Differentiation of dispersive traits under a fluctuating range distribution in Asellus aquaticus
Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
Knowledge about dispersion is of utmost importance for understanding populations’ reaction to changes in the environment. Expansion of a population range brings with it both spatial sorting and over time, spatial selection. This means that dispersion rates increases over time at the expanding edge. Most studies have so far been performed on continuously expanding populations. This study aims to bring more knowledge about dispersal biology in dynamic systems. I studied dispersal traits in two permanent and two seasonal vegetation habitats of an isopod (Asellus aquaticus), for which differentiation between habitat types has previously been shown. I quantified differences in displacement (dispersal rate) and three morphological traits, head angle (body streamline) and leg of the third and seventh pair of legs. Isopods from the seasonal vegetation had higher displacement rates than animals from permanent vegetation. This inclines that mechanisms driving spatial selection in expanding population ranges also exist in dynamic systems. The more streamlined isopods found in seasonal sites further points towards spatial sorting by dispersion capability. Because no effect of permanence was found on leg length and there was no correlation between streamlining and displacement, the higher dispersion among animals from seasonal habitats most likely derives from behavioral differences.
Place, publisher, year, edition, pages
2014. , 17 p.
Asellus aquaticus, Dispersion, Dispersive traits, Habitats, Isopoda, Lake Tåkern, Spatial selection, Vegetation
Ecology Evolutionary Biology
IdentifiersURN: urn:nbn:se:liu:diva-108119ISRN: LITH-IFM-G-EX—14/2867—SEOAI: oai:DiVA.org:liu-108119DiVA: diva2:729279
Subject / course
2014-06-05, BL32 Nobel, Linköpings universitet 581 83, Linköping, 15:20 (Swedish)
Hargeby, Anders, UniversitetslektorLindström, Tom, Postdoktor
Bergman, Karl-Olof, Universitetslektor