Phenotypic integration
In spite of the recognized importance that changes in the correlation
structure can have for evolutionary change
(Lande & Arnold, 1983), we still know
surprisingly little about how the environment influences levels of
phenotypic integration. Despite much recent progress on this topic
(Pigliucci & Preston, 2004;
Schlosser & Wagner, 2004), most
empirical studies have only studied patterns of phenotypic integration
in a single environment (Pigliucci &
Preston, 2004; but see Liu et al., 2007;
Pigliucci et al. , 1995). In this
study, we found an increase in coefficient of integration (CI) with
density at 50 d (Gianoli, 2004;
Schlichting, 1986;
Wylde & Bonduriansky, 2020), and
decrease in the number of correlations (NC) with density at 70 d
(Badyaev et al. , 2005;
Mallitt et al. , 2010;
Pigliucci & Kolodynska, 2002). The
stage-dependence responses in CI suggested the strength of response of
integration to density decreased over time. It is hypothesized that the
increase in the number and strength of correlations among functionally
correlated traits (phenotypic integration) is related to the extent of
environmental stress (Gianoli, 2004;
Schlichting, 1986), and endow plants the
ability to effectively respond to such stress
(Chapin III, 1991). At 70 d, density
effects on plants became attenuated, due to small individuals being
obsoleted (Wang et al. , 2017).
This may lead to weakened responses in trait correlations. It is
reported phenotypic integration contributed to differences between
native and invasive species less than phenotypic plasticity
(Osunkoya et al. , 2014), but
differences in phenotypic integration plasticity were more
distinguishable than differences in plasticity for clones ofDaPhnia magna (Plaistow & Collin,
2014). It suggested phenotypic integration plays a more important role
in plant adaptation to environmental stresses.