Transient synchrony among populations of five foliage‐feeding Lepidoptera

Abstract

Studies of transient population dynamics have largely focused on temporal changes in dynamical behaviour, such as the transition between periods of stability and instability. This study explores a related dynamic pattern, namely transient synchrony during a 49-year period among populations of five sympatric species of forest insects that share host tree resources. The long time series allows a more comprehensive exploration of transient synchrony patterns than most previous studies. Considerable variation existed in the dynamics of individual species, ranging from periodic to aperiodic. We used time-averaged methods to investigate long-term patterns of synchrony and time-localized methods to detect transient synchrony. We investigated transient patterns of synchrony between species and related these to the species' varying density dependence structures; even species with very different density dependence exhibited at least temporary periods of synchrony. Observed periods of interspecific synchrony may arise from interactions with host trees (e.g., induced host defences), interactions with shared natural enemies or shared impacts of environmental stochasticity. The transient nature of synchrony observed here raises questions both about the identity of synchronizing mechanisms and how these mechanisms interact with the endogenous dynamics of each species. We conclude that these patterns are the result of interspecific interactions that act only temporarily to synchronize populations, after which differences in the endogenous population dynamics among the species acts to desynchronize their dynamics.

Temporal patterns of dispersal-induced synchronization in population dynamics

“…Finally, we would like to put our observations in the context of the studies of transient dynamics in ecology, which appears to be very important and quite common (Hastings et al, 2018) including population synchronization phenomena (Klapwijk et al, 2018). From a mathematical perspective, the idea that the ecologically relevant dynamics is not necessarily the dynamics near and on the attracting synchronization manifold in the phase space is somewhat similar to the idea of importance of transients in ecology.…”

Weather and regional crop composition variation drive spatial synchrony of lepidopteran agricultural pests

“…Beet armyworm and fall armyworm showed strong synchrony at nearly all times and timescales, whereas for hornworm the predominant pattern was asynchrony, with synchrony occurring only episodically at certain timescales. Such a pattern may be consistent with the occurrence of occasional synchronising events on a background of asynchrony (Klapwijk et al ., ). Some species showed synchrony that appeared to change its dominant period over time, such as cabbage looper, for which synchrony shifted from c .…”

Outbreaking forest insect drives phase synchrony among sympatric folivores: Exploring potential mechanisms

“…Similarly, there is evidence that the numerical response of shared predators can synchronize prey herbivore populations (Marcström et al, 1988). Finally, Baltensweiler (1991) and Klapwijk et al (2018) suggested that forest folivore populations may be synchronized when one species reaches outbreak levels causing a reduction in either quantity or quality of a shared foliar resource.…”

“…One group of consumer species for which interspecific synchrony is known to commonly occur is in foliage-feeding forest insects (Kawatsu, Yamanaka, Patoèka, & Liebhold, 2019;Klapwijk et al, 2018;Miller & Epstein, 1986;Myers, 1998;Raimondo, Liebhold, Strazanac, & Butler, 2004;Raimondo, Turcáni, Patoèka, & Liebhold, 2004). Several explanations have been proposed to explain synchrony among these folivore populations.…”

“…Shared influences of interannual variability in weather is one of these proposed mechanisms (Miller & Epstein, 1986;Myers, 1998). Others have suggested synchronization via shared trophic interactions, such as predators and parasitoids (Marcström, Kenward, & Engren, 1988;Raimondo, Turcáni, et al, 2004) or shared host plants (Baltensweiler, 1991;Klapwijk et al, 2018).…”