Effects of alternative male mating strategies on characteristics of sperm production in the Atlantic salmon (Salmo salar): Theoretical and empirical investigations

被引:196
作者
Gage, MJG
Stockley, P
Parker, GA
机构
关键词
D O I
10.1098/rstb.1995.0173
中图分类号
Q [生物科学];
学科分类号
07 ; 0710 ; 09 ;
摘要
Atlantic salmon (Salmo salar) males mature as either tiny precocious parr before seaward migration, or as older and larger anadromous males. Anadromous males dominate the spawning redds and aggressively defend females against parr intrusions. Parr gain fertilizations by sneaking in to ejaculate while anadromous males and females spawn. Such differences in mating advantage generate asymmetries in risk of sperm competition between the male strategies. Theoretical sperm competition models predict that males typically mating in disfavoured roles (here, the parr strategy) should be selected to offset this disadvantage by investing more into spermatogenesis to achieve fertilization success. First, we present a theoretical model which analyses gametic expenditure for salmon parr and anadromous male reproductive strategies. We then use the natural variance in mating pattern within this species to compare empirically how males invest in spermatogenesis. A range of reproductive traits were measured for both male strategies. Absolutely, anadromous males have larger testes and produce greater numbers of sperm than parr males. However, results show that parr invest relatively more heavily into total spermatogenesis, and have a larger gonosomatic index than anadromous males. Relative to body size, parr produced greater numbers of sperm and volumes of stripped ejaculate. There was no difference in sperm length between the two male strategies. However, more sperm were motile in parr ejaculates, and these sperm lived longer than anadromous male sperm. Our findings may explain how male parr, under elevated risks of sperm competition and occupying a disfavoured mating role (parr weigh only 0.15% of the average body mass of anadromous males) achieve disproportionately high fertilization success.
引用
收藏
页码:391 / 399
页数:9
相关论文
共 50 条
[31]  
Mills D, 1989, ECOLOGY MANAGEMENT A
[32]   TESTES SIZE, EJACULATE QUALITY AND SPERM COMPETITION IN BIRDS [J].
MOLLER, AP .
BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, 1988, 33 (03) :273-283
[33]   EJACULATE QUALITY, TESTES SIZE AND SPERM COMPETITION IN PRIMATES [J].
MOLLER, AP .
JOURNAL OF HUMAN EVOLUTION, 1988, 17 (05) :479-488
[34]   MATING OF ANADROMOUS ATLANTIC SALMON, SALMO-SALAR L, WITH MATURE MALE PARR [J].
MYERS, RA ;
HUTCHINGS, JA .
JOURNAL OF FISH BIOLOGY, 1987, 31 (02) :143-146
[35]   VARIATION IN MALE PARR MATURATION WITHIN AND AMONG POPULATIONS OF ATLANTIC SALMON, SALMO-SALAR [J].
MYERS, RA ;
HUTCHINGS, JA ;
GIBSON, RJ .
CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES, 1986, 43 (06) :1242-1248
[37]   SPERM COMPETITION GAMES - SPERM SIZE AND SPERM NUMBER UNDER ADULT CONTROL [J].
PARKER, GA .
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES, 1993, 253 (1338) :245-254
[38]   SPERM COMPETITION GAMES - RAFFLES AND ROLES [J].
PARKER, GA .
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES, 1990, 242 (1304) :120-126
[40]   ANIMAL BEHAVIOR AS A STRATEGY OPTIMIZER - EVOLUTION OF RESOURCE ASSESSMENT STRATEGIES AND OPTIMAL EMIGRATION THRESHOLDS [J].
PARKER, GA ;
STUART, RA .
AMERICAN NATURALIST, 1976, 110 (976) :1055-1076