Cross-insemination

That both self-insemination and cross-fertilisation can occur in the same worm has been demonstrated unequivocally by the elegant experiments of Nollen (599) with H. diminuta. He used sperm labelled with [3H]thymidine and transplanted worms back to rats either singly or in combinations of labelled and unlabelled worms. In eight single-worm transplants (Table 7.2), all worms inseminated themselves, as demonstrated by the presence of labelled sperm in the receptaculum. In mixed labelled and unlabelled worm transplants, the labelled worms cross-inseminated with 92% of the unlabelled worms present. 

As already pointed out above, cross-insemination has been demonstrated in H. diminuta (599). This result has been confirmed by the elegant... 

Reproductive processes of helminths are diverse. The adults are hermaphroditic (monoecious) or dioecious, requiring, in some cases, no fertilization, in others, self- or cross-fertilization in hermaphrodites or insemination of females by males. Reproduction by monoecious species is simplified since no mate finding is necessary. In those species where separated sexes exist, and in hermaphroditic species where cross-fertilization is preferred, various adaptations have increased the likelihood of worm pairing and mate finding in the host. 

In the early 1900 s, apiology researchers had perfected the technique of instrumental insemination of the queen bee. This method made it possible to control the breeding process and has allowed for dramatic advances in the crossing of bees. The practical outcome of this science for the beekeeper is a well-tempered and productive bee. 

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