A natural history account of Megalomyrmex ayri Brandão, 1990 (Hymenoptera: Formicidae: Myrmicinae)

L. P. Prado, R. R. Silva, C. R. F. Brandão, M. S. C. Morini & R. M. M. Adams. Insect. Soc. (2021). https://doi.org/10.1007/s00040-021-00840-6

Abstract

The ant genus Megalomyrmex Forel, 1885, has 45 valid species and is spread across the entire Neotropical region. Megalomyrmex species have been studied for decades and there are many rich natural history accounts that describe various details, including symbionts and unusual reproductive strategies. Natural history traits such as lifestyle have been used to help delimit Megalomyrmex species and the four species groups (i.e., Leoninus, Modestus, Pusillus, and Silvestrii), but recent findings suggest well-sampled comparative studies coupled with revisionary taxonomy are still needed. We report observations of the natural history of the Megalomyrmex ayri Brandão, 1990, regarding diet, nesting habits, abundance, distribution, and reproductive strategy. The sampling was conducted in a Terra Firme Forest, in the municipality of Itaituba, state of Pará, in the Tapajós River region of the Brazilian Amazon. Our observations reduce knowledge gaps about the lesser known Megalomyrmex species, and are essential for an understanding of the evolutionary history of the genus.

Of olives and carp: interactive effects of an aquatic and a terrestrial invader on a stream-riparian ecosystem

KALEB K. HEINRICH, COLDEN V. BAXTER, ALEX T. C. BELL, AND JAMES M. HOOD. 2021. Ecosphere 12(10):e03789. 10.1002/ecs2.3789

Abstract

Multiple invasive species may interact, influencing one another and generating synergistic effects on food webs and ecosystem processes. We investigated the interaction between two non-native species widespread in the western USA: common carp (Cyprinus carpio) and Russian olive (Elaeagnus angustifolia), an invasive riparian tree associated with di-nitrogen fixation. Deep Creek, Idaho, was an International Biological Program site in the early 1970s; at that time, carp were rare and Russian olive was absent. Subsequently, Russian olive was introduced and established a dense stand, increasing allochthonous inputs and nitrogen-rich benthic organic matter. Since 1971, carp density has increased ~4× (an increase our bioenergetic analysis suggests could not have been sustained in the absence of Russian olive). Carp gut contents in 2013–2014 revealed, on average, ~40% olives, and, similarly, stable isotope analyses revealed ~58% of carp tissues were derived from olives. A small-scale, short-term experimental exclusion of these subsidized carp caused ~3× increases in macrophytes and chlorophyll-a, suggesting they may limit algae and macrophyte biomass. Moreover, carp that consumed olives excreted more nitrogen (~2× more ammonium, ~2× more total dissolved nitrogen, and ~3× more total nitrogen) compared to those that had not, which may amplify recycling and export from streams invaded by both species. This scenario is characteristic of an “invasional meltdown,” with attendant changes in food webs and ecosystem processes.

Rank- and sex-specific differences in the neuroendocrine regulation of glucocorticoids in a wild group-living fish

Brett M. Culbert, Isaac Y. Ligocki, Matthew G. Salena, Marian Y.L. Wong, Ian M.Hamilton, Nadia Aubin-Horth, Nicholas J.Bernier, Sigal Balshine. Hormones and Behavior. Volume 136, November 2021, 105079. https://doi.org/10.1016/j.yhbeh.2021.105079

Abstract

Individuals that live in groups experience different challenges based on their social rank and sex. Glucocorticoids have a well-established role in coordinating responses to challenges and glucocorticoid levels often vary between ranks and sexes. However, the neuroendocrine mechanisms regulating glucocorticoid dynamics in wild groups are poorly understood, making it difficult to determine the functional consequences of differences in glucocorticoid levels. Therefore, we observed wild social groups of a cooperatively breeding fish (Neolamprologus pulcher) and evaluated how scale cortisol content (an emerging method to evaluate cortisol dynamics in fishes) and expression of glucocorticoid-related genes varied across group members. Scale cortisol was detectable in ~50% of dominant males (7/17) and females (7/15)—but not in any subordinates (0/16)—suggesting that glucocorticoid levels were higher in dominants. However, the apparent behavioural and neuroendocrine factors regulating cortisol levels varied between dominant sexes. In dominant females, higher cortisol was associated with greater rates of territory defense and increased expression of corticotropin-releasing factor in the preoptic and hypothalamic regions of the brain, but these patterns were not observed in dominant males. Additionally, transcriptional differences in the liver suggest that dominant sexes may use different mechanisms to cope with elevated cortisol levels. While dominant females appeared to reduce the relative sensitivity of their liver to cortisol (fewer corticosteroid receptor transcripts), dominant males appeared to increase hepatic cortisol breakdown (more catabolic enzyme transcripts). Overall, our results offer valuable insights on the mechanisms regulating rank- and sex-based glucocorticoid dynamics, as well as the potential functional outcomes of these differences.

Season and Discharge Predict Downstream Emigration Rates for Reservoir Sport Fish Populations

Keith D. Shane,Kevin S. Page,Jeremy J. Pritt,Joseph D. Conroy,Elizabeth A. Marschall. 2021. North American Journal of Fisheries Management. https://doi.org/10.1002/nafm.10700

Abstract

Given the importance of reservoir fisheries and the investments made by fisheries management agencies to create and maintain these fisheries, the loss of reservoir-stocked fish through downstream emigration warrants action to be taken to understand and prevent it. The factors driving emigration of reservoir fish and the measurable effects of emigration on fish population dynamics are not well understood. In this study, we sought to understand the seasonal emigration patterns of two popular sport fish, saugeye (female Walleye Sander vitreus × male Sauger Sander canadensis) and Muskellunge Esox masquinongy, and determine if their annual declines in abundance were correlated with predicted annual emigration rates. We modeled daily emigration probabilities of saugeye and Muskellunge from PIT tag data collected in the dam spillway of an Ohio reservoir. Using data on discharge from previous years, these models were used to estimate annual emigration rates, which were regressed against historical catch data to test whether emigration explained annual cohort declines. Our models showed that downstream emigration from the reservoir occurred primarily during spring for both species, especially during periods of high reservoir discharge. All saugeye and nearly all Muskellunge emigrants were adults, with 13% of tagged adult saugeye and 17% of tagged adult Muskellunge emigrating. Our models predicted historical annual emigration losses (across all age-classes) as high as 24% for saugeye and 8.6% for Muskellunge. Furthermore, historical annual emigration rates were negatively related to catch rates for both species. These results illustrate that, depending on flow regime and seasonal effects on fish movements, emigration can have measurable effects on reservoir sport fish populations. As such, it is important to understand the factors driving downstream migration and use this understanding to inform decisions on potential mitigation of emigration as well as fish stocking decisions.

Review of the genus Sessiluncus (Acari: Mesostigmata: Ologamasidae), description of male and redescription of female of Sessiluncus aegypticus, and notes on some morphological characters of the genus

SHAHROOZ KAZEMI, ABDELRADY KORASHY NASR, MAHMOUD MOHAMED RAMADAN, HANS KLOMPEN. 2021. Zootaxa, 5061(2), 271–299. https://doi.org/10.11646/zootaxa.5061.2.3

Abstract

The concept of the genus Sessiluncus G. Canestrini is reviewed, based on a review of the literature and examination of some described and undescribed species. An updated diagnosis of the genus is presented. Valid species of Sessiluncus and their most diagnostic morphological characters are listed. The male of S. aegypticus Nasr & Afifi, 1986 is described for the first time based on specimens collected in Egypt, and the female is redescribed from specimens collected in Egypt and Iran. Sessiluncus oculatus Vitzthum, 1935 is reported from Panama, and supplementary information on S. hungaricus Karg, 1964 and S. oculatus is presented. The labrum, paralabrum and paralabral stylus of S. aegpticus are also described. The idiosomal adenotaxy and poroidotaxy of the genus are described and discussed.

On the Biological Diversity of Ant Alkaloids

Eduardo Gonçalves Paterson Fox and Rachelle M.M. Adams. Annual Review of Entomology 2022 67:1. https://doi.org/10.1146/annurev-ento-072821-063525

Abstract

Ants have outstanding capacity to mediate inter- and intraspecific interactions by producing structurally diverse metabolites from numerous secretory glands. Since Murray Blum's pioneering studies dating from the 1950s, there has been a growing interest in arthropod toxins as natural products. Over a dozen different alkaloid classes have been reported from approximately 40 ant genera in five subfamilies, with peak diversity within the Myrmicinae tribe Solenopsidini. Most ant alkaloids function as venom, but some derive from other glands with alternative functions. They are used in defense (e.g., alarm, repellants) or offense (e.g., toxins) but also serve as antimicrobials and pheromones. We provide an overview of ant alkaloid diversity and function with an evolutionary perspective. We conclude that more directed integrative research is needed. We suggest that comparative phylogenetics will illuminate compound diversification, while molecular approaches will elucidate genetic origins. Biological context, informed by natural history, remains critical not only for research about focal species, but also to guide applied research.

Individual Variability in Bothrops atrox Snakes Collected from Different Habitats in the Brazilian Amazon: New Findings on Venom Composition and Functionality

Leijane F. Sousa, Matthew L. Holding, Tiago H. M. Del-Rei, Marisa M. T. Rocha, Rosa H. V. Mourão, Hipócrates M. Chalkidis, Benedito Prezoto, H. Lisle Gibbs, and Ana M. Moura-da-Silva. Toxins 2021, 13(11), 814; https://doi.org/10.3390/toxins13110814

Abstract

Differences in snake venom composition occur across all taxonomic levels and it has been argued that this variation represents an adaptation that has evolved to facilitate the capture and digestion of prey and evasion of predators. Bothrops atrox is a terrestrial pitviper that is distributed across the Amazon region, where it occupies different habitats. Using statistical analyses and functional assays that incorporate individual variation, we analyzed the individual venom variability in B. atrox snakes from four different habitats (forest, pasture, degraded area, and floodplain) in and around the Amazon River in Brazil. We observed venom differentiation between spatially distinct B. atrox individuals from the different habitats, with venom variation due to both common (high abundance) and rare (low abundance) proteins. Moreover, differences in the composition of the venoms resulted in individual variability in functionality and heterogeneity in the lethality to mammals and birds, particularly among the floodplain snakes. Taken together, the data obtained from individual venoms of B. atrox snakes, captured in different habitats from the Brazilian Amazon, support the hypothesis that the differential distribution of protein isoforms results in functional distinctiveness and the ability of snakes with different venoms to have variable toxic effects on different prey.

Information Seeking and Risk Reduction Intentions in Response to Environmental Threat Messages: The Role of Message Processing

Elisabeth Bigsby, Shelly R. Hovick, Naomi Q. P. Tan, Sarah N. Thomas, Sam R. Wilson. 2021. Risk Analysis. https://doi.org/10.1111/risa.13857

Abstract

Communicating complex information about environmental health risks in a single message is impossible. Thus, message designers hope that risk messages encourage people to think more about the message and risks, look for more information, and ultimately make behavior changes. The presentation of information about environmental risks using threat appeals is a common message design strategy thought to increase message engagement and influence attitudes, information seeking, and risk reduction behaviors. We compared lower threat messages, which did not include explicit statements about susceptibility and severity of a risk, to higher threat messages, which did. We combined predictions from the extended parallel process model with dual-process theories of persuasion to examine whether people respond to these types of messages differently. In an online experiment, participants (N = 892) were randomly assigned to a message condition (higher or lower threat) and topic condition (arsenic, bisphenol A, or volatile organic compounds). Overall, participants exposed to higher threat messages (regardless of risk topic) reported experiencing higher levels of fear. Higher levels of fear were associated with more positive thoughts about the message (in alignment with the message advocacy) and fewer negative thoughts about the message (against the message advocacy), both of which influenced message attitudes. Finally, message attitudes were associated with increased information seeking and intentions to engage in risk reduction behaviors.

Construction and Evaluation of an Instrument to Measure High School Students Biological Content Knowledge

Kathy L. Malone, William J. Boone, Andria Stammen, Anita Schuchardt, Lin Ding, Zakee Sabree. EURASIA Journal of Mathematics, Science and Technology Education, 2021, 17(12), em2048. https://doi.org/10.29333/ejmste/11376

Abstract

Instruments for assessing secondary students’ conceptual understanding of core concepts in
biology are needed by educational practitioners and researchers alike. Most instruments available
for secondary biology (years 9 to 12) focus only on highly specific biological concepts instead of
multiple core concepts. This study describes the development of a 25-item instrument designed
to fill this gap, the High School Biology Concept Inventory (HS-BCI). The HS-BCI not only assesses
student knowledge of key biological concepts but also alternative conceptions. Using Rasch
theory, the initial instrument was constructed from a pool of 61 instrument items using test results
from 1015 students. The final 25-item instrument was validated with 1955 students. The results
provide reliability and validity evidence for the HS-BCI. The findings suggest that it can be utilized
to assess both conceptual knowledge and alternative conceptions.

Assessing the efficacy of higher-taxon approach for ant species surveys to improve biodiversity inventories

Jorge Luiz Pereira Souza, Itanna Oliveira Fernandes, Donat Agosti, Norman F. Johnson, Fabrício Beggiato Baccaro. 2021. Animal Conservation. https://doi.org/10.1111/acv.12758

Abstract

Understanding the distribution of species is essential for the conservation and management of biodiversity. But the availability of this kind of information is still scarce for the most diverse regions. The higher-taxon approach (i.e. use of coarser taxonomic levels to represent species) as an easier and efficient method in representing species patterns can be one way to overcome these constraints. However, there is a general lack of information about the taxonomic stability of surrogate taxa across space and time. We investigated the predictive power and stability of taxonomic identification at the genus level as a predictor of ant species (Hymenoptera: Formicidae) distribution throughout ˜1000 km along the Amazon Basin, using taxonomy over the past 120 years. Using intervals of 10 years, from 1900 to 2020 we generated a genus and species matrix based on actual data from our sampling sites for each decade over a total of 120 years. We tested the predictive power of genera as a surrogate of species for approximating species-level richness, composition and distribution-based measures along topographic gradients at local (within site) and regional (between sites) scales. We detected a strong correlation between genera and ant species richness in the current database. There was also high congruence between genera and ant species composition over the time period studied. Genera were also efficient at detecting patterns of species distribution along topographic gradients. Despite changes in ant taxonomy over the past 120 years, our data indicate that such revisions did not affect the ability of ant genera to predict general patterns of ant species in our study area within the Amazon Basin. This reinforces the potential of genera to serve as surrogates for ant species elsewhere, which may significantly decrease the cost of surveying ants in environmental monitoring programs because of the time saved from identifying collected specimens to genus rather than species level.