Influence of urbanisation and plants on the diversity and abundance of aphids and their ladybird and hoverfly predators in domestic gardens

• Published in: European journal of entomology Vol. 115; no. 1; pp. 140 - 149
• Main Authors: ROCHA, Elise A., N.F. SOUZA, Estevao, A.D. BLEAKLEY, Lewis, BURLEY, Christopher, MOTT, Jade L., RUE-GLUTTING, Gloria, D.E. FELLOWES, Mark
• Format: Journal Article
• Language: English
• Published: Ceske Budejovice Institute of Entomology 01.01.2018; Institute of Entomology, Biology Centre, Czech Academy of Science
• Subjects: Abundance; Aphididae; Aphis fabae; Arthropods; Biodiversity; Coccinellidae; Coleoptera; Diptera; diversity; Ecology; Ecosystems; Environmental factors; Flowers & plants; Gardens; Gardens & gardening; Hemiptera; Herbivores; Host plants; Insects; Land cover; Land use; Plant diversity; Predators; Prey; species interactions; Species richness; Syrphidae; Taxa; Urban areas; urban ecology; Urban farming; Urbanization
• ISSN: 1210-5759; 1802-8829
• DOI: 10.14411/eje.2018.013

Urban gardens can harbour a high diversity of insects, which are critically important components of urban ecosystems. In this work, we investigate the richness and diversity of a major taxon of economic and ecological importance, the aphids (Hemiptera: Aphididae), and their main insect predators, the hoverflies (Diptera: Syrphidae) and ladybirds (Coleoptera: Coccinellidae), in urban gardens. We examined how variation in environmental factors associated with urbanisation (garden host plant abundance, garden plant richness, garden size, proportion of impervious surfaces in the surrounding area) directly and indirectly (via prey and predator abundance) infl uence the local diversity and abundance of aphids, ladybirds, and hoverfl ies. Sixty-seven domestic gardens located in southern England were surveyed during the peak period of aphid abundance, and the numbers and identity of aphids and their predators were recorded. We observed 45 aphid species (179917 individuals in total), 15 hoverfl y species (494 individuals) and 8 ladybird species (173 individuals). We found that aphid species richness and abundance were positively associated with utilised host plant abundance and garden plant species richness. Hoverfly abundance was positively correlated with garden plant richness. The abundance of ladybirds was positively correlated with aphid abundance and garden plant species richness, and negatively associated to the proportion of impervious surfaces in the surrounding environment. The difference in responses between the two major taxa of aphid predators may refl ect differences in their behaviour and natural history. Our results indicate that overall increases in urban land cover are not favourable for ladybirds as a group, and that fi ne scale habitat variables that are determined by garden owners have the potential to greatly affect the diversity of aphids and their primary predators.