Abstract:  To explore the potential factors that influence host plant selection of Ophraella communa for oviposition on common ragweed (Ambrosia artemisiifolia), a consecutive field survey of 60 plant patches for egg deposition was made in the field.  Hurdle models were fitted to analyze factors that influence probability of oviposition and the amount of eggs deposited on plants. The results showed that: (1) Oviposition increased with progress of the season, feeding damage level, plant height, and patch size in open environment, but decreased with plant patch size, blossom, seasonal progress in blossom, and feeding damage level with progress of the season and after blossom. (2) Number of eggs deposited on plants increased with progress of the season, feeding damage level, open environment, feeding damage level at the blossom stage, and plant height at the blossom stage, but decreased with blossom, and feeding damage level with progress of the season. (3) The increase of eggs on plants with progress of the season was more distinct during vegetative growth stage than blossom stage, and constantly linear in open environment, but linear at first and then asymptotic in shading environment. The study suggests that the factors influencing oviposition selection are not identical to those affecting quantity of egg deposition, and the influence is exercised more through interactions between factors than single factor alone.  

Key words:  Ophraella communa, oviposition selection, Ambrosia artemisiifolia, environmental factors, hurdle model, invasion biology