Send to

Choose Destination
Proc Biol Sci. 2019 Nov 20;286(1915):20191677. doi: 10.1098/rspb.2019.1677. Epub 2019 Nov 20.

The inherited bacterial symbiont Hamiltonella influences the sex ratio of an insect host.

Author information

Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, People's Republic of China.
Department of Entomology, Cornell University, Ithaca, NY 14853, USA.
Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.


In many intracellular symbioses, the microbial symbionts provide nutrients advantageous to the host. However, the function of Hamiltonella defensa, a symbiotic bacterium localized in specialized host cells (bacteriocytes) of a whitefly Bemisia tabaci, is uncertain. We eliminate this bacterium from its whitefly host by two alternative methods: heat treatment and antibiotics. The sex ratio of the host progeny and subsequent generations of Hamiltonella-free females was skewed from 1 : 1 (male : female) to an excess of males, often exceeding a ratio of 20 : 1. B. tabaci is haplodiploid, with diploid females derived from fertilized eggs and haploid males from unfertilized eggs. The Hamiltonella status of the insect did not affect copulation frequency or sperm reserve in the spermathecae, indicating that the male-biased sex ratio is unlikely due to the limitation of sperm but likely to be associated with events subsequent to sperm transfer to the female insects, such as failure in fertilization. The host reproductive response to Hamiltonella elimination is consistent with two alternative processes: adaptive shift in sex allocation by females and a constitutive compensatory response of the insect to Hamiltonella-mediated manipulation. Our findings suggest that a bacteriocyte symbiont influences the reproductive output of female progeny in a haplodiploid insect.


endosymbiont; reproductive manipulation; sex allocation

[Available on 2020-11-20]

Supplemental Content

Full text links

Icon for Atypon
Loading ...
Support Center