EEOB Publications November 1 - November 30
Fish Diet Shifts Associated with the Northern Gulf of Mexico Hypoxic Zone
Cassandra N. Glaspie, Melissa Clouse, Klaus Huebert, Stuart A. Ludsin, Doran M. Mason, James J. Pierson, Michael R. Roman, Stephen B. Brandt. 2019. Estuaries and Coasts. https://doi.org/10.1007/s12237-019-00626-x
The occurrence of low dissolved oxygen (hypoxia) in coastal waters may alter trophic interactions within the water column. This study identified a threshold at which hypoxia in the northern Gulf of Mexico (NGOMEX) alters composition of fish catch and diet composition (stomach contents) of fishes using fish trawl data from summers 2006–2008. Hypoxia in the NGOMEX impacted fish catch per unit effort (CPUE) and diet below dissolved oxygen thresholds of 1.15 mg L−1 (for fish CPUE) and 1.71 mg L−1 (for diet). CPUE of many fish species was lower at hypoxic sites (≤ 1.15 mg L−1) as compared to normoxic regions (> 1.15 mg L−1 ), including the key recreational or commercial fish species Atlantic croaker Micropogonias undulatus and red snapper Lutjanus campechanus. Overall, fish diets from hypoxic sites (≤ 1.71 mg L−1 ) and normoxic sites (> 1.71 mg L−1 ) differed. Fish caught in normoxic regions consumed a greater mass of benthic prey (ex. gastropods, polychaetes) than fish caught in hypoxic regions. Hypoxia may increase predation risk of small zooplankton, with observations of increased mass of small zooplankton in fish stomachs when bottom hypoxia was present. Changes in contributions of small zooplankton and benthic prey to fish diet in hypoxic areas may alter energy flow in the NGOMEX pelagic food web and should be considered in fishery management.
Arthropod fauna associated with black vulture and turkey vulture nests (Accipitriformes: Cathartidae) in south-Central Kentucky, USA
William L. Lynch, T. Keith Philips, Hans Klompen. 2019. H. Biologia. https://doi.org/10.2478/s11756-019-00359-z
Arthropods were collected from seven black vulture and two turkey vulture nests in South-Central Kentucky. Species diversity in each nest ranged from a low of two to 10 species in total. Three nest cavities that had the highest amount of heterogeneous organic matter concomitantly had the highest number of arthropod taxa. Insects were the most abundant arthropods and included taxa from the orders Coleoptera, Diptera, Hemiptera, Hymenoptera, Lepidoptera and Psocoptera. Diptera and Coleoptera were represented by the highest number of families (and species), with seven (ten spp.) and four (eight spp.), respectively. Discovered Acari included eight species in seven families, of which four were members of the Mesostigmata. A majority of the insects collected were either scavengers or accidentals and do not have a strong link with the nest habitat. But taxa associated with guano or feathers for food sources or those that are predacious on fly eggs or larvae appear to have a loose association with these vulture nests.
Onset of seasonal metabolic depression in the Antarctic midge Belgica antarctica appears to be independent of environmental cues
Drew E. Spacht, J. D. Gantz, Richard E. Lee Jr., David L. Denlinger. 2019. Physiological Entomology. https://doi.org/10.1111/phen.12311
Seasonal progression is tracked in most animals by changes in daylength, thus allowing reliable synchrony with abundant food and favourable developmental conditions. In polar regions, daylength varies extensively, fluctuating at the highest latitudes from persistent light to persistent dark. The Antarctic midge Belgica antarctica has a narrow seasonal window in which to feed and develop, and previous work shows that this insect, despite having the elements of a circadian clock, remains continuously active when temperatures are permissive. The present study aims to clarify seasonal tracking in B. antarctica during the austral summer by monitoring oxygen consumption rates in a field population and in experimental groups exposed to shortened daylength, dehydration and chilling. Remarkably, during March, coordinated decreases in oxygen consumption are observed, ranging from 18% to 42%, in all treatment groups, indicating an anticipatory response to seasonal change regardless of the environmental cues. These results suggest that B. antarctica relies on an intrinsic mechanism to program metabolic depression at the onset of the long austral winter.
Process‐based species delimitation leads to identification of more biologically relevant species
Megan L. Smith and Bryan C. Carstens. 2019. Evolution. https://doi.org/10.1111/evo.13878
Most approaches to species delimitation to‐date have considered divergence‐only models. While these models are appropriate for allopatric speciation, their failure to incorporate many of the population‐level processes that drive speciation, such as gene flow (e.g. in sympatric speciation), places an unnecessary limit on our collective understanding of the processes that produce biodiversity. To consider these processes while inferring species boundaries, we introduce the R‐package delimitR and apply it to identify species boundaries in the reticulate taildropper slug (Prophysaon andersoni). Results suggest that secondary contact is an important mechanism driving speciation in this system. By considering process, we both avoid erroneous inferences that can be made when population‐level processes such as secondary contact drive speciation but only divergence is considered, and gain insight into the process of speciation in terrestrial slugs. Further, we apply delimitR to three published empirical datasets and find results corroborating previous findings. Finally, we evaluate the performance of delimitR using simulation studies, and find that error rates are near zero when comparing models that include lineage divergence and gene flow for three populations with a modest number of Single Nucleotide Polymorphisms (SNPs; 1,500) and moderate divergence times (< 100000 generations). When we apply delimitR to a complex model set (i.e. including divergence, gene flow, and population size changes), error rates are moderate (∼0.15; 10000 SNPs), and, when present, misclassifications occur between highly similar models.
The emerging field of venom-microbiomics for exploring venom as a microenvironment, and the corresponding Initiative for Venom Associated Microbes and Parasites (iVAMP)
Sabah Ul-Hasan, Eduardo Rodríguez-Román, Adam M. Reitzel, Rachelle M.M. Adams, Volker Herzig, Clarissa J. Nobile, Anthony J. Saviola, Steven A. Trim, Erin E. Stiers, Sterghios A. Moschos, Carl N. Keiser, Daniel Petras, Yehu Moran, Timothy J. Colston. 2019.Toxicon: X. DOI: 10.1016/j.toxcx.2019.100016.
Venom is a known source of novel antimicrobial natural products. The substantial, increasing number of these discoveries have unintentionally culminated in the misconception that venom and venom-producing glands are largely sterile environments. Culture-dependent and -independent studies on the microbial communities in venom microenvironments reveal the presence of archaea, algae, bacteria, fungi, protozoa, and viruses. Venom-centric microbiome studies are relatively sparse to date with the adaptive advantages that venom-associated microbes might offer to their hosts, or that hosts might provide to venom-associated microbes, remaining largely unknown. We highlight the potential for the discovery of venom microbiomes within the adaptive landscape of venom systems. The considerable number of convergently evolved venomous animals, juxtaposed with the comparatively few known studies to identify microbial communities in venom, provides new possibilities for both biodiversity and therapeutic discoveries. We present an evidence-based argument for integrating microbiology as part of venomics (i.e., venom-microbiomics) and introduce iVAMP, the Initiative for Venom Associated Microbes and Parasites (https://ivamp-consortium.github.io/), as a growing collaborative consortium. We express commitment to the diversity, inclusion and scientific collaboration among researchers interested in this emerging subdiscipline through expansion of the iVAMP consortium.
Interactive effects of hypoxia and temperature on consumption, growth, and condition of juvenile Hybrid Striped Bass
Benjamin J. Marcek, Emily A. Burbacher, Konrad Dabrowski, Kim P. Winslow, Stuart A. Ludsin. 2019. Transactions of the American Fisheries Society. https://doi.org/10.1002/tafs.10210
Productive tributary reservoirs can become suboptimal environments for fish during summer because of hypolimnetic hypoxia (≤ 3 mg O2/L) and high epilimnetic temperatures that reduce access to quality habitat for growth. We conducted a laboratory experiment, using a 3 × 3 × 2 (temperature × dissolved oxygen × fish size) complete factorial design to examine the effect of dissolved oxygen concentration (DO) and temperature on consumption, growth, and proximal body composition of juvenile Hybrid Striped Bass (Morone saxatilis × M. chrysops), which are commonly stocked into North American reservoirs and for which tolerances to environmental conditions are not fully known. Our study demonstrates that consumption and growth of juvenile Hybrid Striped Bass were affected by an interaction between temperature and DO. Specifically, low DO conditions negatively affected consumption, especially at high temperatures. By contrast, growth was largely unaffected by DO, except at high temperatures when low DO reduced fish growth. Temperature and DO did not interact to cause changes in energy density or moisture content, although temperature did independently affect the moisture content of Hybrid Striped Bass tissues. The change in moisture content was lowest for fish exposed to high temperatures, suggesting a negative effect of temperature on fish condition. Collectively, our experimental findings provide useful information for modeling the energetics of Hybrid Striped Bass and assessing reservoir habitat quality, which can help guide decision‐making regarding stocking.
Multi-decadal shifts in forest plant diversity and community composition across glacial landforms in northern lower Michigan, USA.
Raleigh Dean Ricart, Douglas R. Pearsall, Peter S. Curtis. 2019. Canadian Journal of Forest Research, https://doi.org/10.1139/cjfr-2019-0138
Understanding how plant community assemblage is affected by spatial and temporal patterns is crucial to understanding forest ecosystem responses to disturbance, including future climate change. Here we tracked how diversity and composition are distributed through space and time in a mid-successional mixed hardwood forest in northern lower Michigan, USA. This region’s geographically and abiotically distinct glacial landforms influence both the spatial and temporal dynamics of its forest communities. Vegetation sampling plots (n=87) were established at the University of Michigan Biological Station in 1990 and resampled in 2015. Vegetation in the overstory, sapling, and groundcover layers was censused. Abiotic variables, including elevation, pH, and soil nutrients, were measured in a subset of plots (n=40). There were strong differences in diversity and community composition among glacial landforms, with the Moraine (MOR) having a 31% greater species richness in the groundcover layer than the other glacial landforms. Surprisingly, plant communities across all three vegetation layers showed little change over the twenty-five-year period and we found no evidence of differences in successional rates between landforms. Our findings indicate a large influence of glacial landforms on the production and maintenance of local plant diversity and community composition in this area and also suggest that successional dynamics may manifest themselves over much longer time periods in these northern biomes.
Revision of the Afrotropical genus Pulchrisolia Szabó (Hymenoptera, Platygastridae, Sceliotrachelinae)
Zachary Lahey, Simon van Noort, Andrew Polaszek, Lubomir Masner, Norman Johnson. 2019. In: Talamas E (Eds) Advances in the Systematics of Platygastroidea II. Journal of Hymenoptera Research 73: 39-71. https://doi.org/10.3897/jhr.73.33876
The genus Pulchrisolia Szabó is revised. Pulchrisolia maculata Szabó is redescribed and nine species are described as new: P. ankremos Lahey, sp. nov. (Ghana, Ivory Coast), P. asantesana van Noort & Lahey, sp. nov. (South Africa), P. diehoekensis van Noort & Lahey, sp. nov. (South Africa), P. ellieae Lahey, sp. nov. (Madagascar), P. nephelae Lahey, sp. nov. (Benin, Burkina Faso, Gambia, Ivory Coast, Mali, Nigeria), P. robynae van Noort & Lahey, sp. nov. (South Africa), P. sanbornei Lahey & Masner, sp. nov. (South Africa), P. teras Lahey, sp. nov. (Madagascar), and P. valerieae Polaszek & Lahey, sp. nov. (Zambia). The genus is diagnosed from Afrisolia Masner & Huggert, Isolia Förster, and Sceliotrachelus Brues, and a key is provided to the platygastrid genera of the Isolia-cluster.
Revision of Aleyroctonus Masner & Huggert (Hymenoptera, Platygastridae, Sceliotrachelinae)
Zachary Lahey, Lubomír Masner, Norman F. Johnson, Andrew Polaszek. 2019. In: Talamas E (Eds) Advances in the Systematics of Platygastroidea II. Journal of Hymenoptera Research 73: 73-93. https://doi.org/10.3897/jhr.73.38383
The genus Aleyroctonus Masner & Huggert is revised. Aleyroctonus pilatus Masner & Huggert is redescribed, and two species are described as new: A. miasmus Lahey & Polaszek, sp. nov. (Australia) and A. stanslyi Lahey & Polaszek, sp. nov. (Australia). We consider Aleyroctonus to be most closely related to a complex of three morphologically similar genera: Aphanomerus Perkins, Austromerus Masner & Huggert, and Helava Masner & Huggert. Aleyroctonus is diagnosed from other genera of Sceliotrachelinae and a key is provided to the platygastrid genera of the Aphanomerus-cluster.
Proterosceliopsidae: A new family of Platygastroidea from Cretaceous amber
Elijah J. Talamas, Norman F. Johnson, Chungkun Shih, Dong Ren. 2019. In: Talamas E (Eds) Advances in the Systematics of Platygastroidea II. Journal of Hymenoptera Research 73: 3-38. https://doi.org/10.3897/jhr.73.32256
Proterosceliopsis was erected by Ortega-Blanco et al. (2014) in their treatment of scelionid genera in Cretaceous amber from Álava, Spain. The generic description appears to have been based on specimens in which only the dorsal aspects of the mesosoma and metasoma were visible, as characters of the mesopleuron, metapleuron, lateral pronotum, and ventral metasoma were not mentioned. We here provide a comprehensive description of the genus that includes characters from throughout the body and we reinterpret some of the characters presented by Ortega-Blanco et al. (2014). Our analysis of Proterosceliopsis in the context of extant and fossil platygastroids places this group as a lineage well outside of the current families. We here designate Proterosceliopsis as the type genus of a new family, Proterosceliopsidae Talamas, Johnson, Shih & Ren, fam. nov., and describe five new species: Proterosceliopsis ambulata Talamas, Shih & Ren, sp. nov., P. nigon Talamas, Shih & Ren, sp. nov., P. plurima Talamas, Shih & Ren, sp. nov., P. torquata Talamas, Shih & Ren, sp. nov., and P. wingerathi Talamas, Shih & Ren, sp. nov. We provide a key to all presently known species in the genus. The oldest known specimen of Platygastridae s.s., in Burmese amber, is presented and compared to Proterosceliopsidae fam. nov.
Testicular collections as a technique to increase milt availability in sauger (sander canadensis)
Bryan Blawuta, Barbara Wolfe, Christa R. Moraes, Douglas Sweet, Stuart A. Ludsin, Marco A. Coutinho da Silva. 2019. https://doi.org/10.1016/j.anireprosci.2019.106240
This study was conducted to compare quality and quantity of sperm collected from sauger (S. canadensis) using two collection methods: stripping alone and testicular tissue collection combined with stripping. Sperm were collected from sauger broodstock (n = 20) during the breeding season. Fish were randomly assigned to two sperm collection groups: (1) stripping once or (2) stripping twice before testicular tissue collection for obtaining additional sperm. Sperm motility variables, morphology, total number produced, and fertilization (%) were compared using the two collection methods. Testicular sperm had greater total motility (70.1 ± 2.1% compared with 44.3 ± 5.7%) but there were fewer morphologically normal cells (76.4 ± 1.3% compared with 92.8 ± 1.0%) compared to sperm collected using the stripping procedure. Sperm collection regimen utilizing testicular collections and sperm extractions in combination with stripping resulted in a ∼ten fold increase in total number of motile and morphologically normal sperm (39.5 ± 4.1 × 10 9) compared with the currently utilized two sequential sperm stripping collection procedures alone (3.6 ± 4.1 × 10 9 sperm). In large-scale studies (150,000 eggs), fertilization, using sperm collected from testicular tissues (1.0 × 105 motile sperm/egg), was similar to sperm collected with only the stripping procedure (71.2 ± 5.5 %, 81.2 ± 5.5 %, P = 0.265). The results of this study indicate testicular collection combined with sperm extractions allows for collection of sperm of a quantity and quality to maximize fry production and reduce the problems with lack of broodstock availability for sperm collection.
New Species of the Genus Periglischrus (Acari: Spinturnicidae) from Monophyllus Bats (Chiroptera: Phyllostomidae) in the West Indies, Including a Morphometric Analysis of Its Intraspecific Variation
Juan B Morales-Malacara, Gabriela Castaño-Meneses, Hans Klompen, Carlos A Mancina. 2019. Journal of Medical Entomology, tjz198, https://doi.org/10.1093/jme/tjz198
The discovery of a new species, Periglischrus empheresotrichus, was determined through a review of museum collections, as well as a field survey of ectoparasites of island bats. This new species parasitizes on two bat species of the genus Monophyllus Leach, the Greater Antillean Long-tongued bat Monophyllus redmani Leach and the Lesser Antillean Long-tongued bat Monophyllus plethodon Miller. The female, male, deuthonymphs, and protonymph are described and illustrated. P. empheresotrichus n. sp. has an insular distribution, we evaluated the morphological variation of the adult populations, and concluded that intra-specific variation is correlated both with host species and locality (island) in the West Indies.
RAD‐seq refines previous estimates of genetic structure in Lake Erie walleye (Sander vitreus)
Kuan‐Yu Chen, Peter T. Euclide, Stuart A. Ludsin, Wes Larson, Michael G. Sovic, H. Lisle Gibbs, Elizabeth A. Marschall. 2019. https://doi.org/10.1002/tafs.10215
Delineating population structure helps fishery managers maintain a diverse “portfolio” of local spawning populations (stocks), as well as facilitate stock‐specific management. In Lake Erie, commercial and recreational fisheries for walleye (Sander vitreus) exploit numerous local spawning populations, which cannot be easily differentiated using traditional genetic data (e.g., microsatellites). Here, we used genomic information (12,264 polymorphic loci) generated using RAD‐seq to investigate stock structure in Lake Erie walleye. We found low genetic divergence (FST = 0.0006–0.0019) among the four western basin stocks examined, which resulted in low classification accuracies for individual samples (40–60%). However, more structure existed between west and eastern basin stocks (FST = 0.0042–0.0064), resulting in> 95% classification accuracy of samples to a lake basin. Thus, our success in using genomics to identify stock structure varied with spatial scale. Based on our results, we offer recommendations to improve the efficacy of this new genetic tool for refining stock structure and eventually determining relative stock contributions in Lake Erie walleye and other Great Lakes populations.