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Insect development. VIII. Maturation and early development of unfertilized grasshopper eggs
Author(s) -
King Robert L.,
Slifer Eleanor H.
Publication year - 1934
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1050560309
Subject(s) - biology , grasshopper , polar body , meiosis , sperm , parthenogenesis , ploidy , cleavage (geology) , embryo , embryogenesis , andrology , metaphase , human fertilization , botany , microbiology and biotechnology , zoology , anatomy , oocyte , genetics , chromosome , ecology , medicine , paleontology , fracture (geology) , gene
Maturation and early cleavage in unfertilized Melanoplus differentialis eggs have been followed with material secured immediately before as well as after oviposition, and (1) fixed at once, or (2) held in an incubator at 25°C. and, subsequently, fixed at selected intervals. Eggs ready to be laid were all found in the metaphase of the first maturation division. The second polar body is given off (at 25°C.) within 5 to 7 hours after laying. Meiosis appears to be unaffected by the absence of the sperm nucleus and proceeds at the same rate as in fertilized eggs. No morphological differences could be found between the process here and in eggs from mated females. During early cleavage, or later, the diploid number of chromosomes may be restored in some (or perhaps all) cells of the embryo. Development begins in the greater number of these unfertilized eggs but is successfully completed in only a very few.