Douglas-fir dwarf mistletoe (Arceuthobium douglasii) is a parasitic flowering plant that infects Douglas-fir (Pseudotsuga menziesii) throughout the western United States. Douglas-fir dwarf mistletoe induces the formation of witches' brooms on infected trees which alters the biomass and architecture of branches of the infected host. We obtained pairs of broomed and nonbroomed branches of Douglas-fir for sampling and comparing the communities of insects found in each type of branch. Twenty-five families were identified from branches of Douglas-fir, with Chrysomelidae, Phaleothripidae, Pteromalidae, and Braconidae being most common. Richness and totals of insects were one and a half to five times greater in witches' brooms than in nonbroomed branches, respectively. Significantly more Chrysomelidae, Phaleothripidae, Pteromalidae, Miridae, Berytidae, and Braconidae were found on broomed than on nonbroomed branches. However, no significant difference in the structure of the community based on relative abundance was found between broomed and nonbroomed branches. No species of insects was unique to either type of branch. This study represents the first to examine communities of insects in witches' brooms induced by Douglas-fir dwarf mistletoe.

Recovery efforts for the endangered ocelot (Leopardus pardalis) would be aided by knowledge of its feeding ecology in the affected region. We analyzed scat of ocelots and bobcats (Lynx rufus) from southern Texas. As has been found for most other populations of ocelots, rodents were the primary prey, but the principal species of rodent, the Mexican spiny pocket mouse (Liomys irroratus), is smaller than the principal prey reported for other populations of ocelots. Lagomorphs were more common prey than has been reported in other studies of ocelots, and birds more common prey than in all but one previous study. The diet of bobcats appeared similar overall to the diet of ocelots, but lagomorphs occurred in a significantly higher proportion of scats from bobcats. The data suggest that bobcats also preyed more heavily on the largest rodents and less on the medium-sized rodents than ocelots did. There was no clear division by type of habitat; both felids preyed approximately equally on species that are found primarily in grassland and those that are found in thornscrub. Near the United States-Mexico border, where the ranges of these felids overlap, there is the potential for substantial competition for resources between the two species. An important component of efforts to restore the population of ocelots in this region, therefore, will be a thorough investigation of this possibility. Studies of the dietary differences when both or only one of the felid species is present in an area, use of foraging habitat by both species, and the relationship between densities of prey and felids would allow the likelihood of negative impacts of competition to be fully evaluated.

The western yellow-billed cuckoo (Coccyzus americanus occidentalis) is a Distinct Population Segment that has been proposed for listing under the Endangered Species Act, yet very little is known about its spatial use on the breeding grounds. We implemented a study, using radio telemetry, of home range and use of habitat for breeding cuckoos along the Middle Rio Grande in central New Mexico in 2007 and 2008. Nine of 13 cuckoos were tracked for sufficient time to generate estimates of home range. Overall size of home ranges for the 2 years was 91 ha for a minimum-convex-polygon estimate and 62 ha for a 95%-kernel-home-range estimate. Home ranges varied considerably among individuals, highlighting variability in spatial use by cuckoos. Additionally, use of habitat differed between core areas and overall home ranges, but the differences were nonsignificant. Home ranges calculated for western yellow-billed cuckoos on the Middle Rio Grande are larger than those in other southwestern riparian areas. Based on calculated home ranges and availability of riparian habitat in the study area, we estimate that the study area is capable of supporting 82–99 nonoverlapping home ranges of cuckoos. Spatial data from this study should contribute to the understanding of the requirements of area and habitat of this species for management of resources and help facilitate recovery if a listing occurs.

In the southern Mexican Cueva del Azufre, a cave ecosystem with high concentrations of toxic hydrogen sulfide, one species of hemipteran (Belostoma cf. bakeri) has adopted a unique ecological function in that it acts as one of the top predators in the subterranean food web, preying on the abundant cavefish Poecilia mexicana. To date, several aspects of this predator-prey interaction have been explored, but basic questions related to the ecology of the waterbugs remained unstudied. We tested whether there is evidence for reproduction of waterbugs within the cave, which would indicate a self-sustaining population. Furthermore, we investigated the habitat affinities of different size-classes of waterbugs. We infer that waterbugs reproduce inside the cave despite the toxic properties of the water, as evidenced by the presence of nymphs of all sizes and males carrying developing zygotes. We also found size-dependent differences in use of habitat, and particularly small nymphs occupy different microhabitats than larger individuals. Adult waterbugs and large nymphs were most common at sites with cavefish. Small nymphs were rare at these locations, possibly to avoid cannibalism or exploit different resources in other locations. Furthermore, stable-isotope-analysis indicated that waterbugs likely derive their carbon from a combination of fish, dipteran larvae, and chemoautotropic bacteria.

Previous studies in central Arizona have shown that males of the bee Centris pallida fight for access to emerging receptive females and that larger males have greater mating success. Based on these results, larger-than-average males were predicted to be seen digging for emerging females, particularly if they were observed fighting with other males for control of a digging site. As predicted, larger-than-average males were captured while digging for emerging females. Although large males have consistently experienced an advantage over smaller ones in the competition for mates in a series of studies at this location beginning in the mid-1970s, smaller males continue to be the large majority of the male population.

Albuneid sand crabs are found in sandy beaches around the world, but little is known about the basic biology of any species in the family. We sampled sand crabs, Lepidopa benedicti, for 2 years at South Padre Island, Texas, at two locations: one developed site near the town, where recreational use is high and one undeveloped site away from the town, where recreational use is lower. We hypothesized that sand crabs would be less abundant and smaller at the developed site than at the undeveloped one. Densities were highest in summer and lowest in winter but did not differ between the two sites. There was no difference in size of individuals at the two locations. Females were significantly more common and larger than males. No ovigerous female was discovered at either location over 2 years of sampling. Individuals at South Padre Island are consistently smaller than those recorded from the northern Gulf of Mexico and Atlantic Ocean, suggesting the region might have habitat that is low quality for the species.

Oklahoma currently has 29 recognized species of crayfish. We introduce the thirtieth documented species, Cambarus ludovicianus, and use Maxent ecological niche modeling to predict potentially suitable habitat based on known distributions throughout its range. We used the Maxent algorithm with and without points of occurrence in Oklahoma to examine if the niche model predicts suitable habitat in Oklahoma where we found C. ludovicianus. Occurrences in Oklahoma were not predicted present based on the projection of the model using the previously known distribution of the species, except for the location of the Red Slough Wildlife Management Area in southeastern Oklahoma. However, including the new records in the model changes the predicted suitable habitat for the species in Oklahoma, encompassing all new locations and a large portion of eastern Oklahoma. We suggest that eastern Oklahoma and Texas represent the western edge of the range of C. ludovicianus. Further surveys in the field for C. ludovicianus at the limits of its range are required to understand detailed requirements of its habitat.

Carcasses of 11 medium-sized species of mammals along two-lane highways in northern Central Valley, California, were counted between 1997 and 2007 to obtain an indirect measure of changes in mammalian populations over time. Over this period, 1.23 mammalian carcasses were recorded per 100 km, lower than that reported in several other parts of North America. Each species was classified as human-sensitive, suburban-adaptable, or human-adapted according to the use of the land in which it was principally located. In contrast to simple predictions that populations of more human-sensitive species would be in decline and human-associated species would be increasing, indices of populations of all species showed little change once volume of traffic had been taken into account. Therefore, populations of most of the common mammals in the study area appear relatively stable at present. Annual fluctuations in populations of one species did not mirror those of other species of mammals suggesting that each species is a poor indicator of changes in populations of the other sympatric species of mammals.

Pitfall traps are widely used by researchers to survey a variety of terrestrial taxa. To test a method for improving the results of pitfall traps, we built a Y-shaped drift fence with six pitfall traps on each arm. We improved the pitfall traps by staking four pieces of aluminum flashing around each of the traps to increase their effective area. For experimental purposes, we used the aluminum flashing wings every other day. Traps without flashing caught a total of 395 reptiles and amphibians representing 15 species, and traps with the flashing caught a total of 624 reptiles and amphibians representing 20 species.

Reintroductions are increasingly utilized in conservation, but the experiences and environments to which animals are exposed prior to release can significantly impact the success of such efforts. We investigated differences in the diet of reintroduced juvenile alligator snapping turtles (Macrochelys temminckii) relative to juveniles from a wild population. In addition, we compared the diet of adult female Ouachita map turtles (Graptemys ouachitensis) to reintroduced M. temminckii with whom co-occurrence was recently reestablished and wild juvenile M. temminckii in a river system where the species have enjoyed long-term sympatry. There were differences in diversity and richness of the diet of M. temminckii at the two study sites that could be due to dissimilarity in foraging experience. There was greater overlap in diet of M. temminckii and G. ouachitensis at the site of reintroduction than at the site of long-term sympatry that corresponded to variation in composition of diet. Such a difference could indicate that partitioning of food resources has not taken place at the site of reintroduction to the degree that it has at the site with long-term sympatry.

Phrynosoma orbiculare is an endemic species of lizards in Mexico and is distributed from the northern part of the country to the central highlands. This species is found in open areas among scrubs, grasses, yuccas, and herbaceous plants. In our study, we performed two multivariate analyses (principal components and discriminant functions) to examine morphological and geographic variation among populations of P. orbiculare at the edge of the southern distribution of the species. Our assessment was to determine the taxonomic status of the subspecies Phrynosoma orbiculare orbiculare, P. o. cortezii, and P. o. boucardi described for this geographic zone. The analyses employed 10 informative diagnostic traits from digitalized images. Our results confirm only two subspecies, P. o. orbiculare and P. o. cortezii, in the study area. In addition, two new localities for the distribution of the species have been included (Nopalillo, Hidalgo, and Amealco, Queretaro). Moreover, the morphometrics of the organisms from new localities revealed that all individuals were positioned in the P. o. cortezii group and that the distribution of this subspecies extends west of the original records. We propose that the two populations reported as P. o. boucardi can be renamed as P. o. cortezii.

Museum specimens and literature records were used to determine the historical distribution and native status of redbelly dace in the Arkansas River Basin, Colorado. All specimens examined were southern redbelly dace (Chrosomus erythrogaster) and native status in the Arkansas River Basin was supported, in part, on the basis of a previously undiscovered specimen collected in 1913. Southern redbelly dace were documented in a geographically restricted area from near Canon City, Colorado, downstream to near Pueblo, and all locations were small tributary streams or off-channel ponds. The two remaining wild populations of southern redbelly dace in Colorado, and transplanted populations that originated from now extirpated populations, should be protected. Additional surveys should be conducted to determine if other populations exist in Colorado, which will better inform managers regarding future actions for the conservation of this species.

Male pallid bats (Antrozous pallidus) from the Purgatoire River Valley of northern Las Animas County, Colorado, were fitted with telemeters and followed to 53 day roosts. A majority of roosts were in cliffs (89%), with fewer in free-standing rocks at the base of cliffs. Temperatures at roosts were moderate (27°C) but warmer than ambient temperatures. Roosts in cliffs were slightly warmer than ambient temperatures, while roosts in rocks usually were 5°C greater than ambient temperatures. Typically, bats roosted in crevices that faced east or southeast with much solar exposure. Roosts in cliffs were in long, narrow cracks that extended into the face of the rock. The high temperatures recorded at roosts of male pallid bat may be advantageous for regulating body temperature, avoiding costly torpor bouts, or preparing for reproduction.

Larvae of the sawfly Neodiprion edulicolus fed on needles of Pinus edulis and were abundant below 1,850 m in elevation at sites near Sunset Crater, Arizona. Coleosporium needle rust, in contrast, infected P. edulis above 1,850 m in elevation and rarely occurred on the same trees as did N. edulicolus. Larval sawfly transferred to P. edulis above 1,850 m fed less frequently on infected twigs and moved off twigs more quickly when transferred to infected trees. Though the negative interactions involved only a small percentage of larval sawfly and rust fungus during this study, the interaction might become more significant in the future if sawflies spread to higher elevations in response to changes in climate or habitat.

We assessed predation on a threatened freshwater mussel, Potamilus amphichaenus, in the Sabine River in eastern Texas during the 2011 drought. We examined 79 recently deceased mussels, and 58 of these had signs indicating predation as the cause of death. This evidence and the absence of live specimens suggest that predation during low flow may contribute to the decline of P. amphichaenus.

We assessed the spatial and genetic organization of the island spotted skunk (Spilogale gracilis amphiala) on Santa Cruz Island, California. Home ranges of adults were largely non-overlapping, consistent with expectations for a solitary species. Contrary to expectations, we found no evidence of a matrilineal spatial structure. Relatedness of adult females was not negatively correlated with geographic distance, nor was it positively correlated with overlap of home ranges, possibly because of excessive dispersal caused by exceptionally high densities. We did find evidence of a patrilineal structure at one study site, where relatedness among males was negatively correlated with distance. The explanation for differences between males and females in genetic structure is uncertain, but it may reflect the differential influence of high density on dispersal of males and females.

In May 2009, we observed two male golden-cheeked warblers (Setophaga chrysoparia) feeding nestlings at the same nest. We determined the first male was the social mate of the female because we observed him closely following her during construction of the nest and the pair had already made a previous nesting attempt that breeding season. The second male was from a neighboring territory. Our observations demonstrate that cooperative breeding is an alternative mating strategy for this species. We hypothesize that this case of cooperative breeding resulted from an extrapair-copulation between the female and the second male during her fertile period.

The nests of nine Texas seaside sparrows (Ammodramus maritimus sennetti) collected from a mixed mangrove marsh on Mustang Island, Texas, were examined to determine details of the architecture and placement of nests. Nests were somewhat larger than those described for other seaside sparrow subspecies and were found higher off the ground. They were composed of woven dried grass and typically lacked a canopy. Placement of nests within the marsh seemed to be driven by proximity to the appropriate types of nesting materials in sufficient quantities.

The known distribution of the army ant Neivamyrmex texanus in the United States is limited to eight southern and western states. The range of N. texanus is extended to Oklahoma. Neivamyrmex texanus is the known host of only two symbionts. I report for the first time a parasitic phorid fly, Cremersia adunca, and include a brief description of the defensive behavior of the army ants to this aerial parasite.

While distributions of aquatic insects are fairly well known in the southwestern United States, relatively few surveys have been conducted in northwestern Mexico. We report new collections of species of aquatic Heteroptera in the region, which extend the known range of several species by hundreds of kilometers, including the first record of Graptocorixa emburyi in the United States, and help show that disjunct distributions of other species are more continuous than previously thought.

The largespring gambusia (Gambusia geiseri) is a livebearing fish likely endemic to the headwaters of the San Marcos River. This species thrives in cool headwater springs and, as a result of introductions for mosquito control, may now be invasive in many springs throughout Texas. Gambusia geiseri is believed to be outcompeting its endangered congener, G. nobilis, in the San Solomon Spring in western Texas and may be a threat to other endemic, spring-dwelling Gambusia. Thus, it is important to understand its current distribution. Approximately 15 years ago, the distribution of G. geiseri was documented through much of its range; however, many sites where G. geiseri occurs presently were not explored or were previously unknown. Therefore, to update the current distribution of this species in Texas, all sites previously documented, in addition to several other sites where G. geiseri now persists, were revisited. We present updated results for the distribution of G. geiseri in Texas and also provide estimates of the size of the population at each locale.

The dietary breadth of the western diamond-backed rattlesnake (Crotalus atrox) has been well documented; however, the relationship of species of prey and optimum energetic intake (e.g., size) is poorly understood. While lagomorphs have been documented as prey, their regularity in diets of C. atrox has not been examined. During several studies of C. atrox in Arizona, we collected dietary data through direct and indirect observation and analysis of scat. Lagomorphs were regularly included in the diet of adult C. atrox at all sites. Our observations suggest that C. atrox might select prey based on size to benefit from maximum energetic intake per feeding event.

Sexual dimorphism in the genus Sceloporus has historically been relatively well studied; however, there is little understanding of how patterns of sexual size dimorphism might vary within species and how that might affect our ability to generalize about the evolution of sexual size-dimorphism in Sceloporus and other organisms. We examined sexual size-dimorphism in a population of Sceloporus spinosus from Guadalcázar, San Luis Potosí, Mexico. Males (n = 85) and females (n = 63) showed no significant sexual dimorphism in size of the body, head, or legs. In combination with the results of other studies on sexual dimorphism in S. spinosus and closely related species of Sceloporus, our results suggest that there can be variation in sexual size-dimorphism within and among species that can limit the ability to make broad generalizations about the phylogenetic patterns of sexual dimorphism in Sceloporus.

Falco columbarius (merlin) was observed attacking and feeding on Tadarida brasiliensis (Mexican free-tailed bat) in downtown Abilene, Texas. The number of bats, time of emergence, the number of attacks by merlin, and success of merlin capturing bats were recorded. This study also documents techniques used by bats to avoid predation. To our knowledge, this study documents the first known predation of Mexican free-tailed bat by merlin and is one of the few that shows sustained predation on Mexican free-tailed bat by any species of bird of prey.

Bonytail, Gila elegans, in Cibola High Levee Pond, an isolated lower Colorado River backwater, fed more during evening and after dark than during daylight. Fish were omnivorous, and contents of stomachs (n = 72) included amorphous organic matter (materials digested beyond visual identification), aquatic macrophytes, invertebrates (micro-crustaceans, insects, and crayfish), bullfrog, and fish. Proportion of plants decreased while that of invertebrates increased with increased size of fish. Remains of fish were found only in the largest specimens. Asian tapeworm, Bothriocephalus acheilognathi, was in 11% of the sample and represents the first report for this parasite from open waters of the lower Colorado River system.