The genus Theope Doubleday, 1847 comprises 77 species occurring from central Mexico to Northern Argentina (Hall 1999, 2008; Jauffret & Jauffret 2009). Life histories have been described for only about of 12% of the species in the genus (Hall 1999, 2002; Kaminski 2006). All known larvae are myrmecophilous, and nearly always associated with ants of the genus Azteca Forel (Dolichoderinae) (DeVries et al. 1994; DeVries 1997; Hall 1999; but see Kaminski 2006 for Theope thestias Hewitson, 1860 being facultatively tended by several Formicinae and Myrmicinae). Reported larval host plants for the genus Theope include thirteen plant families (DeVries et al. 1994; Hall 1999; Kaminski 2006; Beccaloni et al. 2008; Janzen & Hallwachs 2010).
The present paper reports additional food plant records for a population of Theope lycaenina Bates, 1868 (Fig. 1A) and larval feeding behavior in a coastal locality in Southeastern Brazil. Observations were carried out in the region of the Praia da Fazenda, in the Nucleo Picinguaba of the Serra do Mar State Park, in Ubatuba municipality, Sao Paulo State (23°21′S, 44°50′W), from 2004 to 2007 (always in January), and July 2010. Most observed larvae were brought to the laboratory and reared to adults for species identification. Ant vouchers are deposited in the following Brazilian museums: Museu de Zoologia da USP, Sao Paulo, and Museu de Zoologia da Unicamp, Campinas. Adult vouchers of the butterfly are deposited in the Museu de Zoologia da Unicamp, Campinas.
In January 2004, two larvae were observed feeding on an unidentified Sapindaceae vine, tended by workers of Azteca chartifex Forel, 1896 (Fig. 1B), which lived in a large carton nest on a tall nearby tree. In 2005 to 2007, eight additional larvae were observed, always using the same host plant species, and likewise tended by A. chartifex ants. In July 2010, an intensive 10 days search was done on three additional plants (distant more than 10 m from each other) that each harbored a colony of A. chartifex, which were easily found by the presence of carton nests and by the large number of ant workers patrolling the whole plants. Each of these plants also harbored larvae of T. lycaenina, including Andira fraxinifolia Benth. (Fabaceae) (on which three third instars were found), Morus nigra L. (Moraceae) (one second instar) and Malvaviscus arboreus Cav.
(Malvaceae) (two first instar and one third instar). The last two plant families are also new plant family records for Theope, and these new records increase to four the number of families used by this species in the study area, and to eight the number of plant families used by T. lycaenina over its range (Beccaloni et al. 2008; L. A. Kaminski pers. comm.). In all cases the larvae, including the small first instars, always were observed being tended by at least two Azteca workers (Fig. 1B). No larvae were ever found on neighboring host-plants of the same species that had no ants present. In A. fraxinifolia, two third instars were observed on the surface of dead twigs consuming the superficial tissues.
Results strongly suggest that larvae of T. lycaenina are highly dependent on Azteca ants to develop and grow, confirming the pattern observed for most known species in the genus Theope. In addition, by using hosts belonging to four different plant families in a single place, T. lycaenina can be considered locally polyphagous. Since the presence of larvae is apparently highly correlated with the presence of Azteca ants, it is possible that polyphagy in T. lycaenina is mediated by the presence of particular ant taxa, similar to what has been proposed for other myrmecophilous riodinids (DeVries et al. 1994; DeVries 1997; Hall & Harvey 2001; Kaminski 2008). Also, the behavior of feeding on dead plant tissues could be an additional factor that promotes polyphagy in this species, because they would be less selective by specific secondary substances of their host plants. These observations reinforce the idea that ant presence can be a major factor influencing host plant choice in species with obligate symbiotic associations (e.g., DeVries et al. 2004; Kaminski 2008).
Lucas A. Kaminski, Curtis Callaghan, Luisa L. Mota, Carla Penz, Keith Willmott and Niklas Wahlberg made useful com- ments on the manuscript. Rogério R. Silva identified the Azteca species and Curtis Callaghan identified the Theope species. This research was supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, 04/05269-9), CNPq (300282/2008-7), and the National Science Foundation (DEB- 0527441).