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SUMMARYThe black nectar ofMelianthusflowers is thought to serve as a visual attractant to pollinators, but the chemical identity and synthesis of the black pigment are unknown. Here we report that the black nectar contains a natural analog of iron-gall ink, which humans have used since medieval times. Specifically, dark black nectar at anthesis contains high levels of ellagic acid and iron; synthetic solutions of ellagic acid and iron(III) recapitulate the black color of the nectar. Conversely, lightly colored nectars before and after anthesis contain significantly lower levels of ellagic acid and iron, but higher levels of gallic acid. We then explored the possibility of post-secretory synthesis of ellagic acid from gallic acid. Indeed,Melianthusnectar contains a peroxidase that oxidizes gallic acid to form ellagic acid. Reactions containing the nectar peroxidase, gallic acid, hydrogen peroxide, and iron can fully recreate the black color of the nectar. Visual modeling indicates that the black color is both visible and conspicuous to birds within the context of the flower. In summary, the black nectar ofMelianthusis derived from an ellagic acid-Fe complex analogous to iron-gall ink and is likely involved in the attraction of passerine bird pollinators.

The origin of novel communication systems has long been an evolutionary puzzle because communication requires interdependent signals and responses. Either component is not useful in isolation. Previous work has shown that novel communication systems may arise when pre-existing traits are co-opted for a novel function. However, research on developmental plasticity suggests we may benefit from considering how plasticity facilitates the origin and diversification of communication systems. In particular, plasticity can stabilize novel traits that are the first step towards signals or receiver responses (precursors) because plasticity allows individuals to rapidly adjust their phenotype based on their partner's phenotype, termed ‘reciprocal plasticity’. For example, exposure to a new sender precursor (e.g. new song) can produce a rapid, reciprocal change in receiver responses (e.g. preference for the new song). Reciprocal plasticity may facilitate the origin of new communication systems because precursors that influence conspecifics are more likely to become established signalling systems than precursors that are ignored by conspecifics. We review evidence that plasticity is important in the development and expression of a range of signals and preferences, the implications for divergence in signalling systems and its potential impacts on speciation and diversification. We outline areas of exciting future research, from incorporating more developmental realism into evolutionary models of signalling systems to using experimental evolution and novel anthropogenic environments to study genetic assimilation of plastic signals and preferences.

Developmental plasticity can alter the expression of sexual signals in novel environments and is therefore thought to play an important role in promoting divergence. Sexual signals, however, are often multimodal and mate choice multivariate. Hence, to understand how developmental plasticity can facilitate divergence, we must assess plasticity across signal components and its cumulative impact on signalling. Here, we examine how developmental plasticity influences different components of cabbage white butterfly Pieris rapae multimodal signals, its effects on their signalling phenotypes and its implications for divergence. To do this, we reared P. rapae caterpillars under two different light environments (low-light and high-light) to simulate conditions experienced by P. rapae colonizing a novel light habitat. We then examined plasticity in both visual (wing coloration) and olfactory (pheromone abundance) components of male sexual signals. We found light environments influenced expression of both visual and olfactory components and resulted in a trade-off between signal modalities. The ‘low-light’ phenotype had duller wing colours but higher abundance of the pheromone, indole, whereas the ‘high-light’ phenotype had comparatively brighter wings but lower abundance of indole. These results show that by simultaneously altering expression of different signal components, developmental plasticity can produce multiple signalling phenotypes, which may catalyse divergence.

Organismal tolerance to environmental pollution is thought to be constrained by fitness costs, where variants with higher survival in polluted environments have lower performance in nonpolluted environments. Yet, costs are not always detected in empirical studies. One hypothesis suggests that whether tolerance costs emerge depends on the degree of heterogeneity populations experience with respect to pollution exposure. For instance, in populations confined to local environments where pollution is persistent, selection may favour alleles that enhance pollution tolerance but reduce performance in nonpolluted environments (costs). However, in broadly distributed populations that undergo selection in both polluted and nonpolluted patches, costs should be eroded. Understanding tolerance costs in broadly distributed populations is relevant to management of invasive species, which are highly dispersive, wide ranging, and often colonize disturbed or polluted patches such as agricultural monocultures. Therefore, we conducted a case study quantifying costs of tolerance to zinc pollution (a common heavy metal pollutant) in wild cabbage white butterflies (Pieris rapae). This wide ranging, highly dispersive and invasive pest periodically encounters metal pollution by consuming plants in urban and agricultural settings. In contrast to expected costs of tolerance, we found that cabbage white families with greater zinc tolerance also produced more eggs and had higher reproductive effort under nonpolluted conditions. These results contribute to a more general hypothesis of why costs of pollution tolerance vary across studies: patchy selection with pollutants should erode costs and may favour genotypes that perform well under both polluted and nonpolluted conditions. This might partly explain why widely distributed invasive species are able to thrive in diverse, polluted and nonpolluted habitats.

Background Community engagement (CE) interventions include a range of approaches to involve communities in the improvement of their health and wellbeing. Working with communities defined by location or some other shared interest, these interventions may be important in assisting equity and reach of communicable disease control (CDC) in low and lower-middle income countries (LLMIC). We conducted an umbrella review to identify approaches to CE in communicable disease control, effectiveness of these approaches, mechanisms and factors influencing success. Methods We included systematic reviews that: i) focussed on CE interventions; ii) involved adult community members; iii) included outcomes relevant to communicable diseases in LLMIC; iv) were written in English. Quantitative results were extracted and synthesised narratively. A qualitative synthesis process enabled identification of mechanisms of effect and influencing factors. We followed guidance from the Joanna Briggs Institute, assessed quality with the DARE tool and reported according to standard systematic review methodology. Results Thirteen systematic reviews of medium-to-high quality were identified between June and July 2017. Reviews covered the following outcomes: HIV and STIs (6); malaria (2); TB (1); child and maternal health (3) and mixed (1). Approaches included: CE through peer education and community health workers, community empowerment interventions and more general community participation or mobilisation. Techniques included sensitisation with the community and involvement in the identification of resources, intervention development and delivery. Evidence of effectiveness of CE on health outcomes was mixed and quality of primary studies variable. We found: i) significantly reduced neonatal mortality following women’s participatory learning and action groups; ii) significant reductions in HIV and other STIs with empowerment and mobilisation interventions with marginalised groups; iii) significant reductions in malaria incidence or prevalence in a small number of primary studies; iv) significant reductions in infant diarrhoea following community health worker interventions. Mechanisms of impact commonly occurred through social and behavioural processes, particularly: changing social norms, increasing social cohesion and social capacity. Factors influencing effectiveness of CE interventions included extent of population coverage, shared leadership and community control over outcomes. Conclusion Community engagement interventions may be effective in supporting CDC in LLMIC. Careful design of CE interventions appropriate to context, disease and community is vital.

Organisms encounter a wide range of toxic compounds in their environments, from chemicals that serve anticonsumption or anticompetition functions to pollutants and pesticides. Although we understand many detoxification mechanisms that allow organisms to consume toxins typical of their diet, we know little about why organisms vary in their ability to tolerate entirely novel toxins. We tested whether variation in generalized stress responses, such as antioxidant pathways, may underlie variation in reactions to novel toxins and, if so, their associated costs. We used an artificial diet to present cabbage white butterfly caterpillars (

Zinc is a widespread pollutant released from industrial combustion, automobile residue, and mining. Zinc accumulates in soils and mobilises into plant tissue where it may be consumed to potentially toxic levels by leaf feeding insects, including developing pollinators. While zinc tolerance thresholds have been previously assessed in insect pollinators, most observations are limited to model organisms and pest species. We lack understanding of zinc tolerance in insects of conservation concern. We assess dietary zinc tolerance of developing caterpillars from wild populations of the monarch butterfly (Danaus plexippus), a species of conservation concern, whose caterpillars are commonly exposed to elevated dietary zinc exposure in milkweed plants along roadsides. We contrast monarch zinc tolerance with that of cabbage white butterfly caterpillars (Pieris rapae), a non‐native pest species. Tolerance was assessed by rearing caterpillars on artificial diets containing varying levels of zinc. Zinc reduced monarch survival at levels as low as 344 mg kg⁻¹ but positively impacted cabbage white survival at 227 and 738 mg kg⁻¹. Cabbage whites also displayed prolonged development time, smaller adult body size, and slower growth rate, consistent with the possibility that zinc tolerance had fitness costs. Our results support previous observations that heavy metal tolerance varies between species and highlight the importance of broadening our understanding of tolerance to insect species of conservation concern before drawing general conclusions about insect susceptibility to heavy metal pollution. Nonetheless, our results suggest that zinc pollution alone is unlikely a risk in developing roadside habitat for monarch butterflies.

Significance Beyond sugars, many types of nectar solutes play important ecological roles; however, the molecular basis for the diversity of nectar composition across species is less explored. One rare trait among flowering plants is the production of colored nectar, which may function to attract and guide prospective pollinators. Our findings indicate convergent evolution of a red-colored nectar has occurred across two distantly related plant species. Behavioral data show that the red pigment attracts diurnal geckos, the likely pollinator of one of these plants. These findings join a growing list of examples of distinct biochemical and molecular mechanisms underlying evolutionary convergence and provide a fascinating system for testing how interactions across species drive the evolution of novel pigments in an understudied context.

(1) Generating a range of biological analogies is a key part of the bio-inspired design process. In this research, we drew on the creativity literature to test methods for increasing the diversity of these ideas. We considered the role of the problem type, the role of individual expertise (versus learning from others), and the effect of two interventions designed to increase creativity—going outside and exploring different evolutionary and ecological “idea spaces” using online tools. (2) We tested these ideas with problem-based brainstorming assignments from a 180-person online course in animal behavior. (3) Student brainstorming was generally drawn to mammals, and the breadth of ideas was affected more by the assigned problem than by practice over time. Individual biological expertise had a small but significant effect on the taxonomic breadth of ideas, but interactions with team members did not. When students were directed to consider other ecosystems and branches of the tree of life, they increased the taxonomic diversity of biological models. In contrast, going outside resulted in a significant decrease in the diversity of ideas. (4) We offer a range of recommendations to increase the breadth of biological models generated in the bio-inspired design process.

Proverbs. An Eclectic Edition with Introduction and Textual Commentary. By Michael V. Fox. The Hebrew Bible: A Critical Edition, vol. 1. Atlanta: SBL Press, 2015. Pp. xxii + 431, 42*. $69.95.

Symmetric, progressive, necrotizing lesions in the brainstem are a defining feature of Leigh syndrome (LS). A mechanistic understanding of the pathogenesis of these lesions has been elusive. Here, we report that leukocyte proliferation is causally involved in the pathogenesis of LS. Depleting leukocytes with a colony-stimulating factor 1 receptor inhibitor disrupted disease progression, including suppression of CNS lesion formation and a substantial extension of survival. Leukocyte depletion rescued diverse symptoms, including seizures, respiratory center function, hyperlactemia, and neurologic sequelae. These data reveal a mechanistic explanation for the beneficial effects of mTOR inhibition. More importantly, these findings dramatically alter our understanding of the pathogenesis of LS, demonstrating that immune involvement is causal in disease. This work has important implications for the mechanisms of mitochondrial disease and may lead to novel therapeutic strategies.

Biologists seek to understand why organisms vary in their abilities to tolerate anthropogenic contaminants, such as heavy metals. However, few studies have considered how tolerance may be affected by condition-moderating factors such as dietary resource availability. For instance, the availability of crucial limiting macronutrients, such as nitrogen and phosphorous, can vary across space and time either naturally or due to anthropogenic nutrient inputs (e.g., agricultural fertilizers or vehicle emissions). Organisms developing in more macronutrient-rich environments should be of higher overall condition, displaying a greater ability to tolerate metal contaminants. In monarch butterflies (Danaus plexippus), we factorially manipulated dietary macronutrient availability and exposure to zinc, a common metal contaminant in urban habitats that can be toxic but also has nutritional properties. We tested whether (1) the ability to survive zinc exposure depends on dietary macronutrient availability and (2) whether individuals exposed to elevated zinc levels display higher expression of antioxidant genes, given the roles of antioxidants in combatting metal-induced oxidative stress. Exposure to elevated zinc reduced survival only for monarchs developing on a low-macronutrient diet. However, for monarchs developing on a high-macronutrient diet, elevated zinc exposure tended to increase survival. In addition, monarchs exposed to elevated zinc displayed higher expression of antioxidant genes when developing on the low-macronutrient diet but lower expression when developing on the high-macronutrient diet. Altogether, our study shows that organismal survival and oxidative stress responses to anthropogenic zinc contamination depend on the availability of macronutrient resources in the developmental environment. In addition, our results suggest the hypothesis that whether zinc acts as a toxicant or a nutrient may depend on macronutrient supply. Environ Toxicol Chem 2022;41:1286-1296. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Humans are increasing micronutrients in roadside habitats to levels that are potentially stressful for insect pollinators. We show that combined exposure to levels of sodium and zinc characteristic of high-traffic roadsides do not impact survival of developing monarch butterflies (Danaus plexippus), but sodium increases relative eye size and prolongs development., Human activities are increasing the environmental availability of micronutrients, including sodium and some essential metals. Micronutrients are often limiting in animal diets but may have negative effects when consumed in excess. Though prior research has documented how elevated exposure to individual micronutrients can impact organismal development and fitness, we know less about combined effects of multiple micronutrients. In the wild, monarch butterfly larvae (Danaus plexippus) commonly consume plants in roadside habitats that contain elevated levels of sodium (from road salt) and zinc (from vehicle wear-and-tear). We reared monarch caterpillars to adulthood to test individual and combined effects of dietary sodium and zinc on components of fitness, sodium-linked phenotypes (proxies for neural and flight muscle development) and concentrations of sodium and zinc in adult butterflies. Monarch survival was not impacted by elevated sodium or zinc individually or in combination. Yet, monarchs feeding on sodium-treated milkweed developed relatively larger eyes, consistent with a positive effect of sodium on neural development. Measurements of element concentrations in butterfly and plant tissue indicated that monarchs had higher zinc levels than those present in zinc-treated milkweed but lower sodium levels than those present in sodium-treated milkweed. Monarchs developing on sodium-treated milkweed also had prolonged development time, which might be a cost associated with developing extra neural tissue or investing in mechanisms to excrete excess dietary sodium during the larval stage. Our results indicate that sodium, more than zinc, is likely influencing phenotypic development and performance of insect pollinators in roadside habitats. Yet, in contrast to previous work, our experiment suggests that the highest levels of sodium found along roads are not always harmful for developing monarchs. Future work could consider how potentially stressful effects of micronutrients could be mitigated by increased macronutrient availability or how developmental factors such as migratory status might increase micronutrient requirements.

Thirty-nine patients with pathologically proven breast cancer underwent 20-min dynamic PET/computed tomography imaging following the administration ofA reversible one-tissue compartment model was shown to best describe tracer uptake in breast cancer. No significant differences were seen in kinetic or static parameters for different tumour receptor subtypes or grades. Kinetic and static parameters showed a good correlation.NCT03036943.

Humans have drastically increased the availability of many once-limited nutrients, resulting in potential attraction of animals to now toxic, novel nutritional conditions. For instance, herbivores are attracted to sodium in many terrestrial ecosystems because sodium occurs in much lower concentrations in plants than in animals. However, sodium availability has increased due to crop irrigation or distribution of de-icing salts along roads. While moderate increases in once-limited sodium may be beneficial, large increases are potentially toxic. Here, we investigate whether increased sodium along roadsides is functioning as an ecological trap, drawing butterflies to oviposit and forage on plants with toxic levels of sodium. As in many other animals, butterflies exhibit sodium-specific foraging behaviour – males will ‘puddle’ for minerals on mud, dung or carrion; yet sodium-seeking behaviours at other life stages remain unexplored. We present data from a series of field- and laboratory-based sodium preference trials using both caterpillars and ovipositing adult females. Female monarch and cabbage white butterflies did not show any preference for laying eggs on sodium-enriched plants, either at moderate levels that are likely to be physiologically beneficial, or at potentially toxic levels typical of high-traffic roads. Monarch caterpillars somewhat avoided the plants highest in sodium, but this behaviour is unlikely to compensate for the failure of ovipositing females to avoid toxic high-sodium plants. These results suggest that while butterflies frequently use sodium-enriched roadside habitats, they are unlikely to be seeking out or avoiding these areas due to elevated sodium.

Background The arteriovenous fistula (AVF) is central to haemodialysis treatment, but up to half of surgically created AVF fail to mature. Chronic kidney disease often leads to mineral metabolism disturbances that may interfere with AVF maturation through adverse vascular effects. This study tested associations between mineral metabolism markers and vein histology at AVF creation and unassisted and overall clinical AVF maturation. Methods Concentrations of fibroblast growth factor 23, parathyroid hormone, calcium, phosphate, and vitamin D metabolites: 1,25(OH)2D, 24,25(OH)2D, 25(OH)D, and bioavailable 25(OH)D were measured in pre-operative serum samples from 562 of 602 participants in the Haemodialysis Fistula Maturation Study, a multicentre, prospective cohort study of patients undergoing surgical creation of an autologous upper extremity AVF. Unassisted and overall AVF maturation were ascertained for 540 and 527 participants, respectively, within nine months of surgery or four weeks of dialysis initiation. Study personnel obtained vein segments adjacent to the portion of the vein used for anastomosis, which were processed, embedded, and stained for measurement of neointimal hyperplasia, calcification, and collagen deposition in the medial wall. Results Participants in this substudy were 71% male, 43% black, and had a mean age of 55 years. Failure to achieve AVF maturation without assistance occurred in 288 (53%) participants for whom this outcome was determined. In demographic and further adjusted models, mineral metabolism markers were not significantly associated with vein histology characteristics, unassisted AVF maturation failure, or overall maturation failure, other than a biologically unexplained association of higher 24,25(OH)2D with overall failure. This exception aside, associations were non-significant for continuous and categorical analyses and relevant subgroups. Conclusions Serum concentrations of measured mineral metabolites were not substantially associated with major histological characteristics of veins in patients undergoing AVF creation surgery, or with AVF maturation failure, suggesting that efforts to improve AVF maturation rates should increase attention to other processes such as vein mechanics, anatomy, and cellular metabolism among end stage renal disease patients.

Biologists have long been interested in the factors that maintain variation in learning and plasticity within and between species, especially given the role of such flexibility in coping with novel and changing environments. A large body of theoretical and empirical work has established the role of environmental variation in selecting for learning and plasticity, suggesting that simple measures of such variation could serve as proxies for organismal flexibility. However, a wide range of behavioural and physiological traits can shape how organisms experience environmental variation, and thus how plasticity is shaped by selection. Given that these traits themselves can evolve, this sets up the potential for complex feedbacks in the evolution of learning and plasticity. We begin this review by first detailing the wide variety of behavioural traits that shape environmental variation, ranging from exploration and dispersal to sensory biases and habitat choice. We then review relevant theory that suggests how such behavioural traits can modify selection on learning and plasticity, often favouring the evolution of specialization in heterogeneous environments by reducing the variation that organisms experience. When models allow behavioural traits to jointly evolve with plasticity, model outcomes differ and complex evolutionary feedbacks may emerge. We suggest that further theoretical insights could be gained by incorporating more nuances of development and behaviour, such as variation in the developmental window of environmental sensitivity of traits or differences in exploratory periods prior to breeding. Finally, this review discusses implications of this perspective for understanding the maintenance of genetic variation in learning, differences in colonization and survival in novel environments and making predictions about how species will cope with environmental change.

This chapter reviews the ecological conditions that favor the evolution of plasticity, and the costs and limits that constrain the evolution of plasticity. Variable environments tend to select for plasticity, especially when there are reliable cues of future environmental conditions. However, organismal biology also shapes how individuals experience environmental variation and the reliability of cues, creating opportunities for feedbacks in the evolution of plasticity. Constant environments can also select for plasticity when these environments are novel, or incredibly divergent from ancestral conditions, but such selection should be transient, especially if there are associated costs of plasticity. Empirical studies have documented costs associated with both the induction of plastic traits and the ability to be plastic. Such fitness tradeoffs stem from costs of the developmental process of plasticity and from limits to the range of plasticity. While costs of plasticity are found more often than expected by chance, they are often smaller and less frequent than generally assumed, for reasons we outline here. Finally, this chapter discusses exciting areas for future research in the ecology and evolution of plasticity, including expanding our theoretical understanding with more developmentally realistic models and exploring eco-evolutionary feedbacks.