low larval survival rate and the great benefit of the senita moth to pollination and fruit set, the benefits to the senita cactus of interaction with the senita moth are three to four times the cost of seed destruction. Parasitism A significant proportion, 12 to 17%, of moths that survive to pupation are killed by endoparasitic wasps. Endoparasitic wasps oviposit on the body of the host, the larvae killing the host upon hatching. Mutualism The senita moth is an obligate mutualist with the senita cactus. Pollination of the senita cactus is dependent on the senita moth, with 75 to 95% of cactus fruit set resulting from nocturnal pollination by the senita moth. The remaining fruit set is resultant from daytime pollination by co-pollinators. The senita moth is, in turn, reliant on the senita cactus for oviposition and larval food sources. This mutualistic relationship is present throughout the senita moth's range, which suggests there is strong selective pressure on traits that maintain mutualism. Coevolution Several traits of the senita cactus allowed for the coevolution of mutualism with the senita moth. The first is nocturnal flower opening, which favors interactions with the cactus's only nocturnal pollinator, the senita moth. The second trait is self-incompatibility of the host plant, which leads to a reliance on pollinators for reproduction. The third trait is resource-limited fruit production with a reduction in nectar production. Reduced nectar production suggests a lessened need to attract pollinators, as would be the case in obligate mutualism where pollinators rely on the host plant for reproduction. Comparison to other obligate pollinators The senita moth is the sixth known example of pollination with seed consumption, and the third known example of obligate pollination with seed consumption. Senita cactus and senita moth mutualism is similar to the mutualism seen with figs and fig wasps and yuccas and yucca moths. The senita moth's mutualism is unique in that it is not the sole pollinator of its host plant; the senita cactus is pollinated by a few species of bees in addition to the senita moth. This is atypical of specialized, obligate mutualism, and could suggest that the senita cactus is in an evolutionary transition state from a general mutualism with co-pollinators to a complete reliance on the senita moth for pollination. References Crambidae genus list at Butterflies and Moths of the World of the Natural History Museum Glaphyriinae Crambidae genera Taxa named by Hahn