Two Suaeda species were planted recently in the 'En Gedi' oasis plot: Suaeda vera and Suaeda fruticosa, belonging to the family Amaranthaceae (until recently the Chenopodiaceae). The two species were used in a study conducted in Dr Netta Dorchin’s laboratory at the School of Zoology, in which insect-plant interactions in gall-inducing insects (gall midges) were examined.* Adult gall midges lay their eggs on or inside the plant tissues and the hatching larvae feed on the tissues and cause the development of the gall, in which they complete their development. Like most gall-forming insects, gall midges are specialists and usually induce galls on one species or several related species of plants. Suaeda species grow in salt marshes and deserts and are notoriously difficult to identify because different species are morphologically very similar. In some cases, the specific galls induced by gall midges on certain Suaeda species facilitate identification of the plants! During the study, the plants were exposed to gall midges in order to document the preference of the midges for egg-laying and the rates of success in gall development on different Suaeda species. In one case it was discovered that a gall-midge species that develops on Suaeda asphaltica and Suaeda fruticosa is in the process of splitting into two separate populations – each on its own host plant, which may eventually lead to the formation of two separate species This is yet another (local) example of the importance of insect-plant interactions in generating biodiversity in nature.

* A gall is a controlled growth generated in plant tissues, usually as a result of insect activity.