The green bug and its enemies; A study in insect parasitism
Samuel John Hunter
Paperback
(RareBooksClub.com, March 6, 2012)
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1909 Excerpt: ...the factor upon which the variation is based. CONCLUSIONS. Under conditions which obtained in the laboratory, the average length of life is, for Toxoptera graminum, 42.5 days; for Macrosiphum granaria, 41.5 days. The average age when reproduction begins is, for loxoptera graminum, 11.5 days; for Macrosiphum granaria, 12 days. The average reproduction period is, for Toxoptera graminum 27.1 days; for Macrosiphum granaria, 25.8 days. The average number of young is, for Toxoptera graminum, 59.8; for Macrosiphum granaria, 35.4. The usual number of moults is, for Toxoptera graminum, 4. PROGENY OF ONE INDIVIDUAL DURING THE SEASON. Now, considering the reproductive period of the average green bug, based on the foregoing experiments, to be twenty-five days, and that reproduction begins on the seventh day and that the average daily offspring is two, we endeavored to ascertain the probable number of offspring during the season; that is, from April 1 to October 1. Accordingly Miss Jessie Smith, a competent accountant, by aotual computation carefully performed, starting with a single female at seven days old, found that the progeny of this green bug, making no allowances for mishaps, would aggregate from month to month the following numbers of individuals: First month, April 15,794 Second month, May 107,314,398 Third month, June 731,186,744,814 In this time six generations are completed and twenty-three generations in all are begun. THE EFFECT ON WHEAT OF THE GREEN BUG, Toxoptera graminum, AS COMPARED WITH THE MORE COMMON GRAIN APHIS, Macrosiphum granaria. IB.--February 26 to March 11, 1908. February 26 twenty winged Toxoptera graminum and twenty winged Macrosiphum granaria were placed on wheat in separate breeding-cages. March 11 the loxoptera wheat was dead; the Macro...