Weight watching in burrows: variation in body condition in pygmy bluetongue lizards

Author version made available in accordance with the publisher's policyThe pygmy bluetongue lizard, Tiliqua adelaidensis, is an endangered scincid lizard which occurs in remnants of natural grasslands in the mid-north of South Australia. We assessed the factors affecting body condition of male and female lizards, using body size residuals as an index, over five sampling years. We included sex, phenotypic (patterned or plain morphs), temporal (sampling year and activity period within year), and climatic factors in our analyses. The results indicated that sampling year and activity period within the year were the two most important factors influencing variation in body condition of both male and female lizards over the period of the study. There were similar trends when we considered females separately in each of three stages of their reproductive cycle (pre-partum, gravid, post-partum). None of the analyses showed any significant effect of phenotype on body condition. Winter-spring rainfall was positively correlated with body condition of females in the pre-partum period, but showed no significant effect on mean body condition of any other grouping of adult lizards, nor a consistent direction of correlation among the different subsets of adult lizards that we considered. The substantial annual variations in the body condition of lizards, although of uncertain cause, provide important information for conservation managers who monitor persisting populations of this endangered species

Interactions between pygmy bluetongue lizards and co-existing species

This is an Accepted Manuscript of an article published by Taylor & Francis in TRANSACTIONS OF THE ROYAL SOCIETY OF SOUTH AUSTRALIA on 14 June 2015, available online: http://www.tandfonline.com/10.1080/03721426.2015.1051644. This author version will be under embargo for a period of 12 months from the date of publicationThis paper describes observations of interactions between endangered pygmy bluetongue lizards (Tiliqua adelaidensis) and other species that co-occur in their native grassland habitat in the mid-north region of South Australia. The lizard lives in spider burrows, and rarely moves away from the burrow entrance. We viewed over 16,000 h of video recording of occupied pygmy bluetongue lizard burrows, taken over five 10 day periods throughout one complete lizard activity season, and documented all cases in which these endangered lizards interacted with co-existing species. We found that these interactions were infrequent. We observed potential competition over burrow resources with lycosid spiders (Lycosa spp), centipedes, and a house mouse, and potential competition over invertebrate prey with a predatory wasp. We also observed unsuccessful predation attempts on lizards in burrows by ravens and brown snakes. We suggest that conservation management might have proceeded effectively without this information, but that it provides useful background information for informed decision making

Variation in size and condition of neonate pygmy bluetongue lizards, Tiliqua adelaidensis

This is an Accepted Manuscript of an article published by Taylor & Francis in TRANSACTIONS OF THE ROYAL SOCIETY OF SOUTH AUSTRALIA on 9 June 2015, available online: http://www.tandfonline.com/10.1080/03721426.2015.1045312. This item is under embargo for a period of 12 months from the date of publicationPhenotypic variation among offspring of individual animals is an important life-history trait. In viviparous lizards, it could result from genetic variation of individuals and also differences in environments experienced by mothers during gestation. We investigated variation in phenotype and survival of neonate pygmy bluetongue lizards, Tiliqua adelaidensis, over three sampling years. We explored changes in body condition, using body size residuals as an index, and body size (snout-vent length (SVL) and mass) of neonates. For litters that were captured with their mothers, we hypothesised that body condition and size of offspring are influenced by the condition and size of their mothers, presence of mothers in the burrow and litter size. We found that there were significant variations in body condition and mass of neonates among years. There was no significant relationship between neonate body condition, mass and SVL and post-partum body condition of their mothers. Results revealed that females with higher SVL produced larger litters. None of the analyses showed any effect of mother’s presence on neonate body condition, SVL or mass. Neither was there any effect of observed litter size on these parameters. Our findings have important conservation implications for this endangered species, given that the aim of conservation managers is to encourage conditions that promote optimum body condition and fitness in offspring in order to maximise their survival in fragmented habitats

Dynamics of a temperate grassland reptile community in the mid-north of South Australia

Published version of the paper reproduced here with permission from the Royal Society of South Australia.Temperate native grasslands are listed as a critically endangered ecological community in South Australia, yet very little is known about the associated faunal communities. This study aims to provide information on the temporal dynamics of a native grassland reptile community in the mid-north of South Australia. During the study we made 335 reptile captures in pitfall traps, of 248 different individuals, from 13 species, representing five families. These data were used to investigate seasonal trends in trapping rate, age demographics and movement of individuals from marked recaptures. The results of the study provide baseline information on species assemblages that might be used in the recovery and management of the remaining fragments of temperate native grasslands and the endangered pygmy bluetongue lizard that relies on those fragments for its persistence.This research was supported by funds from the Australian Research Council

Promiscuous mating in the endangered Australian lizard Tiliqua adelaidensis: a potential windfall for its conservation

Author version made available in accordance with the Publisher's policy. The final publication is available at Springer via http://dx.doi.org/10.1007/s10592-013-0529-0Studies have revealed an unsuspected complexity in social systems within a few lizard species, including group living, long-term monogamy and individual recognition of partners or offspring. Comparisons among these species and their relatives could provide valuable insights, allowing us to investigate traits that are shared across social systems and identify general principles relating to the evolution of sociality. The endangered pygmy bluetongue lizard, Tiliqua adelaidensis, is a member species in the Egernia group, but is thought to show a more solitary social structure than other members in this group. Within this study we used microsatellite markers to determine the mating system of T. adelaidensis. Unlike many other species in the Egernia group, we found a predominately promiscuous mating system in T. adelaidensis. We detected multiple paternity in 75% of litters. Of the 70 males identified as having fathered juveniles, only five were identified as mating with the same female in more than one year and only three were identified as the father of juveniles with the same female in consecutive years. The genetic evidence suggested that partners were chosen randomly with respect to the level of relatedness among neighbouring lizards. However, mated lizards were geographically closer to each other than expected by random chance. Multiple paternities rely on the opportunity for males to encounter multiple females during the period when they are receptive to mating, and this may depend on population densities. Drivers for the polygamous mating system may be the single occupancy burrow and the central place territorial defence of those burrows in T. adelaidensis. We propose a fourth mating system for the Egernia group: polygyny within stable non-social colonies

Scatting behaviour of the sleepy lizard, Tiliqua rugosa

This is an Accepted Manuscript of an article published by Taylor & Francis in TRANSACTIONS OF THE ROYAL SOCIETY OF SOUTH AUSTRALIA on 28 July 2015, available online: http://www.tandfonline.com/10.1080/03721426.2015.1074341. This item is under embargo for a period of 12 months from the date of publication.The use of chemical signals for communication is wide spread in many animal taxa. Squamates in particular have a highly developed vomeronasal system and investigate chemical signals through tongue flicking. In some lizard species, individuals have been shown to be able use chemical signals, including those from faeces (scats), for discriminating between kin and conspecifics and members and non-members of social groups. The Australia scincid lineage Egernia, is one group that has an unusually high number of species reported to produce scat piles close to their refuge sights. In this paper we explore the scatting behaviour of the sleepy lizard, Tiliqua rugosa, a member of the Egernia lineage to determine whether there is any evidence of an aggregated deposition pattern of scats by this lizard, similar to other member species in the lineage. We found that unlike related species that appear to use scat piles as social markers, sleepy lizards do not deposit scats in any systematic latrine system, or in piles to indicate occupancy of an area. Rather, they appear to be scatting haphazardly inside their home range. A conclusion from this comparison is that scat piling in the Egernia lineage is associated more with refuge defence than with social aggregation

Scientific concepts and methods for moving persistence assessments into the 21st century

The evaluation of a chemical substance's persistence is key to understanding its environmental fate, exposure concentration, and, ultimately, environmental risk. Traditional biodegradation test methods were developed many years ago for soluble, nonvolatile, single-constituent test substances, which do not represent the wide range of manufactured chemical substances. In addition, the Organisation for Economic Co-operation and Development (OECD) screening and simulation test methods do not fully reflect the environmental conditions into which substances are released and, therefore, estimates of chemical degradation half-lives can be very uncertain and may misrepresent real environmental processes. In this paper, we address the challenges and limitations facing current test methods and the scientific advances that are helping to both understand and provide solutions to them. Some of these advancements include the following: (1) robust methods that provide a deeper understanding of microbial composition, diversity, and abundance to ensure consistency and/or interpret variability between tests; (2) benchmarking tools and reference substances that aid in persistence evaluations through comparison against substances with well-quantified degradation profiles; (3) analytical methods that allow quantification for parent and metabolites at environmentally relevant concentrations, and inform on test substance bioavailability, biochemical pathways, rates of primary versus overall degradation, and rates of metabolite formation and decay; (4) modeling tools that predict the likelihood of microbial biotransformation, as well as biochemical pathways; and (5) modeling approaches that allow for derivation of more generally applicable biotransformation rate constants, by accounting for physical and/or chemical processes and test system design when evaluating test data. We also identify that, while such advancements could improve the certainty and accuracy of persistence assessments, the mechanisms and processes by which they are translated into regulatory practice and development of new OECD test guidelines need improving and accelerating. Where uncertainty remains, holistic weight of evidence approaches may be required to accurately assess the persistence of chemicals. Integr Environ Assess Manag 2022;18:1454-1487. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC). Keywords: Bioavailability; Biodegradability; Biodegradation; Degradation half-lives; Persistence assessment

Scientific concepts and methods for moving persistence assessments into the 21st century

34 páginas.- 2 figuras.- 3 tablas.- 225 referenciasThe evaluation of a chemical substance's persistence is key to understanding its environmental fate, exposure concentration, and, ultimately, environmental risk. Traditional biodegradation test methods were developed many years ago for soluble, nonvolatile, single-constituent test substances, which do not represent the wide range of manufactured chemical substances. In addition, the Organisation for Economic Co-operation and Development (OECD) screening and simulation test methods do not fully reflect the environmental conditions into which substances are released and, therefore, estimates of chemical degradation half-lives can be very uncertain and may misrepresent real environmental processes. In this paper, we address the challenges and limitations facing current test methods and the scientific advances that are helping to both understand and provide solutions to them. Some of these advancements include the following: (1) robust methods that provide a deeper understanding of microbial composition, diversity, and abundance to ensure consistency and/or interpret variability between tests; (2) benchmarking tools and reference substances that aid in persistence evaluations through comparison against substances with well-quantified degradation profiles; (3) analytical methods that allow quantification for parent and metabolites at environmentally relevant concentrations, and inform on test substance bioavailability, biochemical pathways, rates of primary versus overall degradation, and rates of metabolite formation and decay; (4) modeling tools that predict the likelihood of microbial biotransformation, as well as biochemical pathways; and (5) modeling approaches that allow for derivation of more generally applicable biotransformation rate constants, by accounting for physical and/or chemical processes and test system design when evaluating test data. We also identify that, while such advancements could improve the certainty and accuracy of persistence assessments, the mechanisms and processes by which they are translated into regulatory practice and development of new OECD test guidelines need improving and accelerating. Where uncertainty remains, holistic weight of evidence approaches may be required to accurately assess the persistence of chemicals. Integr Environ Assess Manag 2022;1–34. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).Peer reviewe

Tuberculosis and HIV Co-Infection

Tuberculosis (TB) and HIV co-infections place an immense burden on health care systems and pose particular diagnostic and therapeutic challenges. Infection with HIV is the most powerful known risk factor predisposing for Mycobacterium tuberculosis infection and progression to active disease, which increases the risk of latent TB reactivation 20-fold. TB is also the most common cause of AIDS-related death. Thus, M. tuberculosis and HIV act in synergy, accelerating the decline of immunological functions and leading to subsequent death if untreated. The mechanisms behind the breakdown of the immune defense of the co-infected individual are not well known. The aim of this review is to highlight immunological events that may accelerate the development of one of the two diseases in the presence of the co-infecting organism. We also review possible animal models for studies of the interaction of the two pathogens, and describe gaps in knowledge and needs for future studies to develop preventive measures against the two diseases

A communal catalogue reveals Earth's multiscale microbial diversity

Our growing awareness of the microbial world's importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth's microbial diversity.Peer reviewe