Abundance, migration and distribution of Coccinella septempunctata (Coleoptera: Coccinellidae) in a highly biodiverse urban garden.

Within agroecosystems, the presence along the year of ladybirds is a crucial factor for aphids biological control. In the urban environment, this becomes exacerbated due to stricter regulations against use of pesticides. The demonstrative garden of the agricultural faculty of Bologna University is located in the urban environment, and consists in about 0.3 ha composed by more than 400 plots. The garden hosts more than 350 plant species, including forage, industrial, and horticultural crops, herbs and cereals. In order to assess the presence and preferred hosts of aphidifagous ladybirds within the demonstrative garden, weekly visual samplings in each of the 400 plots were conducted between March and September 2015. This included monitoring of presence and abundance of Coccinella septempunctata (the most important native and wild lady beetle species in Italy). Adult ladybirds were observed in the garden across the whole season, and abundance was greater in Triticum spp., Brassica spp., Prunus persica and Asclepias syriaca. Accordingly, a possible set of plants with scalar flowering enabling to guarantee the year-round presence of ladybirds in the urban garden is presented.