Male-killing bacterium in a fifth ladybird beetle, Coleomegilla maculata (Coleoptera: Coccinellidae)

Gregory D.D. Hurst, Tansy C. Hammarton, John J. Obrycki, Tamsin M.O. Majerus, Linda E. Walker, Dominique Bertrand, Michael E.N. Majerus

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


Inherited symbionts which selectively cause the death of male hosts are found widely across the Insecta. Previous studies have shown a single, but different micro-organism to be responsible for male-killing in each taxonomic group studied. We here produce evidence that within a group of insects, the Coccinellidae, there is more than one causal agent of male lethality. We report a novel observation of a male-killing trait in the species Coleomegilla maculata. Six of 26 crosses were found to produce a female- biased sex ratio associated with a low egg hatch-rate. The trait was matrilinearly inherited and was observed to be tetracycline-sensitive. However, tests which indicate the presence of a Rickettsia, previously found to cause male-killing in another member of the Coccinellidae, Adalia bipunctata, proved negative. We therefore conclude that the phenomenon of male-killing is multicausal, within, as well as between, taxonomic groups of the Insecta.

Original languageEnglish
Pages (from-to)177-185
Number of pages9
Issue number2
StatePublished - Aug 1996

Bibliographical note

Funding Information:
Michael Ashburner for advice and loan of equip-ment, and Mr Alan Feast and Mr Roger Day for technical support. This work was carried out in a laboratory built with the support of the Wolfson Foundation. We wish to thank Christ's College, Cambridge (G. H.), the Weilcome Foundation and the Balfour Browne Fund (T. H.), and the NERC (grant GR 9/993 to M. M.) for financial support.


  • Coleomegilla maculata
  • female-biased sex ratio
  • inherited symbiont
  • male- killing

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)


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