Host plant effects on the genetic variation and correlations in the individual performance of the Gypsy Moth

Abstract

Summary1. Quantitative genetic analysis of variation in host-use ability was performed in an extremely polyphagous species -the Gypsy Moth. Various life-history traits were investigated by applying a split-family two-environment experimental design, where 30 full-sibling families were reared on oak and Locust Tree leaves. 2. Feeding on Locust Tree leaves decreased preadult viability, prolonged development time, decreased pupal mass both in males and females, and decreased reproductive effort in females. 3. The majority of broad-sense heritabilities did not change across host plants. 4. Significant expression of genetic variation in diet breadth was observed for development time and pupal mass both in males and females, but not for female reproductive effort traits. The heritabilities of plasticities were, on average, lower than heritabilities of the traits themselves. 5. The majority of genetic correlations between the host plants were significantly positive. The only trade-off was found between reciprocal value of reproductive index and the average mass of a fertilized egg within oak. This means that selection for the decrease in relative reproductive investment (under starvation during gradation) will be followed by laying larger eggs. Given that the Gypsy Moth has a cyclic population dynamics, this negative genetic correlation could have a role in maintaining genetic variability in this species.

Evolutionary Ecology of Egg Size and Number in a Seed Beetle: Genetic Trade-Off Differs Between Environments

“…In gypsy moths, the genetic correlation between pupal mass and an index of reproductive investment was positive only when larvae were reared on a marginally suitable host plant (locust tree), yet no correlation was detected when larvae were reared on a suitable host plant (oak; Lazarević et al 1998). In a more stressful environment, larger female gypsy moths have a higher tolerance to stress (measured as reproductive index) than smaller females.…”

“…Many optimality models predict that females should expend more reproductive effort in oviposition sites of high quality compared to sites of low quality (e.g., Parker and Courtney 1984;Charnov and Skinner 1985). Among other traits, environmental differences in genetic (co)variances or genetic correlations have been detected (e.g., Via 1984;Service and Rose 1985;Scheiner et al 1989;Holloway et al 1990;Guntrip et al 1997;Lazarević et al 1998;Gu and Danthanarayana 2000;Bégin and Roff 2001), yet we lack research examining how evolutionary relationships among offspring size, number, and traits affecting total reproductive effort may differ among environments.Here, we examine the genetic relationships among egg size, lifetime fecundity, and female body mass (a trait that affects total reproductive effort) in a seed beetle, Stator limbatus, that oviposits and develops within seeds of leguminous plants. These relationships were examined on two host-plant species (environments), Acacia greggii and Cercidium floridum, because S. limbatus exhibits very different reproductive strategies on seeds of these two species; females lay larger but fewer eggs on C. floridum seeds than on A. greggii seeds.…”

“…Many optimality models predict that females should expend more reproductive effort in oviposition sites of high quality compared to sites of low quality (e.g., Parker and Courtney 1984;Charnov and Skinner 1985). Among other traits, environmental differences in genetic (co)variances or genetic correlations have been detected (e.g., Via 1984;Service and Rose 1985;Scheiner et al 1989;Holloway et al 1990;Guntrip et al 1997;Lazarević et al 1998;Gu and Danthanarayana 2000;Bégin and Roff 2001), yet we lack research examining how evolutionary relationships among offspring size, number, and traits affecting total reproductive effort may differ among environments.…”

Plant-Toxin Interactions in Transgenic Bt Cotton and their Effect on Mortality of <I>Helicoverpa armigera</I> (Lepidoptera: Noctuidae)

“…It is estimated that worldwide at least 500 plants are hosts to L. dispar, predominantly poplar, oak and birch (Lazareviae et al 1998). Therefore, L. dispar was selected to quantify the insecticidal effect of transgenic poplar with the fusion protein gene of the spider insecticidal peptide and Bttoxin C-peptide in controlled laboratory experiments.…”

Quantitative genetics of preference and performance on chickpeas in the noctuid moth, Helicoverpa armigera

“…First, is there additive genetic variation in the insect population for the ability to utilise the resistant host genotype? A number of studies have estimated levels of additive genetic variation in host use in herbivorous insects, the majority of which consider variation in the ability of a generalist herbivore to feed on different host species (Via, 1984a, b;Ward et al, 1993;Carriere and Roitberg, 1994;Fox and Caldwell, 1994;Hawthorne and Via, 1994;Sheck and Gould, 1996;Thompson, 1996;Tucic et al, 1997;Ueno et al, 1997;Bossart, 1998;Hawthorne, 1998;Lazarevic et al, 1998;Gu et al, 2001;Poore and Steinberg, 2001).…”