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Amcoff, Mirjam
Publications (8 of 8) Show all publications
Amcoff, M. & Kolm, N. (2014). A test of sensory exploitation in the swordtail characin (Corynopoma riisei) based on colour matchingbetween female prey and a male ornament. Environmental Biology of Fishes, 97(3), 247-254
Open this publication in new window or tab >>A test of sensory exploitation in the swordtail characin (Corynopoma riisei) based on colour matchingbetween female prey and a male ornament
2014 (English)In: Environmental Biology of Fishes, ISSN 0378-1909, E-ISSN 1573-5133, Vol. 97, no 3, p. 247-254Article in journal (Refereed) Published
Abstract [en]

The sensory exploitation hypothesis states that pre-existing biases in female sensory systems may generate strong selection on male signals to match such biases. As environmental conditions differ between populations, sexual preferences resulting from natural selection are expected to vary as well. The swordtail characin (Corynopoma riisei) is a species in which males carry a flag-like ornament growing from the operculum that has been proposed to function as a prey mimic to attract females. Here, we investigated if female plasticity in feeding preferences is associated with plasticity in preference for an artificial male ornament in this species. Females were trained for 10 days by offering them differently coloured food items and were then tested for changes in preferences for differently coloured artificial male ornaments according to foraging experience. We found a rapid and pronounced change in female preference for the colouration of the artificial ornament according to food training. Thus our results support the possibility that sensory exploitation may act as a driving force for female preferences for male ornaments in this species.

National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-215829 (URN)10.1007/s10641-013-0147-1 (DOI)000330350400003 ()
Available from: 2014-01-17 Created: 2014-01-17 Last updated: 2017-12-06Bibliographically approved
Amcoff, M., Hallsson, L. R., Winberg, S. & Kolm, N. (2014). Male Courtship Pheromones Affect Female Behaviour in the Swordtail Characin ( Corynopoma riisei). Ethology, 120(5), 463-470
Open this publication in new window or tab >>Male Courtship Pheromones Affect Female Behaviour in the Swordtail Characin ( Corynopoma riisei)
2014 (English)In: Ethology, ISSN 0179-1613, E-ISSN 1439-0310, Vol. 120, no 5, p. 463-470Article in journal (Refereed) Published
Abstract [en]

Pheromones constitute an important cue used by both males and females during courtship. Here, we investigate the effect of male pheromones on female behaviour in the swordtail characin (Corynopoma riisei), a species of fish where males have a caudal pheromone gland which has been suggested to affect female behaviour during courtship. We subjected female C.riisei to male courtship pheromones and investigated the effect on both female behaviour and brain serotonergic activity levels compared to a control group. While no difference in serotonergic activity was found, the pheromone-treated females showed lower stress levels compared to the control group. Furthermore, pheromone-treated females increased locomotor activity over time, while a decrease in locomotor activity was observed in the control group. These results suggest that the male courtship pheromones may serve to reduce female stress and increase female activity, possibly to aid males in gaining access to females and facilitating sperm transfer.

Keywords
courtship, olfactory cues, pheromones, serotonin, stress
National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-224320 (URN)10.1111/eth.12217 (DOI)000333696100004 ()
Available from: 2014-05-19 Created: 2014-05-09 Last updated: 2017-12-05Bibliographically approved
Amcoff, M. & Kolm, N. (2013). Does female feeding motivation affect the response to a food-mimicking male ornament in the swordtail characin Corynopoma riisei?. Journal of Fish Biology, 83(2), 343-354
Open this publication in new window or tab >>Does female feeding motivation affect the response to a food-mimicking male ornament in the swordtail characin Corynopoma riisei?
2013 (English)In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 83, no 2, p. 343-354Article in journal (Refereed) Published
Abstract [en]

Female response to various aspects of male trait morphology and the effect of female feeding motivation were investigated in the swordtail characin Corynopoma riisei, a species where males are equipped with a flag-like food-mimicking ornament that grows from the operculum. Unfed females responded more strongly to the male ornament and showed a stronger preference for larger ornaments than did fed females. Females were shown not to discriminate between artificial male ornaments of either undamaged or damaged shape.

Keywords
diet, mate preference, plasticity, sensory exploitation, signalling
National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-206572 (URN)10.1111/jfb.12175 (DOI)000322547900007 ()
Available from: 2013-09-02 Created: 2013-09-02 Last updated: 2017-12-06Bibliographically approved
Amcoff, M., Gonzalez-Voyer, A. & Kolm, N. (2013). Evolution of egg dummies in Tanganyikan cichlid fishes: the roles of parental care and sexual selection. Journal of Evolutionary Biology, 26(11), 2369-2382
Open this publication in new window or tab >>Evolution of egg dummies in Tanganyikan cichlid fishes: the roles of parental care and sexual selection
2013 (English)In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 26, no 11, p. 2369-2382Article, review/survey (Refereed) Published
Abstract [en]

Sexual selection has been suggested to be an important driver of speciation in cichlid fishes of the Great Lakes of Africa, and the presence of male egg dummies is proposed to have played a key role. Here, we investigate how mouthbrooding and egg dummies have evolved in Tanganyikan cichlids, the lineage which seeded the other African radiations, with a special emphasis on the egg dummies. Using modern phylogenetic comparative analyses and a phylogeny including 86% of the 200 described species, we provide formal evidence demonstrating correlated evolution between mouthbrooding and egg dummies in Tanganyikan cichlids. These results concur with existing evidence, suggesting that egg dummies have evolved through sensory exploitation. We also demonstrate that there is a strong evolutionary correlation between the presence of egg dummies and both pre- and post-copulatory sexual selection. Moreover, egg dummy evolution was contingent on the intensity of pre- and post-copulatory sexual selection in Tanganyikan cichlids. In sum, our results provide evidence supporting the hypothesis of egg dummies evolving through sensory exploitation and highlight the role of sexual selection in favouring the evolution and maintenance of this trait.

Keywords
BayesTraits, egg dummies, phenotypic evolution, sexual selection, signal evolution, sperm competition
National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-211127 (URN)10.1111/jeb.12231 (DOI)000325983400008 ()
Available from: 2013-11-21 Created: 2013-11-20 Last updated: 2017-12-06Bibliographically approved
Amcoff, M. (2013). Fishing for Females: Sensory Exploitation in the Swordtail Characin. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Fishing for Females: Sensory Exploitation in the Swordtail Characin
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Mate choice plays an important role in sexual selection and speciation. The evolution of mate choice is intriguing in cases where choosy individuals gain little except for genetic material from the mate and where the trait used as a criterion for the choice is costly to its bearer. The sensory exploitation hypothesis is an interesting idea that applies to such cases because it suggests that sexual preferences may arise as side-effects of preferences that are under selection in other contexts. The role of mate choice in speciation is strong but is debated because the reasons for population divergence in mate preferences and sexual traits are sometimes hard to explain. Also in this context sensory exploitation offers a potential explanation in that a link between natural and sexual selection may result in divergence in sexual selection whenever populations differ in natural selection.

In this thesis, I test several aspects of this hypothesis in a species of fish, the swordtail characin (Corynopoma riisei). In this species males display a flag-like ornament that grows from the operculum. Because females respond to this ornament by biting at it, it has been proposed to act as a food-mimic. By manipulating female food type and quantity, and testing the resulting female preference for the male ornament, I find support for the theory that the preference has evolved through sensory exploitation and that females indeed appear to relate the ornament to a food item. Furthermore, I show that sensory exploitation can lead to morphological divergence among natural populations in this species. Apart from the flag-ornament, other courtship signals are also investigated. The results show that the relative importance of different signals may vary depending on receiver motivation. This suggests that various aspects of both male courtship signals and the conditions during which they are being signalled should be considered to gain a full understanding of mate choice and its role in sexual selection and speciation.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2013. p. 43
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1076
Keywords
Sexual selection, Mate choice, Courtship, Sensory bias, Plasticity, Corynopoma riisei, Mulitiple signalling
National Category
Evolutionary Biology Zoology
Research subject
Biology with specialization in Animal Ecology
Identifiers
urn:nbn:se:uu:diva-207334 (URN)978-91-554-8758-4 (ISBN)
Public defence
2013-10-31, Ekmansalen, Norbyvägen 14, Uppsala, 09:00 (English)
Opponent
Supervisors
Available from: 2013-10-09 Created: 2013-09-12 Last updated: 2014-01-23
Amcoff, M., Lindqvist, C. & Kolm, N. (2013). Sensory exploitation and plasticity in female mate choice in the swordtail characin. Animal Behaviour, 85(5), 891-898
Open this publication in new window or tab >>Sensory exploitation and plasticity in female mate choice in the swordtail characin
2013 (English)In: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 85, no 5, p. 891-898Article in journal (Refereed) Published
Abstract [en]

Despite extensive research in the field of sexual selection, the evolutionary origin and maintenance of preferences for sexual ornaments are still debated. Recent studies have pointed out that plasticity in mate choice might be more common than previously thought, but little is still known about the factors that affect such plasticity. The swordtail characin, Corynopoma riisei, is a tropical fish species in which males use a food-mimicking ornament to attract females. We tested whether ecological factors, more specifically prior foraging experience, can affect female preference for male ornaments. For this, we habituated females on a diet consisting of either red-coloured food or standard-coloured green food items and then we tested whether female preferences for artificially red-coloured male ornaments matched their previous foraging experience. We found a strong effect of food treatment: females trained on red food showed a stronger response to males with red-coloured ornaments than females trained on green food. Our results show that ecological variation can generate divergence of female preferences for male ornaments and that the response in preference to environmental change can be rapid if the bias is partly learnt.

Keywords
Corynopoma riisei, diet, mate choice, sensory exploitation, sexual selection, swordtail characin
National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-203305 (URN)10.1016/j.anbehav.2013.02.001 (DOI)000319332000004 ()
Available from: 2013-07-08 Created: 2013-07-08 Last updated: 2017-12-06Bibliographically approved
Kolm, N., Amcoff, M., Mann, R. P. & Arnqvist, G. (2012). Diversification of a Food-Mimicking Male Ornament via Sensory Drive. Current Biology, 22(15), 1440-1443
Open this publication in new window or tab >>Diversification of a Food-Mimicking Male Ornament via Sensory Drive
2012 (English)In: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 22, no 15, p. 1440-1443Article in journal (Refereed) Published
Abstract [en]

The evolutionary divergence of sexual signals is often important during the formation of new animal species, but our understanding of the origin of signal diversity is limited [1, 2]. Sensory drive, the optimization of communication signal efficiency through matching to the local environment, has been highlighted as a potential promoter of diversification and speciation [3]. The swordtail characin (Corynopoma riisei) is a tropical fish in which males display a flag-like ornament that elicits female foraging behavior during courtship. We show that the shape of the male ornament covaries with female diet across natural populations. More specifically, natural populations in which the female diet is more dominated by ants exhibit male ornaments more similar to the shape of an ant. Feeding experiments confirm that females habituated to a diet of ants prefer to bite at male ornaments from populations with a diet more dominated by ants. Our results show that the male ornament functions as a "fishing lure" that is diversifying in shape to match local variation in female search images employed during foraging. This direct link between variation in female feeding ecology and the evolutionary diversification of male sexual ornaments suggests that sensory drive may be a common engine of signal divergence.

National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-181121 (URN)10.1016/j.cub.2012.05.050 (DOI)000307415000026 ()
Available from: 2012-09-19 Created: 2012-09-17 Last updated: 2017-12-07Bibliographically approved
Amcoff, M., Arnqvist, G. & Kolm, N. (2009). Courtship signalling with a labile bilateral signal: males show their best side. Behavioral Ecology and Sociobiology, 63(12), 1717-1725
Open this publication in new window or tab >>Courtship signalling with a labile bilateral signal: males show their best side
2009 (English)In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 63, no 12, p. 1717-1725Article in journal (Refereed) Published
Abstract [en]

Asymmetries in courtship signals can result from both developmental instability during ontogeny and from temporary or permanent damage following mating, fighting, or interactions with predators. These two types of asymmetries, which can be divided into fluctuating asymmetry (FA) and damage asymmetry (DA), have both been suggested to play an important role in mate choice as potential honest indicators of phenotypic and/or genetic quality, while at the same time, DA may affect ornament asymmetry in a random manner. Interestingly, despite the massive research effort that has been devoted to the study of asymmetry during the past decades, very little is known about how an individual's behaviour relates to asymmetry. Here, we measure and characterise asymmetry in morphological courtship signals in Corynopoma riisei, a fish where males carry elaborate paddle-like appendices on each side of the body that they display in front of females during courtship. Moreover, we investigate whether male courtship display, employing this bilateral morphological trait, reflects trait asymmetry. Finally, we assess whether males respond to phenotypic manipulations of DA with corresponding changes in courtship behaviour. We show that male display behaviour is asymmetric in a manner that reflects asymmetry of their morphological courtship trait and that male display behaviour responds to manipulations of asymmetry of these paddles. Our results thus suggest that males preferentially use their best side and, hence, that males respond adaptively to temporary changes in signal trait asymmetry.

Keywords
Sexual signalling, Sexual selection, Lateralization, Mate choice, Sensory bias, Indicator, Self-awareness
National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-127482 (URN)10.1007/s00265-009-0785-7 (DOI)000270684200003 ()
Available from: 2010-07-15 Created: 2010-07-13 Last updated: 2017-12-12Bibliographically approved
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