Cross reference: Dominance Hierarchies in General Salamander
Brain of the Tiger Salamander Salamander Brain Diagram
Salamander Brain Text Salamander Brain Illustrations
Aggression and Competition in Eastern Plethodon (Amphibia, Urodela, Plethodontidae)
Only abstract available online for free. I got PDF through the library.
from the abstract:
"Aggression (including territoriality, social dominance and feeding competition) was observed ..."
from the PDF:
"Interspecific and intraspecific aggression do occur in Plethodon, as reported for P. glutinosus, P. ouachitae, and P. caddoensis (Thurow, 1972a, b). This was the second report of salamander territoriality (after Grant, 1955) and, to my knowledge, the first report of individually identified combat peck order sequences, or social hierarchies, for salamanders"
"Greater weight (usually accompanied by greater size and strength, and larger teeth) not only confers a physical advantage to a salamander combatant, but a psychological one as well."
"I have repeatedly seen cases where one animal will drive another away from the home shelter of the first one, only to be in turn driven back when they got to the other animal's area"
The author gives several descriptions of complex intereactions among several individuals over an extended period of time that are clearly dominance hierarchies. He also suggests that females may also have a dominance hierarchy.
IIntraspecific Aggression and Responses to Marked Substrates in Ambystoma maculatum
Only the abstract is available online. I got PDF through the library.
"Many aspects of the ecology of terrestrial salamanders are influenced by intra- and interspecific competitive interactions. In particular, some species show interference competition in the form of territoriality and aggression. ... The most comprehensive work has been done on aggression, communication, territoriality, and ecology in Plethodon cinereus, which scent-marks substrates and defends territories using visual displays and biting."
"The A. maculatum males ... demonstrated aggression, avoidance of conspecifics, and possibly communication (by both visual displays and substrate marking). This study represents the first description of such behaviors in salamanders outside of the family Plethodontidae."
"Ninety-six percent of the salamanders used either forebody elevation with head level or forebody elevation with head raised. Although both winners and losers employed these postures early in bouts, forebody elevations commonly preceded bites and were never used by either a salamander that had recently been bitten or by a retreating animal."
1. The described behavior pretty clearly indicates a male dominance hierarchy.
2. This study showed that Ambystoma salamanders demonstrate a male dominance hierarchy similar to that already documented in Plethodontida salamanders (see above).
Differential effects of mate competition and mate choice on eastern tiger salamanders.
Full length PDF available online for free. It's possible to copy-and-paste only after the PDF is downloaded.
from the abstract:
"Male tiger salamanders, Ambystoma tigrinum tigrinum, are slightly larger in body size and have considerably higher and longer tails than females. ... Larger males had an advantage in most aspects of mate competition investigated. ... Males with longer tails also had no advantage in mate competition but were preferred as mates by females.
Larger males interrupted courting males more often than smaller males did. The form of male–male interference was conditional on body size and not on either tail dimension. If the intruder was larger than the courting male, it would shove the female away from the courting male and initiate courtship; if the intruder was smaller, it adopted a female mimicry tactic in which it positioned itself between the courting male and female and performed female behaviours to the courting male while simultaneously courting the female.
Our trials indicated that the two components of sexual selection may influence the evolution of different male morphological traits in tiger salamanders. Mate competition may favour increased male body length; mate choice may select for greater male tail length."
from the PDF:
"Sexual selection ... consists of two components: interactions between members of the same sex for mating opportunities (mate competition) and proclivities to mate with individuals of the opposite sex that have particular characteristics (mate choice)."
"Some traits, such as body size, appear to be affected primarily by mate competition in some species, but by both sexual selection components in others. Other traits, such as male visual ornaments or displays, appear to be favoured mainly by mate choice in some species, but by mate competition in others. More rarely, the two sexual selection components may favour different traits in the same species."
"... some studies have revealed intense mate competition ..."
"In some salamander species, larger-bodied males have a mating advantage due to apparent success in mate competition; in other species, males with greater tail heights have increased mating success due to either mate competition or mate choice.
In great crested newts, Triturus cristatus, tail height correlates with body condition and could influence female mating decisions by indicating the resource acquisition ability of potential mates."
"Males with longer bodies had higher rates of female encounters ... Shoving rate and rate of spermatophore deposition also increased with male body length,"
"The influence of mate competition and mate choice differed for the three sexually dimorphic traits we considered in A. tigrinum. Longer body length in males provided advantages in many aspects of mate competition, but was not influenced by mate choice. In contrast, longer tail length in males was influenced by mate choice, but provided no advantages in mate competition. Higher tails in males was unrelated to both mate competition and mate choice."
"... the types of mate competition that occur in tiger salamanders, sexual defence (shoving females away from potential competitors) and sexual interference (depositing spermatophores on top of those laid by competitors) need not involve males assessing other males because combat is never involved." "We never observed male combat in A. tigrinum."
"Larger male body size provided advantages in almost every aspect of mate competition. Larger males had more encounters with females, shoved females more often to initiate courtship, deposited spermatophores more often and interrupted other courting males more often."
Life history and population characteristics of the salamander Plethodon kentucki with a review of Plethodon life histories.
Territorial behavior of the plethodontid salamander Plethodon kentucki: influence of habitat structure and population density
"Territoriality in terrestrial plethodontids may result from competition for food or feeding areas, cover objects or underground retreats that provide cool and moist microhabitats, underground oviposition sites, access to mates, or perhaps all-purpose home ranges. However, not all plethodontids are territorial, and territorial behavior may have only evolved in environments where resources are limited and/or economically defendable"
"Adult male residents were significantly more aggressive toward male intruders during the breeding season than during the non-breeding season (Mann-Whitney rank sum test, T = 194.5, P = 0.009), and were significantly more aggressive toward male intruders than toward either female or juvenile intruders during the breeding season"
"The home ranges of adults were fixed and the home ranges of same-sex adult neighbors were mostly exclusive. Additionally, the regular dispersion of adult home ranges was consistent with territorial behavior"
DEAN A. CROSHAW. (2010) Quantifying sexual selection: a comparison of competing indices with mating system data from a terrestrially breeding salamander. Biological Journal of the Linnean Society 99:1, 73-83
Online publication date: 1-Jan-2010.
Jaeger, R G, Gillette, J R and Cooper, R C (2002) Sexual Coercion in a Territorial Salamander: Males Punish Socially Polyandrous Female Partners, Animal Behaviour, 63(5), pp 871-877
The Influence of Residency Status on Agonistic Behavior of Male and Female Ozark Zigzag Salamanders, Plethodon Angusticlavius,
"Once territories become established residents often have a high probability of successfully defending their territories against intruders. This advantage often can be explained by intrinsic qualities (e.g., size, body condition, experience) that make residents superior competitors. In addition, residency status can confer an advantage that is independent of fighting ability."
"Males and females were tested in same-sex contests in separate experiments. ... These data are consistent with the hypothesis that both males and females defend feeding territories and that residency offers an advantage that is independent of fighting ability in this species."
Age, Growth, and Long-Term Site Fidelity in the Terrestrial Plethodontid Salamander Plethodon kentucki (Goog)
"Both male and female P. kentucki can be territorial, and some male home ranges overlap a greater number of gravid female home ranges where the density of females is higher (Marvin, 1998). Males that occupy a home range with a greater density of females may gain more matings. Females in an area with better resources such as good oviposition sites and high prey density or quality could have greater reproductive success. ...defense of a favorable home area could enhance the foraging success and growth of their progeny. "