On intersexuality in the crayfish Cherax quadricarinatus: An inducible sexual plasticity model

Amir Sagi, Rivka Manor, Carmen Segall, Claytus Davis, Isam Khalaila

Research output: Contribution to journalArticlepeer-review

51 Scopus citations


Sexual differentiation is a plastic process. The plasticity may be manifested during embryo-genesis, when one set of primordial reproductive ducts develops while the other degenerates. In adults, many normal (e.g., sequential hermaphroditism) and abnormal (e.g., endocrine disorders or exposure to endocrine disruptors such as estrogenic pollutants) cases are known in which sexual plasticity may be expressed as various degrees of feminization. In crustaceans, the androgenic gland (AG) regulates the development of male characteristics; its absence results in feminization, often including the onset of vitellogenesis. A unique model of intersexuality was found in the crayfish Cherax quadricarinatus, in which some degree of natural sexual plasticity is observed. Two to 14% of the population are intersex individuals, having both male and female genital openings. Intersex specimens always function as males but may also contain an ovary in a permanently arrested, pre-vitellogenic state. This sexual plasticity model was recently characterized and investigated with respect to the role of the AG and the onset of vitellogenesis. Removal of the AG in intersex individuals induced the reproductive system to shift from a permanently active male state to a female state. This shift included changes in morphology, cessation of spermatogenesis and onset of secondary vitellogenesis manifested by a change in the ovarian protein profile, translocation of protein kinase C (PKC) in the ovary and appearance of secondary vitellogenic high-density lipoprotein (HDL) in the hemolymph. The vitellogenin gene was found to be induced in the hepatopancreas of AG ablated intersex individuals suggesting that the AG represses transcription of this gene in intact intersex individuals. The experimentally inducible sex shift in the crayfish provides a unique and controlled model system for the study of sexual differentiation and plasticity at the physiological and molecular levels. The findings presented here also illustrate the central role of the AG in the regulation of sexual differentiation in sexually plastic as well as gonochoristic crustacean species.

Original languageEnglish
Pages (from-to)27-33
Number of pages7
JournalInvertebrate Reproduction and Development
Issue number1-3
StatePublished - 1 Jan 2002


  • Androgenic gland
  • Cherax quadricarinatus
  • Crayfish
  • Crustacea
  • Decapoda
  • Intersexuality
  • Sexual plasticity
  • Vitellogenesis

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Developmental Biology


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