Life History, Abundance, Activity, and Special Behaviors
This species is largely nocturnal and secretive, and during the summer rainy season can be found hidden under surface objects. It usually occupies an underground burrow that it digs in the soft earth with its hind feet, like other spadefoots in New Mexico. The hind feet are equipped with keratinized, sharp-edged spades. It is often seen on roadways during the night, in search of breeding sites or prey. S. multiplicata may secrete a musty skin toxin when it is molested. The toxin smells like raw peanuts and can irritate the sensitive membranes of the eyes and nose of those who rub their face after handling a spadefoot (Degenhardt et al. 1996).
S. multiplicata breeding, like that of other spadefoots, is closely associated with the summer monsoon rains that fill playa lakes and cause the rapid formation of pools in low-lying areas. The low frequency sound and vibration of rainfall or thunder are the primary cues for emergence. Average breeding period duration is only about 1.6 days. Males usually call while they are floating on the surface of the water. Eggs are fertilized by the male as they are laid during amplexus. There is a high level of variation in clutch size within breeding aggregations, but an adult female lays about 1,070 eggs on average. Eggs are deposited in cylindrical masses that are attached to submerged aquatic vegetation or debris. They hatch in as little as 42-48 hours. The tadpoles metamorphosize in about three weeks, and toadlets emerge from the drying pond and disperse (Degenhardt et al. 1996).
S. multiplicata is a generalized arthropod predator that concentrates on ground dwelling species, as do most spadefoots. Beetles, orthopterans, ants, spiders, and termites comprise over 90% of their total diet, with no major differences in diet by sex or season. Arthropods with well known chemical defenses, such as blister beetles, velvet ants, stink bugs, and millipedes, are usually avoided by S. multiplicata, but it will occasionally feed on centipedes and scorpions. Studies have shown that S. multiplicata may require seven feedings before it has accumulated the fat reserves required to survive for 12 months (Degenhardt et al. 1996).
The call is a vibrant, metallic trill that sounds like running a fingernail along the stiff teeth of a comb. Each of these trills is about 0.75 - 1.5 seconds long (Conant and Collins 1991).
- Conant, R. and Collins, J. T. (1991). A Field Guide to Reptiles and Amphibians: Eastern/Central North America. Houghton Mifflin, Boston.
- Degenhardt, W.G., Painter, C.W., and Price, A.H. (1996). Amphibians and Reptiles of New Mexico. University of New Mexico Press, Albuquerque.
- Brown, H. A. (1976). ''The status of California and Arizona populations of the Western Spadefoot Toads (genus Scaphiopus).'' Los Angeles County Museum of Natural History, Contributions in Science, 286, 1-15.
- Sattler, P.W. (1980). ''Genetic relationships among selected species of North American Scaphiopus.'' Copeia, 1980(4), 605-610.
- Simovich, M. A. (1994). ''The dynamics of a spadefoot toad (Spea multiplicata and S. bombifrons) hybridization system.'' Herpetology of North American Deserts. P. R. Brown and J. W. Wright, eds., Special Publication No. 5, Southwestern Herpetologists Society, Los Angeles.
- Smith, H. M. (1978). A Guide to Field Identification: Amphibians of North America. Golden Press, New York.
- Stebbins, R. C. (1962). Amphibians of Western North America. University of California Press, Berkeley.
- Tanner, W. W. (1989). ''Status of Spea stagnalis Cope (1875), Spea intermontanus Cope (1889), and a systematic review of Spea hammondii Baird (1839) (Amphibia: Anura).'' Great Basin Naturalist, 49, 503-510.
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