scholarly journals Nectar-living yeasts of a tropical host plant community: diversity and effects on community-wide floral nectar traits

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3517 ◽  
Author(s):  
Azucena Canto ◽  
Carlos M. Herrera ◽  
Rosalina Rodriguez

We characterize the diversity of nectar-living yeasts of a tropical host plant community at different hierarchical sampling levels, measure the associations between yeasts and nectariferous plants, and measure the effect of yeasts on nectar traits. Using a series of hierarchically nested sampling units, we extracted nectar from an assemblage of host plants that were representative of the diversity of life forms, flower shapes, and pollinator types in the tropical area of Yucatan, Mexico. Yeasts were isolated from single nectar samples; their DNA was identified, the yeast cell density was estimated, and the sugar composition and concentration of nectar were quantified using HPLC. In contrast to previous studies from temperate regions, the diversity of nectar-living yeasts in the plant community was characterized by a relatively high number of equally common species with low dominance. Analyses predict highly diverse nectar yeast communities in a relatively narrow range of tropical vegetation, suggesting that the diversity of yeasts will increase as the number of sampling units increases at the level of the species, genera, and botanical families of the hosts. Significant associations between specific yeast species and host plants were also detected; the interaction between yeasts and host plants impacted the effect of yeast cell density on nectar sugars. This study provides an overall picture of the diversity of nectar-living yeasts in tropical host plants and suggests that the key factor that affects the community-wide patterns of nectar traits is not nectar chemistry, but rather the type of yeasts interacting with host plants.

2014 ◽  
Vol 6 (3) ◽  
pp. 316-320
Author(s):  
Fatai Adekanye OLOYEDE ◽  
Anthony I. ODIWE ◽  
Ayodeji S. OLUJIYAN

Composition and distribution of vascular epiphytes were studied in three different areas at Obafemi Awolowo University estate, Nigeria. Each plot, in the selected area, was used for identification of host and epiphytes. Trees were carefully examined. Presence, positions on the host plants and life-forms of all the epiphytes were recorded. Diameter at breast height of the hosts, bark characteristics and height were determined. The climatic data of the areas were measured to determine the relationship between them and epiphytes distributions. Result showed 41 epiphytes belonging to 14 genera and 11 families were identified. Open area had the highest number of epiphytes (22) followed by forest patches (14) then secondary forest (five). The epiphytes were not host specific except epiphytic ferns and Ficus vogelii. Diameter at breast height has effect on the epiphytes distribution and composition. The distribution of epiphytes and environmental factors were lowest in the secondary forest. Moraceae was the most dominant host family (44.8%) while Nephrolepis undulata and Nephrolepis biserrata were the most common species of epiphytes. Most epiphytes preferred sub-canopy level, few occurred in the canopy level but none at emergent level. Climatic factors, diameter at breast height and bark characteristics of the host plants are useful in determining compositions and distributions of these epiphytes.


Author(s):  
Marcin W. Zielonka ◽  
Tom W. Pope ◽  
Simon R. Leather

Abstract The carnation tortrix moth, Cacoecimorpha pronubana (Hübner, [1799]) (Lepidoptera: Tortricidae), is one of the most economically important insect species affecting the horticultural industry in the UK. The larvae consume foliage, flowers or fruits, and/or rolls leaves together with silken threads, negatively affecting the growth and/or aesthetics of the crop. In order to understand the polyphagous behaviour of this species within an ornamental crop habitat, we hypothesized that different host plant species affect its life history traits differently. This study investigated the effects of the host plant species on larval and pupal durations and sizes, and fecundity (the number of eggs and the number and size of egg clutches). At 20°C, 60% RH and a 16L:8D photoperiod larvae developed 10, 14, 20 and 36 days faster when reared on Christmas berry, Photinia (Rosaceae), than on cherry laurel, Prunus laurocerasus (Rosaceae), New Zealand broadleaf, Griselinia littoralis (Griseliniaceae), Mexican orange, Choisya ternata (Rutaceae), and firethorn, Pyracantha angustifolia (Rosaceae), respectively. Female pupae were 23.8 mg heavier than male pupae, and pupal weight was significantly correlated with the duration of larval development. The lowest and the highest mean numbers of eggs were produced by females reared on Pyracantha (41) and Photinia (202), respectively. Clutch size differed significantly among moths reared on different host plants, although the total number of eggs did not differ. This study showed that different ornamental host plants affect the development of C. pronubana differently. Improved understanding of the influence of host plant on the moth's life history parameters measured here will help in determining the economic impact that this species may have within the ornamental plant production environment, and may be used in developing more accurate crop protection methodologies within integrated pest management of this insect.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Belén Cotes ◽  
Gunda Thöming ◽  
Carol V. Amaya-Gómez ◽  
Ondřej Novák ◽  
Christian Nansen

AbstractRoot-associated entomopathogenic fungi (R-AEF) indirectly influence herbivorous insect performance. However, host plant-R-AEF interactions and R-AEF as biological control agents have been studied independently and without much attention to the potential synergy between these functional traits. In this study, we evaluated behavioral responses of cabbage root flies [Delia radicum L. (Diptera: Anthomyiidae)] to a host plant (white cabbage cabbage Brassica oleracea var. capitata f. alba cv. Castello L.) with and without the R-AEF Metarhizium brunneum (Petch). We performed experiments on leaf reflectance, phytohormonal composition and host plant location behavior (behavioral processes that contribute to locating and selecting an adequate host plant in the environment). Compared to control host plants, R-AEF inoculation caused, on one hand, a decrease in reflectance of host plant leaves in the near-infrared portion of the radiometric spectrum and, on the other, an increase in the production of jasmonic, (+)-7-iso-jasmonoyl-l-isoleucine and salicylic acid in certain parts of the host plant. Under both greenhouse and field settings, landing and oviposition by cabbage root fly females were positively affected by R-AEF inoculation of host plants. The fungal-induced change in leaf reflectance may have altered visual cues used by the cabbage root flies in their host plant selection. This is the first study providing evidence for the hypothesis that R-AEF manipulate the suitability of their host plant to attract herbivorous insects.


Nematology ◽  
2004 ◽  
Vol 6 (3) ◽  
pp. 375-387 ◽  
Author(s):  
N. Aileen Ryan ◽  
Peter Jones

AbstractSeventy bacteria, isolated from the rhizosphere of the potato cyst nematode (PCN) host plant, potato, were cultured in the presence and absence of potato root leachate (PRL) and the resultant culture filtrates were analysed for their ability to affect the hatch in vitro of the two PCN species. Of the isolates tested, nine had a significant effect on PCN hatch. Six affected Globodera pallida hatch and three affected G. rostochiensis hatch. Five of the isolates significantly increased hatch only when cultured in the presence of PRL. Three of the isolates decreased PCN hatch significantly in PRL. Only one isolate increased hatch significantly in the absence of PRL. No isolate affected the hatch of both species. Six of the nine isolates that significantly affected PCN hatch had been pre-selected by culturing on PRL. Bacterial isolates from PCN non-hosts (14 from wheat, 17 from sugar beet) were also tested for hatching activity. The principal effect of the hatch-active isolates from the PCN non-host plants was to increase PCN hatch in the presence of PRL. In contrast to the host bacteria results, the isolates from non-host plants affected only G. rostochiensis hatch (three wheat isolates and four sugar beet isolates significantly increased G. rostochiensis hatch); no such isolate affected G. pallida hatch significantly in the presence of PRL. Ten isolates (32%) from non-host plants had the ability to increase significantly the hatch of PCN in the absence of PRL (eight of these affected G. rostochiensis hatch and four affected G. pallida hatch), compared to only one bacterial isolate (1%) from a host plant. The majority of the isolates from non-hosts produced PCN species-specific effects, as with the bacteria isolated from potatoes, although two wheat isolates increased the hatch of both species significantly in the absence of PRL. Of 20 hatch-active bacterial isolates (from all three plants) identified, 70% were Bacillus spp. Other genera identified were Arthrobacter , Acinetobacter and Staphylococcus .


2020 ◽  
Vol 117 (9) ◽  
pp. 4464-4470 ◽  
Author(s):  
Susan Harrison ◽  
Marko J. Spasojevic ◽  
Daijiang Li

Climate strongly shapes plant diversity over large spatial scales, with relatively warm and wet (benign, productive) regions supporting greater numbers of species. Unresolved aspects of this relationship include what causes it, whether it permeates to community diversity at smaller spatial scales, whether it is accompanied by patterns in functional and phylogenetic diversity as some hypotheses predict, and whether it is paralleled by climate-driven changes in diversity over time. Here, studies of Californian plants are reviewed and new analyses are conducted to synthesize climate–diversity relationships in space and time. Across spatial scales and organizational levels, plant diversity is maximized in more productive (wetter) climates, and these consistent spatial relationships are mirrored in losses of taxonomic, functional, and phylogenetic diversity over time during a recent climatic drying trend. These results support the tolerance and climatic niche conservatism hypotheses for climate–diversity relationships, and suggest there is some predictability to future changes in diversity in water-limited climates.


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