A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
MALE CHOICE AND MALE-MALE COMPETITION IN IDOTEA-BALTICA (CRUSTACEA, ISOPODA)
Tekijät: Jormalainen V, Merilaita S, Tuomi J
Kustantaja: BLACKWELL WISSENSCHAFTS-VERLAG GMBH
Julkaisuvuosi: 1994
Journal: Ethology
Tietokannassa oleva lehden nimi: ETHOLOGY
Lehden akronyymi: ETHOLOGY
Vuosikerta: 96
Numero: 1
Aloitussivu: 46
Lopetussivu: 57
Sivujen määrä: 12
ISSN: 0179-1613
DOI: https://doi.org/10.1111/j.1439-0310.1994.tb00880.x
Tiivistelmä
Sexual selection in mate-guarding Crustacea may involve several processes: male choice, male-male competition, and female choice. To evaluate the relative importance of the different processes in mate choice of the aquatic isopod I. baltica we studied 1) the mate-choice criteria of males, 2) effects of sex ratio on the outcome of the mating contest, and 3) the role of size in male-male interactions. When given a choice between a small and a large female, males most often chose the one that matured earlier for parturial ecdysis. Maturity was a more important choice criterion than female size, but these also correlated positively. Large males had a mating advantage in both male- and female-biased sex ratios; pairing was size-assortative only in the male-biased ratio where guarding was also longer. If an extra male was placed with a precopulatory pair, 30 % take-overs occurred, large males surpassing. Present and earlier work suggests that male size is an asset in both intra- and intersexual interactions. There is little or no direct phenotypic sexual selection on female size: sexual selection for large males presumably contributes to the evolution of sexual size dimorphism in I. baltica.
Sexual selection in mate-guarding Crustacea may involve several processes: male choice, male-male competition, and female choice. To evaluate the relative importance of the different processes in mate choice of the aquatic isopod I. baltica we studied 1) the mate-choice criteria of males, 2) effects of sex ratio on the outcome of the mating contest, and 3) the role of size in male-male interactions. When given a choice between a small and a large female, males most often chose the one that matured earlier for parturial ecdysis. Maturity was a more important choice criterion than female size, but these also correlated positively. Large males had a mating advantage in both male- and female-biased sex ratios; pairing was size-assortative only in the male-biased ratio where guarding was also longer. If an extra male was placed with a precopulatory pair, 30 % take-overs occurred, large males surpassing. Present and earlier work suggests that male size is an asset in both intra- and intersexual interactions. There is little or no direct phenotypic sexual selection on female size: sexual selection for large males presumably contributes to the evolution of sexual size dimorphism in I. baltica.
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