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Behavioral Ecology and Sociobiology

, Volume 27, Issue 3, pp 153–157 | Cite as

Locomotor impairment and defense in gravid lizards (Eumeces laticeps): behavioral shift in activity may offset costs of reproduction in an active forager

  • William E. CooperJr.
  • Laurie J. Vitt
  • Richard Hedges
  • Raymond B. Huey
Article

Summary

Female Eumeces laticeps experience a substantial decrease in running speed (ca. 25%) and an even greater loss of endurance (slightly over 50%) while gravid. Because some widely foraging lizards, including E. laticeps, rely primarily on running to escape predators, the decreases in speed and stamina may contribute to an increased risk of predation. However, observations suggest that gravid females become less active or conspicuous on the surface. Ambush foraging lizards rely relatively more on crypsis associated with immobility to avoid predation and thus can have greater average relative clutch mass (RCM) than active foragers. Behavioral compensation for locomotor impairment by becoming less active or conspicuous may allow some species the advantages inherent in both high relative clutch mass when gravid and the increased energetic profitability of active foraging when not gravid. As females gain weight during the breeding season, they may forage actively until the risk due to increasing locomotor impairment becomes too great and then change defensive strategy to greater reliance on crypsis. Without such a shift, widely foraging squamate reptiles may be less able than ambush foragers to exploit life-historical strategies demanding high current investment in reproduction.

Keywords

Breeding Season Substantial Decrease Great Loss Great Reliance Gravid Female 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • William E. CooperJr.
    • 1
  • Laurie J. Vitt
    • 2
  • Richard Hedges
    • 3
  • Raymond B. Huey
    • 3
  1. 1.Department of BiologyAuburn University at MontgomeryMontgomeryUSA
  2. 2.Department of BiologyUniversity of CaliforniaLos AngelesUSA
  3. 3.Department of Zoology NJ-15University of WashingtonSeattleUSA

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