New ostracod species (Cypridopsis schwartzi n. sp.) from Texas, with discussion on the taxonomic status of Cypridopsis species in the USA.

A total of 39 taxa (19 living species, 20 subfossils) were collected from 59 different shallow aquatic bodies in Texas during April to June 2017. Cypridopsis schwartzi n. sp.

Ecological dependencies make remote reef fish communities most vulnerable to coral loss.

Ecosystems face both local hazards, such as over-exploitation, and global hazards, such as climate change. Since the impact of local hazards attenuates with distance from humans, local extinction risk should decrease with remoteness, making faraway areas safe havens for biodiversity. However, isolation and reduced anthropogenic disturbance may increase ecological specialization in remote communities, and hence their vulnerability to secondary effects of diversity loss propagating through networks of interacting species.

The prevalence of Leptospira among invasive small mammals on Puerto Rican cattle farms.

Leptospirosis, an emerging infectious disease caused by bacteria of the genus Leptospira, is thought to be the most widespread zoonotic disease in the world. A first step in preventing the spread of Leptospira is delineating the animal reservoirs that maintain and disperse the bacteria. Quantitative PCR (qPCR) methods targeting the LipL32 gene were used to analyze kidney samples from 124 House mice (Mus musculus), 94 Black rats (Rattus rattus), 5 Norway rats (R.

Modular structure in fish co-occurrence networks: A comparison across spatial scales and grouping methodologies.

Network modules are used for diverse purposes, ranging from delineation of biogeographical provinces to the study of biotic interactions. We assess spatial scaling effects on modular structure, using a multi-step process to compare fish co-occurrence networks at three nested scales. We first detect modules with simulated annealing and use spatial clustering tests (interspecific distances among species' range centroids) to determine if modules consist of species with broadly overlapping ranges; strong spatial clustering may reflect environmental filtering, while absence of spatial clustering may reflect positive interspecific relationships (commensalism or mutualism).

Forbidden versus permitted interactions: Disentangling processes from patterns in ecological network analysis.

Several studies have identified the tendency for species to share interacting partners as a key property to the functioning and stability of ecological networks. However, assessing this pattern has proved challenging in several regards, such as finding proper metrics to assess node overlap (sharing), and using robust null modeling to disentangle significance from randomness. Here, we bring attention to an additional, largely neglected challenge in assessing species' tendency to share interacting partners.

Far from Naturalness: How Much Does Spatial Ecological Structure of European Tree Assemblages Depart from Potential Natural Vegetation?

Contemporaneous plant communities may retain a mark of past disturbances in their ecological patterns. However, unraveling the history of disturbance on natural systems at a large scale is often unfeasible, due to the complexity of the factors involved and lack of historical data. Here we aim at demonstrating how comparing observed spatial structure of tree assemblages with that expected in a hypothetical, undisturbed scenario can shed light on how natural European forests are.

Diversity partitioning without statistical independence of alpha and beta.

Diversity partitioning has become a popular method for analyzing patterns of alpha and beta diversity. A recent evaluation of the method emphasized a distinction between additive and multiplicative partitioning and further advocated the use of multiplicative partitioning based on a presumed independence between alpha and beta. Concurrently, additive partitioning was criticized for producing dependent alpha and beta estimates.

A comparison of landscapes occupied by increasing and decreasing populations of grassland birds.

For several decades, many grassland bird species have been declining in abundance throughout the Midwest and Great Plains regions of the United States, possibly due to loss of natural grassland habitat and increasing urbanization. I used 20 years of data from the North American Breeding Bird Survey to identify increasing, decreasing, and stable populations of 36 grassland-nesting bird species. I characterized the immediate landscape (circle with radius = 30 km) surrounding each population based on data from the National Resources Inventory.

Additive partitioning of rarefaction curves and species-area relationships: unifying alpha-, beta- and gamma-diversity with sample size and habitat area.

Additive partitioning of species diversity is widely applicable to different kinds of sampling regimes at multiple spatial and temporal scales. In additive partitioning, the diversity within and among samples (alpha and beta) is expressed in the same units of species richness, thus allowing direct comparison of alpha and beta. Despite its broad applicability, there are few demonstrated linkages between additive partitioning and other approaches to analysing diversity.

Partitioning species diversity across landscapes and regions: a hierarchical analysis of alpha, beta, and gamma diversity.

Species diversity may be additively partitioned within and among samples (alpha and beta diversity) from hierarchically scaled studies to assess the proportion of the total diversity (gamma) found in different habitats, landscapes, or regions. We developed a statistical approach for testing null hypotheses that observed partitions of species richness or diversity indices differed from those expected by chance, and we illustrate these tests using data from a hierarchical study of forest-canopy beetles. Two null hypotheses were implemented using individual- and sample-based randomization tests to generate null distributions for alpha and beta components of diversity at multiple sampling scales.

Predator-mediated interactions among the seeds of desert plants.

In theory, seed predators are capable of inducing indirect interactions among the seeds they consume. However, empirical evidence of predator-mediated interactions among seeds is rare. Rodents in the Heteromyidae are highly granivorous and therefore likely to induce indirect interactions among the seeds of desert plants.

Cheek pouch capacities and loading rates of heteromyid rodents.

Rodents of the family Heteromyidae are proficient gatherers and hoarders of seeds. A major component of their adaptive specialization for harvesting and transporting seeds is their spacious, fur-lined cheek pouches. Precise measurements of cheek pouch capacities are essential if ecologists are to understand the foraging ecology, possible constraints on locomotion patterns, and competitive relationships of heteromyid rodents.

LACK OF CALLING SONG DISPLACEMENT BETWEEN TWO CLOSELY RELATED GROUND CRICKETS.

Thorough examinations of purported cases of reproductive character displacement are critical for reaching an understanding of the role of reinforcement in the evolution of reproductive barriers between closely related species. In this paper, we report the results of an extensive investigation of male calling song variation in the ground crickets, Allonemobius fasciatus and A. socius.

Reproduction of Four Races of Meloidogyne incognita on Hibiscus cannabinus.

The feasibility of cultivation of kenaf (Hibiscus cannabinus) in the United States is receiving a multifaceted evaluation. Among the factors being evaluated is kenafs susceptibility to nematodes. In this investigation, four races of Meloidogyne incognita reproduced extensively on each of the several kenaf genotypes examined in greenhouse tests.

Counting nematodes with a microplate reader.

The feasibility of counting plant-parasitic nematodes in aqueous suspensions by measuring light transmittance through aqueous suspensions with an ELISA microplate reader was explored. Absorbance readings for eggs or vermiform stages of three species were linearly related (R(2) > 0.99) to concentrations between 0 and 10,000 nematodes/ml.

Collapse of intercellular spaces of canine tracheal mucosa by epinephrine.

Variations in the volume and width of lateral intercellular spaces (LICS) of dog tracheal mucosa in vitro were investigated by use of stereological and linear measurements of electron micrographs. Alterations in the volume or width of LICS were then correlated with physiological conditions and electrical parameters. LICS were quite narrow between the ciliated cells compared with those around the nonciliated dark cells (goblet, brush, and basal cells).

Production and Partial Characterization of Stylet Exudate from Adult Females of Meloidogyne incognita.

Adult females of Meloidogyne incognita were excised from tomato roots and incubated in 0.04 M phosphate buffered saline, pH 7.4 for 18-72 hours to allow accumulation of stylet exudate.

Phytoalexins and their Role in the Resistance of Plants to Nematodes.

Phytoalexins are antibiotic compounds synthesized in an infected plant in response to infection. Nematodes are capable of eliciting phytoalexins in resistant plants. Resistant lima bean (Phaseolus lunatus) infected by Pratylenchus penetrans produces the phytoalexin coumestrol; soybean (Glycine max) infected by Meloidogyne incognita produces glyceollin; cotton (Gossypium hirsuturn) infected by M.

Histochemical localization and nematoxicity of terpenoid aldehydes in cotton.

In healthy cotton, except for random occasional occurrence in cortical cells, terpenoid aldehydes (TA) are localized in the epidermis and, even there, are absent from the tip 2-4 cm of the root. Since constitutive TA do not occur in the endodermis and stele of the root, they cannot be effective agents against the development of the sedentary stage of the root-knot nematode, Meloidogyne incognita. Within 4 days after inoculation with the root-knot nematode, infection-induced TA accumulated in the endodermis and outer stele.

Terpenoid aldehydes in cotton roots susceptible and resistant to the root-knot nematode, Meloidogyne incognita.

We investigated the role of terpenoid aldehydes in the resistance of cotton (Gossypium hirsutum) to the root-knot nematode (Meloidogyne incognita). Three-day-old, root-knot-resistant ('Auburn 623') and -susceptible ('Deltapine 16') seedlings were inoculated with M. incognita.