title: Phenotypic Variation in Fitness Traits of a Managed Solitary Bee, Osmia ribifloris (Hymenoptera: Megachilidae).
abstract: We investigated fitness in natural populations of a managed solitary bee Osmia ribifloris Cockerell (Hymenoptera: Megachilidae) from sites separated from 400 to 2,700 km. Parental wild bees originated in central Texas (TX), central-northern Utah (UT), and central California (CA). They were then intercrossed and raised inside a mesh enclosure in southern Mississippi (MS). Females from all possible mated pairs of O. ribifloris produced F1 broods with 30-40% female cocoons and outcrossed progeny were 30% heavier. Mitochondrial (COI) genomes of the four populations revealed three distinct clades, a TX-CA clade, a UT clade, and an MS clade, the latter (MS) representing captive progeny of CA and UT bees. Although classified as separate subspecies, TX and CA populations from 30° N to 38° N latitude shared 98% similarity in COI genomes and the greatest brood biomass per nest straw (600- to 700-mg brood). Thus, TX and CA bees show greater adaptation for southern U.S. sites. In contrast, UT-sourced bees were more distantly related to TX and CA bees and also produced ∼50% fewer brood. These results, taken together, confirm that adult O. ribifloris from all trap-nest sites are genetically compatible, but some phenotypic variation exists that could affect this species performance as a commercial blueberry pollinator. Males, their sperm, or perhaps a substance in their sperm helped stabilize our captive bee population by promoting legitimate nesting over nest usurpation. Otherwise, without insemination, 50% fewer females nested (they nested 14 d late) and 20% usurped nests, killing 33-67% of brood in affected nests.
authors.affiliation: USDA-ARS Thad Cochran Southern Horticultural Laboratory, 810 Hwy 26 West, Poplarville, MS 39470. blair.sampson@ars.usda.gov.
authors.forename: B J
authors.initials: BJ
authors.lastname: Sampson
authors.affiliation: USDA-ARS Thad Cochran Southern Horticultural Laboratory, 810 Hwy 26 West, Poplarville, MS 39470.
authors.forename: T A
authors.initials: TA
authors.lastname: Rinehart
authors.affiliation: USDA-FS Forest Products Laboratory, One Gifford Pinchot Dr., Madison, WI 53726.
authors.forename: G T
authors.initials: GT
authors.lastname: Kirker
authors.affiliation: USDA-ARS Thad Cochran Southern Horticultural Laboratory, 810 Hwy 26 West, Poplarville, MS 39470.
authors.forename: S J
authors.initials: SJ
authors.lastname: Stringer
authors.affiliation: USDA-ARS Thad Cochran Southern Horticultural Laboratory, 810 Hwy 26 West, Poplarville, MS 39470.
authors.forename: C T
authors.initials: CT
authors.lastname: Werle
mesh_terms: D000818:Animals; D001516:Bees / Q000235:genetics*; D029798:Blueberry Plants; D004272:DNA, Mitochondrial / Q000737:chemistry*; D005260:Female; D056084:Genetic Fitness; D008297:Male; D009425:Nesting Behavior; D010641:Phenotype
chemical_list: D004272:DNA, Mitochondrial
keywords: captivity; conservation; mtDNA; pollination; usurpation