Thesis
Comparing life history traits In native vs invasive asexual New Zealand mud snails
University of Iowa
Master of Science (MS), University of Iowa
Summer 2021
DOI: 10.17077/etd.005998
Abstract
Potamopyrgus antipodarum is a species of freshwater snail native to New Zealand that has invaded every continent aside from Antarctica and Africa. While native P. antipodarum populations are characterized by frequent coexistence between obligately sexual and obligately asexual individuals, only the asexual snails are known to invade other ecosystems. Despite very low genetic diversity and the absence of sex, invasive asexual P. antipodarum are highly successful. Here, I quantified variation in three key life-history traits across invasive P. antipodarum lineages and compared this variation to already documented variation in these same traits in asexual native lineages to provide a deeper understanding of why some lineages become invasive. In particular, I evaluated 1) if invasive lineages of P. antipodarum could be successful because they represent life-history variation from native ancestors that is optimal for invasions and 2) if invasive populations with higher genetic variation would display more phenotypic variation than populations with lower genetic variation. I found that the distribution of phenotypic variation between the native and invasive snails was different, with invasive snails growing more slowly and maturing more rapidly than their native counterparts. I did not find any significant differences in size at maturity between the invasive and native snails. These results are consistent with expectations of a scenario where invasive lineages represent a subset of native variation that is beneficial in the setting of invasion. Nevertheless, there was no evidence for a relationship between genetic and phenotypic variation, indicating that increased genetic variation does not necessarily translate into greater phenotypic variation, and consistent with earlier studies suggesting an important role for phenotypic plasticity in invasion. Together, these results provide new insights into the mechanisms driving the worldwide expansion of invasion populations of these snails.
Details
- Title: Subtitle
- Comparing life history traits In native vs invasive asexual New Zealand mud snails
- Creators
- Carina Donne
- Contributors
- Maurine Neiman (Advisor)Andrew Forbes (Committee Member)Stephen Hendrix (Committee Member)
- Resource Type
- Thesis
- Degree Awarded
- Master of Science (MS), University of Iowa
- Degree in
- Biology
- Date degree season
- Summer 2021
- DOI
- 10.17077/etd.005998
- Publisher
- University of Iowa
- Number of pages
- viii, 28 pages
- Copyright
- Copyright 2021 Carina Donne
- Language
- English
- Description illustrations
- color illustrations
- Description bibliographic
- Includes bibliographical references (pages 23-28)
- Public Abstract (ETD)
Biological invasions are a worldwide problem, causing significant declines in biodiversity and severe economic losses. Furthering our understanding of biological invasions will not only provide insight into the mechanisms that drive invasion success but will also help provide a framework for robust management of invasions. An important question in biology is why some species and even lineages within species become invasive. The potential key to understanding invasions could be studying life-history traits which are important determinants of fitness. Here, I studied life-history traits in the New Zealand freshwater snail, Potamopyrgus antipodarum. This asexual snail has invaded every continent except for Antarctica and Africa despite having low genetic variation. I focused on three life-history traits of growth rate, age at maturity and size at maturity. I also used previously collected genetic data to see if having higher genetic variation would lead to higher life-history trait variation. I was able to make direct comparisons to previously documented work of life-history traits in native asexual P. antipodarum. I found that the invasive snails grew more slowly and matured earlier than the native snails. I did not find any significant differences in size at maturity between the invasive and native snails. Furthermore, I did not find a relationship between genetic variation and life-history trait variation indicating there are other factors at play. Altogether, my results suggest that life-history traits of growth rate and age at maturity are important for the invasion success of P. antipodarum. This study provides new insights into the mechanisms driving invasion success and has implications for management efforts of preventing and containing the further spread of these invasive snails.
- Academic Unit
- Biology
- Record Identifier
- 9984124360902771
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