Ants (Hymenoptera, Formicidae) may play an important economic role in citrus orchards, either by causing damage in trees or induce pest’s outbreaks, due to interactions with injurious honeydew-producing insects, or even by being potential predators of other arthropods. In order to deepen knowledge about the ant species associated to citrus orchards, in the southern region of Portugal, Algarve, samples were collected in 49 citrus orchards, along the subregions of Litoral, Barrocal and Serra, between July and August 2007. In all, 2812 ants were identified comprising 12 different genera and 26 species. The most common species were Linepithema humile (Mayr), Plagiolepis pygmaea Latreille and Pheidole pallidula (Nylander). Nineteen species are reported for the first time in citrus, in Portugal, and ten are first records, in citrus, in the world. The higher number of species was found in the Serra subregion, with 19 species. Regarding economic importance, special attention must be paid to the phytophagous ants of Tapinoma genus, that can originate direct damage, and the argentine ant, L. humile, which interferes with the activity of natural enemies, disrupting biological control of pests.

Mestrado em Engenharia Agronómica - Instituto Superior de Agronomia