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Section: Ecotoxicology & Environmental Chemistry ; Topics: Environmental sciences

Effects of dibutyl phthalate (DBP) on life history traits and population dynamics of Daphnia magna: comparison of two exposure regimes

Ohanessian, Jérémie; Prud’homme, Sophie Martine; Franklin, Ellis; Kitzinger, Géraldine; Lorgeoux, Catherine; Billoir, Elise; Felten, Vincent

10.24072/pcjournal.586 - Peer Community Journal, Volume 5 (2025), article no. e85
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Phthalates are chemical products used as additives in the synthesis of plastics to increase their flexibility and resistance. Among the most frequently detected phthalates in the environment is dibutyl phthalate (DBP). Although ubiquitous in freshwater environments at concentrations in the ng/L to µg/L range, studies on the effects of DBP on Daphnia magna have overlooked the potential effects of exposure at low concentrations (µg/L order) and without solvent. Our work focuses on the chronic effects of DBP on life history traits (survival, growth, reproduction) in the freshwater model species, D. magna (Crustacea). Organisms were exposed to two exposure regimes: from the beginning of embryonic development or from the adult stage, at the third brood, when most of the energy investment in growth is complete. The results obtained show that the DBP exposure regime is an essential parameter in the effects on D. magna life history traits. While no significant response was observed in organisms exposed at the adult stage, disturbances to survival, growth and reproduction were observed at concentrations as low as the µg/L range in organisms exposed at the beginning of embryonic development. The results also demonstrated that exposure to a concentration gradient of DBP results in different dose-dependent response typologies, depending on the life history traits measured. For survival, the dose-response relationship was non-monotonic, with greater juvenile mortality at intermediate concentrations (100, 280 and 500 µg/L) than at higher concentrations (1000 and 2000 µg/L). For effects on growth and reproduction, the responses followed classic monotonic dose-response relationships with low sensitivities. At the end of the experiment, the EC10-25d values were 1.01 µg/L for reproduction and 79.22 µg/L for growth. However, when calculated at earlier timepoints, the EC10-4d and the EC10-7d for growth were 0.25 µg/L and 1.16 µg/L. Furthermore, projecting these results to the population level suggests that exposure to DBP from early embryonic development leads to a decrease in growth rate and a change in population structure.
Section: Archaeology ; Topics: Archaeology, Statistics

fabryka. A web application for easily analysing & exploring the fabric of archaeological assemblages

Thomas, Marc

10.24072/pcjournal.611 - Peer Community Journal, Volume 5 (2025), article no. e84
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This article presents fabryka 1.1, an open access R shiny web application dedicated to the fabric analysis of archaeological or geological assemblages. The fabric is a statistic made of the orientation and dip of elongated particles and archaeological objects. It provides information about the nature of the geological processes involved in the formation of the deposits and their impact on the preservation of the archaeological assemblages. This statistical analysis is not easily accessible to non-specialists and is particularly time-consuming, sometimes requiring the use of several software, some of which are chargeable. fabryka uses classical analytical procedures (Benn, rose, Schmidt and Woodcock diagrams and statistical tests on orientations) for analysing the fabrics of objects and includes a spatial method. New statistical methods and new ways of exploration are proposed in the application and in this present article. You can use fabryka by following this link https://marchaeologist.shinyapps.io/fabryka/ or by launching the application in Rstudio thanks to its script. The fabryka application files, made in R (R Core Team 2025) by using the R package shiny (Chang et al. 2024), and this article, written in rmarkdown (Allaire et al. 2014; Xie, Allaire, and Grolemund 2018; Xie, Dervieux, and Riederer 2020), are both available online in a public github repository (https://github.com/marchaeologist/fabryka/tree/main).
Section: Ecology ; Topics: Ecology, Evolution

Behavioral flexibility is related to exploration, but not boldness, persistence or motor diversity

McCune, Kelsey B.; Lukas, Dieter; MacPherson, Maggie P.; Logan, Corina J.

10.24072/pcjournal.593 - Peer Community Journal, Volume 5 (2025), article no. e83
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Behavioral flexibility, the ability to change behavior when circumstances change based on learning from previous experience, is thought to play an important role in a species' ability to successfully adapt to new environments and expand its geographic range. However, behavioral flexibility is rarely directly tested at the individual level. This limits our ability to determine how it relates to other traits, such as exploration or persistence, that might also influence individual responses to novel circumstances. Without this information, we lack the power to predict which traits facilitate a species' ability to adapt behavior to new environments. We use great-tailed grackles (a bird species; hereafter “grackles”) as a model to investigate this question because they have rapidly expanded their range into North America over the past 140 years. We evaluated whether grackle behavioral flexibility (measured as color reversal learning) correlated with individual differences in the exploration of new environments and novel objects, boldness towards known and novel threats, as well as persistence and motor diversity in accessing a novel food source. We determined that exploration of a novel environment across two time points and persistence when interacting with several different novel apparatuses were repeatable in individual grackles. There was no relationship between exploration or persistence and the two components of flexibility - the rate of learning to prefer a color option in the reversal learning task, and the rate of deviating from a preferred option. However, grackles that underwent serial reversal training to experimentally increase behavioral flexibility were more exploratory in that they spent more time in close proximity to the novel environment relative to control individuals. This indicates that, the more an individual investigated a novel apparatus, the more it was able to potentially learn and update its knowledge of current reward contingencies to adapt behavior accordingly. Our findings improve our understanding of the traits that are linked with flexibility in a highly adaptable species. We highlight the importance of using multiple different methods for measuring boldness and exploration to evaluate consistency of performance and therefore the methodological validity. We also show a link between exploration and behavioral flexibility that could facilitate adaptation to novel environmental changes.
Section: Ecology ; Topics: Ecology, Evolution

Reduced levels of relatedness indicate that great-tailed grackles disperse further at the edge of their range

Lukas, Dieter; Blackwell, Aaron D.; Edrisi, Maryam; Hardy, Kristin; LeGrande, Christa; Marfori, Zara; McCune, Kelsey B.; Sevchik, August; Smith, Caroline; Logan, Corina J.

10.24072/pcjournal.591 - Peer Community Journal, Volume 5 (2025), article no. e82
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It is generally thought that behavioral flexibility, the ability to change behavior when circumstances change, plays an important role in the ability of a species to rapidly expand their geographic range. To expand into new areas, individuals might specifically show flexibility in dispersal behavior, their movement away from their parents to where they themselves reproduce. Great-tailed grackles (Quiscalus mexicanus) are a bird species that is rapidly expanding its geographic range and are behaviorally flexible. Here, we infer dispersal rates in wild-caught grackles from two populations across their range (an older population in the middle of the northern expansion front in Arizona nearer the core of their original range versus a young population on the northern edge of the expansion front in California) to investigate whether grackles show flexibility in their dispersal behavior between these two populations. Based on genetic relatedness, we observe no closely related pairs of individuals at the edge, suggesting that individuals of both sexes disperse further from their parents and siblings in this population than in the population nearer the core. Our analyses also suggest that, in both populations, females generally move shorter distances from where they hatched than males. These results elucidate that the rapid geographic range expansion of great-tailed grackles is associated with individuals, in particular females, differentially expressing dispersal behaviors.

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The network image was drawn by Martin Grandjean: A force-based network visualization CC BY-SA