Ontogenetic shifts in fusion-rejection thresholds in a colonial marine hydrozoan, Hydractinia symbiolongicarpus

Alexandra Wilson, Richard K. Grosberg

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Like many modular organisms, genetically distinct colonies of the hydrozoan Hydractinia symbiolongicarpus naturally fuse to produce chimeras. One of the principal cooperative benefits of fusion arises from the increased size of the resulting chimeric individual, which may enhance survivorship. However, fusion also promotes conflict through competition between cell lineages for representation in reproductive tissues. Previous studies on H. symbiologicarpus show that, consistent with kin selection theory, a highly polymorphic self/non-self recognition system limits fusion to close kin. However, these recognition systems are intrinsically subject to error. Conspecific acceptance threshold theory predicts that as the costs and benefits of making recognition errors change, or the frequencies of encounters between acceptable and unacceptable kin vary, the recognition system should respond. Specifically, as the benefits of acceptance decline or the frequency of encounters with unacceptable individuals increases, the acceptance threshold should become more restrictive. We tested this hypothesis by monitoring changes in the expression of fusion/rejection behaviors of H. symbiolongicarpus during colony establishment, a period of high mortality when the size-dependent benefits of fusion may be changing most rapidly, and the frequency of encounters with close kin declines. Across seven full-sib families, fusion frequencies between pairs of sibling colonies declined from 73% for 3-day-old colonies to 58% by day 12. This decline is consistent with optimal acceptance threshold theory. However, the period of maximum decline also corresponds to an interval during which the recognition effector mechanism becomes fully functional, suggesting that the shift to a more restrictive conspecific acceptance threshold may reflect an intrinsic constraint on recognition system maturation.

Original languageEnglish
Pages (from-to)40-49
Number of pages10
JournalBehavioral Ecology and Sociobiology
Volume57
Issue number1
DOIs
StatePublished - Nov 1 2004
Externally publishedYes

Fingerprint

Cell Lineage
Cost-Benefit Analysis
Survival Rate
Mortality
kin recognition
kin selection
chimerism
cooperatives
chimera
survival rate
survivorship
monitoring
maturation
organisms
mortality
cells
cost

Keywords

  • Chimera
  • Conspecific acceptance threshold
  • Germline parasitism
  • Kin recognition
  • Self/non-self recognition

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Ecology
  • Behavioral Neuroscience

Cite this

Ontogenetic shifts in fusion-rejection thresholds in a colonial marine hydrozoan, Hydractinia symbiolongicarpus. / Wilson, Alexandra; Grosberg, Richard K.

In: Behavioral Ecology and Sociobiology, Vol. 57, No. 1, 01.11.2004, p. 40-49.

Research output: Contribution to journalArticle

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