scholarly journals Selective pollination by fungus gnats potentially functions as an alternative reproductive isolation among five Arisaema species

2020 ◽  
Author(s):  
Tetsuya K Matsumoto ◽  
Muneto Hirobe ◽  
Masahiro Sueyoshi ◽  
Yuko Miyazaki
Keyword(s):  
Reproductive Isolation ◽  
Altitudinal Gradient ◽  
Flowering Phenology ◽  
Altitudinal Distribution ◽  
Interspecific Differences ◽  
Flower Visitation ◽  
Fungus Gnats ◽  
Floral Visitor ◽  
Floral Visitors ◽  
Experimental Plots

Abstract Background and Aims Interspecific difference in pollinators (pollinator isolation) is important for reproductive isolation in flowering plants. Species-specific pollination by fungus gnats has been discovered in several plant taxa, suggesting that they can contribute to reproductive isolation. Nevertheless, their contribution has not been studied in detail, partly because they are too small for field observations during flower visitation. To quantify their flower visitation, we used the genus Arisaema (Araceae) because the pitcher-like spathe of Arisaema can trap all floral visitors. Methods We evaluated floral visitor assemblage in an altitudinal gradient including five Arisaema species. We also examined interspecific differences in altitudinal distribution (geographic isolation) and flowering phenology (phenological isolation). To exclude the effect of interspecific differences in altitudinal distribution on floral visitor assemblage, we established 10 experimental plots including the five Arisaema species on high- and low-altitude areas and collected floral visitors. We also collected floral visitors in three additional sites. Finally, we estimated the strength and contribution of these three reproductive barriers using the unified formula for reproductive isolation. Key Results Each Arisaema species selectively attracted different fungus gnats in the altitudinal gradient, experimental plots, and additional sites. Altitudinal distribution and flowering phenology differed among the five Arisaema species, whereas the strength of geographic and phenological isolations were distinctly weaker than those in pollinator isolation. Nevertheless, the absolute contribution of pollinator isolation to total reproductive isolation was weaker than geographic and phenological isolations, because pollinator isolation functions after the two early-acting barriers in plant life history. Conclusions Our results suggest that selective pollination by fungus gnats potentially contributes to reproductive isolation. Since geographic and phenological isolations can be disrupted by habitat disturbance and interannual climate change, the strong and stable pollinator isolation might compensate for the weakened early-acting barriers as an alternative reproductive isolation among the five Arisaema species.

scholarly journals Floristic Diversity and Distribution Pattern of Plant Communities along Altitudinal Gradient in Sangla Valley, Northwest Himalaya

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Pankaj Sharma ◽  
J. C. Rana ◽  
Usha Devi ◽  
S. S. Randhawa ◽  
Rajesh Kumar
Keyword(s):  
Altitudinal Gradient ◽  
Abiotic Factors ◽  
Floristic Diversity ◽  
Sensitive Species ◽  
Rapid Loss ◽  
Altitudinal Distribution ◽  
Northwest Himalaya ◽  
Qualitative And Quantitative ◽  
The Himalaya ◽  
Insight Into

Himalayas are globally important biodiversity hotspots and are facing rapid loss in floristic diversity and changing pattern of vegetation due to various biotic and abiotic factors. This has necessitated the qualitative and quantitative assessment of vegetation here. The present study was conducted in Sangla Valley of northwest Himalaya aiming to assess the structure of vegetation and its trend in the valley along the altitudinal gradient. In the forest and alpine zones of the valley, 15 communities were recorded. Study revealed 320 species belonging to 199 genera and 75 families. Asteraceae, Rosaceae, Apiaceae, and Ranunculaceae were dominant. Among genera,Artemisiafollowed byPolygonum,Saussurea,Berberis, andThalictrumwere dominant. Tree and shrub’s density ranged from 205 to 600 and from 105 to 1030 individual per hectare, respectively, whereas herbs ranged from 22.08 to 78.95 individual/m2. Nearly 182 species were native to the Himalaya. Maximum altitudinal distribution of few selected climate sensitive species was found to be highest in northeast and north aspects. This study gives an insight into the floristic diversity and community structure of the fragile Sangla Valley which was hitherto not available.

Large mammals generate both top-down effects and extended trophic cascades on floral-visitor assemblages

2019 ◽  
Vol 35 (4) ◽  
pp. 185-198 ◽  
Author(s):  
Allison Louthan ◽  
Emily Valencia ◽  
Dino J. Martins ◽  
Travis Guy ◽  
Jacob Goheen ◽  
...  
Keyword(s):  
Trophic Cascade ◽  
Structural Equation ◽  
Trophic Cascades ◽  
Trophic Levels ◽  
Large Mammals ◽  
Top Down ◽  
Cascading Effects ◽  
Floral Visitor ◽  
Show Evidence ◽  
Floral Visitors

AbstractCascading effects of high trophic levels onto lower trophic levels have been documented in many ecosystems. Some studies also show evidence of extended trophic cascades, in which guilds dependent on lower trophic levels, but uninvolved in the trophic cascade themselves, are affected by the trophic cascade due to their dependence on lower trophic levels. Top-down effects of large mammals on plants could lead to a variety of extended trophic cascades on the many guilds dependent on plants, such as pollinators. In this study, floral-visitor and floral abundances and assemblages were quantified within a series of 1-ha manipulations of large-mammalian herbivore density in an African savanna. Top-down effects of large mammals on the composition of flowers available for floral visitors are first shown, using regressions of herbivore activity on metrics of floral and floral-visitor assemblages. An extended trophic cascade is also shown: the floral assemblage further altered the assemblage of floral visitors, according to a variety of approaches, including a structural equation modelling approach (model with an extended trophic cascade was supported over a model without, AICc weight = 0.984). Our study provides support for extended trophic cascades affecting floral visitors, suggesting that trophic cascades can have impacts throughout entire communities.

BIOSYSTEMATICS OF THE GENUS EUXOA (LEPIDOPTERA: NOCTUIDAE). XVIH. COMPARATIVE BIOLOGY AND EXPERIMENTAL TAXONOMY OF THE SIBLING SPECIES EUXOA RIDMGSIANA (GRT.) AND EUXOA MAIMES (SM.)

1985 ◽  
Vol 117 (4) ◽  
pp. 481-493 ◽  
Author(s):  
J.R. Byers ◽  
D.L. Struble ◽  
J.D. Lafontaine
Keyword(s):  
Life Cycle ◽  
Reproductive Isolation ◽  
Sibling Species ◽  
Mate Recognition ◽  
Recognition System ◽  
Flight Period ◽  
Interspecific Differences ◽  
Mate Recognition System ◽  
The Difference ◽  
Species Specific

AbstractThe species previously recognized as Euxoa ridingsiana (Grt.) is shown to be composed of a sympatric pair of sibling species, Euxoa ridingsiana (Grt.) and Euxoa maimes (Sm.), which in the laboratory will produce viable F1 hybrids but no F2. Results of F1 sib and backcrosses show that the F1 males are fertile and the F1 females are infertile. In mating-bias tests conducted in laboratory cages, 74% of matings were conspecific and 26% interspecific. Differences in the diel periodicities of mating, which are about 2 h out of phase, may account for the mating bias. The duration of development of E. ridingsiana in the laboratory and its seasonal flight period in the field are about 2 weeks in advance of that of E. maimes. However, there is considerable overlap of the flight periods and, with the tendency of females of both species to mate several times, it is unlikely that the difference in seasonal emergence is enough to effect reproductive isolation. It is evident that, under natural conditions, reproductive isolation can be maintained entirely by species-specific sex pheromones. This mechanism of reproductive isolation is, however, apparently ineffective when moths are confined in cages in the laboratory.Biogeographic considerations suggest that the differences in life-cycle timing and mating periodicities might have been adaptations to adjust development and reproduction to prevailing ancestral environments. If the initial differentiation of the 2 species occurred in isolation and included at least an incipient shift in the pheromonal mate-recognition system, it is possible that upon reestablishment of contact between ancestral populations the differences in life-cycle timing and mating periodicities acting in concert could have effected substantial, albeit incomplete, reproductive isolation. Subsequent selection to reinforce assortative mating to preserve coadapted gene complexes could then have resulted in differentiation of discrete pheromonal systems and attainment of species status.

scholarly journals The Genetic Architecture of Reproductive Isolation in Louisiana Irises: Flowering Phenology

Genetics ◽  
2007 ◽  
Vol 175 (4) ◽  
pp. 1803-1812 ◽  
Author(s):  
Noland H. Martin ◽  
Amy C. Bouck ◽  
Michael L. Arnold
Keyword(s):  
Reproductive Isolation ◽  
Genetic Architecture ◽  
Flowering Phenology

scholarly journals Social wasp guild (Hymenoptera: Vespidae) visiting flowers in two of the phytophysiognomic formations: Riparian Forest and campos rupestres

Sociobiology ◽  
2017 ◽  
Vol 64 (2) ◽  
pp. 217
Author(s):  
Mateus Aparecido Clemente ◽  
Karine Munck Vieira ◽  
Núbia Ribeiro Campos ◽  
Kleber Del-Claro ◽  
Fábio Prezoto
Keyword(s):  
Plant Species ◽  
Riparian Forest ◽  
Social Wasp ◽  
Sampling Effort ◽  
Campos Rupestres ◽  
Wasp Species ◽  
Floral Visitor ◽  
Floral Visitors ◽  
Flower Visiting ◽  
One Year

Social wasps are part of the floral visitor guild. In this study we investigated the distribution of flower-visiting wasp species in two phytophysiognomies in the State Park of Ibitipoca, Minas Gerais, Brazil. We inspected flowering plants with visiting wasps along a 1 km transect in riparian forest and another 1 km transect in campos rupestres over the course of one year, for a total sampling effort of 240 hours. We found a total of 103 individuals with 15 species distributed among 7 genera, the most common belonging to the Erythroxylaceae (n = 10) and Asteraceae (n = 10) families. Asteraceae had the highest abundance (N = 55). The diversity and evenness of these insects was higher in riparian forest (H '= 0.78 and J' = 0.75) than in campos rupestres (H '= 0.30, J' = 0.39). All species visited flowers of 19 plant species in riparian forest, and eight wasp species visited 11 plant species in campos rupestres. These Polistinae acted as regular floral visitors, thus, conservation programs in these areas may be relevant for the maintenance of social wasp diversity.

scholarly journals Drastic shift in flowering phenology, an instant reproductive isolation mechanism, explains the population structure of Imperata cylindrica in Japan

2020 ◽  
Author(s):  
Yasuyuki Nomura ◽  
Yoshiko Shimono ◽  
Nobuyuki Mizuno ◽  
Ikuya Miyoshi ◽  
Satoshi Iwakami ◽  
...  
Keyword(s):  
Reproductive Isolation ◽  
Low Temperatures ◽  
Flowering Phenology ◽  
Germination Percentage ◽  
Imperata Cylindrica ◽  
Wild Plants ◽  
New Combination ◽  
Hybrid Population ◽  
The Novel ◽  
Novel Traits

AbstractReproductive isolation plays an important role in population differentiation and speciation, thus enhancing biodiversity in wild plants. Hybridisation sometimes involves rapid reproductive isolation between parents and their hybrids through the novel traits of hybrids derived from a new combination of genomes. Here, we report how a hybrids’ new phenotype contributes to rapid reproductive isolation between two ecotypes of Imperata cylindrica. The two ecotypes differ in their flowering phenology and habitats. An analysis with genetic markers revealed that hybrid populations consisted of only F1 individuals. Both parental ecotypes flowered in spring, but F1s flowered in fall. This drastic shift in flowering phenology prevented backcrossing parental ecotypes to F1. F1s flowered in fall and dispersed seeds in winter. The germination percentage of seeds set on F1 was extremely low in their habitats, and seedlings did not survive due to the low temperatures in winter, resulting in the absence of a F2 generation. In conclusion, flowering phenology mismatch promotes reproductive isolation between parents and F1, resulting in a hybrid population consisting of only F1s.

High-mountain altitudinal gradient influences thermal ecology of the Mesquite Lizard (Sceloporus grammicus)

2019 ◽  
Vol 97 (8) ◽  
pp. 659-668 ◽  
Author(s):  
A.H. Díaz de la Vega-Pérez ◽  
R. Barrios-Montiel ◽  
V.H. Jiménez-Arcos ◽  
A. Bautista ◽  
E. Bastiaans
Keyword(s):  
Altitudinal Gradient ◽  
The Body ◽  
High Mountain ◽  
Thermal Ecology ◽  
Behavioral Strategies ◽  
Body Temperatures ◽  
Altitudinal Distribution ◽  
Thermal Requirements ◽  
Sceloporus Grammicus

The thermal requirements of ectotherms may vary among species due to adaptation to different thermal environments. Nevertheless, some of these requirements are evolutionarily conserved, leading organisms to compensate behaviorally for harsh environmental conditions. High-mountain systems provide temperature gradients that allow for studies of evolutionary and plastic variation in thermal ecology under natural conditions. We evaluated the thermoregulation strategies of Sceloporus grammicus Wiegmann, 1828 at three points (2600, 3100, and 4150 m above sea level) along an altitudinal gradient. We found that the thermal quality of the site and the body temperatures of lizards are influenced by altitude and decrease with increasing elevation. However, lizards from the three different elevations have similar thermal requirements. High-altitude lizards have lower thermal accuracy and efficiency indices compared with those from the lower sites, owing to the low thermal quality of their environment. Nevertheless, they are efficient in thermoregulation, increasing their body temperature above the ambient temperature. We found that pregnant females from all three elevations had similar preferred body temperatures. Compared with nonpregnant females and males, they exhibited lower preferred temperatures and more accurate thermoregulation. The wide altitudinal distribution of S. grammicus is thus not caused by variable thermal requirements. Instead, the wide repertoire of physiological and behavioral strategies of these lizards allows this species to successfully inhabit contrasting environments.

A cytotaxonomic study of Australian Cardamine

1968 ◽  
Vol 16 (3) ◽  
pp. 515 ◽  
Author(s):  
N Thurling
Keyword(s):  
Reproductive Isolation ◽  
Native Species ◽  
Cytogenetic Study ◽  
Morphological Differentiation ◽  
Distinct Species ◽  
The Other ◽  
F1 Hybrids ◽  
Altitudinal Distribution ◽  
South Wales ◽  
Morphological Differences

A cytogenetic study of Cardamine, based on material collected in southern New South Wales and the Australian Capital Territory, indicated the presence of at least six distinct species in this area. Two species, the 16-chromosome C. hirsuta and the 32- chromosome C. flexuosa, were introduced with white settlement. The other four species are native to the area, occupying a variety of habitats between sea-level and 7200 ft. One species, with a somatic chromosome number of 64, is confined to altitudes below 4000 ft, whereas the other three species (2n = 48) are found only above 4000 ft. Of the 48-chromosome species, one comprises a single population found at Mt. Franklin and the remaining two are confined to particular altitudinal ranges, one between 4000 and 5400 ft and the other between 5200 and 7200 ft. All four native species are completely isolated from one another by the inviability of the F1 hybrids. Within species, however, all populations were fully interfertile and there was no evidence of any other form of reproductive isolation. Despite the magnitude of reproductive isolation there were no distinct morphological differences between the native species except in the case of the 48-chromosome form from Mt. Franklin, which had entire rather than pinnate leaves. The other three species were in fact more comparable to ecotypes in respect of their altitudinal distribution and the degree of morphological differentiation. Speciation mechanisms involved in the evolution of the native species of Cardamine are discussed.

scholarly journals Temporal Changes and Altitudinal Distribution of Aerobic Anoxygenic Phototrophs in Mountain Lakes

2013 ◽  
Vol 79 (20) ◽  
pp. 6439-6446 ◽  
Author(s):  
Zuzana Čuperová ◽  
Evelyn Holzer ◽  
Ivette Salka ◽  
Ruben Sommaruga ◽  
Michal Koblížek
Keyword(s):  
Altitudinal Gradient ◽  
Alpine Lakes ◽  
Temporal Changes ◽  
Mountain Lakes ◽  
Epifluorescence Microscopy ◽  
Organic Substrates ◽  
Altitudinal Distribution ◽  
Anoxygenic Phototrophs ◽  
Aerobic Anoxygenic Phototrophs ◽  
Low Altitude

ABSTRACTAerobic anoxygenic phototrophs (AAPs) are bacteriochlorophylla-containing microorganisms that use organic substrates for growth but can supplement their energy requirements with light. They have been reported from various marine and limnic environments; however, their ecology remains largely unknown. Here infrared epifluorescence microscopy was used to monitor temporal changes in AAPs in the alpine lake Gossenköllesee, located in the Tyrolean Alps, Austria. AAP abundance was low (103cells ml−1) until mid-July and reached a maximum of ∼1.3 × 105cells ml−1(29% of all prokaryotes) in mid-September. We compared the studied lake with other mountain lakes located across an altitudinal gradient (913 to 2,799 m above sea level). The concentration of dissolved organic carbon and water transparency seem to be the main factors influencing AAP abundance during the seasonal cycle as well as across the altitudinal gradient. While the AAP populations inhabiting the alpine lakes were composed of intensely pigmented large rods (5 to 12 μm), the lakes below the tree line were inhabited by a variety of smaller morphotypes. Analysis ofpufMdiversity revealed that AAPs in Gossenköllesee were almost exclusivelySphingomonadalesspecies, which indicates that AAP communities inhabiting alpine lakes are relatively homogeneous compared to those in low-altitude lakes.

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