Mutualistic interactions between Upiga virescens (Pyralidae), a pollinating seed-consumer, and Lophocereus schottii (Cactaceae)

Pollinating seed-consuming interactions are rare, but include fig-fig wasp and yucca-yucca moth interactions, both of which are thought to be coevolve d. Conditions favoring such mutualisms are poorly known but likely include plants and pollinators whose life cycles are synchronized. In this paper, w e describe a new pollinating seed-consumer mutualism between a Sonoran Dese rt cactus, Lophocereus schottii (senita cactus), and a pyralid moth, Upiga virescens (senita moth). We compare this mutualism with the yucca mutualism in terms of Life history traits, active pollination, and selective abortio n. Senita cactus flowers were pollinated nearly exclusively by nocturnal se nita moths, but a few halictid bees also pollinated flowers. Only 40% of fl owers set fruit during the years of study, apparently due to resource limit ation. All phases of the senita moth's life history were associated with th e senita cactus. During flower visitation, female senita moths collected po llen, actively pollinated flowers, and oviposited one egg. After flowers cl osed, emerging larvae bored into the tops of developing fruit, where they c onsumed seeds and fruit tissue. However, not all seeds/fruit were consumed by larvae because only 20% of eggs produced larvae that survived to be seed /fruit consumers. Senita cactus and senita moth interactions were mutualist ic. Moths received food resources (seeds, fruit) for their progeny, and cac ti had a 4.8 benefit-to-cost ratio; only 21% of developing fruit were destr oyed by larvae. Life history traits important to this mutualism included lo w survival of senita moth eggs/larvae, several moth generations per floweri ng season, host specificity of senita moths, active pollination, ovipositio n into flowers, and limited seed/fruit consumption. Active pollination by s enita moths in the presence of co-pollinators supports the prediction that active pollination can evolve during a period of coexistence with co-pol li nators. The specialization of both senita and senita moths in the presence of co-pollinators makes the senita mutualism quite remarkable in comparison with fig-fig wasp and yucca-yucca moth mutualisms.