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.     

Pollination experiments in the Mimulus cardinalis--M. lewisii complex

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.     

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.     

A new variety of Centaurium namophilum (Gentianaceae) from the Great Basin

An expression of Centaurium namophilum (Gentianaceae), long confused with C. exaltatum in the Great Basin of the western United States, is described and designated as var. nevadense. It may be separated from the Death Valley region endemic, var. namophilum, by its broader leaves, its diffuse corymbose cyme, the ultimate peduncles that are longer than the flowers, its medium to deep rose pink corolla, and its stamens that equal or exceed the style and are only slightly exserted from the corolla-tube. The var. nevadense occurs from eastern California to western Utah, and from southeastern Oregon and adjacent Idaho south to the northern Mojave Desert of southeastern California. Centaurium exaltatum may be distinguished from the new variety by its broader, more elliptical leaves, dichotomous peduncles, paler pink or bluish and generally four-merous flowers, shorter and more blunt corolla lobes, and a thicker, more included style and stigma.     

Adult butterfly feeding–nectar flower associations: constraints of taxonomic affiliation,butterfly, and nectar flower morphology

Butterfly–flower morphological interrelationships were investigated for 108 butterfly species and 20 plants at Nagpur, India. Distinct clusters of higher taxa (families) are disclosed for butterfly morphology and significant morphological and taxonomic associations occur in nectar exploitation. Flower corolla depth generally restricts exploitation by butterflies in relation to proboscis length and butterflies with high wing load indices bias their feeding to plants with massed flowers. However, important exceptions emerge; also, a substantial number of butterflies feed on plants with massed flowers though their proboscises are of marginal length for corolla depths. These butterfly species are significantly smaller, lighter, with lower wing loading and shorter proboscis indices than species which easily access the same flowering plant species. It is suggested that small size and short proboscises could give them a competitive advantage (increased rate of nectar uptake) for exploiting nectar in such situations. The significance of the findings for conservation is discussed.     

Mimulus evanescens (Scrophulariaceae): a new annual species from the northern Great Basin

Recent taxonomic studies in Mimulus support the recognition of Mimulus evanescens , a new autogamous species morphologically allied with M. breviflorus and M. latidens . Initially known only from herbarium specimens, the most recent from 1958, M. evanescens was relocated in the field in 1990 in northern Lassen Co., CA. A second population was found in southern Lake Co., OR, in 1993. Mimulus evanescens is apparently confined to the Great Basin and its periphery, where it has been recorded from 10 localities across Idaho, Oregon, and California. Based on collection information and visits to the two extant populations, the new species appears to be restricted to vernally moist sites and fluctuating banks of intermittent streams or pools. Long-term utilization of such sites by livestock may have contributed to the present-day rarity of M. evanescens . The species should be added to federal and state lists of candidate endangered species pending the results of future field studies and surveys.     

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.     

Variance and replenishment of nectar in wild and greenhouse populations of Mimulus

We compared nectar production in wild populations and greenhouse-grown populations of the monkey flower species of section Erythranthe of the genus Mimulus . Nectar was sampled from over 1000 flowers. For each flower the volume of nectar was measured with a calibrated micropipette and the percentage of sugar with a hand refractometer. Percentage of sugar varied little from flower to flower in both field and greenhouse studies, but volume varied markedly from flower to flower in field studies and even more in greenhouse studies. This high variance in nectar volumes appears to be intrinsic. The amount of nectar in greenhouse populations tended to increase with time in the absence of pollinators. The amount of nectar in field populations tended to remain the same to pollinator withdrawals. The latter conclusion was corroborated by sampling nectar at 2-h intervals all day and comparing the total volume produced by a flower to the volume of nectar produced in control flowers sampled only at the end of the day.     

New species of Mentzelia (Loasaceae) from Grand County, Utah

A new species, Mentzelia (Section Bartonia ) shultziorum , of the Loasaceae (Mentzelioideae) is described. A close relationship with M. multicaulis (Osterh.) Darl. and M. argillosa Darl. is suggested based on the morphology of the flowers, leaves, and seeds.     

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.     

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.       

A putative hybrid swarm within O?nopsis foliosa (Asteraceae: Astereae)

O?nopsis foliosa var. foliosa and var. monocephala are endemic to short-grass steppe of southeastern Colorado and until recently were considered geographically disjunct. The only known qualitative feature separating these 2 varieties is floral head type; var. foliosa has radiate heads, whereas var. monocephala heads are discoid. Sympatry between these varieties is restricted to a small area in which a range of parental types and intermediate head morphologies is observed. We used distribution mapping, morphometric analyses, chromosome cytology, and pollen stainability to characterize the sympatric zone. Morphometrics confirms that the only discrete difference between var. foliosa and var. monocephala is radiate versus discoid heads, respectively. The outer florets of putative hybrid individuals ranged from conspicuously elongated yet radially symmetric disc-floret corollas, to elongated radially asymmetric bilabiate- or deeply cleft corollas, to stunted ray florets with appendages remnant of corolla lobes. Chromosome cytology of pollen mother cells from both putative parental varieties and a series of intermediate morphological types collected at the sympatric zone reveal evidence of translocation heterozygosity. Pollen stainability shows no significant differences in viability between the parental varieties and putative hybrids. The restricted distribution of putative hybrids to a narrow zone of sympatry between the parental types and the presence of meiotic chromosome-pairing anomalies in these intermediate plants are consistent with a hybrid origin. The high stainability of putative-hybrid pollen adds to a growing body of evidence that hybrids are not universally unfit.     

The hemipenis of lacertid lizards (Reptilia: Lacertidae): structure,variation and systematic implications

The basic anatomy of the lacertid hemipenis (intromittent organ) and methods for its investigation are described. In many members of the Lacertidae, the hemipenis has a structure quite unlike that of other squamate reptiles: the distal lobes of the retracted organ are complexly folded and there is a well-defined supporting structure of dense connective tissue, the armature. This incorporates blood sinuses and has an intramuscular portion embedded in the m. retractor penis magnus and two club-shaped bodies, the clavulae, that support the lobes in the erect organ. Unarmatured hemipenes occur in some lacertids and, like those of other squamates, possess sac-like lobes in the retracted state, but they are singular in having the lobes invested by the m. retractor penis magnus. It is argued that many of these apparently primitive hemipenes are in fact secondary derivatives of the armatured type.

There is considerable inter-specific variation in hemipenial structure which is described systematically. In some cases this involves differences in size, asymmetry and simplification, which may arise as physical isolating mechanisms and is useful in distinguishing otherwise very similar species, particularly in the genus Mesalina (p. 1253). Other shared derived hemipenial features provide useful information about relationships between species and higher taxa and a summary of the hypotheses that they support is given (p. 1254).     

Scale‐worms (Polychaeta,Polynoidae) associated with chaetopterid worms (Polychaeta,Chaetopteridae), with description of a new genus and species

Three species of scale‐worms inhabiting chaetopterid tubes have been found during routine studies of benthic communities. Anotochaetonoe michelbhaudi gen. and sp. nov. occurred in the East Atlantic off Congo in association with Spiochaetopterus sp. and Phyllochaetopterus sp. It has a relatively short body (fewer than 50 segments); elytra in posterior part of the body arranged on chaetigers 23, 26, 29, 32, 34, 37, 40, 43, 46, present to posterior end; achaetous notopodia; neuropodia long, with longer subtriangular prechaetal lobes and shorter postchaetal lobes rounded distally; upper neurochaetae unidentate and lower bidentate; globular ciliated papillae present between ventral cirri and ventral basis of neuropodia. Lepidasthenia brunnea occurred in the Mediterranean Sea off the French coast both free‐living and in association with Phyllochaetopterus sp. Ophthalmonoe pettiboneae was found in Vietnam (South China Sea) in association with Chaetopterus sp. This is the second finding of the species. The characteristics of the associations between chaetopterid genera and symbiotic polychaetes are discussed.     

Histology of the brain of the larva of Chilocorus nigritus Fabr. (Coleoptera: Coccinellidae), with special reference to the fibre tracts

Summary

The finer anatomy of the brain of the larva has been studied. The protocerebrum consists of pons cerebralis, corpora ventralia, mushroom bodies and three optic lobes. The central complex is represented by the pons cerebralis and central body, and the latter is joined with the copora ventralia by fine fibre tracts. The anterior and posterior optic commissures join the inner optic lobes of the two sides. The antennary nerves arise from the deutocerebral lobes. The antennocerebral tract joins the deutocerebral and protocerebral lobes with each other. Tritocerebral lobes are small and a commissure joins the two tritocerebral lobes.     

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 .     

Breeding biology and flower visitors of the rare White River penstemon, Penstemon scariosus var. albifluvis (Scrophulariaceae)

We studied the breeding system and flower visitors of White River penstemon, a rare endemic from the Uintah Basin of eastern Utah and western Colorado. Bagging treatments and hand-pollination treatments showed that Penstemon scariosus var. albifluvis has a mixed mating system: while some seeds and fruits are produced through selfpollination (both autogamy and geitonogamy), significantly more are produced when flowers are cross-pollinated. The primary flower visitors, and likely pollinators, were several species of native twig- and ground-nesting bees in the families Apidae, Halictidae, and Megachilidae. We found no differences in fruit or seed production between open-pollinated controls and hand-outcrossed flowers, suggesting that pollinator visits were sufficient to maximize female reproductive success. Management plans to conserve White River penstemon must recognize that full reproductive success of this rare plant taxon relies on a suite of pollinating bees, and that the species richness and abundances of bee visitors should be maintained.     

A mixed pollination system in Penstemon pseudospectabilis M. E. Jones (Scrophulariaceae)

A population of Penstemon pseudospectabilis M. E. Jones (Scrophulariaceae) on Cave Creek in Cochise County, Arizona, was used in an experimental test of reproductive fitness with three caging treatments: all flying pollinators excluded, hummingbirds excluded, and no exclusion. Twenty plants were chosen and three shoots on each used in the experiment. The flowers were 25.6 (s.d. = 1.5) mm long, the end diameter was 8.5 (s.d. = 1.0) mm, the tube opening was 6.5 (s.d. = 1.0) mm, and the greatest diameter, 75% distal from the receptacle, was 10.1 (s.d. = 0.8) mm (N= 59). Floral nectar contained 11.7% (s.d. = 2.9%) fructose, 13.8% (s.d. = 2.7%) glucose, and 74.5% (s.d. = 5.4%) sucrose (N = 74). There was some evidence, significant only for fructose, that nectar-sugar composition varies between morning and evening. Larger floral dimensions were correlated with lower sucrose and higher hexoses. Casual observation showed Xylocopa sp., small bees, flies, and hummingbirds to be visitors. There was no sign of nectar robbing. Five percent of flowers set seed with all pollen vectors excluded, 44% with hummingbirds excluded, and 63%with no exclusion. Seed set per fruit was 2 with all excluded, 23 with hummingbirds excluded, and 46 with no exclusion. Mean seed set on pollinated flowers was 60, with a range of 2 to 192. Multiple linear regression showed the fraction of fruit setting seed when hummingbirds were excluded to be related to larger flower diameters and shorter flowers. With no pollinator exclusion, fruits setting seed were related to larger diameters and nectar fructose. For seeds per fruit, multiple regression gave similar, but less clear, results. We conclude that P. pseudospectabilis is pollinated by both bees and hummingbirds, with other pollinators not to be excluded as possible contributors. We found no hard evidence of selective forces currently at work.     

A new species of Frasera (Gentianaceae) from Uinta Basin, Utah

Frasera ackermanae, sp. nov. is described based on specimens collected from the Brush Creek drainage, Uinta Basin in Uintah County, Utah. The short stem, compact inflorescence, and longer calyx lobes separate this species from the similar Frasera pahutensis Reveal.