Printer Friendly

Diet of the Tepalcatepec Valley whiptail, Aspidoscelis calidipes (Squamata: Teiidae), in Michoacan, Mexico.

Information about diet composition is essential in order for us to understand aspects of the ecology and natural history of species and populations (Sutton et al., 2006). For instance, diet information is important for us to understand the food partition resources and competition among species (Pianka, 1986) as well as to assess morphological and physiological changes that can lead to dietary change among organisms (Piersma and Drent, 2003). Therefore, diet information is an important issue in modern biology and conservation of species (Sih and Christensen, 2001).

The teiid lizard Aspidoscelis calidipes is endemic to the Balsas-Tepalcatepec Basin in the states of Michoacan and Guerrero, Mexico (Duellman, 1961; Perez-Ramos et al., 2000). Although, the International Union for Conservation of Nature (2011) places A. calidipes in the category of "Least Concern," Mexican conservation laws (Diario Oficial de la Federacion, 2010) categorize it as requiring special protection due to its degree of endemism and the loss and degradation of its habitat, Alvarado-Diaz et al. (2013) consider A. calidipes to have a high vulnerability. Data available on A. calidipes are restricted to a species description (Duellman, 1955) and limited field observations on type of habitat (arid tropical dry forest, particularly the Cercidium-Prosopis-Apaplonesia associations) and activity (active throughout the day, including the hottest times of the day when ground temperatures frequently reach [greater than or equal to] 40[degrees]C) (Duellman, 1960). We assessed the food habits of this species, specifically the differences in diet composition between adults and juveniles.

Our study was conducted at Nuevo Centro in the municipality of La Huacana (18[degrees]44'N, 102[degrees]00'W) in the Balsas-Tepalcatepec Basin of Michoacan, Mexico. Vegetation type in the area is dry tropical forest (CONANP, 2006). Mean annual temperature is 28[degrees]C with an average annual rainfall of 500 mm, 80% of which falls June-September, after 7-8 months of dry season (Garcia, 1988; Villaseuor et al., 2008).

We caught 22 lizards in March 2010 and February 2011. For each individual we measured (using a vernier caliper, to the nearest 0.1 mm) the snout-vent length (SVL). Lizards were assigned to two size-age classes (adults, SVL > 69 mm; juveniles, SVL < 69 mm). We assigned individuals to either category following Duellman's (1960) description of A. calidipes (juveniles present a dark dorsum and bluish tail; adults present a cocoa brown dorsum with reddish tail). We extracted stomach contents by stomach flushing (Rivas et al., 1996) and preserved food items in 70% ethanol. After we obtained the stomach contents, we released the lizards at the capture site. We identified prey items to taxonomic level of order or family. We counted prey and measured prey items volumetrically. We calculated the relative abundance by number (% N), relative abundance by volume (% V), and relative number of stomachs that contained the respective food item as frequency of occurrence (% F). Using these values, we calculated the index of relative importance (IRI): IRI = (% N + % V) x (% F) (Pinkas et al., 1971). This index ranges from 0.0-20,000, with higher values representing food types of greater importance. We estimated dietary diversity and overlap using the index of relative importance. We calculated the Shannon-Wiener index (H') to estimate diet diversity (Krebs, 1999). The diversity index increases with an increment in the number of dietary items; therefore low values represent dietary specialists and high values represent dietary generalists. As a descriptive measure for the similarity of diet between adult and juvenile lizards, we used the index of Morisita-Horn (Wolda, 1981).

The mean SVL of adult lizards (n = 12) collected was 74 [+ or -] 5.0 mm (range: 72-77 mm) and mean weight was 11.75 [+ or -] 0.38 g (range: 9.2-13.8 g). The mean SVL of juveniles (n = 10) was 63 [+ or -] 1.5 mm (range: 53-69 mm) and mean weight was 6.48 [+ or -] 0.55 g (range: 4.0-9.8 g). Of the 22 lizards examined only two presented empty stomachs. Aspidoscelis calidipes consumed 27 different prey types. Termites (Termitidae: Gnathamitermes) were the dominant prey item, presenting the highest values of IRI, number, volume, and frequency of occurrence in the overall sample and in adults and juveniles (Table 1). The next most important dietary items were Hymenoptera, Formicidae, and Coleoptera (Table 1). Overall dietary diversity was H' = 0.45. Afidae, Carabidae, Psyllidae, and Tingidae were absent in the diet of adults and Apidae, Coreidae, and Myrmeleontidae were absent in the diet of juveniles. The diversity index was higher in juveniles (H0 = 1.15) than in adults (H' = 0.28). Dietary overlap between adults and juveniles was 49%.

The low dietary diversity (H' = 0.45) found in A. calidipes resulted from the markedly high contribution of one prey item (termites) to diet composition. Dominance of termites in diet composition is a common phenomenon in species of the Teiidae (e.g., Mitchell, 1979; Baltazar and Hernandez, 1985). Although we registered differences in diet composition in some secondary food items between adults and juveniles of A. calidipes, as has been reported for other Aspidoscelis species (e.g., Vitt and Ohmart, 1977; Gannon et al., 1990), termites were the dominant item in both size classes. Dietary studies of Aspidoscelis deppii varies in different populations, from Coleoptera and Hymenoptera (Altamirano and Soriano, 2006) to termites, as the primary items (Vitt et al., 1993), suggesting that diet of different populations could be due to differences in prey availability rather than differences in feeding preferences (Altamirano and Soriano 2006). As an active forager (Huey and Pianka, 1981; Pianka, 1986) A. calidipes forages mainly in patches that support large numbers of relatively sedentary prey such as termites, a prey type that feeds lizards that are active foragers worldwide (Pianka and Vitt, 2003). The termites found in the stomach samples of A. calidipes correspond to the genus Gnathamitermes, i.e., "desert termites," which are restricted to desert and arid lands (Baker and Marchosky, 2005). These termites construct extensive networks of tunnels and chambers underground (Light and Pickens, 1934).

We conclude that A. calidipes presents the general pattern of wide-foraging behavior typical of the family Teiidae (Pianka and Vitt 2003) with a diet composed mainly of relatively sedentary prey. The rank of termites as the main prey item in both adults and juveniles might be the result of isopterans being small-sized prey, with reduced variation in size. Additionally, the aseasonal occurrence of termites, as well as their clumped distribution, makes them advantageous prey for A. calidipes, independent of lizard size.

We thank L. Reyes-Solorio and his family for their logistical support in field activities. We thank A. L. Escalante-Jimenez for identifying food items. We thank O. Medina-Aguilar, J.T. Perez, J. Orozco, and J. Paz-Gutierrez for their collaboration in the field. Field work was conducted under Secretaria de Medio Ambiente y Recursos Naturales (SEMARNAT) permit FAUT-0113. We thank to the Coordinacion de Investigacion Cientifica de la Universidad Michoacana de San Nicolas de Hidalgo. The results of the present study are part of the professional thesis of the principal author, under the direction of Dr. Ireri Suazo-Ortuho.

LITERATURE CITED

ALTAMIRANO, A. T., AND M. SORIANO. 2006. Espectro alimentario de Aspidoscelis deppii (Reptilia: Teiidae). Revista de Zoologia 17:37-45.

ALVARADO-DIAZ, J., I. SUAZO-ORTUNO, L. D. WILSON, AND O. MEDINAAGUILAR. 2013. Patterns of physiographic distribution and conservation status of the herpetofauna of Michoacan, Mexico. Amphibian and Reptile Conservation 7:128-170 (e71).

BAKER, P. B., AND R. J. MARCHOSKY. 2005. Arizona termites of economic importance. Cooperative Extension College of Agriculture and Life Sciences, University of Arizona, Tucson.

BALTAZAR, T. E., AND G. E. HERNANDEZ. 1985. Analisis de las dietas de doce lagartijas simpatricas del desierto sonorense. Tesis de licenciatura. Instituto de Ecologia. Universidad Autonoma Metropolitana Unidad Iztapalapa. Mexico, D.F.

[CONANP] COMISION NACIONAL DE AREAS NATURALES PROTEGIDAS. 2006. Estudio Previo Justificativo para el establecimiento de la Reserva de la Biosfera Zicuiran Infiernillo. Mexico, D.F.

DIARIO OFICIAL DE LA FEDERACION. 2010. NORMA Oficial Mexicana NOM-059-SEMARNAT-2010, Proteccion ambiental-Especies nativas de Mexico de flora y fauna silvestres-Categorias de riesgo y especificaciones para su inclusion, exclusion o cambio-Lista de especies en riesgo. Mexico, D.F.

DUELLMAN, E. W. 1955. A new whiptail lizard, genus Cnemidophorus, from Mexico. Occasional Papers of the Museum of Zoology University of Michigan 574:1-7.

DUELLMAN, E. W. 1960. Variation, distribution and ecology of Mexican teiid lizard Cnemidoporus calidipes. Copeia 2:97-101.

DUELLMAN, E. W. 1961. The amphibians and reptiles of Michoacan, Mexico. University of Kansas Publications, Museum of Natural History, Lawrence Kansas.

GANNON, M. R., M. R. WILLING, H. B. WILLIS, AND M. P. MOULTON. 1990. Intraspecific comparisons of diet of Cnemidophorus gularis (Sauria: Teiidae) in central Texas. Texas Journal of Science 42:264-272.

GARCIA, E. 1988. Modificaciones al sistema de clasificacion climatica de Koppen. Instituto de Geografia, Universidad Nacional Autonoma de Mexico, Mexico, D.F.

HUEY, R. B., AND E. R. PIANKA. 1981. Ecological consequences of foraging mode. Ecology 62:991-999.

INTERNATIONAL UNION FOR CONSERVATION OF NATURE. 2011. Guidelines for using the IUCN Red List categories and criteria. Available at: www.iucnredlist.org. Accessed 18 October 2013.

KREBS, C. J. 1999. Ecological methodology. Second edition. Benjamin-Cummings, Menlo Park, California.

LIGHT, S. F., AND A. L. PICKENS. 1934. American subterranean termites, their classification and distribution. Pages 150-156 in Termites and termite control (C. A. Kofoid, editor). University of California Press, Berkeley.

MITCHELL, J. C. 1979. Ecology of southeastern Arizona whiptail lizards (Cnemidophorus: Teiidae). Population densities, resource partitioning, and niche overlap. Canadian Journal of Zoology 57:1487-1499.

PEREZ-RAMOS, E., L. SALDANA DE LA RIVA, AND Z. URIBE-PENA. 2000. A checklist of the reptiles and amphibians of Guerrero, Mexico. Anales del Instituto de Biologia 71:21-40.

PIANKA, E. R. 1986. Ecology and natural history of desert lizards: analyses of the ecological niche and community structure. Princeton University Press, Princeton, New Jersey.

PIANKA, E. R., AND L. J. VITT. 2003. Lizards: windows to the evolution of diversity. University of California Press, Berkeley, Los Angeles, London.

PIERSMA, T., AND J. DRENT. 2003. Phenotypic flexibility and the evolution of organismal design. Trends in Ecology and Evolution 18:228-233.

PINKAS, L., M. S. OLIPHANT, AND Z. L. IVERSON. 1971. Food habits of albacore bluefin, tuna and bonito in California waters. California Department of Fish and Game, Fish Bulletin 152:1-350.

RIVAS, J. A., C. R. MOLINA, AND T. M. AVILA. 1996. A non-flushing stomach wash technique for large lizards. Herpetological Review 27:72-73.

SIH, A., AND B. CHRISTENSEN. 2001. Optimal diet theory: when does it work, and when and why does it fail? Animal Behavior 61:379-390.

SUTTON, W. K., K. E. RASTALL, AND T. K. PAULEY. 2006. Diet analysis and feeding strategies of Rana pipiens in a West Virginia wetland. Herpetological Review 37:152-153.

VILLASENOR, G. L., J. D. ALVARADO, AND I. O. SUAZO. 2008. Estudio para la estimacion de riqueza, diversidad y abundancia de especies de anfibios, reptiles y aves para la identificacion de proyectos productivos potenciales en el ejido de Bellas Fuentes o La Estancia y sus anexos, municipio de La Huacana, Michoacan. Comision Nacional de Areas Naturales Protegidas CONANP. Morelia, Michoacan, Mexico.

VITT, J. L., AND R. D. OHMART. 1977. Ecology and reproduction of lower Colorado River lizards: II. Cnemidophorus tigris (Teiidae), with comparisons. Herpetologica 33:223-234.

VITT, J. L., P. A. ZANI, J. P. CALDWELL, AND R. D. DURTSCHE. 1993. Ecology of the whiptail lizard Cnemidophorus deppii on a tropical beach. Canadian Journal of Zoology 71:2391-2400.

WOLDA, H. 1981. Similarity indices, sample size and diversity. Oecologia 50:296-302.

Submitted 21 October 2013.

Acceptance recommended by Associate Editor, Fausto Mendez de la Cruz, 18 January 2015.

ERNESTO RAYA-GARCIA, * IRERI SUAZO-ORTUNO, AND JAVIER ALVARADO-DIAZ

Instituto de Investigaciones sobre los Recursos Naturales, Universidad Michoacana de San Nicolas de Hidalgo.

Morelia, Michoacan 58000, Maxico

* Correspondent: tuataraya@hotmail.com
Table 1--Stomach contents of Aspidoscelis calidipes in
Michoacan, Mexico. The top line in each entry is
presented as follows: percent in numbers/percent in
volume ([mm.sup.3])/percent of frequency of occurrence.
The number in the second line of each entry corresponds
to the index of relative importance.

Food item             Adults        Juveniles     Pooled
                     (n = 12)      (n = 10)

Acridae              0.10/4        0.38/1         0.16/3
                    24.03          9.74          36.84
Afidae               0             0.77/0         0.16/0
                     0             3.85           0.80
Apidae               0.20/0        0              0.16/0
                    11.43          0              7.47
Araneae              0.10/0        0              0.08/0
                     0.51          0              0.40
Blattodea            0.10/0        0              0.08/0
                     2.86          0              1.87
Carabidae            0             0.38/0         0.08/0
                     0             5.83           1.87
Coleoptera           0.71/4        4.62/3         1.52/4
                    81.21         38.70         112.66
Coreidae             0.10/0        0              0.08/0
                     5.21          0              3.34
Curculionidae        0.40/1        1.15/3         0.56/2
                    27.24         46.69          69.08
Diptera              0             0.77/0         0.16/0
                     0            15.50           4.54
Formicidae           2.53/2        3.08/1         2.64/2
                   127.90         69.59         193.79
Homoptera            0.10/0        6.15/2         1.36/1
                     0.51        133.32          47.78
Hymenoptera          0.51/4       11.92/31        2.88/14
                    26.06        431.73         263.50
Isoptera             0             2.31/0         0.48/0
                     0            15.44           3.87
Lepidoptera          0.10/0        0.77/4         0.24/2
                     5.21         27.28          25.90
Mantodea             0             0.38/7         0.08/2
                     0            40.99          15.08
Myrmeleontidae       0.20/1        0              0.16/0
                     8.07          0              5.21
Neuroptera           0             0.38/0         0.08/0
                     0             5.83           1.87
Opiliones            0.10/0        0              0.08/0
                     1.68          0              1.13
Orthoptera           0.10/0        1.15/3         0.32/2
                     5.21         75.90          47.52
Oxyopidae            0.10/0        0.38/0         0.16/0
                     2.86          5.83           7.47
Psyllidae            0             1.15/0         0.24/0
                     0             7.72           1.94
Salticidae           0.20/0        1.54/3         0.48/2
                    11.43         54.45          50.72
Solipugida           0.40/1        0.38/0         0.40/1
                    23.71          5.83          28.56
Termitidae          93.93/73      60.38/29       86.95/56
                 7,530.53      2,690.44      10,783.33
Thysanura            0             0.38/0         0.08/0
                     0             5.83           1.87
Tingidae             0             0.38/0         0.08/0
                     0             1.92           0.40
COPYRIGHT 2015 Southwestern Association of Naturalists
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2015 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:Notes
Author:Raya-Garcia, Ernesto; Suazo-Ortuno, Ireri; Alvarado-Diaz, Javier
Publication:Southwestern Naturalist
Article Type:Report
Geographic Code:1MEX
Date:Mar 1, 2015
Words:2388
Previous Article:Distribution and ecology of squirrels (Rodentia: Sciuridae) in Paraguay, with first country records for Sciurus Ignitus.
Next Article:Swimming black-crowned night-herons (Nycticorax nycticorax) kleptoparasitize american coots (Fulica Americana).
Topics:

Terms of use | Privacy policy | Copyright © 2021 Farlex, Inc. | Feedback | For webmasters |