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ID: 232330.1, MPI für Evolutionsbiologie / Evolutionary ecology
Food and parasites - life-history decisions in copepods
Advisors:Kraaijeveld, Alex Robert
Authors:Sivars Becker, Lena
Language:English
Date of Approval (YYYY-MM-DD):2004-05-26
Name of University:Uppsala University
Place of University:Uppsala
Physical Description
(e.g. Total Number of Pages):
40 Bl.
Audience:Not Specified
Table of Contents:Introduction................................................7
Body size.................................................8
Current vs. future reproduction...........................9

Aim........................................................11

Study species..............................................12
The parasite.............................................13
General methods..........................................15

Results and Discussion.....................................17
Age and size at maturity - paper I.......................17
Resource allocation in males - paper II..................19
Female life-histories and food availability - paper III..21
A field study - paper IV.................................23
Resource allocation and cost of infection in females -
paper V................................................. 25

Conclusion.................................................28

Acknowledgments............................................30

Sammanfattning.............................................32

References.................................................36
Abstract / Description:In the freshwater copepod, Macrocyclops albidus, food availability, rearing conditions and tapeworm infection clearly affected various life-history traits and their trade-offs. I found that low food availability clearly constrained resource allocations to several life-history (often phenotypically plastic) traits, whereas high food availability either allowed for adjustments in resource allocation patterns or allowed to be allocated to several traits withou apparent trade-offs.
Both maile and female copepods allocated resources according to food availability; developing more slowly and achieving smaller adult body size when food was scarce. When food availability was low females were constrained and produced fewer eggs (in total and per clutch), and started reproduction later than females with more food available. Males under low food availability allocated reletively more spermatophore size (current reproduction) with decreasing body size. In contrast, when food availability was high males allocated resources to body size as well as spermatophore size. Overall, at maturity, copepods of both sexes were more similar in size than in age, suggesting that large body size was more important for fitness than fast development.
In nature the prevalence of copepods infected with cestode tapeworms was found to be low (0-3%). Female copepods, experimentally infected with the cestode Schistocephalus solidus, showed lower overall fecundity, especially when food availability was low. However, infected females produced a larger proportion of their life-time egg production early in life than non-infected females. This might be an adaptation to reduce future fitness costs of infection. Females grown under bad rearing conditions, but with high food availability, produced their first clutch earlier than females grown under good rearing conditions, indicating an adjustment in timing reproduction. These findings contribute to our fundamental evolutionary understanding of how environmental conditions interact with life-history traits.
Free Keywords:life-history; resource allocation; Macrocyclops albidus; cestode infection; Schistocephalus solidus
Comment of the Author/Creator:Published in:
Acta Universitatis Upsaliensis. Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology Nr 979, 2004
Document Type:PhD-Thesis
Affiliations:MPI für Limnologie/Abt. Evolutionsökologie
External Affiliations:Department of Ecology and Evolution, Department of Animal Ecology, Norbyv 18 D, Uppsala University, SE-75236 Uppsala, Sweden
Identifiers:ISBN:91-554-5971-4 [ID-Nr.:1]
ISSN:1104-2322X [ID-Nr.:2]
URL:http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-42... [ID-Nr.:3]
LOCALID:Diss/11085 [Signatur/Zugangsnummer]
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