BioControl 49:245–260īoiteau G, Bousquet Y, Osborn WPL (1999) Vertical and temporal distribution of Coccinellidae (Coleoptera) in flight over an agricultural landscape. Environ Entomol 8:896–901īazzocchi GG, Lanzoni A, Accinelli G, Burgio G (2004) Overwintering, phenology and fecundity of Harmonia axyridis in comparison with native coccinellid species in Italy. Biol Invasions 6:463–471Īngalet GW, Tropp JM, Eggert AN (1979) Coccinella septempunctata in the United States: recolonization and notes on its ecology. Focusing on two formerly common native species, Adalia bipunctata and Coccinella novemnotata, we show they have become rare in their former ranges and discuss potential explanations for this phenomenon.Īlyokhin A, Sewell G (2004) Changes in a lady beetle community following the establishment of three alien species. For example, adventives have become the dominant species in a third of the assemblages where they are found. However, it is clear that specific systems and species have seen major shifts in recent years.
These results illustrate that even with multiple long-term data sets it is currently difficult to make any general conclusions regarding the impact adventive coccinellids have had on native coccinellid assemblages. Similarly, no significant difference was found in comparisons of diversity across all studies.
Seven long-term studies indicated that the total density of coccinellids increased by an average of 14% following establishment of adventive species, but this increase was not significant and in 4 of 7 cases the total density of coccinellids actually decreased following establishment. Reviewing published coccinellid surveys we found that the number of adventive species has increased steadily over the last century while the average proportion of native individuals has remained fairly constant until 1987 followed by a rapid decrease between 19.
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