Preference and Performance of the Pine-Tree Lappet Dendrolimus pini on Various Pine Species

Adrian Łukowski,Piotr Karolewski,Dawid Adamczyk,Marian J Giertych,Ewa Mąderek

doi:10.3390/f12091261

Abstract

Global commercial and recreational transport may lead to the unintentional invasion of insect species, which in turn may pose a threat to native organisms. In this study, we aimed to assess whether the economically important pest of Pinus sylvestris L., moth Dendrolimus pini L. (DP), is able to feed on nine other pine species, and how this will affect its survival, performance, growth, and development. We carried out food choice tests and a no-choice laboratory feeding experiment. We found that this insect mostly preferred its prime host, but also Pinus cembra L., Pinus contorta Douglas ex Loudon, Pinus nigra J.F.Arnold, and Pinus ponderosa Douglas ex C.Lawson. The performance test revealed a host-specific response of DP to the host plant. This response was manifested in a large variation in body mass as well as in a decrease or increase in life-history traits, such as fecundity, and wing morphology parameters. However, the larvae’s choice of particular hosts corresponded to the results of the performance test. Larvae more willingly selected food allowing better results in their performance. Larvae achieved better values of growth and development when fed on European and North American pine species or on species with two- and three-needle fascicles. In addition, attractants and repellents in needles of different pine species were chemically analyzed. Variations in the secondary metabolite composition as well as the specific leaf area of different pine species effectively explained the results found in the insects, but the content of sugars and nitrogen remains to be elucidated. We speculate that DP poses a serious threat to large areas of pine forests, if transferred, as it can survive and develop on many economically important tree species in North America and Europe.

Highlights

Herbivores use various parts of host plants to obtain the required nutrients for development and reproduction [1,2,3]
The results of χ2 tests in the multi-choice experiment, where each larva had the opportunity to choose from 10 different host plants, indicate that that the estimated probability differs significantly from the hypothesized values in some plant species treatments (χ2 = 94.2727; p < 0.0001; Figure 1)
We found an influence of pine origin on the content of substances that were favorable for insect development, the plant defense compound content (TPh, tannins, terpenoid content (TT)), as well as specific leaf area (SLA) values, which can represent the general mechanical defense of needles (Table 3 and Figure 7)

Summary

Introduction

Herbivores use various parts of host plants to obtain the required nutrients for development and reproduction [1,2,3]. Plants improve their defense strategies to counteract feeding, especially by enhancement of the leaf chemical defense [4,5,6,7]. Ingesting high-quality food improves larval performance [11] and, as a consequence, enhances survival [12,13] and adult specimen reproduction [8,14,15]. A good prediction model of the potential distribution should take into account potential host plants, the inclusion of which should be preceded by the examination of the possibility of accepting such hosts [31,32]

Objectives

Methods

Results

Discussion

Conclusion