Introduction: Copepods are influenced by various climatic and oceanographic changes, including global warming, which increases the frequency of the warm phase of ENSO and contributes to reductions in their mean population body size. Objectives: This study evaluates the effects of temperature, salinity, and dissolved oxygen concentration—measured at standard depths—on the mean total length of three copepod species: Ditrichocorycaeus andrewsi, Centropages furcatus and Subeucalanus pileatus, within the pelagic environment of Gorgona Island over a nine-year period. Methods: Each year, 25 healthy female and male specimens per copepod species were selected during the cold-water season from 2013 to 2022. Vertical variability in temperature, salinity, and dissolved oxygen was analyzed. A mixed linear model was used to assess the independent effects of mean total length by sex, species, and year, while Spearman correlation confirmed associations with environmental variables. ANOVA followed by Tukey's test identified significant differences in total length among years for each species. Results: A weak positive correlation was detected between temperature and the total length of the three studied species. A linear mixed model confirmed a significant species-sex-year interaction effect. D. andrewsi and S. pileatus exhibited smaller sizes during warm periods, while C. furcatus displayed considerable variation with no clear association to thermal conditions. Conclusions: This study establishes a baseline for future research on the effects of climate change on copepod body size in the Colombian Pacific and the Eastern Tropical Pacific, and offers valuable insight into how interannual climatic variability shapes copepod populations in tropical environments, contributing to a broader understanding of climate change impacts on marine ecosystems.
The tectonic evolution of a key region in the Andean Patagonian foreland is analysed (42°-43°S). This region exposes the deepest structural level of Patagonia, preserving evidence of large-scale Palaeozoic lithospheric and upper crustal mechanical heterogeneities. The geological record involves multiple extensional and contractional deformation events of the past 200 Myr. Based on new thermochronological data, including apatite fission-track and apatite (U-Th)/He analyses, with surface and subsurface analysis, this research proposes a unified model of tectonic evolution since the onset of the Andean margin. The results reveal a complex interplay of cooling and heating episodes associated with major tectonic phases, including a Late Triassic–Early Jurassic contraction (∼215–200 Ma), Jurassic–Early Cretaceous extension (∼200–143 Ma), two pre-Paleocene contractional phases (∼143–133 Ma and ∼85–62 Ma), a Paleogene extension phase (∼62–20 Ma) and a Miocene contraction event (∼20–10 Ma). Deformation has been largely controlled by Paleozoic metamorphic inheritance and the reactivation of pre-existing structures, regardless of the prevailing tectonic regime. This has led to a lithospheric configuration that alternate between broken foreland systems during contractional events and wide-rift systems during extensional events. This research provides new insights into the long-term geodynamic evolution of intraplate settings in subduction zones with weak lithospheric conditions.
In most species, females face the risk of losing their oocytes if they remain unmated for a prolonged period. However, it remains unclear whether they have developed mechanisms to prevent the loss of fertilizable eggs according to the chances of finding a mate. We predict that virgin females will lay a lower proportion of their produced eggs when they perceive the presence of a male conspecific. We tested this prediction in the kissing bug Rhodnius prolixus, comparing the oviposition of virgin females randomly exposed to the presence of a potential mate or isolation over 10 d. We found that isolated females laid 3 times as many eggs as females exposed to the presence of a male. The dissection of females showed that both groups produced similar numbers of developed eggs, suggesting that differences in oviposition are due to changes in egg retention, rather than on egg production. We discuss the possible benefits of egg retention in virgin females, and how this process may contribute to their reproductive decision-making. Virgin female kissing bugs avoid losing their unfertilized eggs when potential mates are present. Differences in the oviposition dynamics over time were observed between females exposed to a physically inaccessible male and those kept in isolation. Isolated females laid approximately three times more eggs than those exposed to a male. The mechanisms underlying these results may be related to differential egg retention associated with female reproductive decision-making.
Evolution education seeks to help students develop scientifically adequate explanations of evolutionary adaptations. Those explanations are usually thought to entail only processes that act independently of organism agency, such as genetic mutation, inheritance, and selection. However, the role of organism agency in evolutionary outcomes has been reconsidered by evolutionary biologists in recent decades. We suggest that this agential perspective offers new potential and implications for evolution education. To explore this potential, we developed the assessment tool EvoFlex. It aims to identify students' ability to flexibly and adequately integrate the role of organism agency across cases of evolutionary adaptation. We implemented this assessment tool with preservice biology teachers, followed by interviews with a subset of respondents. Results indicate that many participants could recognise the scientifically adequate integration of organism agency across cases, despite not being specifically trained in this perspective. However, other students were also prone to disregard any role of organism agency, or they had difficulty thinking about what role it might play in evolution. Our results highlight that the agential perspective has potential in evolution education and point to several future directions in educational research and practice.
We describe a new avian ichnotaxon Gragliavipes gavenskii ichnogen. nov. ichnosp. nov. from the Miocene Vinchina Formation (La Rioja Province, Argentina) attributed to the Ignotornidae ichnofamily, thus constituting the first Cenozoic record from South America. These are semipalmate tetradactyl footprints with a very short interdigital web more developed between digits III and IV. Digits II, III and IV point forward, while digit I is posteromedially oriented and connected by a tarsal-metatarsal joint. It differs from other ichnotaxa within Ignotornidae due to the presence of an interdigital web, digit I being 50% of the total footprint length, an average divarication angle of 123 degrees, and average stride and pace lengths that are 30% to 50% smaller than those of other ichnospecies within the ichnogenus. The estimated body mass of the trackmaker is approximately 521 gr. The backward position of digit I, its relative length compared to the footprint length and size of the animal, suggests that the trackmaker was most likely a small ibis (Threskiornithidae). We include an ichnotaxonomic review of the Cretaceous and Cenozoic avian ichnofamilies to achieve a more simplified supra-generic systematics for avian footprints. The new ichnotaxon extends the stratigraphic and spatial range of Ignotornidae within the Cenozoic and to South America.
