Note on mound architecture of the black-tailed praire dog

The development of black-tailed prairie dog ( Cynomys ludovicianus ) burrow mounds was monitored for three years. Entrances were flagged at points where a prairie dog was observed digging into the ground (primary entrances, n = 22) and digging out of the ground (secondary entrances, n = 8). In all samples it was observed that primary entrances became dome mounds and secondary entrances crater mounds. It is suggested that, although induced airflow (presently, a popular model) may partly explain the presence of mounds, architectural types (dome vs. crater mounds) are the result of energy constraints associated with building materials that differ at the entrances.     

Courtship behavior in Rhinoclemmys areolata from western Tabasco, Mexico (Testudines: Emydidae)

Observations in nature and captivity reveal that members of the population of Rhinoclemmys areolata of western Tabasco, Mexico, exhibit underwater courtship and mating and appear to lay one egg per nest.     

Selection of microhabitat by the red-backed vole, Clethrionomys gapperi

Clethrionomys gapperi were captured in microhabitats with greater densities of overall cover than at noncapture or random sites within the study area. Variables describing cover density and distance from free water were selected in a discriminant function analysis to differentiate between vole capture and noncapture sites. Vole capture sites had greater amounts of cover within 4 dm above ground surface and were further from standing water than noncapture sites. The preferential use by C. gapperi of microhabitats with greater densities of cover is in agreement with laboratory and field assessments of habitat use reported in the literature.     

Electrophoretic study of cutthroat trout populations in Utah

Thirty - nine Utah streams were sampled for cutthroat trout. Of these, 31 contain cutthroat or cutthroat / rainbow hybrid populations. By using starch gel electrophoresis, these populations were segregated into three groups. One group consisted predominately of fish from the Sevier River (of the Bonneville Basin) and Colorado drainages. A second was primarily populations from the Bear River Drainage (Bonneville Basin) as well as some scattered populations along the Wasatch Front (Bonneville Basin). The third consisted of Wasatch Front populations and populations that have hybridized with rainbow trout. Since different subspecies of cutthroat trout are native to the Colorado and Bonneville drainages, one would expect the populations from within the Bonneville Basin to be more similar to one another and less similar to the Colorado River populations. That this did not occur raises questions concerning the evolutionary relationships of the subspecies and the populations. It is clear that at least a northern (Bear River) and southern (Sevier River) form of the Bonneville cutthroat exists. The Wasatch Front may represent an intermediate zone where these two forms intergrade.         

Recovery of Gambel oak after fire in central Utah

The height of oak ( Quercus gambelii Nutt.) stems was measured on several fire scars within the Uinta National Forest and vicinity and compared with the height of oak stems on adjacent, nonburned areas. A significant relationship exists between the recovery rate of oak after fire and elevation, with the recovery rate being greatest at low elevations. A trend also exists showing that recovery tends to be greater on south to westerly exposures than on north to easterly exposures.     

Basidiomycetes that decay junipers in Arizona. II

Five additional species of wood rotting basidiomycetes on Arizona junipers are described and illustrated.   All cause a white rot of dead, fallen trees. Leptosporomyces juniperinus is proposed as a new species. Vararia fibra is reported from the United States for the first time.     

Evolutionary divergence in closely related populations of Mimulus guttatus (Scrophulariaceae)

The evolutionary divergence of five closely related populations of the yellow monkey flower. Mimulus guttatus was compared with the length of time the populations could have occupied the site and with the ability of the populations to intercross. Populations from the younger sites were found to be morphologically intermediate to populations from the older sites. Ability to intercross was not correlated with morphological divergence at this stage of evolution.       

Vascular flora of Kane Lake Cirque, Pioneer Mountains, Idaho

Kane Lake Cirque lies in the western Pioneer Mountains of south central Idaho. An inventory of the high elevation flora of the cirque revealed the presence of 180 vascular taxa representing 95 genera and 30 families. Five alpine taxa are here documented from Idaho for the first time: Carex incurviformis Mack., Draba fladnizensis Wilfen., Potentilla nivea L., Ranunculus gelidus Kar. & Kir., and Ranunculus pygmaeus Wahlenb. Kane Lake Cirque also contains populations of four additional alpine taxa considered to be of conservation concern in Idaho: Erigeron humilis Graham, Parnassia kotzebuei Cham., Saxifraga adscendens L., and Saxifraga cernua L.     

Mate sampling in a natural population of Pecos gambusia, Gambusia nobilis

Normal 0 false false false MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} Much research has been conducted on the mating systems of poeciliid fish in aquaria; however, there are fewer studies that examine mate sampling of these fish in the wild. In general, male poeciliids are characterized as being unselective in their mate choices and will attempt to copulate with seemingly all available females. Females are selective, copulate infrequently, and are often pursued by “ardent” males who may force copulations. To avoid male harassment, females in aquaria will often shelter from males among other females in shoals. Here, we examined the mate-sampling behaviors of male and female Pecos gambusia Gambusia nobilis by following individuals swimming in an outflow pool of Diamond Y Spring in southwestern Texas. In most cases, a male approached a solitary female, followed her briefly, and then left for no apparent reason. Approaching a number of females increased the likelihood that the male would follow one, and the longer a male followed a female, the more likely he was to copulate with her. As females were larger and faster than males, they could avoid males by swimming away from them. We found no evidence of the persistent males that harass seemingly unreceptive females as seen under aquarium conditions, nor did we see females join a shoal to stop pursuit by males. However, the activity of one male following a female did appear to attract other males who would compete to follow and attempt copulation. This competition might ensure that only superior males gain reproductive opportunities. Se han investigado extensamente los sistemas de apareamiento de pecílidos en acuario; no obstante, hay relativamente pocos estudios que examinan la elección de pareja de estos peces en su hábitat natural. Los pecílidos machos no suelen ser selectivos en su elección de pareja y parecen intentar copular con todas las hembras que estén a su alcance. Las hembras son selectivas, no copulan frecuentemente y a menudo las persiguen machos excitados que pueden copular con ellas forzadamente. Para evitar el acosamiento de los machos, en acuario las hembras a menudo se refugian de los machos entre otras hembras en bancos. Para este estudio, examinamos el comportamiento de elección de pareja de gambusias de pecos ( Gambusia nobilis ) machos y hembras al observar algunos individuos en un remanso del Diamond Y Spring en el suroeste de Texas. En la mayoría de los casos, el macho se acercaba a una hembra solitaria, la seguía brevemente y luego se alejaba sin motivo aparente. El acercarse a varias hembras aumentaba la probabilidad de que persiguiera a una de ellas, y cuanto más la seguía, más probable era que copulara con ella. Dado que las hembras son más grandes y más rápidas que los machos, podían eludirlos si no correspondían. No observamos machos persistentes que acosaran hembras aparentemente poco receptivas como se ha documentado en acuario, ni tampoco vimos hembras que se unieran a bancos para evitar la persecución de machos. Pero cuando un macho perseguía una hembra, parecía atraer otros, los cuales competían entre sí para seguirla e intentar copular con ella. Esta competencia podría garantizar que solo los machos superiores tengan oportunidades reproductivas.