A review of West Palaearctic species of the genus Eloeophila Rondani, 1856 is presented. Three species are redescribed, viz. E. czernyi (Strobl in Czerny & Strobl, 1909), E. laciniata (Edwards, 1928), and E. pusilla (Kuntze, 1920). A lectotype of the latter is designated. Eloeophila albofascia (Alexander, 1975) is established as a new junior synonym of E. apicata (Loew, 1871). Descriptions are provided of E. bipartita sp. n. (North Italy), E. delmastroi sp. n. (North Italy), E. lucasi sp. n. (South Italy and Sicily), E. maroccana sp. n. (Morocco, Spain), E. martinovskyi sp. n. (South Italy), E. minor sp. n. (Czech Republic, Slovakia), E. pectinistylus sp. n. (Spain), E. punctulata sp. n. [Cyprus, Greece (Crete)], E. sparsipunctum sp. n. (Bulgaria), and E. tigricosta sp. n. (Spain). A key to males of all West Palaearctic species is presented.
To understand the evolution of insect gut symbionts it is important to determine how they are passed on to the next generation. We studied this process in Erwinia species bacteria that inhabit the gut of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). This is a polyphagous herbivore and a world-wide pest in agricultural crops. With bacteria in the gut, the thrips larval development time can be shorter and its oviposition rate higher compared to bacteria-free thrips. Bacteria are not directly transmitted from mother to offspring, but larvae acquire bacteria from the leaves right after they hatch. These gut bacteria are present on the leaves on feeding sites used by other thrips before the larvae arrive, probably because these other thrips have deposited bacteria via faeces or regurgitation. In this study we addressed the question whether the transmission route of symbiotic bacteria influences the thrips feeding behaviour, and determined the feeding and oviposition preference of thrips, by giving them a choice between leaves with and leaves without prior grazing by other western flower thrips. This was studied for thrips with and thrips without gut bacteria. Young larvae prefer to feed on leaves that where grazed before by other thrips and females prefer to oviposit on these grazed leaves. These results are in contradiction to earlier studies that have found that thrips larvae fitness is lower on thrips damaged plants than on clean plants. This behaviour does however promote the establishment of gut bacteria in the thrips. The factors determining the preference for thrips-damaged leaves may be the physical leaf damage or odours that are produced by the plant, the bacteria or both.