Affordable Access

deepdyve-link
Publisher Website

Dimorphic ejaculates and sperm release strategies associated with alternative mating behaviors in the squid.

Authors
  • Apostólico, Lígia H1
  • Marian, José E A R1
  • 1 Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, Brazil. , (Brazil)
Type
Published Article
Journal
Journal of morphology
Publication Date
Nov 01, 2017
Volume
278
Issue
11
Pages
1490–1505
Identifiers
DOI: 10.1002/jmor.20726
PMID: 28722165
Source
Medline
Keywords
License
Unknown

Abstract

Sperm competition is a powerful postcopulatory selective force influencing male adaptations associated with increasing fertilization success, and it is usually related to the evolution of different strategies of ejaculate expenditure between individuals. Ejaculates may also be influenced by additional selective pressures associated with sperm competition, such as timing between insemination and fertilization, female reproductive tract morphology, and fertilization environment. Also, males that adopt alternative mating tactics may face distinct sperm competition pressures, which may lead to the evolution of intraspecific diversity in ejaculates. In loliginid squids, males with alternative reproductive tactics (sneakers and consorts) differ not only in mating behavior, but also transfer spermatophores into two distinct sites within the female. Here, we compared structure and functioning of spermatophores between sneakers and consorts in the squid Doryteuthis plei applying microscopy techniques and in vitro experiments. Sneakers and consorts exhibit differences in spermatophore structure that lead to distinct spermatophoric reactions and spermatangium morphologies. Moreover, in sneakers, sperm release lasts longer and their sperm show an aggregative behavior not detected in consorts. Slow sperm release may be a strategy to guarantee longer sperm provision, given the wide interval between sneaker mating and egg release. For consorts, in turn, intense and quick sperm discharge may be advantageous, as timing between mating and egg-laying is relatively short. Within the complex squid mating system, factors such as (i) different fertilization sites and (ii) interval between mating and egg release may also influence sperm competition, and ultimately shape the evolution of divergent ejaculates between dimorphic males.

Report this publication

Statistics

Seen <100 times