Behavioral Ecology Research Articles

Does cryptic dichromatism exist in the Saffron Finch (Sicalis flaveola)? Colorimetric variables and the avian visual model

Sexual dichromatism, a particular type of sexual dimorphism, occurs in several species and has been associated with sexual selection. In some cases, the differences are so small that they are imperceptible to humans, but possibly detected by birds. The objective measurement of color with spectrophotometers and detailed analyses according to the perception ability of the avian eye have revealed that some species that were once considered to be monochromatic, are in fact dichromatic and able to perceive these differences. In the tropics, the Saffron Finch (Sicalis flaveola) does not present marked sexual dimorphism in coloration, which makes studies in behavioral ecology, natural history and population dynamics difficult. To assess whether there is dichromatism in the species, the reflectance (between 300 and 700 ​nm) of ten body regions was measured in 196 wild adults in Cali-Colombia. Sex was determined using the CHD1 gene on the sex chromosomes. Reflectance spectra were analyzed using: colorimetric variables and the avian visual model. We found that reflectance shows a bimodal curve in all body regions, except the crown. Males presented higher reflectance at long wavelengths, while for females this occurred in ultraviolet wavelengths. For the visual model, we found that there are significant intrasexual differences; however only in crown coloration is there a possible perceived difference between sexes. We conclude that in the Saffron Finch there are color differences between the sexes in all regions considering the physical phenomenon (reflectance), but in general, when evaluating color perception (avian visual model), there are no differences between the sexes in most of the body regions. The intrasexual differences are significant, indicating the possibility of these being signals that influence social interactions in the species.

Settlement cue selectivity by larvae of the destructive crown-of-thorns starfish.

Population irruptions of crown-of-thorns starfish (COTS) cause extensive degradation of coral reefs, threatening the structure and function of these important ecosystems. For population irruptions to initiate and spread, large numbers of planktonic larvae have to successfully transition into their benthic life-history stage (i.e. settlement), whereby larval behaviour and the presence of settlement cues may shape spatial patterns of recruitment and adult densities. Our results demonstrate that a wide range of coralline algae species induce COTS larvae to settle; however, the capacity to promote settlement success varied manyfold among algal species, ranging from greater than 90% in Melyvonnea cf. madagascariensis to less than 2% in Lithophyllum cf. kotschyanum and two Porolithon species at 24 h. Because many coralline algae species that promote high settlement success are prevalent in shallow reef habitats, our findings challenge the hypothesis that COTS larvae predominantly settle in deep water. Considering both larval behaviour and algal ecology, this study highlights the ecological significance of coralline algae communities in driving recruitment patterns of COTS. More specifically, the local abundance of highly inductive coralline algae (especially, Melyvonnea cf. madagascariensis) may explain some of the marked spatial heterogeneity of COTS populations and the incidence of population irruptions.

The iNaturalist platform as a source of data to study amphibians in Brazil

Based on debilitating recent budget cuts for science, Brazilian researchers had to find alternative ways to continue scientific production. Here we provide a perspective for the use of citizen-science data deposited in the iNaturalist platform as an alternative source of data to support biodiversity research. Observations contributed by volunteers can be analyzed at large spatial and temporal scales and can respond to questions in behavioral and population ecology. We analyzed this potential through the example of Brazilian amphibians, a group that is less studied worldwide than birds. In fact, to our knowledge, only two studies have been published that are based on citizen-science data for Brazilian amphibians. At the time of writing, the iNaturalist platform has over 14,800 research grade observations from Brazil, representing 698 species, a number increasing daily. Compared to other species-rich countries, volunteer-collected datasets from Brazil cover a relatively high taxonomic diversity (61%), providing a plethora of valuable data. Despite this potential, there are large spatial gaps in sampling in Brazil. Here we encourage established and budding herpetologists not only to use the platform to retrieve data, but also to contribute to iNaturalist actively, with new observations, as well as by identifying species in existing records.

Spying the dog: Wearable action camera as a tool to understand dog’s behaviour during homing (Carnivora: Canidae)

Automated data collection methods, such as using GPS collars and animal-borne cameras, represent an efficient way of data collection and may be instrumental in the research of animal orientation, including magnetoreception. In this study, we designed a wearable dog action camera (DAC) system for hunting dogs consisting of a Garmin Virb Elite camera housed in the stainless mount attached to the dog harness. We evaluated the DAC’s reliability and potential to capture various behaviour, and we tested the effect of the DAC on the dog’s activity and well-being. We found no significant impact of the DAC on the dogs’ average speed. The tested system was reliable, efficient and safe for dogs. We recorded various behaviours connected to orientation, such as olfactory behaviour and head scanning, the latter described for the first time in domestic dogs. Furthermore, we observed other important behaviours such as hunting, exploration and comfort behaviour. Using wearable action cameras for studying domestic and free-roaming tame animals can bring new opportunities for future behavioural and sensory ecology research.

Re-evaluating late Mesolithic economies

The late Mesolithic hunter-gatherers of what is now Denmark have long captivated archaeologists, who have meticulously studied the archaeological remains of their foraging economy since the mid-twentieth century. However, these studies – predominantly focused on subsistence – have often overlooked how individual decisions based on social and environmental settings can greatly structure foraging behaviours and, subsequently, the patterns observed in the zooarchaeological record. Perceiving hunting not just as an activity, but as a cultural practice shaping identities and social bonds, underscores the importance of considering social, symbolic and economic dimensions in Mesolithic hunting research. This study bridges this gap by integrating theoretical frameworks from human behavioural ecology (HBE), such as optimal foraging theory (OFT), costly signalling theory (CST) and notions of prestige. By doing so, it aims to elucidate the complex motivations underlying prey selection among the Ertebølle hunters. Through analysis of five sites from the Danish Ertebølle period (5400–3950 BC) using a simplified prey choice model (PCM), this research seeks to shed light on the interplay of ecological and social factors shaping hunting practices. The findings are discussed through the lens of optimal choice and prestige to examine patterns of prey selection at these archaeological sites.

Habitat use by the eastern pygmy-possum in a coastal woodland–heathland mosaic

Understanding patterns of habitat use is required to conserve species and to manage their habitats. I used detections of 156 individual eastern pygmy-possums (Cercartetus nanus) within artificial cavities to investigate habitat use across 18 ha of a woodland–heathland mosaic. Detection of breeding females was highest in autumn (March to May) and winter, during the flowering period of Banksia ericifolia. Detection was over two times higher in woodland compared with heathland. This pattern was not influenced by variation in flowering or hollow abundance, which were equivalent across the two habitats. Protection from the weather may drive this pattern. Adult males were detected most frequently in autumn, coinciding with the beginning of female reproduction. They were detected equally in woodland and heathland. Why detection was lower in winter and spring is unclear but may arise from female aggression, forcing males to use natural shelters away from lactating females. Subadults were detected most frequently in spring and summer, coinciding with independence and dispersal. Subadults preferred woodland, reflecting where they were reared. This study has provided new insights into the behavioural ecology of this species, but further studies are needed to better understand how foraging and breeding influence shelter site use.

Phylogenetics and the Cenozoic radiation of lampreys

The development of a movable jaw is one of the most important transitions in the evolutionary history of animals.1 Jawed vertebrates rapidly diversified after appearing approximately 470 million years ago. Today, only lampreys and hagfishes represent the once dominant jawless grade2,3,4 and comprise less than 1% of living vertebrate species. Their relationship to other vertebrates ranks among the more contentious problems in animal phylogenetics.5,6,7,8,9,10,11,12 Further, the phylogenetic relationships within lampreys and hagfishes remain unclear,13,14,15 and the ages of their living lineages are largely unexplored.16,17 Because of their importance for the genomic and developmental changes that prefigured jawed vertebrate diversity,18,19,20,21 the evolutionary history of lampreys and hagfishes is a major frontier of organismal biology. Of these two clades, lampreys22 are more ecologically diverse, exhibiting freshwater, anadromous, and fully marine forms, as well as parasitic and nonparasitic species.23,24 Here, we present a new phylogeny and historical biogeographic reconstruction of all living lampreys. Whereas the early diversification of this clade tracks Pangaean fragmentation, lampreys also rapidly radiated in the northern hemisphere during the mid-Cretaceous and directly after the Cretaceous-Paleogene extinction. These radiations mirrored concurrent ones in other animals and plants and coincided with changes to lamprey ecology and feeding behavior. Our results suggest that 80% of living lamprey clades appeared in the last 20 million years of Earth history. Rather than gradually accumulating since the oldest stem-group forms appeared in the early Paleozoic, living lamprey biodiversity results from diversifications extending from the Cretaceous to present.

Shifts in predator behaviour following climate induced disturbance on coral reefs.

Coral reefs are increasingly ecologically destabilized across the globe due to climate change. Behavioural plasticity in corallivore behaviour and short-term trophic ecology in response to bleaching events may influence the extent and severity of coral bleaching and subsequent recovery potential, yet our understanding of these interactions in situ remains unclear. Here, we investigated interactions between corallivory and coral bleaching during a severe high thermal event (10.3-degree heating weeks) in Belize. We found that parrotfish changed their grazing behaviour in response to bleaching by selectively avoiding bleached Orbicella spp. colonies regardless of bleaching severity or coral size. For bleached corals, we hypothesize that this short-term respite from corallivory may temporarily buffer coral energy budgets by not redirecting energetic resources to wound healing, and may therefore enable compensatory nutrient acquisition. However, colonies that had previously been heavily grazed were also more susceptible to bleaching, which is likely to increase mortality risk. Thus, short-term respite from corallivory during bleaching may not be sufficient to functionally rescue corals during prolonged bleaching. Such pairwise interactions and behavioural shifts in response to disturbance may appear small scale and short term, but have the potential to fundamentally alter ecological outcomes, especially in already-degraded ecosystems that are vulnerable and sensitive to change.

A mathematical framework for collective foraging behavior of social insect colonies in multi-dynamic environments

Understanding collective behavior is integral to disciplines including developmental biology, behavioral ecology, and sociology. In this investigation, we construct deterministic and stochastic models for exploring how internal factors (i.e., task demand) and external factors (i.e., dynamic environment) drive the collective foraging behavior of social insect colonies. Through theoretical analysis, we demonstrate the global stability of an interior equilibrium for the deterministic case, and study the existence of a unique stationary distribution for the stochastic case. Surprisingly, the global stability of the interior equilibrium and the existence of a unique stationary distribution of the proposed models do not depend on additional conditions. The main contribution of this work is to construct a new mathematical framework to explore the influence of internal stimulus and external fluctuation on the dynamics of social insect colonies, and to provide corresponding theoretical analysis methods.

Phylogenetically controlled life history trait meta-analysis in cetaceans reveals unexpected negative brain size and longevity correlation.

The identification of patterns in trait evolution is essential to understand the interaction of evolutionary forces, and provides useful information for species management. Cetaceans are a phylogenetically well-resolved infraorder that exhibit distinct trait variation across behavioral, molecular, and life history dimensions, yet few researchers have applied a meta-analytic or comparative approach to these traits. To understand cetacean trait evolution, we used a phylogenetic generalized least squares approach to examine the cognitive buffer hypothesis (CBH). A large brain should buffer individuals against environmental challenges through increasing survival rates, and a longer lifespan should buffer individuals against the cost of extended development for larger brains according to the CBH, leading to an expected positive correlation between brain size and lifespan. In contrast to this expectation, previously observed in taxa including primates, we found a negative correlation between brain size and lifespan in cetaceans. This suggests cetaceans experience selective pressures different from most other mammals in these traits but may be more similar to some social mammalian carnivores that display alloparenting. We also provide a comprehensive dataset to explore additional aspects of trait evolution but which would greatly benefit from studies on behavioral ecology across cetaceans and increased focus on data deficient species.

Temporal distribution, reproductive synchrony, and mating patterns of the explosive breeder frog Dermatonotus muelleri (Anura: Microhylidae)

The knowledge about natural history of a species is fundamental for the proposition of theories in population, community, and behavioral ecology. Dermatonotus muelleri (Boettger, 1885) is one of the several Neotropical anuran species that still lacks basic information. These frogs are widely distributed in South America and present many peculiar morphological features, such as a reduced head size and a tongue morphology that suggests a specialized diet in ants and termites. However, D. muelleri is rare in anuran surveys, because of the explosive breeding behavior, which restrict its occurrence in aquatic habitats to few days a year, and the semi-fossorial habit, making the individuals inactive during most part of the year. In this study, we describe the reproductive ecology of Dermatonotus muelleri, with special attention to the mechanisms that regulates (i) the reproductive synchrony between males and females and (ii) the operational sex ratio (OSR), and (iii) if size is a good predictor of pairs formation (assortative mating).

Ecology, evolution, and conservation of Ethiopia’s biodiversity

Ethiopia is home to one of the richest and most unique assemblages of fauna and flora on the African continent. Contained within its borders are two major centers of endemism, the mesic Roof of Africa (also known as the Ethiopian Highlands) and the arid Horn of Africa, resulting from the country’s varied topography and consequent geographic isolation. These centers of endemism are crucial to global conservation as evidenced by their classification within the Eastern Afromontane and Horn of Africa biodiversity hotspots, respectively. Ethiopia’s diverse ecosystems and the biodiversity they contain are increasingly threatened by climate change and the growing impacts of Africa’s second largest human and largest livestock populations. In this paper, we focus on several key areas of recent and ongoing research on Ethiopian biodiversity that have broadened our understanding of nature and its conservation in Africa. Topics explored include the behavioral ecology of Ethiopia’s large social mammals, the ecology and conservation of its unique coffee forests, and Ethiopian approaches to community conservation, fortress conservation, and nature-based solutions. We also highlight the increasing prominence of Ethiopian scientists in studies of the country’s biodiversity in recent decades. We suggest promising avenues for future research in evolutionary biology, ecology, systematics, and conservation in Ethiopia and discuss how recent and ongoing work in Ethiopia is helping us better understand and conserve nature in the human-dominated landscapes of Africa and other tropical regions today.

Home-Range Size and Space Use of Territorial Bonelli’s Eagles (Aquila fasciata) Tracked by High-Resolution GPS/GSM Telemetry

High-resolution GPS/GSM dataloggers provide spatial information of the highest quality, which outperform previous tracking methods, such as Argos telemetry or conventional VHF ground-tracking. As a result, this has improved our knowledge of home-range behavior and spatial ecology of many species, including large raptors. In this paper, we use high-resolution GPS/GSM dataloggers to assess the home-range size and the role of sex, season (breeding or non-breeding season), and breeding status (reproductive or non-reproductive individuals) on the space use of Bonelli’s eagle (Aquila fasciata). To this end, 51 territorial individuals (25 females and 26 males) were equipped with GPS/GSM transmitters and were tracked over 7 years (2015–2021) in eastern Spain. Overall, we recorded 4,791,080 fixes that were analyzed through kernel density methods (50%, 75%, and 95% fixed kernels). The average individual home-range size according to the 95%, 75%, and 50% kernels was 54.84 ± 20.78 km2, 24.30 ± 10.18 km2, and 11.17 ± 4.90 km2, respectively. Overall, the home-range size of individuals occupying the same territory was similar, mainly due to the cooperative hunting behavior exhibited by the species. We did not find interannual differences in the home-range size (95% fixed kernel) of the majority of individuals, showing a strong territorial fidelity of the breeding pairs. In general, females’ home-range size was slightly smaller than males’ size due to the decrease in activity in the breeding season as a result of laying, incubation, and chick attendance at nests. No seasonal variation in the 95% kernel was found, but it was found in the 75% and 50% kernels. In regard to the breeding status, higher home-range size was recorded in the non-reproductive individuals. Moreover, we found a low neighbor overlap among the territories (4.18% ± 3.06%), which evidences a high level of intraspecific competition in the Bonelli’s eagle. Finally, this study highlights the advantages of the use of accurate telemetry information to improve our understanding of the spatial ecology of the endangered Bonelli’s eagle, which ultimately will serve to better inform management actions for its conservation.

Increased food availability at offshore wind farms affects trophic ecology of plaice Pleuronectes platessa

Offshore wind farms (OWFs) and their associated cables, foundations and scour protection are often constructed in soft-sediment environments. This introduction of hard substrate has been shown to have similar effects as artificial reefs by providing food resources and offering increased habitat complexity, thereby aggregating fish around the turbines and foundations. However, as most studies have focused their efforts on fish species that are typically associated with reef structures, knowledge on how soft sediment species are affected by OWFs is still largely lacking. In this study, we analysed the trophic ecology and condition of plaice, a flatfish species of commercial interest, in relation to a Belgian OWF. The combination of a stomach and intestine content analysis with the use of biomarkers (i.e. fatty acids and stable isotopes) identified a clear shift in diet with increased occurrences of typical hard-substrate prey species for fish in the vicinity of the foundations and this both on the short and the long term. Despite some condition indices suggesting that the hard substrate provides increased food availability, no clear increases of overall plaice condition or fecundity were found. Samples from within the wind farm, however, contained larger fish and had a higher abundance of females compared to control areas, potentially indicating a refuge effect caused by the cessation of fisheries activities within the OWF. These results suggest that soft-sediment species can potentially benefit from the presence of an OWF, which could lead to fish production. However, more research is still needed to further elucidate the behavioral ecology of plaice within OWFs to make inferences on how they can impact fish populations on a larger spatial scale.

Editorial: Nesting in reptiles: Natural and anthropogenic threats and evolutionary responses

EDITORIAL article Front. Ecol. Evol., 06 December 2022Sec. Behavioral and Evolutionary Ecology Volume 10 - 2022 | https://doi.org/10.3389/fevo.2022.1103193

Home range and activity patterns of the Critically Endangered endemic pygmy raccoon of Cozumel Island, México

AbstractIndividuals from island and continental mammal populations have shown a number of differences in their behavioral ecology. We predicted that, like other island carnivores exhibiting dwarfism, the pygmy raccoon (Procyon pygmaeus), a Critically Endangered carnivore endemic to Cozumel Island, México, would show differences in its home ranges and activity patterns when compared to its mainland counterpart, the racoon, P. lotor. We radio-tracked 11 individuals (six males, five females) from February to July 2017 and used location data derived from triangulation to estimate the home range size, diel activity patterns, and distances traveled of pygmy raccoons. Individuals showed an average home range size between 96.9 ± 18.8 ha (95% minimum convex polygon) and 123.3 ± 31.2 ha (95% fixed kernel). Home ranges of males (109.4–142.8 ha) were larger than those of females (81.8–99.9 ha). Average home ranges were in the lower extreme of those reported for continental raccoons. Activity patterns of pygmy raccoons generally begin at sunset and continue up to 04:00 with rare activity peaks during the day; there were no significant differences in activity patterns between sexes. Data on spatial needs of individuals, and differences between sexes or insular versus continental populations have implications for conservation planning and management.

Research status and development trend of altruism in the biological field - knowledge graph analysis based on CiteSpace

Based on the visualization analysis of foreign literature on altruistic behavior in recent ten years (2012-2022) by CiteSpace, it is found that the research on altruistic behavior in the field of biology abroad has experienced the initial exploratory stage, the outbreak stage, and now enters the stable and deepening stage. The discipline distribution is mainly behavioral ecology, supplemented by evolutionary biology, biomathematics, and genetics. The author has three main cooperative groups, and a relatively tight cooperative network has been formed locally in related fields. From the perspective of cooperation degree, the cooperation density of major research institutions is high, and relevant research has been relatively mature. Judging from the period calculated in the software, altruism, cooperation, kin Selection, reciprocity, and inclusive fitness emerged earlier. In recent years, constitutive theory, density dependence, and Habitat construction have emerged, which may become a new direction for future research. Therefore, future research can expand the scope of disciplines, strengthen the cooperation between authors and units, and explore other research hotspots.

Increasing seawater temperatures in the Levantine Basin, eastern Mediterranean, may elicit increased activity in slipper lobsters, Scyllarides latus (Latreille, 1803) (Decapoda: Achelata: Scyllaridae)

Abstract Temperature is a predominant motivator for movement and activity over a wide range of mobile marine ectotherms. Water temperature modulates the movements of many lobster species, which can vary widely over spatial and temporal scales. Providing insight into the thermal preferences (and refuges) that some lobsters seek remains a key tenet to our understanding of the behavioral ecology of these animals. The Mediterranean slipper lobster, Scyllarides latus (Latreille, 1803), shows seasonal movements throughout most of its range and is subject to a changing thermal environment. Through a series of laboratory-based trials, we examined the movement activity of S. latus and tested the hypothesis that S. latus engage in increased movements when subjected to temperatures outside their preferred range. To examine this, we exposed a set of lobsters (N = 10, CLavg= 83.1 ± 6.1 cm) to the same thermal profiles as in the field and assayed their locomotion using activity wheels. Our laboratory results showed that individuals of S. latus are more active at higher temperatures during dawn hours and revealed that warming water temperatures elicited markedly longer movements over a similar timeframe. Combined, these findings suggest that increasing water temperatures in the eastern Mediterranean (Levant) may affect lobster movements and could alter seasonal patterns of distribution as well.

Automated tracking of aquatic crustaceans with potential application on the quantification of animals movement

Here, we present a set of algorithms using the Python programming language, that will allow using a routine for object detection and tracking in experimental videos. We developed a script, under the fundamentals of background subtraction and image thresholding (using the OpenCV package), that makes it possible to track a wide spectrum of animals under different conditions. We have validated this script through testing on semi-terrestrial and aquatic crustacean species and under different experimental scenarios (laboratory and field sampling and using video created under nocturnal and diurnal conditions). The open-source nature of the script allows for flexibility and scalability, so it can be easily customized and is thus transferable to other species/experiments in the context of behavioral ecology. The tracking script is easy customizable and free alternative to commercial video tracking systems and therefore, applicable to a wide variety of both educational and research programs.

The challenges of primate research and conservation in Paraguay


 
 
 The primate fauna of Paraguay consists of just five species (Sapajus cay, Alouatta caraya, Aotus azarae, Plecturocebus pallescens and Mico melanurus) and has been largely overlooked by the international primatological community. Not-withstanding, Paraguay currently has the second highest deforestation rate in Latin America and the threats facing Paraguayan primates are as severe as anywhere else on the continent. Primate conservation in Paraguay is complicated by the complete absence of a homegrown primatological research community and the country lacks the solid biological research foundation required for the development of robust management strategies. Only one university degree in biology is available in the country (with the Universidad Nacional de Asunción), and opportunities for postgraduate education in biological sciences require studying abroad, whilst the limited number of career opportunities upon graduation mean that those receiving such training frequently prefer to pursue their career elsewhere rather than return to the country to practice. No higher education courses in primatology are currently available in Paraguay. Fundación Para La Tierra (PLT) is a Paraguayan conservation and education NGO (80086144-2), founded in 2010. PLT focuses on conservation of Paraguay’s natural habitats through scientific research, community engagement and education, and implements Paraguay’s only long-term primatology research projects: the “Hooded Capuchin Project” conserving Sapajus cay in what little remains of the Upper Paraná Atlantic Forest and the “Urban Howler Monkey Project” researching the behavioural ecology of Alouatta caraya inhabiting the city of Pilar. The PLT primate projects adopt a multi-faceted approach: long-term scientific research, training and supporting local people with an interest in primates, supervision of international students and environmental education in schools. In this article we will discuss the challenges of develop- ing such a project, and a vision for the future of primatology in Paraguay.