Some expecting mothers may hope for a boy, while others hope for a girl, and many others have no preference. No matter which sex their baby turns out to be, mothers are generally happy to have a baby in their lives. However, that does not mean that mothers don’t secretly wish to have the same ability that beetle mothers get to enjoy. As you can already assume, female beetles have the ability to determine the sex of their offspring. As it turns out, this ability contributes to the overall health of the species.
Some female beetles possess manly features, while other females possess entirely feminine features. Not surprisingly, female beetles that possess masculine features carry more genes that are associated with masculine features. Female beetles that possess feminine features also must be carrying an abundance of genes that are associated with feminine features. The females with masculine features must have inherited these features from a strong and reproductively successful father. Masculine beetle features that are considered strong and reproductively beneficial include large jaws and flexible bodies that can be easily maneuvered during aggressive male-on-male conflicts. Females that possess masculine features are clearly better suited for producing males than females. Females with masculine features do not reproduce as many offspring as feminine-looking beetles. Masculine females possess slim bodies that are not well suited for reproduction, and feminine-looking males do not possess the large jaws that are needed to win fights with other males.
Before a male beetle mates, they first fight other beetles in order to win a female. The last male beetle standing gets to pass on its genes, but they cannot win unless they possess the largest jaws. Therefore, male beetles with effeminate small jaws will not live to pass on their genes, and this is not good for the species. This is why masculine female beetles have evolved the ability to produce more sons than daughters if necessary. This way, a masculine female does not have to waste its male genes on female offspring who would not be reproductively successful with male features anyway. The ability to determine the sex of their offspring also ensures that only the most fit male and female beetles are being added to the beetle population. Without this ability, beetle offspring would become progressively less fit for reproduction with each successive generation. Researchers are not yet sure how females are able to alter the sex of their offspring, but a physiological mechanism in female beetles that allows for hormone manipulation may be responsible.
Do you think that it is likely that other insect species also possess the ability to alter the sex of their offspring in order to benefit the health of the overall beetle population?