Acute resource pulses from periodical cicadas propagate to belowground food webs but do not affect tree performance

Abstract

Acute resource pulses can have dramatic legacies for organismal growth, but the legacy effects of resource pulses on broader aspects of community structure and ecosystem processes are less understood. Mass emergence of periodical cicadas (Magicicada spp.) provides an excellent opportunity to shed light on the influence of resource pulses on community and ecosystem dynamics: the adults emerge every 13 or 17 years in vast numbers over much of eastern North America, with a smaller but still significant number becoming incorporated into forest food webs. To study the potential effects of such arthropod resource pulse on primary production and belowground food webs, we added adult cicada bodies to the soil surface surrounding sycamore trees and assessed soil carbon and nitrogen concentrations, plant-available nutrients, abundance and community composition of soil fauna occupying various trophic levels, decomposition rate of plant litter after 50 and 100 days, and tree performance for 4 years. Contrary to previous studies, we did not find significant cicada effects on tree performance despite observing higher plant-available nutrient levels on cicada addition plots. Cicada addition did change the community composition of soil nematodes and increased the abundance of bacterial-and fungal-feeding nematodes, while plant feeders, omnivores, and predators were not influenced. Altogether, acute resource pulses from decomposing cicadas propagated belowground to soil microbial-feeding invertebrates and stimulated nutrient mineralization in the soil, but these effects did not transfer up to affect tree performance. We conclude that, despite their influence on soil food web and processes they carry out, even massive resource pulses from arthropods do not necessarily translate to NPP, supporting the view that ephemeral nutrient pulses can be attenuated relatively quickly despite being relatively large in magnitude.

The forest, the cicadas and the holey fluxes: Periodical cicada impacts on soil respiration depends on tree mycorrhizal type

“…2.5% across the landscape compared to years lacking cicada emergence events. Collectively, our results indicate that in addition to affecting tree hosts forest food webs and soil N cycling (Karban, 1980;Setälä et al, 2022;Williams & Simon, 2003), periodical cicadas affect ecosystem-scale processes by modifying the physical environment and by increasing the temperature sensitivity of microbial respiration. Thus, soil C models could be improved by accounting for emergence holes in regions with high emergence densities.…”

“…The emergence of periodical cicadas ( Magicicada septendecim, M. cassinii and M. septendeculain ) across the eastern United States every 13 or 17 years is a spectacular ecological phenomenon, with potentially important consequences for forest ecosystems. Cicada broods—which can number in billions of individuals—affect primary producers (Karban, 1980; Koenig & Liebhold, 2003; Yang & Karban, 2019), secondary consumers (Williams & Simon, 1995) and detritivores (Setälä et al., 2022; Yang, 2006) yet their role in modifying ecosystem and soil processes is largely unknown. Of the studies that have investigated cicada effects on soils, most have focused on the effects of decaying carcasses on nitrogen cycling (Menninger et al., 2008; Pray et al., 2009; Setälä et al., 2022; Wheeler, 1992; Yang, 2004; Yang & Karban, 2019).…”

“…Cicada broods—which can number in billions of individuals—affect primary producers (Karban, 1980; Koenig & Liebhold, 2003; Yang & Karban, 2019), secondary consumers (Williams & Simon, 1995) and detritivores (Setälä et al., 2022; Yang, 2006) yet their role in modifying ecosystem and soil processes is largely unknown. Of the studies that have investigated cicada effects on soils, most have focused on the effects of decaying carcasses on nitrogen cycling (Menninger et al., 2008; Pray et al., 2009; Setälä et al., 2022; Wheeler, 1992; Yang, 2004; Yang & Karban, 2019). This is not surprising as eastern forests are typically N‐limited (Davidson et al., 2004; LeBauer & Treseder, 2008) and cicadas possess exoskeletons made of N‐rich chitin.…”

Temporal variability in host availability alters the outcome of competition between two parasitoid species

“…Less extreme temporal variations in most abiotic and biotic resources are widespread (Mirth, Saunders & Amourda 2021), and are expected to have marked effects on consumer species. Generalist consumers, especially those that have long lifespans, can maintain whole-life fitness in the face of resource temporal variation through behavioral adaptations such as prey switching (Setälä et al, 2022). However, the performance of specialist consumers with low mobility and short lifespans may suffer considerably during short periods of low resources, even if longer-term total resource availability is unchanged (Yang et al, 2010).…”