Versatile aggressive mimicry of cicadas by an Australian predatory katydid

Deceptive Seduction by Femme Fatale Fireflies and Its Avoidance by Males of a Synchronous Firefly Species (Coleoptera: Lampyridae)

Photuris female fireflies attract males of different firefly species by responding to their flashing signals; then, they try to capture and feed on them. This aggressive mimicry is considered a major selective pressure on the communication systems of the fireflies of the American continent. The intensity of this selective pressure is a function of its efficiency in prey capture. In this study, the rates of attraction and capture of males of the synchronous firefly Photinus palaciosi by the predatory females of Photuris lugubris are reported. Although the females attract numerous males, their hunting success is low. This result is consistent with the few previous measurements published. In agreement with the predicted coevolutionary race between predator and prey, behaviors consistent with predation avoidance in P. palaciosi and increasing prey encounters and prey deception by P. lugubris were observed.

Sexual selection and 'species recognition' revisited: serial processing and order-of-operations in mate choice

Following the modern synthesis, mating signals were thought of principally as species recognition traits, a view later challenged by a burgeoning interest in sexual selection-specifically mate choice. In the 1990s, these different signal functions were proposed to represent a single process driven by the shape of female preference functions across both intra- and interspecific signal space. However, the properties of reliable 'recognition' signals (stereotyped; low intraspecific variation) and informative 'quality' signals (condition dependent; high intraspecific variation) seem at odds, perhaps favouring different signal components for different functions. Surprisingly, the idea that different components of mating signals are evaluated in series, first to recognize generally compatible mates and then to select for quality, has never been explicitly tested. Here I evaluate patterns of (i) intraspecific signal variation, (ii) female preference function shape and (iii) phylogenetic signal for male cricket call components known to be processed in series. The results show that signal components processed first tend to have low variation, closed preference functions and low phylogenetic signal, whereas signal components processed later show the opposite, suggesting that mating signal evaluation follows an 'order-of-operations'. Applicability of this finding to diverse groups of organisms and sensory modalities is discussed.

Symptomic Mimicry Between SARS-CoV-2 and the Common Cold Complex

The recent changes in COVID-19 symptoms suggest convergent evolution of respiratory diseases. This process is analogous to the emergence of animal mimetic complexes and complements previously identified types of mimicry. A novel pathogen might go unnoticed or insufficiently counteracted if it resembles a disease that the host already faced on multiple occasions, which creates a selective pressure towards a typical symptomic phonotype. In short, the reason why so many unrelated pathogens cause similar symptoms may correspond to the reasons that drove the evolution of the 'warning' wasp-like colouration in various insect species.

Advances in the Evolution and Ecology of 13- and 17-Year Periodical Cicadas

Apart from model organisms, 13- and 17-year periodical cicadas (Hemiptera: Cicadidae: Magicicada) are among the most studied insects in evolution and ecology. They are attractive subjects because they predictably emerge in large numbers; have a complex biogeography shaped by both spatial and temporal isolation; and include three largely sympatric, parallel species groups that are, in a sense, evolutionary replicates. Magicicada are also relatively easy to capture and manipulate, and their spectacular, synchronized mass emergences facilitate outreach and citizen science opportunities. Since the last major review, studies of Magicicada have revealed insights into reproductive character displacement and the nature of species boundaries, provided additional examples of allochronic speciation, found evidence for repeated and parallel (but noncontemporaneous) evolution of 13- and 17-year life cycles, quantified the amount and direction of gene flow through time, revealed phylogeographic patterning resulting from paleoclimate change, examined the timing of juvenile development, and created hypotheses for the evolution of life-cycle control and the future effects of climate changeon Magicicada life cycles. New ecological studies have supported and questioned the role of prime numbers in Magicicada ecology and evolution, found bidirectional shifts in population size over generations, quantified the contribution of Magicicada to nutrient flow in forest ecosystems, and examined behavioral and biochemical interactions between Magicicada and their fungal parasites and bacterial endosymbionts.

Thirteen new species of Chilecicada Sanborn, 2014 (Hemiptera: Auchenorrhyncha: Cicadidae: Tibicininae) expand the highly endemic cicada fauna of Chile

The genus Chilecicada Sanborn, 2014 is shown to be a complex of closely related species rather than a monospecific genus. Chilecicada citatatemporaria Sanborn & Cole n. sp., C. culenesensis Sanborn & Cole n. sp., C. curacaviensis Sanborn & Cole n. sp., C. impartemporaria Sanborn & Cole n. sp., C. magna Sanborn & Cole n. sp., C. mapuchensis Sanborn n. sp., C. oraria Sanborn & Cole n. sp., C. parrajaraorum Sanborn n. sp., C. partemporaria Sanborn & Cole n. sp., C. pehuenchesensis Sanborn & Cole n. sp., C. trifascia Sanborn n. sp., C. trifasciunca Sanborn & Cole n. sp., and C. viridicitata Sanborn & Cole n. sp. are described as new. Chilecicada occidentis Walker, 1850 is re-described to facilitate separation of the new species from the only previously known species. Song and cytochrome oxidase I analysis available for most species support the separation of the new taxa from the type species of the genus. Known species distributions and a key to the species of the genus are also provided. The new species increases the known cicada diversity 61.9% to 34 species, 91.2% of which are endemic to Chile.

Phylogeography of the endemic red-tailed cicadas of New Zealand (Hemiptera: Cicadidae: Rhodopsalta), and molecular, morphological and bioacoustical confirmation of the existence of Hudson’s Rhodopsalta microdora

Why do some genera radiate, whereas others do not? The genetic structure of present-day populations can provide clues for developing hypotheses. In New Zealand, three Cicadidae genera are depauperate [Amphipsalta (three species), Notopsalta (one species) and Rhodopsalta (three species)], whereas two have speciated extensively [Kikihia (~30 species/subspecies) and Maoricicada (~20 species/subspecies). Here, we examine the evolution of Rhodopsalta, the last New Zealand genus to be studied phylogenetically and phylogeographically. We use Bayesian and maximum-likelihood analyses of mitochondrial cox1 and nuclear EF1α gene sequences. Concatenated and single-gene phylogenies for 70 specimens (58 localities) support its monophyly and three described species: Rhodopsalta cruentata, Rhodopsalta leptomera and Rhodopsalta microdora, the last taxon previously regarded as uncertain. We provide distribution maps, biological notes and the first descriptions of diagnostic songs. We show that both R. cruentata and R. microdora exhibit northern and southern genetic subclades. Subclades of the dry-adapted R. microdora clade show geographical structure, whereas those of the mesic R. cruentata and sand-dune specialist R. leptomera have few discernible patterns. Genetic, bioacoustical and detailed distributional evidence for R. microdora add to the known biodiversity of New Zealand. We designate a lectotype for Tettigonia cruentata  Fabricius, 1775, the type species of Rhodopsalta.

Females prefer males producing a high-rate song with shorter timbal–stridulatory sound intervals in a cicada species

Uncovering mate choice and factors that lead to the choice are very important to understanding sexual selection in evolutionary change. Cicadas are known for their loud sounds produced by males using the timbals. However, males in certain cicada species emit 2 kinds of sounds using respectively timbals and stridulatory organs, and females may produce their own sounds to respond to males. What has never been considered is the mate choice in such cicada species. Here, we investigate the sexual selection and potential impact of predation pressure on mate choice in the cicada Subpsaltria yangi Chen. It possesses stridulatory sound-producing organs in both sexes in addition to the timbals in males. Results show that males producing calling songs with shorter timbal–stridulatory sound intervals and a higher call rate achieved greater mating success. No morphological traits were found to be correlated with mating success in both sexes, suggesting neither males nor females display mate preference for the opposite sex based on morphological traits. Males do not discriminate among responding females during mate searching, which may be due to the high energy costs associated with their unusual mate-seeking activity and the male-biased predation pressure. Females generally mate once but a minority of them re-mated after oviposition which, combined with the desirable acoustic traits of males, suggest females may maximize their reproductive success by choosing a high-quality male in the first place. This study contributes to our understanding mechanisms of sexual selection in cicadas and other insects suffering selective pressure from predators.

The false cleanerfish relies on aggressive mimicry to bite fish fins when benthic foods are scarce in their local habitat

The false cleanerfish, Aspidontus taeniatus (Blenniidae), is known for its morphological resemblance to the bluestreak cleaner wrasse Labroides dimidiatus (Labridae). It has been suggested that A. taeniatus, which acts as a mimic, can easily bite the fins of other fishes that are deceived into requesting cleaning from it or allowing it to approach them. In fact, A. taeniatus frequently utilises benthic food items, such as damselfish eggs, the Christmas tree worm Spirobranchus giganteus, and the boring clam Tridacna crocea. Although geographical variation in the reliance on aggressive mimicry (fin biting) has been reported, the factors have not been determined. We hypothesised that one of the factors is the abundance of benthic food items. To examine our hypothesis, we compared the feeding behaviour of A. taeniatus at two locations showing contrasting abundances of benthic food items in Okinawa, southern Japan. The frequency of fin biting by the small A. taeniatus in Ishigaki Island, where S. giganteus and T. crocea were very rare, was significantly higher than that in Sesoko Island, where the two food items were abundant. We conclude that the importance of aggressive mimicry in A. taeniatus varies depending on local food conditions.

When honesty and cheating pay off: the evolution of honest and dishonest equilibria in a conventional signalling game

Background

The reliability of signals is a key issue in the study of animal communication. Both empirical work and theoretical models show that communication need not be entirely honest, and thus signals can be deceitful. Aggressive communication appears to be a prime candidate for such deceitful communication, because bluffing has been described in several species. Bluffing in these situations are supposed to be maintained by frequency dependent selection where the fitness of a given type depends on the frequencies of the other types in the population. Previous efforts to model such a scenario through individual based simulations have yielded conflicting results. Studies have either found a rich set of polymorphic strategies including the traditional cheating scenario or found none. Thus, the modelling assumptions responsible for these diverging conclusions remain unclear.

Results

In this study, I investigate the effects of four modelling assumptions: the role of an extended strategy set, the initial population composition (seeding), the differences in pay-offs and finally different parameter spaces. I investigate the effects of these factors on the evolvability of both honest and mixed cheating strategies. I show that both honest and cheating equilibria readily evolve and that the investigated parameter range and the seeding of the starting populations have the greatest influence on the outcome.

Conclusions

Both honest signalling and polymorphic cheating equilibria are more likely to evolve from a narrow strategy set than from a random mixture of strategies. A large potential strategy set is not a setback for the evolution of communication -honest or cheating- as long as the initial population is seeded with only a few strategies. In addition, different sections of the parameter space show consistently different behaviour. Thus, frequency dependent selection has the potential to explain various empirical observations that show consistent differences in aggressive behaviour.

Electronic supplementary material

The online version of this article (10.1186/s12862-017-1112-y) contains supplementary material, which is available to authorized users.

Sexual pair-formation in a cicada mediated by acoustic behaviour of females and positive phonotaxis of males

The functions of female song found in a few cicadas have rarely been studied. In the cicada Subpsaltria yangi we investigated the acoustic behaviour and signal structure of songs produced by females, the phonotaxis of males, and mate choice, as well as the selective pressure imposed on this species by predators. Pair-formation in S. yangi occurs when males signal, females respond, then males move to signaling females, which is opposite to that in most other cicadas where females move to calling males. Females only mate once and are sexually unreceptive after copulation. Most males mate once, but ~25% mate multiply. Females display little direct evidence of mate preference or choice of males, and all mate encounters led to a successful mating. Only males are attacked by a robber fly, Philonicus albiceps, while flying to females. This imposes strong selection on males – only males who can evade predators mate. Males are also attracted to human simulations of female calls. This behaviour exposes the mating system to impacts from anthropogenic noise systems which could disrupt mating activity of this species. Our results improve the understanding of mate choice/competition in cicadas, and are valuable for future studies of the evolution of sound communication in the Cicadoidea.

An exceptionally preserved 110 million years old praying mantis provides new insights into the predatory behaviour of early mantodeans

Mantodeans or praying mantises are flying insects and well known for their raptorial behaviour, mainly performed by their first pair of thoracic appendages. We describe here a new, exceptionally preserved specimen of the early mantodean Santanmantis axelrodi Grimaldi, 2003 from the famous 110 million years old Crato Formation, Brazil. The incomplete specimen preserves important morphological details, which were not known in this specific form before for this species or any other representative of Mantodea. Unlike in modern representatives or other fossil forms of Mantodea not only the first pair of thoracic appendages shows adaptations for predation. The femora of the second pair of thoracic appendages bear numerous strong, erect spines which appear to have a sharp tip, with this strongly resembling the spines of the first pair of thoracic appendages. This indicates that individuals of S. axelrodi likely used at least two pairs of thoracic appendages to catch prey. This demonstrates that the prey-catching behaviour was more diverse in early forms of praying mantises than anticipated.

The evolutionary ecology of deception

Through dishonest signals or actions, individuals often misinform others to their own benefit. We review recent literature to explore the evolutionary and ecological conditions for deception to be more likely to evolve and be maintained. We identify four conditions: (1) high misinformation potential through perceptual constraints of perceiver; (2) costs and benefits of responding to deception; (3) asymmetric power relationships between individuals and (4) exploitation of common goods. We discuss behavioural and physiological mechanisms that form a deception continuum from secrecy to overt signals. Deceptive tactics usually succeed by being rare and are often evolving under co-evolutionary arms races, sometimes leading to the evolution of polymorphism. The degree of deception can also vary depending on the environmental conditions. Finally, we suggest a conceptual framework for studying deception and highlight important questions for future studies.

Computational themes of peripheral processing in the auditory pathway of insects

Hearing in insects serves to gain information in the context of mate finding, predator avoidance or host localization. For these goals, the auditory pathways of insects represent the computational substrate for object recognition and localization. Before these higher level computations can be executed in more central parts of the nervous system, the signals need to be preprocessed in the auditory periphery. Here, we review peripheral preprocessing along four computational themes rather than discussing specific physiological mechanisms: (1) control of sensitivity by adaptation, (2) recoding of amplitude modulations of an acoustic signal into a labeled-line code (3) frequency processing and (4) conditioning for binaural processing. Along these lines, we review evidence for canonical computations carried out in the peripheral auditory pathway and show that despite the vast diversity of insect hearing, signal processing is governed by common computational motifs and principles.

A female-emitted pheromone component is associated with reduced male courtship in the parasitoid wasp Spalangia endius

During courtship interactions, the courted individual may not always be prepared to mate. For example, mating or courtship may be detrimental to its fitness and resistance is expected under these circumstances. As such, various resistance strategies have evolved, from physically fending off courting individuals to producing behavioural signals of unreceptivity. In the parasitoid wasp Spalangia endius, females rarely re-mate and mated females are avoided by males in favour of virgin females. Further, mated females appear to advertise their mating status by the release of a pheromone component (methyl 6-methylsalicylate), but direct evidence of the nature of this release is lacking. Here we used real-time chemical analysis to track the emission of the pheromone component during courtship interactions between virgin males and either virgin or mated females. We found that females actively release methyl 6-methylsalicylate when courted and that significantly greater concentrations are released by previously mated females. Further, high concentrations of this component are associated with both the prevention and termination of courtship.