Clones/genotypes
The degree of expression plasticity commonly varies between clones
(morphological defense, Havel 1985; Spitze 1992; Hammill et al. 2008;
Miyakawa et al. 2015; Boeing et al. 2006; Rabus et al. 2011; Weider
1985; Declerck and Weber 2003; Jeyasingh Weider 2005; Lively et al.
2000; Ferrari et al. 2001; WiÄ…ckowski et al. 2003; Dennis et al. 2011,
life-history traits De Meester 1993; Weider and Pijanowska 1993,
behavioral traits Michels et al. 2007). Interclonal variation in the
expression of inducible defenses in clones originating from habitats
with different predation regimes (Boersma et al. 1998; Boeing et al.
2006a; Dennis et al. 2010). The inter-clonal variations in the type and
degree of inducible defense of Daphnia hyalina result from
seasonal variations in the clonal composition of field populations
(Havel 1985; Stibor and Lampert 2000). Moreover, this might partly
account for the seasonally different occurrence of defended and
undefended morphs in the field, caused by changing predator regimes
(Havel 1985). The variation in degree of expression inducible defense is
predicted might be greater between species than between clones, although
no comparisons have been made. However clonal variations are not
negligible or small enough to be ignored. If the variation in the degree
of plasticity is greater for clonal variation than for interspecific
variation, then natural selection might be working strongly within the
species.