Open access publications in the SLU publication database

Abstract

The pine weevil (Hylobius abietis (L.); Coleoptera: Curculionidae) has a high economic impact on forest regeneration in Europe. The general biology of the pine weevil has received considerable attention, but there is insufficient knowledge about its diel behaviour and time budget. Therefore, the feeding and locomotion behaviour of individual adult weevils on Norway spruce (Picea abies (L.) Karst.) seedlings is observed for 24 hour-periods in the laboratory. Both girdled and non-girdled seedlings are used to assess how the weevils’ behaviour is influenced by the plants physiological response to the girdling. The locomotion pattern shows a distinct maximum during the beginning of the dark phase whereas most feeding occurs during the second half of the dark phase and the first hours of the subsequent light phase. The girdling treatment increase the time that weevils spend on the seedlings during the first part of an observation session, but has no effect on their feeding pattern. The weevils’ time budgets on girdled and non-girdled seedlings are similar. On average, they spend 34 % of their time in locomotion and 6 % on feeding. Females spend more time feeding than males (7.1 % vs. 4.2 %), possibly because they have higher food requirements, e.g. for egg production. Females also spend more time in total on the seedlings than males (26.3 % vs. 7.0 %). This study reveals, in high temporal resolution, the diel feeding and locomotion behaviour and time budget of male and female pine weevils.