Tegeticula

Abstract: The obligate pollination mutualism between yuccas (Agavaceae) and yucca moths (Lepidoptera, Prodoxidae), in which the adult moth pollinates yucca flowers and her progeny feed on developing seeds, is one of the classically cited examples of coevolution. While known since 1872, our understanding of the ecology and evolution of this association has increased dramatically in the past decade. Here I review current information on organismal diversity and phylogenetic relationships, ecological relationships, origin and reversal of the mutualism, and the potential for analyzing patterns of co-speciation and the historical role of coevolution on specific traits in driving diversification in the interaction. Major novel developments in recent years include the recognition of a large species complex of pollinators, previously thought to be one polyphagous species; a majority of all moth species are monophagous. Considerable life history diversity has been unveiled, and mechanisms that maintain a mutualistic equilibrium by preventing overexploitation documented. Phylogenetic and ecological information, including data from other, newly discovered facultative pollinators in the Prodoxidae, have been used to erect a hypothesis for the evolution of obligate mutualism. Application of a molecular clock to phylogenetic data suggests that the plant-moth association arose at least 40 Mya, and that the obligate mutualism evolved very quickly after this event. Two separate events of reversal of mutualism have been identified, involving derived ‘‘cheater’’ moth species that oviposit into fruits resulting from pollination by other pollinator species. This appears to have happened not through selection for cheating, but rather as a byproduct of a phenological shift to an unexploited seed resource, in which case pollination behavior became redundant. Analyses of parallel diversification and character coevolution are hampered by incomplete phylogenetic information at the species level, especially for the plants, but also for the pollinators. Available data indicate considerable deviation from strict co-speciation, and no evident examples of this process. Analyses of the role of coevolutionary processes in driving the diversification of yuccas and yucca moths will be possible once fully resolved phylogenies become available.

Abstract: Purposeful pollination of yucca by females of a moth that produces larvae that feed on some of the seeds is a classic example of plant-animal mutualism. Recent research has focused on the complex interspecific nature of this association. Pollinators are members of two genera with different oviposition and larval biologies. There appear to be several sibling species among populations of the pollinator that were formerly considered to be a single widespread generalist, and these may include sympatric nonpollinator 'cheaters'. Bogus yucca moths, members of a third genus, which neither transport pollen nor feed in the seed but depend upon the inflorescences, are niche specific and often host-species specific and include one leaf-mining species. Their larvae can spend many years in diapause before synchronized development.

Abstract: The yucca moths (Tegeticula and Parategeticula) are of great importance in studies of coevolution because of their obligate mutualism with their yucca hosts. Historically, three species of Tegeticula have been recognized. One of them, T. yuccasella, has been regarded as the pollinator of all but two yucca species, but morphological, molecular and biological data show that this is a large complex of monophagous and oligophagous species that differ greatly in their biology. It also includes derived 'cheater' species that do not pollinate their hosts and oviposit into fruits rather than flowers. Here the yuccasella complex north of Mexico is revised. The nominotypic pollinator species yuccasella is redescribed, and ten new pollinator species described: altiplanella, baccatella, carnerosanella, cassandra, elatella, maderae, mojavella, rostratella, superficiella and treculeanella. Two non-pollinating cheater species are recognized. One such species originally misidentified as a Prodoxus species, then synonymised with yuccasella, is re- erected as the non-pollinating intermedia. In addition, the new non-pollinator species corruptrix is described.