Science World curator Christine Olsen with Larry, a rare male stick insect born into an all-female colony. (Credit: Arlen Redekop) It’s a boy! Science World staffers were in disbelief after a male ...

While most animals reproduce sexually, some species rely solely on females for parthenogenetic reproduction. Even in these species, rare males occasionally appear. Whether these males retain ...

Among animals where sexual reproduction is common, there are quite a few species that reproduce only with females. In such species, females give birth to female offspring (this is called ...

Traits are often lost during evolution, either because they are no longer beneficial or because they are too costly to maintain. When this happens, it is generally believed that the genes underlying ...

Male (top) and female (bottom) Lord Howe Island stick insects from the captive-bred Ball's Pyramid population, also known as "tree lobsters," on a leaf at the Melbourne Zoo. Lord Howe Island Stick ...