Mothers modify eggs into shields to protect offspring from parasitism

Joseph B. Deas, Martha S. Hunter

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Eggs are an immobile, vulnerable stage of development and their success often depends on the oviposition decisions of the mother. Studies show that female animals, and sometimes males, may invest parental resources in order to increase the survival of their offspring. Here, we describe a unique form of parental investment in offspring survival. The seed beetle Mimosestes amicus may lay eggs singly, or may cover eggs with additional egg(s). This egg stacking serves to significantly reduce the mortality of the protected egg from parasitism by the parasitic wasp, Uscana semifumipennis. The smaller top eggs serve only as protective shields; they are inviable, and wasps that develop in them suffer negative fitness consequences. Further, we found egg stacking to be inducible; M. amicus increase the number of stacks they lay when parasitoids are present. However, stacking invokes a cost. When wasps are absent, beetles lay more single eggs, and produce more offspring, highlighting the adaptive value of this extraordinary example of behavioural plasticity in parental investment.

Original languageEnglish (US)
Pages (from-to)847-853
Number of pages7
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1730
StatePublished - 2012


  • Egg stacking
  • Life-history trade-offs
  • Mimosestes amicus
  • Offspring defence
  • Offspring quality versus quantity
  • Seed beetles

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology
  • General Immunology and Microbiology
  • General Environmental Science
  • General Agricultural and Biological Sciences


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