Minimum threshold for establishment and dispersal of Lilioceris cheni (Coleoptera: Chrysomelide): a biological control agent of Dioscorea bulbifera

Authors: Lake, Ellen; Smith, Melissa; Rayamajhi, Min; Pratt, Paul; Dray, F Allen

Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/11/2018
Publication Date: 5/5/2018
Citation: Lake, E.C., Smith, M., Rayamajhi, M.B., Pratt, P.D., Dray Jr, F.A. 2018. Minimum threshold for establishment and dispersal of Lilioceris cheni (Coleoptera: Chrysomelide): a biological control agent of Dioscorea bulbifera. Biocontrol Science and Technology. 28(6):603-613. https://doi.org/10.1080/09583157.2018.1468999.
DOI: https://doi.org/10.1080/09583157.2018.1468999

Interpretive Summary: The successful establishment or failure of a new population is often attributed to propagule pressure, the combination of the number of independent introduction events, and the number of individuals released at each event. In order to design an optimal release strategy for a biological control agent it is important to understand the impact of propagule pressure on the species being released. The dispersal rate of individuals from new populations can also affect establishment success. We assessed the minimum threshold for establishment and measured dispersal of Lilioceris cheni (Coleoptera: Chrysomelidae) a biological control agent for Dioscorea bulbifera (Dioscoreales), air potato. Replicated releases of 10, 50, and 100 adults of L. cheni were conducted on the east and west coasts of south Florida. Dispersal was also measured from 19 of these sites plus from 19 additional release locations in south and central Florida. Lilioceris cheni established populations from all three release sizes with no apparent influence of site location. Beetles dispersed an average of 1.41 ± 0.515 km / yr. The distance dispersed was significantly affected by the time since release but not the number of individuals released. Eighty-five percent of releases of 100 adults established. Our results suggest that future releases could be spaced several kilometers apart on the landscape to facilitate rapid colonization of D. bulbifera infestations.

Technical Abstract: The successful establishment or failure of a new population is often attributed to propagule pressure, the combination of the number of independent introduction events, and the number of individuals released at each event. Design of optimal release strategies for biological control agents benefits from an understanding of the impact of propagule pressure on the species being released. The dispersal rate of individuals from nascent population foci can also affect establishment success. We assessed the minimum threshold for establishment and measured dispersal of Lilioceris cheni (Coleoptera: Chrysomelidae) a biological control agent for Dioscorea bulbifera (Dioscoreales), air potato. Replicated releases of 10, 50, and 100 adults of L. cheni were conducted on the east and west coasts of south Florida. Dispersal was measured from 19 of these sites plus 19 additional release locations in south and central Florida. Lilioceris cheni established populations from all three release sizes with no apparent influence of site location. Beetles dispersed an average of 1.41 ± 0.515 km / yr. The distance dispersed was significantly affected by the time since release but not the number of individuals released. Eighty-five percent of releases of 100 adults established and our results suggest that future releases could be spaced several kilometers apart on the landscape to facilitate rapid colonization of D. bulbifera infestations.