Toxicity and taste:unequal chemical defences in a mimicry ring

Mimicry of warning signals is common, and can be mutualistic when mimetic species harbour equal levels of defence (Müllerian), or parasitic when mimics are undefended but still gain protection from their resemblance to the model (Batesian). However, whether chemically defended mimics should be similar in terms of toxicity (i.e. causing damage to the consumer) and/or unpalatability (i.e. distasteful to consumer) is unclear and in many studies remains undifferentiated. In this study, we investigated the evolution of visual signals and chemical defences in a putative mimicry ring of nudibranch molluscs. First, we demonstrated that the appearance of a group of red spotted nudibranchs molluscs was similar from the perspective of potential fish predators using visual modelling and pattern analysis. Second, using phylogenetic reconstruction, we demonstrated that this colour pattern has evolved multiple times in distantly related individuals. Third, we showed that these nudibranchs contained different chemical profiles used for defensive purposes. Finally, we demonstrated that although levels of distastefulness towards Palaemon shrimp remained relatively constant between species, toxicity levels towards brine shrimp varied significantly. We highlight the need to disentangle toxicity and taste when considering chemical defences in aposematic and mimetic species, and discuss the implications for aposematic and mimicry signal evolution

A holistic framework of corporate website favourability

This paper extends the current knowledge of corporate website favourability (CWF) by developing a comprehensive conceptual model of its influence on corporate image, corporate reputation, loyalty and identification. The paper reviews previous studies on corporate websites from the perspectives of marketing, management, corporate identity and corporate visual identity in order to inform our understanding of the antecedents and consequences of CWF. The propositions and the conceptual framework present an approach by which a corporation can design and manage a favourable corporate website. A number of important contributions are offered: First, the paper adds to the understanding of CWF; second, it discusses the antecedents of CWF by drawing upon the existing literature; third, it is beneficial for practitioners in shaping CWF strategies, and fourth, it offers possible consequences of CWF and provides a framework for future testing

Система организации процесса проектного финансирования

У статті систематизовано процес організації проектного фінансування через сукупність принципів та етапів організації процесу фінансування проектів, суб’єктів та об’єктів, методів та джерел формування капіталу, методології оцінки ефективності проектів, інструментів управління проектними ризиками, нормативно-правового та інформаційного забезпечення взаємовідносин між учасниками такого фінансування. Крім того, досліджено внутрішнє та зовнішнє середовище проектного фінансування, розкрито зміст системи проектного фінансування, виокремлено етапи процесу організації проектного фінансування та представлено їх коротку характеристику. Використання таких методів наукового дослідження, як систематизація та узагальнення дало можливість уточнити складові системи організації процесу проектного фінансування та виділити принципи організації проектного фінансування, а методів аналізу та синтезу — конкретизувати етапи організації процесу проектного фінансування. Подальші дослідження спрямовуватимуться на поглиблене вивчення та деталізацію окремих компонентів етапів організації процесу проектного фінансування з метою визначення можливостей їх застосування в практичній діяльності суб’єктів проектного фінансування та використання при побудові алгоритму реалізації конкретного проекту за схемою проектного фінансування.This article systematizes an organization process for project financing through a set of principles and milestones of projects funding, subjects and objects, methods and sources of raising capital, methodology for project effectiveness assessing, tools for project risk management, legal and information support for the participants of project funding. Moreover, the article studies the internal and external environment for project financing, reveals the content of project financing system, identifies milestones of organization process for project financing, and presents their brief description. The use of such methods of scientific research as systematization and generalization makes it possible to refine the components of organization system for project financing and identify project financing principles, as well as specify the milestones of project financing process through the methods of analysis and synthesis. Further research supposes in-depth study and specification of individual components of project financing milestones to ensure their practical application and developing an algorithm for a specific project implementation in terms of project financing pattern.В статье систематизирован процесс организации проектного финансирования посредством совокупности принципов и этапов организации процесса финансирования проектов, субъектов и объектов, методов и источников формирования капитала, методологии оценки эффективности проектов, инструментов управления проектными рисками, нормативно-правового и информационного обеспечения отношений между участниками такого финансирования. Кроме этого, исследованы внутренняя и внешняя среда проектного финансирования, раскрыто содержание системы проектного финансирования, выделены этапы процесса организации проектного финансирования и представлена их короткая характеристика. Использование таких методов научного исследования как систематизация и обобщение дало возможность уточнить составляющие системы организации процесса проектного финансирования и выделить принципы организации проектного финансирования, а методов анализа и синтеза — конкретизировать этапы организации процесса проектного финансирования. Дальнейшие исследования будут направлены на углубленное изучение и детализацию отдельных составляющих этапов организации процесса проектного финансирования с целью определения возможностей их использования в практической деятельности субъектов проектного финансирования и использования при построении алгоритма реализации конкретного проекта в пределах схемы проектного финансирования

Toxicity and taste: unequal chemical defences in a mimicry ring.

Mimicry of warning signals is common, and can be mutualistic when mimetic species harbour equal levels of defence (Müllerian), or parasitic when mimics are undefended but still gain protection from their resemblance to the model (Batesian). However, whether chemically defended mimics should be similar in terms of toxicity (i.e. causing damage to the consumer) and/or unpalatability (i.e. distasteful to consumer) is unclear and in many studies remains undifferentiated. In this study, we investigated the evolution of visual signals and chemical defences in a putative mimicry ring of nudibranch molluscs. First, we demonstrated that the appearance of a group of red spotted nudibranchs molluscs was similar from the perspective of potential fish predators using visual modelling and pattern analysis. Second, using phylogenetic reconstruction, we demonstrated that this colour pattern has evolved multiple times in distantly related individuals. Third, we showed that these nudibranchs contained different chemical profiles used for defensive purposes. Finally, we demonstrated that although levels of distastefulness towards Palaemon shrimp remained relatively constant between species, toxicity levels towards brine shrimp varied significantly. We highlight the need to disentangle toxicity and taste when considering chemical defences in aposematic and mimetic species, and discuss the implications for aposematic and mimicry signal evolution

Data from: Stabilizing selection on individual pattern elements of aposematic signals

Warning signal variation is ubiquitous but paradoxical: low variability should aid recognition and learning by predators. However, spatial variability in the direction and strength of selection for individual elements of the warning signal may allow phenotypic variation for some components, but not others. Variation in selection may occur if predators only learn particular colour pattern components rather than the entire signal. Here, we used a nudibranch mollusc, Goniobranchus splendidus, which exhibits a conspicuous red spot/white body/yellow rim colour pattern, to test this hypothesis. We first demonstrated that secondary metabolites stored within the nudibranch were unpalatable to a marine organism. Using pattern analysis, we demonstrated that the yellow rim remained invariable within and between populations; however, red spots varied significantly in both colour and pattern. In behavioural experiments, a potential fish predator, Rhinecanthus aculeatus, used the presence of the yellow rims to recognize and avoid warning signals. Yellow rims remained stable in the presence of high genetic divergence among populations. We therefore suggest that how predators learn warning signals may cause stabilizing selection on individual colour pattern elements, and will thus have important implications on the evolution of warning signals.,Anti-feedant assay dataG.splendidus_PS.pzfxBehavioural experiments datarscriptanddataforbordersmanuscript.zipColour contrast dataColour.zipPattern fraction of transitions dataPattern.zipSequence datasequences.zip

Supplementary Figures and Tables from Toxicity and taste: unequal chemical defences in a mimicry ring

<b>Figure S1:</b> Representative photographs of the non-red spot species: A) <i>Ceratosoma amoenum</i>, B) <i>Chromodoris kuiteri</i>, C) <i>Chromodoris lochi</i>, D) <i>Chromodoris elisabethina</i>, E) <i>Doriprismatica atromarginata</i>, F) <i>Goniobranchus decorus</i>, G) <i>Goniobranchus geometricus</i>, H) <i>Hypselodoris jacksoni</i>, I) <i>Hypselodoris obscura</i>, J) <i>Hypselodoris tryoni</i>, K) <i>Hypselodoris whitei</i>, L) <i>Risbecia godeffroyana</i>; <b>Figure S2: a) Toxicity assay</b>: LD₅₀ values based on mortality of Brine shrimp, <i>Artemia</i> sp. <b>b) Anti-feedant assay.</b> ED₅₀ values based on rejection of pellets by Palaemon shrimp, <i>Palaemon serenus</i> Y-axis indicates absolute concentrations rather than proportion of natural concentration (Figure 4). Cross indicates no response (nr) observed when tested at the highest concentration. Open circle indicates that a response was observed but not significant enough to calculate an ED₅₀ value.; <b>Figure S3:</b> ED₅₀ and LD₅₀ values are plotted for 6 species. The graph is separated into four zones, which coincide with relative toxicity and/or palatability of the species within.; <b>Figure S4:</b> Dose response curves for a) brine shrimp assays and b) palaemon shrimp assays.; <b>Table S1:</b> Specimen collection information.; <b>Table S2:</b> Species and data used to construct the phylogeny. Genbank accession numbers are listed for COI and 16S genes along with specimen voucher numbers. Outgroups are shown in bold. * indicates that for these species new sequences were generated as part of this study.; <b>Table S3:</b> Colour pattern characteristics for each species used in NMDS plots. Zero values are generated for hue if the distance from the achromatic point was very low and hence the angle and direction from the achromatic point unreliable. When the pattern was complex, the dominant pattern used to calculate the measurements are named below the values.; <b>Table S4:</b> Chemical compounds found in each species of nudibranch