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South, Sandra H.
Alternative names
Publications (8 of 8) Show all publications
South, S. H., House, C. M., Moore, A. J., Simpson, S. J. & Hunt, J. (2011). Male Cockroaches Prefer a High Carbohydrate Diet that Makes them More Attractive to Females: implications for the study of condition dependence. Evolution, 65(6), 1594-1606
Open this publication in new window or tab >>Male Cockroaches Prefer a High Carbohydrate Diet that Makes them More Attractive to Females: implications for the study of condition dependence
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2011 (English)In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 65, no 6, p. 1594-1606Article in journal (Refereed) Published
Abstract [en]

Sexual selection is a major force driving the evolution of elaborate male sexual traits. Handicap models of sexual selection predict that male sexual traits should covary positively with condition, making them reliable indicators of male quality. However, most studies have either manipulated condition through varying diet quantity and/or caloric content without knowledge of specific nutrient effects or have correlated proxies of condition with sexual trait expression. We used nutritional geometry to quantify protein and carbohydrate intake by male cockroaches, Nauphoeta cinerea, and related this to sex pheromone expression, attractiveness, and dominance status. We found that carbohydrate, but not protein, intake is related to male sex pheromone expression and attractiveness but not dominance status. Additionally, we related two condition proxies (weight gain and lipid reserves) to protein and carbohydrate acquisition. Weight gain increased with the intake of both nutrients, whereas lipid reserves only increased with carbohydrate intake. Importantly, lipid accumulation was not as responsive to carbohydrate intake as attractiveness and thus was a less-accurate condition proxy. Moreover, males preferentially consumed high carbohydrate diets with little regard for protein content suggesting that they actively increase their carbohydrate intake thereby maximizing their reproductive fitness by being attractive.

Keywords
diet choice, nauphoeta cinerea, nutritional geometry, sex pheromone, sexual selection
National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-155253 (URN)10.1111/j.1558-5646.2011.01233.x (DOI)000291270300007 ()
Available from: 2011-06-20 Created: 2011-06-20 Last updated: 2017-12-11Bibliographically approved
South, S. (2011). The Evolution of Sexually Homologous Ornaments: Selection via Male Mate Choice Coinciding with Male-Male Competition in a Neotropical Mosquito. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>The Evolution of Sexually Homologous Ornaments: Selection via Male Mate Choice Coinciding with Male-Male Competition in a Neotropical Mosquito
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The evolution of elaborate male ornaments via sexual selection is well-understood while the selective pressures acting on female ornaments remains unresolved. Female ornaments in species with strong sexual selection on the male homologue of the ornament were originally thought to result from an intersexual genetic correlation. My thesis explores the evolution of ornaments in females due to direct selection by developing theoretical models and examining the biology of a neotropical mosquito (Sabethes cyaneus) with sexually homologous ornaments coinciding with male-male competition.

I began by exploring the morphology of the ornaments in both sexes of S. cyaneus. Sexual dimorphism in the size and shape of the ornaments was slight and both male and female ornaments showed classic hallmarks of sexually selected traits. I then tested for direct selection on S. cyaneus male and female ornaments via mutual mate choice. I found evidence of male, but surprisingly not female, preferences for ornaments.

I then further considered the evolution of male mate choice in polygynous species. First, I investigated whether male investment in courtship by S. cyaneus may result in a lower operational sex ratio and thereby reduce the costs associated with male mate choice. Male courtship did pose a significant longevity cost to male S. cyaneus. Second, I explored the possibility that a female preference for male courtship effort may contribute to the benefits of male mate choice in a series of population genetic models. The spread of a male preference gene can be driven by female preferences for male courtship when males court preferred females more.

Finally, I found that female S. cyaneus are not benefitting from signalling to increase their mating rate as they are monandrous. My thesis therefore challenges standing sexual selection theory and suggests that sexual selection on females may be more widespread than previously thought.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2011. p. 52
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 799
Keywords
sexual selection, Sabethes cyaneus, Diptera, Culicidae, mosquito, mutual ornamentation, sexual selection, mutual mate choice, male mate choice, female ornament, ecology, animal behaviour
National Category
Ecology
Research subject
Animal Ecology
Identifiers
urn:nbn:se:uu:diva-141936 (URN)978-91-554-7985-5 (ISBN)
Public defence
2011-02-25, Zootissalen, EBC, Villavägen 9, Uppsala, 09:30 (English)
Opponent
Supervisors
Note
Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 729Available from: 2011-02-03 Created: 2011-01-12 Last updated: 2011-03-21Bibliographically approved
Kolluru, G. R., Grether, G. F., Dunlop, E. & South, S. H. (2009). Food availability and parasite infection influence mating tactics in guppies (Poecilia reticulata). Behavioral Ecology, 20(1), 131-137
Open this publication in new window or tab >>Food availability and parasite infection influence mating tactics in guppies (Poecilia reticulata)
2009 (English)In: Behavioral Ecology, ISSN 1045-2249, E-ISSN 1465-7279, Vol. 20, no 1, p. 131-137Article in journal (Refereed) Published
Abstract [en]

Despite the important effects of diet and parasite infection on male reproductive behavior, few studies have simultaneously addressed their influence on intrasexual selection (male-male competition). We examined the synergistic effects of 2 naturally varying environmental factors, lifetime food intake and infection, with the monogenean parasite Gyrodactylus turnbulli on the mating tactics and foraging behavior of male guppies (Poecilia reticulata). We allowed fish to interact directly with each other during observations and found that unparasitized males won more intermale contests, courted females more frequently, and received positive responses to courtship displays more frequently than males that had been infected. Infected males devoted more time to foraging and less time to courtship and competition than uninfected males, suggesting that they were energetically limited and could not increase reproductive effort despite their reduced expected lifespan. This interpretation was supported by the observation that greater food intake ameliorated the negative effects of parasite infection on courtship effort. Our results have bearing on how natural variation in food availability and parasite prevalence influence geographic variation in reproductive behavior.

National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-135152 (URN)10.1093/beheco/arn124 (DOI)000262152300017 ()
Available from: 2010-12-06 Created: 2010-12-05 Last updated: 2017-12-12Bibliographically approved
South, S. H., Steiner, D. & Arnqvist, G. (2009). Male mating costs in a polygynous mosquito with ornaments expressed in both sexes. Proceedings of the Royal Society of London. Biological Sciences, 276(1673), 3671-3678
Open this publication in new window or tab >>Male mating costs in a polygynous mosquito with ornaments expressed in both sexes
2009 (English)In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 276, no 1673, p. 3671-3678Article in journal (Refereed) Published
Abstract [en]

Male mate choice in species with conventional sex roles is difficult to explain and has, therefore, been the focus of many recent theoretical models. These models have focused on variance in female quality and, to a lesser extent, male investments/costs associated with mating. In this study, we investigate the costs of courtship and copulation in the polygynous mosquito Sabethes cyaneus. In this species, both males and females possess elaborate ornaments. Previous studies suggest that the most likely explanation for the presence of these ornaments is mutual mate choice. Thus, this system provides an excellent model for exploring the evolution of mutual mate choice in polygynous species. We disentangle the costs of courtship and copulation by monitoring male survival in three groups of males: housed alone (group 1); able only to court females (group 2); or able to court and copulate with females (group 3). We show that males incur a cost of courtship and copulation and that courtship intensity is negatively related to male longevity. Our results suggest that courtship and copulation carry additive costs to males. We discuss the implications of these results in the context of current mutual mate choice theory and suggest that courtship costs may be an unappreciated key factor in the evolution of male mate choice.

Keywords
Culicidae, Diptera, mutual mate choice, sex roles, sexual selection
National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-127511 (URN)10.1098/rspb.2009.0991 (DOI)000270172200013 ()
Available from: 2010-12-06 Created: 2010-07-13 Last updated: 2017-12-12Bibliographically approved
Archer, C. R., Royle, N., South, S. H., Selman, C. & Hunt, J. (2009). Nutritional Geometry Provides Food for Thought. The journals of gerontology. Series A, Biological sciences and medical sciences, 64A(9), 956-959
Open this publication in new window or tab >>Nutritional Geometry Provides Food for Thought
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2009 (English)In: The journals of gerontology. Series A, Biological sciences and medical sciences, ISSN 1079-5006, E-ISSN 1758-535X, Vol. 64A, no 9, p. 956-959Article in journal (Refereed) Published
Abstract [en]

Dietary Restriction extends lifespan in a diverse range of animals, but this often comes at a cost to reproduction. While a number of molecular pathways integral to these relationships have been characterised, we still do not fully understand whether restriction of specific nutrients or calories is responsible. Two recent studies on insects have offered novel insights into this longstanding issue via the application of Nutritional Geometry. This technique promises to significantly advance our understanding of how nutrition influences reproduction and longevity.

Keywords
Nutritional geometry, Reproduction, Longevity
National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-135150 (URN)10.1093/gerona/glp069 (DOI)000269343000004 ()
Available from: 2010-12-06 Created: 2010-12-05 Last updated: 2017-12-12Bibliographically approved
South, S. H. & Arnqvist, G. (2008). Evidence of monandry in a mosquito (Sabethes cyaneus) with elaborate ornaments in both sexes. Journal of insect behavior, 21(6), 451-459
Open this publication in new window or tab >>Evidence of monandry in a mosquito (Sabethes cyaneus) with elaborate ornaments in both sexes
2008 (English)In: Journal of insect behavior, ISSN 0892-7553, E-ISSN 1572-8889, Vol. 21, no 6, p. 451-459Article in journal (Refereed) Published
Abstract [en]

Despite the benefits of multiple mating to females many mosquitoes appear to be monandrous. Members of the mosquito tribe Sabethini are unique among the mosquitoes for they possess iridescent scales and elaborate ornaments in both sexes. Additionally, this tribe boasts the only reported cases of courtship display within the mosquitoes. Due to these singular traits and behaviors, we predicted that members of this tribe have a different mating system with relatively high female mating rate. We tested this prediction in the ornamented mosquito Sabethes cyaneus. Contrary to our prediction, however, females were monandrous throughout their lifetime and multiple gonotrophic cycles. We discuss the possible implications of monandry on the evolution of sexually homologous ornaments, with particular consideration of mutual mate choice.

National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-107854 (URN)10.1007/s10905-008-9137-0 (DOI)000259733300001 ()
Available from: 2009-08-31 Created: 2009-08-31 Last updated: 2017-12-13Bibliographically approved
Kolluru, G. R., Grether, G. F., South, S. H., Dunlop, E., Cardinali, A., Liu, L. & Carapiet, A. (2006). The effects of carotenoid and food availability on resistance to a naturally occurring parasite (Gyrodactylus turnbulli) in guppies (Poecilia reticulata). Biological Journal of the Linnean Society, 89(2), 301-309
Open this publication in new window or tab >>The effects of carotenoid and food availability on resistance to a naturally occurring parasite (Gyrodactylus turnbulli) in guppies (Poecilia reticulata)
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2006 (English)In: Biological Journal of the Linnean Society, ISSN 0024-4066, E-ISSN 1095-8312, Vol. 89, no 2, p. 301-309Article in journal (Refereed) Published
Abstract [en]

Dietary carotenoids have been shown to confer immunological benefits to some species of animals in which males also use these pigments to attract mates. Thus, the potential exists for an allocation trade-off between the sexual and immunological functions of carotenoids. Food availability may also influence immune system function. The present study examined the effects of carotenoid and food availability on the resistance of male guppies (Poecilia reticulata Peters) from four wild populations to the parasite Gyrodactylus turnbulli Harris. Intermediate levels of carotenoid ingestion resulted in the lowest parasite loads, which suggests that carotenoids strengthen parasite resistance at low levels but either benefit parasites or suppress host immunity at high levels. Males raised on the high-food level initially had fewer parasites, suggesting heightened innate immunity relative to males raised on the low-food level. Over the course of the experiment, however, the high-food males supported higher parasite population growth rates than the low-food males. The results obtained emphasize the importance of evaluating the effects of diet on multiple aspects of immune system function, and caution against assuming that positive effects of carotenoids on immunity in one context will automatically translate to other contexts.

Keywords
geographical variation, parasite load, parasite resistance, susceptibility, trade-off
National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-135154 (URN)10.1111/j.1095-8312.2006.00675.x (DOI)000240557300005 ()
Available from: 2010-12-06 Created: 2010-12-05 Last updated: 2017-12-12Bibliographically approved
South, S., Arnqvist, G. & Servedio, M.Female preference for male courtship effort drives the evolution of male mate choice.
Open this publication in new window or tab >>Female preference for male courtship effort drives the evolution of male mate choice
(English)Manuscript (preprint) (Other academic)
Abstract [en]

The evolution of male mate choice is constrained by costs of choice in species with a male-biasedoperational sex ratio. Previous theoretical studies have shown that significant male benefits ofmale choice are required, e.g., by mating with more fecund females, in order for these costs to beoffset and the male preference to spread. We consider the possibility that another type of effectmay favour the evolution of male mate choice by exploring a series of population genetic models.We find that a male mating preference can spread when males court preferred females more andfemales prefer, and thus are more likely to mate with, males who court more. Further, viability orfecundity selection on the preferred female trait is a much more powerful determinant of the fateof the female trait than is the presence of the male preference. We confirm that indirect selectionon the male preference due to linkage disequilibrium between the female trait and malepreference alleles can affect the evolution of the male trait, however, these effects are slight incomparison to direct selection on the male trait.

National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-141925 (URN)
Available from: 2011-01-12 Created: 2011-01-12 Last updated: 2011-03-11
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