SOCIAL ORGANIZATION WITHIN CLONES OF THE SEA ANEMONE ANTHOPLEURA ELEGANTISSIMA

Area of Science:

• Marine Biology
• Behavioral Ecology
• Evolutionary Biology

Background:

• The aggregating sea anemone Anthopleura elegantissima forms clonal groups.
• Contact between non-clonemates triggers intraspecific aggression, maintaining aggregation boundaries.
• Competition for space is significant due to stable environments and life history traits.

Purpose of the Study:

• To investigate the costs and adaptations of intraspecific aggression in Anthopleura elegantissima.
• To understand the role of individual anemones at interclonal borders.

Main Methods:

• Observational study of anemone aggregations in the field.
• Comparison of morphological and reproductive traits between border and mid-clone anemones.
• Assessment of fission rates in warrior anemones.

Main Results:

• Anemones at interclonal borders ('warriors') exhibit larger acrorhagi, reduced gonads, and smaller size compared to mid-clone individuals.
• Warrior anemones show no increased fission rate, suggesting energy is diverted from reproduction and growth.
• Individual responses to local conditions can indirectly benefit the clone.

Conclusions:

• Interclonal border defense in Anthopleura elegantissima incurs significant energetic costs on individual anemones.
• Specialized border individuals demonstrate a simple yet effective form of social organization driven by natural selection on the clone.
• This strategy balances group benefits with individual sacrifice for clonal survival.