Wj. Dekogel et al., OVIPOSITION PREFERENCE OF WESTERN FLOWER THRIPS FOR CUCUMBER LEAVES FROM DIFFERENT POSITIONS ALONG THE PLANT STEM, Entomologia experimentalis et applicata, 82(3), 1997, pp. 283-288
While the distribution of herbivorous insects over leaves along the st
em often shows a peak at some distance from the apex this does not nec
essarily reflect an innate preference as alternative explanations can
be provided such as impact of predators and inter- or intraspecific co
mpetitors. It is of interest to determine which factors shape the dist
ribution of insects over the leaves of a plant. Do leaves from differe
nt positions differ in suitability for insects and is that reflected i
n the insect's preference, or are other factors involved? In this pape
r we assess how the herbivorous insect western flower thrips, Franklin
iella occidentalis (Pergande) (Thysanoptera: Thripidae), chooses among
leaves from different positions relative to the apex of cucumber, Cuc
umis sativus (L.) plants. On leaf discs of a susceptible and three par
tially resistant cucumber accessions, thrips reproduction was highest
on apical leaves and lowest on basal leaves. In dual-choice essays thr
ips females preferred younger leaves over older leaves for oviposition
in all cucumber accessions tested, as was predicted from the no-choic
e assay. This indicates that differences in leaf suitability are an im
portant factor in determining thrips distribution on cucumber plants.