The dynamics of a tephritid seed predator on Tripolium vulgare in a stochastic and heterogeneous environment

In this thesis the factors regulating the interaction between the seed predatory fly Paroxyna plantaginis (Diptera: Tephritidae) and its host plant Tripolium vulgare, (former Aster tripolium, Asteraceae) are determined and evaluated. The host is patchily distributed on islands in the study area (the...

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Main Author: Riber Albrectsen, Benedicte
Format: Doctoral or Postdoctoral Thesis
Language:English
Published: 2000
Subjects:
Online Access:https://pub.epsilon.slu.se/17687/
https://pub.epsilon.slu.se/17687/1/riber_albrectsen_b_201005.pdf
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spelling ftslunivuppsala:oai:pub.epsilon.slu.se:17687 2023-05-15T17:45:14+02:00 The dynamics of a tephritid seed predator on Tripolium vulgare in a stochastic and heterogeneous environment Riber Albrectsen, Benedicte 2000 application/pdf https://pub.epsilon.slu.se/17687/ https://pub.epsilon.slu.se/17687/1/riber_albrectsen_b_201005.pdf en eng eng https://pub.epsilon.slu.se/17687/1/riber_albrectsen_b_201005.pdf Riber Albrectsen, Benedicte (2000). The dynamics of a tephritid seed predator on Tripolium vulgare in a stochastic and heterogeneous environment. Diss. (sammanfattning/summary) Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae. Silvestria, 1401-6230 ISBN 91-576-5890-0 [Doctoral thesis] Ecology Doctoral thesis NonPeerReviewed info:eu-repo/semantics/doctoralThesis 2000 ftslunivuppsala 2022-01-09T19:15:26Z In this thesis the factors regulating the interaction between the seed predatory fly Paroxyna plantaginis (Diptera: Tephritidae) and its host plant Tripolium vulgare, (former Aster tripolium, Asteraceae) are determined and evaluated. The host is patchily distributed on islands in the study area (the archipelago of Skeppsvik 63°44-48' N, 20°34-40'E) in northern Sweden. Possible factors that may cause the persistence of this system include direct density-dependent feedback processes, temporal and spatial heterogeneity, and the effect of stochasticity (chance). The impact of these forces is analysed through both pattern and process approaches, concentrating on the spatial and temporal distribution of the resource and the timing and dispersal of the fly, as well as the influence of stochasticity. Relating attack frequencies to host density showed no strong indication of tight regulation between the specialist seed predator and its host plant (Paper I). Smaller plants and subpopulations were subject to the highest variation in attack frequency, suggesting that there is a strong element of chance influencing the risk of attack. There were, however, indications of a spatial effect at low fly densities, which seemed to break down at higher densities, implying that dispersal behaviour and strength may be related to adult fly density. The fragmented resource is more evenly used at higher attack frequencies (Paper II) : an effect which may be coupled directely to fly densities (Paper III). A mismatch between the phenology of the fly and the sea aster flowering phenology seems to benefit the first flowering flower heads, which are less often attacked in a normal year (Paper III) . However, it was experimentally shown that the flies compensate for the temporal and spatial unpredictability by a female-biased density-dependent dispersal (Paper IV). Density-independent water-borne dispersal during the puparia stage may also affect the dynamics of the tephritid (Paper V). This system is an example of a highly persistent interaction, for which stochastic and spatial effects are of major importance. The density-dependent dispersal of females may act within generations in the spatially heterogeneous environment and this may be transformed from a local response to a mode of regulation that works between generations. Doctoral or Postdoctoral Thesis Northern Sweden Swedish University of Agricultural Sciences (SLU): Epsilon Open Archive
institution Open Polar
collection Swedish University of Agricultural Sciences (SLU): Epsilon Open Archive
op_collection_id ftslunivuppsala
language English
topic Ecology
spellingShingle Ecology
Riber Albrectsen, Benedicte
The dynamics of a tephritid seed predator on Tripolium vulgare in a stochastic and heterogeneous environment
topic_facet Ecology
description In this thesis the factors regulating the interaction between the seed predatory fly Paroxyna plantaginis (Diptera: Tephritidae) and its host plant Tripolium vulgare, (former Aster tripolium, Asteraceae) are determined and evaluated. The host is patchily distributed on islands in the study area (the archipelago of Skeppsvik 63°44-48' N, 20°34-40'E) in northern Sweden. Possible factors that may cause the persistence of this system include direct density-dependent feedback processes, temporal and spatial heterogeneity, and the effect of stochasticity (chance). The impact of these forces is analysed through both pattern and process approaches, concentrating on the spatial and temporal distribution of the resource and the timing and dispersal of the fly, as well as the influence of stochasticity. Relating attack frequencies to host density showed no strong indication of tight regulation between the specialist seed predator and its host plant (Paper I). Smaller plants and subpopulations were subject to the highest variation in attack frequency, suggesting that there is a strong element of chance influencing the risk of attack. There were, however, indications of a spatial effect at low fly densities, which seemed to break down at higher densities, implying that dispersal behaviour and strength may be related to adult fly density. The fragmented resource is more evenly used at higher attack frequencies (Paper II) : an effect which may be coupled directely to fly densities (Paper III). A mismatch between the phenology of the fly and the sea aster flowering phenology seems to benefit the first flowering flower heads, which are less often attacked in a normal year (Paper III) . However, it was experimentally shown that the flies compensate for the temporal and spatial unpredictability by a female-biased density-dependent dispersal (Paper IV). Density-independent water-borne dispersal during the puparia stage may also affect the dynamics of the tephritid (Paper V). This system is an example of a highly persistent interaction, for which stochastic and spatial effects are of major importance. The density-dependent dispersal of females may act within generations in the spatially heterogeneous environment and this may be transformed from a local response to a mode of regulation that works between generations.
format Doctoral or Postdoctoral Thesis
author Riber Albrectsen, Benedicte
author_facet Riber Albrectsen, Benedicte
author_sort Riber Albrectsen, Benedicte
title The dynamics of a tephritid seed predator on Tripolium vulgare in a stochastic and heterogeneous environment
title_short The dynamics of a tephritid seed predator on Tripolium vulgare in a stochastic and heterogeneous environment
title_full The dynamics of a tephritid seed predator on Tripolium vulgare in a stochastic and heterogeneous environment
title_fullStr The dynamics of a tephritid seed predator on Tripolium vulgare in a stochastic and heterogeneous environment
title_full_unstemmed The dynamics of a tephritid seed predator on Tripolium vulgare in a stochastic and heterogeneous environment
title_sort dynamics of a tephritid seed predator on tripolium vulgare in a stochastic and heterogeneous environment
publishDate 2000
url https://pub.epsilon.slu.se/17687/
https://pub.epsilon.slu.se/17687/1/riber_albrectsen_b_201005.pdf
genre Northern Sweden
genre_facet Northern Sweden
op_relation https://pub.epsilon.slu.se/17687/1/riber_albrectsen_b_201005.pdf
Riber Albrectsen, Benedicte (2000). The dynamics of a tephritid seed predator on Tripolium vulgare in a stochastic and heterogeneous environment. Diss. (sammanfattning/summary) Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae. Silvestria, 1401-6230 ISBN 91-576-5890-0 [Doctoral thesis]
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