Intraspecific variation in diet within and between trophic morphs in larval tiger salamanders (Ambystoma tigrinum nebulosum)

1984 ◽  
Vol 62 (2) ◽  
pp. 168-174 ◽  
Author(s):  
James P. Collins ◽  
Joseph R. Holomuzki
Keyword(s):  
Intraspecific Variation ◽  
Narrow Range ◽  
Ambystoma Tigrinum ◽  
Tiger Salamanders ◽  
Ambystoma Tigrinum Nebulosum

Larvae of Ambystoma tigrinum nebulosum are dimorphic. The "broad-headed" morph is cannibalistic and has a wider head and enlarged vomerine teeth compared with typical larvae. We collected larvae from tour habitats in Arizona, U.S.A., to quantify how diet varies within and betweeen morphs relative to habitat, and how diet varies relative to age in typical morphs from one habitat. Broad-headed or cannibalistic morphs occurred in both sexes and most of their diet [Formula: see text] was other salamanders. A variety of invertebrates comprised the remainder of their diet. Typical morphs ate primarily macroinvertebrates and plankton, and rarely (1 of 170 larvae analyzed) conspecifics. Young typical larvae consumed a narrow range of prey, mostly plankton, compared with older larvae, which consumed a diversity of macroinvertebrates in addition to plankton. Our results indicate that description of broad-headed larvae as cannibals is justified because most of their diet is other salamanders, while typical morphs rarely eat salamanders. Both morphs also eat invertebrates. With regard to diet in larval A. tigrinum, therefore, "cannibalistic" versus "typical" refers to a predilection and is not an absolute categorization.

A model of inter-cohort cannibalism and paedomorphosis in Arizona Tiger Salamanders, Ambystoma tigrinum nebulosum

2016 ◽  
Vol 09 (02) ◽  
pp. 1650030
Author(s):  
Maeve L. McCarthy ◽  
Howard H. Whiteman
Keyword(s):  
Periodic Solutions ◽  
Structured Populations ◽  
Unstable Equilibrium ◽  
Ambystoma Tigrinum ◽  
General Applicability ◽  
Previous Theory ◽  
Tiger Salamanders ◽  
Stable Equilibria ◽  
Per Capita ◽  
Ambystoma Tigrinum Nebulosum

Cannibalism is widespread in size-structured populations. If cannibals and victims are in different life stages, dominant cohorts of cannibals can regulate recruitment. Arizona Tiger Salamanders, Ambystoma tigrinum nebulosum, exhibit facultative paedomorphosis in which salamander larvae either metamorphose into terrestrial adults or become sexually mature while still in their larval form. Although many salamanders exhibit cannibalism of larvae, the Arizona Tiger Salamander also exhibits cannibalism of young by the aquatic adults. We formulate a differential equations model of this system under the assumption that the terrestrial adults do not impact the system beyond their contribution to the birth of young larvae. We establish non-negativity, boundedness and persistence of the salamander population under certain assumptions. We consider the equilibrium states of the system in the presence or absence of a birth contribution from the terrestrial or metamorph adults. Constant per capita paedomorphosis leads to asymptotically stable equilibria. The per capita paedomorphosis rate of the larvae must be density dependent in order for periodic solutions to exist. Furthermore, the stage transition rate must be sufficiently decreasing in order to guarantee the existence of an unstable equilibrium. Periodic solutions are only possible in the presence of a unique nontrivial unstable equilibrium. Our results conform to previous theory on paedomorphosis which suggests general applicability of our results to similar systems.

Seasonal movement patterns in a subalpine population of the tiger salamander, Ambystoma tigrinum nebulosum

1994 ◽  
Vol 72 (10) ◽  
pp. 1780-1787 ◽  
Author(s):  
Howard H. Whiteman ◽  
Scott A. Wissinger ◽  
Andrew J. Bohonak
Keyword(s):  
Breeding Season ◽  
Ambystoma Tigrinum ◽  
Tiger Salamander ◽  
High Quality ◽  
Terrestrial Environment ◽  
Seasonal Movements ◽  
Tiger Salamanders ◽  
Seasonal Movement ◽  
Ambystoma Tigrinum Nebulosum ◽  
Branchinecta Coloradensis

Seasonal movements of a subalpine population of metamorphic tiger salamanders, Ambystoma tigrinum nebulosum, were explored from 1990 to 1992. Metamorphic adults bred in permanent and semipermanent habitats during June of each year. After breeding, soma individuals returned to the terrestrial environment, but many remained and congregated in nonpermanent ponds. Metamorphic adults in nonpermanent ponds included those that moved from permanent ponds, those that bred and remained in semipermanent ponds, and those that did not breed but migrated from the terrestrial environment after the breeding season. Dietary analyses indicated that metamorphic adults in nonpermanent ponds have significantly greater numbers, biomass, and calories of prey in their gut than the few metamorphic adults remaining in permanent ponds. This difference was due to the presence of fairy shrimp (Branchinecta coloradensis), which composed 91 % of metamorphic adult diets in nonpermanent ponds and accounted for three times the average caloric value of all prey in gut samples from metamorphic adults in permanent ponds. Intraspecific competition also may have contributed to movement into nonpermanent ponds: post-breeding densities of metamorphic adults in permanent ponds were inversely related to the densities of other morphs (paedo-morphic adults and large larvae). We conclude that metamorphic A. t. nebulosum in this population utilize nonpermanent ponds after the breeding season because of the abundance of high-quality aquatic prey and reduced competition from con-specific morphs.

Microsatellite analyses across three diverse vertebrate transcriptomes (Acipenser fulvescens, Ambystoma tigrinum, and Dipodomys spectabilis)

Genome ◽  
2013 ◽  
Vol 56 (7) ◽  
pp. 407-414 ◽  
Author(s):  
Jacqueline M. Doyle ◽  
Gregor Siegmund ◽  
Joseph D. Ruhl ◽  
Soo Hyung Eo ◽  
Matthew C. Hale ◽  
...  
Keyword(s):  
Lake Sturgeon ◽  
Untranslated Regions ◽  
Ambystoma Tigrinum ◽  
Acipenser Fulvescens ◽  
Data Sets ◽  
Noncoding Dna ◽  
Kangaroo Rats ◽  
Tiger Salamanders ◽  
Dipodomys Spectabilis ◽  
In Silico Polymorphism

Historically, many population genetics studies have utilized microsatellite markers sampled at random from the genome and presumed to be selectively neutral. Recent studies, however, have shown that microsatellites can occur in transcribed regions, where they are more likely to be under selection. In this study, we mined microsatellites from transcriptomes generated by 454-pyrosequencing for three vertebrate species: lake sturgeon (Acipenser fulvescens), tiger salamander (Ambystoma tigrinum), and kangaroo rat (Dipodomys spectabilis). We evaluated (i) the occurrence of microsatellites across species; (ii) whether particular gene ontology terms were over-represented in genes that contained microsatellites; (iii) whether repeat motifs were located in untranslated regions or coding sequences of genes; and (iv) in silico polymorphism. Microsatellites were less common in tiger salamanders than in either lake sturgeon or kangaroo rats. Across libraries, trinucleotides were found more frequently than any other motif type, presumably because they do not cause frameshift mutations. By evaluating variation across reads assembled to a given contig, we were able to identify repeat motifs likely to be polymorphic. Our study represents one of the first comparative data sets on the distribution of vertebrate microsatellites within expressed genes. Our results reinforce the idea that microsatellites do not always occur in noncoding DNA, but commonly occur in expressed genes.

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