| 1. |
- Wheatcroft, David, et al.
(författare)
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Species-specific song responses emerge as a by-product of tuning to the local dialect
- 2022
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 32:23, s. 5153-5158, 5153–5158.e1–e5
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Tidskriftsartikel (refereegranskat)abstract
- Oscine birds preferentially respond to certain sounds over others from an early age, which focuses subsequent learning onto sexually relevant songs. Songs vary both across species and, due to cultural evolution, among populations of the same species. As a result, early song responses are expected to be shaped by selection both to avoid the fitness costs of cross-species learning and to promote learning of population-typical songs. These sources of selection are not mutually exclusive but can result in distinct geographic patterns of song responses in juvenile birds: if the risks of interspecific mating are the main driver of early song discrimination, then discrimination should be strongest where closely related species co-occur. In contrast, if early discrimination primarily facilitates learning local songs, then it should be tuned to songs typical of the local dialect. Here, we experimentally assess the drivers of song discrimination in nestling pied flycatchers (Ficedula hypoleuca). We first demonstrate that early discrimination against the songs of the closely related collared flycatcher (F. albicollis) is not strongly affected by co-occurrence. Second, across six European populations, we show that nestlings’ early song responses are tuned to their local song dialect and that responses to the songs of collared flycatchers are similarly weak as to those of other conspecific dialects. Taken together, these findings provide clear experimental support for the hypothesis that cultural evolution, in conjunction with associated learning predispositions, drives the emergence of pre-mating reproductive barriers.
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| 2. |
- Bliard, Louis, et al.
(författare)
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The role of introductory alarm calls for song discrimination in Ficedula flycatchers
- 2021
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Ingår i: Animal Behaviour. - : Elsevier. - 0003-3472 .- 1095-8282. ; 177, s. 241-251
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Tidskriftsartikel (refereegranskat)abstract
- Assortative mating depends on species distinctiveness in mating traits and preferences, which can be challenging to maintain when traits and/or preferences are learned. This is because learning may cause individuals to copy heterospecific signals. Juvenile songbirds possess innate sensory biases favouring them to learn and to prefer conspecific songs, but the effectiveness of these biases relies on consistent and sufficient differences between the songs produced by different species. However, mating signals, including learned songs, sometimes converge in sympatry, and the species-specific cues that individuals use to shape their preferences are often unknown. In Ficedula flycatchers, a stereotyped and highly species-specific alarm call is often incorporated as the first syllable of their songs. However, where the two species co-occur, pied flycatchers, Ficedula hypoleuca, learn to incorporate the introductory calls of the closely related collared flycatcher, Ficedula albicollis, into their songs. In this study, we investigated the role of introductory alarm calls for song discrimination in collared flycatchers, using playback experiments of both manipulated and unmanipulated songs on adults and nestlings within the hybrid zone of Oland, Sweden. We predicted that the introductory alarm call would be sufficient to trigger song responses, such that adults and nestlings would respond similarly to song phrases including the call, whether it is followed by conspecific or heterospecific notes. Our results provide evidence that the introductory alarm call is sufficient to trigger song discrimination in nestlings, but not in adult males, potentially due to their greater experience with songs and, therefore, subtler discrimination. Altogether, this study highlights the often-overlooked importance of calls within or associated with songs.
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| 3. |
- Boussard, Annika, et al.
(författare)
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No Sex-Specific Effects of Artificial Selection for Relative Telencephalon Size during Detour Learning and Spatial Discrimination in Guppies (Poecilia reticulata)
- 2023
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Ingår i: Fishes. - 2410-3888. ; 8:11
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Tidskriftsartikel (refereegranskat)abstract
- Over recent decades, substantial research has focused on fish cognitive evolution to increase our understanding of the evolution of the enormous diversity of cognitive abilities that exists in fishes. One important but understudied aspect of cognitive evolution is sexual dimorphism in cognitive abilities. Sex-specific variation in brain region morphology has been proposed to be an important mechanism in this context. However, it is also common to find sex-specific variation in behavior and cognition without associated differences in brain morphology among the sexes. The telencephalon is the major cognitive center in the vertebrate brain and variation in telencephalon size has been associated with variation in cognition. Here, we utilize recently developed guppy artificial selection lines with ca. 10% differences in relative telencephalon size to investigate whether similar responses to selection of the size of this region may affect cognitive abilities differently in males and females. To that end, we compared two ecologically relevant aspects of cognition, detour learning and binary spatial discrimination. We tested the significance of the interaction between telencephalon size and sex, and we found no sex-specific effects of evolutionary increases in telencephalon size in the cognitive abilities tested. This study indicates that no clear cognitive sex-specific effects occur in response to rapid selection of telencephalon size. We suggest that future research on sexual dimorphism in cognitive abilities in fish could use various cognitive tests and examine telencephalic sub-regions to gain a more comprehensive understanding of their evolution.
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| 4. |
- Chase, Madeline, et al.
(författare)
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The combination of HiFi and HiC sequencing technologies enables the investigation of structural variants in speciation of Ficedula flycatchers
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Structural variants, typically defined as mutations affecting more than 50bp, have been shown to encompass a significant portion of the genome and can have large phenotypic effects. Additionally, increasing empirical evidence demonstrates that structural variants may play a substantial role in speciation, which could previously have been overlooked because of difficulties in identifying them with short-read data. However, with the increased availability of long-read sequencing technology we are now equipped better than ever to address this limitation and study the contribution of different types of structural variants to genetic variation within and genetic differentiation between closely related species. Here, we follow this approach and combine PacBio HiFi and HiC sequencing for two closely related passerine birds, the collared flycatcher and the pied flycatcher. This enables us to generate a chromosome-level genome assembly for both species, and identify structural variants between the two species. Based on population-level HiFi sequencing for both species, we then investigate patterns of single nucleotide diversity and differentiation within and between species and their association with different types of structural variation. We find widespread structural variation between the two species, where both the sex chromosomes show a disproportionate number of structural variants, which may help explain the suspected role of the Z-chromosome in contributing to genetic incompatibilities. We also find that genomic differentiation peaks are enriched in both translocations and inversions, which supports a mechanistic role of structural variation in population differentiation and speciation.
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| 5. |
- Dutour, Mylene, et al.
(författare)
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Great tit responses to the calls of an unfamiliar species suggest conserved perception of call ordering
- 2020
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Ingår i: Behavioral Ecology and Sociobiology. - : SPRINGER. - 0340-5443 .- 1432-0762. ; 74:3
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Tidskriftsartikel (refereegranskat)abstract
- Many species of birds produce distinct calls when mobbing predators. These calls often recruit nearby conspecifics and heterospecifics to help drive the predators away. In some species, such as members of the family Paridae, mobbing calls are composed of multiple elements that seem to follow a characteristic order. Previous work in parids demonstrated that note ordering influences both the responses of conspecifics and some other co-occurring Paridae species. Cross-species sensitivity to note ordering could result from individuals' learning to associate individual heterospecific calls with threats or, rather, because the typical note orderings are shared across species. Here, we test these hypotheses by assessing the responses of European great tits (Parus major) to the naturally and artificially ordered calls of black-capped chickadees (Poecile atricapillus), a North American species. In response to the naturally ordered mobbing calls of chickadees, we found that great tits exhibit vigilance and rapidly approach the sound source, behaviors that were indistinguishable to those expressed in response to conspecific calls. If learned associations are necessary for sensitivity to note ordering, then a key prediction is that great tit responses to naturally ordered and artificially reversed chickadee calls should be similar (and weak). In contrast to this prediction, we found that great tits were less vigilant, but approach the sound source in response to artificially reversed chickadee calls. These findings suggest that perception of note ordering patterns is conserved. However, they are also in agreement with a "perception bias" hypothesis: that the first notes of the call mask the notes that follow them, preventing the receiver from perceiving the second part of the call. Although we provide evidence against perception bias, further research is needed to convincingly disentangle these two hypotheses.
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| 6. |
- Gallego-Abenza, Mario, et al.
(författare)
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Experience modulates an insect's response to anthropogenic noise
- 2020
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Ingår i: Behavioral Ecology. - : OXFORD UNIV PRESS INC. - 1045-2249 .- 1465-7279. ; 31:1, s. 90-96
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Tidskriftsartikel (refereegranskat)abstract
- In response to anthropogenic noise, vertebrates express modified acoustic communication signals either through individual plasticity or local population adaptation. In contrast, how insects respond to this stressor is poorly studied. Field crickets Gryllus bimaculatus use acoustic signals to attract and locate mates and are commonly found in noisy roadside environments, offering a powerful system to study the effects of anthropogenic noise on insect communication. Rapid repetition of sexual calls (chirps) is essential to attract females, but calling incurs energetic costs and attracts predators. As a result, males are predicted to reduce calling rates when background noise is high. Here, we combine observations and experimental playbacks to show that the responses of field cricket males to anthropogenic noise also depend on their previous experience with passing cars. First, we show that males living on highway edges decrease their chirp rate in response to passing cars. To assess whether this behavioral response depends on previous exposure to car noise, we then broadcast recordings of car noise to males located at different distances from the road and, therefore, with different previous exposure to car noise. Although all tested individuals responded to broadcasted traffic noise, males closest to the road decreased their chirp rate less than individuals calling further from the road. These results suggest that regular exposure to anthropogenic noise may decrease individuals' sensitivity and behavioral responses to noise, allowing them to maintain effective signaling rates. Behavioral plasticity modulated by experience may thus allow some insect species to cope with human-induced environmental stressors.
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| 7. |
- Griesser, Michael, et al.
(författare)
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From bird calls to human language : exploring the evolutionary drivers of compositional syntax
- 2018
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Ingår i: Current Opinion in Behavioral Sciences. - : Elsevier. - 2352-1546 .- 2352-1554. ; 21, s. 6-12
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Forskningsöversikt (refereegranskat)abstract
- Compositional syntax, where lexical items are combined into larger units, has been assumed to be unique to human language. Recent experiments, however, showed that Japanese tits combine alert and recruitment calls into alert-recruitment sequences when attracting conspecifics to join in mobbing a predator. We speculate that such call combinations are favoured when: Firstly, callers and receivers have shared interests in exchanging information; secondly, species produce different types of calls in different situations, leading to distinct behavioural responses in receivers; and finally, complex situations exist in which receivers benefit by combining two or more behaviours. These preconditions were also present in human ancestors. Thus, future work on bird calls may provide insights into the evolution of compositional syntax in human language.
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| 8. |
- Hoglund, Jacob, et al.
(författare)
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A hybrid snipe Gallinago gallinago x G-media found in the wild
- 2015
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Ingår i: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 156:3, s. 819-827
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Tidskriftsartikel (refereegranskat)abstract
- A hybrid snipe male was observed and caught in 2009 in the Norwegian mountains. We report behaviour, vocalizations, morphology, and genetic data for this bird. Mitochondrial and nuclear DNA sequences revealed that the hybrid had a great snipe mother and a common snipe father. The hybrid was intermediate in most measured morphometric traits and showed some intermediate plumage characteristics. The behaviour was similar to that of a great snipe-it displayed and vocalised at a great snipe lek for more than a week. The song was somewhat reminiscent of a great snipe's, but lacked the frequency-modulated whistles that are part of the great snipe song, consisting of more rapid click notes of a narrower frequency spectrum. This is the only putative hybrid that we have found among the more than 4,400 adult individuals we have examined between 1986 and 2014 at great snipe leks in Norway, Sweden, Poland, and Estonia. Common snipes invariably occur near these sites. Reports on putative hybrids among snipe species are very rare, and we question the validity of previous claims. This is the first where the parental origins-and, indeed, the hybrid status-have been unequivocally determined. We speculate on how a great snipe female, known for being extremely choosy about mating, came to mate with a common snipe male. We also note that, although perhaps behaviourally more likely, physical constraints on chick development (caused by the smaller egg size of the common snipe and larger body size of the great snipe) might prevent any successful male great snipe x female common snipe hybridisation-a possible example of an unidirectional post-zygotic barrier.
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| 9. |
- Kyogoku, Daisuke, et al.
(författare)
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Heterospecific mating interactions as an interface between ecology and evolution
- 2020
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Ingår i: Journal of Evolutionary Biology. - : Wiley. - 1010-061X .- 1420-9101. ; 33, s. 1330-1344
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Forskningsöversikt (refereegranskat)abstract
- Reproductive interference (costly interspecific sexual interactions) is well-understood to promote divergence in mating-relevant traits (i.e. reproductive character displacement: RCD), but it can also reduce population growth, eventually leading to local extinction of one of the species. The ecological and evolutionary processes driven by reproductive interference can interact with each other. These interactions are likely to influence whether the outcome is coexistence or extinction, but remain little studied. In this paper, we first develop an eco-evolutionary perspective on reproductive interference by integrating ecological and evolutionary processes in a common framework. We also present a simple model to demonstrate the eco-evolutionary dynamics of reproductive interference. We then identify a number of factors that are likely to influence the relative likelihoods of extinction or RCD. We discuss particularly relevant factors by classifying them into four categories: the nature of the traits responding to selection, the mechanisms determining the expression of these traits, mechanisms of reproductive interference and the ecological background. We highlight previously underappreciated ways in which these factors may influence the relative likelihoods of RCD and local extinction. By doing so, we also identify questions and future directions that will increase our holistic understanding of the outcomes of reproductive interference.
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| 10. |
- McFarlane, S. Eryn, et al.
(författare)
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RNA sequencing provides insight into metabolic dysfunction of hybrids between a recently diverged songbird species pair
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Hybrid dysfunction is thought to gradually build up through the accumulation of clashes between genes as they diverge between the parental species. However, analyses of genetic incompatibilities are generally biased towards long diverged species that are kept under laboratory conditions. Here, we used RNAseq to evaluate 1) whether there was differential gene expression between naturally occurring Ficedula flycatcher hybrids and parental species in energetically expensive alimentary organs, and 2) if such differential gene expression was, based on Gene Ontology (GO) terms, functionally related to Resting Metabolic Rate (RMR) and energy production. We found substantial differential gene expression in all pairwise contrasts, but fewer functional differences between the parental species than between hybrids and either parental species. Some of the differentially expressed genes underlay the OXPHOS pathway, and significantly more than expected GO terms associated with metabolic function were differentially expressed between hybrids and either parental species in the liver. Our results corroborate the idea that tightly co-evolved mitochondrial and nuclear genes underlying the Oxidative Phosphorylation (OXPHOS) pathway can become miss-matched in hybrids and cause malfunctioning phenotypes. Mitonuclear interactions affecting OXPHOS have the potential to both quickly diverge in allopatry as populations adapt to different climate regimes and to cause hybrid genetic dysfunction at secondary contact
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