Regional ß-Diversity of Stream Insects in Coastal Alabama Is Correlated with Stream Conditions, Not Distance among Sites.

ß-diversity is often measured over both spatial and temporal gradients of elevation, latitude, and environmental conditions. It is of particular interest to ecologists, as it provides opportunities to test and infer potential causal mechanisms determining local species assemblages. However, studies of invertebrate ß-diversity, especially aquatic insects, have lagged far behind other biota. Using partial Mantel tests, we explored the associations between ß-diversity of insects found in the coastal streams of Alabama, USA, and stream conditions and distances among sites. ß-diversity was expressed using the Sørensen index, ßSor, stream conditions were expressed as principal components (PCs), and distances as Euclidean distances (km) among sites. We also investigated the impact of seasonality (fall, summer) and taxonomic resolution (genus, species) on ßSor. Regardless of season, ßSor was significantly correlated (p < 0.01; r > 0.44) with stream conditions (stream size and water chemistry), while taxonomic resolution had minimal effect on associations between ßSor and stream conditions. Distance was never correlated with changes in ßSor (p > 0.05). We extended the use of the Sørensen pair-wise index to a multiple-site dissimilarity, ßMult, which was partitioned into patterns of spatial turnover (ßTurn) and nestedness (ßNest). Changes in ßMult were driven mostly by turnover rather than nestedness.

A critical appraisal of ankle rehabilitative interventions.

Introduction Lateral ankle sprain is a common musculoskeletal pathology. Functional exercise progression is vital to restore full function. Aim The aim of this study was to compare the electromyographical response to a standard balance task on one stable and four unstable surfaces. Participants Twenty subjects (5 male, 15 females; age at 23 ± 7.1 years) were recruited to participate in the study. Methods A gym-based single session cross over design was used to compare peak and mean surface EMG (sEMG) activity of the Peroneus Longus, Tibilais Anterior and medial head of the gastrocnemius muscles whilst performing a standardized balance task on one stable surface and four unstable surfaces stable surface. Results A significant main effect for surface was found. Post-hoc testing revealed that the Floor and Trampoline (Trampet) elicited similar mean sEMG response. Discussion The results of the study propose a safe and stepwise progressive rehabilitation regime following ankle injury whilst considering the healing process of the injured structure.

Tick-Borne Pathogens Associated with Medically Important Ticks in Alabama: A Four-Year Survey.

Background: Tick-borne diseases (TBDs) represent a significant threat to human health in the United States. Based on reported cases of notifiable TBDs to the Centers for Disease Control and Prevention (CDC) the state of Alabama is no exception, yet previously there has been no active surveillance program in place to comprehensively assess the presence and prevalence of tick vectors and their associated TBD pathogens in Alabama. Here we summarize initial findings from a 4-year survey to address this unmet need. Materials and Methods: Beginning in 2018 and proceeding through 2021, ticks were collected throughout the state of Alabama and pooled before being screened for a panel of TBD pathogens known to circulate in the United States. Results: Consistent with previously reported cases, TBD pathogens associated with anaplasmosis, babesiosis, ehrlichiosis, and spotted fever rickettsiosis were detected in ticks of Alabama. Causative agents for tularemia and Lyme disease were not detected despite previously reported human disease cases. There was also no evidence of Heartland virus despite recent reports of the virus being detected in ticks in Northwestern counties. Conclusions: While these results serve to provide some insights into TBD pathogens associated with ticks in Alabama, they also raise many questions that highlight the need for additional studies and continued surveillance to fully understand the TBD threat to human health in Alabama.

Statewide survey of medically important ticks on white-tailed deer, Odocoileus virginianus Zimmerman, in Alabama, U.S.A.

A statewide survey of the tick fauna found on deer, using harvested deer heads as the sample unit, was conducted during the Alabama hunting seasons of 2019-2020 and 2020-2021. Four species of ticks: Ixodes scapularis (n= 936, % of catch 69.1%), Amblyomma americanum (315, 23.2%), Dermacentor albipictus (97, 7.1%), and Amblyomma maculatum (6, 0.4%) were taken from 151 deer heads harvested from 21 deer processing centers (n = 4-17 heads/processor). A total of 87.7% (prevalence) of deer heads had one or more ticks. We used two standard numerical descriptors of tick numbers, abundance, and relative abundance. No significant stepwise regressions (p > 0.05) were found between tick abundance (all ticks, I. scapularis, A. americanum) and the predictor variables of latitude, deer density, season, and year. In addition, the correlation between the abundance of I. scapularis and A. americanum was not significant (p > 0.5). In contrast, the relative abundance of both I. scapularis and A. americanum showed a significant (P < 0.05) relationship with latitude, with the relative abundance of I. scapularis increasing on deer with increased latitude and A. americanum showing the opposite pattern.

Ticks of Alabama: the fauna and spatial distribution of medically important species across the state.

The last statewide survey of hard ticks in Alabama was in 1972. To address this deficit, we examined the distribution of the medically important species across the state, Ixodes scapularis (Say), Dermacentor variabilis (Say), Amblyomma americanum (L.), and A. maculatum (Koch), between April, 2018 and February, 2021. Collections primarily involved dragging (April to July) and examination of harvested deer (November to February). A total of 2,927 ticks was collected from 110 sites; three species, I. scapularis, A. americanum, and D. variabilis, represented 91.70% of all ticks collected. Amblyomma americanum and D. variabilis were the most common species encountered in drags; I. scapularis dominated deer collections. Dermacentor variabilis was never found on deer, whereas D. albipictus was only found on deer. Stepwise regression (AIC) of drag data was linked to several site variables. Results suggest a linear response along a south (low abundance) to north (high abundance) gradient, in addition to increased abundance at sites with lower temperatures and greater precipitation and canopy cover.

The general architecture of black fly-parasite interactions: Parasitism in lotic systems at a continental scale.

We examined the general architecture of interactions between stream-dwelling larval black flies (Diptera: Simuliidae) and their common parasites in 1736 collections across North America. Mermithid nematodes (family Mermithidae), microsporidia (phylum Microsporidia), and the fungus Coelomycidium simulii Debaisieux (phylum Blastocladiomycota) infected larval black flies. We found similar continental distributions for these three parasite taxa across North America. At least one of these taxa was represented in 42.2% of all black fly collections. Species interactions in ecological networks typically imply that each link between species is equally important. By employing quantitative measures of host susceptibilities and parasite dependencies, we provide a more complete structure for host-parasite networks. The distribution of parasite dependencies and host susceptibilities were right-skewed, with low values indicating that most dependencies (parasites) and susceptibilities (hosts) were weak. Although regression analysis between host frequency and parasite incidence were highly significant, frequency analysis suggested that the distributions of parasites differ significantly among the four most common and closely related (same subgenus) species of hosts. A highly significant pattern of nestedness in our bipartite host-parasite network indicated that specialized parasites (i.e., those that interact with few host species) tend to occur as subsets of the most common hosts.

Quantifying Functional Ankle Rehabilitation Progression Criteria Using GPS: A Preliminary Study.

CONTEXT: Contemporary developments in Global Positioning System (GPS) technology present a means of quantifying mechanical loading in a clinical environment with high ecological validity. However, applications to date have typically focused on performance rather than rehabilitation. OBJECTIVE: To examine the efficacy of GPS microtechnology in quantifying the progression of loading during functional rehabilitation from ankle sprain injury, given the prevalence of reinjury and need for quantifiable monitoring. Furthermore, to examine the influence of unit placement on the clinical interpretation of loading during specific functional rehabilitation drills. DESIGN: Repeated measures. SETTING: University athletic facilities. PARTICIPANTS: Twenty-two female intermittent team sports players. INTERVENTION: All players completed a battery of 5 drills (anterior hop, inversion hop, eversion hop, diagonal hop, and diagonal hurdle hop) designed to reflect the mechanism of ankle sprain injury, and progress functional challenge and loading. MAIN OUTCOME MEASURES: GPS-mounted accelerometers quantified uniaxial PlayerLoad for each drill, with units placed at C7 and the tibia. Main effects for drill type and GPS location were investigated. RESULTS: There was a significant main effect for drill type (P < .001) in the mediolateral (η2 = .436), anteroposterior (η2 = .480), and vertical planes (η2 = .516). The diagonal hurdle hop elicited significantly greater load than all other drills, highlighting a nonlinear progression of load. Only the mediolateral load showed evidence of progressive increase in loading. PlayerLoad was significantly greater at the tibia than at C7 for all drills, and in all planes (P < .001, η2 ≥ .662). Furthermore, the tibia placement was more sensitive to between-drill changes in mediolateral load than the C7 placement. CONCLUSIONS: The placement of the GPS unit is imperative to clinical interpretation, with both magnitude and sensitivity influenced by the unit location. GPS does provide efficacy in quantifying multiplanar loading during (p)rehabilitation, in a field or clinical setting, with potential in extending GPS analyses (beyond performance metrics) to functional injury rehabilitation and prevention.

The influence of habitat heterogeneity and latitude on gamma diversity of the Nearctic Simuliidae, a ubiquitous group of stream-dwelling insects.

Among the most prominent, large-scale patterns of species richness are the increases in richness with decreasing latitude and with increasing habitat heterogeneity. Using the stream-dwelling larval and pupal stages of North American black flies (Diptera: Simuliidae), we address 3 broad questions about species richness: (i) Does a significant latitude-richness relationship exist? (ii) How does habitat heterogeneity influence gamma diversity? (iii) What is the sign (positive or negative) of the latitude-richness and the heterogeneity-richness relationships? We found no evidence that habitat heterogeneity influences gamma diversity. The estimated peak species richness for black flies in North America was at 50-53°N, which also corresponds with peak generic richness. All plesiomorphic, extant lineages of the Simuliidae in the Western Hemisphere are found in cool mountainous environments of North America, suggesting that peak richness at 50-53°N might be a signature of this phylogenetic pattern and a reflection of underlying historical processes.

Biodiversity of Simulium metallicum sensu lato (Diptera: Simuliidae), a complex of Neotropical vectors associated with human onchocerciasis.

The polytene chromosomes of 130 larvae of the Neotropical Simulium metallicum complex from Brazil, Costa Rica, and Ecuador revealed five cytoforms, including three ('M', 'N', and 'O') that are new and two ('B' and 'J') that represent range extensions of up to 850km. The discovery of three new cytoforms brings the total number in the complex to 17. Cytoforms 'B', 'J', and 'N' are reproductively isolated from one another, and their species status is corroborated by morphological evidence. None of the three new cytoforms is known from current or historical onchocerciasis foci, although 'M' inhabits the periphery of the former Ecuadorian Santiago onchocerciasis focus a mere 30km to the west. The number of fixed chromosomal differences, as many as 24, separating some members of the S. metallicum complex far exceeds that known between members of any other simuliid species complex. Two distinct groupings can be diagnosed within the S. metallicum complex, based on at least eight fixed chromosomal rearrangements and structural characters in the larval stage. Consequently, a recommendation is made to recognize the S. horacioi complex and the S. metallicum complex sensu stricto. Recognition of two separate complexes provides potential phylogenetic content with predictive power for understanding biological phenomena such as vector potential.

Towards optical polarization control of laser-driven proton acceleration in foils undergoing relativistic transparency.

Control of the collective response of plasma particles to intense laser light is intrinsic to relativistic optics, the development of compact laser-driven particle and radiation sources, as well as investigations of some laboratory astrophysics phenomena. We recently demonstrated that a relativistic plasma aperture produced in an ultra-thin foil at the focus of intense laser radiation can induce diffraction, enabling polarization-based control of the collective motion of plasma electrons. Here we show that under these conditions the electron dynamics are mapped into the beam of protons accelerated via strong charge-separation-induced electrostatic fields. It is demonstrated experimentally and numerically via 3D particle-in-cell simulations that the degree of ellipticity of the laser polarization strongly influences the spatial-intensity distribution of the beam of multi-MeV protons. The influence on both sheath-accelerated and radiation pressure-accelerated protons is investigated. This approach opens up a potential new route to control laser-driven ion sources.

The roles of abiotic factors, dispersal, and species interactions in structuring stream assemblages of black flies (Diptera: Simuliidae).

BACKGROUND: The patterns and drivers of species assemblages represent the core of community ecology. We focus on the assemblages of a single family of ubiquitous lotic insects, the Simuliidae (black flies), of which the larvae play a critical role in resource turnover in steams. We use Mantel tests and null models to tease out the potential influence of abiotic stream conditions, species interactions, and dispersal on the assemblage patterns of larval black flies over two spatial scales (within and across ecoregions) and two seasons (spring and summer). RESULTS: When stream sites were considered across ecoregions in the spring, stream conditions and dispersal were correlated significantly with species similarity; however, within ecoregions in the spring, dispersal was important only in the Piedmont and Sandhills and abiotic factors only in the Mountains. In contrast, results of the summer analyses within and across ecoregions were congruent; assemblage similarity was significantly correlated with stream conditions both across and within ecoregions. Null models suggested that patterns of species segregation in the spring were consistent with a community structured by competition, whereas patterns in the summer were consistent with species assemblages influenced by abiotic factors. CONCLUSIONS: Species composition of black flies at streams sites is correlated with dispersal factors and stream conditions, but results vary over spatial and temporal scales. Communities of black flies can be viewed within a metacommunity context; local assemblages are consistent with species sorting and mass effects. Given that black flies have a terrestrial stage, with females deciding where to place the eggs, a full understanding of the processes that determine local aquatic assemblages will require integration of the dynamics of the aquatic immature stages and the terrestrial adults.

Morphological differences of symbiotic fungi Smittium culisetae (Harpellales: Legeriomycetaceae) in different Dipteran hosts.

Harpellales (Legeriomycetaceae, Zygomycota) or 'trichomycetes' are fungi that inhabit the digestive tracts of arthropods such as insects, millipedes, and crustaceans. In the current study we examined changes in 5 morphological characters of Smittium culisetae (Harpellales: Legeriomycetaceae) between the two dipteran (mosquito, black fly) hosts reared under 3 different temperatures (17, 22, 30 degrees C). Both host and temperature had a pervasive effect on the linear dimension of trichospores, their generative cells and hyphae width. At 30 degrees C the mean size of all 5 morphological characters were consistently larger in fungus taken from the mosquito host than from the black fly host. At 17 degrees C and 22 degrees C, however, there were no consistent patterns. The effect of host was so pronounced that it could be accurately determined which host S. culisetae colonised based on differences in linear morphology. Such changes in fungal morphology between hosts have important ramifications for the morphologically based taxonomy of this group.

Predicting occurrence of the fungal symbiote Harpella colonizing black fly larvae in coastal streams of Alabama and Mississippi, USA.

The environmental conditions governing symbioses are poorly known in aquatic systems. Stream conditions associated with the distribution of the black fly (Simuliidae) midgut symbiote Harpella were investigated in southern Alabama and Mississippi streams. Stream conditions that were most useful in predicting the distribution of Harpella spp. in the study area were dissolved oxygen and water temperature. Presence of Harpella species in streams was associated with higher dissolved oxygen and decreased water temperature compared to streams where Harpella spp. was absent. Stream conditions associated with the distribution of Harpella spp. in other regions of the world vary according to conditions other than those elucidated here, indicating that geography, host species, and stream conditions play important roles in the spatial distribution of Harpella species.

Do different species of Smittium (Harpellales, Legeriomycetaceae) influence each other in the host gut?

Smittium (Harpellales, Legeriomycetaceae) belongs to a cosmopolitan group of filamentous fungi (Trichomycetes, Zygomycota) that live as obligate commensals in the digestive tract of various marine, freshwater, and terrestrial arthropods. The outcome of the paired introductions of three species of Smittium was investigated within the individual hosts of the mosquito Aedes aegypti (Culicidae: Diptera). In the first set of experiments, the host was inoculated with a single species of Smittium to determine whether hyphae location within the host was species specific. In the second experiment the host was exposed to two species of Smittium to determine whether hyphae showed positional displacement when two species of fungi co-inhabited the same host gut. Single species introductions of Smittium resulted in 80-85% of hosts with hyphae present only in the rectum. In all three paired combinations of Smittium species examined, only 40-65% of host larvae had hyphae restricted to the rectum. This is first study to experimentally demonstrate that the microdistribution of Harpellaceae hyphae can be influenced by the presence of a second species of Harpellaceae, suggesting a competition of the symbionts within the host.

The effect of temperature and host species on the development of the trichomycete Smittium culisetae (Zygomycota).

We examined the growth and development of the trichomycete Smittium culisetae (Harpellales: Legeriomycetaceae) in the larval hosts Simulium vittatum Zetterstedt (Diptera: Simuliidae) and Aedes aegypti (L.) (Diptera: Culicidae) at three temperatures, 17, 22 and 30 C. Trichospore maturation of Sm. culicetae external to the host as well as the ability of these trichospores to colonize new hosts also was investigated. Although the development of Sm. culisetae varied with both temperature and host there was a pattern of maximum trichospore production at 48-72 h postinoculation. In addition thalli under laboratory conditions are capable of spore production after extraction from a host and these trichospores can colonize new hosts. Furthermore this was noted to occur in both host species. These results suggest that synchrony between host and symbiont development is not as tightly coupled as previously assumed.

In situ studies of algal biomass in relation to physicochemical characteristics of the Salt Plains National Wildlife Refuge, Oklahoma, USA.

This is the first in a series of experiments designed to characterize the Salt Plains National Wildlife Refuge (SPNWR) ecosystem in northwestern Oklahoma and to catalogue its microbial inhabitants. The SPNWR is the remnant of an ancient ocean, encompassing approximately 65 km2 of variably hypersaline flat land, fed by tributaries of the Arkansas River. Relative algal biomass (i.e., chlorophyll concentrations attributed to Chlorophyll-a-containing oxygenic phototrophs) and physical and chemical parameters were monitored at three permanent stations for a one-year period (July 2000 to July 2001) using a nested block design. Salient features of the flats include annual air temperatures that ranged from -10 to 40 degrees C, and similar to other arid/semi-arid environments, 15-20-degree daily swings were common. Shade is absent from the flats system; intense irradiance and high temperatures (air and sediment surface) resulted in low water availability across the SPNWR, with levels of only ca. 15 % at the sediment surface. Moreover, moderate daily winds were constant (ca. 8-12 km h-1), sometimes achieving maximum speeds of up to 137 km h-1. Typical of freshwater systems, orthophosphate (PO(4)3-) concentrations were low, ranging from 0.04 to <1 microM; dissolved inorganic nitrogen levels were high, but spatially variable, ranging from ca. 250-600 microM (NO(3)- + NO(2)-) and 4-166 microM (NH(4)+). Phototroph abundance was likely tied to nutrient availability, with high-nutrient sites exhibiting high Chl-a levels (ca. 1.46 mg m-2). Despite these harsh conditions, the phototrophic microbial community was unexpectedly diverse. Preliminary attempts to isolate and identify oxygenic phototrophs from SPNWR water and soil samples yielded 47 species from 20 taxa and 3 divisions. Our data indicate that highly variable, extreme environments might support phototrophic microbial communities characterized by higher species diversity than previously assumed.

Laboratory investigations of trichomycete prevalence, abundance and fecundity in a Smittium-simuliid model.

Smittium, the most speciose genus of the "gut fungi" (Zygomycota: Trichomycetes), is found attached to the hindgut cuticle of larval aquatic Diptera. Smittium spp. colonize several host families (e.g., Smittium culisetae in Chironomidae, Culicidae and Simuliidae), but some species appear to be specific to a single host family (e.g., Smittium morbosum Sweeney in Culicidae). The specificity of Smittium spp. within a host family has been difficult to resolve. This research presents evidence that certain Smittium spp. differentially colonize particular species of black fly (Diptera: Simuliidae) hosts as measured by differences in prevalence, abundance and fecundity. Reasons for this differential occurrence and fecundity in hosts are unclear but might include fungal responses to variations in host morphology, physiology, distribution or behavior. Variable fitness of Smittium spp., within a suite of available hosts, could be a factor in the diversity of this fungal group.

First report of a trichomycete fungus (Zygomycota: Trichomycetes) inhabiting larvae of Simulium ochraceum sensu lato Walker (Diptera: Simuliidae) from the Galapagos Islands.

A collection of the larval black fly Simulium ochraceum sensu lato Walker was made at six lotic habitats on San Cristobal Island, Galapagos Islands, Ecuador, during May 2003. Sixty-eight larvae were assayed for the presence of gut fungi (Zygomycota: Trichomycetes). A trichomycete, designated as Smittium sp. was found inhabiting the hindgut of 17.6% of S. ochraceum s.l. larvae. Implications of this finding with respect to both host and trichomycete biogeography are discussed.

Prevalence of the trichomycete fungus Harpella melusinae (Harpellales: Harpellaceae) in larval black flies (Diptera: Simuliidae) across a heterogeneous environment.

A total of 2063 mid- to late-instar larval black flies were collected from 64 stream sites in South Carolina and screened for the presence of the trichomycete fungus Harpella melusinae. Sixteen of 18 host species were colonized by H. melusinae on at least one occasion. Prevalence of H. melusinae in larvae of Simulium tuberosum cytospecies "A" was highest in acidic streams with low conductivity, whereas H. melusinae colonized larvae of Simulium verecundum most frequently in slower-moving streams. Ecological conditions, therefore, can serve as predictors of the prevalence of H. melusinae. Prevalence in host larvae was significantly lower in the Piedmont ecoregion than in the Mountain ecoregion. Prevalence did not differ in the host species S. verecundum across ecoregions, suggesting that different prevalences among host species might indicate some host preference. The prevalence of H. melusinae differed significantly between two univoltine host species (Simulium venustum and Prosimulium magnum) at the same site but not between two multivoltine host species (S. tuberosum cytospecies "FG" and S. tuberosum cytospecies "CDE"), suggesting that host life history could be important in determining fungal prevalence.

The microdistribution of the trichomycete Smittium culisetae in the hindgut of the black fly host Simulium vittatum.

We examined the distribution of hyphae of the trichomycete fungus Smittium culisetae (Harpellales: Legeriomycetaceae) in the hindgut of a larval black fly (Simulium vittatum, cytospecies IS-7) by analyzing its prevalence and relative abundance. Hyphal prevalence was highest in the posterior colon (93.1%) and rectum (86.3%), with low prevalence (12.0%) in the anterior colon. Relative abundance of hyphae was highest in the posterior colon, followed by the rectum; relative abundance of hyphae in the anterior colon was lower. Hyphae of S. culisetae were not observed in the pylorus. We used a novel method of quantifying the relative abundance of S. culisetae in the host hindgut. The hindgut was observed with an ocular grid, and abundance was expressed as the ratio of grids occupied by hyphae to the number of grids occupied by hindgut.