Wing reduction and body size variation along a steep elevation gradient: a case study with Magellanic sub-Antarctic mayflies and stoneflies

Introduction: Ecogeographical patterns in body size have been described across a wide range of vertebrate species. However, insects have shown inconsistent patterns in studies to date. Aquatic insects, particularly those from remote regions, have barely been explored. Methods: The Magellanic sub-Antarctic ecoregion offers an ideal natural laboratory with near pristine environments, limiting the potential influence of confounding variables. In this study, we evaluated the influence of elevation on body and wing size and aspect ratio patterns for 10 species of mayfly (Ephemeroptera) and stonefly (Plecoptera) along a steep coastal elevation gradient (~0–600 m a.s.l.). Results: We detected significant relationships between altitude and morphological features for the studied species. Additionally, we found that in females, morphological changes were slightly more pronounced than in males, probably due to their role as dispersers. While body size showed an increase along the elevation gradient, there was a notable decrease in some species' wing length over a relatively short geographic distance. Discussion: Our data suggest that morphological plasticity might be promoted in response to the harsh environmental conditions that typify the steep coastal Magellanic sub-Antarctic mountain ranges

Freshwater macroinvertebrates from Yendegaia National Park, Chile: Tackling knowledge biodiversity gaps in the Cape Horn Biosphere Reserve

The Yendegaia National Park, located to the south of Tierra del Fuego and at the eastern margin of the Darwin Mountain Range, forms part of the Cape Horn Biosphere Reserve (CHBR) and lies in the Magellanic sub-Antarctic ecoregion. This national park in the extreme south of Chile comprises an extensive valley surrounded by mountain ranges that give rise to glacial and rain or snow-melt streams. The present study provides the first inventory of freshwater macroinvertebrates within the park, further comparing the species composition of three rivers with contrasting riparian vegetation. One river has a riparian vegetation dominated by Coihüe de Magallanes (Nothofagus betuloides), an evergreen species. The river with riparian vegetation dominated by lenga presented a significantly higher diversity of macroinvertebrates than in the rivers with riparian vegetation dominated by ñirre and coihüe. The community composition of macroinvertebrates presents some affinities with that reported for other areas within the reserve with similar vegetational composition, such as Navarino Island or the Alberto de Agostini National Park. The influence of riparian vegetation and other environmental variables must be studied through other approaches. In this way, the need for studies that complement the inventory presented here emerges, contributing to a characterization that allows the evaluation of ecological patterns of aquatic macroinvertebrates. In this way, it will be possible to identify generalities and singularities of the freshwater biological communities and their environmental relationships in the southern tip of Chile

Altitudinal gradients in Magellanic sub-Antarctic lagoons: the effect of elevation on freshwater macroinvertebrate diversity and distribution.

Background. The study of altitudinal gradients provides insights about species diversity, distribution patterns and related drivers. The Magellanic sub-Antarctic ecoregion has a steep elevational gradient, peaking at around 1,000 m a.s.l., and marked changes in temperature and landscape composition can be observed over relatively short distances. Methods. This study assessed freshwater macroinvertebrate diversity associated with lakes and ponds along the altitudinal gradient of a Magellanic sub-Antarctic watershed. Results. A monotonic decline in species richness was observed with increasing elevation, with simpler and more even community composition at higher altitude. This pattern differs from the mid-peak trend found in streams of the same watershed. Functional feeding group structure also diminished with increasing elevation. Discussion. The study provides a descriptive baseline of macroinvertebrate community structure associated with lentic freshwater ecosystems in the Magellanic sub-Antarctic ecoregion, and confirms that elevation has substantial effects on community structure, function and environmental features, even in these relatively low elevation mountain ranges. The harsh environmental conditions of this ecoregion increase freshwater macroinvertebrate development time, as well as decreasing habitat availability and food supply, supporting simple but well adapted communities. In conjunction with previous research, this study provides a watershed-scale platform of information underpinning future long-term research in the region

Primer registro de Vespula vulgaris (Linnaeus 1758) (Hymenoptera: Vespidae) en la isla Navarino, Chile

The common wasp Vespula vulgaris (Linnaeus 1758) is an introduced species in the Southern Hemisphere that has been reported in Australia, New Zealand, Tasmania, Argentina and South-central Chile. This report documents the presence of V. vulgaris on Navarino Island, Cape Horn Biosphere Reserve, Southern Chile.La avispa común Vespula vulgaris (Linnaeus 1758) es una especie introducida en el Hemisferio Sur que ha sido registrada en Australia, Nueva Zelanda, Tasmania, Argentina y Chile central. Este trabajo documenta la presencia de V. vulgaris en la isla Navarino, Reserva de la Biósfera Cabo de Hornos, sur de Chile

Memorias de investigación: Feria de Semilleros y Jornadas de Investigación de uniminuto, Seccional Antioquia - Chocó.

Feria de Semilleros y Jornadas de Investigación de uniminuto, Seccional Antioquia - Chocó.Esta publicación busca divulgar investigaciones y producción académica en diferentes disciplinas, realizadas por estudiantes y docentes de UNIMINUTO Seccional Antioquia – Chocó, así como dar a conocer los semilleros de investigación que participaron en la V Feria de Semilleros, con el fin de visibilizar el trabajo que realiza el Centro de Investigación para el Desarrollo de UNIMINUTO Bello —CIDUB—, con respecto a debates académicos y espacios de interlocución. Igualmente, permite que la comunidad educativa conozca los temas de investigación y las discusiones que se están dando entre los semilleros y grupos de investigación, para así buscar puntos de encuentro y sinergias entre los investigadores. Adicionalmente, el texto se convierte en una invitación para que se vinculen otros investigadores, docentes, estudiantes e incluso otras instituciones a los procesos investigativos coordinados desde el CIDUB

Memorias de investigación: Feria de Semilleros y Jornadas de Investigación de uniminuto, Seccional Antioquia - Chocó.

Feria de Semilleros y Jornadas de Investigación de uniminuto, Seccional Antioquia - Chocó.Esta publicación busca divulgar investigaciones y producción académica en diferentes disciplinas, realizadas por estudiantes y docentes de UNIMINUTO Seccional Antioquia – Chocó, así como dar a conocer los semilleros de investigación que participaron en la V Feria de Semilleros, con el fin de visibilizar el trabajo que realiza el Centro de Investigación para el Desarrollo de UNIMINUTO Bello —CIDUB—, con respecto a debates académicos y espacios de interlocución. Igualmente, permite que la comunidad educativa conozca los temas de investigación y las discusiones que se están dando entre los semilleros y grupos de investigación, para así buscar puntos de encuentro y sinergias entre los investigadores. Adicionalmente, el texto se convierte en una invitación para que se vinculen otros investigadores, docentes, estudiantes e incluso otras instituciones a los procesos investigativos coordinados desde el CIDUB

Ecological features of exotic Vespula wasps (Hymenoptera: Vespidae) invading the southernmost UNESCO Biosphere Reserve

Invasive alien species may cause substantial changes and damaging impacts. Here, we document the current distribution and ecological interactions with native biota of relatively recently introduced wasps, Vespula vulgaris and V. germanica, in the southern part of the Cape Horn Biosphere Reserve (CHBR) in southern Chile. We conducted field studies in four different habitats on Navarino Island: evergreen, deciduous and mixed forests, and shrublands. The spread of V. vulgaris throughout the island has led to it occupying suitable habitats in both urban and rural settings, while V. germanica has not been observed in the last 2 years. The presence of V. vulgaris in remote areas of the CHBR is likely the result of human-mediated movement through the channels within the reserve. The composition of foraged items was different in each of the four studied habitats, yet strongly linked to the resources of each, indicating the inherent ability of V. vulgaris to exploit available resources efficiently. V. vulgaris mainly forages berries from shrubs, and preys on a variety of arthropods, particularly hoverflies, craneflies and lepidoptera larvae. The lack of natural competitors and availability of multiple resources has allowed V. vulgaris to rapidly become a common pest in urban and rural settings in the southern extremity of South America. While we consider that eradication would now be impossible, population control at local scales may still be possible with proper planning and long-term management. Our data provide a baseline for management planning, and we strongly recommend social engagement and dialog with relevant governmental institutions to achieve this challenging task

First record of Vespula vulgaris (Linnaeus 1758) (Hymenoptera: Vespidae); on Navarino Island, Chile

This article documents the presence of the common wasp V. vulgaris on Navarino Island, Cape Horn Biosphere Reserve, Southern Chile

Ancient diversification in extreme environments: exploring the historical biogeography of the Antarctic winged midge Parochlus steinenii (Diptera: Chironomidae)

Peer reviewed: TrueAcknowledgements: Maritime Antarctic and South Georgia material was collected under permits from INACH and the Government of South Georgia and the South Sandwich Islands. We thank the Captain, officers, crew and expedition staff of Commandant Charcot and, in particular, Science Officer Geoffroy Dekersauson, from Ponant expedition LEG CC120323. We thank Javier Rendoll Cárcamo, Simón Castillo, Ramiro Bustamante, Gilliam Graham and Gonzalo Arriagada for their help in the different stages of this project.The terrestrial fauna of Antarctica consists of a limited number of species, notably insects, small crustaceans and other micro-invertebrates. Over long periods of evolutionary isolation, these organisms have developed varying degrees of tolerance to multifaceted environmental stresses. Recent molecular biogeographical research highlights the enduring persistence of much of Antarctica’s current terrestrial fauna, with estimates spanning from hundreds of thousands to millions of years. Parochlus steinenii, commonly known as the Antarctic winged midge, stands out as one of the only two insect species native to Antarctica. Distributed across three biogeographic regions, southern South America and the Falkland/Malvinas Islands, sub-Antarctic South Georgia and the Maritime Antarctic South Shetland Islands, this midge raises questions about the temporal isolation of its populations and their divergence. Employing mitochondrial and nuclear genetic markers, we conducted phylogeographic and demographic analyses on 151 individuals of P. steinenii obtained across the three main biogeographic regions including the Magellanic sub-Antarctic Ecoregion (MSE) of southern South America, the sub-Antarctic Island of South Georgia (SG) and the South Shetland Islands (SSI) within the Maritime Antarctic (MA). Our data support the diversification of P. steinenii during the mid-Pleistocene around 1.46 Mya. This period included a branching event between a clade containing only specimens from the MSE and a clade containing individuals from a broader range of locations including the SSI and SG. Based on intraspecific phylogeographic and demographic inferences, we detected strong evolutionary divergence between the three main biogeographic regions. We also detected a signal of population growth during the deglaciation process in SSI and SG, contrary to the pattern seen in the MSE. The different demographic and phylogeographic histories between the sampled biogeographic regions could result from the MA and SG experiencing a strong genetic bottleneck due to a reduction in population size during the Last Glacial Maximum, while the MSE maintained a significant effective population size. The high level of divergence detected between individuals from the MSE and the remaining biogeographic regions supports the hypothesis of a speciation process taking place in P. steinenii.</jats:p