Although it seems that males are an essential part of reproduction, there are some species that do just fine without them. It is possible for some aphids, crayfish, and komodo dragons to produce offspring from unfertilized eggs. Now, researchers from the University of Sydney have discovered yet another species that is able to flourish without the male variety.
The species in question is the termite Glyptotermes nakajimai. They live in forests and usually form colonies led by a queen and king. The king mates with the female for life (crazily, a female termite can live 30-50 years).
Two queens leading an all-female colony. Credit: University of Sydney
The researchers found six termite populations in Japan that were comprised of only asexual females. To further confirm their suspicions, the researchers found only unfertilized eggs and a lack of sperm in the queens’ sperm storage organs. The unfertilized eggs hatched as successfully as fertilized eggs in mixed sex populations. Occasionally, unfertilized eggs can also develop in mixed sex colonies, which can explain how these populations were able to evolve. These Japanese populations mutated from the sexual populations to produce only unfertilized eggs about 14 million years ago.
“These results demonstrate males are not essential for the maintenance of animal societies in which they previously played an active social role,” said Professor Nathan Lo from the University of Sydney’s School of Life and Environmental Sciences.
It appears that the male-less termites have an edge on their sexually reproducing counterparts. Because there is no fertilization and only females, the male-less termites are able to reproduce twice as fast. The all-female colonies also had a lower proportion of soldiers with more uniform head sizes, which may indicate this method is more effective. This fast growth rate and soldier effectiveness could make it easier for these populations to expand and conquer new environments.
You may wonder how reproduction can work without males (and why we have them). It is actually a question that has puzzled biologists for ages. Non-sexual reproduction is basically like producing a genetically identical clone, which means that if there is some sort of new environmental stressor, these species may not be able to adapt quickly enough, which could lead to inbreeding problems. These termites are flourishing now, but they might be in trouble later on.
Journal reference: Toshihisa Yashiro, Nathan Lo, Kazuya Kobayashi, Tomonari Nozaki, Taro Fuchikawa, Nobuaki Mizumoto, Yusuke Namba, Kenji Matsuura. Loss of males from mixed-sex societies in termites. BMC Biology, 2018; 16 (1) DOI: 10.1186/s12915-018-0563-y
