title: The dynamic association between ovariole loss and sterility in adult honeybee workers.
abstract: In the social insects, ovary state (the presence or absence of mature oocytes) and ovary size (the number of ovarioles) are often used as proxies for the reproductive capacity of an individual worker. Ovary size is assumed to be fixed post-eclosion whereas ovary state is demonstrably plastic post-eclosion. Here, we show that in fact ovary size declines as honeybee workers age. This finding is robust across two honeybee species:Apis melliferaandA. ceranaThe ovariole loss is likely to be due to the regression of particular ovarioles via programmed cell death. We also provide further support for the observation that honeybee workers with activated ovaries (mature oocytes present) most commonly have five ovarioles rather than a greater or smaller number. This result suggests that workers with more than five ovarioles are unable to physiologically support more than five activated ovarioles and that workers with fewer than five ovarioles are below a threshold necessary for ovary activation. As a worker's ovariole number declines with age, studies on worker ovariole number need to take this plasticity into account.
authors.affiliation: Behaviour and Genetics of Social Insects Laboratory, School of Biological Sciences A12, University of Sydney, Sydney, New South Wales 2006, Australia isobel.ronai@sydney.edu.au.
authors.forename: Isobel
authors.identifier: http://orcid.org/0000-0002-1658-857X
authors.initials: I
authors.lastname: Ronai
authors.affiliation: Honeybee Research Section, ARC-Plant Protection Research Institute, Private Bag X5017, Stellenbosch 7599, Western Cape, South Africa.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Allsopp
authors.affiliation: Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Science, Kunming, Yunnan Province 650223, People's Republic of China.|Eastern Bee Research Institute of Yunnan Agricultural University, Heilongtan, Kunming, Yunnan Province 650201, People's Republic of China.
authors.forename: Ken
authors.initials: K
authors.lastname: Tan
authors.affiliation: Eastern Bee Research Institute of Yunnan Agricultural University, Heilongtan, Kunming, Yunnan Province 650201, People's Republic of China.
authors.forename: Shihao
authors.initials: S
authors.lastname: Dong
authors.affiliation: Eastern Bee Research Institute of Yunnan Agricultural University, Heilongtan, Kunming, Yunnan Province 650201, People's Republic of China.
authors.forename: Xiwen
authors.initials: X
authors.lastname: Liu
authors.affiliation: Behaviour and Genetics of Social Insects Laboratory, School of Biological Sciences A12, University of Sydney, Sydney, New South Wales 2006, Australia.
authors.forename: Vanina
authors.initials: V
authors.lastname: Vergoz
authors.affiliation: Behaviour and Genetics of Social Insects Laboratory, School of Biological Sciences A12, University of Sydney, Sydney, New South Wales 2006, Australia.
authors.forename: Benjamin P
authors.identifier: http://orcid.org/0000-0001-6831-3677
authors.initials: BP
authors.lastname: Oldroyd
mesh_terms: D000818:Animals; D017209:Apoptosis; D001516:Bees / Q000502:physiology*; D005260:Female; D007246:Infertility; D010053:Ovary / Q000502:physiology*; D012098:Reproduction
keywords: honeybee; oogenesis; ovariole; reproductive capacity