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Quantitative Matching of Clutch Size in Reciprocating Hermaphroditic Worms
Laura Picchi1, Guénaël Cabanes2, Claire Ricci-Bonot1
1LEEC - Laboratoire d'Ethologie Expérimentale et Comparée, Université Paris 13, Sorbonne Paris Cité, 99 avenue J.-B. Clément, 93430 Villetaneuse, France.
Current Biology : CB
|October 16, 2018
Summary
Cooperation in marine worms Ophryotrocha diadema demonstrates conditional reciprocity, where individuals adjust egg exchange based on partner behavior. This suggests sophisticated cooperation strategies can evolve in animals with limited cognitive abilities.
Area of Science:
- Evolutionary biology
- Animal behavior
- Marine biology
Background:
- Reciprocity is a controversial explanation for cooperation among non-kin.
- The capacity to adjust cooperation based on received aid is key to resolving this debate.
- Marine polychaete worms (Ophryotrocha diadema) are ideal models due to their mating system and external fertilization.
Purpose of the Study:
- To test if Ophryotrocha diadema exhibit conditional reciprocity in egg exchange.
- To determine if sexual role alternation is driven by conditional rather than by-product reciprocity.
- To investigate if cooperation strategies in O. diadema are cognitively sophisticated.
Main Methods:
- Observational studies of Ophryotrocha diadema mating behavior.
- Analysis of egg clutch size and exchange patterns between partners.
- Comparison of fitness returns for reciprocating versus non-reciprocating strategies.
Main Results:
- Ophryotrocha diadema worms reciprocate eggs conditionally based on partner actions.
- Cooperation quality is adjusted according to the partner's previous behavior.
- Egg reciprocation provides equivalent fitness benefits through both female and male reproductive functions.
Conclusions:
- Conditional reciprocity, involving fine-tuned adjustments to cooperation, is present in cognitively unsophisticated animals.
- These findings broaden the understanding of conditional reciprocity in the animal kingdom.
- O. diadema's behavior challenges assumptions about the cognitive requirements for complex cooperation.
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