Attempted Predation of Couch's Spadefoot (Scaphiopus couchii) Juveniles by Ants (Aphaenogaster cockerelli)

2001 ◽  
Vol 46 (1) ◽  
pp. 104 ◽  
Author(s):  
Kevin E. Bonine ◽  
Gage H. Dayton ◽  
Robin E. Jung
Keyword(s):  
Scaphiopus Couchii

Priority effects and desert anuran communities

2005 ◽  
Vol 83 (8) ◽  
pp. 1112-1116 ◽  
Author(s):  
G H Dayton ◽  
L A Fitzgerald
Keyword(s):  
Species Composition ◽  
Laboratory Experiments ◽  
Hatching Success ◽  
Aquatic Ecology ◽  
Priority Effects ◽  
Scaphiopus Couchii ◽  
Ephemeral Pools ◽  
Desert Regions ◽  
Community Assemblages ◽  
Current Paradigm

The roles of priority effects and predation in structuring anuran communities have not been considered important in desert environments characterized by highly ephemeral pools and anuran species that breed synchronously. Predation is one mechanism that can set the stage for priority effects to be important, especially in ephemeral pools where resources are limiting and densities are high. We observed oophagy by Scaphiopus couchii Baird, 1854 on eggs of Bufo speciosus Girard, 1854 in the field and conducted laboratory experiments to test the hypothesis that S. couchii tadpoles would reduce B. speciosus survivorship via predation. Three-day-old S. couchii tadpoles reduced hatching success of B. speciosus eggs by nearly 90%. When S. couchii and B. speciosus eggs were laid the same day, S. couchii tadpoles reduced B. speciosus egg survivorship by 56%. Our results indicate that priority effects and predation may play an important role in influencing species composition of anuran assemblages in desert regions. Our study provides more support for the need to reevaluate the current paradigm in aquatic ecology that suggests predation does not play a role in structuring community assemblages in highly ephemeral pools.

Size at Metamorphosis and Water Loss in a Desert Anuran (Scaphiopus couchii)

Copeia ◽  
1994 ◽  
Vol 1994 (2) ◽  
pp. 372 ◽  
Author(s):  
Robert A. Newman ◽  
Arthur E. Dunham
Keyword(s):  
Water Loss ◽  
Scaphiopus Couchii ◽  
Size At Metamorphosis

Reproductive Endocrinology of the Explosively Breeding Desert Spadefoot Toad,Scaphiopus couchii

1997 ◽  
Vol 105 (1) ◽  
pp. 102-113 ◽  
Author(s):  
Loreé A. Harvey ◽  
Catherine R. Propper ◽  
Sarah K. Woodley ◽  
Michael C. Moore
Keyword(s):  
Reproductive Endocrinology ◽  
Scaphiopus Couchii ◽  
Spadefoot Toad

Pathological effects of Pseudodiplorchis americanus (Monogenea: Polystomatidae) on the lung epithelium of its host, Scaphiopus couchii

Parasitology ◽  
2002 ◽  
Vol 125 (2) ◽  
pp. 143-153 ◽  
Author(s):  
R. C. TINSLEY ◽  
J. CABLE ◽  
R. PORTER
Keyword(s):  
Fibrous Tissue ◽  
Residual Effect ◽  
Blood Feeding ◽  
Scar Tissue ◽  
Lung Damage ◽  
Type I ◽  
Lung Epithelium ◽  
Past Infection ◽  
Scaphiopus Couchii ◽  
In The Wild

Infection of the desert toad, Scaphiopus couchii, by the monogenean Pseudodiplorchis americanus involves 2 principal sites: post-invasion juveniles reside in the respiratory tract for 1 month before migrating to the urinary bladder where they reach sexual maturity and may live up to 4 years. While previous work has demonstrated the long-term impact on host condition of the blood-feeding adults, this study assesses pathological effects of the short-term pulmonary infection. Lung ultrastructure was compared in toads (i) maintained in captivity for 1 year without invasion, and (ii) experimentally infected with 50–300 juveniles/host, equivalent to burdens in the wild, and examined 23–44 days p.i. Typically, the alveolar lining of S. couchii is composed of a single cell type with characteristics of both Type I and Type II pneumocytes. However, infected lung tissue exhibited an inflammatory reaction with epithelial cell vacuolation, interstitial oedema, and an increase of alveolar exudate, leucocytes and fibrous tissue. Accompanying a post-infection increase in host immune cells in the lungs, there was evidence of reciprocal tegumental damage to the parasites. Lung epithelium of toads free of infection for 1 year exhibited scar tissue representing a residual effect of past infection. The pathological consequences of P. americanus infection therefore have 2 components. Acute lung infection coincides with the host's brief activity season: impaired respiratory function could compromise feeding and accumulation of reserves and hence ability to survive following a 10 month period of hibernation. Additionally, adult toads are normally exposed annually to re-infection and may accumulate chronic lung damage with extended effects on host survival.

Survival of Pseudodiplorchis americanus (Monogenea) under controlled environmental conditions

Parasitology ◽  
1994 ◽  
Vol 108 (2) ◽  
pp. 185-194 ◽  
Author(s):  
K. Tocque ◽  
R. C. Tinsley
Keyword(s):  
Urinary Bladder ◽  
Significant Loss ◽  
Temperature Cycle ◽  
First Year ◽  
Temperature Dependent ◽  
Natural Conditions ◽  
Scaphiopus Couchii ◽  
Progressive Loss ◽  
Transmission Opportunity ◽  
Very High

SUMMARYPopulations of Pseudodiplorchis americanus infecting the desert toad, Scaphiopus couchii, have previously been shown to be remarkably stable from year to year, despite wide variation in conditions promoting invasion. The present study aimed to document the survival of both first-year and pre-existing adults under controlled laboratory temperatures. First-year worm survival in experimentally infected toads was shown to be very high for the first 5 months after migration to the definitive site, and there was no difference in survival at 25 °C or 15–20 °C. There was also no density-dependent survival during the same period: 20% of worms were recovered from the host urinary bladder, irrespective of initial intensities. After the first 5 months, there was a progressive loss of worms in toads maintained at 25 °C but not at 15–20 °C. Pre-existing adult populations were shown to be virtually identical to those under natural conditions for the first 4 months after toad capture. Following this, at 25 °C, populations declined and no pre-existing adults were recovered after 11–14 months. There was no such loss of pre-existing adults at 15–20 °C for up to 14 months. A diurnal temperature cycle of 20–34 °C (simulating temperatures during the desert summer) did not lead to a significant loss of worms. These observations suggest that during one annual cycle in the desert, when temperatures remain above 20 °C for less than 6 months, most adult worms established in the host urinary bladder will survive to the next transmission opportunity. However, the similar longevity of first-year and pre-existing adults in laboratory maintained toads shows that loss of worms cannot be due solely to parasite ageing. Temperature-dependent survival of P. americanus is suggestive of a host immune response. Low temperatures, which inhibit parasite growth and development, are essential for the survival of P. americanus.

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