Insects on urban plants: contrasting the flower head feeding assemblages on native and exotic hosts
- 406 Downloads
Exotic plant species very often comprise a large proportion of urban floras. Because herbivorous insects depend on the presence of suitable host plants to maintain their populations, it is imperative to elucidate the relative importance of native and exotic hosts to understand the response of herbivorous guilds to urbanization. By using a plant-herbivore system composed of Asteraceae hosts and flower-head endophagous insects, we investigated whether the diversity and composition of herbivorous insects differs between native and exotic host-plant species in an urban environment. Although we found only seven exotic Asteraceae among the 30 species recorded, the overall abundance of exotics was considerably greater than that of native host plants. Overall, the exotic host species supported a small subset of the herbivore assemblage found on the native ones. The number of herbivore species per host species was significantly higher among the native plants, but we did not find a difference in herbivore abundance. Moreover, the higher taxonomic composition of herbivores on exotic Asteraceae was reduced, being composed of only three genera and two families from a total of 16 genera and six families of herbivores. These results provide support for the idea that plants outside of their original geographic distribution have lower loads of enemies than phylogenetically related native species. Our findings indicate that native host plants in urban areas play a critical role in supporting the native herbivorous insect fauna.
KeywordsAlien plants Cities Exotic species Invasive species Insect-plant interactions Phytophagous insects
We are grateful to Rosane Picon, Marina Braun and Ricardo Fabiano for helping us with field work. This study was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) grants # 04/15482-1 to TML, # 03/02541-0 and # 06/56889-2 to MAN, and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) grant # 306049/2004 to TML. RDL’s research is supported by CNPq.
- Almeida AM, Fonseca CR, Prado PI, Almeida-Neto M, Diniz S, Kubota U, Braun MR, Raimundo RLG, Anjos LA, Mendonça TG, Futada SM, Lewinsohn TM (2006) Assemblages of endophagous insects on Asteraceae in São Paulo cerrados. Neotrop Entomol 35:458–468. doi: 10.1590/S1519-566X2006000400006 PubMedCrossRefGoogle Scholar
- Batalha MA, Mantovani W (2000) Reproductive phenological patterns of cerrado plant species at the Pé-de-Gigante reserve (Santa Rita do Passa Quatro, SP, Brazil): a comparison between the herbaceous and woody floras. Rev Bras Biol 60:129–145. doi: 10.1590/S0034-71082000000100016 PubMedCrossRefGoogle Scholar
- Blank S (2010) Resampling stats for Excel v 4.00.statistics.comGoogle Scholar
- Fenner M, Lee WG (2001) Lack of pre-dispersal seed predators in introduced Asteraceae in New Zealand. New Zeal J Ecol 25:95–99Google Scholar
- Gagné RJ (1994) The Gall Midges of the Neotropical Region. Cornell University Press, IthacaGoogle Scholar
- Lewinsohn TM (1991) Insects in flower heads of Asteraceae in Southeast Brazil: a tropical case study on species richness. In: Price PW, Lewinsohn TM, Fernandes GW, Benson WW (eds) Plant-animal interactions: evolutionary ecology in tropical and temperate regions. Wiley-Interscience, New York, pp 525–559Google Scholar
- Marquis RJ (1991) Herbivore fauna of Piper (Piperaceae) in a Costa Rican wet forest: diversity, specifity, and impact. In: Price PW, Lewinsohn TM, Fernandes GW, Benson WW (eds) Plant-animal interactions: evolutionary ecology in tropical and temperate regions. Wiley/Interscience, New York, pp 179–208Google Scholar
- Prado PI, Lewinsohn TM, Almeida AM, Norrbom AL, Buys BD, Macedo AC, Lopes MB (2002) The fauna of Tephritidae (Diptera) from capitula of Asteraceae in Brazil. Proc Entomol Soc Wash 104:1007–1028Google Scholar
- Strong DR, Lawton JH, Southwood TRE (1984) Insects on plants. Blackwell, OxfordGoogle Scholar
- Zwölfer H, Romstöck-Völkl M (1991) Biotypes and evolution of niches in phytophagous insects on Carduae hosts. In: Price PW, Lewinsohn TM, Fernandes GW, Benson WW (eds) Plant-animal interactions: evolutionary ecology in tropical and temperate regions. Wiley/Interscience, New York, pp 487–507Google Scholar