Species In Texas Research Articles

Recent Collection of a False Spike (Quadrula mitchelli) in the San Saba River, Texas, with Comments on Habitat Use

Similar to other rare and endemic freshwater mussel species in Texas, the distribution and life history of the False Spike, Quadrula mitchelli, is poorly understood. Few recent locality records suggest that Q. mitchelli has been extirpated from much of its range and is declining in numbers at an alarming rate, which has led to it being petitioned for listing under the Endangered Species Act. We present our findings of the discovery of one live individual collected on the San Saba River, TX and provide information regarding the species’ habitat use. The discovery represents the second known population in Texas and the only record of a live individual from the San Saba River. Knowledge of habitat use may help identify populations in other streams and allow managers to develop recovery plans for Q. mitchelli. However, given the rarity of this species, Q. mitchelli potentially faces extinction unless prompt conservation action is taken by state and federal agencies.

Distribution of the Swift Fox (Vulpes velox) in Texas

Swift foxes (Vulpes velox) once occupied ca. 79 counties in Texas, but surveys in 1997–1998 indicated the range of the species was reduced to two counties. We used scat-transects and live-trapping during 2005–2007 to assess current distribution of the species in Texas. Our results indicated that distribution of the swift fox in Texas remains significantly reduced from the historical distribution and that population densities are low where the species currently exists.El zorro del desierto (Vulpes velox) antes ocupaba ca. 79 condados de Texas, pero muestreos en 1997–1998 indicaron que la distribución de la especie se redujo a dos condados. Se utilizaron excrementos a través de transectos y captura de animales vivos durante 2005–2007 para evaluar la distribución actual de la especie en Texas. Nuestros resultados indicaron que la distribución de el zorro del desierto en Texas sigue siendo significativamente reducida de la distribución histórica, y que las densidades poblacionales son bajas donde la especie existe en la actualidad.

False Spike,Quadrula mitchelli(Bivalvia: Unionidae), is Not Extinct: First Account of a Live Population in Over 30 Years

Abstract. During a recent survey a small population of Quadrula mitchelli (Simpson, 1895), a species thought to have been extinct, was discovered in Texas. In total, 7 live individuals were collected from the Guadalupe River near Gonzales, Gonzales County, Texas. Our finding represents the only known population for this species in Texas and the first record of live specimens in over 30 y, which is significant because this species is currently under review for protection under the Endangered Species Act.

An Economic Comparison of Prescribed Extreme Fire and Alternative Methods for Managing Invasive Brush Species in Texas: a Modeling Approach

This article presents the results of a study to determine the economic feasibility of using prescribed fire as a rangeland restoration practice on private land when ambient air temperature is greater than and humidity less than the standards endorsed by the United States Department of Agriculture (USDA) Natural Resource Conservation Service (NRCS). The objective of this study was to evaluate the economic effectiveness of using prescribed summer burns compared to more commonly used practices for managing invasive woody plants. The research incorporates four contiguous counties in the Rolling Plains, Edwards Plateau and South Texas Plains eco-regions in Texas. Focus group meetings were held with landowners and NRCS and Texas AgriLife Extension personnel to obtain information about the most common economic uses of rangeland resources by landowners, the dominant invasive brush species, and the most commonly used practices and associated costs for controlling these invasive plants. An investment feasibility model was used to compare the economic efficacy of applying extreme fire and other commonly applied treatments to manage invasive brush species in the three Texas eco-regions. The economic analysis indicated that extreme fire was economically superior in all three regions and was the only treatment alternative that resulted in positive returns on investments in the treatments. The analysis included cost-share, which indicated increased returns for extreme fire and less negative returns for alternative treatments. The results of our study have implications for the review of current NRCS technical standards with respect to prescribed fire.

Distribution, genetic analysis and conservation priorities for rare Texas freshwater molluscs in the genera Fusconaia and Pleurobema (Bivalvia: Unionidae)

BackgroundFreshwater bivalves in the order Unionoida are considered to be one of the most endangered groups of animals in North America. In Texas, where over 60% of unionids are rare or very rare, 15 species have been recently added to the state’s list of threatened species, and 11 are under consideration for federal listing. Due to insufficient survey efforts in the past decades, however, primary data on current distribution and habitat requirement for most of these rare species are lacking, thus challenging their protection and management. Taxonomic identification of endemic species based on shell morphology is challenging and complicates conservation efforts. In this paper we present historic and current distributional data for three rare Texas species, Fusconaia askewi, F. lananensis, and Pleurobema riddellii, collected during our 2003–2011 state-wide surveys and suggest appropriate conservation measures. In addition, we tested the genetic affinities of Fusconaia and similar species collected from eastern Texas and western Louisiana using cox1 and nad1 sequences.ResultsWe found that F. askewi still inhabits four river basins in eastern and northeastern Texas and can be locally abundant, while P. riddellii was found only in one river basin. Pleurobema riddellii was well-separated from F. askewi and grouped with the P. sintoxia clade. The sequences for F. lananensis were very similar to those for F. askewi, with a maximum difference of just over 1% for nad1 and only 0.7% for cox1, similar to the variation between F. askewi alleles. Except for one low difference (1.55%) with the partial cox1 sequence for F. burkei, all other Fusconaia populations, including those from the Calcasieu drainage, differed by over 2.3% for both genes.ConclusionsOur study suggested that F. lananensis is not a valid species, and it is likely that only one Fusconaia species (F. askewi or its probable senior synonym F. chunii) is currently present in East Texas, thus simplifying conservation efforts. Distribution range of both these regional endemics (F. askewi and P. riddellii) has been reduced in the last 80 years.

<p><strong>Mine-damaged leaves by </strong><strong><em>Phyllocnistis citrella</em></strong><em> </em><strong>Stainton provide refuge for phytoseiids on grapefruit in Florida and Texas*</strong></p>

Damages caused by pests to leaves can indirectly affect populations of other associated arthropods. The relative abundance of mites was compared across young healthy leaves, mature healthy leaves and mature leaves damaged by the citrus leafminer, Phyllocnistis citrella Stainton, on grapefruit in Florida and Texas. The spider mite Eotetranychus sexmaculatus (Riley) (Tetranychidae) was significantly more abundant on mined leaves in Florida, whereas in Texas tetranychids were found sporadically. Predaceous phytoseiid mites (Phytoseiidae) were significantly more abundant on mature mined leaves than on mature leaves without mines. Iphiseiodes quadripilis (Banks) (n= 139), Typhlodromalus peregrinus (Muma) (n= 122) and Euseius mesembrinus (Dean) (n= 18) were the most abundant phytoseiids in Florida; E. mesembrinus was the dominant species in Texas [>90% of identified specimens (n=13)]. Although relatively high numbers of predaceous stigmaeid mites (Stigmaeidae) were found in some occasions in Florida, they had a patchy distribution, resulting in no significant differences between mined and unmined leaf types in most sampling dates. They were not found in Texas.

Helminth Community Composition, Structure, and Pattern in Six Dove Species (Columbiformes: Columbidae) of South Texas

The helminth community composition and structure of 6 species of columbids residing in south Texas are reported and compared herein. Sixty individuals of the following species, rock pigeons (Columba livia [RP]), mourning doves (Zenaida macroura [MD]), Eurasian collared-doves (Streptopelia decaocto [ECD]), white-winged doves (Zenaida asiatica [WWD]), and common ground doves (Columbina passerina [CGD]), and 48 Inca doves (Columbina inca [ID]) were collected during the summer of 2006 and examined for helminths. Twelve helminth species were found (9 nematodes and 3 cestodes), representing 486 individuals. Nematodes numerically dominated the component community in all host species. Overall, helminth prevalence was similar among host sex within all dove species. However, prevalence of Skrjabinia bonini and Hymenolepis sp. in RPs was significantly different among host age groups (P = 0.01, P = 0.0002, respectively). Likewise, prevalence of Killigrewia delafondi was higher (P = 0.0001) in adult WWDs. Based on percent similarity and Jaccard's coefficient of community indices, helminth component communities were dissimilar, and the number of shared helminth species varied among host species. Data from this study suggest that the environment surrounding preferred host habitat and foraging strategies of each host species is the driving force behind helminth component communities. This study emphasizes the importance of examining co-occurring hosts at both local and regional scales to elucidate helminth community structure and patterns.

Glyphosate-Resistant Common Waterhemp (Amaranthus rudis) Confirmed in Texas

Glyphosate-resistantAmaranthusspecies are a recognized risk to U.S. agriculture. With affected cropland exceeding 1.2 million ha, this epidemic is particularly pertinent to agricultural regions that utilize an intensive glyphosate-based management program to control weedy pests. Before 2006, Texas had no identified glyphosate-resistant populations. Two independent common waterhemp populations exhibiting poor control by glyphosate were identified in Wharton County and Fort Bend County, TX in 2006 and 2008, respectively. The objective of the present research was to characterize the level of glyphosate resistance (50% lethal dose [LD50] and 50% reduction in growth rate [GR50]) in each population. Resistance levels in four putatively glyphosate-resistant common waterhemp biotypes selected from these two populations were compared with confirmed glyphosate-resistant and -susceptible common waterhemp populations under greenhouse conditions. The LD50value for the susceptible population (736 g ae ha−1) was equivalent to the 0.9× labeled rate of glyphosate, whereas the putatively resistant lines exhibited a broad range of resistance with LD50values ranging from 3.5 to 59.7× the labeled rate of glyphosate. The GR50value for the most resistant line was 2.5-fold greater than the susceptible biotype (317 g ae ha−1of glyphosate). These results confirm the first documented case of a glyphosate-resistant weed species in Texas.

Fast food in ant communities: how competing species find resources

An understanding of foraging behavior is crucial to understanding higher level community dynamics; in particular, there is a lack of information about how different species discover food resources. We examined the effect of forager number and forager discovery capacity on food discovery in two disparate temperate ant communities, located in Texas and Arizona. We defined forager discovery capacity as the per capita rate of resource discovery, or how quickly individual ants arrived at resources. In general, resources were discovered more quickly when more foragers were present; this was true both within communities, where species identity was ignored, as well as within species. This pattern suggests that resource discovery is a matter of random processes, with ants essentially bumping into resources at a rate mediated by their abundance. In contrast, species that were better discoverers, as defined by the proportion of resources discovered first, did not have higher numbers of mean foragers. Instead, both mean forager number and mean forager discovery capacity determined discovery success. The Texas species used both forager number and capacity, whereas the Arizona species used only forager capacity. There was a negative correlation between a species' prevalence in the environment and the discovery capacity of its foragers, suggesting that a given species cannot exploit both high numbers and high discovery capacity as a strategy. These results highlight that while forager number is crucial to determining time to discovery at the community level and within species, individual forager characteristics influence the outcome of exploitative competition in ant communities.

Host Status of Grapefruit and Valencia Oranges for Anastrepha serpentina and Anastrepha ludens (Diptera: Tephritidae)

Anastrepha serpentina (Wiedemann) (Diptera: Tephritidae) is sporadically captured in the Rio Grande Valley of Texas. Although its preferred hosts are in the Sapotaceae family, several varieties of Citrus, including grapefruit and oranges are listed as alternate hosts. Although Mexican fruit fly, Anastrepha ludens (Loew), is known to be a major pest of Citrus, doubt exists as to the status of Citrus as a breeding host for A. serpentina. To evaluate the host status of commercial Citrus for A. serpentina we compared oviposition and development with that of A. ludens under laboratory conditions with 'Rio Red' grapefruit (Citrus paradisi MacFayden) and 'Valencia' oranges [Citrus sinensis (L.) Osbeck] in different stages of maturity. Both fly species oviposited in early season fruit in which the eggs and larvae died in the fruit albedo. Survival of either species to the adult stage occurred in later season grapefruit. In oranges, no A. serpentina larvae survived compared with 150 A. ludens surviving to adults. Survival on both Citrus species was much lower for A. serpentina, only approximately 5% of eggs eclosed into larvae in grapefruit compared with approximatley 50% for A. ludens. In oranges approximately 16% of A. serpentina eggs eclosed compared with approximately 76% for A. ludens. In grapefruit, only one fourth as many A. serpentina larvae survived to the adult stage compared with A. ludens. Additional experiments were performed in a greenhouse on small, caged trees of la coma (Sideroxylon celastrinum H.B.K.), a Texas species of Sapotaceae. The A. serpentina females readily oviposited into these berries and normal adults emerged. The present low incidence of the adults, coupled with the high mortality during development of the larvae, suggests that Texas citrus is unlikely to support a breeding population of A. serpentina.

Effects of Applying Nitrogen on Yield of Introduced Perennial Summer Grass Cultivars in Oklahoma

Effects of Applying Nitrogen on Yield of Introduced Perennial Summer Grass Cultivars in Oklahoma

Supplements Containing Escape Protein Improve Redberry Juniper Intake by Goats

Abstract Redberry juniper ( Juniperus pinchotii Sudw.) is a common invasive plant species in west-central Texas. Goats will consume redberry juniper, but intake is limited by monoterpenoids found in the plant. Previous research has shown that goats will increase juniper intake through 1) conditioning and 2) protein supplementation. This study compared intake of juniper when goats received different protein supplements either with or without protein sources that are high in amino acids that escape digestion in the rumen. Recently weaned Boer-cross goats ( n = 47) were randomly placed into five treatments. Treatments 1, 2, 3, and 4 received a protein supplement and juniper for 1 h daily for 14 d, along with a basal diet of alfalfa pellets (2% body weight). Treatment 5 received only a basal diet of alfalfa pellets and juniper. All supplements were formulated to be isonitrogenous (37% crude protein [CP]). Treatment 1 contained cottonseed meal (high CP escape value), treatment 2 contained cottonseed meal and distiller’s dried grain (higher CP escape value), treatment 3 contained soybean meal (low CP escape value), and treatment 4 contained soybean meal and distiller’s dried grain (moderate CP escape value). Refusals of juniper, supplements, and alfalfa were weighed daily to determine intake. Supplementation with 1) cottonseed meal, 2) soybean meal, or 3) soybean meal and distillers dried grain did not influence ( P > 0.05) juniper intake. Conversely, goats supplemented with cottonseed meal and distiller’s dried grain ate more ( P

Character displacement in the fighting colours of Hetaerina damselflies.

Aggression between species is a seldom-considered but potentially widespread mechanism of character displacement in secondary sexual characters. Based on previous research showing that similarity in wing coloration directly influences interspecific territorial aggression in Hetaerina damselflies, we predicted that wing coloration would show a pattern of character displacement (divergence in sympatry). A geographical survey of four Hetaerina damselfly species in Mexico and Texas showed evidence for character displacement in both species pairs that regularly occurs sympatrically. Hetaerina titia, a species that typically has large black wing spots and small red wing spots, shifted to having even larger black spots and smaller red wing spots at sites where a congener with large red wing spots is numerically dominant (Hetaerina americana or Hetaerina occisa). Hetaerina americana showed the reverse pattern, shifting towards larger red wing spots where H. titia is numerically dominant. This pattern is consistent with the process of agonistic character displacement, but the ontogenetic basis of the shift remains to be demonstrated.

Genetic Variation and Population Structure of the Texas Tortoise, Gopherus berlandieri (Testudinidae), with Implications for Conservation

Abstract The Texas tortoise (Gopherus berlandieri) is a state-protected, threatened species in Texas. The expansion of agricultural practices and urban development are major causes of habitat degradation for the species. To provide genetic data that can inform conservation planning for this species, genetic variation, population structure, and the process that maintains the observed structure were examined in the Texas populations of G. berlandieri. Microsatellite genetic variation of 8 polymorphic loci was examined for a total of 138 individuals collected from 10 sampling areas in southern Texas. Assignment tests, F statistics, and analysis of molecular variance indicated that G. berlandieri forms weak population differentiation into northern and southern groups, with a boundary at southern Duval County. A test of isolation by distance and indirect estimation of the number of migrants (Nm) suggest recent gene flow between the 2 groups. Estimation of the extent of contemporary migration appears to be comp...

Comparative Digestion of Food Among Wildlife in Texas: Implications for Competition

Success in competition for a limited food resource can be determined in part by how efficiently a species digests food. We conducted in vivo trials to compare digestive performance by a guild of mast-consuming species in southern Texas: wild boar (Sus scrofa), white-tailed deer (Odocoileus virginianus), collared peccary (Pecari tajacu), wild turkey (Meleagris gallopavo), raccoon (Procyon lotor), and southern plains woodrat (Neotoma micropus). Four individuals of each species were fed commercial pellets and chromium-marked fiber to determine rates of passage. Dry matter and intake of digestible energy, and digestibility of detergent fiber, crude protein, and gross energy (metabolizability for turkeys) were determined for each species. Mean retention and time of passage of 95% of marked fiber were calculated. Digestibility and time of retention by wild boars was similar to foregut-fermenting species and equal to or greater than smaller hindgut fermenters. White-tailed deer and collared peccaries showed similar capabilities of digestion and retention, and also had higher digestibilities of fiber than small hindgut fermenters. Turkeys and raccoons had fast rates of passage and showed little digestion of fiber. Southern plains woodrats had intermediate digestibilities and times of retention. Wild boars are expected to be effective competitors for mast because of their digestive efficiency, large body size, and potential for consumption of large quantities of food.

The Genus EleodesEschscholtz (Coleoptera: Tenebrionidae) in Texas

False wireworms are larvae of the darkling beetle genus Eleodes Eschscholtz, some of which are agricultural pests of dryland wheat. Because of the large number of species in the genus (approximately 235), identifications can be problematic. Hence, regional keys are of great utility. Within the state of Texas a total of 31 species are known to occur: E. acutus, E. arcuatus, E. carbonarius, E. caudiferus, E. debilis, E. delicatus, E. dissimilis, E. easterlai, E. extricatus, E. fusiformis, E. goryi, E. gracilis, E. hispilabris, E. knullorum, E. labialis, E. longicollis, E. mirabilis, E. neomexicanus, E. nigrinus, E. obscurus, E. opacus, E. pedinoides, E. spiculiferus, E. spinipes, E. sponsus, E. striolatus, E. suturalis, E. tenuipes, E. tricostatus, E. veterator, and E. wenzeli. Herein we provide a key with illustrations and a brief diagnosis for the adult of each Texas species, along with notes on ecology, distribution, and pest status.

NewNotiodesSemiaquatic Weevil (Curculionidae) from Sporocarps ofMarsilea mollis(Marsileaceae) in Southern Arizona, USA

ABSTRACT. A new species from the semiaquatic weevil genus, Notiodes sporocarpicus , which develops and pupates in the sporocarps of the water fern Marsilea mollis B.L. Rob. & Fernald, is described from cattle tanks in southeastern Arizona. This new species can be separated readily from the majority of the known species by its nearly straight rostrum, with its distinctive dorsally swollen base and attenuated apex. Its elongate and slender body will separate N. sporocarpicus from most species in the genus except N. aeratus, which lacks the characters above. The Texas species N. celatus resembles the new species but has strongly developed suberect curved setae that are not present in N. sporocarpicus. Included are habitus photos and line drawings of the male and female genitalia of the new species.

Impact of Bothriocephalus acheilognathi (Cestoda: Pseudophyllidea) on Cyprinella lutrensis Condition and Reproduction

ABSTRACT Over 50% of imperiled fish species in Texas are endemic to the Rio Grande drainage. Bothriocephalus acheilognathi was recently collected from the Rio Grande and might pose further risk for these species. We examined the impact of this exotic tapeworm on fish condition and reproduction using a surrogate species, Cyprinella lutrensis. Fish were collected from two mainstem sites and one tributary site within Big Bend National Park from February through December 2006. Adjusted mean Fulton condition was higher for uninfected fish than infected fish. No differences were detected between uninfected fish for gonadosomatic indices, number of vitellogenic oocytes, number of late vitellogenic oocytes, late vitellogenic occyte maximum diameters, or proportion of late vitellogenic oocytes to total number of oocytes. These findings suggest that C. lutrensis is investing energy in reproduction at the expense of somatic growth, but energy invested in reproduction was not affected by tapeworm occurrence.

Mexican Long-tongued Bat (Choeronycteris mexicana) in El Paso, Texas

The Mexican long-tongued bat Choeronycteris mexicana is rare in Texas, as well as elsewhere in the United States and in Mexico. A C. mexicana was captured in December 2007 at a residence in El Paso, El Paso County, Texas. This is the first record of this species in western Texas.

Detection of Batrachochytrium dendrobatidis in Endemic Salamander Species from Central Texas

A nested PCR protocol was used to analyze five endemic salamander species from Central Texas for the presence of the emerging pathogen, chytrid fungus (Batrachochytrium dendrobatidis). Chytrid fungus was detected from samples of each of the five species sampled: with low abundance, in the Texas salamander (Eurycea neotenes) (1 positive out of 16 individuals tested; 1/16), the Blanco River Springs salamander (E. pterophila) (1/20), the threatened San Marcos salamander (E. nana) (1/17), and the endangered Barton Springs salamander (E. sosorum) (1/7); much higher abundance was obtained for the Jollyville Plateau salamander (E. tonkawae) (6/14), which has recently been petitioned for addition to the USA endangered species list. With one exception, sequences of PCR products were identical to the 5.8S rRNA gene, and nearly so for the flanking internal transcribed spacer (ITS) regions of B. dendrobatidis which confirmed the detection of chytrid fungus, and thus demonstrated the presence of this pathogen in populations of endangered species in Central Texas. These confirmations were obtained from nonconsumptive tail clippings which confirms the applicability of historically collected samples from other studies in the examination of the fungus across time.