We examined emergence of male and female 13-yr periodical cicadas (Brood XIX) and mortality, due to avian 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/m 2 , 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 that 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.

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Continuous trapping on the bark surface of Dendroctonus brevicomis LeConte infested trees in the central Sierra Nevada mountains was undertaken with the objective of determining the spatial and temporal arrival patterns of the natural enemies and other insect associates of the western pine beetle. Over 100 species of D. brevicomis associates were collected and patterns of arrival were described for many of these. The main bark beetle predators were trapped during D. brevicomis mass arrival and shortly thereafter. Enoclerus lecontei, Temnochila chlorodia, and Aulonium longum, all predaceous beetles on D. brevicomis adults and larvae, were among the first species to arrive, as was Medetera aldrichii (Diptera), a larval predator. The bark beetle parasites Roptrocerus xylophagorum and Dinotiscus (=Cecidostiba) burkei (Hymenoptera) were well synchronized with the beetles’ life cycle as they arrived late in the beetles’ larval stages when suitable hosts were available.Approximately twice as many associates were trapped in the first (spring) beetle generation as in the second (fall). Differences between species with regard to height distribution were common, and these often varied with seasonal beetle generation.Calculations of changes in species diversity through time, of the associate complex trapped at the bark surface, were made for both the first and second beetle generation. Linear correlation analysis indicated a highly significant increase in species diversity occurred from the time of the beetles’ mass arrival until brood emergence. This increase may correspond to an increase in diversity of the structure of the subcortical community, as more insect species arrived and progressively modified the habitat of the newly killed tree.