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THE INTERSTITIAL AND SPERMATOGENETIC TISSUE OF AUTUMN MIGRANTS IN SOUTHERN ENGLAND.
Author(s) -
Marshall B. Lofts A. J.
Publication year - 1957
Publication title -
ibis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 80
eISSN - 1474-919X
pISSN - 0019-1019
DOI - 10.1111/j.1474-919x.1957.tb03055.x
Subject(s) - reproduction , biology , zoology , seasonal breeder , juvenile , ecology
Summary. 1. Of 17 adult males of nine species of southbound migrants that were accidentally killed at about the point of departure from Southern Britain in autumn, all possessed an interetitium in the process of post‐nuptial rehabilitation (involving cholesterol production) even though they were flying away from the traditional breeding ground. Varying amounts of cholesterol‐positive material still lingered in the tubules. 2. Of 11 juvenile males of seven species similarly collected only six individuals possessed an interatitium in which had already developed cholesterol. One adult Redwing showed pronounced signs of autumnal sexuality in the production of a few primary spermatocytes. 3. Cholesterol is almost certainly the precursor of the steroid hormones; and its early conversion into androgens in “stationary” species is probably responsible for the widespread autumnal sexual behaviour that occasionally culminates in “out‐of‐season” reproduction. Its presence in adult migrants probably explains the recrudescence in sexual behaviour that occurs in certain species just before their departure from the breeding grounds. In migrants, however, unlike “stationary” species, this capacity to display is extinguished by the more powerful (in them) inherent urge to migrate. 4. Southbound, as well as northbound, migrants possess subcutaneous and subperitoneal fat‐deposits. The physiological basis for the production of this material is discussed briefly, and a possible additional function for such fat is mentioned.