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Tegeticula is one of the two genera of true yucca moths, which offer one of the classical cases of coevolved obligate mutualism between species. Females use unique tentacles on their maxillary palps to actively collect and compact pollen from the flowers of their yucca hosts. Yucca pollen is very sticky, and it adheres (without aid of the tentacles) to the underside of her head. Once loaded, the female oviposits into yucca flowers, walking up to floral stigmas after oviposition and actively pollinating the flower with a small portion of her pollen batch. In so doing, she assures that lack of pollination will not cause the flower to abort. This is critical, because her progeny feed only on developing seeds. The larvae only feed on a modest proportion of the seeds, thus making it possible for this herbivore to actually be of net benefit to its host. Over evolutionary time, yucca moths and yuccas have evolved complete mutual dependence on each other (Riley 1892, Pellmyr et al 1996b).
A considerable body of literature has accumulated on ecological and evolutionary aspects of the yucca-yucca moth interaction; a comprehensive reference list for the early literature is provided in Davis (1967), and much of the subsequent work is referenced in Powell (1992) and Pellmyr et al (1996). Recent empirical work has focused on the stability of obligate mutualism (Pellmyr and Huth 1994, Richter and Weis 1995), reversal of mutualism (Pellmyr et al 1996a), and moth behavioral plasticity in pollination and egg dispersal decisions (Addicott and Tyre 1995).
Recently the species traditionally called T. yuccasella has been identified as being a complex of at least 13 species, many of which have very distinctive biology. Among them are two non-pollinating species of 'cheater yucca moths'. The reader should bear in mind that many papers written before the recent revision that provide, e.g., measures of seed consumption, actually provide composite measurements of all coexisting species. This problem only applies to the yuccasella complex ("the white species").