Terrestrial arthropod community and indicators of biotic integrity for Iowa tallgrass prairie

The tallgrass prairie has become one of the most endangered ecosystems in North America. Thus, there have been attempts to restore and reconstruct native tallgrass prairie. Arthropods, the most diverse taxonomic group on the prairie, have not received adequate attention. A comprehensive arthropod survey in Iowa prairies has not been attempted since the 1930\u27s, and therefore lacks information regarding recent prairie restoration efforts. Arthropods can also provide valuable information related to ecosystem function or biotic integrity when used as bioindicators. However, effective, reliable arthropod bioindicators have not been clearly identified. A survey of arthropods using sweep net transects was conducted on a cross-section of Iowa prairies among three prairie types: remnants, isolated restorations/reconstructions and landscape-scale integrated reconstructions. We compared the arthropod community across sampling years, sites, and site types. We used Indicator Species Analysis to identify families of insects and spiders that could be used as indicators of biotic integrity or restoration success. Arthropod communities differed slightly between years, and between prairie types. Convergence among prairies of different anthropogenic types may mean restoration efforts have been successful for the establishment of the native arthropod community. Alternatively, decades of human disturbance at the regional scale may have reduced or eliminated prairie restricted taxa. Both of these explanations may actually be accurate. Four insect families and one spider family were identified as indicators of remnant prairies, with additional taxa demonstrating some affinity to remnant sites. Indicator taxa we identified provide further support for previously identified indicators, such as ants (Formicidae), but also include taxa not previously recorded as prairie bioindicators

Effects of Echinostoma trivolvis metacercariae infection during development and metamorphosis of the wood frog (Lithobates sylvaticus)

Many organisms face energetic trade-offs between defense against parasites and other host processes that may determine overall consequences of infection. These trade-offs may be particularly evident during unfavorable environmental conditions or energetically demanding life history stages. Amphibian metamorphosis, an ecologically important developmental period, is associated with drastic morphological and physiological changes and substantial energetic costs. Effects of the trematode parasite Echinostoma trivolvis have been documented during early amphibian development, but effects during later development and metamorphosis are largely unknown. Using a laboratory experiment, we examined the energetic costs of late development and metamorphosis coupled with E. trivolvis infection in wood frogs, Lithobates [=Rana] sylvaticus. Echinostoma infection intensity did not differ between tadpoles examined prior to and after completing metamorphosis, suggesting that metacercariae were retained through metamorphosis. Infection with E. trivolvis contributed to a slower growth rate and longer development period prior to the initiation of metamorphosis. In contrast, E. trivolvis infection did not affect energy expenditure during late development or metamorphosis. Possible explanations for these results include the presence of parasites not interfering with pronephros degradation during metamorphosis or the mesonephros compensating for any parasite damage. Overall, the energetic costs of metamorphosis for wood frogs were comparable to other species with similar life history traits, but differed from a species with a much shorter duration of metamorphic climax. Our findings contribute to understanding the possible role of energetic trade-offs between parasite defense and host processes by considering parasite infection with simultaneous energetic demands during a sensitive period of development

The Effects of Fluorescent Tracking Powder on Oxygen Consumption in Salamanders Using Either Cutaneous or Bimodal Respiration

Fluorescent powder is gaining attention as an effective method for tracking terrestrial amphibian movements, particularly for species that are too small for conventional tracking equipment. The technique requires coating portions of an animal with fluorescent powder, releasing the animal, and following the trail of powder as it is progressively lost during movement. Recent studies have shown that fluorescent powder has no negative effects on survival or growth. However, a substance that coats the skin, a major respiratory organ in most amphibians, may have sublethal effects on performance and consequently behavior. We tested the effect of fluorescent powder application on the respiration of lungless Red-Backed Salamanders, Plethodon cinereus, and lunged terrestrial Red-Spotted Newts, Notophtholmus viridescens. In comparing species with contrasting skin textures and primary modes of respiration, we expected to find P. cinereus, the species relying solely on cutaneous respiration, more sensitive to fluorescent powder. Standard metabolic rate (SMR) and total oxygen consumption for both species were measured before and after application of the powder. We found no significant differences in respiration between control and powdered salamanders. Independent of treatment, SMR was 6-16% higher during the post-treatment trial in both species, and likewise, total oxygen consumed increased by 8-20% in P. cinereus and by 7-10% in N. viridescens. Our results, in combination with other recent work, suggest that fluorescent powder is a safe technique for tracking amphibians

Experimental investigation of alternative transmission functions: quantitative evidence for the importance of non-linear transmission dynamics in host-parasite systems

1. Understanding pathogen transmission is crucial for predicting and managing disease. Nonetheless, experimental comparisons of alternative functional forms of transmission remain rare, and those experiments that are conducted are often not designed to test the full range of possible forms. 2. To differentiate among 10 candidate transmission functions, we used a novel experimental design in which we independently varied four factors—duration of exposure, numbers of parasites, numbers of hosts and parasite density—in laboratory infection experiments. 3. We used interactions between amphibian hosts and trematode parasites as a model system and all candidate models incorporated parasite depletion. An additional manipulation involving anaesthesia addressed the effects of host behaviour on transmission form. 4. Across all experiments, nonlinear transmission forms involving either a power law or a negative binomial function were the best‐fitting models and consistently outperformed the linear density‐dependent and density‐independent functions. By testing previously published data for two other host–macroparasite systems, we also found support for the same nonlinear transmission forms. 5. Although manipulations of parasite density are common in transmission studies, the comprehensive set of variables tested in our experiments revealed that variation in density alone was least likely to differentiate among competing transmission functions. Across host–pathogen systems, nonlinear functions may often more accurately represent transmission dynamics and thus provide more realistic predictions for infection

Towards the automated identification of Chrysomya blow flies from wing images

This is the pre-peer reviewed version of the following article: Macleod, N. , Hall, M. J. and Wardhana, A. H. (2018), Towards the automated identification of Chrysomya blow flies from wing images. Med Vet Entomol. . doi:10.1111/mve.12302, which has been published in final form at https://doi.org/10.1111/mve.12302. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving

A new vine snake (Reptilia, Colubridae, Oxybelis) from Peru and redescription of O. acuminatus

The Brown Vine Snake, Oxybelis aeneus, was until recently considered a single species, distributed from southern Arizona through the Neotropics into southeastern Brazil. However, newly conducted research restructured the species with a substantial taxonomic revision, recognizing five additional taxa (i.e. O. koehleri, O. microphthalmus, O. potosiensis, O. rutherfordi, O. vittatus) in this species complex. This revision focused on populations in North America, Central America, and northern South America while neglecting the southern portion of its distribution. Here, we examine the taxonomic history of the complex and use it along with specimen data to resurrect O. acuminatus from southeastern Brazil. Finally, we describe a new species from the Peruvian Amazon based on morphological characters. This work increases the species diversity of the O. aeneus complex to eight, and we expect further increases in biodiversity discoveries with continued exploration of the New World vine snakes

The evolutionary ecology of complex lifecycle parasites: linking phenomena with mechanisms

Many parasitic infections, including those of humans, are caused by complex lifecycle parasites (CLPs): parasites that sequentially infect different hosts over the course of their lifecycle. CLPs come from a wide range of taxonomic groups-from single-celled bacteria to multicellular flatworms-yet share many common features in their life histories. Theory tells us when CLPs should be favoured by selection, but more empirical studies are required in order to quantify the costs and benefits of having a complex lifecycle, especially in parasites that facultatively vary their lifecycle complexity. In this article, we identify ecological conditions that favour CLPs over their simple lifecycle counterparts and highlight how a complex lifecycle can alter transmission rate and trade-offs between growth and reproduction. We show that CLPs participate in dynamic host-parasite coevolution, as more mobile hosts can fuel CLP adaptation to less mobile hosts. Then, we argue that a more general understanding of the evolutionary ecology of CLPs is essential for the development of effective frameworks to manage the many diseases they cause. More research is needed identifying the genetics of infection mechanisms used by CLPs, particularly into the role of gene duplication and neofunctionalisation in lifecycle evolution. We propose that testing for signatures of selection in infection genes will reveal much about how and when complex lifecycles evolved, and will help quantify complex patterns of coevolution between CLPs and their various hosts. Finally, we emphasise four key areas where new research approaches will provide fertile opportunities to advance this field