Clonal variation in foliar chemistry of aspen: effects on gypsy moths and forest tent caterpillars

Abstract

Quaking aspen (Populus tremuloides) exhibits striking intraspecific variation in concentrations of phenolic glycosides, compounds that play important roles in mediating interactions with herbivorous insects. This research was conducted to assess the contribution of genetic variation to overall phenotypic variation in aspen chemistry and interactions with gypsy moths (Lymantria dispar) and forest tent caterpillars (Malacosoma disstria). Thirteen aspen clones were propagated from field-collected root material. Insect performance assays, measuring survival, development, growth, and food utilization indices, were conducted with second and/or fourth instars. Leaf samples were assayed for water, nitrogen, total nonstructural carbohydrates, condensed tannins, and phenolic glycosides. Results showed substantial among-clone variation in the performance of both insect species. Chemical analyses revealed significant among-clone variation in all foliar constituents and that variation in allelochemical contents differed more than variation in primary metabolites. Regression analyses indicated that phenolic glycosides were the dominant factor responsible for among-clone variation in insect performance. We also found significant genetic trade-offs between growth and defense among aspen clones. Our results suggest that genetic factors are likely responsible for much of the tremendous phenotypic variation in secondary chemistry exhibited by aspen, and that the genetic structure of aspen populations may play important roles in the evolution of interactions with phytophagous insects.

Invasive Spiraea tomentosa: a new host for monophagous Earias clorana?

“…The leaves of Spiraea tomentosa offer larval E. clorana phagostimulants, like sugars (Harborne 1993;Levesque et al 2002), the concentrations of which are greater in Spiraea tomentosa leaves than in those of Salix viminalis. Their higher levels usually result in a shorter duration of larval development and pupal period, as well as greater body mass (Hwang and Lindroth 1997;Kaitaniemi et al 1998;Łukowski et al 2015). In the case of larvae fed with Spiraea tomentosa leaves, however, we did not find this relationship (Table 1).…”

Larval nutrition affects life history traits in a capital breeding moth

“…The protein:carbohydrate ratio of aspen foliage is variable but tends to fluctuate within the range encompassed by our artificial diets (Hwang and Lindroth, 1997), and the high performance we observed on foliage is more likely to be linked to other factors such as micronutrients, moisture, mechanical properties or secondary chemistry. However, general conclusions about natural and artificial foods cannot be drawn from these results because other types of The estimated marginal mean from the MANCOVA is the mean corrected for the effect of the covariate and shows differences between diets for individuals with the same value of the covariate (total moth mass=73.9 mg).…”

Age-Related Shifts in Leaf Chemistry of Clonal Aspen (Populus tremuloides)

“…Quadratic regression provided the best fit (P < 0.001) variation may be due to genetics rather than to environment. However, phenolic glycosides (the most variable compounds) show relatively little phenotypic plasticity in common gardens (Hwang and Lindroth, 1997;Osier and Lindroth, 2001). Thus, most of the observed variation in concentration among clones may be due to genotype.…”