Novel use of ink by territorial males in the coastal squid Heterololigo bleekeri
Data files
Sep 15, 2026 version files 32.01 KB
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Data1_Hosono_et_al..csv
21.78 KB
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Data2_Hosono_et_al..csv
6.16 KB
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README.md
4.08 KB
Abstract
We report that territorial males of the Japanese spear squid Heterololigo bleekeri use their ink in contexts other than antipredator defense, for which it is commonly used. Territorial males released highly diffusive ink both toward males and females and in the absence of a specific target individual. These inkings were performed in a consistent behavioral pattern. In some cases, territorial males released ink multiple times in rapid succession, with successive inkings occurring within 2.0 s as part of a single behavioral sequence. However, morphological adaptations to these territorial inking behaviors could not be detected. The ink used in this context may function as a chemical signal, analogous to scent marking, advertising the territorial male’s competitiveness to rival males and attractiveness to females.
Dataset DOI: 10.5061/dryad.kprr4xhkw
Description of the data and file structure
The behavioral experiments were conducted in an experimental tank with seven squid (five males and two females) and one spawning substrate, and their behaviors were recorded using three fixed cameras. Three trials (A, B, and C) were conducted, during which a total of 158 inking events were observed. Data1 contains information on these inking events, including the behavioral context and mantle tip orientation around each inking event. Data2 contains morphological measurements used to compare ink sac weight among consort males, sneaker males, and mature females.
Files and variables
File: Data1_Hosono_et_al..csv
Description: The dataset (csv) contains Inking event ID, Trial, Time, Actor, Rapid shot, Approacher, Target sex, Inking location, Light condition, and Tip orientation ±2s. The Approacher, Target sex, and Tip orientation fields are left blank when Actor = “Non-territorial male” or Rapid_shot = “Y”. In addition, the Target sex field is left blank when Approacher = “No Approach”. Furthermore, the data at −2 s and −1.5 s were not available for inking events C30 and C38.
Variables
- Inking event ID: A1–44, B1–66, and C1–48
- Trial: Trial A, Trial B, and Trial C
- Time: Date and time when the inking occurred (YYYY-MM-DD HH:MM format).
- Actor: Individual that performed the inking behavior. "Territorial male" and "Non-territorial male"
- Rapid shot: Whether the inking was a rapid shot. “Y” indicates a successive inking that occurred within 2.0 s of the preceding inking as part of a single behavioral sequence, and “N” indicates otherwise.
- Approacher: Individual that approached prior to the inking event. "Territorial male", "Non-territorial male", or "No Approach". This field is left blank when the actor is "Non-territorial male" or when Rapid_shot = "Y".
- Target sex: Sex of the individual toward which the ink was directed when the Approacher was "Territorial male": "Male", "Female", or "Unknown"
- Inking location: "Spawning substrate side" or "Opposite side"
- Light condition: "bright" or "dark"
- Tip orientation -2s: Orientation of the mantle tip 2 s before the inking event. "Up", "Horizontal" or "Down"
- Tip orientation -1.5s: Orientation of the mantle tip 1.5 s before the inking event. "Up", "Horizontal" or "Down"
- Tip orientation -1s: Orientation of the mantle tip 1 s before the inking event. "Up", "Horizontal" or "Down"
- Tip orientation -0.5s: Orientation of the mantle tip 0.5 s before the inking event. "Up", "Horizontal" or "Down"
- Tip orientation 0s: Orientation of the mantle tip at the inking event. "Up", "Horizontal" or "Down"
- Tip orientation 0.5s: Orientation of the mantle tip 0.5 s after the inking event. "Up", "Horizontal" or "Down"
- Tip orientation 1s: Orientation of the mantle tip 1 s after the inking event. "Up", "Horizontal" or "Down"
- Tip orientation 1.5s: Orientation of the mantle tip 1.5 s after the inking event. "Up", "Horizontal" or "Down"
- Tip orientation 2s: Orientation of the mantle tip 2 s after the inking event. "Up", "Horizontal" or "Down"
File: Data2_Hosono_et_al..csv
Description: The dataset (csv) contains sample ID, Mantle Length (mm), Body Weight (g), Ink Sac Weight (mg), Sex, and Male Tactic. Body Weight was not measured for sample 240130-48F and is therefore left blank.
Variables
- ID: sample ID
- Mantle Length (mm): Mantle length of the individual in millimeters.
- Body Weight (g): Body weight of the individual in grams.
- Ink Sac Weight (mg): Ink sac weight of the individual in milligrams.
- Sex: "Male" or "Female"
- Male Tactic: "Consort" or "Sneaker". This field is left blank when the sex of the individual is female.
Access information
If you need further information, please contact corresponding author Shota Hosono.