Hybridization of two biotypes of Lilioceris cheni will not hinder biological control of air potato, Dioscorea bulbifera

Authors: Lake, Ellen; Smith, Melissa; OVERHOLT, WILLIAM - University Of Florida; DIAZ, RODRIGO - Louisiana State University; MANRIQUE, VERONICA - Louisiana State University; Dray, F Allen; ROHRIG, ERIC - Florida Department Of Agriculture And Consumer Services; Pratt, Paul

Submitted to: National Entomological Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/25/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary: Dioscorea bulbifera L. (Dioscoreales: Dioscoreaceae), air potato, is a perennial vine native to Asia and Africa that is invasive in Florida and other parts of the southeastern United States. Air potato vines can grow more than 20 meters long and outcompete native vegetation in a variety of habitats. The Chinese biotype of the biological control agent Lilioceris cheni Gressitt and Kimoto (Coleoptera: Chrysomelidae), the air potato leaf beetle, was first released in Florida in 2011. Later, a Nepalese biotype became available for release. The Chinese and Nepalese biotypes differ in aspects of their life history, including temperature dependent development. Ongoing experiments are evaluating their overwintering survival across a broad geographic range. Whether releasing Nepalese biotype beetles would benefit biological control of air potato is unknown. Therefore, we conducted laboratory experiments to evaluate the likelihood of assortative mating and whether hybridization would result in hybrid vigor or hybrid depression. The beetles exhibited no mate preference by biotype. Fecundity was compared between the following crosses: Chinese female x Chinese male, Nepalese female x Nepalese male, Chinese female x Nepalese male, and Nepalese female x Chinese male. In the F1 generation, fecundity was significantly higher in the Nepalese line than the Chinese line, and the hybrid lines did not differ from either. In the F2 generation, the Nepalese line and Chinese female x Nepalese male lines produced significantly more eggs than the Chinese line. We concluded that hybridization would not result in hybrid depression and field releases of the Nepalese biotype commenced.

Technical Abstract: Dioscorea bulbifera L. (Dioscoreales: Dioscoreaceae), air potato, is a perennial vine native to Asia and Africa that is invasive in Florida and other parts of the southeastern United States. Air potato vines can grow more than 20 meters long and outcompete native vegetation in a variety of habitats. The Chinese biotype of the biological control agent Lilioceris cheni Gressitt and Kimoto (Coleoptera: Chrysomelidae), the air potato leaf beetle, was first released in Florida in 2011. Later, a Nepalese biotype became available for release. The biotypes differ in aspects of their life history, including temperature dependent development, and ongoing experiments are evaluating their overwintering survival across a broad geographic range. Whether releasing Nepalese biotype beetles would benefit biological control of air potato is unknown. Therefore, we conducted laboratory experiments to evaluate the likelihood of assortative mating and whether hybridization would result in hybrid vigor or hybrid depression. The beetles exhibited no mate preference by biotype. Fecundity was compared between the following crosses: Chinese female x Chinese male, Nepalese female x Nepalese male, Chinese female x Nepalese male, and Nepalese female x Chinese male. In the F1 generation, fecundity was significantly higher in the Nepalese line than the Chinese line, and the hybrid lines did not differ from either. In the F2 generation, the Nepalese line and Chinese female x Nepalese male lines produced significantly more eggs than the Chinese line. We concluded that hybridization would not result in hybrid depression and field releases of the Nepalese biotype commenced.