Signatures of genetic bottleneck and differentiation after the introduction of an exotic parasitoid for classical biological control
- 336 Downloads
As biological invasions, intentional introductions often result in a loss of genetic diversity in the new founder populations. In classical biological control programs, natural enemies introduced into novel environments are likely to suffer from population bottlenecks. Unlike invasive populations, individuals for biological control are typically kept in quarantine during several generations before being released in the field. This procedure reduces further the effective population size of the introduced populations, which thus increases the effects of inbreeding and genetic drift, resulting in a greater loss of genetic diversity. This study addresses the genetic consequences of the introduction of the parasitoid wasp Aphidius ervi, a successful biocontrol agent of important aphid target-pests in Chile. This was assessed by examining the genetic diversity and differentiation at nuclear and mitochondrial genetic markers in terms of (1) the magnitude of the genetic diversity loss after 38 years of the introduction of A. ervi, (2) the current level of genetic differentiation between Chilean introduced populations and putative native populations from France, and (3) the genetic relationships and magnitude of the genetic diversity loss between introduced populations of A. ervi in Chile compared to those introduced in North America. The results provide evidence that parasitoid populations suffered the effects of a moderate genetic bottleneck during the introduction, showing further a strong geographical genetic differentiation between populations in the natal and novel environments. In addition mtDNA sequences analysis showed evidence of a single main event of introduction in Chile, unlike the North American situation, where there is evidence for multiple introductions. The significance of the loss of genetic diversity during introductions related to the success of parasitoids as biocontrol agents in classical biological control programs is discussed.
KeywordsGenetic bottleneck Classic biological control Biological invasions Aphid parasitoids Aphidius ervi
The authors thank Cinthya Villegas, Marcos Dominguez and Sebastian Ortiz for their valuable support in laboratory and fieldwork. Thanks to Bernard Chaubet for his help on the species identification and sex determination of the parasitoids, and to Lucie Mieuzet for her help on the experimental part. The authors thank Heidi Connahs as well for the English corrections. This work was funded by FONDECYT 1110341 Grant to BL. FZP also thanks to CONICYT for a PhD fellowship, DID-UACh for a Ph.D. thesis Grant, and MECESUP AUS 0703 Grant to UACh for funding national and international internships.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Beebee TJC, Rowe G (2008) An introduction to molecular ecology. Oxford University Press, OxfordGoogle Scholar
- Belkhir K, Borsa P, Chikhi L et al (1996) GENETIX 4.05, logiciel sous Windows TM pour la génétique des populations. Laboratoire génome, populations, interactions, CNRS UMR 5000:1996–2004Google Scholar
- Drummond A, Ashton B, Buxton S et al (2011) Geneious, version 5. 4. Geneious, AucklandGoogle Scholar
- Gerding MP, Zuñiga ES, Quiroz CE, Norambuena HM, Vargas RM (1989) Abundancia relativa de los parasitoides de Sitobion avenae (F) y Metopolophium dirhodum (WLK) (Homoptera:Aphididae) en diferentes áreas geográficas de Chile. Agricultura técnica (Chile) 49:104–114Google Scholar
- Grevstad F, Coombs E, McEvoy P et al (2013) Revisiting release strategies in biological control of weeds: are we using enough releases? 13th International symposium on the biological control of weeds, Hawaii, USA. US Forest Service Forest Health Technology Enterprise TeamGoogle Scholar
- Hufbauer RA (2001) Pea aphid-parasitoid interactions: have parasitoids adapted to differential resistance? Ecology 82:717–725Google Scholar
- Nei M, Maruyama T, Chakraborty R (1975) The bottleneck effect and genetic variability of populations. Evolution 29:1–10Google Scholar
- Piry S, Luikart G, Cornuet J-M (1999) BOTTLENECK: a program for detecting recent effective population size reductions from allele data frequencies. Montpellier, FranceGoogle Scholar
- R Core Team (2012) R: a language and environment for statistical computing. R Foundation for Statistical Computing, ViennaGoogle Scholar
- Raymond M, Rousset F (1995) An exact test for population differentiation. Evolution 49:1280–1283Google Scholar
- Roderick G, Navajas M (2008) The primacy of evolution in biological control. In: Proceedings of the XII international symposium on biological control of weeds: La Grande Motte, France, 22–27 April 2007. CABI, pp 403–409Google Scholar
- Rojas S (2005) Control biológico de plagas en Chile. Historia y avances. Colección libros INIA N°12. 123p. Instituto de Investigaciones Agropecuarias (INIA), Centro Regional de Investigación La Cruz, La Cruz, ChileGoogle Scholar
- Zuñiga SE, Van den Bosch R, Drea J, Francis G (1986a) Control biológico de los áfidos (Homoptera: Aphididae) de los cereales de Chile. II. Obtención, introducción y cuarentena de depredadores y parasitoides. Agricultura Técnica (Chile) 46:479–487Google Scholar
- Zuñiga SE, Van den Bosch R, Drea JJ et al (1986b) [The biological control project against the cereal aphids (Hom., Aphididae) in Chile. 2: Exploration, importation and quarantine of predator and parasitoid species]. Agricultura Tecnica (Chile)Google Scholar