Opportunistic feeding in Sceloporus horridus from Jalisco, Mexico

Medica, Philip A.; Arndt, Rudolf G.

doi:10.5962/bhl.part.17199

Cited by 4 publications

(3 citation statements)

References 10 publications

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“…Data on the occupation of mainland vs island habitats, aridity, and cave dwelling were obtained from the dietary papers or sources of SVL data. SVLs were taken from Bogert & Ma Ârtin del Campo (1956), Schall (1974), Carey (1975), Fitch (1975, Medica & Arndt (1976), Andrews (1979), Crisp, Cook & Hereward (1979), Vanzolini, Ramos-Costa & Vitt (1980), Barbault & Maury (1981), Fitch & Seigel (1984), Stebbins (1985), Pianka (1986), Conant & Collins (1991), Cusumano & Powell (1991), Schwartz & Henderson (1991), Jenssen & Feely (1991), Vitt (1991Vitt ( , 1995Vitt ( , 2000, Cogger (1992), Cei (1993), Cree (1994), Avila-Pires (1995), Losos (1995), Vitt & De Carvalho (1995), Rocha (1996), Vitt & Zani (1996a,b,c), Gadsden & Palacios-Orona (1997), Branch (1998), Campbell (1998), Van Sluys (1998), Barbadillo et al (1999), Colli & Zamboni (1999), Durtsche (1999), Van Damme (1999), G. Smith, Ballinger & Lemos-Espinal (2000), and papers cited for dietary data.…”

Section: Methodsmentioning

confidence: 99%

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Distribution, extent, and evolution of plant consumption by lizards

2002

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Animal diets crucially affect ®tness, yet many aspects of their ultimate determinants are unknown. The distribution and extent of herbivory in lizards, its evolutionary history, and ecological factors that may favour it are discussed. Most lizards are exclusively or primarily carnivorous, yet many species eat some plants and a few are almost exclusively herbivorous. Based on a literature survey of diets of over 450 lizard species, the distribution and degree of omnivory and herbivory are described. Some plants occur in the diets of slightly over half of lizard species, and plants formed 10% or more of the dietary volume of 12.1% of species, and 90% or more of the diet of 0.8% of species. The greatest percentage of omnivorous species (> 10% plant diet), over 30% in each, and highest mean percentage plant matter in the diet are in Iguanidae, Corytophanidae, Gerrhosauridae, Agamidae, Xantusiidae, and Tropiduridae. Numerous other omnivores occur in Lacertidae and Scincidae and fewer in several additional families. Herbivorous lizards (> 90% plant volume) tend to be folivorous and to possess adaptations for processing leaves, including specialized dentition for cutting or reducing leaves, elongated intestines, colic valves that slow passage of food, and intestinal¯ora that digest cellulose. Omnivorous lizards lacking such specializations may eat some leaves, but consume much more fruit,¯owers, and seeds, plant parts that are easy to digest, likely to be very abundant seasonally, and may be highly nutritious. Some lizards eat nectar and pollen; even sap is eaten by at least one gecko. Ontogenetic increase in plant consumption and decrease in prey consumption is known, but its generality has been controversial. Such ontogeny has been demonstrated in three iguanid species, a skink, a lacertid, two tropidurids, a phrynosomatid, and two corytophanids, but it does not occur in some other species. Thus, the presences of ontogenetic variation must be evaluated for each species. The importance of speci®c foods may also vary with age. Omnivory and/or herbivory have originated in many lizard families, with at least nine origins in Iguania and 23 in Scleroglossa. Origins have been rare in Gekkonoidea and Anguimorpha and common in Scincomorpha, especially in Lacertidae and Scincidae. Losses of omnivory have been much less frequent than gains. Only a few origins can account for all the herbivory in lizards. Concentrated changes tests show that there is a signi®cant association in Lacertidae, Lacertiformes, Lacertoidea, Scincidae, and Scleroglossa between insularity and omnivory. Insular lizards may broaden their diets to compensate for limited availability of prey. Addition of other factors that reduce availability of prey, i.e. extreme aridity and cave-dwelling, to insularity, strengthened the relationship to omnivory in Lacertidae and Lacertoidea. We were unable to demonstrate a role of aridity independent of insularity, but present anecdotal evidence suggests that it may promote evolution of plant consumption. Large body size in...

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Section: Methodsmentioning

confidence: 99%

“…Carnivorous lizards sometimes ingest leaves, blades of grass, or fragments of them in very small quantities, but such ingestion seems to be accidental or incidental to ingestion of prey, as is ingestion of sand, dirt, wood, and other objects in small amounts (e.g. Dixon & Medica, 1966;Medica & Arndt, 1976;Van Wyk, 2000).…”

Section: Parts Of Plants Eatenmentioning

confidence: 99%

Distribution, extent, and evolution of plant consumption by lizards

2002

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“…Most species of Sceloporus are insectivorous (e.g., Dixon and Medica, 1966;Tanner and Wright, 1973;Whitaker and Maser, 1981;Goldberg and Bursey, 1996). However, substantial plant intake has been observed in three species, S. poinsettii among them, in arid northern Mexico in time of extreme prey scarcity (Medica and Arndt, 1976;Barbault et al, 1985). Plants have been observed to exceed 10% of the volume of stomach contents only twice in any species of Sceloporus from a single location (Barbault et al, 1985).…”

Section: Introductionmentioning

confidence: 99%

Responses to prey and plant chemicals by three iguanian lizards: relationship to plants in the diet

Espinoza¹,

Habegger²,

Cooper³

2001

Amphib Reptilia

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We examined responses of three iguanian lizards, the phrynosomatid Sceloporus poinsettii and the tropidurids Tropidurus hispidus and Phymaturus punae, to prey chemicals and plant chemicals. When chemical stimuli were presented on cotton swabs or on ceramic tiles, neither S. poinsettii nor T. hispidus discriminated among prey, plant, and control stimuli. In contrast, an individual of P. punae discriminated both prey and plant chemicals from control stimuli in swab tests, typically biting swabs bearing prey or plant cues. These findings are consistent with the hypothesis that plant chemical discrimination evolves in herbivorous iguanians such as P. punae. Sceloporus poinsettii, which appears to be entirely insectivorous at some times, but eats substantial quantities of flowers at others, did not discriminate among the stimuli. Because all previously tested herbivores and omnivores responded strongly to prey and plant chemicals, the absence of such discriminations by S. poinsettii raises questions about the degree and regularity of herbivory that may be required for plant chemical discrimination to evolve. The results extend the absence of prey chemical discrimination in ambush foragers to T. hispidus.

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