Phenological synchrony between a butterfly and its host plants: Experimental test of effects of spring temperature

Abstract

Abstract1. Climate-driven changes in the relative phenologies of interacting species may potentially alter the outcome of species interactions.2. Phenotypic plasticity is expected to be important for short-term response to new climate conditions, and differences between species in plasticity are likely to influence their temporal overlap and interaction patterns. As reaction norms of interacting species may be locally adapted, any such climate-induced change in interaction patterns may vary among localities. However, consequences of spatial variation in plastic responses for species interactions are understudied.3. We experimentally explored how temperature affected synchrony between spring emergence of a butterfly, Anthocharis cardamines, and onset of flowering of five of its host plant species across a latitudinal gradient. We also studied potential effects on synchrony if climate-driven northward expansions would be faster in the butterflies than in host plants. Lastly, to assess how changes in synchrony influence host use we carried out an experiment to examine the importance of the developmental stage of plant reproductive structures for butterfly oviposition preference.4. In southern locations, the butterflies were well-synchronized with the majority of their local host plant species across temperatures, suggesting that thermal plasticity in butterfly development matches oviposition to host plant development and that thermal reaction norms of insects and plants result in similar advancement of spring phenology in response to warming. In the most northern region, however, relative phenology between the butterfly and two of its host plant species changed with increased temperature. We also show that the developmental stage of plants was important for egg-laying, and conclude that temperature-induced changes in synchrony in the northernmost region are likely to lead to shifts in host use in A. cardamines if spring temperatures become warmer. Northern expansion of butterfly populations might possibly have a positive effect on keeping up with host plant phenology with more northern host plant populations.5. Considering that the majority of insect herbivores exploit multiple plant species differing in their phenological response to spring temperatures, temperature-induced changes in synchrony might lead to shifts in host use and changes in species interactions in many temperate communities.

Spring- and fall-flowering species show diverging phenological responses to climate in the Southeast USA

“…Changes in the timing of species' life history events-Bphenological shifts^-are closely linked to changes in climate and can produce cascading effects across ecosystems, altering ecosystem functioning (Parmesan 2006;Calinger et al 2013), productivity (Richardson et al 2010), and ecological interactions such as those between plants and pollinators (Kharouba and Vellend 2015;Forrest 2015) or plants and migratory birds (Both et al 2006). Despite myriad studies since the turn of the century investigating the effects of climate change on plant phenology (i.e., Bphenological sensitivity^) using observational data (e.g., Fitter and Fitter 2002;Ellwood et al 2014;Tansey et al 2017), herbarium specimens (e.g., Primack et al 2004;Lavoie and Lachance 2006;Munson and Long 2016), experiments (e.g., Price and Waser 1998;Pan et al 2017;Posledovich et al 2017), and combinations of data sources (e.g., Miller-Rushing et al 2006;Panchen et al 2012), significant gaps in our understanding of these phenomena and their potential consequences remain (Willis et al 2017). Notably, the phenological sensitivity of plants to climate change in warm, humid temperate to subtropical regions, as well as the effects of climate change on autumn phenology, remain poorly understood (Pau et al 2011;Willis et al 2017; but see Von Holle et al 2010;Park and Schwartz 2015;Gallinat et al 2015).…”

Butterfly–host plant synchrony determines patterns of host use across years and regions

“…An index value of 0 thus means that the inflorescence had only buds and was in the earliest developmental stage at the time of recording (corresponding to a late phenology relative to the flight of A. cardamines), while a value of one means that the inflorescence had only pods and was in the latest developmental stage (corresponding to an early phenology relative to the flight of A. cardamines). Second, the preferred development stage for oviposition by A. cardamines, was assessed using data from a previous preference experiment (Posledovich et al 2018). In this experiment, naïve A. cardamines were simultaneously exposed to all host plants (A. thaliana, A. glabra, A. hirsuta, C. bursa-pastoris and C. pratensis) at different development stages ranging from only buds to at least one seedpod in a series of trials in enclosures (3 × 3 × 2.5 m) with artificial green grass and lighting which replicated natural sunlight (Posledovich et al 2018).…”

“…Second, the preferred development stage for oviposition by A. cardamines, was assessed using data from a previous preference experiment (Posledovich et al 2018). In this experiment, naïve A. cardamines were simultaneously exposed to all host plants (A. thaliana, A. glabra, A. hirsuta, C. bursa-pastoris and C. pratensis) at different development stages ranging from only buds to at least one seedpod in a series of trials in enclosures (3 × 3 × 2.5 m) with artificial green grass and lighting which replicated natural sunlight (Posledovich et al 2018). All oviposition events were recorded during 1.5 h from the start of egg-laying and the preferred development stage was calculated as the mean development index of the very first plant chosen for oviposition in each trial (639 plants were tested whereof 34 received the first egg across the trials).…”

Geographic variation in the intensity of warming and phenological mismatch between Arctic shorebirds and invertebrates

“…, Posledovich et al. ) and examined the relationship between the extent of climate change and the extent of mismatch that we estimated using three years of observational data as a snapshot at each of 10 sites. In the second part of our study, we examined latitudinal and longitudinal gradients in contemporary climatic conditions, as well as their relationship with the phenology of two trophic levels (Fig.…”

“…Given the rarity of long-term, multi-trophic-level data in the North American Arctic, we examined the extent of phenological mismatches between six shorebird species and their invertebrate prey at 10 sites spread across the Arctic over the course of three years. The first part of our study employed a "space-for-time substitution" approach (Pickett 1989, Blois et al 2013, Posledovich et al 2018 and examined the relationship between the extent of climate change and the extent of mismatch that we estimated using three years of observational data as a snapshot at each of 10 sites. In the second part of our study, we examined latitudinal and longitudinal gradients in contemporary climatic conditions, as well as their relationship with the phenology of two trophic levels (Fig.…”