Host-plant preference and performance of the vine weevil Otiorhynchus sulcatus

The relationship between reproductive performance and preference for potential
host plants of the vine weevil is investigated, as shown in tests on contact
(or feeding) preference, presented herein, and tests on olfactory preference,
published elsewhere.
Assessment of reproductive performance shows that the host-plant range of the
adult vine weevil Otiorhynchus sulcatus in Europe is limited to one gymnosperm
genus (Taxus sp.) and a broad range of angiosperm plants in two subclasses of
the Dicotyledonae, namely Dilleniidae and Rosidae. The successful reproduction
on very distantly related plant taxa suggests that the original weevil- and
plant-habitat has mediated the current host-plant range of the vine weevil.
Contact-preference tests with equally suitable hosts, such as Aronia, Fragaria,
Euonymus and Taxus, and one less suitable host, Humulus, indicate a mismatch
between contact preference and performance and, as far as olfactory preferences
are known, these match neither the contact preferences nor the performance.
This mismatch may arise because (i) host plant species offered do not
occur in weevil habitat in Europe (e.g. Aronia and the cultivated Fragaria come
from North America) and (ii) predation (or disease) risks differ among host
plants, thereby altering effective reproductive performance.
With respect to performance on novel hosts (Thuja, Prunus) and bad hosts
(Rhododendron), some between-individual variation is found within a single
population, suggesting that local populations harbour (possibly genetic)
variation for adaptation to new hosts. How this variation is maintained in the
face of strong selection pressures on local populations of flightless and
thelytokous weevils, is an important question for understanding the broad
host plant range in the vine weevil.