sex determination; fish; salmonids; global warming; demographics; evolution; ecology; genetics; experimental breeding; minnow (Phoxinus phoxinus)
dos Santos M, Rodrigues JFM, Wedekind C, Rankin DJ (2012), The establishment of communication systems depends on the scale of competition, in EVOLUTION AND HUMAN BEHAVIOR
, 33(3), 232-240.
Wedekind C (2012), Managing population sex ratios in conservation practice: how and why?, in Povilitis T (ed.), InTech Open Access Publisher, Rijeka, Croatia, 81-96.
dos Santos M, Wedekind C (2012), Examining punishment at different explanatory levels, in BEHAVIORAL AND BRAIN SCIENCES
, 35(1), 23-24.
Nussle S, Brechon A, Wedekind C (2011), Change in individual growth rate and its link to gill-net fishing in two sympatric whitefish species, in EVOLUTIONARY ECOLOGY
, 25(3), 681-693.
dos Santos M, Rankin DJ, Wedekind C (2011), The evolution of punishment through reputation, in PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
, 278(1704), 371-377.
Wedekind C (2011), Darwin et la biologie de la conservation. Une vision évolutionniste de la protection des espèces, in Hotspot (Forum Biodiversité Suisse)
, 19, 14-15.
Jacob A, Evanno G, von Siebenthal BA, Grossen C, Wedekind C (2010), Effects of different mating scenarios on embryo viability in brown trout, in MOLECULAR ECOLOGY
, 19(23), 5296-5307.
Cotton S, Wedekind C (2010), Male Mutation Bias and Possible Long-Term Effects of Human Activities, in CONSERVATION BIOLOGY
, 24(5), 1190-1197.
Wedekind C, Kung C (2010), Shift of Spawning Season and Effects of Climate Warming on Developmental Stages of a Grayling (Salmonidae), in CONSERVATION BIOLOGY
, 24(5), 1418-1423.
Wedekind C, Evanno G (2010), Mate choice, the major histocompatibility complex, and offspring viability, in Muehlenbein MP (ed.), Cambridge University Press, Cambridge, UK, 309-321.
Wedekind C, Gessner MO, Vazquez F, Maerki M, Steiner D (2010), Elevated resource availability sufficient to turn opportunistic into virulent fish pathogens, in ECOLOGY
, 91(5), 1251-1256.
Wedekind C (2010), Searching for sex-reversals to explain population demography and the evolution of sex chromosomes, in MOLECULAR ECOLOGY
, 19(9), 1760-1762.
Wedekind C, Pompini M (2010), Salmonid embryos influenced by symbiotic microbes, in Bulletin of the Ecological Society of America
, 91, 230-231.
Stelkens RB, Wedekind C (2010), Environmental sex reversal, Trojan sex genes, and sex ratio adjustment: conditions and population consequences, in MOLECULAR ECOLOGY
, 19(4), 627-646.
Rankin DJ, dos Santos M, Wedekind C (2009), The evolutionary significance of costly punishment is still to be demonstrated, in PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
, 106(50), 135-135.
Wedekind C, Stelkens RB (2009), Tackling the diversity of sex determination, in Biology Letters
, 6, 7-9.
Nussle S, Bornand CN, Wedekind C (2009), Fishery-induced selection on an Alpine whitefish: quantifying genetic and environmental effects on individual growth rate, in EVOLUTIONARY APPLICATIONS
, 2(2), 200-208.
Jacob A, Evanno G, Renai E, Sermier R, Wedekind C (2009), Male body size and breeding tubercles are both linked to intrasexual dominance and reproductive success in the minnow, in ANIMAL BEHAVIOUR
, 77(4), 823-829.
von Siebenthal BA, Jacob A, Wedekind C (2009), Tolerance of whitefish embryos to Pseudomonas fluorescens linked to genetic and maternal effects, and reduced by previous exposure, in FISH & SHELLFISH IMMUNOLOGY
, 26(3), 531-535.
Cotton S, Wedekind C (2009), Population Consequences of Environmental Sex Reversal, in CONSERVATION BIOLOGY
, 23(1), 196-206.
Wedekind C (2009), Darwin und die Naturschutzbiologie. Eine evolutionäre Sicht auf den Artenschutz, in Hotspot (Forum Biodiversität Schweiz)
, 19, 14-15.
Clark ES, Wedekind C, Additive genetic effects on embryo viability in a whitefish (Salmonidae) influenced by the water mould Saprolegnia ferax, in Journal of Bacteriology and Parasitology
Stelkens RB, Jaffuel G, Escher M, Wedekind C, Data from: Genetic and phenotypic population divergence on a microgeographic scale in brown trout, in Dryad Digital Repository
Stelkens RB, Jaffuel G, Escher M, Wedekind C, Genetic and phenotypic population divergence on a microgeographic scale in brown trout., in Molecular Ecology
Background - Sex determination in fish is often genetic, with many species relying on the segregation of sex chromosomes for assignment of gender. However, the phenotypic sex can be modified by environmental influences after fertilization. Sex hormones or hormone mimics, endocrine-disrupting chemicals, and even water temperatures or pH above or below normal during a discrete period after conception can induce environmental sex reversal (ESR) and thereby create biased sex ratios. Information on the physiological and reproductive consequences of such environmental changes is accumulating, and there seems to be an increasing recognition that environmental factors may induce sex reversal in many natural fish populations. However, the conditions for ESR in fish are not well understood yet. Moreover, the prevalence of ESR in natural populations, its fitness effects relative to genetic and maternal environment effects, and hence its consequences on population demography, population genetics, and the potential for an evolutionary response to ESR are largely unknown. First theoretical treatments of the issue concluded that ESR can have dramatic effects on the demographics of a population and on the evolution of sex-linked genes or chromosomes. On the one hand, such effects can directly threaten natural populations. Indeed, first field observations suggest that ESR happens in several salmonid populations, including a Swiss population of grayling (Thymallus thymallus) in which we found dramatically distorted sex ratios that are linked to changed temperatures at the time when sex determination happens, and that could potentially explain an otherwise unexplained population decline. On the other hand, ESR can potentially be used to control invasive species like the goldfish (Carassius auratus) or the pumpkinseed sunfish (Lepomis gibbosus) in the pre-Alpine region, or the European minnow (Phoxinus phoxinus) and the brown trout (Salmo trutta) in other parts of the world: repeated introduction of, for example, YY-females could produce extreme male-biased sex ratios and thereby lead to population decline or extinction (the “Trojan Y-chromosome hypothesis”). Working Hypotheses - Sex determination in various fish species of the pre-Alpine region is influenced by changed temperature regimes and by other environmental factors. This affects population demographics, genetics, and evolution. ESR not only threatens some natural populations but can also be used to control invasive species by introduction of sex-reversed individuals.Specific Aims - We will experimentally study the conditions for ESR and the associated fitness costs in various populations of graylings, brown trout, whitefish (Coregonus sp.), and minnows of the pre-Alpine region. Our first three study species are members of the charismatic and economically important family Salmonidae, i.e. of a family that has been well studied with regard to physiology, genetics, ecology, behavior, and evolution. We therefore consider them as excellent model species - like the minnow that is one of the best-studied members of the large family Cyprinidae. Quantitative estimates of key factors will be used to build data based models that explore the population consequences and the possible evolution of ESR in natural populations. We will also explore the potential of ESR for controlling fish species that are considered invasive in the pre-Alpine region or in other parts of the world.Experimental Design and Methods - We will draw representative samples of breeders from various natural populations. Full-factorial in vitro breeding experiments and the raising of offspring under various experimental conditions in the laboratory, under various field conditions, and in experimental ponds will allow us to study the within- and between- population variation in the conditions for, and the consequences of, ESR. We will also record the prevalence in ESR in the wild by inference from our breeding experiments and by analyzing the findings of ongoing monitoring programs.Expected Value of the Proposed Project - ESR may become increasingly relevant with greater anthropogenic interferences on watercourses and with changing global and local temperatures. Our research will close important gaps in our understanding of sex determination in various fish that are not only model species for various fields of basic research but also ecological keystone species in their respective habitats. Our research will provide a scientific basis for possible countermeasures in the case of populations that are declining because of ESR or that are threatened by ESR. It will also provide a scientific basis for possible exploitation of ESR to control invasive species that are threatening existing species communities in various parts of the world, including Switzerland.