Oikos (2004) 105, 368-376
J. Gross, N. E. Fatouros, M. Hilker (2004)
The significance of bottom-up effects for host plant specialization in "Chrysomela" leaf beetles
Oikos 105, 368-376
Abstract: The leaf beetle species Chrysomela lapponica, which belongs to the so-called C.
interrupta group, forms distinct allopatric populations either on willows (Salicaceae) or birches (Betulaceae). It was recently suggested that, on several occasions, host plant shifts from Salicaceae to Betulaceae occurred independently within the C. interrupta group. Our study aims to elucidate bottom-up effects of the host plants that might have shaped the evolution of host plant specialization in the populations of C. lapponica, and thus, to shed some light on the driving forces of host shifts within the C. interrupta
group, too. We compared the oviposition behaviour and performance of two C.
lapponica populations, one of which has adapted to birches and the other to willows. The studies were conducted under laboratory conditions, eliminating the impact of natural enemies. Experiments involving the transfer of individuals of the birchspecialized population to willows and vice versa with individuals of the willowspecialized population to birches aimed to examine the plasticity in host plant use. Females of each population almost exclusively chose their natural host plant for oviposition, when offering birch and willow in dual choice experiments. When specimens of the two C. lapponica populations were reared on their natural host plants, the birch specialists suffered higher mortality, needed a longer period of development and produced less larval defensive secretion than the willow specialists. When the birch specialists were fed with willow, these performance parameters decreased even more. Other parameters, such as body weight and fecundity, did not differ between birch and willow specialists when they were fed with their natural host plant. While individuals of the birch-specialized population could be reared on willow,
all neonate larvae from the willow-specialized population died after being transferred to birch. The significance of these bottom-up effects for the evolution of host plant specialization in C. lapponica is discussed.
(The abstract has been supplied by the author or ISPI and is excluded from the Creative Commons licence.)
Database assignments for author(s): Jürgen Gross, Monika Hilker
Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
population dynamics/ epidemiology
Pest and/or beneficial records:
| Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
|---|---|---|---|---|
| Chrysomela lapponica | Willow (Salix) | Finland | ||
| Chrysomela lapponica | Birch (Betula) | Czech Republic |
