Periodical Cicadas Research Articles

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.

Deposition and decomposition of periodical cicadas (Homoptera: Cicadidae:Magicicada) in woodland aquatic ecosystems

Many freshwater ecosystems receive allochthonous resource subsidies from adjacent terrestrial environments. In eastern North American forests, geographic broods of periodical cicadas emerge every 13 to 17 y to breed, and local abundances can sometimes be >300 individuals/m2. Most individuals avoid predation, senesce after breeding, and become a resource pulse for forest ecosystems; some cicada carcasses enter freshwater ecosystems where they represent a detrital resource pulse. Here, we present a 2-part study in which we examined the deposition of cicada detritus into woodland ponds and low-order streams in southwestern Ohio during the emergence of Brood X periodical cicadas. We compared the deposition of nutrients associated with periodical cicada detritus and terrestrial leaf litter into small woodland ponds and low-order streams. We used a laboratory experiment to compare patterns of decomposition and nutrient release of adult periodical cicada carcasses and sycamore leaf litter. Input of periodical cicada detritus to woodland streams and ponds was a function of local cicada emergence densities. Organic C loading to woodland aquatic ecosystems from cicada detritus was substantially less than that from terrestrial leaf litter; however, the higher mass-specific N and P content of cicada material made cicada detritus a relatively important nutrient input. N and P deposited in cicada detritus represented 0.2 to 61% of the N and 0.3 to 50% of the P deposited into woodland aquatic ecosystems via terrestrial leaf litter. Decomposition experiments indicated that cicada detritus was of much higher quality than was sycamore leaf litter; female and male cicada carcasses lost mass at significantly faster rates than sycamore leaves (female k = −0.05/d, male k = −0.04/d, sycamore leaf k = −0.002/d). Release rates of C, N, and P from cicada carcasses were 4, 39, and 150× greater, respectively, than release rates from sycamore leaves. Our study indicates that periodical cicada detritus can represent a substantial allochthonous resource pulse to forested aquatic ecosystems and that cicada detritus is of substantially higher quality than is terrestrial leaf litter. These results suggest that deposition and decomposition of periodical cicada detritus can affect the productivity and dynamics of woodland aquatic ecosystems and that the role of animal-derived resource pulses to ecosystems requires further exploration.

Differential susceptibility of tree species to oviposition by periodical cicadas

Abstract 1. Periodical cicadas occur widely in deciduous forests of eastern North America and represent the largest insect emergences in the world. Their effects on forest community dynamics, via oviposition damage and root feeding, are potentially great but not well understood. If tree species vary in their susceptibility to cicada oviposition and root colonization, then periodical cicadas may affect ecological interactions among tree species and forest composition.2. We measured oviposition damage on 63 tree species at 52 sites in southern Indiana, U.S.A. for two broods of periodical cicadas. We compared oviposition damage among different sites, habitats, and tree species. We also measured cicada emergence rates in mature and successional forest habitats and from beneath different tree species.3. Certain tree species received significantly more oviposition damage than others, and the most and least damaged species were consistent between the two broods. For some species, oviposition damage varied between mature and successional sites. Despite the differences in oviposition rates among species, there was no difference in emergence rates from beneath different tree species, suggesting that initial differences in cicada density among tree species are not maintained through the nymphal life cycle.4. Cicadas oviposited more at successional sites, but emerged more in mature forest stands, suggesting that successive generations of cicadas represent a shifting mosaic between forests of different ages. As tree species consistently vary in their susceptibility to oviposition damage, periodical cicadas could alter local competitive interactions and therefore affect forest dynamics.

The Distribution of Periodical Cicada Brood X in 2004

American Entomologist • Summer 2009 P eriodical cicadas (genus Magicicada) are found only in eastern North America and are notable for their long, primenumbered life cycles, precisely timed mass emergences, and dense, multispecies choruses. Their uniqueness has given them a special appeal and cultural status. Members of the Onondaga Nation maintain the oral tradition of being rescued from famine by periodical cicadas (Cooley et al. 2004). Early European colonists viewed periodical cicadas with a mixture of religious apprehension and loathing (Kritsky 2004); and modern Americans maintain numerous Web sites to assist in planning weddings, graduations, and other outdoor activities around Magicicada emergences (e.g., cicadamania.com). Periodical cicadas have attracted the attention

Long‐Term Habitat Selection and Chronic Root Herbivory: Explaining the Relationship between Periodical Cicada Density and Tree Growth

Periodical cicadas (Magicicada spp.) are insect herbivores that feed on host tree roots, but their distribution among hosts is determined largely by the oviposition of female cicadas in the previous generation. A pattern of decreasing tree growth rates with increasing cicada densities is predicted when considering the costs of chronic root herbivory, but the opposite pattern is expected when considering adaptive habitat selection. Here, we report observations indicating that the relationship between periodical cicada densities and host tree growth rates is hump shaped. We suggest that both herbivory and habitat selection are likely to be key processes explaining this pattern, resulting in regions of positive and negative correlation. These results suggest that the effects of cicada herbivory are most apparent at relatively high cicada densities, while habitat selection tends to distribute cicada herbivory on host trees that are able to compensate for cicada root herbivory up to threshold cicada densities.

Dynamics of a neutral delay equation for an insect population with long larval and short adult phases

We present a global study on the stability of the equilibria in a nonlinear autonomous neutral delay differential population model formulated by Bocharov and Hadeler. This model may be suitable for describing the intriguing dynamics of an insect population with long larval and short adult phases such as the periodical cicada. We circumvent the usual difficulties associated with the study of the stability of a nonlinear neutral delay differential model by transforming it to an appropriate non-neutral nonautonomous delay differential equation with unbounded delay. In the case that no juveniles give birth, we establish the positivity and boundedness of solutions by ad hoc methods and global stability of the extinction and positive equilibria by the method of iteration. We also show that if the time adjusted instantaneous birth rate at the time of maturation is greater than 1, then the population will grow without bound, regardless of the population death process.

Response to enrichment, type and timing: small mammals vary in their response to a springtime cicada but not a carbohydrate pulse

1. Masting events in the autumn provide a carbohydrate-rich pulse of resources that can influence the dynamics of small mammals and their natural enemies. Similar patterns are observed with the periodical cicada emergence which provides a protein-rich pulse in the spring, but comparisons are confounded by timing and food type. 2. We compared the influence of a naturally occurring spring pulse of cicadas with an experimental spring pulse of carbohydrate-rich seeds. We used a replicated population level field experiment and capture-mark-recapture techniques to record the vital rates, demographics, and abundance of Peromyscus leucopus (the white-footed mouse), as well as other small mammals and their parasites. 3. The density of P. leucopus on grids where cicadas emerged was 55% higher than controls as a consequence of early breeding. This was followed by an increase in the prevalence of the nematode Pterygodermatities peromysci, reduced breeding and decreased recruitment rates. Other small mammals including Tamias striatus (eastern chipmunk) and Blarina brevicauda (short-tailed shrew), increased in density, but there was no affect on Sorex cinereus (masked shrew). 4. In contrast to the presence of cicadas, there was no influence of sunflower seed supplementation on small mammal density, vital rates, or reproduction with the exception of an increase in B. brevicauda density. The response of small mammals to seasonal pulses depends on timing, food type, and species.

SELECTION FOR PRIME-NUMBER INTERVALS IN A NUMERICAL MODEL OF PERIODICAL CICADA EVOLUTION

Periodical cicadas are known for unusually long and prime-numbered life cycles (13 and 17 years) for insects. To explain the evolution of prime-numbered reproductive intervals (life cycles), the hybridization hypothesis claims that prime numbers greatly reduce the chance of hybridization with other life cycles. We investigate the hybridization hypothesis using a simulation model. This model is a deterministic, discrete population model with three parameters: larval survival per year, clutch size, and emergence success. Reproductive intervals from 10 years to 20 years compete for survival in the simulations. The model makes three key assumptions: a Mendelian genetic system, random mating among broods of different life-cycle lengths, and integer population sizes. Longer life cycles have larger clutch sizes but suffer higher total mortality than shorter life cycles. Our results show that (1) nonprime-numbered reproductive intervals disappear rapidly in comparison to the selection among the various prime-numbered life cycles, (2) the selection of prime-numbered intervals happens only when populations are at the verge of extinction, and (3) the 13- and 17-year prime phenotypes evolve under certain conditions of the model and may coexist. The hybridization hypothesis is discussed in light of other hypotheses for the evolution of periodical cicada life cycles.

Prey Selection of Big Brown Bats (Eptesicus Fuscus) During an Emergence of 17-Year Cicadas (Magicicada Spp.)

We examined the diet of big brown bats (Eptesicus fuscus) during an emergence of 17-y cicadas (Magicicada spp.) in May and Jun. of 2004 in Indiana. We collected guano from a maternity colony of big brown bats and compared the diet during the cicada emergence to the diet during the same period of a non-cicada year. In contrast to previous studies, homopterans (predominantly 17-y cicadas) were a common food item (22.9–23.6% volume) during the peak of cicada abundance. Scarabaeidae (13.8–48.5%), Carabidae (7.3–36.9%) and hemipterans (19.4–29.3%) were also common prey items during the cicada emergence. Although periodical cicadas constituted a fair amount of the diet during the emergence, the dietary diversity of big brown bats during the emergence was similar to that of non-cicada years. Our results demonstrate that big brown bats forage on 17-y cicadas during a cicada emergence. However, despite the superabundance of cicadas, big brown bats do not specialize on cicadas to the relative exclusion of other prey types.

Periodical Cicada Detritus Impacts Stream Ecosystem Metabolism

The emergence of 17-year periodical cicadas in Maryland, USA, in 2004 provided a unique opportunity to study the effect of a large, but temporally limited, resource pulse of arthropod detritus on stream ecosystem function. Cicada emergence was quantified in the forests adjacent to two small streams with different histories of riparian disturbance (Intact and Disturbed sites). We estimated the input of cicada detritus to the streams, described its retention and breakdown dynamics, and measured whole-stream respiration over the cicada flight season (May–July). Average emergence density was significantly greater at the Intact site, but average cicada detritus input rates were greater at the Disturbed site. Cicada detritus was locally retained within both streams and rapidly broke down. Daily whole-stream respiration (CR24) at both sites responded dramatically to the cicada pulse, with CR24 doubling pre-cicada measurements following the period of greatest cicada input (Intact: 12.82 → 23.78 g O2 m−2 d−1; Disturbed: 2.76 → 5.77 g O2 m−2 d−1). CR24 returned to baseline levels when cicada input decreased at the Intact site, but more than doubled again at the Disturbed site (13.14 g O2 m−2 d−1), despite a decline in cicada input rate. Differences in respiration response may be a function of differences in cicada input rates as well as differences in microbial community activity. The strong effects on stream ecosystem function exerted by a short but intense input of periodical cicada detritus may provide insights regarding the response of streams to other irregular resource pulses.

Eastern Coyotes, <em>Canis latrans</em>, Observed Feeding on Periodical Cicadas, <em>Magicicada septendecim</em>

Eastern Coyotes (Canis latrans) were observed feeding on Periodical Cicadas (Magicicada septendecim) during their once every 17 year emergence (for three weeks) in June 2008.

PULSES OF DEAD PERIODICAL CICADAS INCREASE HERBIVORY OF AMERICAN BELLFLOWERS

Resource pulses can have both direct bottom-up and indirect top-down effects on their consumers, but comparatively few studies have investigated the top-down effects of naturally occurring resource pulses on plants. This study describes two years of field experiments conducted to determine the indirect effects of 17-year periodical cicadas (Magicicada spp.) on herbivory in American bellflowers (Campanulastrum americanum). In 2004, the area of damaged leaves on cicada-supplemented plants was 78% greater than the area of damaged leaves on control plants. In 2005, cicada-supplemented plants were more likely to experience herbivory by mammalian herbivores than control plants. When large herbivores were excluded, similar patterns of leaf herbivory were observed, but these differences were not statistically significant. These results suggest that the pulsed input of dead periodical cicada bodies increased rates of herbivory on bellflowers, and that this effect was largely mediated by the selective foraging of large mammalian herbivores. More broadly, this study suggests that pulses of limiting resources can have both positive direct effects on plants and negative indirect effects due to selective herbivory, and that the net effects of pulsed resources on plants may depend on the composition and behavior of the surrounding herbivore community.

Response of host plants to periodical cicada oviposition damage

Insect oviposition on plants is widespread across many systems, but studies on the response of host plants to oviposition damage are lacking. Although patterns of oviposition vary spatially and temporally, ovipositing insects that exhibit outbreak characteristics may have strong effects on host plants during peak abundance. Periodical cicadas (Magicicada spp.), in particular, may reduce the performance of host plants when they synchronously emerge in massive numbers to mate and oviposit on host plants. Here we provide the first experimental manipulation of host plant use by periodical cicadas to evaluate the impact of cicada oviposition on plant performance across a diversity of host species within an ecologically relevant setting. Using a randomized block design, we established a plantation of three native and three exotic host plant species common to the successional forests in which cicadas occur. During the emergence of Brood X in 2004, we employed a highly effective cicada exclusion treatment by netting half of the host plants within each block. We assessed multiple measures of host plant performance, including overall plant growth and the growth and reproduction of individual branches, across three growing seasons. Despite our thorough assessment of potential host plant responses to oviposition damage, cicada oviposition did not generally inhibit host plant performance. Oviposition densities on unnetted host plants were comparable to levels documented in other studies, reinforcing the ecological relevance of our results, which indicate that cicada oviposition damage did not generally reduce the performance of native or exotic host plants.

COMPARING RESOURCE PULSES IN AQUATIC AND TERRESTRIAL ECOSYSTEMS

Resource pulses affect productivity and dynamics in a diversity of ecosystems, including islands, forests, streams, and lakes. Terrestrial and aquatic systems differ in food web structure and biogeochemistry; thus they may also differ in their responses to resource pulses. However, there has been a limited attempt to compare responses across ecosystem types. Here, we identify similarities and differences in the causes and consequences of resource pulses in terrestrial and aquatic systems. We propose that different patterns of food web and ecosystem structure in terrestrial and aquatic systems lead to different responses to resource pulses. Two predictions emerge from a comparison of resource pulses in the literature: (1) the bottom-up effects of resource pulses should transmit through aquatic food webs faster because of differences in the growth rates, life history, and stoichiometry of organisms in aquatic vs. terrestrial systems, and (2) the impacts of resource pulses should also persist longer in terrestrial systems because of longer generation times, the long-lived nature of many terrestrial resource pulses, and reduced top-down effects of consumers in terrestrial systems compared to aquatic systems. To examine these predictions, we use a case study of a resource pulse that affects both terrestrial and aquatic systems: the synchronous emergence of periodical cicadas (Magicicada spp.) in eastern North American forests. In general, studies that have examined the effects of periodical cicadas on terrestrial and aquatic systems support the prediction that resource pulses transmit more rapidly in aquatic systems; however, support for the prediction that resource pulse effects persist longer in terrestrial systems is equivocal. We conclude that there is a need to elucidate the indirect effects and long-term implications of resource pulses in both terrestrial and aquatic ecosystems.

Sound recordings from the 2007 emergence of Brood XIII cicada

Level calibrated recordings of the Brood XIII 17-year periodic cicadas were made in June, 2007 in River Forest, Illinois. Brood XIII consists of three separate species: Magicicada cassini, M. septendecim, and the more rare M. septendecula. Power spectrum analysis of a 2 min segment of the recording shows a 5.95 kHz resonance with Q≊6, indicative of cassini, and a 5 dB lower resonance at 1.35 kHz with a Q≊13.5, indicative of septendecim. Since other researchers have estimated that the power of septendecim is 20 dB below that of cassini, the high level of the septendecim song suggests that 30 times more septendecim than cassini were singing. Computation of the sound pressure level shows a 2–5 dB variation with a period of 7.5 s, indicative of synchronized chorus singing of cassini.

Population dynamics of a generalist rodent in relation to variability in pulsed food resources in a fragmented landscape

1. Pulsed food resources are often considered equivalent in their potential impact on the reproduction and population dynamics of consumers, but differences in the attributes of food pulses and their distribution in the landscape may cause differences in their effects. 2. We tested whether a perishable pulsed resource (periodical cicadas, Magicicada spp.) had similar effects on the population dynamics of a generalist forest rodent, Peromyscus leucopus, as have been reported for a cacheable pulsed resource (acorn mast). 3. Because the availability of periodical cicadas may vary between edge and interior habitat, we also tested whether habitat type (edge vs. interior) and fragment size affected the abundance of cicadas and P. leucopus. 4. Nearly 90% of the variation in the relative population densities of P. leucopus was explained by the variation in the relative densities of periodical cicadas, and fragments with more cicadas tended to have more reproductive female mice and litters. 5. We found more cicadas and more P. leucopus in edge than interior habitat, but no differences in the relative densities of either in relation to fragment size. 6. Data from a non-emergence year revealed no differences other than the presence of periodical cicadas that could explain the 50% higher relative densities of P. leucopus in the emergence year. 7. At the beginning of the emergence of periodical cicadas, the three fragments with the highest numbers of emergence holes had three times more mice than the fragments with the lowest numbers of emergence holes, suggesting that P. leucopus is able to anticipate the emergence of periodical cicadas and increase reproduction prior to the pulse. 8. Hence, despite differences in perishability, seasonal timing and nutritional quality of pulsed food resources in a fragmented landscape, they appear to have similar positive effects on the population dynamics of the generalist rodent, P. leucopus and, in fact, P. leucopus may be able to anticipate resource pulses.

Evidence for Paternal Leakage in Hybrid Periodical Cicadas (Hemiptera: Magicicada spp.)

Mitochondrial inheritance is generally assumed to be maternal. However, there is increasing evidence of exceptions to this rule, especially in hybrid crosses. In these cases, mitochondria are also inherited paternally, so “paternal leakage” of mitochondria occurs. It is important to understand these exceptions better, since they potentially complicate or invalidate studies that make use of mitochondrial markers. We surveyed F1 offspring of experimental hybrid crosses of the 17-year periodical cicadas Magicicada septendecim, M. septendecula, and M. cassini for the presence of paternal mitochondrial markers at various times during development (1-day eggs; 3-, 6-, 9-week eggs; 16-month old 1st and 2nd instar nymphs). We found evidence of paternal leakage in both reciprocal hybrid crosses in all of these samples. The relative difficulty of detecting paternal mtDNA in the youngest eggs and ease of detecting leakage in older eggs and in nymphs suggests that paternal mitochondria proliferate as the eggs develop. Our data support recent theoretical predictions that paternal leakage may be more common than previously estimated.

ALLOCHTHONOUS SUBSIDY OF PERIODICAL CICADAS AFFECTS THE DYNAMICS AND STABILITY OF POND COMMUNITIES

Periodical cicadas emerge from below ground every 13 or 17 years in North American forests, with individual broods representing the synchronous movement of trillions of individuals across geographic regions. Due to predator satiation, most individuals escape predation, die, and become deposited as detritus. Some of this emergent biomass falls into woodland aquatic habitats (small streams and woodland ponds) and serves as a high-quality allochthonous detritus pulse in early summer. We present results of a two-part study in which we (1) quantified deposition of Brood X periodical cicada detritus into woodland ponds and low-order streams in southwestern Ohio, and (2) conducted an outdoor mesocosm experiment in which we examined the effects of deposition of different amounts of cicada detritus on food webs characteristic of forest ponds. In the mesocosm experiment, we manipulated the amount of cicada detritus input to examine if food web dynamics and stability varied with the magnitude of this allochthonous resource subsidy, as predicted by numerous theoretical models. Deposition data indicate that, during years of periodical cicada emergence, cicada carcasses can represent a sizable pulse of allochthonous detritus to forest aquatic ecosystems. In the mesocosm experiment, cicada carcass deposition rapidly affected food webs, leading to substantial increases in nutrients and organism biomass, with the magnitude of increase dependent upon the amount of cicada detritus. Deposition of cicada detritus impacted the stability of organism functional groups and populations by affecting the temporal variability and biomass minima. However, contrary to theory, stability measures were not consistently related to the size of the allochthonous pulse (i.e., the amount of cicada detritus). Our study underscores the need for theory to further explore consequences of pulsed allochthonous subsidies for food web stability.

Phylogenetics and phylogeography of the oak treehopper Platycotis vittata indicate three distinct North American lineages and a neotropical origin

Ecological differences including habitat, pollinators, and temporal separation between species and populations are important isolation barriers that can impede gene flows among evolving lineages, and subsequently lead to population divergence or speciation (Coyne and Orr, 2004). Temporal or allochronic speciation occurs when members of co-existing species or populations differ in breeding period that causes reproductive isolation as in the famous example of 13and 17-year periodical cicadas, Magicicada (Cooley et al., 2003). For insects like the apple maggot, Rhagoletis pomonella (Bush et al., 1989), the green lacewing, Chrysoperla plorabunda and C. downesi (Tauber and Tauber, 1977), and the treehopper, Enchenopa binotata (Wood, 1993a), the timing of reproduction can be greatly modified by their host-plant usage and the insect’s reproduction is strongly correlated with the plant phenology. Host shifting that changes life history timing thus plays an important role in reproductive isolation and speciation of phytophagous insects (Berlocher and Feder, 2002; Dres and Mallet, 2002). Treehoppers (Insecta: Hemiptera: Membracidae) are phytophagous insects that use their piercing and sucking mouthparts to feed on the phloem or xylem of plants (Wood, 1993b; Lin, 2006). The North American oak treehopper, Platycotis vittata (Fabricius) displays an extensive frontal horn dimorphism and color polymorphism in various life stages, between sexes, and throughout its geo-

Sex differences noted in mercury bioaccumulation in Magicicada cassini

This study focuses on quantitative differences in mercury bioaccumulation based on the sex of the specimen. The species of interest is an herbivorous, terrestrial insect. Male and female periodical cicadas (genus: Magicicada) analyzed using combustion atomic absorption spectrophotometry exhibit different levels of mercury bioaccumulation. The concentration of mercury in Magicicada cassini males was significantly higher than the concentration in females of the same species.