AbstractsBiology & Animal Science

The origin of Apatania zonella in Iceland: A study based on molecular and morphological variation

by Laurène Alicia Lecaudey




Institution: University of Iceland
Department:
Year: 2013
Keywords: Líffræði; Lækjabytta; Vorflugur
Record ID: 1221903
Full text PDF: http://hdl.handle.net/1946/17162


Abstract

This study focuses on the circumpolar species Apatania zonella (Zetterstedt 1840), a freshwater invertebrate from the order Trichoptera (caddisflies), living in cold streams, lakes and marshes. The species is widely distributed throughout the Arctic regions. As Iceland was fully covered by ice sheet during the last glacial maximum (LGM) 21 000 years ago, the current population of A. zonella in Iceland colonized the island after the last glaciation. Iceland is an interesting place for studying post glacial recolonization which started around 12.000 - 10.000 years ago, and species phylogeography due to its geographic position in the North Atlantic and its insular isolation. Several recent studies have shown evidences indicating that some Arctic species, including cold tolerant freshwater organisms, survived the LGM at high latitudes in cryptic refugia of the northern Palearctic within the permafrost areas. A. zonella is the only high Arctic Trichoptera species of Iceland indicating that this species had the potential ability to survive the LGM in northern refugia with harsher and colder conditions than the classically known refugia. The aim of this work is to provide information regarding the origin of the Icelandic population of A. zonella, by studying their genetic and morphological relationships with conspecifics from neighboring countries. The phylogenetic structure and genetic diversity of A. zonella, were determined based on fragments of the mitochondrial gene: CO1, and three nuclear genes: Cadherin-like protein (CAD), RNA polymerase II (POL) and isocitrate dehydrogenase (IDH). Additionally, the morphological variation was investigated by measuring and statistically comparing several key traits of the genitalia of female Apatania with respect to their origin, including flies from Greenland and A. hispida from Norway. The results from this study show that Iceland is an area of admixture or possibly a hybrid zone, colonized by at least two different lineages of A. zonella from Nearctic and Palearctic. Data analysis also revealed the lack of monophyly of A. zonella, indicating that the taxonomic status of this group should be re-evaluated. Finally, the morphological variations of the genital features allowed a good discrimination of the distinct populations into morphological and geographical groups. Þessi rannsókn fjallar um uppruna vorflugunnar lækjabyttu, Apatania zonella (Zetterstedt 1840) á Íslandi. Tegundin er dreifð umhverfis Norðurpól og lifir að miklu leyti sem lirfa í lækjum og vötnum. Þar sem Ísland var alþakið jökli við hámark ísþekju á síðasta kuldaskeiði fyrir um 21 þúsund árum, hefur lækjarbyttan numið land hér eftir að jöklar bráðnuðu og jafnvel eftir að síðasta kuldaskeiði lauk fyrir um 10 þúsund árum, rétt einsog nánast allar aðrar tegundir á Íslandi. Landnám Íslands og uppruni tegunda sem numu hér land er áhugavert rannsóknarefni vegna legu landsins, miðja vegu milli Ameríku og Evrópu. Ýmsar rannsóknir hafa sýnt merki um að arktískar tegundir, þ.á.m. kuldaþolnar ferskvatnstegundir, lifðu af á…