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@PHDTHESIS{Siddique:961287,
author = {Siddique, Ayesha},
othercontributors = {Ließ, Matthias Erwin Fritz and Schäffer, Andreas},
title = {{L}iving on the edge: adaptation to pesticides and
associated fitness costs},
volume = {2023,2},
school = {RWTH Aachen University},
type = {Dissertation},
address = {Aachen},
publisher = {RWTH Aachen University},
reportid = {RWTH-2023-06744},
series = {Dissertation / Helmholtz Centre for Environmental
ResearchUFZ-Dissertation /PhD-Dissertation},
pages = {1 Online-Ressource : Illustrationen},
year = {2023},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University; Dissertation, RWTH Aachen University, 2023},
abstract = {Abstract The decline of sensitive species in agricultural
streams is mainly attributed to pesticide contamination,
even below the regulatory acceptable concentrations. Very
low toxic pressure may thus determine ecological and
evolutionary processes responsible for the current loss in
biodiversity, and leading to adaption at community and
individual level. In order to improve the current risk
assessment, this dissertation aims to analyze factors that
may shape the response of organisms to chemicals in the
field. To analyze the effect of long-term exposure to low
pesticide concentrations in natural populations, a field
investigation was conducted (Chapter 2). We observed that
populations from contaminated streams were up to 2.5-fold
more tolerant to clothianidin. However, populations showing
increased insecticide tolerance were characterized by
reduced survival, per capita growth and mating when cultured
under pesticide free conditions. Given that multi-stress
conditions may occur more often under global change
scenarios, the adaptation to one stressor might shape the
response to another stressor (Chapter 3). We observed that
agricultural populations are on average 2-fold more tolerant
to insecticide clothianidin as compared to reference
populations. After experimental pre-exposure to very low
concentration (LC50/ 1000), only reference populations
showed increased pesticide tolerance. Under multiple stress
of pesticides and elevated temperature, both reference and
agricultural populations showed a similar tolerance to the
combined stress of pesticides and warming due to stronger
synergistic effects in adapted populations. However,
agricultural populations were more sensitive to elevated
temperature alone due to the hypothesized fitness cost of
genetic adaptation to pesticides and as a result, pesticide
adaptation loses its advantage. Although pesticide tolerance
enables the survival of tolerant species in contaminated
streams, long-term exposure to pesticides may alter their
genetic structure (Chapter 4). G. pulex collected from 38
small streams showed that pesticide exposure increased the
pesticide tolerance, reduced Abstract the genetic diversity,
resulted in an adopted genetic composition and compromised
individual fitness in locally adapted populations.
Specifically, an increased frequency of “high
contamination alleles” and a decrease of “low
contamination alleles” was observed with increasing
contamination. Furthermore, the individual per capita growth
decreased with increasing trade-offs of genetic adaptation.
Nevertheless, G. pulex contributed an average of $44\%$ of
macroinvertebrate abundance and benefited from reduced
interspecific competition with vulnerable species in
contaminated streams. Condering global change scenario and
persistent stress leading to adaptation, the question
arises: How can the combined effects of these apparently
contradictory processes be predicted (Chapter 5)? We show
that pesticide adapted G. pulex from agricultural streams
were more tolerant to pesticides (clothianidin, prochloraz)
as compared to nonadapted populations. However, joint
exposure to both pesticides and temperature stress resulted
in acute synergistic interactions, and the combined effects
were stronger in adapted populations. We hypothesize that
the pesticide adaptation reduces general stress capacity of
individuals and trade-off process increases sensitivity to
the combined stress. The general stress exerted by each of
the individual factors was quantified using the Stress
Addition Model (SAM). These studies showed that pesticide
pollution triggers adaptation from sub-organismal to
community level. Unraveling these processes explains effects
from genes to ecosystem level.},
cin = {160000 / 164120},
ddc = {570},
cid = {$I:(DE-82)160000_20140620$ / $I:(DE-82)164120_20160614$},
typ = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
doi = {10.18154/RWTH-2023-06744},
url = {https://publications.rwth-aachen.de/record/961287},
}
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