Cicada Populations Research Articles

МОНИТОРИНГ СОСУЩИХ ВРЕДИТЕЛЕЙ В УСЛОВИЯХ ДОНА

The article provides data on the number of sucking pests in 2022. The research was carried out in the conditions of Novocherkassk branch of the experimental field on the technical varie-ty Cvetochniy. Over the past decade, in the Rostov region, due to changes in climatic con-ditions, as well as with the appearance of a large number of lands overgrown with weeds, sucking pests have moved to grapevine plants. Subsequently, damage by sucking pests leads to a decrease in the yield and quality of grapes. The lack of precipitation in June 2022 and the high temperatures in July are factors that did not favorably affect the prevalence of cicada populations. Chemical treatments with insecti-cides were carried out in a timely manner. The effectiveness of insecticide Kinfos was proved against sucking pests of grapes in vineyards of Rostov region. In order to determine an eco-nomically significant threshold for the number of pest populations and make a decision on protective measures, it is advisable to systemat-ically monitor their prevalence. To predict the development of harmful organisms, it is neces-sary to take into account the meteorological conditions of winter and growing season. Ac-cording to the results of monitoring studies, it was found that in the conditions of 2022, three generations of the roseate cicada and one gen-eration of the humpback buffalo, two genera-tions of the grape thrips developed.

Cicada-MET: an efficient ecological monitoring protocol of cicada populations

Cicadas are a fascinating group of insects that play an essential role in terrestrial ecosystems. Their long-lasting association with plant roots encourages their use as indicators of vegetation and soil integrity. Cicada-MET is a novel, standardized method for monitoring cicada populations by counting cicada exuviae (i.e., the skin of emerged nymphs), providing an effective and efficient means to study their distribution, abundance, and ecology. The method involves annual exuviae counts along transects and fixed plots sampled throughout the emergence season. We validated Cicada-MET using a database of 466 counts from 64 transects over 10 years and the sampling of 60 plots for one season. Methodological aspects tested included sampling speed, exuviae detectability in successive counts, exuviae loss due to weather, and cicada species detection performance using exuviae counts compared to auditory methods. Transects captured approximately 10% of the total number of emerged nymphs across one season, demonstrating the protocol’s reliability in estimating emerging cicada population numbers. However, caution is needed when inferring densities for larger areas, separated from paths where transects are located. The standardized nature of Cicada-MET reduces spatial and temporal biases, allowing for interspecific comparisons and monitoring interannual variations in abundances and emergence timing. This method is well-suited for studying the impact of natural and anthropogenic disturbances. The high-resolution data obtained can be easily combined with environmental variables, enhancing the value of cicada data as bioindicators. In summary, Cicada-MET offers a versatile and efficient tool for monitoring cicada populations, with applications in ecological indication, conservation, and management. The adaptability of Cicada-MET to various research questions, spatial scales, and long-term approaches, along with its quantitative accuracy and ease of use, make it a valuable resource for researchers and practitioners working with cicadas and their associated ecosystems.

Changes in white oak (Quercus alba) phytochemistry in response to periodical cicadas: Before, during, and after an emergence.

Periodical cicadas have mass emergences once every 13 or 17 years. Plants may need to upregulate defense production in response to an emergence. Defense production is energetically expensive, so plants may downregulate their production after periodical cicada populations dissipate. We examined the defensive responses in leaves, branches, and roots of a common host, white oak (Quercus alba), prior to, during, and after a 17‐year periodical cicada (Magicicada spp.) emergence in western Pennsylvania, United States. During the emergence, total tannins and condensed tannins increased in foliar tissue, while simultaneously decreasing in root tissue compared to the prior and subsequent years. Non‐structural carbohydrates were low prior to the mass emergence but were re‐allocated to belowground storage during the emergence year and dropped thereafter. In the year after the emergence, there was a relaxation of foliar defenses, and root defenses returned to pre‐emergence concentrations. We also tested for differences in damaged and undamaged branches on the same tree during (2019) and the year after the emergence (2020). Both damaged and undamaged branches had significantly greater chemical defenses (polyphenols, total tannins, and condensed tannins) during the emergence than in the following year when there was no emergence. We propose that re‐allocation of resources may help maximize oak tree fitness by moving resources away from areas that are not in immediate threat to areas that are under immediate threat. Changes in aboveground and belowground phytochemistry in response to periodical cicada mass emergences may help us better understand which resource re‐allocation strategies are used by plants to minimize the effects of insect emergencies.

Extraoral digestion: outsourcing the role of the hemipteran midgut.

Extraoral digestion allows for breakdown of dietary components before they reach the midgut for final enzymatic degradation and absorption. In the Hemiptera, this is achieved by the secretion of enzyme-rich fluids from the salivary gland, with the combination of protein and mRNA from these tissues termed the sialome. Separate channels within the hemipteran stylets allow for secretion of saliva and ingestion of predigested material in a non-reflux mechanism. Both feeding mode and diet type influence the composition of the hemipteran sialome, as illustrated by 1) differences in protease abundance between hematophagous and predatory heteropteran sialomes, 2) diet specific aminopeptidase-N genes among aphid biotypes, and 3) adaptation-induced sialome variation in related cicada populations. Despite challenges associated with incomplete genome annotation, -omics analysis of the sialomes of diverse hemipteran species will enhance understanding of both sialome function and the evolution of extraoral digestion within the order.

Look closely and listen carefully: unexpected cicada diversity in northern Sardinia, with the description of a new species (Cicadidae: Tibicina)

Abstract Integrative taxonomy combines different data sources as a way to detect separately evolving metapopulation lineages or species. This method is applied to cicada populations found in northern Sardinia, based on acoustic, morphological and ecological data. Thereby, the genus Tibicina turned out to be more diverse than previously expected. Besides the anticipated Tibicina corsica corsica and T. nigronervosa, both scientifically described from the neighbouring island of Corsica, two poorly or previously unknown species have been discovered. Tibicina longisyllaba sp. nov. is here described as new. Tibicina corsica s.l. forms a small species complex where syllable periods of the song – the movement cycle of the acoustic organs – are specific without overlaps. Some coloration and hair cover characters, as well as the shape of the song apparatus, are not diagnostic on their own, but highly significant between species. Species occur sympatrically, parapatrically or allopatrically and prefer specific habitats from grassland to closed forests. All four Tibicina taxa are endemic to parts of Sardinia or to the Corso-Sardinian archipelago. The new findings are important for biodiversity conservation and public awareness. The loud, strident calling songs dominate the summer sounds of the islands. The group could form a showcase with respect to biogeography, phylogeny, speciation and sound production.

Hybridization selects for prime-numbered life cycles in Magicicada: An individual-based simulation model of a structured periodical cicada population.

We investigate competition between separate periodical cicada populations each possessing different life‐cycle lengths. We build an individual‐based model to simulate the cicada life cycle and allow random migrations to occur between patches inhabited by the different populations. We show that if hybridization between different cycle lengths produces offspring that have an intermediate life‐cycle length, then predation acts disproportionately to select against the hybrid offspring. This happens because they emerge in low densities without the safety‐in‐numbers provided by either parent population. Thus, prime‐numbered life cycles that can better avoid hybridization are favored. However, we find that this advantage of prime‐numbered cycles occurs only if there is some mechanism that can occasionally synchronize emergence between local populations in sufficiently many patches.

Psychoactive plant- and mushroom-associated alkaloids from two behavior modifying cicada pathogens.

Entomopathogenic fungi routinely kill their hosts before releasing infectious spores, but a few species keep insects alive while sporulating, which enhances dispersal. Transcriptomics- and metabolomics-based studies of entomopathogens with post-mortem dissemination from their parasitized hosts have unraveled infection processes and host responses. However, the mechanisms underlying active spore transmission by Entomophthoralean fungi in living insects remain elusive. Here we report the discovery, through metabolomics, of the plant-associated amphetamine, cathinone, in four Massospora cicadina-infected periodical cicada populations, and the mushroom-associated tryptamine, psilocybin, in annual cicadas infected with Massospora platypediae or Massospora levispora, which likely represent a single fungal species. The absence of some fungal enzymes necessary for cathinone and psilocybin biosynthesis along with the inability to detect intermediate metabolites or gene orthologs are consistent with possibly novel biosynthesis pathways in Massospora. The neurogenic activities of these compounds suggest the extended phenotype of Massospora that modifies cicada behavior to maximize dissemination is chemically-induced.

Urban heat island effect on cicada densities in metropolitan Seoul.

BackgroundUrban heat island (UHI) effect, the ubiquitous consequence of urbanization, is considered to play a major role in population expansion of numerous insects. Cryptotympana atrata and Hyalessa fuscata are the most abundant cicada species in the Korean Peninsula, where their population densities are higher in urban than in rural areas. We predicted a positive relationship between the UHI intensities and population densities of these two cicada species in metropolitan Seoul.MethodsTo test this prediction, enumeration surveys of cicada exuviae densities were conducted in 36 localities located within and in the vicinity of metropolitan Seoul. Samples were collected in two consecutive periods from July to August 2015. The abundance of each species was estimated by two resource-weighted densities, one based on the total geographic area, and the other on the total number of trees. Multiple linear regression analyses were performed to identify factors critical for the prevalence of cicada species in the urban habitat.ResultsC. atrata and H. fuscata were major constituents of cicada species composition collected across all localities. Minimum temperature and sampling period were significant factors contributing to the variation in densities of both species, whereas other environmental factors related to urbanization were not significant. More cicada exuviae were collected in the second rather than in the first samplings, which matched the phenological pattern of cicadas in metropolitan Seoul. Cicada population densities increased measurably with the increase in temperature. Age of residential complex also exhibited a significantly positive correlation to H. fuscata densities, but not to C. atrata densities.DiscussionEffects of temperature on cicada densities have been discerned from other environmental factors, as cicada densities increased measurably in tandem with elevated temperature. Several mechanisms may contribute to the abundance of cicadas in urban environments, such as higher fecundity of females, lower mortality rate of instars, decline in host plant quality, and local adaptation of organisms, but none of them were tested in the current study.ConclusionsIn sum, results of the enumeration surveys of cicada exuviae support the hypothesis that the UHI effect underlies the population expansion of cicadas in metropolitan Seoul. Nevertheless, the underlying mechanisms for this remain untested.

Delayed effects of fire and logging on cicada nymph abundance

The degradation of the root system after fire and logging entails alteration of belowground biodiversity. Nymphs of Cicada orni feed on the sap of roots and can be indicators of the fate of the root-feeding fauna. I studied the cicada population of a pine forest which was affected in 2010 by a wildfire that burned all the vegetation aboveground and was subsequently logged. I hypothesized that the effect of these disturbances on the forest root system would negatively affect nymph abundance and length, due to the consequent food limitation. I used a BACI (before-after control-impact) design approach, assuming that root degradation, taking place around 1 year after the death of aerial structures, was the main impact on cicada nymphs. Cicada exuviae attached to vegetation were collected as a proxy for nymphs. From 2011 to 2012, the relative abundance of exuviae increased from 12.6 to 23.3 exuviae/100 m2 in the control area, but decreased from 18.0 to 3.6 exuviae/100 m2 in the burned area, probably as a consequence of progressive root degradation and/or to the absence of 2-year-old nymphs due to the destruction of eggs by fire. However, interannual trends in exuviae length of males and females cicadas were not significantly different between areas. This population crash illustrates a previously undescribed time lag in the response of belowground animals to fire and logging which may have consequences for the ecosystem as a whole.

Body Temperature and Responses of Periodical Cicadas (Homoptera: Cicadidae) to a Potential Predator

Brood emergences of periodical cicadas are closely synchronized resulting in a mass emergence which represents an effective anti-predatory response (Lloyd and Dybas, 1966a, b). Not only does the mass emergence swamp the local populations of birds and mammals, but the long interval between emergences (13 or 17 yr) prevents a predator population from tracking these peaks in cicada populations. Furthermore, the chorusing of densely packed males produces a sound level that can deter birds from effective hunting (Simmons et al, 1971). Individual periodical cicadas are nonetheless vulnerable given the ease at which they can be approached (Beamer, 1931; Lloyd and Dybas, 1966b). Local avian predators take substantial numbers as evidenced by the increases in their populations in the year following a mass emergence (Koenig and Liebhold, 2005). Also, small mammals such as voles, mice and shrews show substantial increases of cicadas in their diet during a mass emergence (Hahus and Smith, 1990). Steward et al. (1988) reported that many individual cicadas of the 13-year species (Magicicada spp.) responded actively to an approaching predator by flying away, falling, or by squawking in males. The cicadas changed how they responded over the emergence period; fewer individuals remained stationary after the period of peak density compared with before, and more males squawked as a part of their response near the end than at the start of emergence. The present study was intended to determine how 17-year cicadas, Magicicada cassini Fisch (Homoptera: Cicadidae), would respond to a model avian predator and to compare their responses to that reported in the literature for 13-year cicadas. Even though a periodical cicada can fly when its body temperature is above 19 °C (Heath, 1967), its body temperature may affect its decision of when to escape by flying. Several species of lizards respond differently to an approaching predator at varying body temperatures (Huey, 1982; Cooper, 2000, 2006). Therefore, the body temperature of each cicada was recorded along with its response.

Comparison of cold tolerance in eggs of two cicadas, Cryptotympana facialis and Graptopsaltria nigrofuscata, in relation to climate warming

AbstractThe population of the cicada Cryptotympana facialis began to increase in Osaka, Japan, during the late 20th century. Climate warming is considered a major cause, although the relationship between temperature and the cicada population increase remains unclear. By examining cold tolerance in overwintering eggs of C. facialis in relation to another cicada, Graptopsaltria nigrofuscata, whose population has recently decreased in Osaka, we tested the hypothesis that warming has caused the population increase of C. facialis by decreasing egg mortality due to winter temperatures. A short‐term (24 h) cold exposure experiment demonstrated that the half‐lethal temperatures (LT50) of C. facialis and G. nigrofuscata were −23.3°C and −28.9°C, respectively, although these extreme low temperatures never occurred in Osaka during the 20th century. Prolonged exposure to −5°C for up to 30 days had no harmful effects on the hatching rate in either species. Overwintering mortality was also assessed under naturally fluctuating conditions by transferring eggs to cooler elevated sites that mimicked the environment prior to the current warming. Eggs of C. facialis that overwintered at the cooler site exhibited similar hatching rates to those maintained at the original site. The results of these experiments consistently indicated that overwintering eggs of C. facialis possess adequate tolerance to the low temperatures of the 20th century. Therefore, we rejected our initial hypothesis that recent increases in the C. facialis population have been caused by warming‐related reductions in overwintering egg mortality.

Does the periodical cicada, Magicicada septendecim, prefer to oviposit on native or exotic plant species?

Abstract 1. In 2004, Brood X of the periodical cicada (Magicicada spp.) emerged in Delaware. Extensive suburban development and concomitant planting of exotic species has occurred since the previous emergence of Brood X in 1987.2. Exotic species could suffer extensive damage during years of cicada emergences if they are preferred for oviposition. Alternately, a shortage of suitable plant hosts may negatively affect remaining cicada populations.3. We determined if the periodical cicada, Magicicada septendecim, preferred to oviposit on native or exotic woody plant species. Potential hosts were divided into three groups and planted in a randomised design near a likely source of cicadas. The first group, Natives, included 15 species native to Delaware. The second group, Non‐natives, included 15 exotic species that had a native congener represented in the Native group. The final group, Aliens, included 13 exotic species that did not have a native congener.4. Based on observations of 428 plants, cicadas were more likely to oviposit on Natives or Non‐natives, which did not differ from each other in this measure, than on Aliens. Non‐natives had more oviposition holes per metre than Natives, which had more holes per metre than Aliens. The likelihood of stem flagging was lowest on Alien species; the percentage of the total plant that flagged was greatest for Natives. Plant morphology also influenced host preference and likelihood of flagging.5. Taking plant morphology into consideration, we speculate that the evolutionary history between periodical cicadas and potential hosts is an important component of host preference.

A COMMENT ON GENE INTROGRESSION VERSUS EN MASSE CYCLE SWITCHING IN THE EVOLUTION OF 13-YEAR AND 17-YEAR LIFE CYCLES IN PERIODICAL CICADAS

In companion papers, Simon et al. (2000) and Marshall and Cooley (2000) discuss geographic distributions of phenotypic characters and genetic markers of Magicicada decim spp. in the lower Mississippi valley and vicinity. Periodical cicadas (Magicicada spp.) of eastern North America have spurred many debates concerning the evolutionary origin of their unusual 13-year and 17-year life cycles, and instantaneous speciation through en masse cycle switching has been a recurring hypothesis. En masse switching both from 13to 17-year cycles and from 17to 13-year cycles are components of the cycle-switching model of Magicicada evolution (e.g., Lloyd and Dybas 1966a, 1966b; Lloyd and White 1976; Simon 1979, 1988; Martin and Simon 1988, 1990; Williams and Simon 1995). The new field data of Marshall and Cooley (2000) document character displacement between 13-year cicadas with genotypes similar to northern 17-year populations, and sympatric 13-year cicadas with genotypes similar to southern 13-year populations. Simon et al. (2000) interpret this character displacement and other new genetic data as support for the hypothesis of instantaneous speciation by en masse cycle switching from 17to 13-year cycles. However, it is our view that these authors do not adequately explore conventional gene flow explanations of the observed phenotypic and genetic variation that do not require en masse cycle switching. Evaluation of these competing hypotheses can benefit from an interdisciplinary perspective incorporating paleoecological data. We (Cox and Carlton 1988, 1991, 1998; Cox 1992) previously proposed an alternative selection-gene introgression model for Magicicada evolution incorporating paleoecological reconstructions that also explains these new genetic and phenotypic observations of Simon et al. (2000) and Marshall and Cooley (2000). Our hypothesis offers an important caveat about the use of mtDNA in certain circumstances to interpret the magnitude of gene flow between populations and evolutionary processes. We hypothesize unidirectional gene flow via dispersing male cicadas that transferred limited nuclear DNA and no mtDNA to the recipient population. In brief, our model presented in Cox and Carlton (1988) proposes that life-cycle timing differences between cicada populations arose not from en masse cycle switching, but from stochastic selection processes involving Magicicada temperature thresholds, Pleistocene climate characteristics, and hybridization frequencies between populations having a spectrum of life-cycle lengths. Heath (1967, 1968) reports that periodical cicadas emerge from their burrows when soil temperature is 64.3?F and that the air temperature must reach 68?F for flight and mating. In our quantitative model, during glacial maximum it was much more common than it is now for summers to remain too cold for ancestral periodical cicadas to emerge and/or mate, and the ancestors of periodical cicada populations must have failed to reproduce during those years. This seasonal capriciousness gave rise to periodicity (years without cicadas) and selection of long life cycles (conferring a reduced chance of emerging on a cool summer). By the parameters of our model, selected life cycles would be ? 12 years and would be longer in colder climates. This aspect of our model explains the climatically correlated zonation of Magicicada life cycles (Fig. 1). Once periodicity and long life cycles were established, satiation of predators by synchronized emergence became an important strategy for periodical cicadas. Predator satiation works best with precisely synchronized periodicity, and cycle synchronization is diminished by increased heterozygosity. Thus, cicadas that are hybrids of two populations with different cycle lengths will suffer greater predation losses, as many may emerge on years before or after the main population. Cicadas with prime-numbered cycles (13 years and 17 years) will hybridize significantly less frequently than cicadas with non-prime (composite) cycles and thus will have larger emergences and a greater advantage of predator satiation. See Cox and Carlton (1988) for a full discussion of this topic. Marshall and Cooley (2000) studied M. decim spp. of southern 13-year Brood XIX (each brood consists of all synchronized individuals) within the contact zone with more northern 17-year broods (M. septendecim). These authors document character displacement of call pitch between male 13year cicadas with abdominal coloration like cicadas of contiguous 17-year populations (new 13-year cicadas, M. neotredecim) and sympatric male 13-year cicadas with coloration like contiguous Brood XIX populations in the lower Mississippi valley (old 13-year cicadas, M. tredecim). Marshall and Cooley (2000, see their Figs. 4 and 9) argue that M. tredecim have never been present within the range M. neotredecim north of the contact zone and that these two species have hybridized only along the contact zone at the southern margin of the M. neotredecim range. The steep gradient in call pitch frequency along the southern margin of M. neo-

Spatial and ecological isolation in cicadas: First data from Tibicina (Hemiptera: Cicadoidea) in France

The seven taxa of the cicada genus Tibicina (T.corsica corsica, T. corsica fairmairei, T. garricola, T. haematodes, T. nigronervosa, T. quadrisignata, T. tomentosa) which occur in continental France and Corsica were investigated. Extrinsic factors (geographical barriers) and factors intrinsic to the ecology of species were considered in an effort to understand the biogeography of Tibicina. Three patterns related to intrinsic factors were recognised: (1) pairs of taxa with sympatric distributions but with divergent habitat preferences; (2) pairs of taxa with sympatric distributions and similar habitat but with allochronic occurrence; (3) pairs of taxa with similar ecology but with allopatric distributions. When taxa were separated by their habitat, the height of vegetation appeared to be more important than the floristic composition of the habitat. These factors lead to the partitioning of resources in time and space. All taxa occur in secondary vegetations. Human agro-pastoral activity has probably influenced the dynamics of cicada populations and the maintenance of isolation between them.

Ontogenetic Scaling of Foraging Rates and the Dynamics of a Size-Structured Consumer-Resource Model

The ontogenetic scaling of foraging capacity strongly influences the competitive ability of differently sized individuals within a species. We develop a physiologically structured model to investigate the effect of different ontogenetic size scalings of the attack rate on the population dynamics of a consumer-resource system. The resource is assumed to reproduce continuously whereas the consumer only reproduces at discrete time instants. Depending on the ontogenetic size scaling, the model exhibited recruit-driven cycles, stable fixed point dynamics, non-recruit juvenile-driven cycles, quasiperiodic orbits, or chaotic dynamics. The kind of dynamics observed was related to the maintenance resource levels required of differently sized individuals. Stable fixed point dynamics was, besides at the persistence boundary, only observed when the minimum resource levels were similar for newborns and mature individuals. The tendency for large population fluctuations over a wide range of the parameter space was due to the consumer's pulsed reproduction. Background mortality and length of season were major determinants of cycle length. Model dynamics strongly resembled empirically observed dynamics from fish and Daphnia populations with respect to both patterns and mechanisms. The non-recruit juvenile-driven dynamics is suggested to occur in populations with size-dependent interference or preemptive competition like cicada populations.

Role of Escape from Predators in Periodical Cicada (Homoptera: Cicadidae) Cycles

Evolution of unusually long life cycles and synchronized emergence of periodical cicadas, Magicicada spp., is one of the mysterious problems in evolutionary biology. Yoshimura presented a hypothesis to explain this by the elongation of the life cycle during glacial periods and the extinction of some yearclasses because of difficulty of mating in years of low adult density. Yoshimura assumes large fluctuations of abundance in ancient cicada populations, but cicada populations are far more stable than those of many other insects. By examining such data, I concluded that escape from predator pressure by synchronized massemergence is the most important factor for the evolution and maintenance of long-year periodicity, which has so far been found only in cicadas.

Eco-Friendly Coffee Farming

Letters from: Laura Tangley accurately details the need for U.S. consumers to think about how their coffee is produced and the importance of “certified eco-friendly” coffee to the conservation of migratory songbirds (“The case of the missing migrants,” (Research News, [22 Nov., p. 1299][1]). However, we would like to make clear that our ECO-O.K. Coffee Certification Program requires that coffee be grown beneath a diverse canopy of native tree species. ECO-O.K. certifies either organic farms or those that use integrated pest management. When a producer must use agrochemicals to save his or her crop, our standards strictly control the transport, storage, and use of the chemicals, thus reducing threats to the environment and human health. While forested organic coffee farms offer perhaps the best example of bird-friendly production, they occupy only a tiny percentage of coffee-growing lands. The Rainforest Alliance wants to promote large numbers of forested coffee farms in order to have maximum conservation impact. By pursuing this strategy, we believe that we can stop and perhaps even reverse the trend toward damaging, “full-sun” coffee fields. # {#article-title-2} Tangley's commentary concerning the mounting deleterious impact of changing methods of shade usage, or lack thereof, in coffee plantations on migratory bird populations calls attention to my previously published data sets on cicada populations thriving in some Costa Rican coffee plantations ([1][2], [2][3]). Costa Rican coffee plantations, in my experience, support several genera and species of cicadas of varying body size, behaviors, and seasonal emergence patterns. Furthermore, a large percentage of the total cicada fauna of Costa Rica (a total of about 30 species) thrives in those coffee habitats in which various legume trees—especially of the genera Inga , Erythrina , and Pithecollobium —are used as shade cover ([1][2]). Repeated surveys of emerging cicadas in these coffee habitats reveal a discernibly patchy spatial distribution, as indicated by the locations of final molt-cast nymphal skins clustered near these shade trees rather than evenly distributed across the coffee bushes. Cicada nymphs drench sap subterraneously from tree roots for several years before maturing and emerging from the soil for the molt to the winged adult stage. In some instances, the densities of cicada-cast skins in coffee habitats can be considerably higher than in comparable areas of adjacent wet or moist forest habitats. Such data suggest a larger biomass of adult cicadas being present in coffee plantations with legume and other tree shade cover, very likely providing an ample food supply for insectivorous birds. What is especially notable about these patterns is the high numbers of cicadas emerging in Costa Rica's premier coffee-growing zone within the pronounced tropical dry season, a period corresponding to the winter season of the northern hemisphere. Therefore, dry-season cicadas undoubtedly comprise a portion of the diet for migratory bird species inhabiting these areas temporarily as well. 1. 1.[↵][4] 1. A. M. Young , Am. Midl. Nat. 103, 155 (1980); [OpenUrl][5][CrossRef][6][Web of Science][7] J. N.Y. Entomol. Soc. 89, 123 (1981). [OpenUrl][8] 2. 2.[↵][9] 1. A. M. Young , Milw. Publ. Mus. Contrib. Biol. Geol. 40, 1 (1981). [OpenUrl][10] [1]: /lookup/volpage/275/1299 [2]: #ref-1 [3]: #ref-2 [4]: #xref-ref-1-1 View reference 1. in text [5]: {openurl}?query=rft.jtitle%253DAm.%2BMidl.%2BNat.%26rft.volume%253D103%26rft.spage%253D155%26rft.atitle%253DAM%2BMIDL%2BNAT%26rft_id%253Dinfo%253Adoi%252F10.2307%252F2425049%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [6]: /lookup/external-ref?access_num=10.2307/2425049&link_type=DOI [7]: /lookup/external-ref?access_num=A1980JD72100017&link_type=ISI [8]: {openurl}?query=rft.jtitle%253DJ.%2BN.Y.%2BEntomol.%2BSoc.%26rft.volume%253D89%26rft.spage%253D123%26rft.atitle%253DJ%2BNY%2BENTOMOL%2BSOC%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [9]: #xref-ref-2-1 View reference 2. in text [10]: {openurl}?query=rft.jtitle%253DMilw.%2BPubl.%2BMus.%2BContrib.%2BBiol.%2BGeol.%26rft.volume%253D40%26rft.spage%253D1%26rft.atitle%253DMILW%2BPUBL%2BMUS%2BCONTRIB%2BBIOL%2BGEOL%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx

Emergence of 13‐Yr Periodical Cicadas (Cicadidae: Magicicada): Phenology, Mortality, and Predators Satiation

We examined emergence of male and female 13—yr periodical cicadas (Brood XIX) and mortality, due to avain predation, fungal infection (Massospora cicadina), environmental factors, and senescence. We compared relative contributions of the sources of mortality, and determined the temporal pattern of avian predation associated with predator satiation and mortality. Based on a mean density of 6.65 emergence holes/m2, we estimated that 1 063 300 cicadas emerged on our 16—ha study area in northwestern Arkansas during May 1985. Males appeared first in emergence traps in early May and emerged more synchronously than did females. About 50% of the population emerged during four consecutive nights, and peak abundance of adult cicadas occurred in late May. Based on samples from mortality traps, at least 40% of the population died in severe thunderstorms during the first week of June, demonstrating the stochastic factors can be major influences on periodical cicada populations. Fungal infection was not a major source of mortality. The first cicadas that emerged in early May were eaten by birds, but avian predators became satiated. Birds consumed 15—40% of the standing crop at low cicada densities, but very little of the standing crop was consumed when cicada densities were >24 000 individuals/ha on the study site. Avian predators appeared to be satiated for several weeks, and by the time their foraging activities increased due to demands imposed by feeding young, density of adult cicadas was relatively low. Mortality due to predation gradually increased to near 100% as the density of adult cicadas declined in June. Based on estimates of cicada emergence and deaths due to avian predation where adult cicada activity was greatest, birds consumed only °15% of the adult cicada population. Therefore, only a small proportion of the adult cicada population was actually consumed by avian predators. These results demonstrate that, indeed, the synchronized, explosive emergences of periodical cicadas may be classical examples of predator satiation.

Radionuclide Contamination as an Influence on the Morphology and Genetic Structure of Periodical Cicada (Magicicada cassini) Populations

-Horizontal starch gel electrophoresis of enzymes and multivariate analysis of morphometric variations were used to compare the genetic structure of cicada populations, Magicicada cassini, collected from a radionuclide contaminated site with those collected from four reference sites. Homogeneity was observed between sites at the phosphoglucomutase (P?GM) and alpha-glycerophosphate dehydrogenase (a-GPDH) loci. Heterogeneity was found among populations within the contaminated site at the a-GPDH loci. The esterase (EST-2,3,5) loci examined were heterogeneous between sites and among populations. With few exceptions little morphometric variation was discovered between cicada populations. However, more morphometric variation was observed among populations within sites. The data indicate that population genetic structure of cicadas from the uranium production facility was not affected by soil contamination. Morphological patterns were unique in cicadas from one population at the facility.

Red-winged blackbird predation on periodical cicadas (Cicadidae: Magicicada spp.): bird behavior and cicada responses.

Predation by red-winged blackbirds Agelaius phoeniceus L. on 13-year periodical cicadas (Magicicada spp.) and reactions by periodical cicadas to predators were studied during emergence of Brood XIX during summer of 1985 in northwestern Arkansas (USA). Emergences of periodical cicadas are classic examples of predator satiation due to high local densities of cicadas and birds are the major predators of adult periodical cicadas. Reactions of periodical cicadas to predators were assessed by recording behaviors exhibited by cicadas when approached in trees by a human hand during the 3-week period of peak adult densitics. Most male cicadas made a noise in association with escape behaviors when approached, and 50% of the females, which are silent, attempted escape behaviors. Observations of predation attempts on cicadas by red-winged blackbirds were made during the period of peak predation pressure. Red-winged blackbirds spent less time searching for cicadas over that 2-week period of increasing predation pressure, and became increasingly efficient at capturing cicadas. Handling time of cicadas by red-winged blackbirds increased by about 20 seconds over that period, as blackbirds spent more time consuming female cicadas. The flysquawk response, used only by male cicadas, was effective in deterring red-winged blackbirds; only 5% of the attacks by blackbirds were successful when that behavior was exhibited. All cicadas that remained motionless and silent when approached by blackbirds were captured and consumed. Because females remained inactive when approached more often than did males, blackbirds may have consumed more female cicadas. Changes that appeared in reactions of preiodical cicadas to the model predator and to the attacks of blackbirds reflect both changes in the sex ratio of the cicada populations and changes in behaviors of cicadas associated with mating and egg laying. The loud noise made by male periodical cicadas at mating centers did not appear to deter predation by blackbirds. Changes in the behavior of blackbirds that appeared to be in association with greater predation on female periodical cicadas relates directly to aspects of foraging theory, particularly predictions concerning more selective foraging during periods of abundant food resources.