Saltcedar (Tamarix sp.) is an invasive riparian shrub/tree in the western United States which displaces native plants, increases soil salinity and wildfires, lowers water tables, and reduces water availability for agriculture. Diorhabda elongata (Coleoptera: Chrysomelidae) feeds exclusively on saltcedar in Europe and Asia. Ecotypes from Fukang, China and Crete, Greece have been released in the western United States. Fukang has established in northern locations and Crete populations are increasing in southern locations. It is likely distributions of these ecotypes will overlap in the future. The objective of this experiment was to determine the effects of mixing populations of Fukang and Crete ecotypes.

Fukang and Crete ecotypes will mate and produce viable eggs when confined; however, all of the F₁ offspring are sterile. The consequences of hybrid matings could disrupt long-term population dynamics in a mixed field population, slowing population growth or causing localized extinction of one ecotype. While it is still unknown if either the Fukang ecotype or the Crete ecotype will migrate, we know in a no-choice controlled environment the two ecotypes will readily mate with each other.

Population and mating experiments were carried out in six field cages which consisted of three different treatments; pure Crete, pure Fukang, and mixed Crete and Fukang. Each cage was monitored for the number of adults, eggs and larvae. Saltcedar was monitored for growth and defoliation. Amplified Fragment Length Polymorphism techniques were used to confirm levels of hybridization.