This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Scharrer, B. Search for Related Content PubMed PubMed Citation Articles by Scharrer, B.

Insect Tumors Induced by Nerve Severance: Incidence and Mortality^*

( Department of Anatomy, University of Colorado, School of Medicine, Denver, Colo.)

1. In the insect Leucophaea maderae the incidence of tumors developing after severance of the recurrent nerve is high—i.e., roughly 75 per cent. The incidence does not seem to differ significantly in males and females. Accordingly, castrates respond to the nerve transection in approximately the same way as noncastrate animals. Among the organs involved tumors appear most frequently in the midgut (stomach), an observation which may perhaps be explained by a more rapid and more destructive growth pattern of these as compared to tumors in other sites (salivary organs, foregut).

2. The mortality rates of tumor-bearing animals differ significantly: males as a group survive longer than females. The sex difference in resistance to the presence of tumors disappears after castration. This observation offers indirect evidence, but no proof, for the presence of sex hormones in insects.

^* Research grants from the American Cancer Society and The Anna Fuller Fund are gratefully acknowledged.

Received 9/29/52.