Periodic Reporting for period 1 - BRAINY (The role of behavioural flexibility on the generation and maintenance of diversity)
Berichtszeitraum: 2020-04-01 bis 2022-03-31
Organism behaviour represents the key link between the morphology of a species and its ecological role in an ecosystem. Classic theory suggests that changes in behaviour could have an important role in generating ecological divergence although empirical evidence remains scarce. In this project, I use birds as a study model to explore the role of behavioural flexibility in the generation and maintenance of species diversity. First, we found that morphological and ecological specialization are not always linked, as different ecological niches imply different degrees of specialization on foraging techniques among physical states (i.e. air, water, ground/surface). Then, we show that specialization to these different tasks is linked to changes in relative brain size, with species developing multiple tasks having relatively larger brains. Finally, we use a global radiation of birds to show that larger relative brain size was associated with an increase in rates of speciation and phenotypic evolution. Overall, our results suggest that intelligence is tightly linked with a wider foraging niche and might explain the success of certain clades in the colonization and diversification in novel environments.
The work performed can be distinguished in several sections, including (1) data acquisition, (2) achieved results, (3) communication and dissemination of the results.
1. Data acquisition
For this project, we first have compiled quantitative information on external morphology and foraging niches for all bird species. This has been a collaborative effort with Dr. Alex Pigot (UCL) and Dr. Joseph Tobias (Imperial College London). Part of this data has already been published as the AVONET database (Tobias et al. 2022 Ecology Letters), where I have participated. The second part of the data acquisition objectives were brain size measurements. We combined the compilation of published information from literature sources with additional skull measurements for specimens from the Natural History Museum, obtaining data for more than 3000 species.
2. Achieved results
Objective 1: Explore the role of behaviour in the link between morphology and the ecological niche (WP1.1).
We initially explored the relationship between morphological and ecological specialization. Despite being a common assumption, this link has rarely been tested. We quantified main axes of body shape in birds and found that that specialization in species foraging behavior does not always correspond to extreme morphologies. Instead, we find that species with extreme body shapes are associated with specialization to three fundamental locomotory tasks related to movement through air, water or across solid surfaces. This specialization in locomotion is decoupled from specialization in species foraging niche because while some specialist niches involve utilizing multiple physical states and thus locomotory tasks, others (e.g. aerial foraging) do not.
Objective 2 (WP1.2): Better understand the link between intelligence (i.e. brain size) and niche breadth.
It has generally been expected that, for a given morphology, larger brain size should allow species to exploit a wider ecological niche, in terms of a greater variety of resources and/or foraging behaviours. Using data on brain size for 3068 species, we found that species foraging along two or more foraging domains (i.e. using strategies that imply both aerial and terrestrial foraging manoeuvres) had a larger relative brain size. In addition, we found that different foraging strategy can substantially increase predictive power of relative brain size for different niche, rather than differences in diet alone.
Objective 3 (WP3 and WP4): Test how differences in cognition can affect the rates of speciation and morphological evolution.
This objective has been developed in collaboration with researchers from Washington University in St. Louis (US) and CREAF (Spain). We show that Corvus experienced a massive expansion of the climatic niche that was coupled with a substantial increase in the rates of species and phenotypic diversification. The initiation of these processes coincided with the evolution of traits that promoted niche expansion (i.e. a larger relative brain size and higher dispersal ability). These findings suggest that rapid global radiations may be better understood as processes in which high dispersal abilities synergise with traits that, like cognition, facilitate persistence in new environment (Garcia-Porta et al., 2022 Nature Communications).
3. Dissemination and communication of results
I have presented my research at several national and international conferences: British Ecological Society annual meeting 2020 (14-18th December 2020), BES Macro 2021 (5-7th July 2021), Early Career Biogeographers Conference (Oct 14-18th 2021), and XV SECEM Congress (4-7th Dec 2021).
For the communication of my results to wider audiences, I visited a school in London (The Lammas School, https://lammas-gst.org/(öffnet in neuem Fenster)) and met students of year 14-15, sharing with them my experience about working on academia and my research topic.
1. Data acquisition
For this project, we first have compiled quantitative information on external morphology and foraging niches for all bird species. This has been a collaborative effort with Dr. Alex Pigot (UCL) and Dr. Joseph Tobias (Imperial College London). Part of this data has already been published as the AVONET database (Tobias et al. 2022 Ecology Letters), where I have participated. The second part of the data acquisition objectives were brain size measurements. We combined the compilation of published information from literature sources with additional skull measurements for specimens from the Natural History Museum, obtaining data for more than 3000 species.
2. Achieved results
Objective 1: Explore the role of behaviour in the link between morphology and the ecological niche (WP1.1).
We initially explored the relationship between morphological and ecological specialization. Despite being a common assumption, this link has rarely been tested. We quantified main axes of body shape in birds and found that that specialization in species foraging behavior does not always correspond to extreme morphologies. Instead, we find that species with extreme body shapes are associated with specialization to three fundamental locomotory tasks related to movement through air, water or across solid surfaces. This specialization in locomotion is decoupled from specialization in species foraging niche because while some specialist niches involve utilizing multiple physical states and thus locomotory tasks, others (e.g. aerial foraging) do not.
Objective 2 (WP1.2): Better understand the link between intelligence (i.e. brain size) and niche breadth.
It has generally been expected that, for a given morphology, larger brain size should allow species to exploit a wider ecological niche, in terms of a greater variety of resources and/or foraging behaviours. Using data on brain size for 3068 species, we found that species foraging along two or more foraging domains (i.e. using strategies that imply both aerial and terrestrial foraging manoeuvres) had a larger relative brain size. In addition, we found that different foraging strategy can substantially increase predictive power of relative brain size for different niche, rather than differences in diet alone.
Objective 3 (WP3 and WP4): Test how differences in cognition can affect the rates of speciation and morphological evolution.
This objective has been developed in collaboration with researchers from Washington University in St. Louis (US) and CREAF (Spain). We show that Corvus experienced a massive expansion of the climatic niche that was coupled with a substantial increase in the rates of species and phenotypic diversification. The initiation of these processes coincided with the evolution of traits that promoted niche expansion (i.e. a larger relative brain size and higher dispersal ability). These findings suggest that rapid global radiations may be better understood as processes in which high dispersal abilities synergise with traits that, like cognition, facilitate persistence in new environment (Garcia-Porta et al., 2022 Nature Communications).
3. Dissemination and communication of results
I have presented my research at several national and international conferences: British Ecological Society annual meeting 2020 (14-18th December 2020), BES Macro 2021 (5-7th July 2021), Early Career Biogeographers Conference (Oct 14-18th 2021), and XV SECEM Congress (4-7th Dec 2021).
For the communication of my results to wider audiences, I visited a school in London (The Lammas School, https://lammas-gst.org/(öffnet in neuem Fenster)) and met students of year 14-15, sharing with them my experience about working on academia and my research topic.
The main scientific advance of this project is to provide fundamental understanding of the link between intelligence, ecological roles of species and its potential consequences for speciation and extinction processes. So far, we show that realized foraging niches are a combination of morphological specialization and behavioural flexibility, emphasising the role of behaviour in niche evolution.
In addition, the results can also become a first step to prioritize conservation measures for target species with high impact on ecosystems. For instance, future work could explore which ecological roles and functions might be more rapidly disrupted by anthropogenic impacts, as species with low behavioural flexibility or highly specialized functions are expected to be more threatened by extinction.
In addition, the results can also become a first step to prioritize conservation measures for target species with high impact on ecosystems. For instance, future work could explore which ecological roles and functions might be more rapidly disrupted by anthropogenic impacts, as species with low behavioural flexibility or highly specialized functions are expected to be more threatened by extinction.