Untangling loliginid squid alternative reproductive tactics by exploring long-term sperm storage and multiple spawning

• Grant number: 24/19926-5
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: February 01, 2025
• End date: July 31, 2025
• Field of knowledge: Biological Sciences - Zoology - Animal Behavior
• Principal Investigator: José Eduardo Amoroso Rodriguez Marian
• Grantee: Matheus Lima Silva Vieira
• Supervisor: Noritaka Hirohashi
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Shimane University, Japan
• Associated to the scholarship: 23/07751-3 - Spawning pattern of the squid Doryteuthis pleii (Blainville, 1823) (Mollusca: Cephalopoda), as a basis for understanding the species' mating system, BP.MS

Abstract

Cephalopods exhibit a great diversity of reproductive strategies, and understanding these traits is essential to comprehend the role of sexual selection in the diversification of the clade. Squids of the family Loliginidae are particularly interesting in this context, as they have a complex mating system, including male alternative reproductive tactics. Large males (consorts) and small males (sneakers) transfer spermatophores to different sites on the female's body: the oviduct opening and the buccal area, respectively. Although the consort site is more advantageous, the sneaker site contains a seminal receptacle capable of long-term sperm storage. Therefore, understanding how the female uses this reserve is essential to understand the reproductive success of sneakers. This research proposal aims to investigate the use of the sperm reserve in the seminal receptacle of Doryteuthis pleii females. To achieve this goal, we will: (1) develop SSR markers for the species based on shotgun genome sequencing; (2) determine the minimum number of males with sperm stored in the seminal receptacle; (3) assess how the female uses the stored sperm by comparing the patterns of multiple paternity between sequential egg masses of isolated captive females; (4) test whether the number of males with sperm stored in the seminal receptacle changes after spawning.