The relative role of plasticity and demographic history in Capsella bursa-pastoris: a common garden experiment in Asia and Europe

Abstract

Background and aims The colonization success of a species depends on the interplay between its phenotypic plasticity, adaptive potential and demographic history. Assessing their relative contributions during the different phases of a species range expansion is challenging, and requires large-scale experiments. Here, we investigated the relative contributions of plasticity, performance and demographic history to the worldwide expansion of the shepherd’s purse, Capsella bursa-pastoris. Methods We installed two large common gardens of the shepherd’s purse, a young, self-fertilizing, allopolyploid weed with a worldwide distribution. One common garden was located in Europe, the other in Asia. We used accessions from three distinct genetic clusters (Middle East, Europe, and Asia) that reflect the demographic history of the species. Several life-history traits were measured. To explain the phenotypic variation between and within genetic clusters, we analysed the effects of (i) the genetic clusters, (ii) the phenotypic plasticity and its association to fitness, and (iii) the distance in terms of bioclimatic variables between the sampling site of an accession and the common garden, i.e., the environmental distance. Key results Our experiment showed that (i) the performance of C. bursa-pastoris is closely related to its high phenotypic plasticity; (ii) within a common garden, genetic cluster was a main determinant of phenotypic differences; and (iii) at the scale of the experiment, the effect of environmental distance to the common garden could not be distinguished from that of genetic clusters. Conclusion Phenotypic plasticity and demographic history both play important role at different stages of range expansion. The success of the worldwide expansion of C. bursa-pastoris was undoubtedly influenced by its strong phenotypic plasticity.

Competitive ability depends on mating system and ploidy level acrossCapsellaspecies

“…In contrast, within C. bursa-pastoris , the ranking among genetic clusters does not differ across experiments, where ASI populations, corresponding to the expansion front of the species ( Cornille et al , 2016 ), performed the worst and were the least competitive. This is in line with their higher genetic load ( Kryvokhyzha et al , 2019 ) and with the limited evidence of local adaptation at large geographical scale where ASI populations performed the worst under three different environments, including their native environment, in China ( Cornille et al , in press ).…”

Evaluating niche changes during invasion with seasonal models in Capsella bursa‐pastoris

“…Distinguishing between the relative importance of plasticity and adaptation for this success will require further study. Common garden experiments in C. bursa‐pastoris from the Eurasian range have shown that phenology is plastic for the species but it also has genetic variation across the range (Cornille et al, 2022). Experiments have shown that phenology shifts affect competition, potentially allowing C. bursa‐pastoris to persist in highly competitive environments (Orsucci et al, 2020).…”

“…As it colonized North America, it invaded both higher and lower latitudes than in its native range of Europe. C. bursa‐pastoris exhibits latitudinal and elevational clines in flowering time, and some populations are more responsive than others to environmental cues for flowering (Neuffer and Hoffrogge, 1999; Cornille et al, 2022). Additionally, Orsucci et al (2020) showed that C. bursa‐pastoris plants that flowered earlier than their counterparts were less affected by competition, potentially because the plants avoided interspecific competition.…”

Seasonal models reveal niche changes during invasion in Capsella bursa-pastoris

“…Our work showing shifts in the seasonal niche fit in with other work on phenology in C. bursa-pastoris. For example, common garden experiments in C. bursa-pastoris have shown 13 that phenology is plastic but also has genetic variation across the range (Cornille et al, 2022) and that phenology shifts affect competition, potentially allowing C. bursa-pastoris to persist in highly-competitive environments (Orsucci et al, 2020). Understanding the mechanism through which C. bursa-pastoris has managed to quickly expand its range could reveal broader patterns of evolution in invasive species, especially other polyploids and selfers.…”

“…As it colonized North America, it invaded both higher and lower latitudes than in its native range of Europe. C. bursa-pastoris exhibits latitudinal and elevational clines in flowering time, and some populations are more responsive than others to environmental cues for flowering (Neuffer and Hoffrogge, 1999; Cornille et al, 2022). Additionally, (Orsucci et al, 2020) showed that C. bursa-pastoris plants that flowered earlier than their counterparts were less affected by competition, potentially because the plants avoided interspecific competition.…”