Ovarian development and insulin-signaling pathways during reproductive differentiation in the queenless ponerine ant Diacamma sp.

Yasukazu Okada, Satoshi Miyazaki, Hitoshi Miyakawa, Asano Ishikawa, Kazuki Tsuji, Toru Miura

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

In many social hymenopteran species, workers possess functional ovaries that are physiologically inactive in the presence of queens. We investigated the ovarian regulatory mechanism of workers and reproductives in a queenless ponerine ant, Diacamma sp., using histological and molecular techniques. In this ant, clear reproductive differentiation occurs via a highly sophisticated dominance behavioral interaction called "gemmae mutilation". This clear and rapid bifurcation of reproductive physiology allows us to elucidate the detailed ovarian differentiation process. Histological characteristics of functional ovaries (fusomes and ring canals) were found in both workers and reproductives, suggesting that early oogenesis is not blocked in workers. Since insulin/insulin-like growth factor signaling (IIS) is known to control insect reproduction, orthologs of 2 positive IIS regulators, insulin receptor and serine-threonine kinase Akt (protein kinase B), were cloned in Diacamma (DiaInR, DiaAkt); their expression patterns during reproductive differentiation were examined by real-time quantitative polymerase chain reaction; DiaInR and DiaAkt were strongly expressed in the gasters of reproductives. Whole-mount in situ hybridization of ovaries indicated that DiaInR and DiaAkt were expressed in nurse cells, oocytes, and upper germarial regions of reproductives but not of workers. Our data suggest that the IIS pathway accounts for reproductive differentiation in late oogenesis.

Original languageEnglish
Pages (from-to)288-295
Number of pages8
JournalJournal of Insect Physiology
Volume56
Issue number3
DOIs
Publication statusPublished - 2010 Mar 1
Externally publishedYes

Keywords

  • Insulin signaling
  • Ovary
  • Ponerine ant
  • Reproductive division of labor

ASJC Scopus subject areas

  • Physiology
  • Insect Science

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