Geographic patterns of herbivory and resource allocation to defense, growth, and reproduction in an invasive biennial, Alliaria petiolata

• Published in: Oecologia Vol. 148; no. 3; pp. 384 - 395
• Main Authors: Lewis, K.C, Bazzaz, F.A, Liao, Q, Orians, C.M
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01.06.2006; Springer Nature B.V
• Subjects: Alliaria petiolata; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Autoecology; Biological and medical sciences; Brassicaceae - metabolism; Brassicaceae - parasitology; Brassicaceae - physiology; defensive secretions; Ecological invasion; Ecophysiology; Ecosystem; environmental factors; Flowering; Flowering plants; Flowers; Flowers & plants; Fundamental and applied biological sciences. Psychology; geographical variation; Geography; Glucosinolates - biosynthesis; Herbivores; Hungary; Infestation; Invasive species; Leaves; Massachusetts; Plant biochemistry; plant damage; plant growth; plant reproduction; Plants; Plants and fungi; Population growth; Reproduction - physiology; resistance mechanisms; seasonal variation; sinigrin; weeds; Hungary; Massachusetts; Connecticut; USA, Massachusetts; USA, Connecticut; Europe; EICA; Herbivorous; Growth; Resource allocation; Herbivory; Invasive species; Reproduction; Phytophagous; Cruciferae; Animal plant relation; Dicotyledones; Angiospermae; Defense mechanism; Spermatophyta; Sinigrin; Alliaria petiolata; Interspecific relation
• ISSN: 0029-8549; 1432-1939
• DOI: 10.1007/s00442-006-0380-9

We investigated geographic patterns of herbivory and resource allocation to defense, growth, and reproduction in an invasive biennial, Alliaria petiolata, to test the hypothesis that escape from herbivory in invasive species permits enhanced growth and lower production of defensive chemicals. We quantified herbivore damage, concentrations of sinigrin, and growth and reproduction inside and outside herbivore exclusion treatments, in field populations in the native and invasive ranges. As predicted, unmanipulated plants in the native range (Hungary, Europe) experienced greater herbivore damage than plants in the introduced range (Massachusetts and Connecticut, USA), providing evidence for enemy release, particularly in the first year of growth. Nevertheless, European populations had consistently larger individuals than US populations (rosettes were, for example, eightfold larger) and also had greater reproductive output, but US plants produced larger seeds at a given plant height. Moreover, flowering plants showed significant differences in concentrations of sinigrin in the invasive versus native range, although the direction of the difference was variable, suggesting the influence of environmental effects. Overall, we observed less herbivory, but not increased growth or decreased defense in the invasive range. Geographical differences in performance and leaf chemistry appear to be due to variation in the environment, which could have masked evolved differences in allocation.