ranges and these have been eliminated from consideration for introduction and their culture in quarantine discontinued. Two populations in the APHELINUS VARIPES complex and a population of BINODOXYS COMMUNIS had narrower host ranges. We are proceeding with research on these three populations because they are the most promising candidates for release against soybean aphid. We measured reproductive compatibility among 5 populations of the APHELINUS VARIPES complex from China, Korea, and Japan and all were reproductively compatible, although they differed in host specificity, demonstrating that host specificity must be measured for each population. This accomplishment relates to Problem Statements A Understanding Complex Interactions under National Program Component III Plant, Pest, and Natural Enemy Interactions and Ecology; and Problem Statement A Traditional Biological Control under National Program Component V Pest Control Technologies.

1926 22000 017 03S: This report documents research under a specific cooperative agreement between ARS and Texas A&M University which began in February 2003. We used geometric morphometric methods to study differentiation in antennae, fore wings and thorax for male and female specimens from populations in the APHELINUS VARIPES complex from various geographical regions and host species, representing at least five cryptic species. We measured landmark locations of antennal segments, forewings, and thorax 462 specimens using a digital camera and Optimas image analysis software. Multivariate statistical analysis of distances between landmark location using principal component and canonical variates analysis showed that morphological differentiation between these cryptic species was consistent and significant. However, characterization and visualization of these differences is difficult using distance based methods. Thus, we used geometric morphometrics, which can be used to study variation in size and shape of biological forms by statistical analysis of the locations of landmark points only, without reference to distances calculated between landmarks. MANOVA showed a significant sex effect so females and males were separately analyzed for each body region. Populations differed for all body regions in both males and females. Both sexes showed significant host effects on morphology for all of the body regions except male pedicel. Discriminant analysis performed well for both male and female thorax, but poorly for wings and antennal regions. Discriminant analysis based on wing and antennal distances was much more successful. The third funicular segments of males have two distinct shapes and those of females have three distinct shapes. In forewings, the most significant shape differences were in the delta area. Females and males had similar shape changes. Shape differences in the thorax were found at the anterior and posterior margins, as well as in the position of anterior and posterior scutellar setae. Females and males had similar shape deformations compared to the consensus form. This research relates to Problem Statements A Understanding Complex Interactions under National Program Component III Plant, Pest, and Natural Enemy Interactions and Ecology; and Problem Statement A Traditional Biological Control under National Program Component V Pest Control Technologies.

1926 22000 017 04S: This report documents research under a Specific Cooperative agreement between ARS and the University of California Riverside which began in February 2003. Phylogenetic analysis using sequences from six genes delineated relationships among lineages of parasitic wasps in the APHELINUS VARIPES species complex from throughout Eurasia and from three aphid hosts. Four clades were identified: (1) a lineage from RHOPALOPSIPHUM PADI in Georgia, (2) a lineage from DIURAPHIS NOXIA in France, (3) lineages from D. NOXIA in Georgia and from R. PADI in France and Israel, and (4) lineages from APHIS GLYCINES in China, Korea and Japan. The periods between lineage divergences varied at least 10 fold. The data were consistent with a constant and high rate of origination and extinction of lineages. Geographical and phylogenetic proximity were not related. Distantly related lineages were less likely to crossbreed than closely related ones. Sympatric lineages were less likely to crossbreed than allopatric lineages. The youngest divergence between incompatible lineages was between those from D. NOXIA in Georgia and R. PADI in France, which differed by 0.07 percent in DNA sequence and diverged 48 125K years ago. The oldest divergences between incompatible lineages were between the lineage from R. PADI in Georgia and other lineages, which differed by 0.5 0.7 percent in DNA sequence plus 9 10 indel events, and diverged from them 205 526K years ago. Pre zygotic incompatibility was much more common than post zygotic incompatibility in this complex. The amount of genetic divergence was not a good predictor of reproductive compatibility for closely related lineages. This research relates to Problem Statement A Understanding Complex Interactions under National Program Component III Plant, Pest, and Natural Enemy Interactions and Ecology; Problem Statement A Traditional Biological Control under National Program Component V Pest Control Technologies.


5.Describe the major accomplishments to date and their predicted or actual impact.
GENETIC ARCHITECTURE OF PARASITOID HOST SPECIFICITY Host specificity is crucial for safe biological control introductions against insect pests and weeds. The likelihood that a host specific insect will evolve to attack a novel host species depends on the genetic architecture of host use, about which very little is known. Using reproductive compatibility between allopatric species in the APHELINUS VARIPES complex, we introgressed genes for parasitizing Russian wheat aphid, DIURAPHIS NOXIA, from one parasitoid species to another in laboratory crosses, and we used these crosses to map quantitative trait loci (QTL) involved in host specificity. Two QTL explained 7 percent of the variation in parasitism of Russian wheat aphid. This is the first analysis of the genetic architecture of differences in host specificity of parasitoid species. This accomplishment relates to Problem Statements A Understanding Complex Interactions and B Population Studies/Ecology under National Program Component III Plant, Pest, and Natural Enemy Interactions and Ecology; and Problem Statement A Traditional Biological Control under National Program Component V Pest Control Technologies.

HIGH PARASITISM OF THE RUSSIAN WHEAT APHID The Russian wheat aphid is a major pest of wheat and barley crops in the western states. Parasitoids in the APHELINUS VARIPES complex were released a decade ago to control the Russian wheat aphid. Collections in Colorado, Nebraska, and Wyoming showed that Russian wheat aphid is now heavily parasitized by species in the APHELINUS VARIPES complex. This accomplishment relates to Problem Statement A Traditional Biological Control under National Program Component V Pest Control Technologies.

EVOLUTION OF REPRODUCTIVE INCOMPATIBILITY IN CRYPTIC SPECIES OF PARASITOIDS Phylogenetic analysis using sequences from six genes delineated relationships among lineages of parasitic wasps in the APHELINUS VARIPES species complex from throughout Eurasia and from three pest aphids, oat birdcherry aphid, Russian wheat aphid, and soybean aphid. The periods between lineage divergences varied at least 10 fold, but the data were consistent with a constant and high rate of origination and extinction of lineages. The youngest lineages differed by 0.07 percent in DNA sequence and diverged 48 125K years ago, and the oldest lineages differed by 0.5 0.7 percent in DNA sequence and diverged 205 526K years ago. Geographical and phylogenetic proximity were not related. Distantly related lineages were less likely to crossbreed than closely related ones, but the amount of genetic divergence was not precise predictor of reproductive compatibility. Pre zygotic incompatibility was much more common than post zygotic incompatibility in this complex, and sympatric lineages were less likely to crossbreed than allopatric lineages. These results suggest that genetic introgression may occur between allopatric species put in sympatry by introductions, which would risk evolutionary shifts in host specificity and unforeseen impacts on non target species. This accomplishment relates to Problem Statement A Understanding Complex Interactions under National Program Component III Plant, Pest, and Natural Enemy Interactions and Ecology; Problem Statement A Traditional Biological Control under National Program Component V Pest Control Technologies.

COURTSHIP DIFFERENCES IN SIBLING SPECIES OF PARASITOIDS In a collaboration between the Beneficial Insects Introduction Research Unit, the University of California Riverside, and Texas A&M, we found that antennation behavior duration courtship differed among males of cryptic species in APHELINUS VARIPES complex. These differences are probably involved in species recognition and explain why some species in this complex hybridize and others do not. The results will help evaluation of the risk of interbreeding between introduced biocontrol agents in this complex and native species. This accomplishment relates to Problem Statements A Understanding Complex Interactions under National Program Component III Plant, Pest, and Natural Enemy Interactions and Ecology; and Problem Statement A Traditional Biological Control under National Program Component V Pest Control Technologies.

MORPHOMETRIC DIFFERENCES AMONG CRYPTIC SPECIES OF PARASITOIDS Distinguishing cryptic species of parasitoids is crucial for the safety and efficacy of biological control introductions because these species often have different host ranges and climatic tolerances which will affect their establishment and impact on target and non target species. We used geometric morphometric methods to study differentiation in antennae, fore wings and thorax for male and female specimens from populations in the APHELINUS VARIPES complex from various geographical regions and host species, representing at least five cryptic species. Multivariate statistical analysis of landmarks and distances between landmarks showed that morphological differentiation between these cryptic species was consistent and significant. This research relates to Problem Statements A Understanding Complex Interactions under National Program Component III Plant, Pest, and Natural Enemy Interactions and Ecology; and Problem Statement A Traditional Biological Control under National Program Component V Pest Control Technologies.

INTRAGUILD PREDATION ON SOYBEAN APHID PARASITOIDS In a collaboration between the Beneficial Insects Introduction Research Unit, the University of Minnesota, and the Institute of Plant Protection (Chinese Academy of Agricultural Sciences), we tested whether predators differentially preyed on aphids parasitized by braconid versus aphelinid parasitoids. Aphids parasitized by aphelinids suffered a predation rate double that of those parasitized by braconids, but the difference can be accounted for by the longer time period that aphelinid parasitized aphids are vulnerable to parasitism. This result suggests that aphelinids will face greater biotic resistance to colonization in the US. This accomplishment relates to Problem Statements A Understanding Complex Interactions under National Program Component III Plant, Pest, and Natural Enemy Interactions and Ecology; and Problem Statement A Traditional Biological Control under National Program Component V Pest Control Technologies.

HOST RANGES OF PARASITOIDS FOR BIOLOGICAL CONTROL OF SOYBEAN APHID We have evaluated host range of 16 species/populations of biological control agents from China, Japan, and Korea that are candidates for introduction against the soybean aphid, APHIS GLYCINES, a major new pest of soybeans in the U.S. Although most populations of parasitoids differed in host range, 13 had broad host ranges, these have been eliminated from consideration for introduction and their culture in quarantine discontinued. Two populations in the APHELINUS VARIPES complex and a population of BINODOXYS COMMUNIS had narrower host ranges. We are proceeding with research on these three populations because they are the most promising candidates for release against soybean aphid. We measured reproductive compatibility among 5 populations of the APHELINUS VARIPES complex from China, Korea, and Japan and all were reproductively compatible, although they differed in host specificity, demonstrating that host specificity must be measured for each population. This accomplishment relates to Problem Statements A Understanding Complex Interactions under National Program Component III Plant, Pest, and Natural Enemy Interactions and Ecology; and Problem Statement A Traditional Biological Control under National Program Component V Pest Control Technologies.


6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products?
None.


7.List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below).
None.


Review Publications
Bilu, E., Hopper, K.R., Coll, M. 2006. Host choice by aphidius colemani: effects of plants, plant-aphid combinations and the presence of intraguild predators. Ecological Entomology. 31:331-336.

Hopper, K.R., Farias, A.M., Woolley, J.B., Heraty, J.M., Britch, S.C. 2005. Genetics: relation of local populations to the whole "species" - implications for host range tests. Second International Symposium on Biological Control of Arthropods. p 665-671.

Hopper, K.R., Britch, S.C., Wajnberg, E. 2006. Risks of interbreeding between species used in biological control and native species and methods for evaluating its occurrence and impact. Pp. 78-97 D. Babendreier, F. Bigler and U. Kuhlmann, eds. Environmental Impact of Invertebrates for Biological Control of Arthropods: Methods and Risk Assessment. CABI Biosciences, London.

Last Modified: 9/29/2014
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