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Diabrotica v. virgifera wing shape variation reveals multiple populations across the European expansion front
Darija Lemic1, Katarina M Mikac2, Hugo A Benitez 3,
Renata Bažok1, Marina Buketa 1
1University of Zagreb, Department for Agricultural Zoology, Croatia2Institute for Conservation Biology & Law, University of Wollongong, Australia
3 Faculty of Life Sciences, University of Manchester, United Kingdom
International Conference on the German Diabrotica Research Program: Berlin 14 - 16 November 2012
• To enhance management & control understanding the temporal & spatial genetic structure (FST), number of genetic clusters (K) & pattern of gene flow (Nm) is required
• Despite multiple genetic studies revealed no genetic structure among population in the US or Europe
• A preliminary study of the genetic structure of 6 populations in Croatia also showed no genetic structureusing ‘core set’ msat markers
• A need for alternative markers that detect inter-population variation are required
WCR in Europe & Croatia
Kim & Sappington (2005) Molecular Ecology Resources; Ciosi et al. (2008) Molecular Ecology; Kim et al. (2008) Environmental Entomology
• GM techniques provide information on [wing] shape through the relative position of homologous landmarks
• Wing size & shape has been used to estimate the population structure of insect vectors of Trypanosomiasis
Geometric morphometrics (GM)
Camara et al. (2006) Journal of Medical Entomology; Bouyer et al. (2007) Journal of Medical Entomology; Dumonteil et al. (2007) American Journal of Tropical Medicine & Hygiene; Gurgel-Gonçalves et al. (2008) Acta Tropica
GM vs Msats
• GM estimates of population structure supported msats estimates for Triatoma dimidiata
& Glossina palpalis gambiensis
• Surprisingly, wing shape analysis of G. p. gambiensis found population structure at a greater resolution than the msats
Camara et al. (2006); Dumonteil et al. (2007) American Journal of Tropical Medicine & Hygiene
1. Use the ‘core set’ msats to estimate the historical & contemporary (1996 & 2009) population genetic structure of WCR inCroatia
2. Explore the use of wing shape (geometric morphometrics (GM)) to estimate the population structure of WCR in Croatia
Aim
Materials & Methods
Study location/sites
LOCATIONn
1996 2009 2011
1. BOŠNJACI 30 30 30
2. MIKANOVCI 30 30 30
3. VRBANJA 30 30 30
4. OTOK 30 30 30
5. NUŠTAR 30 30 30
GeneticAnalyses
GM Analyses
Genetic MethodsDNA extraction
Kim & Sappington (2005) Molecular Ecology Notes; Kim et al. (2008) Environmental Entomology; Miller et al. (2007) Journal of Applied Entomology; Raymond & Rousset (1995a,b) Evolution, Journal of Heredity; Rosenberg (2004) Molecular Ecology Notes; Weir & Cockerham (1984) Evolution; Pritchard et al. (2000) Genetics
Populations• 1996• 2009Total 201
individuals
Msats (core set)
Multiplex PCR
DVV-D2
DVV-T2
Dba 05
Multiplex PCR
DVV-D4
DVV-D8
Dba 07
Genotyped using ABI 3130XL
Genetic Analyser
Statistical analysis
HWEGenetic Clusters/
Genetic StructureNumber of Alleles
Identification
of source
GM Methods
LOCATIONn
2011
1. BOŠNJACI 30R, 30L
2. MIKANOVCI 30R, 30L
3. VRBANJA 30R, 30L
4. OTOK 30R, 30L
5. NUŠTAR 30R, 30L
Total: 150 Left & 150 Right wings
Materials & Methods
Statistics
• Landmark digitizing – tpsDIG v2.16 (Rohlf, 2008)
• MorphoJ v1.04a (Klingenberg, 2011) Asymmetry and sexual dimorphism analyses GM data analyses Principal component analyses Canonical variate analyses Mahalanobis distances Isolation by distance
Bošnjaci 1996
Mikanovci1996
Vrbanja 1996
Otok1996
Nuštar1996
Bošnjaci 2009
Mikanovci2009
Vrbanja 2009
Otok 2009
Nuštar 2009
K96=1 K09=1Microsatellites showed little genetic
differentiation across populations & time
(1996 & 2009)
FST:96=0.027 FST:09=0.009
Results & DiscussionGenetic Analyses
Results & DiscussionGM Wing Shape
Bošnjaci
Mikanovci
Vrbanja
Otok
Nuštar
Results & DiscussionGM– Mahalanobis distances
Bošnjaci Mikanovci Vrbanja Otok Nuštar
Bošnjaci 42 21 17 38
Mikanovci 2, 61 79 42 31
Vrbanja 2, 68 2, 34 25 61
Otok 4, 10 4, 49 3, 96 29
Nuštar 2, 06 2, 26 2, 40 4, 36
4.228
2.862
2.770
2.925
2.845
Bošnjaci
Mikanovci
Vrbanja
Otok
Nuštar
IBD (r = 0.4, P<0.05)
Significant pairwise differences in 2011 were
noted between all sampled sites
Conclusion
Perhaps microsatellites aren’t able to detect fine scale variation associated with rapidly mobile invasive species,
therefore the use of others genetic markers or phenotypic markers must be explored
This study found that a significant amount of variation in wing morphology (shape & size) exists in WCR across their
invaded range in Croatia
Use of wing morphology can provide valuableaddition information on population structurewhen used with msats especially acrosssuspected genetically homogenous geographiclandscapes
Implications
Acknowledgements
• Dr Mark Schutze, QUT, Australia
• Ms Stephanie Ivkosic, UOW, Australia
• Mr Joshua Douglas, UOW, Australia