Jerry D. Johnson

Foods of the Pallid Bat, Antrozous pallidus (Chiroptera: Vespertilionidae), in the Chihuahuan Desert of Western Texas

Abstract Pallid bats, Antrozous pallidus, glean prey off the ground or from vegetation. During 27 March-19 November 2004, culled parts of prey were collected from under a night roost on Indio Mountains Research Station, Hudspeth County, Texas. Adjacent pitfall traps were monitored concurrently to determine species richness and seasonal abundance of potential prey. Prey representing 44 morphospecies from 4 classes, 13 orders, 25 families, and 34 genera were recovered and identified. Of the identified morphospecies, 29 were unrecorded previously in diet of the pallid bat. Orthopterans were the highest percentage of prey (44.1%), followed by coleopterans (26.8%), and solifugids (16.2%), but most taxa were represented by <4% of the total. Conclusions are that arthropods are the primary food source, but a wide variety of species are consumed, there is occasional predation on vertebrates (three species of lizards), there are statistical differences between amount of prey eaten and abundance of prey in the same geographic area indicating selective foraging behavior, there are seasonal dietary shifts associated with common prey items, and there is geographic variation in diet of pallid bats when compared to studies from other localities within its geographic range.

Reproductive Characteristics of Two Syntopic Whiptail Lizards, Aspidoscelis marmorata and Aspidoscelis tesselata, from the Northern Chihuahuan Desert

Abstract We studied reproductive characteristics of two syntopic whiptail lizards, Aspidoscelis marmorata and A. tesselata, inhabiting the northern Chihuahuan Desert. Reproductive characteristics studied were snout–vent length at sexual maturity, size of clutch, and volume of eggs. In A. marmorata, males and females were similar in snout–vent length, but body mass was larger in males than in females. Female A. tesselata were larger in snout-vent length and heavier than female A. marmorata. Mean size of clutch was 3.3 for A. marmorata and 3.5 for A. tesselata. Females of A. marmorata had larger volume of eggs than females of A. tesselata. Data suggest that both A. marmorata and A. tesselata respond to environmental factors of the region in different ways.

A TAXONOMIC REVISION OF TRIMORPHODON BISCUTATUS VILKINSONII (SERPENTES: COLUBRIDAE)

Formerly considered a full species, Trimorphodon biscutatus vilkinsonii is presently regarded as a subspecies of T. biscutatus based on morphological data compiled from eight male specimens from southeastern Arizona and southwestern New Mexico; these specimens were thought to be intermediate between the currently recognized T. b. lambda (from Sonora and Arizona) and T. b. vilkinsonii (from Chihuahua and Texas). We performed univariate and multivariate statistical analyses of a morphological data set compiled for T. b. vilkinsonii, T. b. lambda, and specimens collected from the intermediate zone. Our analyses indicate that T. b. vilkinsonii is clearly distinct from T. b. lambda. Several characters, such as blotch width and interblotch distance, allowed more than 95% of specimens of both taxa to be classified properly. Our data also confirm that specimens sampled from the intermediate zone should be considered T. b. lambda. We find the T. b. vilkinsonii populations represent a separate, distinct lineage, and we elevate this taxon to species level.

Rainwater-harvesting by the rock rattlesnake, Crotalus lepidus, in the Chihuahuan Desert of western Texas

Abstract Two instances of rainwater-harvesting behavior by the rock rattlesnake, Crotalus lepidus, are reported. The first observation was of a male collecting water from rain and sleet on 16 February 2008, and the second observation involved another male collecting rainwater on 11 July 2008. The observations took place within a Chihuahuan Desert landscape located in extreme southeastern Hudspeth County, Texas.

Comparison of Diets of Two Syntopic Lizards, Aspidoscelis marmorata and Aspidoscelis tesselata (Teiidae), from the Northern Chihuahuan Desert of Texas

Abstract We compared types and volume of prey in the diets of two whiptail lizards (Teiidae), Aspidoscelis marmorata (a bisexual species) and A. tesselata (a unisexual species) that occur syntopically in a Chihuahuan Desert landscape on Indio Mountains Research Station, Hudspeth County, Texas. Because their home ranges overlap extensively, we hypothesized that there would be dietary resource partitioning between the two species. Stomach contents of 69 A. marmorata and 21 A. tesselata included only arthropods. Aspidoscelis marmorata used 14 orders of arthropods for prey, while A. tesselata used eight orders. Isopterans (termites) were the principal food for both species by count (93.5 and 83.8% in male and female A. marmorata, respectively; 94.6% in A. tesselata). By volume, Homoptera (37.8 and 10.3%), Araneae (11.9 and 54.1%), Orthoptera (18.0 and 0.9%), and Isoptera (16.6 and 3.6%) composed 84.3 and 68.9% of the diet of male and female A. marmorata, respectively; whereas Orthoptera (29.8%), Homoptera (29.7%), Araneae (16.6%), and Isoptera (16.2%) were 92.3% of the diet of A. tesselata. The hypothesis that syntopic A. tesselata and A. marmorata were partitioning food resources on the study area was not supported; both species are opportunistic feeders that consume similar food types. Resumen Comparamos el tipo y volumen de presas en la dieta de dos lagartijas de la familia Teiidae, Aspidoscelis marmorata (bisexual) y A. tesselata (unisexual), que ocurren sintópicamente en la Estación de Investigación, Indio Mountains Research Station, en el condado de Hudspeth, Texas, localizada en el desierto chihuahuense. Se asumió una repartición de recursos en la dieta de las dos especias debido a que sus rangos de hogar se sobreponen ampliamente. Los contenidos estomacales de 69 A. marmorata y 21 de A. tesselata incluyeron solamente artrópodos. Las presas consumidas por A. marmorata pertenecieron a 14 órdenes, mientras que las presas de A. tesselata pertenecieron a 8 órdenes. Por conteo, ambas especies consumieron isópteros (termitas) principalmente (93.5% y 83.7% en machos y hembras de A. marmorata, respectivamente; 94.6% en A. tesselata). Por volumen, Homoptera (37.8% y 10.3%), Araneae (11.9% y 54.1%), Orthoptera (18.0% y 0.9%), e Isoptera (16.6% y 3.6%) formaron el 84.3% y 68.9% de la dieta de machos y hembras de A. marmorata, respectivamente; mientras que Orthoptera (29.8%), Homoptera (29.7%), Araneae (16.6%), e Isoptera (16.2%) formaron el 92.3% de la dieta de A. tesselata. Los resultados contradicen la hipótesis indicando que las dos especies sintópicas no se reparten los recursos alimentarios; ambas especies son oportunistas que consumen presas similares.

First Record of Anisota oslari from Trans-Pecos, Texas Using Sandpaper Oak as a Host

Few investigations exist on oakworm moths (Lepidoptera: Saturniidae: Anisota), which are medium to large-sized species often confused with butterflies (Holland 1915, Tuskes et al. 1996). Members of the genus Anisota have a small white spot on their forewings (Powell and Opler 2009). Other studies on various oakworm moths included an investigation of the gregarious behavior of Anisota senatoria Smith (Porter et al. 1997) and phylogenetic analyses of selected species (Burke and Peigler 2009). In addition, Oslar’s oakworm moth, Anisota oslari Rothschild, is described as having solid brown-colored females and males with a brownish-red dorsum with darker hindwings; but neither sex exhibits scattered black speckling on the body (Powell and Opler 2009). A. oslari normally inhabits oak (Quercus) scrub communities ranging on the west from southwestern Colorado through New Mexico and adjacent northern Mexico to southeastern Arizona, and to western Texas on the east; it seems to be rare in parts of its range, especially on the edges (Covell 2005). Known reproductive behaviors of the species include: generally mating in the morning, egg clusters deposited under oak leaves in the evening, and gregarious caterpillars overwinter in shallow underground chambers; metamorphosed adults fly from July through August. As far as we know, this is the first documented record of A. oslari from the Trans-Pecos, Texas region of the northern Chihuahuan Desert. Two species of oaks previously were recognized as host plants for A. oslari (Covell 2005): Mexican blue oak, Quercus oblongifolia Torrey, and scrub-live oak, Quercus turbinella Greene. Another species in our study areas is Sandpaper oak (Quercus pungens Liebman), a scrub oak in the Chihuahuan Desert and southcentral Texas. It is an evergreen reaching 6 meters in height with stiff leathery leaves with pubescent undersides (Powell 1998, Spellenberg et al. 2014) (Fig. 1). Sandpaper oaks characteristically occupy rocky slopes or open woodlands at elevations between 800 and 2,000 meters. Our study sites were at Indio Mountains Research Station, a University of Texas at El Paso-controlled natural reserve in the northern Chihuahuan Desert about 40 kilometers southwest of Van Horn in Hudspeth County, Texas (centered on 30.776667oN, 105.015833oW). Indio Mountains Research Station generally contains a variety of thorn-scrub vegetation habitats and associated fauna, including washes lined with Q. pungens (Worthington et al. 2018). To the best of our knowledge, this is the only documented case of A. oslari using Q. pungens as a host plant. Stages

Sceloporus smithi Hartweg and Oliver, 1937 (Squamata: Phrynosomatidae): distributional range extension and a new elevation record from Oaxaca, México

A male Sceloporus smithi was collected at Hierve El Agua, in the Municipality of San Lorenzo Albarradas, Oaxaca, Mexico. This record extends the known distribution of the species by approximately 25 km N from the closest acknowledged locality and also represents a new upward elevational record. Even though the elevation at this site is almost 700 m higher than for previously documented localities, the subhumid forest and igneous rock association is similar to other inhabited localities at lower elevations.