1. BIOREpository

Host specialization of aphid parasitoids

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Primary Data

Project title
Host specialization of aphid parasitoids
Code
128174
Project Coordinator
Participant Organization(s)
 
Project URL
 
Status
Completed
Start date
01-01-2010
Expected Completion
31-12-2012
 
Co-Investigator(s)

Description

Abstract
Parasitoids of insects represent a substantial fraction of arthropod biodiversity. Their enormous diversity may reflect the fact that development inside a living host requires many particular adaptations, which in turn may lead to strong selection for host specialization. Indeed, despite ample variation in parasitoid host ranges, the number of hosts attacked by parasitoids is often a very restricted subset of apparently similar hosts. Furthermore, the advent of highly resolving molecular markers has shown that some cases of seemingly generalist parasitoids in fact represent species groups of morphologically cryptic, host-specialized taxa. Because many parasitoids are important natural enemies of pest insects, the resolution of such cases is of great agricultural importance.This is particularly true for aphid parasitoids of the subfamily Aphidiinae (Hymenoptera: Braconidae), which are very valuable for biocontrol of pest aphids in green houses as well as open crop fields. Despite their economical importance, knowledge about host specialization within morphologically distinguishable taxa is surprisingly scarce. We, a team of Swiss and Serbian scientists aided by an expert from the Czech Republic, propose to address this issue in three different species or species groups. All of these are natural enemies of pest aphids, and each group offers a particular opportunity to yield insights into general questions on the evolution of host specialization in parasitoids:Sub-project A looks at host specialization in three closely aphid parasitoids of the genus Lysiphlebus: L. fabarum, L. cardui and L. confusus. In each of these species, sexual and asexual populations can be found, which is highly unusual among aphid parasitoids. It is currently unclear how this variation in the reproductive mode affects the evolution of host specialization, but preliminary data suggest some differences in host associations among sexual and asexual populations. It is also unclear whether asexual populations, which exhibit comparatively broad host ranges, may in fact consist of many divergent asexual lineages with more narrow host ranges. We will address these questions using a combination of comprehensive field sampling, genetic analyses with nuclear (microsatellites) and mitochondrial (COI) genetic markers, and host transplant experiments.Sub-project B is concerned with Lysiphlebus testaceipes, a North American parasitoid that was introduced into the Mediterranean as a biocontrol agent of citrus aphids. Since its introduction in the 1970s, L. testaceipes has spread rapidly and acquired many new hosts from the native Mediterranean aphid fauna. It is unclear whether this reflects extreme generalism or whether L. testaceipes consists of multiple, host-associated lineages. Using microsatellites and mitochondrial DNA sequences as well as modern morphometric approaches, we will test for differentiation among wasps associated with different hosts. If we detect a genetic signature of host specialization, it will be interesting to assess whether specialized lineages were already introduced from America, or whether L. testaceipes evolved host specialization in situ during the short period since its introduction. This will be possible by also studying samples from its native range.Sub-project C addresses host specialization in the morphologically cryptic Praon dorsale-yomenae species complex. This group is suspected to be paraphyletic, consisting of several hidden taxa with specific host adaptations and distributions. However, a systematic approach to resolve this issue has so far been lacking. Our project will attempt to delineate species boundaries and elucidate patterns of host specialization in this complex.Apart from its scientific interest, this project will provide an opportunity for young Serbian scientist to become acquainted with modern genetic approaches in population biology, and for young Swiss scientists to benefit from the taxonomic expertise of their Serbian colleagues. By establishing this internation collaboration as well as supporting and training three Serbian PhD students, this project will make a significant contribution to building up and improving the research capacity of the Serbian partner team in Belgrade. Last but not least, we hope that our work will provide useful information for successful and efficient biological control of pest aphids.
 
Keyword(s)
host specialization, parasitoid, biological control, aphids, evolution, cryptic species, molecular markers, biocontrol, Lysiphlebus, microsatellites, mtDNA, morphometrics, parasitoids

Publications
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Results 1-1 of 1 (Search time: 0.002 seconds).

Issue DateTitleAuthor(s)Rank
11-Jan-2015Genetic and morphological variation in sexual and asexual parasitoids of the genus Lysiphlebus - An apparent link between wing shape and reproductive modePetrović, Anđeljko ; Mitrović, Milana; Ivanović, Ana ; Žikić, Vladimir; Kavallieratos, Nickolas; Starý, Petr; Bogdanović, Ana Mitrovski; Tomanović, Željko ; Vorburger, ChristophM22