DNA identifies invasive parasitic wasp
Like the creatures Sigourney Weaver battles in Alien, parasitoids are organisms whose larva develop in other species, usually leading to the death of the host. Insect parasitoids are widely used as biological control agents; sometimes these efforts go awry, threatening non-pest species in local ecosystems. Widespread introduction of tachnid fly parasitoid Compsilura concinnata has failed to control Gyspy moth Lymantra dispar outbreaks in eastern US, but has led to dramatic declines in large, showy Silk moths including the beautiful Luna moth Actias luna (Elkinton and Boettler. 2004).
About 10% of named insect species are parasitoids, mostly wasps, but recognizing these often minute insects can be tricky. In November 2007 Conservation Genetics researchers from Czech Academy of Sciences and University of South Bohemia, Czech Republic; Natural History Museum, London; and Imperial College London apply COI DNA sequencing to identify wasps parasitizing Canary Islands Large White butterfly Pieris cheiranthi, which is restricted to local endemic ecosystem of relict laurel forests. Lozan et al reared 55 P. cheiranthi caterpillars from 2 Canary Island sites, and found half of the larva from forest margin and none from central forest were parasitized with what appeared to be Cotesia glomerata, native to Europe and introduced elsewhere as biocontrol agent although not in Canary Islands.
3 of 600 C. glomerata-like adult wasps reared from Canary Island White larvae and 2 of 700 C. glomerata reared in Czech Republic from European Large White P. brassicae larvae were analyzed and found to have identical 5′ COI DNA sequences (this is the same region selected as a DNA barcode for animals). The authors conclude that European C. glomerata has been accidentally introduced to Canary Islands and is threatening a local endemic butterfly already under pressure from habitat loss. Without mentioning DNA barcoding by name, the authors conclude with a call for “increased effort to sequence morphological Costesia spp. from a broad geographical range…enabling the regular testing of species hypotheses…and the incorporation of all life stages using a single character set”. I hope that the authors can join forces and enable their sequences and associated metadata (eg collection location, specimen photographs, voucher information) from this and future Cotesia spp work to be usefully combined with growing COI barcode database (>415,000 COI barcode records from >41,000 species in BOLD so far, including 514 records from 89 named and provisional Cotesia spp). Looking ahead, routine application of DNA-based identification to parasitoids will help establish host ranges of potential biocontrol agents and detect inadvertent introduction of broad-range parasitoids that damage local ecosystems.
This entry was posted on Monday, July 7th, 2008 at 10:27 pm and is filed under General. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.
September 26th, 2015 at 8:21 am
Hi from the Canary Islands!
I have to say, that the Islands suffer a bit from the tourism – at least not directly. But there is all kind of stuff traveling with them, all kind of parasites which our flora is not prepared.
We also have some foreign plants here which starts to grow pretty wild