Herbivory by sucking mirid bugs can reduce nectar production in Asphodelus aestivus Brot.

Abstract

This experimental study focused on the effects of a mirid bug herbivore, Capsodes infuscatus on the flower nectar yield of a Mediterranean geophyte, Asphodelus aestivus. The effects of increasing densities of adult C. infuscatus bugs on A. aestivus, on the nectar volume and concentration were examined. Significant decreases were found in the number of flowers and nectar production as C. infuscatus densities increased. Analysis of covariance (ANCOVA) showed that nectar production was not affected by environmental variables (air temperature, relative air humidity and day-time) that were treated as covariates for the various bug herbivory intensities. Sugar concentration did not vary significantly among treatments, indicating that abiotic conditions were not responsible for differing nectar amounts. In light of A. aestivus’s dependence on pollinator visits to produce seeds, we conclude that C. infuscatus could impair pollination success by reducing the amount of nectar in flowers. To the best of our knowledge, the present study is the first to show that insect herbivores do not necessarily have to remove segments from the flower in order to decrease nectar secretion.