Effects of insect invasions
Two databases (http://www.issg.org/database/welcome/, GISD (Global Invasive Species Database) and http://www.europe-aliens.org/, DAISIE (Delivering Alien Invasive Species Inventories for Europe)) provide a «top 100» list of the worst invasive species. GISD only includes one species per genus, to ensure the inclusion of a wide range of examples. Although it is very difficult to identify 100 invasive species from around the world that really are "worse" than any others, species were selected for the list according to two criteria: the seriousness of their impact on biological diversity and/or human activities, and their illustration of important issues surrounding biological invasion. In DAISIE, the «100 of the worst» invasive aliens in Europe identified cover a broad spectrum of life forms and represent some of the worst species in terms of their impact on biodiversity, economy and health. Additional and regularly updated information (datasheets on more than 9,000 invasive species) can be obtained from the Invasive Species Compendium, hosted by CABI (Centre for Agricultural Bioscience International), at http://www.cabi.org/isc/.
Which of the insects mentioned below are among the "top 100" in any of the databases? Choose the worst ones, and click on the pictures below, then read the explanations!
Bemisia tabaci and Aedes albopictus are listed by both ISSG and DAISIE as being among the «top 100» worst invasive species. Harmonia axyridis is among the «top 100» worst invasive species only according to DAISIE. Adelges tsugae is not listed among the «worst 100» invasive species. Dacus ciliatus is not listed in any of these databases, but Ceratitis capitata, another fly of the Tephritidae family, is ranked among the «top 100» invasive species by DAISIE. Dendroctonus ponderosae has not yet appeared outside its geographic range (western USA, British Columbia and southwestern Alberta, Canada, and Baja California, Mexico), and can therefore only be considered as potentially invasive (http://www.cabi.org/isc/datasheet/18354, last modified June 2015).