A kulturális evolúció nyomai az örvös légykapó (Ficedula albicollis) énekében

A kulturális evolú ció folyamata – mely nem genetikai úton öröklött, hanem szociális tanulás útján, egyedek vagy generációk között történő információáramláson alapul – az emberré válás egyik fő mozgatórugója. Ez a kulturális evolúció azonban nemcsak az emberre jellemző sajátosság, hanem az állatok esetében is nagy jelentőséggel bír. A kulturális evolúció e gyik alapfeltétele, hogy az egyedek viselkedési elemeket másolnak egymásról. Amikor ilyen másolásra kerül sor az éneklő m a- darak között, akkor az énekelemek, vagyis a szillablák használatának eloszlása térben és időben nem véletlenszerű, hanem strukturált lesz. Ennek a hipotézisnek a tesztelésére az örvös légykapó ( Ficedula albicollis ) egy pilisi populációjában 103 hím egyed 2005 és 2010 között rögzített 1740 énekét el e- me z tük. Populációs szinten 476 szillablafajtát definiáltunk. Az egyedek szillablahasználatában me g- mutatkozó átfedések feltárására hasonlósági mátrixokat számoltunk ki , és ezek között Mantel - teszttel vizsgáltuk, hogy a hímek énekének hasonlósága mutat - e térbeli és időbeli mintázatokat. A populáció énekösszetételében időbeli strukturáltságot írtunk le: az időben egymáshoz közelebb éneklő hímek éneke jobban hasonlít egymá shoz, mint az időben egymástól távol abb éneklő hímek é. Ezek az időbeli mintázatok léptékfüggőek voltak . A térbeli mintázat megléte nem volt statisztikailag igazolható . E n- nek hiánya indokolható a rendelkezésre álló adatok alacsony számával , illetve, hogy kis geográfiai távolságokon esetleg nem kimutatható a térbeli mintázat. Összefoglalva tehát vizsgálatunkkal rés z ben igazoltuk a kulturális evolúció meglétét az örvös légykapónál

Minimum spanning tree as a new, robust repertoire size comparison method: simulation and test on birdsong

The comparison of acoustic complexity across individuals is often essential for understanding the evolution of acoustic signals. In many animal taxa, as a proxy of acoustic complexity, repertoire size is intensively studied; however, its estimation is challenging in species with large repertoires, as this process is time-consuming and may involve considerable subjectivity for the classification of signal elements. Here, we propose a novel application of the minimum spanning tree (MST) method for comparing individuals’ signal complexity, an approach that does not require classification process. We suggest that the differences in the MST length predict the differences in the repertoire sizes between individuals. To evaluate these proposals, first, we performed a simulation study investigating the effect of the practically important variables (repertoire size, number of acoustic parameters, sample size, distribution of element types and within-group variance) on the MST length. Second, we compared repertoire size estimates from the same song data from male collared flycatchers obtained using the fully manual, computer-aided manual and MST methods. In our simulation study, we found that the repertoire size strongly correlated with MST length. We also found significant effects of sample size, number of parameters and within-group variance, as well as how uniformly the samples were distributed between the groups, on the MST length. Our empirical data also revealed a strong correlation between the computer-aided manual estimation of repertoire sizes and MST length, which was comparable to the correlation between the estimations of repertoire size obtained using the two different manual methods. Therefore, we suggest using the MST method to compare the acoustic complexity among individuals in birds and other animals, with the practical restrictions suggested by our simulation results.This study was supported by funds from the Ministry of Economy and Competitiveness (Spain; CGL2015-70639-P); Hungarian Scientific Research Fund (K-75618, K-105517); National Research, Development and Innovation Office (NKFIH; K-115970, PD-115730), Erdők a Közjóért Alapítvány; and Pilisi Parkerdő Zrt

Short- and long-term repeatability and pseudo-repeatability of bird song: sensitivity of signals to varying environments

To provide reliable information about individual-specific characteristics, sexual signals should be consistently displayed within an individual at least within a particular social context or time window. However, some male traits, like bird song, depict extreme within-individual variations even within a very short time frame. To investigate the extent by which acoustic displays in male collared flycatchers (Ficedula albicollis) reveal consistent individual-specific attributes or more flexible characteristics, we assessed the repeatability of various song traits at different sampling regimes (within-day, between-day, and between-year contexts). Repertoire size showed considerably high and significant repeatability (R > 0.25) in all temporal contexts suggesting that it can potentially indicate an individual attribute that is shaped by genetic background, permanent environmental effects, or long-term experience. Song rate, song length, mean frequency and frequency bandwidth, tempo of syllables, and within-song complexity had small-to-moderate repeatability (R < 0.25) that was significant for the within-day scenario only. Environmental effects can confound repeatability estimates, as males that changed nest boxes between song recordings performed with lower consistency than those that systematically sang on the same territory. Hence, the characteristics of particular songs could reveal aspects that are sensitive to changes in the environment rendering a signal function to the within-individual variance of songs. The consistency of acoustic signals and their sensitivity to the environment determines what kind of information can be conveyed to the receivers.This study was supported by funds from The Ministry of Economy and Competitiveness (Spain) (CGL2015-70639-P), the Hungarian Scientific Research Fund (K-75618, K-101611, K-105517), the National Research, Development and Innovation Office (NKFIH, K-115970, and PD-115730), the Erdők a Közjóért Alapítvány, and the Pilisi Parkerdő Zrt. GH was also funded by the János Bólyai Research Scholarship of the Hungarian Academy of Sciences.Peer reviewe

song_distance

Dissimilarity in song content among males based on the frequency of use of particular syllable

Data from: MHC-mediated sexual selection on bird song: generic polymorphism, particular alleles and acoustic signals

Several hypotheses predict that the major histocompatibility complex (MHC) drives mating preference in females. Olfactory, color or morphological traits are often found as reliable signals of the MHC profile, but the role of avian song mediating MHC-based female choice remains largely unexplored. We investigated the relationship between several MHC and acoustic features in the collared flycatcher (Ficedula albicollis) a European passerine with complex songs. We screened a fragment of the class IIB 2nd exon of the MHC molecule, of which individuals harbor 4-15 alleles, while considerable sequence diversity is maintained at the population level. To make statistical inferences from a large number of comparisons, we adopted both null-hypothesis testing and effect size framework in combination with randomization procedures. After controlling for potential confounding factors, neither MHC allelic diversity nor the presence of particular alleles was associated remarkably to the investigated qualitative and quantitative song traits. Furthermore, genetic similarity among males based on MHC sequences was not reflected by the similarity in their song based on syllable content. Overall, these results suggest that the relationship between features of song and the allelic composition and diversity of MHC is not strong in the studied species. However, a biologically-motivated analysis revealed that individuals that harbor an MHC allele that impairs survival perform songs with broader frequency range. This finding suggests that certain aspects of the song may bear reliable information concerning the MHC profile of the individuals, which can be used by females to optimize mate choice

genetic_distance

Genetic distance of individuals (with information on qualitative song traits) based on their MHC sequence

quantitative_song_traits

Individual-specific estimates of quantitative song traits, number of MHC alleles, and the presence of particular MHC alleles. This dataset was used to test if quantitative song traits reflect MHC allelic diversity or the presence of particular allele

qualitative_song_traits

Individual-specific estimates of syllable content (presence of particular syllables), and the number of MHC alleles. This dataset was used to test if qualitative song traits reflect MHC allelic diversity. To test if the presence of particular syllables are associated with the presence of particular alleles, this dataset should be merged with "quantitative_song_traits.xlsx" based on ring number