Biology subjects

Bartumeus, F.

Publications and source records attributed to Bartumeus, F..

9 recordsLinked to original sources

bioRxiv2026

Predicting seabird-vessel interactions from bird-borne data alone

Seabirds often follow fishing vessels to scavenge discards and bait, benefiting from access to food but also facing the risk of bycatch. Exposure to bycatch is commonly assessed by analysing seabird-fishing interactions, typically through the spatiotemporal alignment of seabird and vessel tracking data. However, this approach may underestimate interactions when vessel tracking information is incomplete or unavailable. We tested whether seabird-vessel interactions could be identified using seabird telemetry alone and whether fishing and nonfishing vessels could be distinguished. We analysed GPS, wet-dry, accelerometer and pressure data from 273 Scopoli's shearwaters in the Northwest Mediterranean. We identified 779 vessel-attendance events using seabird GPS, Automatic Identification System (AIS) data and simulation-based tests to distinguish vessel attraction or following from chance encounters. We then trained random forest models to predict vessel-attendance from bird-borne movement and environmental metrics, testing different sensor combinations. Finally, we selected the GPS and environmental model for its performance and compatibility with GPS-only tracking data from 17 radar-equipped shearwaters, whose detectors identified nearby vessels independently of AIS. Models predicting vessel-attendance from seabird movement metrics derived from GPS, wet-dry sensors and accelerometers achieved classification rates above 90% during training. However, when tested on new individuals, 42% of their positive predictions were false-positives. Models combining environmental metrics with either GPS or GPS and wet-dry data achieved classification rates around 75% during training and generalised consistently across individuals, maintaining classification rates of 70% or above. Attendance events involving fishing (n = 482) and nonfishing vessels (n = 297) could not be reliably distinguished. Across 45 trips of radar-equipped shearwaters, the GPS and environmental model discriminated vessel-attendance in hourly bins against AIS detections (AUC = 0.85), supporting assessment of spatiotemporal attendance patterns. At the event level, only 17% of 227 predicted vessel-attendance events were supported by AIS or radar detections. However, radar detected nearby vessels during 19 predicted events lacking AIS support, highlighting the value of complementary vessel detection. This study presents a vessel-independent framework for assessing seabird-vessel interactions based solely on bird-borne data, complementing fisheries monitoring programmes, helping to identify gaps in vessel-tracking systems across poorly monitored marine regions, and informing future assessments of bycatch risk.

ecology↗

bioRxiv2026

Mosquito population control by aquatic predators: a global meta-analysis of predation efficacy by fish and odonate naiads

1- Biological control of mosquitoes using aquatic predators offers a sustainable alternative to chemical insecticides, yet the specific predator and prey functional traits that govern consumption efficacy remain poorly quantified at a global scale. 2- We conducted a global meta-analysis of 755 effect sizes across 59 studies to evaluate how predator identity (fish vs. odonate naiads), body size, dietary guilds, and prey characteristics influence consumption rates. Using multilevel models and robust publication-bias corrections, we quantified predation efficiency, expressed throughout as the consumption rate (CR, larvae predator -1 h -1 ), while accounting for methodological variations across experimental designs. The primary literature itself proved geographically skewed towards Asia (chiefly India), with Africa, the Americas, and Europe markedly under-represented. 3- Grouping predators solely by broad taxonomic identity concealed the central pattern in our data. Although naiads outperformed fish when compared directly within the same studies, this taxon-level difference was driven almost entirely by non-mosquitofish species, the least efficient predator group overall. Mosquitofish (\textit{Gambusia} spp.) and dragonfly naiads were statistically indistinguishable from one another, indicating that dietary specialisation, not taxonomic identity, is the stronger predictor of predation efficacy. Predator body size strongly and positively predicted consumption rates in naiads---driven primarily by dragonflies---but showed no significant or negative relationship in fish. 4- Methodological traits heavily structured the extreme heterogeneity observed across studies; notably, exposure time acted as a severe rate-suppressor, where prolonged assays drastically underestimated per-hour consumption rates due to satiety or handling constraints. Nevertheless, a combined model incorporating all significant ecological moderators simultaneously explained a substantial share of the between-study variance, confirming that predator-prey dynamics in these systems are highly predictable from functional traits. 5- Effective biological control cannot rely on broad taxonomic assumptions but requires evidence-based trait-matching. Management programs should prioritise body size when deploying insect predators, selecting the largest individuals within species known to consume mosquito larvae and favour insectivorous fish species over generalists. Crucially, because short-term laboratory assays artificially inflate efficacy, multi-duration assessments are essential to accurately scale up biocontrol predictions from experimental arenas to complex, real-world ecosystems.

ecology↗

bioRxiv2026

Between specialization and flexibility: how tasks and space shape behavioral profiles in ant colonies

Task allocation in eusocial insects has long been studied under the framework of division of labor, implying a relatively rigid association between individuals and tasks. However, most eusocial species lack morphological specialization, and workers regularly switch tasks as colony demands change. This raises a fundamental question: do tasks shape the behavioral profiles of workers, or does individual behavioral variation cut across task boundaries? We addressed this in a controlled laboratory study of Aphaenogaster senilis ants, comparing the behavioral profiles of four task groups (scouts, recruits, nurses, and necrophores) spatially segregated by their location within the colony setup and subsequently tested individually in four ecologically relevant contexts. This multivariate profiling, still rarely applied in ants, revealed that some tasks impose clear behavioral specialization (scouting, brood care), whereas others do not (recruitment, necrophoresis). Critically, this specialization appears in foraging-related tasks, whereas sociality does not: it varies considerably among workers, even within a single task group. Behavioral specialization, therefore, exists, but not across every dimension of behavior, and it is not a fixed property of the task. These results suggest that workers may differ in their readiness to shift roles depending on the task at hand, and this variation may in turn shape how colonies adapt to environmental change. More broadly, our results speak to a question central to collective behavior research well beyond ants: how individual variability translates into functional structure at the group level.

animal behavior and cognition↗

bioRxiv2026

Dynamic Workforce Modulation and Foraging Efficiency in Eusocial Insect Colonies

Understanding the fitness advantages conferred by eusociality remains a central challenge in behavioral ecology. One promising approach is to identify collective strategies that shift efficiency within social groups. Here, we test the hypothesis that reserve workforces in eusocial insect colonies represent an adaptive mechanism that enhances flexibility and foraging efficiency under fluctuating environmental conditions. We examine how such reserve workers modulate the departure and return rates of foragers and how these time-dependent dynamics shape the colonys overall energetic balance. By integrating an energetic-balance framework with stochastic search simulations inspired by empirical results from Aphaenogaster senilis, we quantify the energetic requirements for colony viability, incorporating energy intake, search costs, and basal metabolic demands. Our results show that as colonies grow, maintaining a positive energy balance requires a disproportionately larger relative workforce. By modulating departure and return rates over time, colonies control the synchrony of their collective search and efficiently activate or suppress their reserve workforce to scale foraging effort as needed. These findings suggest that the "lazy" or weakly engaged workers commonly observed in large colonies function as an essential reserve that stabilizes colony energetics and enhances responsiveness. Together, our results provide a functional explanation for sublinear metabolic scaling in eusocial groups and highlight workforce modulation as a key factor underlying their energetic stability and evolutionary success.

ecology↗

bioRxiv2025

Foraging Ants as Liquid Brains: Movement Heterogeneity Shapes Collective Efficiency

Liquid brains conceptualize living systems operating without central control, where collective outcomes emerge from local but dynamic interactions. Therefore, movement is expected to shape the connectivity among individuals, allowing the system to optimize its efficiency. We empirically measured ant movement behavior across large spatiotemporal scales, closely reflecting the ecology of our model species, Aphaenogaster senilis. We then incorporated this into a liquid brain framework, enabling a quantitative replication of ant foraging efficiency and their spatiotemporal dynamics. Our results highlight that a simple feedback mechanism explains the foraging patterns of this species. Indeed, such feedback is modulated by adjusting the proportion of two coexisting movement behaviors: while the recruits facilitated information transfer and food exploitation by aggregating closely to the nest, the scouts mostly bypassed this feedback, enabling the discovery of alternative food sources. These findings underscore how complex systems frameworks can benefit from empirical insights, enhancing our understanding of the mechanisms underlying collective intelligence in biological systems.

ecology↗

bioRxiv2024

Present and future suitability of invasive and urban vectors through an environmentally-driven Mosquito Reproduction Number

1Temperature and water availability significantly influence mosquito population dynamics. Weve devised a method, integrating experimental data with insights from mosquito and thermal biology, to calculate the basic reproduction number (RM) for urban mosquito species, Aedes albopictus and Aedes aegypti. RM represents the number of female mosquitoes produced by one female during her lifespan, indicating suitability for growth. Environmental conditions, including temperature, rainfall and human density influence RM by altering key mosquito life cycle traits. Validation using data from Spain and Europe confirms the approachs reliability. Our analysis suggests that temperature increases may not uniformly benefit Ae. albopictus proliferation but could boost Ae. aegypti expansion. We suggest using vector RM maps, leveraging climate and environmental data, to predict areas susceptible to invasive mosquito population growth. These maps aid in resource allocation for intervention strategies, supporting effective vector surveillance and management efforts.

ecology↗

bioRxiv2022

Multiple invasions, Wolbachia and human-aided transport drive the genetic variability of Aedes albopictus in the Iberian Peninsula

The Asian tiger mosquito, Aedes albopictus, is a highly invasive species that has been spreading rapidly throughout tropical and temperate regions worldwide since the late 1970s. On the Iberian Peninsula, it was first recorded in 2004 near Barcelona. Since then, the species has spread along the Mediterranean coast and is now colonising the Peninsulas inner territories. As with other species of the genus Aedes, the spread of the tiger mosquito has been linked to global shipping routes and road networks. In particular, the transport of adult mosquitoes by car has been shown to augment its natural spreading capacity by orders of magnitude. Much remains unknown, however, about the impact of human-mediated dispersal on the genetic variability of this species. This study aimed to ascertain the factors that have contributed to the spread and the current genetic variation of Ae. albopictus across the Iberian Peninsula, through complex dispersal mechanisms and endosymbiosis with bacteria like Wolbachia. We do so through population genetic analysis of mitochondrial (COI) and nuclear (ITS2) DNA sequences. Overall, both COI and ITS2 markers showed a lack of genetic structure among sampled regions and the presence of worldwide dominant haplotypes, suggesting a pattern of multiple introductions from abroad. We found extremely low levels of variation in COI compared to ITS2, and this lack of mitochondrial polymorphism is likely explained by high Wolbachia prevalence (79%). Multilevel models revealed that greater mosquito fluxes (estimated from commuting patterns and tiger mosquito population distribution) and spatial proximity between sampling sites were associated with lower ITS2 genetic distance, suggesting that rapid short- and medium-distance dispersal is facilitated by humans through vehicular traffic. This study highlights the significant role of human transportation in shaping the genetic attributes of Ae. albopictus and promoting regional gene flow, and underscores the need for a territorially integrated surveillance across scales of this disease-carrying mosquito. Author SummaryThe tiger mosquito, Aedes albopictus, is one of the most invasive species in the world. Native to the tropical forests of Southeast Asia, over the past 30 years it has rapidly spread throughout tropical and temperate regions of the world. Its dramatic expansion has resulted in public health concerns as a consequence of its vector competence for at least 16 viruses. Previous studies showed that Ae. albopictus spread has been facilitated by human-mediated transportation, but much remains unknown about how this has affected its genetic attributes. Here we examined the factors that contributed to shaping the current genetic constitution of Ae. albopictus in the Iberian Peninsula, where the species was first found in 2004, by combining population genetics and Bayesian modelling. We found that both mitochondrial and nuclear DNA markers showed a lack of genetic structure and the presence of worldwide dominant haplotypes, suggesting regular introductions from abroad. Mitochondrial DNA showed little genetic diversity compared to nuclear DNA, likely explained by infection with maternally transmitted bacteria of the genus Wolbachia. Our models indicated that human transportation plays a role in shaping Ae. albopictus nuclear genetic structure by means of passive dispersal of adult tiger mosquitoes through the road network.

genetics↗

bioRxiv2020

Random searchers cope with cognitive errors and uncertainty better than path planners

There is a widespread belief in ecology that the capacity of animals to orchestrate systematic and planned paths should represent a significant benefit for efficient search and exploration. Within this view, stochasticity observed in real animal trajectories is mostly understood as undesirable noise caused by internal or external effects. Far less is known, however, about the case when cognitive errors and limitations inherent to living systems are explicitly put into play. Here we compare within this context the search efficiency of (i) walkers driven by Bayesian rules generating deterministic paths, (ii) standard random walkers, and (iii) human trajectories obtained from search experiments in a soccer field and on the computer screen. Our results clearly challenge the view that deterministic paths are generally better for exploration than random strategies, as the latter are more resilient to cognitive errors. Instead, we provide numerical and experimental evidence that stochasticity would provide living organisms with a sufficient and cognitively simple exploration solution to the problem of uncertainty.

ecology↗

bioRxiv2019

Seascape genetics at its finest: dispersal patchiness within a well-connected population

Dispersal is a main determining factor of population structure and variation. In the marine habitat, well-connected populations with large numbers of reproducing individuals are common but even so population structure can exist on a small-scale. Variation in dispersal between populations or over time is often associated to both environmental and genetic variation. Nonetheless, detecting structure and dispersal variation on a fine-scale within marine populations still remains a challenge. Here we propose and use a novel approach of combining a clustering model, early-life history trait information from fish otoliths, spatial coordinates and genetic markers to detect very fine-scale dispersal patterns. We collected 1573 individuals (946 adults and 627 juveniles) of the black-faced blenny across a small-scale (2km) coastline as well as at a larger-scale area (<50kms). A total of 178 single nucleotide polymorphism markers were used to evaluate relatedness patterns within this well-connected population. Local retention and/or dispersal varied across the 2km coastline with higher frequency of SHORT-range disperser adults; representing local recruitment; towards the southwest of the area. An inverse pattern was found for juveniles, showing an increase of SHORT-range dispersers towards the northeast. This reveals a complex but not full genetic mixing and suggests oceanic/coastal circulation as the main driver of this fine-scale chaotic genetic patchiness within this otherwise homogeneous population. When focusing on the patterns within one recruitment season, we found large differences in temperatures (from approx. 17oC to 25oC) as well as pelagic larval duration (PLD) for juveniles from the beginning of the season and the end of the season. We were able to detect fine-scale differences in HIGH-range juvenile dispersers, representing distant migrants, depending on whether they were born at the beginning of the season, hence, with a longer PLD, or at the end of the reproductive season. The ability to detect such fine-scale dispersal patchiness will aid in our understanding of the underlying mechanisms of population structuring and chaotic patchiness in a wide range of species even with high potential dispersal abilities.

ecology↗