THE AMPHIBIA OF OKLAHOMA 



these (Acris crepitans, Ps. triseriata, R. berlandicri, B. lu. woodhousii) breed- 

 ing behavior is initiated by rainfall at times; at other times, however, by 

 internal factors not too well understood, although probably wholly or par- 

 tially hormonal in nature (see Rugh, 1935, 1937, 1937a). B. w. woodhousii 

 and R. berlandieri are puzzling in this regard, for some individuals of both 

 will breed from early to mid-spring, irrespective of rainfall but others in the 

 same locality will await the rains of summer or fall. The common leopard 

 frog of Oklahoma has been known to breed in every month from February 

 to September inclusive; and in January, 1942, I found tadpoles of this species 

 which had survived the winter and which must have come from eggs laid 

 after rains the previous October or November. In February, 1946, tadpoles 

 were found which canie from a breeding congress observed the previous 

 September. Tadpoles also over-wintered near Norman, Oklahoma, during 

 the dry winter of 1946-47. The breeding pattern of R. berlandieri is so radi- 

 cally different from that of the mesically adapted R. p. pipiens Schreber of 

 the eastern portion of the United States that I have consistently maintained 

 that it must be taxonomically distinct from the eastern forms.'* R. p. pipiens 

 as I have observed it in Maine, New Hampshire, Massachusetts, Maryland, 

 New York, Michigan, Wisconsin, and northeastern New Mexico has a dis- 

 tinct breeding season whose early limit is modified by temperature (I have 

 found eggs in February in Maryland whereas in Maine breeding usually 

 does not begin until early April). By about May 15 in the East all breeding 

 has ceased, the breeding season has closed, and even torrential rains in June, 

 July, or August have no effect in stimulating further breeding (cf. Wright, 

 1920, and Wright and Wright, 1933, 1942). 



Noble and Aronson (1942), in a valuable experimental study on the 

 breeding behavior of the leopard frog of Vermont (presumably, R. pipiens 

 Sch.) show that initiation of breeding behavior in this species involves ovu- 

 lation under stimulation of the anterior pituitary hormones followed by a re- 

 ceptivity of the female to the male. They deduce from their laboratory study 

 that, in nature, both male and female are simultaneously stimulated by a 

 complex of environmental conditions at the proper time in the seasonal 

 rhythm, that ovulation then ensues, and clasping and egg laying follow. They 

 lay stress on this sequence of events and apparently think that their results 

 are in conflict with some of my own interpretations (Bragg, 194 Id). They 

 say, "Bragg believed that rain and other environmental conditions during 

 the proper season stimulate the pituitary. The sexually excited male, Bragg 

 said, now clasps the female; amplexus in turn stimulates the female pituitary 



•* This form would be A', hrachycephala according to Kauffelt (1937). Whether 

 brachycephala is distinct from pipiens or not has no bearing on the question here discussed 

 because both are mesically adapted forms essentially alike in breeding patterns. The Okla- 

 homa frog has recently been referred to R. pipiens bcrlandicn Baird by Mittlcman and 

 Gier (1942), but Moore, (1946) still insists that it is R. pipiens ScJireber, which he thinks 

 to have indistinct ecological variants in various positions of ts very wide range. So far as 

 technical naming is concerned, he may be correct. I am certain that the forms in Oklahoma 

 differ in habit patterns from their eastern and northern counterparts. I here follow Mittlc- 

 man and Gier in part. 



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