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Sexual conflict in action: An antagonistic relationship between maternal and paternal sex allocation in the tammar wallaby, Notamacropus eugenii


Edwards, AM and Cameron, EZ and Deakin, JE and Ezaz, T and Pereira, JC and Ferguson-Smith, MA and Robert, KA, Sexual conflict in action: An antagonistic relationship between maternal and paternal sex allocation in the tammar wallaby, Notamacropus eugenii, Ecology and Evolution, 9, (8) pp. 4340-4348. ISSN 2045-7758 (2019) [Refereed Article]


Copyright Statement

Copyright 2018 The Authors. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0)

DOI: doi:10.1002/ece3.4813


Sex ratio biases are often inconsistent, both among and within species and populations. While some of these inconsistencies may be due to experimental design, much of the variation remains inexplicable. Recent research suggests that an exclusive focus on mothers may account for some of the inconsistency, with an increasing number of studies showing variation in sperm sex ratios and seminal fluids. Using fluorescent in‐situ hybridization, we show a significant population‐level Y‐chromosome bias in the spermatozoa of wild tammar wallabies, but with significant intraindividual variation between males. We also show a population‐level birth sex ratio trend in the same direction toward male offspring, but a weaning sex ratio that is significantly female‐biased, indicating that males are disproportionately lost during lactation. We hypothesize that sexual conflict between parents may cause mothers to adjust offspring sex ratios after birth, through abandonment of male pouch young and reactivation of diapaused embryos. Further research is required in a captive, controlled setting to understand what is driving and mechanistically controlling sperm sex ratio and offspring sex ratio biases and to understand the sexually antagonistic relationship between mothers and fathers over offspring sex. These results extend beyond sex allocation, as they question studies of population processes that assume equal input of sex chromosomes from fathers, and will also assist with future reproduction studies for management and conservation of marsupials.

Item Details

Item Type:Refereed Article
Keywords:Macropus eugenii, maternal, offspring sex ratio, paternal, sperm sex ratio, sex allocation
Research Division:Biological Sciences
Research Group:Evolutionary biology
Research Field:Life histories
Objective Division:Environmental Management
Objective Group:Terrestrial systems and management
Objective Field:Terrestrial biodiversity
UTAS Author:Edwards, AM (Dr Amy Edwards)
ID Code:132556
Year Published:2019
Web of Science® Times Cited:2
Deposited By:Zoology
Deposited On:2019-05-13
Last Modified:2019-10-29
Downloads:11 View Download Statistics

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