Worksheet 5

Survival Adaptation Parthenogenesis Fertile eggs without mating.

These amazing creatures have many tricks to increase their chance of survival. However, the ability of female stick insects to produce fertile eggs in the absence of a male is truly an incredible evolutionary achievement. It is known as parthenogenesis, which is Greek for virgin birth. This process, wonderful as it may be, has one small hiccup. You see, parthenogenesis produces insects of the same sex. Depending on the species the nymphs will be all female or all male. Often the nymphs are all female. Male insects are usually smaller, lighter and capable of flying from tree to tree. Females on the other hand are big, heavy and are bound to the one tree. Is it an advantage for parthenogenesis to produce all female insects rather than all male? Explain. Why is parthenogenesis an advantage? What other creatures can reproduce without fertilisation?