| 1. |
- Dijkstra, Peter D., et al.
(author)
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Divergent hormonal responses to social competition in closely related species of haplochromine cichlid fish
- 2012
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In: Hormones and Behavior. - : Elsevier BV. - 1095-6867 .- 0018-506X. ; 61:4, s. 518-526
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Journal article (peer-reviewed)abstract
- The diverse cichlid species flocks of the East African lakes provide a classical example of adaptive radiation. Territorial aggression is thought to influence the evolution of phenotypic diversity in this system. Most vertebrates mount hormonal (androgen, glucocorticoid) responses to a territorial challenge. These hormones, in turn, influence behavior and multiple aspects of physiology and morphology. Examining variation in competition-induced hormone secretion patterns is thus fundamental to an understanding of the mechanisms of phenotypic diversification. We test here the hypothesis that diversification in male aggression has been accompanied by differentiation in steroid hormone levels. We studied two pairs of sibling species from Lake Victoria belonging to the genera Pundamilia and Mbipia. The two genera are ecologically differentiated, while sibling species pairs differ mainly in male color patterns. We found that aggression directed toward conspecific males varied between species and across genera: Pundamilia nyererei males were more aggressive than Pundamilia pundamilia males, and Mbipia mbipi males were more aggressive than Mbipia lutea males. Males of both genera exhibited comparable attack rates during acute exposure to a novel conspecific intruder, while Mbipia males were more aggressive than Pundamilia males during continuous exposure to a conspecific rival, consistent with the genus difference in feeding ecology. Variation in aggressiveness between genera, but not between sibling species, was reflected in androgen levels. We further found that M. mbipi displayed lower levels of cortisol than M. lutea. Our results suggest that concerted divergence in hormones and behavior might play an important role in the rapid speciation of cichlid fishes. (C) 2012 Elsevier Inc. All rights reserved.
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| 2. |
- Estramil, Natalia, et al.
(author)
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Cichlids respond to conspecific sounds but females exhibit no phonotaxis without the presence of live males
- 2014
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In: Ecology of Freshwater Fish. - : Wiley. - 0906-6691. ; 23:3, s. 305-312
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Journal article (peer-reviewed)abstract
- Many fish species are able to produce sounds, which are often associated with courtship. In an earlier study, we showed for the Lake Victoria cichlid Pundamilia nyererei that females prefer to associate with a male with sound over a male without sound. As a follow-up to this earlier finding, we here investigated whether playback of conspecific sounds is sufficient to attract females in the absence of a conspecific male. However, we did not find a phonotactic response for conspecific sounds in the absence of live males, using the same playback procedure as in our previous study. An additional playback test showed that both males and females discriminated between conspecific sounds and bursts of white noise. This suggests that the sounds may be recognised but that they seem only effective as attractant in the presence of visual and/or olfactory cues. These findings underline the multimodal complexity of fish communication and courtship and call for a more integrated study of the different modalities in future studies.
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| 3. |
- Hollander, Johan, et al.
(author)
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Dispersal and phenotypic plasticity
- 2014
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In: Animal movement across scales. - : Oxford University Press. - 9780199677184 ; , s. 110-125
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Book chapter (peer-reviewed)
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| 4. |
- Lachlan, Robert F., et al.
(author)
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The Progressive Loss of Syntactical Structure in Bird Song along an Island Colonization Chain
- 2013
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In: Current Biology. - : Elsevier BV. - 1879-0445 .- 0960-9822. ; 23:19, s. 1896-1901
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Journal article (peer-reviewed)abstract
- Cultural transmission can increase the flexibility of behavior, such as bird song. Nevertheless, this flexibility often appears to be constrained, sometimes by preferences for learning certain traits over others, a phenomenon known as "biased" learning or transmission [1]. The sequential colonization of the Atlantic Islands by the chaffinch (Fringilla coelebs) [2] provides a unique model system in which to investigate how the variability of a cultural trait has evolved. We used novel computational methods to analyze chaffinch song from twelve island and continental populations and to infer patterns of evolution in song structure. We found that variability of the subunits within songs ("syllables") differed moderately between populations but was not predicted by whether the population was continental or not. In contrast, we found that the sequencing of syllables within songs ("syntax") was less structured in island than continental populations and in fact decreased significantly after each colonization. Syntactical structure was very clear in the mainland European populations but was almost entirely absent in the most recently colonized island, Gran Canaria. Our results suggest that colonization leads to the progressive loss of a species-specific feature of song, syntactical structure.
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| 5. |
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| 6. |
- Svensson, Erik, et al.
(author)
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Sex differences in developmental plasticity and canalization shape population divergence in mate preferences.
- 2014
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In: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954. ; 281:1797
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Journal article (peer-reviewed)abstract
- Sexual selection of high-quality mates can conflict with species recognition if traits that govern intraspecific mate preferences also influence interspecific recognition. This conflict might be resolved by developmental plasticity and learned mate preferences, which could drive preference divergence in populations that differ in local species composition. We integrate field and laboratory experiments on two calopterygid damselfly species with population genetic data to investigate how sex differences in developmental plasticity affect population divergence in the face of gene flow. Whereas male species recognition is fixed at emergence, females instead learn to recognize heterospecifics. Females are therefore more plastic in their mate preferences than males. We suggest that this results from sex differences in the balance between sexual selection for high-quality mates and selection for species recognition. As a result of these sex differences, females develop more pronounced population divergence in their mate preferences compared with males. Local ecological community context and presence of heterospecifics in combination with sex differences in plasticity and canalization therefore shape population divergence in mate preferences. As ongoing environmental change and habitat fragmentation bring formerly allopatric species into secondary contact, developmental plasticity of mate preferences in either or both sexes might facilitate coexistence and prevent local species extinction.
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| 7. |
- Verzijden, Machteld, et al.
(author)
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Effects of sensory modality on learned mate preferences in female swordtails
- 2011
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In: Animal Behaviour. - : Elsevier BV. - 1095-8282 .- 0003-3472. ; 82:3, s. 557-562
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Journal article (peer-reviewed)abstract
- Females often base their mate selection on multiple male traits. Different cues may be weighted differently in mating decisions, and play different roles such as indicating species identity or condition. The ontogeny of preferences for each cue can differ, which may offer a proximate explanation for the differential female evaluation of multimodal traits of males. We investigated whether female preferences for the multimodal male cues of Xiphophorus birchmanni swordtails are learned for traits in both olfactory and visual sensory modalities. We reared X. birchmanni females with either conspecific adults or adults of a closely related species, Xiphophorus malinche. We found that both olfactory and visual preferences were learned, and that the timing of olfactory learning was different from that of visual cues. (C) 2011 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
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| 8. |
- Verzijden, Machteld, et al.
(author)
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Immediate spectral flexibility in singing chiffchaffs during experimental exposure to highway noise
- 2010
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In: Journal of Experimental Biology. - : The Company of Biologists. - 1477-9145 .- 0022-0949. ; 213:15, s. 2575-2581
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Journal article (peer-reviewed)abstract
- Sound plays an important role in the life of many animals, including many bird species. Typically, male birds sing to defend a territory and to attract mates. Ambient noise may negatively affect the signal efficiency of their songs, which may be critical to reproductive success. Consequently, anthropogenic noise may be detrimental to individual birds and to populations in cities and along highways. Several bird species that are still common in urban areas have been shown to sing at higher frequency at locations where there is more low-frequency traffic noise. Here we show that chiffchaffs along noisy highways also sing with a higher minimum frequency than chiffchaffs nearby at a quiet riverside. Furthermore, through experimental exposure to highway noise we show that these birds are capable of making such adjustments over a very short time scale. The first 10 songs sung during the noise exposure revealed an immediate shift to higher frequencies, with a return to pre-exposure levels in recordings without noise the following day. In a transmission re-recording experiment we tested the impact of a potential measurement artifact by recording playback of the same songs repeatedly under different controlled noise conditions. We found an upward shift in the minimum frequency measurement associated with more noisy recordings of the same song, but this artifact was not of a scale that it could explain the noise-dependent spectral shifts in chiffchaffs.
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| 9. |
- Verzijden, Machteld N., et al.
(author)
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Interspecific interactions and learning variability jointly drive geographic differences in mate preferences
- 2016
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In: Evolution. - : Wiley. - 0014-3820. ; 70:8, s. 1896-1903
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Journal article (peer-reviewed)abstract
- Co-occurrence of closely related species can cause behavioral interference in mating and increase hybridization risk. Theoretically, this could lead to the evolution of more species-specific mate preferences and sexual signaling traits. Alternatively, females can learn to reject heterospecific males, to avoid male sexual interference from closely related species. Such learned mate discrimination could also affect conspecific mate preferences if females generalize from between species differences to prefer more species-specific mating signals. Female damselflies of the banded demoiselle (Calopteryx splendens) learn to reject heterospecific males of the beautiful demoiselle (C. virgo) through direct premating interactions. These two species co-occur in a geographic mosaic of sympatric and microallopatric populations. Whereas C. virgo males have fully melanized wings, male C. splendens wings are partly melanized. We show that C. splendens females in sympatry with C. virgo prefer smaller male wing patches in conspecific males after learning to reject heterospecific males. In contrast, allopatric C. splendens females with experimentally induced experience with C. virgo males did not discriminate against larger male wing patches. Wing patch size might indicate conspecific male quality in allopatry. Co-occurrence with C. virgo therefore causes females to prefer conspecific male traits that are more species specific, contributing to population divergence and geographic variation in female mate preferences.
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| 10. |
- Verzijden, Machteld N., et al.
(author)
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Male Drosophila melanogaster learn to prefer an arbitrary trait associated with female mating status
- 2015
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In: Current Zoology. - 1674-5507. ; 61:6, s. 1036-1042
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Journal article (peer-reviewed)abstract
- Although males are generally less discriminating than females when it comes to choosing a mate, they still benefit from distinguishing between mates that are receptive to courtship and those that are not, in order to avoid wasting time and energy. It is known that males of Drosophila melanogaster are able to learn to associate olfactory and gustatory cues with female receptivity, but the role of more arbitrary, visual cues in mate choice learning has been overlooked to date in this species. We therefore carried out a series of experiments to determine: 1) whether males had a baseline preference for female eye color (red versus brown), 2) if males could learn to associate an eye color cue with female receptivity, and 3) whether this association disappeared when the males were unable to use this visual cue in the dark. We found that naive males had no baseline preference for females of either eye color, but that males which were trained with sexually receptive females of a given eye color showed a preference for that color during a standard binary choice experiment. The learned cue was indeed likely to be truly visual, since the preference disappeared when the binary choice phase of the experiment was carried out in darkness. This is, to our knowledge 1) the first evidence that male D. melanogaster can use more arbitrary cues and 2) the first evidence that males use visual cues during mate choice learning. Our findings suggest that that D. melanogaster has untapped potential as a model system for mate choice learning.
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| 11. |
- Verzijden, Machteld, et al.
(author)
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Opposite effects of learning cause asymmetric mate preferences in hybridizing species
- 2012
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In: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 23:5, s. 1133-1139
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Journal article (peer-reviewed)abstract
- How do females decide which males to accept or reject as potential mates when the individuals encountered are unfamiliar and may be either heterospecifics or conspecifics? Learning often influences the development of mate preferences. Experience with particular phenotypes often positively biases preference for that phenotype. However, experience can also induce aversion. We studied the effect of short-term experience with unfamiliar conspecific, heterospecific, or hybrid males on mate preferences of females of 2 swordtail fish species with native habitats,which differ in both ecology and effective population size. After exposure to males for a week, we tested the females' preferences for male olfactory cues. Both species shifted their mate preferences, but in opposite directions. Female Xiphophorus.birchmanni, living in larger populations, increased their preference for familiar phenotypes, whereas female X. malinche, from smaller, island-like populations, showed an inverse effect of familiarity, namely a decreased preference for newly familiarized males. The pattern of opposite effects of learning on mate choice mirrors with that seen in the evolution of reinforcement of genetic preferences in continental and island populations. Diametrically opposed shifts in preference can thus arise from the same social experience, causing asymmetry in the species' conspecific mate preferences.
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| 12. |
- Verzijden, Machteld, et al.
(author)
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The effects of experience on the development of sexual behaviour of males and females of the banded demoiselle (Calopteryx splendens).
- 2014
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In: Behavioural Processes. - : Elsevier BV. - 0376-6357. ; 109:Online 2 September 2014, s. 180-189
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Journal article (peer-reviewed)abstract
- Mate preferences can vary in the direction of the preference, as well as the strength of the preference, and both direction and strength of preference are known to be plastic in many species. Preferences might have a learned component, and current and past social context may influence an individual's choosiness. In the damselfly species Calopteryx splendens, females increase the strength of their mate preferences with sexual experience. Here we show that sexually naïve females selectively respond to conspecific courtship as soon as physical contact has been established, suggesting a role for tactile cues perceived through interspecific morphological differences in secondary reproductive traits. In addition our data also shows that males and females selectively respond to the intensity of the courtship of the potential, conspecific mate, while ignoring such information in heterospecific potential mates. These results underscore that mate choice is the result of dynamic interactions between the sexes, where both current and past information are integrated. This article is part of a Special Issue entitled: Cognition in the Wild.
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| 13. |
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| 14. |
- Verzijden, Machteld, et al.
(author)
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The impact of learning on sexual selection and speciation.
- 2012
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In: Trends in Ecology & Evolution. - : Elsevier BV. - 1872-8383 .- 0169-5347. ; 27:9, s. 511-519
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Journal article (peer-reviewed)abstract
- Learning is widespread in nature, occurring in most animal taxa and in several different ecological contexts and, thus, might play a key role in evolutionary processes. Here, we review the accumulating empirical evidence for the involvement of learning in mate choice and the consequences for sexual selection and reproductive isolation. We distinguish two broad categories: learned mate preferences and learned traits under mate selection (such as bird song). We point out that the context of learning, namely how and when learning takes place, often makes a crucial difference to the predicted evolutionary outcome. Factors causing biases in learning and when one should expect the evolution of learning itself are also explored.
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