The influence of damage level in Pinus sylvestris foliage on the performance of diprionid sawflies

Abstract

The influence of damage level in Pinus sylvestris foliage on the performance of diprionid sawflies. Accepted Oct. 2, 1991. Scand. J. For. Res. 7: 249-257, 1992 I tested the presence of rapid and delayed induced resistance in Pinus sylvestris L. by biotests, rearing three species of diprionid sawflies on defoliated and undefoliated trees. I damaged the pines artificially by cutting mature needles with scissors at the beginning of the growing season. Four levels of defoliation were created on the basis of levels of removed needle biomass. Sawfly larval and cocoon weights were retarded and relative growth rates delayed as a result of an increase in damage level. The larval periods were prolonged at most 2-6 days. The response to the damage was partly species-specific. The needle water content decreased in the following growing season in connection with low and moderate damage and increased at high damage levels. The nutrient contents of the foliage in the damaged and undamaged trees did not differ significantly. The Scots pine showed damage-induced changes in food quality after extensive defoliation, which affected, via plant, species using the same host.

Damage‐induced changes in woody plants and their effects on insect herbivore performance: a meta‐analysis

“…tort Gr Operophtera brumata P Neuvonen and Betula pubescens ssp. tort Gr, C Reich et al 1993 Pinus resinosa Ch Vanderklein and Reich 1999 Pinus resinosa Pho, Ch Honkanen and Haukioja 1994 Pinus syl6estris Gr, C, N, Wa Honkanen et al 1999 Pinus syl6estris Gr, Ch, N, Phe, Ter Lyytikäinen 1992a Pinus syl6estris N Lyytikäinen 1992a…”

Induced tree response to herbivory influences the foraging preference and performance of a conifer‐defoliating sawfly

“…Our study expands on past articles for sawflies, showing significant effects of previous herbivory on the suitability of branches for P. alaskensis . In contrast to diprionid sawflies, which generally have ameliorative or neutral effects on host quality (Niemelä et al., ; Lyytikäinen, ,b, ; McMillan & Wagner, ; Raffa et al., ), defoliation by P. alaskensis rendered black spruce branches less suitable. Pikonema alaskensis mothers laid nearly twice as many eggs in undefoliated vs. defoliated branches within the same crown.…”

“…Most studies to date have focused on diprionids (Diprionidae), all of which feed on coniferous trees (mainly of the genera Pinus , Abies , and Picea ), and a significant number of which have an unusually high outbreak tendency (Larsson et al., ; Price, ). In most cases, however, induced resistance is rare for conifer‐feeding diprionids, and most studies have reported neutral (Niemelä et al., ; Lyytikäinen, ,b, ) or even ameliorative effects of previous herbivory on sawfly preference (Krause & Raffa, ; Codella & Raffa, ; Trewhella et al., ) and performance (McMillan & Wagner, ; Raffa et al., ; but see Moreau & Quiring, ). This apparent lack of induced resistance may be partially because conifers store carbon resources – the basis of defensive allelochemicals – in their foliage, such that sawfly feeding may deprive the host of resources needed to assimilate defensive chemicals (Niemelä et al., ; Tuomi et al., ).…”

Sex-Specific Variations in Gypsy Moth Fitness, Immune Function, and Parasite Resistance Mediated by Background Defoliation of the Host Plant

“…According to the small values of differences between compared life history parameters (Figures 1(a) and 2(a)) of L. dispar as well as to data of mortality rate at rearing under laboratory conditions (Figure 3(a)), the strength of directly induced defense of trees is very weak. This might be explained by a positive correlation between the level of plant damage and the level of inducing of plant defense [16]. It seems that silver birch does not invest a lot of resources in the inducing of chemical defenses under a low level of defoliation by chewing insects.…”