Coexisting Patterns and Foraging Behavior of Introduced and Native Ants (Hymenoptera Formicidae) in the Galapagos Islands (Ecuador)

Resumen

One of the major ecological problems of the Galapagos Islands is the accidental introduction of exotic species by man. Giant endemic cacti are the most conspicuous plants in the xeromorphic zone of many of the Galapagos Islands. Their numerous floral nectaries and permanent fruits represent an important and reliable food source for various birds and many insects. On Santa Cruz Island, at the Charles Darwin Research Station study site, W. auropunctata was the dominating ant species on cacti before and shortly after El Nino Southern Oscillation in 1982-83. Island biotas remote from continents usually contain relatively few species. Their fragile biological equilibrium is therefore highly sensitive to large oscillations or changes in climate and to newly introduced species. W. M. Wheeler described the endemic C. macilentus and C. planus as the most abundant ant species in the xeromorphic parts of the islands.