These expansions are largely due to tandem duplication, a possible adaptation mechanism enabling polyphagy.
Anaïs Gouin, Anthony Bretaudeau, Kiwoong Nam, Sylvie Gimenez, Jean-Marc Aury, BernardDuvic, Frédérique Hilliou, Nicolas Durand, Nicolas Montagné, Isabelle Darboux, SuyogKuwar, Thomas Chertemps, David Siaussat, Anne Bretschneider, Yves Moné, Seung-JoonAhn, Sabine Hänniger, Anne-Sophie Gosselin Grenet, David Neunemann, Florian Maumus,Isabelle Luyten, Karine Labadie, Wei Xu, Fotini Koutroumpa, Jean-Michel Escoubas,Angel Llopis, Martine Maïbèche-Coisne, Fanny Salasc, Archana Tomar, Alisha R. Anderson,Sher Afzal Khan, Pascaline Dumas, Marion Orsucci, Julie Guy, Caroline Belser, AdrianaAlberti, Benjamin Noel, Arnaud Couloux, Jonathan Mercier, Sabine Nidelet, Emeric Dubois,Nai-Yong Liu, Isabelle Boulogne, Olivier Mirabeau, Gaelle Le Goff, Karl Gordon, JohnOakeshott, Fernando L. Consoli, Anne-Nathalie Volkoff, Howard W. Fescemyer, JamesH. Marden, Dawn S. Luthe, Salvador Herrero, David G. Heckel, Patrick Wincker, GaelJ. Kergoat, Joelle Amselem, Hadi Quesneville, Astrid T. Groot, Emmanuelle Jacquin-Joly,Nicolas Nègre, Claire Lemaitre, Fabrice Legeai, Emmanuelle d'Alençon, Philippe Fournier 2017, 'Two genomes of highly polyphagous lepidopteran pests (Spodoptera frugiperda, Noctuidae)with different host-plant ranges', Scientific Reportshttp://link.springer.com/article/10.1038/s41598-017-10461-4. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
As yet however we have little understanding of their origins or the genomic basis of their extreme polyphagy.
David H. Lunt, Sujai Kumar, Georgios Koutsovoulos, Mark L. Blaxter 2014, 'The complex hybrid origins of the root knot nematodes revealed through comparativegenomics', PeerJhttps://peerj.com/articles/356.pdf. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
The remaining members of the complex are regionally endemic, varying in their pest status and degree of polyphagy.
Aaron M. Dickey, Vivek Kumar, Mark S. Hoddle, Joe E. Funderburk, J. Kent Morgan, AntonellaJara-Cavieres, Robert G. Jr. Shatters, Lance S. Osborne, Cindy L. McKenzie 2015, 'The Scirtothrips dorsalis Species Complex: Endemism and Invasion in a Global Pest',PLOS ONE10.1371/journal.pone.0123747. Retrieved from PLOS CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)