THE EFFECTS OF INBREEDING ON MATE CHOICE   During my PhD I am studying inbreeding and inbreeding avoidance in the guppy, Poecilia reticulata. I focus on the negative effects of inbreeding (inbreeding depression) on male traits such as sperm quantity, fertilisation success, mating behaviour and ornamentation, and investigate the potential evolution of mechanisms for inbreeding avoidance in females. For this, I conduct behavioural mating trials investigating the interplay between sexual selection (and specific preferences for male ornamental traits) and context-dependent factors such as familiarity, relatedness and male pattern rarity.   Male guppies are extremely polymorphic in their ornamentation, displaying a wide range of colourful ornaments including black, orange and iridescent spots on body and tail, and also vary in tail and fin shapes and sizes. Many of these traits are paternally inherited, which allows breeding similar looking related males and testing for frequency-dependent preferences of females. Also, breeding males in pedigrees using in- and outbred lines allows the direct comparison of effects on inbreeding on ornamental traits, and investigation of female preferences for in- or outbred males.   Female preferences for ornamentation have been shown to vary widely in the guppy, and seem to be population-specific. Potentially, context-dependent traits may influence the sexual selection that females pose upon male ornamental traits, which is one of the key  questions I try to answer during my candidature.   Inbreeding avoidance mechanisms such as the preferences for outbred, unrelated or unfamiliar males or males with rare patterns are likely to evolve is fitness deficits following inbreeding are substantial. Moreover, those preferences might also increase the mating success of immigrants, and may have evolved to facilitate the avoidance of inbreeding. Together with the high variability of female preferences for ornament combinations, it also offers an explanation for the maintenance of polymorphism in this species.

2004 - 2008 PhD candidature at UNSW, Sydney.
2007 Birth of son Julius
2002 - 2003 Diploma thesis at LMU, Munich, Germany.
1996 - 2001 Studies in Biology at LMU Munich, Germany, and Life Sciences at UTAS, Hobart, Australia.

PUBLICATIONS Susanne RK Zajitschek, Jonathan P Evans & Robert Brooks (2006) Independent effects of familiarity and mating preferences for ornamental traits on mating decisions in guppies. Behavioral Ecology 17:911-916   Felix Zajitschek, John Hunt, Susanne R.K. Zajitschek, Michael D. Jennions & Robert Brooks (2007) No intra-locus sexual conflict over reproductive fitness or ageing in field crickets. PloS ONE 2(1), e155   Jonathan P. Evans, Robert Brooks, Susanne R.K. Zajitschek & Simon C. Griffith (2008) No evidence that genetic relatedness of mates influences competitive fertilization success in guppies. Submitted.   Susanne RK Zajitschek & Robert Brooks. Distinguishing the effects of familiarity, relatedness and colour pattern rarity on attractiveness and measuring their effects on sexual selection in guppies (Poecilia reticulata). Submitted.

Susanne RK Zajitschek, Anna Lindholm, Jonathan P Evans & Robert Brooks. Experimental evidence that high levels of inbreeding depress sperm competitiveness, but not ornamental traits.

 

Susanne RK Zajitschek & Robert Brooks. Inbreeding depression in male traits and preference for outbred males in Poecilia reticulata.

 

Susanne RK Zajitschek, Felix Zajitschek & Robert Brooks. Demographic costs of inbreeding revealed by sex-specific genetic rescue effects.

 

Felix Zajitschek, Russell Bonduriansky, Susanne RK Zajitschek, Robert Brooks. Age-dependent patterns of reproduction and mortality of male and female Black Field crickets, Teleogryllus commodus, in field enclosures.

 

Mylene Mariette, Susanne RK Zajitschek & Robert Brooks. The effects of population size on the avoidance of familiar mates in the guppy, Poecilia reticulata.

 

Beate Nürnberger, Felix Zajitschek, Susanne R.K. Zajitschek, Gyóngyver Mara. Differential temperature adaptation in tadpoles of the hybrdising toads Bombina bombina and B. variegata.

EVOLUTIONARY ECOLOGY OF SEXUAL REPRODUCTION RESEARCH GROUP

Evolution and Ecology Research centre 

Felix Zajitschek

Beate Nürnberger, LMU

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Tel: +61 (02) 9385 2124
Email: susanne.zajitschekstudent.unsw.edu.au