In the three-way analyses of the incidence of aestival diapause, all western populations combined, and two individual populations from the Sierra Nevada Range (AT, TP), showed significant photoperiod x family interactions in the incidence of aestival diapause, and both photoperiod and family had significant individual effects on the two populations from the Central Valley and foothill regions (DA, PL) (Table 2, Fig.
The two western populations from the Central Valley and foothill regions (DA and PL) had very low levels of aestival diapause whether aphids were present or not.
Visual assessment and three-way analyses indicated highly significant prey x family effects on the incidence of aestival diapause in three of these populations (SC, LS, and TP) (Table 2, Fig.
As aresutl, the phenotypic switch has a profound influence, not only on adult survivorship and the seasonal timing of reproduction or aestival dormancy, but also on voltinism and larval survivorship and development.
in the photoperiodic and prey components of the phenotypic switch that regulates aestival reproduction versus dormancy.
The expression of genetic variation in aestival diapause in all the Chrysoperla populations was highly dependent on photoperiod, and the very low incidence of reproductive diapause in all families subjected to an increase in daylength appears to eliminate family identity as a major source of variation in the reproductive activity of vernal adults (Fig.
In all of the populations we have studied including the ones here, prey presence influences the aestival phenotype only under constant long daylength -- not when the organisms experience an increase in daylength (see also Tauber and Tauber, 1986).
By modifying the effects of a relatively rigid, photoperiodically induced aestival reproductive dormancy, adult responsiveness to prey allows the insects to take advantage of locally or temporarily abundant prey.