Response to Intruders and the Dear Enemy Phenomenon in Female Tree Lizards, Urosaurus ornatus, in Relation to Age and Reproductive Condition

A reduction of territory owners’ aggression towards their neighbours in relation to the intrusion of strangers characterises the dear enemy phenomenon. Supposedly, the disparity in aggression levels of territory owners is due to a higher threat imposed by strangers compared to the threat imposed by neighbours. To evaluate the occurrence of the phenomenon in males of the small-sized lizard Eurolophosaurus nanuzae we performed a field manipulative study. We considered three models to run intrusions in males’ territories: neighbour, tailed stranger (unfamiliar) and tailless stranger intruders. Our results lend support to the presence of dear enemy for this species as residents acted more aggressively towards strangers than to neighbours. In addition, the information we provide supports the relative threat hypothesis as territory owners were more aggressive towards tailed stranger intruders than to tailless stranger intruders. In this sense, tail condition can represent a trait that signals the ‘resource holding power’ (RHP) of a lizard. Therefore, we show that beyond neighbourhood recognition, residents are able to evaluate the potential threat of stranger intruders in general, thereby extending the evolutionary gains of the dear enemy by saving energy even in the context they are expected to acts with higher costs.

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Intraspecific variation in tree lizard escape behaviour in relation to habitat and temperature

Behaviour ◽

10.1163/1568539x-00003586 ◽

2020 ◽

Vol 157 (2) ◽

pp. 185-204 ◽

Cited By ~ 1

Author(s):

Cynthia L. Morris ◽

Matthew S. Lattanzio

Keyword(s):

Antipredator Behaviour ◽

Similar Response ◽

Response Patterns ◽

Escape Behaviour ◽

Urosaurus Ornatus ◽

Escape Theory ◽

Habitat Gradients ◽

Disturbance Gradient ◽

Tree Lizards ◽

Tree Lizard

Abstract Optimal escape theory has proven useful for understanding the dynamics of antipredator behaviour in animals; however, approaches are often limited to single-population studies. We studied how the escape behaviour of tree lizards (Urosaurus ornatus) varied across a disturbance gradient. We also considered how sex, body temperature, and perch temperature affected their escape decisions. Both sexes exhibited similar response patterns; however, lizards in the most-disturbed habitat, as well as cooler (body or perch temperature) lizards, initiated escape earlier (but did not flee further) than other animals. Increased wariness as indicated by earlier escape suggests that frequently-disturbed, more-open localities may be stressful habitats for species like U. ornatus. In addition, because cooler temperatures limit locomotor performance capacity, escape decisions should also depend on a species’ thermal ecology. Overall, we stress the importance of multi-population approaches for capturing the variety of ways species adaptively respond to the threat of predation across habitat gradients.

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Absence of kin discrimination in the hatchlings of a lizard, Calotes versicolor (Agamidae)

Animal Biology ◽

10.1163/15707563-00002393 ◽

2013 ◽

Vol 63 (1) ◽

pp. 47-58

Author(s):

Veena H.F. Ammanna ◽

Srinivas K. Saidapur ◽

Bhagyashri A. Shanbhag

Keyword(s):

Kin Discrimination ◽

Visual Displays ◽

Dear Enemy ◽

Discrimination Ability ◽

Dear Enemy Phenomenon ◽

Calotes Versicolor

Laboratory born Calotes versicolor hatchlings were reared for 15 days in pure or mixed sibships or singly in isolation and then tested for their kin discrimination ability. As C. versicolor orients itself visually, visual displays like push-ups, gular extensions, and distance between the test individuals were used as indicators of arousal/aggression towards the opponents (familiar vs. familiar/unfamiliar sib or non-sib). The hatchlings exhibited aggressiveness towards unfamiliar sibs as well as non-sibs in the form of push-ups and gular extensions; they also remained at a longer distance from each other. In contrast, they did not exhibit such behaviors against familiar individuals regardless of their relatedness, and stayed closer to each other. In tests involving once familiar individuals, sib, or non-sib reared together for 15 d from hatching and then separated for 7 or 30 d, the lizards showed aggressiveness towards each other following 30 d separation. A greater number of push-ups and gular extensions were exhibited by the test individuals after 30 d separation compared to those separated for 7 d. Thus, in this non-social lizard, there is no kin discrimination. An early dispersal of hatchlings in this species may have led to a loss of kin discrimination. However, familiar individuals are recognized as long as they continue to remain familiar thereby suggesting a ‘dear enemy phenomenon’.

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