Ornamental Annuals and Perennials Differ as Insect Attractors

Plant and floral resources can be used to attract beneficial and pollinating insects, which can reduce pesticide inputs. The use of ornamental landscapes can offer additional ecosystem benefits such as weed suppression and conservation of biodiversity.  A total of 65 plant types were evaluated in the Conservation Garden on University of Georgia Griffin Campus. Plants were chosen based on factors including high production of pollen and nectar, attractiveness to beneficial and pollinating insects, flowering phenology, and availability of floral resources. Plants located throughout the garden were monitored biweekly for one hour and visual observations consisted of family and order of beneficial and pollinating insects observed, plant or location insects visited, and ecological classification of the insects. Each insect order had fifteen top plant resources that functioned as arthropod “attractors”. Insect orders observed throughout the garden consisted of Lepidoptera (butterflies and moths), Diptera (flies), Hymenoptera (bees, wasps, and ants), Coleoptera (beetles), Araneae (spiders), and Hemiptera (true bugs, planthoppers, assassin bugs, stink bugs and others). All orders contain predatory, parasitoid, and foraging species that provide arthropod-mediated ecosystem services such as pollination and pest control. Differences between ornamentals were found with regard to types of insects attracted to a particular plant species. Top Lepidoptera attractors were: Agastache 'Black Adder', Lantana 'Miss Huff', Lantana 'Mozelle', Verbena bonariensis, and Buddleja. Top Aranae attractors were Rudbeckia 'Goldsturm', Amsonia hubrictii, Bellamcanda, Gaura 'Passionate Blush', Nepeta 'Walker's Low', and Chrysanthemum 'Cambodian Queen'. Top Diptera attractors were: Foeniculum vulgare, Coreopsis 'Red Shift', Bellamcanda, Aster 'Wood's Pink', and Gaura 'Passionate Blush'. Top Hymenoptera attractors were Agastache 'Acapulco', and 'Black adder', Nepeta 'Walker's Low', Salvia 'Hot Lips' and 'Mystic Spires', and Gaura 'Passionate Blush'. Top Coleoptera attractors were: Achillea 'Coronation Gold' and 'Seduction Yellow', Coreopsis 'Red Shift', Gaura 'Passionate Blush', and Rudbeckia triloba. Top Hemiptera attractors were Buddleja, Achillea 'Coronation Gold', Curcuma ' White Emperor', Rudbeckia triloba, Coreopsis 'Red Shift', and Cassia hebecarpa.