Michelle L. Haynie

Parentage, multiple paternity, and breeding success in Gunnison's and Utah prairie dogs

Abstract Feasibility of assigning parentage using variable microsatellite loci was assessed for 2 species of prairie dogs. Parentage was determined from 7 microsatellite loci for 46% of juveniles born during 1994 in a colony of Gunnisons prairie dogs (Cynomys gunnisoni), and for 53% and for 45% of juveniles born during 1996 and 1997, respectively, in a colony of Utah prairie dogs (C. parvidens). Frequency of multiple paternity estimated for Gunnisons (77%) and Utah (71% and 90%) prairie dogs was greater than that detected previously for black-tailed prairie dogs (5%–10%) but within the range reported for other ground-dwelling squirrels. Of the 84 adult females and 33 adult males present during 1994 in the colony of Gunnisons prairie dogs, 75 (89%) and 22 (67%), respectively, produced weaned offspring. Breeding success for Utah prairie dogs was relatively low in 1996 (45% for females and 32% for males) but increased in 1997 (80% for females and 81% for males).

Diversity Among Tacaribe Serocomplex Viruses (Family Arenaviridae) Naturally Associated with the White-Throated Woodrat (Neotoma albigula) in the Southwestern United States

Bayesian analyses of glycoprotein precursor and nucleocapsid protein gene sequences indicated that arenaviruses naturally associated with white-throated woodrats in central Arizona are phylogenetically closely related to the Whitewater Arroyo virus prototype strain AV 9310135, which originally was isolated from a white-throated woodrat captured in northwestern New Mexico. Pairwise comparisons of glycoprotein precursor and nucleocapsid protein amino acid sequences revealed extensive diversity among arenaviruses isolated from white-throated woodrats captured in different counties in central Arizona and extensive diversity between these viruses and Whitewater Arroyo virus strain AV 9310135. It was concluded that the viruses isolated from the white-throated woodrats captured in Arizona represent 2 novel species (Big Brushy Tank virus and Tonto Creek virus) and that these species should be included with Whitewater Arroyo virus in a species complex within the Tacaribe serocomplex (family Arenaviridae, genus Arenavirus).

Mitochondrial DNA Variation in Pupfishes Assigned to the Species Cyprinodon macularius (Atherinomorpha: Cyprinodontidae): Taxonomic Implications and Conservation Genetics

Abstract Variation in mitochondrial DNA (mtDNA) was assessed in a captive stock and 11 wild populations (n = 259) from throughout the native range of Desert Pupfish Cyprinodon macularius as traditionally understood. Using PCR-SSCP, 18 composite haplotypes were identified from a 333-bp segment of the mitochondrial D-loop and two segments of the ND2 gene (333 and 325 bp). Representatives of each haplotype were sequenced for the entire ND2 gene and the 337-bp segment of the D-loop. Phylogenetic analyses revealed that haplotypes form two monophyletic groups, one in the Río Sonoyta/Quitobaquito Springs area and one in the Salton Sea/Colorado River Delta. This, with previous observations on morphology, color pattern, and geological history, supports recognition of the Río Sonoyta/Quitobaquito populations as a separate species, the Quitobaquito Pupfish C. eremus Miller and Fuiman, from the more widespread desert pupfish C. macularius Baird and Girard. More than 70% of mtDNA diversity across all populations was attributable to differences between the two species. Within species, the average local population contains 94% and 97% of the diversity in, respectively, C. eremus and C. macularius. Differences between the Salton Sea and Colorado River Delta populations of C. macularius explain a small (3.7%), but statistically significant, portion of mtDNA diversity in this species. This and the history of connections between Salton Sea and the delta suggest that the two regions should be managed separately with no intermixing of pupfish other than what occurs when the present, human-regulated hydrology is overcome by natural flooding. Haplotype frequencies in C. eremus from Quitobaquito Springs and Río Sonoyta were not significantly different. However, the potentially long history of isolation between these two populations and evidence of some degree of morphological divergence indicate a need for conservative management with no intermixing. The captive stock exhibited reduced mtDNA variation relative to its wild parent population from a locality on the delta. Variación de ADNmt fue examinado por una cepa de cautivo y 11 poblaciones silvestres (n = 259) de todas partes del rango natural del cachorrito del desierto Cyprinodon macularius como entendido tradicionalmente. Utilizando PCR-SSCP, 18 haplotipos compuestos fueron identificados desde un segmento de 337-pb del D-loop mitocondrial y dos segmentos del gene DN2 (333 pb y 325 pb). Representantes de cada haplotipo fueron sequenciados por el gene DN2 entero y el segmento de 337-pb del D-loop. Análisis filogenético mostró una relación monofilética reciproca entre poblaciones de dos regiones generales, Río Sonoyta/Quitobaquito y Salton Sea/Delta del Río Colorado. Esto, con observaciones previas de morfología, patrón de color, y la história geológica, sostiene el reconocimiento de las poblaciones de Río Sonoyta/Quitobaquito como una especie distinta, el cachorrito de Quitobaquito C. eremus Miller and Fuiman, de la especie con una distribución más amplia, el cachorrito del desierto C. macularius Baird and Girard. Más de 70% de la diversidad ADNmt de todas las poblaciones fue atribuida a diferencias entre las dos especies. Dentro de cada especie, la población promedia local contiene 94% y 97% de la diversidad de, respectivamente, C. eremus y C. macularius. Las diferencias entre las poblaciones de C. macularius del Salton Sea y las de la Delta del Río Colorado explican una pequeña (3.7%) pero una porción estadísticamente significativa de la diversidad ADNmt de esta especie. Esto y la historia de conecciones entre el Salton Sea y la delta sugieren que los dos regiones deben ser manejadas aparte sin mezclar a los cachorritos más que lo que ya ocurre cuando la hidrología actual controlada por los humanos, está conquistada por inundaciones naturales. Frequencias de los haplotipos en C. eremus del Quitobaquito Springs y el Río Sonoyta no fueron significativamente diferentes. No obstante, la historia probablemente larga del aislamiento de estas dos poblaciones y la evidencia de algún grado de divergencia morfológica indican la necesidad de un manejo conservativo sin mezclar las formas. La cepa a cautiva mostró variación reducida de ADNmt en relación a la de su población silvestre de orígin de una localidad en la delta.

RAPID RECOVERY OF RODENT POPULATIONS FOLLOWING SEVERE DROUGHT

Abstract Below normal precipitation during June 2001 through June 2002 was recorded at Chaparral Wildlife Management Area, near Catarina, Texas. This drought was followed by a 13-mo period (July 2002 through July 2003) of above average precipitation, providing an opportunity to examine the response of 5 species of rodents to drought conditions. Comparison of the number of unique individuals captured during the drought to the post-drought revealed a significant increase in the total number of individuals (approximately 500%) and in the number of individuals per species. A 3-mo lag time was observed between the end of the drought and the onset of population recovery. Although an increase in population size was anticipated as precipitation patterns returned to normal, the magnitude and rapidity of the recovery exceeded predictions and documented the resilience of rodents to adverse climatic conditions.

Unexpected high fitness payoff of subordinate social tactics in male collared lizards

Sexual selection theory often predicts that dominant males will sire more offspring than males displaying subordinate social tactics. We combined the records of space use by collared lizard, Crotaphytus collaris, females and records of social and spatial behaviour of males displaying two markedly different social tactics (territorial and nonterritorial) with genetic determination of parentage to test how variation in male social tactics influences the distribution of reproductive success. In marked contrast with predictions based on their social and spatial behaviour, territorial males did not monopolize paternity of offspring with the females that they defended, and on average, nonterritorial males obtained reproductive success equal to that of territorial males, both within and among successive clutches. When all males were analysed together, none of the traits that are often hypothesized to promote fitness in other lizards were under strong sexual selection in collared lizard males. Among territory owners alone, however, there was positive directional selection on body size. Both the unexpected success of nonterritorial males and exceptionally high levels of multiple paternity appear linked in part to features of the habitat at our study site that diminish the ecological potential for territorial males to monopolize mating opportunities with females that reside in their defended areas. If female collared lizards derive any fitness benefits by mating with multiple males, it is likely that these are genetic rather than material.

IMPLICATIONS OF HYBRIDIZATION BETWEEN WHITE-TAILED DEER AND MULE DEER

Abstract Frequency of interspecific hybridization between mule deer and white-tailed deer was investigated using ribosomal DNA and nucleotide sequences from the mitochondrial cytochrome b gene. Two of 15 individuals (collected by hunters) from northwestern Texas (Kent County) were identified as hybrids based on the ribosomal DNA marker. Sequence data from the cytochrome b gene indicated that 1 individual was the result of mating between a mule deer doe and a white-tailed deer buck, whereas the second individual resulted from mating between a white-tailed deer doe and a mule deer buck. These results indicate that hybridization between mule deer and white-tailed deer is not restricted to the Trans-Pecos region of Texas. Given the low levels of genetic divergence and frequency of hybridization, the validity of recognizing mule deer and white-tailed deer as distinct species is discussed. It is concluded that without the morphological and behavioral differences these 2 taxa could be considered subspecies rather than distinct species.

Diversity and phylogenetic relationships among the North American Tacaribe serocomplex viruses (Family Arenaviridae)

The purpose of this study was to extend our knowledge of the genetic diversity and phylogenetic relationships among the North American Tacaribe serocomplex viruses. Analyses of glycoprotein precursor gene sequence data separated the North American arenaviruses into 7 major phylogenetic groups. The results of analyses of Z gene and nucleocapsid protein gene sequence data were not remarkably different from the glycoprotein precursor gene tree. In contrast, the tree generated from RNA-dependent RNA polymerase gene sequences differed from the glycoprotein precursor gene tree with regard to phylogenetic relationships among the viruses associated with woodrats captured in the western United States, Texas, or northern Mexico. Further analyses of the polymerase gene sequence data set suggested that the difference in topology was a consequence of incongruence among the gene tree data sets or chance rather than genetic reassortment or recombination between arenaviruses.

Ecology of Catarina Virus (family Arenaviridae) in Southern Texas, 2001–2004

A total of 3941 rodents were captured during a 46-month prospective (mark-recapture) study on the ecology of Catarina virus in southern Texas. Antibody reactive against Catarina virus was found in 73 (11.9%) of 611 southern plains woodrats (Neotoma micropus) and none of 3330 other rodents; strains of Catarina virus were isolated from 6 antibody-negative and 9 antibody-positive southern plains woodrats; and the infections in at least 3 southern plains woodrats were chronic. These results affirm the notion that the southern plains woodrat is the principal host of Catarina virus and suggest that Catarina virus infection is highly specific to N. micropus.

Brownsville Common Yellowthroats Maintain Genetic Diversity in a Fragmented Landscape

Abstract Habitat fragmentation is particularly severe in the Lower Rio Grande Valley (LRGV) of Texas, where greater than 90% of the native wetland habitat has been replaced by agriculture and urban development. The Brownsville Common Yellowthroat (Geothlypis trichas insperata), a rare subspecies of the Common Yellowthroat restricted to this area, is a good model for studying the effects of this extensive fragmentation on avian genetics and ecology. In this study, three hypotheses addressing genetics and habitat fragmentation were tested: (1) the density of Brownsville Yellowthroats is greatest along the Rio Grande rather than away from the river; (2) individuals found on or near the Rio Grande are more closely related than individuals farther away; and (3) a source-sink metapopulation model is best fit to describe the population dynamics of this subspecies. We used 15 microsatellites to examine the genetic diversity of 128 individuals from Cameron and Hidalgo Counties (Texas) sampled during 2008–2009. The densities of yellowthroats at sites near the Rio Grande were not significantly different from densities at sites farther from the river. Genetic analysis indicated that individuals were as related to each other as would be expected in distant relatives and indicated the presence of a single, admixed population. The results suggest that the Brownsville Common Yellowthroat is able to move freely among isolated habitat patches and that wetlands along the Rio Grande do not act as an exclusive corridor for this species.

Trypanosoma cruzi in a Mexican Free-Tailed Bat (Tadarida brasiliensis) in Oklahoma, USA

Abstract: Trypanosoma cruzi is a vector-borne protozoan parasite that infects seven million individuals in Central and South America and is the etiologic agent of Chagas disease. There are increasing reports of endemic transmission within the southern US. Trypanosoma cruzi occurs in wild raccoons and dogs in Oklahoma, but its endemicity in the state is poorly studied. We suspected Mexican free-tailed bats (Tadarida brasiliensis) contributed to the endemicity of T. cruzi in Oklahoma due to their annual migration from Central America to their North American maternity roosts. During the summer of 2017, we sampled 361 Mexican free-tailed bats for T. cruzi at three maternity roosts in Oklahoma. We collected wing tissues, extracted T. cruzi DNA, amplified target DNA by PCR using the primers TCZ1/TCZ2, and observed amplification by gel electrophoresis. One juvenile Mexican free-tailed bat was positive for T. cruzi resulting in a 0.27% prevalence in the 361 sampled bats. Our finding of a wild bat naturally infected with T. cruzi in Oklahoma provided insight on the endemicity of T. cruzi in underrepresented endemic areas. The positive sample was sequenced, confirmed as T. cruzi, and uploaded to GenBank (no. MG869732). Future research will focus on monitoring T. cruzi prevalence in wild bats and insect vectors to better understand the enzootic emergence of this neglected tropical parasite.