| Concept/Content |
reciprocity / black hamlet (Hypoplectrus nigricans) |
| Information caption |
Reciprocity can occur at various levels of costs and consequences. Among black hamlet fish of the Carribean (Hypoplectrus nigricans), the exchange involves reproduction. The fish are hermaphroditic; they can both spawn and fertilize. The energy investment in eggs is much greater than in sperm, however, so the reproductive cost to the fish that lays eggs is greater. What fosters reciprocity? Here, any laying of eggs is limited, and successive matings depend on the alternation of male and female roles (Krebs and Davies 1993, p. 285). Here, as elsewhere, repeated encounters allow reciprocity. |
| Inquiry caption |
Among black hamlet fish of the Carribean (Hypoplectrus nigricans), the potential exchange involves reproduction. The fish are hermaphroditic. They can both spawn and fertilize. The energy investment in eggs is much greater than in sperm, however, so the reproductive cost to the fish that lays eggs is greater. What strategy would you recommend to a black hamlet to ensure reproductive reciprocity with an unknown individual encountered on the reef? That is, how might you guard against a cheater, and ensure that the other individual fulfills its end of the "bargain"?
[For black hamlets, any initial laying of eggs is limited. Successive matings depend on the alternation of male and female roles (Krebs and Davies 1993, p. 285). Here, as elsewhere, repeated encounters allow reciprocity.]
Arrangements of reciprocity are indeed fragile and susceptible to cheaters. Such relationships have been modeled using computers for repeated encounters among individuals using various postures of cooperating or "defecting." An individual that "reciprocates" by doing whatever the other individual has done (whether to cooperate or not) seems to be the most effective strategy (Axelrod 1984).
Target Concept: Some cases of costly helping are explained by reciprocity. |
| Photographer |
Florent Charpin |
| Credit |
Coutesy of Florent Charpin, reefguide.com |
| SIZE in pixels [file size] |
600x448 |
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