Maternal vibration: an important cue for embryo hatching in a subsocial shield bug

Area of Science:

• Behavioral Ecology
• Entomology
• Reproductive Biology

Background:

• Parental care around hatching is common across taxa, suggesting adaptive value for vulnerable young.
• The specific adaptive functions of hatching care, however, remain largely undefined.
• Subsocial insects provide a model for studying the evolution of complex parental behaviors.

Purpose of the Study:

• To investigate the function of maternal hatching care in the shield bug, Parastrachia japonensis.
• To determine if maternal behaviors regulate hatching synchrony and success.
• To differentiate between hatching assistance and hatching regulation as functions of maternal care.

Main Methods:

• Observed maternal egg-mass vibration and guarding behavior in P. japonensis.
• Compared hatching patterns and rates in control, mother-removed, and artificial vibration groups.
• Used intermittent artificial vibrations mimicking maternal patterns and continuous vibrations.

Main Results:

• P. japonensis mothers exhibit intermittent egg-mass vibration for extended periods (>6 hours).
• Synchronous hatching and high hatching rates occurred in control and intermittent artificial vibration groups.
• Asynchronous hatching and reduced hatching rates were observed in mother-removed and continuous vibration groups.

Conclusions:

• Maternal hatching care in P. japonensis primarily functions as hatching regulation, not direct assistance.
• Specific vibrational cues from the mother are crucial for inducing and synchronizing embryo hatching.
• Dependence on maternal cues may explain reduced hatching rates when care is absent.