title: A parent-of-origin effect on honeybee worker ovary size.
abstract: Apis mellifera capensis is unique among honeybees in that unmated workers can produce pseudo-clonal female offspring via thelytokous parthenogenesis. Workers use this ability to compete among themselves and with their queen to be the mother of new queens. Males could therefore enhance their reproductive success by imprinting genes that enhance fertility in their daughter workers. This possibility sets the scene for intragenomic conflict between queens and drones over worker reproductive traits. Here, we show a strong parent-of-origin effect for ovary size (number of ovarioles) in reciprocal crosses between two honeybee subspecies, A. m. capensis and Apis mellifera scutellata. In this cross, workers with an A. m. capensis father had 30% more ovarioles than genotypically matched workers with an A. m. scutellata father. Other traits we measured (worker weight at emergence and the presence/absence of a spermatheca) are influenced more by rearing conditions than by parent-of-origin effects. Our study is the first to show a strong epigenetic (or, less likely, cytoplasmic maternal) effect for a reproductive trait in the honeybee and suggests that a search for parent-of-origin effects in other social insects may be fruitful.
authors.affiliation: Behaviour and Genetics of Social Insects Laboratory, School of Biological Sciences, University of Sydney, , Sydney, New South Wales 2006, Australia, Honey Bee Research Section, ARC-Plant Protection Research Institute, , Private Bag X5017, Stellenbosch 7599, South Africa, Department of Biology, Harvey Mudd College, , 301 Platt Boulevard, Claremont, CA 91001, USA.
authors.forename: Benjamin P
authors.initials: BP
authors.lastname: Oldroyd
authors.forename: Michael H
authors.initials: MH
authors.lastname: Allsopp
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Roth
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Remnant
authors.forename: Robert A
authors.initials: RA
authors.lastname: Drewell
authors.forename: Madeleine
authors.initials: M
authors.lastname: Beekman
mesh_terms: D000818:Animals; D001516:Bees / Q000033:anatomy & histology* / Q000235:genetics; D003433:Crosses, Genetic; D044127:Epigenesis, Genetic; D005260:Female; D008297:Male; D009929:Organ Size; D010053:Ovary / Q000033:anatomy & histology; D010312:Parthenogenesis; D012098:Reproduction
keywords: Apis mellifera capensis; imprinting; interspecific crosses; intragenomic conflict; parent-of-origin effects; reciprocal effects