The Effect of Environment On Sex Determination in Heterodera Rostochiensis

The conditions to which larvae of H. rostochiensis were exposed in host-plant roots determined the sex ratio of the adults. Apparently only second-stage larvae with giant cells of a sufficient size and nutrient content can become females. As the density of invading larvae increases progressively fewer find a site capable of containing such a giant cell and an increasing proportion become males. Most larvae that invade lateral roots become males.