First host plant record for Strymon davara (Hewitson) (Lepidoptera, Lycaenidae) in the highly human-modified coastal valleys of the Atacama Desert

Some native plants can survive the disturbances associated with agricultural activities, sometimes being considered weeds and objects of control practices. However, these plants can be very important to support populations of native insects in disturbed habitats. Alternanthera halimifolia (Lam.) Standl. (Amaranthaceae) is locally considered a weed, and here it is reported as the first host plant known for the Neotropical hairstreak Strymon davara (Hewitson, 1868) based on research performed in the coastal valleys of the Atacama Desert of northern Chile. Furthermore, field observations suggest that this is the only host of S. davara in this area. This case provides an example of the importance of a weed in the conservation of local populations of a butterfly in a highly human-modified environment.