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Title: Reproductive and resource benefits to large female body size in a mammal with female-biased sexual size dimorphism

Abstract

Factors underlying the evolution of female-biased sexual size dimorphism in mammals are poorly understood. In an effort to better understand these factors we tested whether larger female southern flying squirrels, Glaucomys volans, gained reproductive advantages (larger litters or more male mates) and direct resource benefits, such as larger home ranges or access to more food (i.e. mast-producing trees). As dimorphism can vary with age in precocial breeding species, we compared females during their first reproduction and during a subsequent breeding attempt. Females were not significantly larger or heavier than males at first reproduction, but became about 7% heavier and 22% larger than males at subsequent breeding. Larger females produced larger litters and had home ranges containing a greater proportion of upland hardwood trees. Female body size was not associated with either multiple male mating or home range size, but females with larger home ranges had higher indexes of body condition. Females in precocial breeding flying squirrels initiate reproduction before sexual size dimorphism is evident, and thus, may be allocating resources to both reproduction and growth simultaneously, or delaying growth entirely. Larger females produce more pups and have access to more food resources. Thus, selection for increased female size may partlymore » explain how female-biased sexual size dimorphism is maintained in this species.« less

Authors:
Publication Date:
Research Org.:
Savannah River Ecology Laboratory (SREL), Aiken, SC
Sponsoring Org.:
USDOE
OSTI Identifier:
908668
Report Number(s):
SREL-3037
TRN: US200722%%743
DOE Contract Number:
DE-FC09-07SR22506
Resource Type:
Journal Article
Resource Relation:
Journal Name: Animal Behavior; Journal Volume: 73
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; BREEDING; FEMALES; HOME RANGE; MALES; MATING; REPRODUCTION; SQUIRRELS; SIZE

Citation Formats

Fokidis, H.B., T.S. Risch and T.C. Glenn. Reproductive and resource benefits to large female body size in a mammal with female-biased sexual size dimorphism. United States: N. p., 2007. Web. doi:10.1016/j.anbehav.2006.08.010.
Fokidis, H.B., T.S. Risch and T.C. Glenn. Reproductive and resource benefits to large female body size in a mammal with female-biased sexual size dimorphism. United States. doi:10.1016/j.anbehav.2006.08.010.
Fokidis, H.B., T.S. Risch and T.C. Glenn. Mon . "Reproductive and resource benefits to large female body size in a mammal with female-biased sexual size dimorphism". United States. doi:10.1016/j.anbehav.2006.08.010.
@article{osti_908668,
title = {Reproductive and resource benefits to large female body size in a mammal with female-biased sexual size dimorphism},
author = {Fokidis, H.B., T.S. Risch and T.C. Glenn},
abstractNote = {Factors underlying the evolution of female-biased sexual size dimorphism in mammals are poorly understood. In an effort to better understand these factors we tested whether larger female southern flying squirrels, Glaucomys volans, gained reproductive advantages (larger litters or more male mates) and direct resource benefits, such as larger home ranges or access to more food (i.e. mast-producing trees). As dimorphism can vary with age in precocial breeding species, we compared females during their first reproduction and during a subsequent breeding attempt. Females were not significantly larger or heavier than males at first reproduction, but became about 7% heavier and 22% larger than males at subsequent breeding. Larger females produced larger litters and had home ranges containing a greater proportion of upland hardwood trees. Female body size was not associated with either multiple male mating or home range size, but females with larger home ranges had higher indexes of body condition. Females in precocial breeding flying squirrels initiate reproduction before sexual size dimorphism is evident, and thus, may be allocating resources to both reproduction and growth simultaneously, or delaying growth entirely. Larger females produce more pups and have access to more food resources. Thus, selection for increased female size may partly explain how female-biased sexual size dimorphism is maintained in this species.},
doi = {10.1016/j.anbehav.2006.08.010},
journal = {Animal Behavior},
number = ,
volume = 73,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}