Manduca sexta is probably an important pollinator in desert regions and of Platanthera orchids elsewhere. In the American Southwest, this and other Manduca are native, resident species, breeding mostly in riparian habitats during the summer rainy season. This moth is usually not associated with natural habitats east of about Texas, although Datura growing in recently abandoned or at least recently plowed, old fields are used as foodplants as far east as New Jersey (Dale Schweitzer), where some of these might be native. Manduca sexta is primarily a crop pest (the most common hornworm on tomato) eastward where it is usually controlled by insecticides, native parasitoids, and plowing of the pupae, in farmlands to the extent it is common, but does not reach high densities. Despite dependence on anthropogenic habitats, eastern US populations are apparently not dependent on migration, and pupae do survive in regions with cold winters (Schweitzer, 2006). Phenology is well-adapted to local climate and crop phenology. In eastern North America, Manduca sexta has probably evolved as primarily a crop pest for thousands of years, at first mostly on tobaccos, later on tomatoes, potatoes and others. Adaptation to the short mid summer growing season of the arid southwestern USA and northern Mexico probably facilitated adaptation to the somewhat longer summer tobacco growing season farther east. In practice then if this species were identified as an important pollinator northeast of the southwestern desert regions, managing for it would be problamatic to impractical since no natural communities would likely support larvae. In desert regions maintaining healthy populations of native Solanaceae (and he exotic tree tobacco) should suffice for M. sexta.
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