Investigating preference-performance relationships in aboveground-belowground life cycles: a laboratory and field study with the vine weevil (Otiorhynchus sulcatus)

Abstract
To date, the preference-performance hypothesis has principally considered insect herbivores with aboveground life cycles, although the hypothesis could be equally relevant to insects with life stages occurring both aboveground and belowground. Moreover, most studies to date have focussed on either laboratory or field experiments, with little attempt made to relate the two. In this study, the preference-performance hypothesis was examined in an aboveground-belowground context using the vine weevil (Otiorhynchus sulcatus F.) (Coleoptera: Curculionidae) and two cultivars of the host plant red raspberry (Rubus idaeus), Glen Rosa and Glen Ample. A two-year field study (2008-2009) was also undertaken to characterise the population dynamics of adult vine weevils on the two raspberry cultivars. Vine weevil larval performance (abundance and mass) differed significantly between Glen Rosa and Glen Ample, with Glen Rosa resulting in 26% larger but 56% fewer larvae compared to Glen Ample. Larval abundances were significantly and positively correlated with root nitrogen and magnesium concentrations, but negatively correlated with root iron concentrations. The two cultivars were not significantly different in concentrations of these minerals however. Adult weevils did not preferentially select either of the two cultivars for egg laying (laying 3.08 and 2.80 eggs per day on Glen Ample and Glen Rosa respectively) suggesting that there was no strong preference-performance relationship between adult vine weevils and their belowground offspring. Whilst larval development in laboratory experiments showed significant differences between the two raspberry cultivars, populations of adult vine weevils were similar on both cultivars in 2008 and 2009. Our results highlight that performance differences detected in controlled experiments may not necessarily result in significant differences at a population level in the field.
Year
2012
Category
Refereed journal
Output Tags
SG 2006-2011 WP 1.3 Soft Fruit Genetics and Pathology