Intergenerational genotypic interactions drive collective behavioural cycles in a social insect

Area of Science:

• Animal behavior
• Ecology
• Genetics

Background:

• Social animals exhibit collective activity cycles, exemplified by army ant colony cycles.
• These cycles are synchronized behavioral oscillations among group members, lasting about a month.
• The regulation of army ant colony cycle duration is poorly understood, despite its link to brood development.

Purpose of the Study:

• To investigate the regulation of army ant colony cycle duration.
• To identify the sources and impacts of variation in cycle length.
• To explore interactions between brood and workers in clonal raider ants.

Main Methods:

• Long-term monitoring of clonal lineages to establish cycle length variation.
• Cross-fostering experiments with four lineages.
• Developmental, morphological, and automated behavioral tracking analyses.

Main Results:

• Cycle length variation is linked to the duration of the larval developmental stage.
• Both brood lineage (direct genetic effects) and worker lineage (indirect genetic effects) influence larval stage duration.
• Worker lineage affects brood adult size, and brood lineage influences worker behavior (walking speed, time in nest).

Conclusions:

• Colony cycle duration in clonal raider ants is regulated by genetic effects from both brood and workers.
• Indirect genetic effects play a significant role in modulating colony cycle dynamics.
• Brood-to-worker genetic effects on behavior highlight complex interactions within ant colonies.