On the relative importance of floral color, shape, and nectar rewards in attracting pollinators to Mimulus

Pollinator preferences were observed for the six species of section Erythranthe of the genus Mimulus using greenhouse-grown plants placed in a meadow in the Red Butte Canyon Natural Area, Salt Lake County, Utah. The principal pollinators were hummingbirds and bumble bees. Hummingbirds preferred the species with the most reflexed tubular flowers regardless of color, whereas bumblebees preferred pink. lavender, or yellow flowers to red flowers regardless of shape. Results for the six species were confirmed by observations of F 2 hybrid recombinant plants selected such that flower color could be held constant and flower shape varied and vice versa.     

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.       

Remarkable waxing, waning, and wandering of populations of Mimulus guttatus : an unexpected example of global warming

Experimental sets of Mimulus cardinalis and M. lewisii plants were (1) exposed to pollinators and (2) shielded from pollinators at study sties in Red Butte Canyon and Big Cottonwood Canyon, Wasatch Mountains, Utah. The exposed plants produced 1,535 seedlings and the shielded plants only 1. Clearly, seed production is dependent upon cross-pollination. A few syrphid flies were observed visiting the flowers but no hummingbirds or bumble bees, although the latter two have been reported as the main pollinators of M. cardinalis and M. lewisii , respectively. No interspecific hybrids were produced even though the species are fully interfertile, indicating that pollinators are faithful to their species or that different parts of their bodies pick up and carry pollen to the two different species.     

Plasticity and polymorphism in seed germination of Mimulus guttatus (Scrophulariaceae)

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* 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-priority:99; mso-style-qformat: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:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Seeds of 12 populations of Mimulus guttatus representative of the Wasatch Mountain ecotype were incubated for 17 months (one natural season plus a year) in five artificial climates found in phytotron studies to be important to the growth of the plants of that form of monkey flower. In all but the coldest climate, germination occurred promptly (3–8 days, on average), peaked during the first three weeks, and then tapered off gradually well into the second season. Generally, the amount and timing of germination was plastic, showing much the same range of responses in widely different climates both overall and for individual populations. However, in some cases, there were significant differences between populations indicative of polymorphism within the species. For example, germination was significantly slower, more variable, and less in amount the higher the elevation of origin of the populations. The responses of the population suggest the presence of both much plasticity and much polymorphism for germination characteristics in this form of M. guttatus.     

The pattern of esterase variation in the Mimulus glabratus complex (Scrophulariaceae)

Disc gel electrophoretic assays of Mimulus plants showed young stems to contain at least 15 esterase bands. The 6 bands in the center of the gels were highly reproducible. Eighty-one populations representative of all the cytotaxonomic groups and of the Western Hemisphere geographic range of the Mimulus glabratus complex were assayed for those 6 bands. There was no apparent correlation between the distribution of the esterase bands and important environmental parameters such as elevation and latitude. Hence, their distribution did not appear to reflect environmental adaptive values. Each population was monophonic for its particular combination and intensity of esterase bands which is consistent with our previous suggestion that genetic drift is a strong component of the evolutionary pattern of the complex.     

Diversity and nectar hosts of flower-settling moths within a Florida sandhill ecosystem

The purpose of this study was to document and identify flower-settling moths within a Florida sandhill ecosystem and investigate their potential pollination capabilities. A combination of methods incorporating observation, morphology, pollen analysis and behaviour were applied. Fifty-two species of moths were documented taking nectar on flowers. A novel nectar-feeding behaviour categorized as fluttering resulted in increased pollen collection. Significant morphological match of moth proboscis length with flower corolla length was found. A preliminary list of sandhill moths is presented, and a pollen library of flowers found throughout the study area was created. This study was the first to conduct observations of settling moths in upland pine communities, and offers a rare glimpse into the interactions of moths with flowers within a unique ecosystem.     

Pollinator preferences for yellow, orange, and red flowers of Mimulus verbenaceus and M. Cardinalis

Red. orange, and yellow morphs of Mimulus verbenaceus and M. cardinalis were field tested for pollinator preferences. The species are closely similar except that M. verbenaceus flowers have partially reflexed corolla lobes, whereas M. cardinalis flowers have fully reflexed corolla lobes. On the basis of over 6000 bumblebee and hummingbird visits, highly significant ( p Mimulus verbenaceus and M. cardinalis .     

Use of radio transmitter implants in wild canids

Twelve adult and five juvenile coyotes and 20 adult kit foxes were implanted with radio transmitters using relatively simple surgical procedures. Four foxes were successfully implanted in the field. None of the animals implanted exhibited noticeable behavioral effects, and no deaths were confirmed to result from implantation. Implants were attached to the peritoneum in adult coyotes and kit foxes and were left free - floating within the abdominal cavity of the coyote pups. Both procedures produced satisfactory results. Radio signals transmitted from implants had less range than those from traditional neck collar transmitters. Implants offered benefits unavailable with traditional collar transmitters: no external packaging to influence behavior, ability to radio monitor small or juvenile animals, and ability to acquire various physiological data on free - ranging individuals.         

Survivorship and cause-specific mortality in five populations of mule deer

We used retrospective analyses to investigate cause-specific mortality and survivorship among 5 populations of mule deer ( N = 168 telemetered animals) wintering in the western Great Basin during 1986-1994. These populations existed under similar environmental conditions, but survivorship functions differed among them. Monthly survival ranged from 0.964 to 0.990, and annual survival ranged from 0.643 to 0.884. The proportion of deaths attributed to predation and malnutrition or anthropogenic causes did not differ among the 5 populations. Predation was the leading cause of mortality; mountain lions were responsible for approximately 90% of the deer killed by predators. No difference existed among these populations in the proportion of telemetered deer that were killed by mountain lions, but proportionally more females than males were killed by these large fields. Predation by mountain lions is the primary source of mortality and a widespread phenomenon among the populations of mule deer we investigated.     

Multiple ectopic limbs in a wild population of Hyla regilla

A wild population of Pacific tree frogs ( Hyla regilla ) in Idaho exhibited a high incidence (22%) of hind limb abnormalities. This situation is discussed with reference to similar occurrences reported for isolated populations of the species in the Pacific Northwest.         

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.         

Carbon isotope discrimination and water relations of oak hybrid populations in southwestern Utah

The evergreen oak Quercus turbinella and the deciduous Q. gambelii form natural hybrids in southwestern Utah and northern Arizona. Hybrid individuals also are found in northern Utah in a region where only Q. gambelii currently exists, indicating that Q. turbinella has recently retreated southward. Our objectives were to (1) examine the ecophysiology of parental taxa and hybrids under natural conditions in southeastern Utah, and (2) investigate the level of integration between leaf carbon isotope discrimination (a synthetic gas exchange trait) and structural and chemical traits of leaves in morphologically variable hybrid populations. Leaf length, width, mass-to-area ratio (LMA, g m -2 ), and nitrogen concentration (N, g g -1 ) within 2 hybrid populations near New Harmony, Utah, were highly intercorrelated. Variation within the hybrid populations spanned mean values for these traits observed in parental taxa from adjacent ""pure"" populations of each species. Carbon isotope discrimination (Δ), an integrated measure of the ratio of intercellular to ambient CO 2 concentration, ranged from 16.1‰ to 19.6‰ within the 2 hybrid populations and was positively correlated with leaf nitrogen concentration and negatively correlated with LMA; individuals in hybrid populations with leaves resembling Q. gambelii had the highest leaf Δ and N concentrations and lowest LMA compared with leaves from plants that resembled Q. turbinella . CO 2 uptake is limited by stomatal conductance and possibly by mesophyll resistance to a greater extent in Q. turbinella phenotypes than in intermediate or Q. gambelii phenotypes. δD of stem xylem water (an indication of active rooting depth) and predawn water potential during the peak monsoon period in August were not correlated to leaf Δ values within the hybrid populations. Several individuals that were morphologically similar to Q. turbinella in the hybrid populations maintained high predawn water potentials and derived moisture from winter recharge that presumably was taken from deep soil layers. Apparently, a few adult individuals of the Q. turbinella phenotype in hybrid populations accessed water from deep in the soil profile, which enabled them to avoid summer drought. Reduced monsoonal activity may have been an important, but not the single, determinant of Q. turbinella s retreat from northern Utah during the recent Holocene.     

Annotated inventory of invertebrate populations of an alpine lake and stream chain in Colorado

Benthic macroinvertebrates were collected during the ice-free season (1 July-20 October) over a five-year period from a chain of alpine lakes and intervening streams in the Green Lakes Valley (3,347-3,615 m) in Boulder County, Colorado. A list of taxa was developed for 1981 and 1982, with taxonomic additions for 1983- 1985 and comments on community structure, seasonal and elevational changes in species abundance, and noteworthy occurrences. A total of 111 taxa was collected, of which 84% occurred in streams, 58% being exclusively lotic. Dipterans composed 73-81% of total abundance in streams. The littoral benthic zone of lakes was predominantly trichopterans and dipterans, 44-60% and 24-39%, respectively. Numerically important organisms in various lakes and streams were chironomids, simuliids (particularly Metacnephia ), oligochaetes, and the bivalve Pisidium casertanum . An isolated lake and its outlet stream, with unique characteristics, were the sole locations of Gammarus lacustris (Amphipoda) and Glossiphonia complanata (Hirudinea). Manipulated lowering of a lake along the main drainage exposed abundant and luxuriant colonies of the bryozoan Fredericella sultana . This organism was found on 43% of all rocks sampled, a preponderance heretofore unknown for this, or any, ectoproct in alpine or arctic lakes.     

Comparison of reproductive timing to snow conditions in wild onions and White-crowned Sparrows at high altitude

Timing of reproduction was assessed for wild onions and White-crowned Sparrows in relation to snow conditions on the same subalpine meadow in the Sierra Nevada for 21 years. Flowering date and clutch initiation date were both highly correlated with snow conditions, being later as snowpack was deeper. Interannual variation in schedule was 46 days for onions and 33 days for sparrows. There was nearly a fivefold difference in snowpack depth, and date of snow disappearance varied interannually by 72 days. Compensation for late-lying snows occurred in both species but was greater in sparrows than in onions because the nest-building behavior of sparrows was flexible. In years of deeper snow, sparrows were able to lay eggs earlier because they built more nests than usual in trees and shrubs rather than waiting for groundcover to develop.     

Patterns of asymmetry in body traits and genitalia in two distant populations of a Neotropical scorpion

The ability of a genotype to control the stable development of a phenotype under different environmental conditions may explain the level of developmental instability. An indicator to developmental instability is Fluctuating Asymmetry. Traits under pressures of sexual selection exhibit greater values of asymmetry that others. These traits have more physiological requirements during morphogenesis and a more complex development. The aims of this work are to analyze asymmetry patterns of genitalic and somatic traits in the scorpion Bothriurus bonariensis (Bothriuridae) and to compare these values between central and peripheral populations of its distribution. We observed that types of asymmetry in genitalic traits differed in both populations. Also, traits of the hemispermatophores (two halves that constitute the spermatophore) showed the highest levels of fluctuating asymmetry, particularly in those characteristics with important role for insemination success. This work offers fundamental baseline knowledge for further works focused on asymmetry of genitalia and mating success in scorpions.     

Spider fauna of selected wild sunflower species sites in the southwest United States

Normal 0 false false false EN-US X-NONE X-NONE 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-priority:99; mso-style-qformat: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:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Fifteen genera representing nine families of spiders were collected in the southwestern United States in 1980. Thomisidae, Araneidae, Dictynidae, and Salticidae were the most commonly collected spider families. Ten genera of spiders not previously reported on sunflowers are reported for the first time.     

Dynamics of rodent populations in semiarid habitats in Lassen County, California

From 1996 to 2004, we studied population dynamics of a rodent assemblage in semiarid habitats in Lassen County, California. Abundances of rodents appeared affected by fluctuations in precipitation from a high in 1996 to average and slightly below-average levels in subsequent years; perhaps reflecting this, assemblage composition also changed dramatically during the study period. California kangaroo rats ( Dipodomys californicus ) declined from abundant to extremely rare, abundances of deer mice ( Peromyscus maniculatus ) fluctuated greatly during the study period, and, perhaps most notably, populations of dusky-footed woodrats ( Neotoma fuscipes ) appeared to decline to local extinction, possibly allowing for the subsequent colonization of desert woodrats ( N. lepida ). These changes appeared to represent natural variation in numbers and composition in an ecologically dynamic ecotonal region in response to multiyear changes in precipitation.     

Reproductive pattern in the southernmost populations of South American redbelly toads

Anurans can be classified as explosive or prolonged breeders. In species with short breeding periods, intensive competition for females is expected. We analyse the temporal breeding pattern of Melanophryniscus aff. montevidensis, a bufonid inhabiting grasslands of Argentina, whose breeding is concentrated in events of short duration. Males are active during more than one breeding event per season, whereas most females take part in a single event per season. Active males outnumbered females by up to 14 times at one event, operational sex ratio (OSR) ranged from 0.07 to 0.75 and intensity of sexual selection (I _s) from 0.69 to 24. We found a negative association between I _s and OSR, but no correlation between number of active males per event and OSR or I _s. The OSR is the key that regulates the intensity of sexual selection, nevertheless, and in spite of being explosive breeders, females would potentially have chances to select their mate.     

Demographic characteristics of American marten populations in Jackson Hole, Wyoming

Some American marten population characteristics (numbers, density, body weights, sex and age ratios, natality, mortality-survivorship, immigration-emigration, home ranges) were studied at four sites in the southern part of the Greater Yellowstone Ecosystem, Teton County, Wyoming, in 1975-1979. Ninety-eight different martens were examined. Males (n = 25) weighed 1,111 g (± 110 SD, range 875-1,235), whereas females (n = 17) averaged 743 g (± 83 SD, range 600-900). Live-trapping showed sex ratios of 1.5M:1.0F, whereas carcasses showed 3.0M:1.0F. Of 27males that were aged, 12 (44%) were less than 1 year old and 2 were 9-10 years old. Of 10 females, 6 were less than 1 year old and 1 was 12-13 years old. The mean length of time a male was present on the major study area was 144 days (± 266 SD, range 1-1,364), and for females it was 145 days (± 45 SD, range 1-560). Home ranges for six males averaged 3.2 km 2 (± 20 SD, range 0.7-5.8) on the main study area. Some management implications are given.