Adult Feeding Preference and Fecundity in the Large Pine Weevil, Hylobius abietis (Coleoptera: Curculionidae)

SIMPLE SUMMARY: The large pine weevil, Hylobius abietis, is a weevil species that causes extensive damage to coniferous seedlings in Eurasia. Its importance in central Europe has recently increased due to sanitation logging and reforestation activities in the areas of recent bark beetle outbreak. H. abietis is a polyphagous species and host plants on which pine weevils develop and feed are important determinants of their fecundity and reproductive success. In this study, we tested adult feeding preferences of H. abietis in outdoor conditions, and we studied the influence of food source on fecundity. Seedlings of Pseudotsuga menziesii were the most preferred, but low oviposition indicated lack of nutrients. Feeding on Betula pendula was recorded only in one group of seedlings, and high mortality of weevils was observed. Knowledge of food preferences together with fecundity on alternative food sources may contribute to planning appropriate protective measures and forecasting the damage in areas where former spruce monocultures are being converted to mixed-species stands. Mixed-species plantations could also represent an alternative to insecticidal protection of coniferous seedlings. ABSTRACT: Adult feeding preferences of Hylobius abietis on Picea abies, Larix decidua, Pinus sylvestris, Pseudotsuga menziesii, Abies alba and Betula pendula were tested in outdoor conditions. The preferred food source was P. menziesii, and the mean bark area consumed per seedling was 440.8 ± 147.9 mm(2). The second most preferred host was P. abies. The coniferous species that suffered the least damage was A. alba (76.8 ± 62.56 mm(2) per seedling). B. pendula was the least preferred source of food, and it caused mortality of 60% of weevils that fed on it. Weevils exhibited large differences in fecundity when fed with different tree species in a laboratory experiment. The largest number of eggs was laid by females fed with P. abies. Mean egg numbers reached 26.4 ± 24.89 eggs per experiment for P. abies. Similar fecundity was observed in weevils fed with twigs of P. sylvestris. Oviposition was approximately six times lower in females fed with L. decidua and P. menziesii. The maximum number of eggs laid by a single female during a one-month experiment was 90. The results are discussed in relation to management of H. abietis.