Evidence for a Daily Rhythm of Heat Resistance in the Cricket Frog, Acris crepitans

Copeia ◽  
1969 ◽  
Vol 1969 (4) ◽  
pp. 852 ◽  
Author(s):  
Donald G. Dunlap
2013 ◽  
Vol 25 (1) ◽  
pp. 232 ◽  
Author(s):  
W. E. Snyder ◽  
V. L. Trudeau ◽  
N. M. Loskutoff

The World Conservation Union (IUCN) currently recognises Eleutherodactylus locustus from Puerto Rico and Plectrohyla acanthodes from Mexico and Guatemala as critically endangered, and they are recommended for ex situ breeding by several amphibian conservation organizations (e.g. AZA, ATAG, RCP, and AARK). Because of their very small and delicate bodies, conventional injectable methods developed for hormonally stimulating spawning in larger frogs and toads are undesirable, because this can result in trauma and injury. Recently, a protocol was developed for inducing spawning in frogs by co-injection of a gonadotropin-releasing hormone agonist (GnRHa) with metoclopramide-HCl (MET), a dopamine antagonist (Amphiplex; Trudeau et al. 2010 Rep. Biol. Endo. 8, 36). The goal of this study, therefore, was to determine the effectiveness of Amphiplex using 3 routes of exogenous treatments: (1) direct IP injection (0.4 µg of GnRHa + 10 µg of MET per gram of body weight), (2) injection into prey (1 µg of GnRHa + 25 µg of MET per insect) before feeding, and (3) a 60-min immersion in 10 mL of pond water containing 0.17 µg of GnRHa + 0.42 µg of MET per microliter. The northern cricket frog (Acris crepitans), a very common local species, was used as a model because it is also small, delicate, and difficult to handle. A total of 110 cricket frogs were caught locally either late or after their normal breeding season, sexed as males or females, and segregated into a control group that was housed similarly ex situ but not exposed to Amphiplex and the 3 Amphiplex experimental groups. The frogs were monitored daily for egg production and behavioural amplexus (potential spermiation). The results are summarised as follows (Table 1): of the frogs exposed to the Amphiplex-supplemented pond water, 84% of 38 females deposited eggs, and 6 pairs were observed in amplexus (indicating spermiation). Approximately 27% of more than 2242 eggs were found to develop cleavage divisions, and tadpoles were first observed in vitro after 4 days. In conclusion, to our knowledge this is the first report indicating that transdermal absorption of a reproductive hormone cocktail (e.g. Amphiplex) may serve in the application of assisted reproductive technology to increase the populations of critically endangered amphibians such as frogs and toads that may be too small or delicate for conventional methods of exogenous hormone treatments that require handling and injections. Table 1.Treated northern cricket frogs


1999 ◽  
Vol 77 (8) ◽  
pp. 1240-1246 ◽  
Author(s):  
Jason T. Irwin ◽  
Jon P. Costanzo ◽  
Richard E. Lee, Jr.
Keyword(s):  

1984 ◽  
Vol 5 (2) ◽  
pp. 101-107 ◽  
Author(s):  
Robert H. Gray

A three year field study was conducted to investigate the adaptive significance of color polymorphism in the cricket frog, Acris crepitans, in Illinois, U. S. A. Effective population breeding sizes were determined at seven different locations. Population characteristics in Illinois were compared with those from Texas. The three color morphs appear to be of equal survival value for cricket frogs in Illinois. Although strong selection may occur in Texas, small effective breeding sizes suggest that chance plays a major role in determining color morph frequencies in Illinois.


1995 ◽  
Vol 6 (2) ◽  
pp. 124-131 ◽  
Author(s):  
Michael J. Ryan ◽  
Karen M. Warkentin ◽  
Blinda E. McClelland ◽  
Walter Wilczynski

Zootaxa ◽  
2006 ◽  
Vol 1104 (1) ◽  
pp. 1 ◽  
Author(s):  
MALCOLM L. McCALLUM ◽  
STANLEY E. TRAUTH

We investigated the validity and distribution of the subspecies Acris crepitans blanchardi.  Currently Acris crepitans contains three subspecies: the northern cricket frog (A. c. crepitans), Blanchards cricket frog (A. c. blanchardi) and the coastal cricket frog (A. c. paludicola).  We examined the diagnostic characters of 1441 specimens from the center of the range (Arkansas, Missouri, and Mississippi), 161 specimens from the extreme northwest portion of this species range (South Dakota and Nebraska), and 85 from the extreme southeast portion of the species range (Florida and Georgia).  Discriminate analysis was applied to the tabulated data and no significant differences between portions of the range could be discerned.  No concrete evidence was found to support designation of specimens from South Dakota and Nebraska or from Smallens Cave (origin of the type specimen) as A. c. blanchardi.  This information places the subspecies A. c. blanchardi in a status of doubtful validity suggesting that no delineation between A. c. blanchardi and A. c. crepitans should be made at this time.


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