Biology subjects

Gilman, R. T.

Publications and source records attributed to Gilman, R. T..

7 recordsLinked to original sources

bioRxiv2024

Song preferences in female Java Sparrows: Familiarity or Complexity?

Songs play an important role in mate choice for many bird species. Females of some species prefer mates with song characteristics such as complexity, or with specific temporal or note features. In some species, females also prefer familiar songs, or songs that are acoustically similar to those of their fathers. These different aspects of songs may provide distinct information about the birds that produced those songs. For example, perceived familiarity may be a signal of local adaptation, locally relevant information or learned behaviours, or genetic compatibility, while song complexity may be a signal of overall genetic quality or ability to provide parental care. As a result, multiple axes of variation could influence female song preferences. We examined female preference for song familiarity and complexity using the Java sparrow (Lonchura oryzivora) as a model species. Females were presented with two pairs of song stimuli. In one pair one song was from the females father or from a social relative with an acoustically similar song and the other was unfamiliar. In the other pair the songs differed in two aspects of complexity: note repertoire and linearity. Females preferred their fathers songs over unfamiliar songs, but we did not find strong evidence that females generalized this preference to other socially related individuals. Females also preferred complex songs, specifically those with larger note repertoires and lower linearity. Our results suggest that female song preference in Java sparrows is multi-faceted, and females may obtain multiple kinds of information from male song.

animal behavior and cognition↗

bioRxiv2023

Java sparrow song conforms to Mezerath's Law but not Zipf's Law of Abbreviation

Linguistic laws, which describe common statistical patterns in human language, are often studied in animal communication systems. Despite good evidence for adherence to these laws in non-human primate communication, there is still a paucity of data on other taxa. Birdsong is often used as a model for human language development due to similarities in vocal learning processes. Investigating whether birdsong also adheres to linguistic laws may provide further value or help determine the limitations of such comparisons. Here, we looked for patterns consistent with Menzeraths law, the tendency for longer sequences to be made up of smaller constituent parts, and Zipfs Law of Abbreviation, the tendency for more frequently used elements to be shorter in length, in the songs of Java sparrows (Padda oryzivora). We found that songs conformed to Menzeraths law at both the population and individual level; longer sequences were made up of shorter notes. This pattern was achieved through note type selection rather than the shortening of existing note types. Adherence to Menzeraths law may reflect species-specific constraints on song durations. We found no evidence to support adherence to Zipfs Law of Abbreviation, either at population or individual level; more frequently used notes were not shorter in length. However, as repertoire size in Java sparrows is small, we expect our power to detect Zipfs Law of Abbreviation to be weak. Whilst there may be some limitations in applying linguistic laws derived from human language to birdsong, especially Zipfs Law of Abbreviation, these laws may still provide insights into animal and human communication systems.

animal behavior and cognition↗

bioRxiv2023

Does Zipf's law of abbreviation shape birdsong?

Zipfs law of abbreviation predicts that in human languages, words that are used more frequently will be shorter than words that are used less frequently. This has been attributed to the principle of least effort - communication is more efficient when words that are used more frequently are easier to produce. Zipfs law of abbreviation appears to hold for all human languages, and recently attention has turned to whether it also holds for animal communication. In birdsong, which has been used as a model for human language learning and development, researchers have focused on whether more frequently used notes or phrases are shorter than those that are less frequently used. Because birdsong can be highly stereotyped, have high interindividual variation, and have phrase repertoires that are small relative to human language lexicons, studying Zipfs law of abbreviation in birdsong presents challenges that do not arise when studying human languages. In this paper, we describe a new method for assessing evidence for Zipfs law of abbreviation in birdsong, and we introduce the R package ZLAvian to implement this analysis. We used ZLAvian to study Zipfs law of abbreviation in the songs of 11 bird populations archived in the open-access repository Bird-DB. We did not find strong evidence for Zipfs law of abbreviation in any population when studied alone, but we found weak trends consistent with Zipfs law of abbreviation in 10 of the 11 populations. Across all populations, the negative correlation between phrase length and frequency of use was several times weaker than the negative correlation between word length and frequency of use in human languages. This suggests that the mechanisms that underlie this correlation may be different in birdsong and human language.

animal behavior and cognition↗

bioRxiv2023

Lysogeny destabilizes computationally simulated microbiomes

BackgroundThe Anna Karenina Principle predicts that stability in host-associated microbiomes correlates with health in the host. Microbiomes are ecosystems, and classical ecological theory suggests that predators impact ecosystem stability. Phages can act as predators on bacterial species in microbiomes. However, our ability to extrapolate results from existing ecological theory to phages and microbiomes is limited because some phages can stage lysogenic infections, a process with no precise analog in classical ecology. In lysogenic infections, so-called "temperate" phages integrate into the cells of their hosts where they can remain dormant as prophages for many generations. Prophages can later be induced by environmental conditions, whereupon they lyse their host cells and phage progeny are released. It has been suggested that prophages can act as biological timebombs that destabilize microbial ecosystems, but formal theory to support this hypothesis is lacking. ResultsWe studied the effects of temperate and virulent phages on diversity and stability in computationally simulated microbiomes. The presence of either phage type in a microbiome increased bacterial diversity. Bacterial populations were more likely to fluctuate over time when there were more temperate phages in the system. When microbiomes were disturbed from their steady states, both phage types affected return times, but in different ways. Bacterial species returned to their pre-disturbance densities more slowly when there were more temperate phage species, but cycles engendered by disturbances dampened more slowly when there were more virulent phage species. ConclusionsPhages shape the diversity and stability of microbiomes, and temperate and virulent phages impact microbiomes in different ways. A clear understanding of the effects of phage life cycles on microbiome dynamics is needed to predict the role of microbiome composition in host health, and for applications including phage therapy and microbiome transplants. The results we present here provide a theoretical foundation for this body of work.

ecology↗

bioRxiv2023

Assessing the effect of zoo closure on the soundscape using multiple measures

The zoo soundscape has a number of important implications for animal welfare, management, and conservation. However, despite its importance, the zoo soundscape is yet to be examined in depth using multiple measures. Consistent human presence can influence the zoo soundscape. However, it is difficult to determine the specific impact of human presence, as visitors are usually present during the day when animals are active. The COVID-19 lockdown in 2020 provided a unique opportunity to study zoo soundscapes in the absence of visitors. We compared the sound environment during the 2020 closure period to a comparable open period in 2019 across three zoo aviaries, examining broad band frequency measures of sound pressure levels, sound pressure levels in defined frequency bands, and acoustic indices (Acoustic Complexity Index and Normalized Difference Soundscape Index) to describe the zoo soundscape. Acoustic indices have not, to our knowledge, previously been used in the zoo setting, although they may provide a useful metric to assess sound disturbance. Therefore, we also used this natural experiment to explore how successful these measures may be in assessing disturbances in captive environments. We found a significant effect of human presence on the sound environment; aviaries were generally quieter with less low frequency noise and with a greater proportion of biotic sound during the 2020 zoo closure period. We argue that NDSI could be a useful index for determining anthropogenic disturbance in zoos, although further information on how it is influenced by additional factors, such as human speech, would be beneficial. The use of multiple measures to assess the sound environment in zoos can provide additional information beyond loudness, such as frequencies where sound energy is concentrated and characteristics of the soundscape, which could be used to better target management and mitigation.

ecology↗

bioRxiv2021

The genetic diversity of honeybee colonies predicts the gut bacterial diversity of individual colony members

O_LIThe gut microbiota of social bees is relatively simple and dominated by a core set of taxa that have been reported consistently in individual workers from around the world. Yet, variation remains, and this has been shown to affect host health. C_LIO_LIWe characterised the individual- and regional-scale variation in the honeybee (Apis mellifera) gut microbiota in the North West of England, and asked whether the microbiota was influenced by host genotype or landscape composition. C_LIO_LIWe collected multiple honeybees from 64 colonies, and sequenced the V4 region of the 16S rRNA gene to characterise the mid- and hindgut bacterial communities. We characterised the genotype of each individual honeybee, and also the land cover surrounding each colony. C_LIO_LIThe literature-defined core taxa consistently dominated across the region, despite the varied environments. However, there was variation in the relative abundance of core taxa, and colony membership explained a large proportion of this variation. Individuals from more genetically diverse colonies had more diverse microbiotas, but individual genetic diversity did not influence gut microbial diversity. There was a trend for colonies in more similar landscapes to have more similar microbiota, whilst bees from more urban landscapes had a slightly less diverse microbiota than those from less urban landscapes. C_LIO_LIOur study provides, to our knowledge, the first demonstration for any species that the gut bacterial communities of individuals can be influenced by the genotypes of other conspecifics in the population. This is particularly important for social organisms, such as honeybees, as colony rather than individual genetic diversity appears to drive gut microbial diversity, a factor related to colony health. C_LI

ecology↗

bioRxiv2018

Reproductive skew affects social information use

Individuals vary in their propensity to use social learning, the engine of cultural evolution, to acquire information about their environment. The causes of those differences, however, remain largely unclear. Individuals that experience high reproductive skew are expected to favour high-risk strategies, whereas those that experience low reproductive skew are expected to favour risk-averse strategies. Using an agent-based model, we tested the hypothesis that differences in energetic requirements for reproduction affect the value of social information. We found that social learning is associated with lower variance in yield and is more likely to evolve in risk-averse low-skew populations than in high-skew populations. Reproductive skew may also result in sex differences in social information use, as females tend to be more risk averse than males. To explore how risk may affect sex differences in learning strategies, we simulated learning in sexually reproducing populations. Where both sexes share the same environment they adopt more extreme learning strategies, approaching pure individual or social learning. These results provide insight into the conditions that promote individual and species level variation in social learning and so may affect cultural evolution.

evolutionary biology↗