Simplifying understory complexity in oil palm plantations is associated with a reduction in the density of a cleptoparasitic spider,Argyrodes miniaceus (Araneae: Theridiidae), in host (Araneae: Nephilinae) webs

Expansion of oil palm agriculture is currently one of the main drivers of habitat modification in Southeast Asia. Habitat modification can have significant effects on biodiversity, ecosystem function, and interactions between species by altering species abundances or the available resources in an ecosystem. Increasing complexity within modified habitats has the potential to maintain biodiversity and preserve species interactions. We investigated trophic interactions between Argyrodes miniaceus, a cleptoparasitic spider, and its Nephila spp. spider hosts in mature oil palm plantations in Sumatra, Indonesia. A. miniaceus co‐occupy the webs of Nephila spp. females and survive by stealing prey items caught in the web. We examined the effects of experimentally manipulated understory vegetation complexity on the density and abundance of A. miniaceus in Nephila spp. webs. Experimental understory treatments included enhanced complexity, standard complexity, and reduced complexity understory vegetation, which had been established as part of the ongoing Biodiversity and Ecosystem Function in Tropical Agriculture (BEFTA) Project. A. miniaceus density ranged from 14.4 to 31.4 spiders per square meter of web, with significantly lower densities found in reduced vegetation complexity treatments compared with both enhanced and standard treatment plots. A. miniaceus abundance per plot was also significantly lower in reduced complexity than in standard and enhanced complexity plots. Synthesis and applications: Maintenance of understory vegetation complexity contributes to the preservation of spider host–cleptoparasite relationships in oil palm plantations. Understory structural complexity in these simplified agroecosystems therefore helps to support abundant spider populations, a functionally important taxon in agricultural landscapes. In addition, management for more structurally complex agricultural habitats can support more complex trophic interactions in tropical agroecosystems.     

High levels of genetic structure and striking phenotypic variability in a sexually dimorphic suckermouth catfish from the African Highveld

Uncovering biological diversity to more accurately understand diversity patterns, and ultimately the processes driving diversification, is important not only from an evolutionary perspective but also a conservation perspective. This is particularly pertinent in Africa's rivers in which overall diversity, as well as how it arose, is poorly understood in comparison with lacustrine environments. Here we investigate population divergence in the sexually dimorphic suckermouth catfish species Chiloglanis anoterus (Crass, 1960) from the African Highveld, in which we observe striking variability in exaggerated male caudal fins across its range. As this trait is likely to be indirect evidence for sexual selection by female choice, a mechanism that has been shown to increase species diversity in different taxa, we used an integrated approach to test if current diversity in this species is underestimated. Results based on phylogenetic inference, population genetics and geometric morphometrics indicate that the recognized species C. anoterus represents five distinct lineages that may be considered confirmed candidate species. We suggest that diversification in these highland catfish has been facilitated through geographical isolation in upper river catchments, and that sexual selection through female choice has probably driven variation in male caudal fin morphology. In contrast to the relatively large range size of the currently recognized species (C. anoterus), our findings highlight highly restricted ranges of the lineages identified here, indicating that these highland habitats may harbour higher levels of endemic diversity than previously thought.     

The methodology and results of using life cycle assessment to measure and reduce the greenhouse gas emissions footprint of “Major Events” at the University of Arizona

Purpose

In 2012 and 2013, the University of Arizona’s Office of Sustainability conducted environmental life cycle assessments of two Homecoming events that drew 60,000 attendees each. Based on reviews of published literature, this is the first time that a process-based life cycle assessment has been conducted for an event of this size. This study contributes to the small but growing field of research using life cycle assessment to track the environmental impacts of events.

Methods

The assessments at The University of Arizona considered the environmental impact of food, materials, waste, travel, and lodging. The effects of these components of Homecoming weekend were evaluated in terms of nine different categories. However, this paper focuses on greenhouse gas emissions. The data collection process for these assessments was completed by student observers and supplemented with information provided by university departments, event organizers, and survey responses from attendees. Data were analyzed using SimaPro Life Cycle Assessment software and using data from the EcoInvent database. Based on the results of the 2012 study, initiatives were put into place for 2013 that were designed to reduce the environmental impact of the subsequent Homecoming event.

Results and discussion

The results show that the total impact of Homecoming 2012 was an estimated 2400 metric tons of CO₂-eq, whereas the impact of Homecoming 2013 was an estimated 1900 metric tons of CO₂-eq, a 19 % decrease year over year. Data were analyzed in terms of carbon dioxide emissions in both years. Travel made up the majority of the environmental impact (82.04 % in 2012 and 77.77 % in 2013), followed by accommodations (17.5 % in 2012 and 19.31 % in 2013), with energy, materials, and food having almost negligible impacts (0.46 % in 2012 and 2.92 % in 2013). While there had been noticeable changes in the measured impact of food and energy between 2012 and 2013, the significant impact of travel overshadowed all other impact categories in terms of greenhouse gas emissions, making these changes less noticeable. Analysis of each of these categories of impact helped to establish best practices for mitigating the impact of events on a category-by-category basis.

Conclusions

This study introduces a framework for assessing impacts of a large university event while also highlighting ways to reduce impacts. The initiatives implemented in 2013 to reduce impacts of large-scale events can be informative to others working to reduce emissions at large events. Additional recommendations to reduce impacts of large events are provided.

     

Limited Protection from a Pathogenic Chimeric Simian-Human Immunodeficiency Virus Challenge following Immunization with Attenuated Simian Immunodeficiency Virus

Two live attenuated single-deletion mutant simian immunodeficiency virus (SIV) constructs, SIV_239Δnef and SIV_PBj6.6Δnef, were tested for their abilities to stimulate protective immunity in macaques. During the immunization period the animals were examined for specific immune responses and virus growth. Each construct generated high levels of specific immunity in all of the immunized animals. The SIV_239Δnef construct was found to grow to high levels in all immunized animals, with some animals remaining positive for virus isolation and plasma RNA throughout the immunization period. The SIV_PBj6.6Δnef was effectively controlled by all of the immunized animals, with virus mostly isolated only during the first few months following immunization and plasma RNA never detected. Following an extended period of immunization of over 80 weeks, the animals were challenged with a pathogenic simian-human immunodeficiency virus (SHIV) isolate, SIV_89.6PD, by intravenous injection. All of the SIV_239Δnef-immunized animals became infected with the SHIV isolate; two of five animals eventually controlled the challenge and three of five animals, which failed to check the immunizing virus, progressed to disease state before the unvaccinated controls. One of five animals immunized with SIV_PBj6.6Δnef totally resisted infection by the challenge virus, while three others limited its growth and the remaining animal became persistently infected and eventually died of a pulmonary thrombus. These data indicate that vaccination with attenuated SIV can protect macaques from disease and in some cases from infection by a divergent SHIV. However, if animals are unable to control the immunizing virus, potential damage that can accelerate the disease course of a pathogenic challenge virus may occur.     

Positive Maternal Attitude to the Family Eating Together Decreases the Risk of Adolescent Overweight

Objectives: To determine whether maternal attitude towards the family regularly eating together and maternal report of how often the family eat together are associated with adolescent offspring overweight. Research Methods and Procedures: A cross‐sectional mother‐child‐linked analysis was carried out using 14‐year follow‐up data from a population‐based prospective birth cohort of 3795 children (52% males) who were participants in the Mater‐University study of pregnancy, Brisbane, Australia. Maternal reports on family eating pattern reported at age 14 were used. Results: The prevalence of overweight at age 14 was 24.1% (95% confidence interval (CI), 22.3, 26.1) for males and 27.1% (CI, 25.1, 29.2) for females. The majority of mothers (78%) reported that the family ate together at least once a day, but only 43% reported that they felt that family eating together was important. The offspring of women who felt that the family eating together was not important had increased odds of being overweight at age 14 (odds ratio, 1.27; 95% CI, 1.05, 1.53) in age‐ and sex‐adjusted models. Adjustment for potential confounding factors had no substantive effect on the association. There was no association between maternal reports of how often the family actually did eat together and overweight at age 14 in the offspring. Discussion: These findings suggest that maternal attitude towards family eating patterns, but not maternal report of how often the family do eat together, are associated with childhood overweight status. Maternal attitude towards family eating (as opposed to a report of actual frequency at one time‐point) may reflect broader maternal influences (beyond family eating pattern) on their child's diet and eating patterns over a long time course.     

Setting clock speed in mammals: the CK1 epsilon tau mutation in mice accelerates circadian pacemakers by selectively destabilizing PERIOD proteins

The intrinsic period of circadian clocks is their defining adaptive property. To identify the biochemical mechanisms whereby casein kinase1 (CK1) determines circadian period in mammals, we created mouse null and tau mutants of Ck1 epsilon. Circadian period lengthened in CK1epsilon-/-, whereas CK1epsilon(tau/tau) shortened circadian period of behavior in vivo and suprachiasmatic nucleus firing rates in vitro, by accelerating PERIOD-dependent molecular feedback loops. CK1epsilon(tau/tau) also accelerated molecular oscillations in peripheral tissues, revealing its global role in circadian pacemaking. CK1epsilon(tau) acted by promoting degradation of both nuclear and cytoplasmic PERIOD, but not CRYPTOCHROME, proteins. Together, these whole-animal and biochemical studies explain how tau, as a gain-of-function mutation, acts at a specific circadian phase to promote degradation of PERIOD proteins and thereby accelerate the mammalian clockwork in brain and periphery.     

Semidominant mutations in reduced epidermal fluorescence 4 reduce phenylpropanoid content in Arabidopsis

Plants synthesize an array of natural products that play diverse roles in growth, development, and defense. The plant-specific phenylpropanoid metabolic pathway produces as some of its major products flavonoids, monolignols, and hydroxycinnamic- acid conjugates. The reduced epidermal fluorescence 4 (ref4) mutant is partially dwarfed and accumulates reduced quantities of all phenylpropanoid-pathway end products. Further, plants heterozygous for ref4 exhibit intermediate growth and phenylpropanoid-related phenotypes, suggesting that these mutations are semidominant. The REF4 locus (At2g48110) was cloned by a combined map- and sequencing-based approach and was found to encode a large integral membrane protein that is unique to plants. The mutations in all ref4 alleles cause substitutions in conserved amino acids that are located adjacent to predicted transmembrane regions. Expression of the ref4-3 allele in wild-type and null REF4 plants caused reductions in sinapoylmalate content, lignin content, and growth, demonstrating that the mutant alleles are truly semidominant. Further, a suppressor mutant was isolated that abolishes a WW protein-protein interaction domain that may be important for REF4 function.     

Molecular genetics and comparative genomics reveal RNAi is not functional in malaria parasites

Techniques for targeted genetic disruption in Plasmodium, the causative agent of malaria, are currently intractable for those genes that are essential for blood stage development. The ability to use RNA interference (RNAi) to silence gene expression would provide a powerful means to gain valuable insight into the pathogenic blood stages but its functionality in Plasmodium remains controversial. Here we have used various RNA-based gene silencing approaches to test the utility of RNAi in malaria parasites and have undertaken an extensive comparative genomics search using profile hidden Markov models to clarify whether RNAi machinery exists in malaria. These investigative approaches revealed that Plasmodium lacks the enzymology required for RNAi-based ablation of gene expression and indeed no experimental evidence for RNAi was observed. In its absence, the most likely explanations for previously reported RNAi-mediated knockdown are either the general toxicity of introduced RNA (with global down-regulation of gene expression) or a specific antisense effect mechanistically distinct from RNAi, which will need systematic analysis if it is to be of use as a molecular genetic tool for malaria parasites.