Hot males: thermal biology of males and females during coercive mating in water striders Gerris lacustris.

Sexual conflict theory predicts that males that adopt coercive mating strategies impose costs to females during copulation. Nevertheless, conflicting mating strategies may also affect males, although such effects on males are often neglected in the literature. Here, we seek to understand whether male water striders (Gerris lacustris) experience higher body temperatures than females during coercive mating behavior. We we explored whether the water temperature affected male and female body temperature differently, considering that water contact by females might serve as a thermal regulator. We built generalized linear mixed models considering the male and female temperature as the dependent variables. Air temperature (as a proxy for solar radiation), water temperature, and sex were used as predictor variables. Our results suggest that males are warmer than females, and despite females coming into contact with water during skimming, this contact does not significantly contribute to lowering their body temperature or improving thermoregulation under the observed conditions. These findings provide novel insights into the thermal biology of water striders. Future studies should focus on addressing whether warmer temperatures confer some advantages to males, such as increased mobility and better ability to hold onto females or impose physiological constraints and fitness costs.

Color lightness of velvet ants (Hymenoptera: Mutillidae) follows an environmental gradient.

Color traits are highly influenced by environmental conditions along the distributional range of many species. Studies on the variation of animal coloration across different geographic gradients are, therefore, fundamental for a better understanding of the ecological and evolutionary processes that shape color variation. Here, we address whether color lightness in velvet ants (Hymenoptera: Mutillidae) responds to latitudinal gradients and bioclimatic variations, testing three ecogeographic rules: The Thermal melanism hypothesis; the Photoprotection hypothesis; and Gloger's rule. We test these hypotheses across the New World. We used photographs of 482 specimens (n = 142 species) of female mutillid wasps and extracted data on color lightness (V). We analyzed whether variation in color is determined by bioclimatic factors, using Phylogenetic Generalized Least Square analysis. Our explanatory variables were temperature, ultraviolet radiation, humidity, and forest indicators. Our results were consistent with the Photoprotection hypothesis and Gloger's rule. Species with darker coloration occupied habitats with more vegetation, higher humidity, and UV-B radiation. However, our results refute one of the initial hypotheses suggesting that mutillids do not respond to the predictions of the Thermal melanism hypothesis. The results presented here provide the first evidence that abiotic components of the environment can act as ecological filters and as selective forces driving the body coloration of velvet ants. Finally, we suggest that studies using animals with melanin-based colors as a model for mimetic and aposematic coloration hypotheses consider that this coloration may also be under the influence of climatic factors and not only predators.

Vector species richness predicts local mortality rates from Chagas disease.

Vector species richness may drive the prevalence of vector-borne diseases by influencing pathogen transmission rates. The dilution effect hypothesis predicts that higher biodiversity reduces disease prevalence, but with inconclusive evidence. In contrast, the amplification effect hypothesis suggests that higher vector diversity may result in greater disease transmission by increasing and diversifying the transmission pathways. The relationship between vector diversity and pathogen transmission remains unclear and requires further study. Chagas disease is a vector-borne disease most prevalent in Brazil and transmitted by multiple species of insect vectors of the subfamily Triatominae, yet the drivers of spatial variation in its impact on human populations remain unresolved. We tested whether triatomine species richness, latitude, bioclimatic variables, human host population density, and socioeconomic variables predict Chagas disease mortality rates across over 5000 spatial grid cells covering all of Brazil. Results show that species richness of triatomine vectors is a good predictor of mortality rates caused by Chagas disease, which supports the amplification effect hypothesis. Vector richness and the impact of Chagas disease may also be driven by latitudinal components of climate and human socioeconomic factors. We provide evidence that vector diversity is a strong predictor of disease prevalence and give support to the amplification effect hypothesis.

Taxonomic Contributions on Macrogynoplax Enderlein and Enderleina Jewett (Plecoptera: Perlidae) from Brazil, Including a New Species Supported by Molecular and Morphological Data.

Stoneflies (Plecoptera) are aquatic insects widely used in ecological and monitoring studies as indicators of environmental quality due to their high sensitivity to pollution. Among Brazilian Plecoptera, Perlidae is the most diverse family, with four genera (Anacroneuria Klapálek 1909, Enderleina Jewett 1960, Kempnyia Klapálek 1914, and Macrogynoplax Enderlein 1909) and about 150 species. Herein, based on data from the barcode region of the mitochondrial cytochrome c oxidase subunit I (COI) gene and morphological characters, we studied specimens of Enderleina and Macrogynoplax, mainly from the Brazilian Savanna. Our alignment with a total length of 608 base pairs included 23 COI sequences, of which 10 are new and 13 were obtained from GenBank. The sequences and congruence of the obtained species clusters were analyzed using neighbor joining. As a result, we describe a new species of Enderleina, the first of this genus in the Brazilian Savanna, and update the geographic distribution of some Macrogynoplax species. A new record was included for Macrogynoplax veneranda Froehlich 1984 in São Paulo state and the first record of M. yupanqui Stark 1996 in Brazil was also included. First records were made for Macrogynoplax matogrossensis Bispo and Neves 2005 and a Macrogynoplax specimen in Goiás and Bahia states, respectively. Consequently, we expanded the distribution of the genus in the Brazilian Savanna and Atlantic Forest. In addition, we provide observations on the morphological differences found among these species, discuss about the distribution of the genera, present molecular data discussing their contributions to the knowledge of the genus, and comment on the recommendations for future research considering a scenario of integrative approaches. Lastly, we present a key to identify the adult males of Enderleina.

Scorpion envenomation in the neotropical savannah: Environmental predictors and years of lost life.

Scorpion stings envenomation (SSE) is a growing medical concern in Brazil, particularly in the state of Minas Gerais, which has recorded a significant number of incidents. This study aimed to investigate the potential predictors of scorpion sting incidence and evaluate the cost-effectiveness of interventions in Minas Gerais. Generalized Estimating Equations (GEE) models were constructed using socioeconomic and environmental variables as predictors and scorpion sting incidence as the response variable. The analysis revealed that mean annual temperature and major land use type were significant predictors of scorpion sting incidence, while precipitation and socioeconomic variables showed no relationship with incidence. The total number of cases and annual incidence of scorpion stings overlapped with regions experiencing higher forest conversion and agricultural land use, as well as higher temperatures. The estimated Disability-Adjusted Life Years (DALY) for scorpion sting incidents in Minas Gerais was substantial, indicating the need for effective prevention and treatment measures. The cost per DALY averted varied among municipalities, with some requiring minimal investment while others needing significant funding to address the scorpion risk. Mean annual temperature emerged as the main risk factor for scorpion stings, contributing to increased costs associated with antivenom treatment. These findings highlight the importance of considering environmental factors and implementing targeted interventions to mitigate scorpion sting incidents and reduce associated morbidity and mortality.

Certain species of Plecoptera from the headwater springs of National Integration River (São Francisco), Brazil.

Specimens of Anacroneuria Klapálek 1909 (Plecoptera: Perlidae) and Tupiperla Froehlich 1969 (Plecoptera: Gripopterygidae) from the headwater springs of the National Integration River (São Francisco River), Serra da Canastra National Park, in Minas Gerais State, of southeastern Brazil, were studied. A new species, Anacroneuria saofrancisco n. sp. is described and the descriptions of the nymph and the female of A. saofrancisco are also presented.