Comparative life history and floral characteristics of desert and mountain floras in Utah

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;} Life forms and floral characteristics of plants at Arches National Park (desert communities), the Mt. Nebo complex, and a subalpine meadow in the Uinta Mountains (montane and subalpine communities) were compared. Characteristics observed were (1) life form, (2) longevity, (3) pollination system, (4) flower structure, (5) flower symmetry, and (6) flower color. Common families in each flora were also compared. Results showed that there is a significant overrepresentation of shrub species at Arches, and an underrepresentation of perennial forbs. Relative number of perennial forb species was significantly higher at Mt. Nebo and the subalpine meadow than at Arches National Park. Native annuals and wind-pollinated species were significantly overrepresented at Arches. Flowers with open structure that permit free access of most insects to nectar and pollen were overrepresented at Mt. Nebo and in the subalpine meadow. The distribution of flower colors also differs significantly among these ecologically contrasting floras, with yellow being best represented in the desert and white in the mountains.       

Pollination needs of arrowleaf balsamroot, Balsamorhiza sagittata (Heliantheae: Asteraceae)

Arrowleaf balsamroot, Balsamorhiza sagittata (Pursh) Nutt, is a common, sometimes dominant, longlived forb that flowers early in spring from the foothills to upper-montane areas of the northern Rocky Mountains and Intermountain West. Public land managers desire its seed for rangeland rehabilitation. Through manual pollination field trials, the species was found to have a mixed pollination system. It is primarily xenogamous (46% of ovules yielded plump achenes) but partially self-compatible (31% of achenes were plump). Unvisited flower heads formed virtually no mature achenes; only plump achenes contained seeds with endosperm. Freely visited flower heads in 2 populations produced as many achenes as manual outcross pollinations of flower heads, suggesting that seed production was not pollinator limited. Two species of Osmia bees rely mostly on Balsamorhiza and its close relative, Wyethia , for pollen. At least 165 females per hectare will need to be stocked to achieve thorough flower visitation in cultivated seed production fields.     

Bee visitors of sweetvetch, Hedysarum boreale boreale (Leguminosae), and their pollen-collecting activities

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;} The native bee fauna visiting and pollinating a population of sweetvetch in Grand Teton National Park was surveyed. The papilionaceous flowers were exploited by 37 bee species, most of which had long mouthparts. Most species collected pollen as well as nectar. Bees foraged most heavily in early afternoon when pollen was most abundant. However, there was no indication that bee species were competing for limited pollen resources: there was no difference among three time periods in percent sweetvetch pollen carried in the scopal pollen loads of bees nor was there any evidence that some species were displacing the foraging times of others. The advantages of developing a native species as a commercial pollinator of sweetvetch are discussed and several potential candidates are mentioned.     

Insect-mediated pollination in slickspot peppergrass, Lepidium papilliferum L. (Brassicaceae), and its implications for population viability

Field experiments on the pollination biology of slickspot peppergrass, Lepidium papilliferum L. (Brassicaceae), a rare species endemic to microsites in sagebrush-steppe habitat in southwestern Idaho, were conducted at 2 sites from May to July 2001. Site KB contained over 10,000 plants, whereas site WG contained less than 150 plants. Insect exclusion experiments revealed that seed production in L. papilliferum is dependent on insect-mediated pollination; median percent seed set dropped from 70% to 2% when insects were excluded from flowers. A total of 25 insect families from 5 orders visited L. papilliferum flowers: 24 families at KB and 11 families at WG. Only 9 families contained more than trace amounts of pollen on their bodies: Hymenoptera-Anthophoridae, Apidae, Colletidae, Halictidae, Sphecidae, Vespidae; Coleoptera-Cerambycidae, Dermestidae; Diptera-Syrphidae. Insects from these families are likely responsible for pollination of L. papilliferum , although some may be of only minor significance due to their infrequent visits to flowers. Two of the 4 most common and pollen-laden insects found at KB, honey bees ( Apis mellifera ) and colletid bees, were absent or rare at WG. Three other pollen-carrying families present at KB, Sphecidae, Vespidae, and Halictidae, were not found at WG. We raise several possible explanations for this disparity in pollinator communities between sites and discuss the importance of pollinator diversity to the long term viability of L. papilliferum .     

Effects of defoliation on reproduction of a toxic range plant, Zigadenus paniculatus

Zigadenus paniculatus is a toxic plant common on sagebrush foothills at middle elevations in the western United States. Plants produce several racemes from a single stalk. Flowering commences at the base of each raceme and proceeds upwards. The terminal raceme begins blooming first and is followed by lower racemes in sequential order. Flowers are markedly protandrous and incapable of autogamy. Observations do not support the idea that apomixis is a viable reproductive strategy. Plants are mostly self-incompatible; a few seeds were produced from geitonogamous hand pollinations. The pollen/ovule ratio was high, also suggesting outcrossing as the predominant mode of sexual reproduction. A self-incompatibility mechanism may have evolved because the movements of syrphid flies on the inflorescence render protandry alone insufficient to prevent some selfing. The probable presence of toxic substances in the pollen and nectar appears to have reduced the number of potential pollinator species but increased the flower constancy of those species capable of utilizing the floral rewards.     

Saproxylic beetles (Coleoptera) and hoverflies (Diptera: Syrphidae) from a Mediterranean forest: towards a better understanding of their biology for species conservation

This report represents the first integrative study on saproxylic Coleoptera and Diptera Syrphidae from a representative Mediterranean forest in Cabañeros National Park in Central Spain. We collected 107 beetles, representing 32 families, and 25 species of hoverfly. Two undescribed and numerous rare beetle species were recorded, as were four hoverflies considered to be threatened species in Europe. We compiled biological information for all of the taxa encountered and recorded new data on their feeding habits, breeding microsites, and known tree associations. We found that the saproxylic biodiversity in this National Park was characterized by a significant number of Central European and North African species. Our results on the saproxylic assemblage, comprising many rare and poorly known species, of a typical Mediterranean forest represent a first step toward improved understanding of the saproxylic community and establishing the basis for conservation strategies in this region.     

Notes on the reproductive biology of Zigadenus paniculatus, a toxic range plant

Zigadenus paniculatus is a toxic plant common on sagebrush foothills at middle elevations in the western United States. Plants produce several racemes from a single stalk. Flowering commences at the base of each raceme and proceeds upwards. The terminal raceme begins blooming first and is followed by lower racemes in sequential order. Flowers are markedly protandrous and incapable of autogamy. Observations do not support the idea that apomixis is a viable reproductive strategy. Plants are mostly self-incompatible; a few seeds were produced from geitonogamous hand pollinations. The pollen/ovule ratio was high, also suggesting outcrossing as the predominant mode of sexual reproduction. A self-incompatibility mechanism may have evolved because the movements of syrphid flies on the inflorescence render protandry alone insufficient to prevent some selfing. The probable presence of toxic substances in the pollen and nectar appears to have reduced the number of potential pollinator species but increased the flower constancy of those species capable of utilizing the floral rewards.     

Reproductive biology, hybridization and flower visitors of rare Sclerocactus taxa in Utah's Uintah Basin

We studied the mating system and flower visitors of 2 threatened species of Sclerocactus (Cactaceae) in the Uintah Basin of eastern Utah—an area undergoing rapid energy development. We found that both S. wetlandicus and S. brevispinus are predominantly outcrossed and are essentially self-incompatible. A third presumptive taxon (undescribed; here called S. wetlandicus -var1) is fully self-compatible but cannot produce seeds unless the flowers are visited by pollinators. We found tentative evidence for pollinator limitation of fruit set in S. brevispinus but not in the other taxa. Pollinators are largely species of native ground-nesting bees in the subfamily Halictinae. These bees are indiscriminate collectors of pollen and nectar from Sclerocactus flowers and other plant species. The well-being of Sclerocactus populations requires that land managers ensure the preservation of halictid bee habitat, which includes both nesting sites and a diversity of floral resources. These bees are also undoubtedly the pollen vectors responsible for the production of hybrids in areas where S. wetlandicus and S. brevispinus meet. We experimentally confirmed that reciprocal crosses between S. wetlandicus and S. brevispinus are indistinguishable from each other or from pure crosses in fruits/flower, seeds/fruit and seed weights. We suggest that hybridization preceded energy development, that it attests to the ongoing process of evolution in the Sclerocactus group, and that it should not be suppressed by anthropogenic activity.     

Habitat and diet of Bhutan takin Budorcas taxicolor whitei during summer in Jigme Dorji National Park,Bhutan

Little is known about the ecology of the rare and vulnerable Bhutan takin Budorcas taxicolor whitei, a large and basically forest-dwelling goat-antelope inhabiting mountain valleys in northern Bhutan. In Tsharijathang valley (3800 m asl) in Jigme Dorji National Park, we described the summer habitat of this takin subspecies through vegetation transects and by studying diet via microhistological analysis of faeces supplemented by examination of feeding sites. The habitats utilized by the c.250 animals occupying the valley consisted of six main vegetation types with roughly equal coverages, viz. three forest types (dominated by Juniperus, Betula or Abies), alpine scrub (mainly low Rhododendron shrubs), open alpine meadow (mainly graminoids and forbs) and semi-open willow shrub (mainly Salix and forbs). Sixty-eight food species were identified in the feeding sites, but the bulk of the diet consisted of ≈10 species, the same species that also dominated the faecal material. With >50% of the diet consisting of shrubs, mainly Salix myrtillacea, the takins were mainly browsers. When foraging, they exhibited a weak form of selection by choosing sites with a slightly higher coverage of the most important food species and, while at these, proportionally more feeding signs were recorded. Domestic yak Bos grunniens are allowed to graze in the study area during winter when the takins have descended to lower elevation. At the present grazing pressure, the wintering yaks probably benefit the takin by maintaining the open vegetation structure, but their numbers and impact on the habitat should be monitored to prevent adverse effects.     

The nesting habits and flower relationships of the bee Melitoma ameghinoi (Holmberg) (Hymenoptera,Apidae), with notes on its taxonomy and distribution

ABSTRACT

The nesting behaviour of Melitoma ameghinoi was studied in the province of Chaco, Argentina. Contrary to other Melitoma species, which are known to nest on banks or other vertical or sloping surfaces, the nests were found on horizontal ground, in extremely hard clay soil. The nests were shallow, with three to four vertical cells. The short turrets pointed upwards for a short stretch and then were strongly curved, with the entrance directed towards the soil surface. The floral relationships of this species were studied by pollen analysis of faeces from cells, a pollen mass, scopal loads of specimens, and direct observation of floral visits. Pollen counts and field observations indicate that M. ameghinoi collects pollen exclusively from Ipomoea species. A compilation of pollen sources for species of Melitoma is presented. All known species, including M. ameghinoi, fall in the category of narrowly oligolectic. A discussion of the taxonomic relationships of the species is presented, and a lectotype is designated.     

Natural history of the African riverine tiger beetle Chaetodera regalis (Dejean) (Coleoptera: Cicindelidae)

The tiger beetle Chaetodera regalis (Dejean) (Coleoptera: Cicindelidae) is widely distributed throughout sub-Saharan Africa. We studied activity patterns, ecological interactions, and behaviour of this species along four major rivers in Kruger National Park, South Africa. During the dry season, small numbers of adult beetles are found on sand bars along perennial rivers. In the rainy season, adults are found in large numbers on a broad spectrum of substrates (including clays, coarse and fine sands and gravels, and black organic soils) and geomorphological features (sand flats, mud flats, sand bars, beaches, riverbanks, and dry and wet sandy streambeds) in riverine areas. Predatory, defensive, thermoregulatory, and reproductive behaviours are described. This species may prove to be a useful indicator of the health of African riverine systems: adults are abundant in high-quality riverine areas; adults and larvae may be adversely affected by human activities; and adults are easily detected, even by novice surveyors.     

Grass spider microhabitat use in Organ Pipe Cactus National Monument, Arizona

The grass spider ( Agelena naevia ), commonly found in Organ Pipe Cactus National Monument, Arizona, uses rodent burrows located under a shrub canopy more frequently for web construction than burrows located in the open. The average number of prey available in canopy microhabitat was greater than in open microhabitat, and unequal prey abundance may explain spider microhabitat use.        

Time-lapse photography reveals the occurrence of unexpected bee-pollination in Calanthe izuinsularis,an endangered orchid endemic to the Izu archipelago

Calanthe izuinsularis is a rare, beautiful and fragrant orchid endemic to the Izu archipelago. Although it is known that mainland populations of closely related Calanthe species are pollinated by medium- to large-sized bees, it is likely that C. izuinsularis has been forced to alter its floral biology to attract alternative pollinators, as large-sized bees are rarely found on the Izu Islands. Indeed, the unusual floral characteristics of C. izuinsularis, which produces pale flowers that emit a strong and fragrant scent during the night, are considered the adaptation to a moth-pollinator syndrome. As expected, our time-lapse photography using a digital camera revealed that the inflorescences of C. izuinsularis were most frequently visited by nocturnal moths such as Noctuidae, Geometridae and Crambidae, which accounted for 50% of all insect visits (in terms of both the number of frames with captured visitors and the number of times visited). However, our study could not provide evidence of a pollinator shift towards moths because none of the moth species was observed with pollinaria. On the other hand, our study found that the pollinaria of C. izuinsularis could become attached to the mesothorax of the small-sized sweat bee Lasioglossum occidens. Therefore, our study suggests that C. izuinsularis is still somewhat dependent on bee pollination, while the orchid has changed its floral colouration and scent. The occurrence of bee-pollination in C. izuinsularis would provide an explanation for how the natural hybridisation between C. aristulifera, C. discolor and C. izuinsularis can occur.     

Larval food sources of Centris (Heterocentris) analis (Fabricius, 1804) (Hymenoptera: Apidae), an oil-collecting bee

Pollen analysis of larval food allows identification of plants used as nest provision sources. Considering the importance of Centris analis in pollination, we aimed to identify its plant sources, food niche width in Cerrado, and analyze the use of sources between cool/dry and warm/wet seasons. We sampled 22 nests collected in two areas from February 2008 to October 2009. Heteropterys spp. (Malpighiaceae) were the main pollen sources, but Byrsomia spp. (Malpighiaceae), Banisteriopsis malifolia (Malpighiaceae), Solanum lycocarpum (Solanaceae) and Machaerium spp. (Leguminosae) were also important food sources. There was no difference in the use of the sources between the seasons (F_1,100?=?0.001; p?=?0.979). Despite the high number of pollen types (n?=?14) the food niche widths were low, H?=?0.777 and H?=?0.949, which can be explained by the dominance of some food items. Hence, C. analis use, profusely, a few plants as food sources that could be considered conservation targets.     

Pinyon-juniper woodlands in Zion National Park, Utah

Juniperus osteosperma-Pinus monophylla or P. edulis (P-J) woodlands are the most widespread plant community in Zion National Park (ZNP), southwestern Utah. These woodlands dominate nearly half of the park's land area. Our study of this vegetational complex is based on a sample consisting of 115 macroplots (each 0.01 ha in area) objectively distributed across the entire area of ZNP. We recognize 3 subtypes within the P-J complex: Juniperus osteosperma (Utah juniper) alone, juniper with P. monophylla (single-leaf pinyon), and juniper with P. edulis (two-leaf pinyon). The 2 pinyon pines rarely occur together, and thus the foregoing subtypes do not overlap geographically to a significant extent. The first 2 subtypes occur primarily below 1800 m elevation, while the latter is most commonly found above that elevation. Because of the scarcity of sizable expanses (over ～ 10 ha) of well-developed soils in ZNP, the P-J complex occurs primarily on sites where exposed bedrock covers a large portion of the habitat. As a result, over 90% of stands assigned to the P-J complex support less than 50% tree canopy cover (64% have less than 25% tree cover). Shrub cover increases along the woodland successional gradient. Pinyon cover increases faster than juniper cover. Microbiotic soil crust cover is consistently greater in J. osteosperma-P. monophylla woodlands than in J. osteosperma-P. edulis woodlands, but total living cover increases significantly along the successional gradient in both communities. To enhance plant and animal biodiversity, we recommend that pinyon-juniper woodlands of Zion National Park be managed so that late seral stages do not dominate large tracts.     

Japanese white-eyes (Aves: Zosteropidae) as potential pollinators of summer-flowering Taxillus kaempferi (Loranthaceae)

The pollination of summer-flowering plants by birds has rarely been reported in temperate Asia and Europe. However, we recorded the Japanese white-eye Zosterops japonicus (Passeriformes: Zosteropidae) visiting the flowers of the hemiparasitic plant Taxillus kaempferi (Loranthaceae) during mid-summer (July to August) in a temperate forest in central Japan. Field observations showed that Z. japonicus was an almost exclusive flower visitor of T. kaempferi. Specifically, Z. japonicus inserted their bills frequently into the flower tubes of T. kaempferi. The corollas of T. kaempferi were shorter than Z. japonicus bills, suggesting that Z. japonicus is able to obtain floral nectar from T. kaempferi. Close-up pictures of Z. japonicus visiting flowers showed that the upper bill and facial feathers of Z. japonicus came into contact with the reproductive organs of T. kaempferi, leading to the attachment of pollen to these body parts. Thus, Z. japonicus might act as an important pollinator of the summer-flowering plant T. kaempferi.?     

Distribution of shore bugs and shore flies at Sylvan Springs, Yellowstone National Park

Three species of shore bugs (Hemiptera: Saldidae) and 10 species of brine flies (Diptera: Ephydridae) were collected at Sylvan Springs (Wyoming section of Yellowstone National Park, USA), an area containing both acid and alkaline thermal springs. The fauna consists of both widespread (e.g., shore bugs Saldula comatula Parshley and Saldula explanata [Uhler] and shore flies Atissa litoralis [Cole] and Scatella stagnalis [Fallén]) and Yellowstone Park–endemic species (e.g., Saldula nr. arenicola and the shore fly Ephydra thermophila Cresson). The ratio of adults to nymphs of the numerically dominant shore bug Saldula nr. arenicola is higher along heated margins (11–12:1) than along near-ambient-temperature margins (0.6–2:1) of a thermal channel at Sylvan Springs; this may reflect differences in food availability, osmoregularity, thermal tolerance, predation, or other factors. Shore flies include species typical of acid ( E. thermophila ) and alkaline ( Paracoenia bisetosa [Coquillett] and Paracoenia turbida [Curran]) springs.     

Nest architecture and use of floral oil in the oil-collecting South African solitary bee Rediviva intermixta (Cockerell) (Hymenoptera: Apoidea: Melittidae)

Nest architecture, use of floral oil for brood cell lining and pollen collecting are described for the first time for the genus Rediviva, using the South African endemic oil-collecting solitary bee species Rediviva intermixta. The nest consists of a dead-end vertical tunnel with a single brood cell located at the end of each of several horizontally branching lateral tunnels. Brood cells are lined with a thin layer of waxy material, presumably derived from chemically modified floral oil. Rediviva intermixta is a pollen generalist but relies on a small number of host plant species for oil-collecting. Brood cells are provisioned with pollen from at least six plant families, but with a preference for non-oil-producing Scrophulariaceae. The nesting biology and Dufour’s gland size of the species are discussed and compared with the closely related genera Melitta and Redivivoides (non-oil-collecting) and Macropis (oil-collecting). The differences between Macropis and Rediviva suggest that oil-collecting in the two genera evolved independently.