نتایج جستجو برای: lizards
تعداد نتایج: 4756 فیلتر نتایج به سال:
Foraging mode is a functional trait with cascading impacts on ecological communities. The foraging syndrome hypothesis posits a suite of concurrent traits that vary with foraging mode; however, comparative studies testing this hypothesis are typically interspecific. While foraging modes are often considered typological for a species when predicting foraging-related traits or mode-specific casca...
Maintaining biodiversity within fragmented landscapes has become a primary focus of ecology. Despite many theoretical and comparative studies on species persistence following fragmentation, experimental studies investigating the mechanisms behind population declines remain rare. In recent years, coastal horned lizards (Phrynosoma coronatum) have disappeared throughout much of their range in coa...
One of the many interesting questions in evolutionary studies of varanid lizards is the origin of the genus Varanus. The fossil record indicates the earliest emergence of this genus on Gondwana, although the remains of early varanid lizards have been discovered in Laurasia. The relationships among extant Varanus can generally be inferred using molecular phylogenetic techniques, although several...
Effects of repeated pollutant exposure on growth, locomotor performance, and behavior have rarely been evaluated in reptiles. We administered three doses of malathion (2.0, 20, or 100mg/kg body weight) to western fence lizards (Sceloporus occidentalis) over an 81day period. Eight and 23% mortality occurred at 20 and 100mg/kg (p=0.079) and 85% of lizards in the 100mg/kg group exhibited clinical ...
Castilla, A. M., Van Damme, R. & Bauwens, D.: Field body temperatures, mechanisms of thermoregulation and evolution of thermal characteristics in lacertid lizards. Nat. Croat., Vol. 8, No. 3., 253–274, 1999, Zagreb. We discuss three aspects of the thermal biology of lacertid lizards. First, we provide an overview of the available data on field body temperatures (Tb), the thermal sensitivity of ...
The lizard family Phrynosomatidae comprises three subclades: the closely related sand and horned lizards, and their relatives the Sceloporus group. This family exhibits great variation in ecology, behavior, and general body plan. Previous studies also show that this family exhibits great diversity in locomotor performance abilities; as measured on a high-speed treadmill, sand lizards are except...
An experimental approach was taken to evaluate the role of phenotypic plasticity in reptile coloration for three lizard species which exhibit dramatic variation in dorsal body darkness associated with different substrate environments. In southern New Mexico, blanched color morphs of Aspidoscelis inornata, Holbrookia maculata, and Sceloporus undulatus inhabit the gypsum dunes of White Sands, and...
Conspicuous colouration can evolve as a primary defence mechanism that advertises unprofitability and discourages predatory attacks. Geographic overlap is a primary determinant of whether individual predators encounter, and thus learn to avoid, such aposematic prey. We experimentally tested whether the conspicuous colouration displayed by Old World pachyrhynchid weevils (Pachyrhynchus tobafoliu...
To establish whether the capability of daily melatonin injections to entrain circadian rhythms varies with season, we examined in constant conditions the locomotor behavior of lizards Podarcis sicula collected and subjected to daily melatonin injections at different times of the year. Although in summer locomotor rhythms of both pineal-intact and pinealectomized lizards became entrained to the ...
The negative consequences of parasitic infection (virulence) were examined for two lizard malaria parasite-host associations: Plasmodium agamae and P. giganteum, parasites of the rainbow lizard, Agama agama, in Sierra Leone, West Africa; and P. mexicanum in the western fence lizard, Sceloporus occidentalis, in northern California. These malaria species vary greatly in their reproductive charact...
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