scholarly journals Pollination ecology of the Australian cycad Lepidozamia peroffskyana (Zamiaceae)

2004 ◽  
Vol 52 (3) ◽  
pp. 333 ◽  
Author(s):  
John A. Hall ◽  
Gimme H. Walter ◽  
Dana M. Bergstrom ◽  
Peter Machin
Keyword(s):  
Spatial Distribution ◽  
Life Cycle ◽  
Seed Set ◽  
Receptive Female ◽  
Pollen Load ◽  
Global Diversity ◽  
Large Numbers ◽  
Insect Pollinators ◽  
Male Cones ◽  
Lines Of Evidence

Experiments carried out to investigate the reproductive ecology of the Australian cycad Lepidozamia peroffskyana (Regal, Bull. Soc. Imp. Nat. Mosc. 1857, 1: 184) revealed that this species is pollinated exclusively by host-specific Tranes weevils (Pascoe 1875). The weevils carry out their life cycle within the tissues of the male cones but also visit the female cones in large numbers. Female cones from which insects (but not wind) was excluded had a pollination rate that was essentially zero. In contrast, female cones from which wind (but not insects) were excluded had a pollination rate comparable with naturally pollinated cones. Assessment of Tranes weevil pollen load indicated that they are effective pollen-carriers. No other potential insect pollinators were observed on cones of L. peroffskyana. Sampling of airborne loads of cycad pollen indicated that wind-dispersed grains were not consistently recorded beyond a 2-m radius surrounding pollen-shedding male cones. The airborne load of cycad pollen in the vicinity of pollination-receptive female cones was minimal, and the spatial distribution of the coning population indicated that receptive female cones did not usually occur close enough to pollen-shedding male cones for airborne transfer of pollen to explain observed natural rates of seed set. These multiple lines of evidence suggest that wind–once considered the only pollination vector for cycads and other gymnosperms–plays only a minimal role in the pollination of L. peroffskyana, if any at all. The global diversity of insects associated with cycads suggests that some lineages of pollinating beetles may have been associated with cycad cones since Mesozoic times.

Modeling spatial distribution of the unionid mussels and the core-satellite hypothesis

1998 ◽  
Vol 38 (7) ◽  
pp. 73-79 ◽  
Author(s):  
Hooi-Ling Lee ◽  
Donald DeAngelis ◽  
Hock-Lye Koh
Keyword(s):  
Spatial Distribution ◽  
Life Cycle ◽  
Success Rate ◽  
Distribution Patterns ◽  
Fish Host ◽  
Limited Movement ◽  
Unionid Mussels ◽  
Species Characteristics ◽  
Major Factors ◽  
Fish Hosts

This paper discusses the spatial distribution patterns of the various species of the Unionid mussels as functions of their respective life-cycle characteristics. Computer simulations identify two life-cycle characteristics as major factors governing the abundance of a species, namely the movement range of their fish hosts and the success rate of the parasitic larval glochidia in finding fish hosts. Core mussels species have fish hosts with large movement range to disperse the parasitic larval glochidia to achieve high levels of abundance. Species associated with fish host of limited movement range require high success rate of finding fish host to achieve at least an intermediate level of abundance. Species with low success rate of finding fish hosts coupled with fish hosts having limited movement range exhibit satellite species characteristics, namely rare in numbers and sparse in distributions.

scholarly journals Distribution of Bacillus thuringiensis subsp. israelensis in Soil of a Swiss Wetland Reserve after 22 Years of Mosquito Control

2011 ◽  
Vol 77 (11) ◽  
pp. 3663-3668 ◽  
Author(s):  
Valeria Guidi ◽  
Nicola Patocchi ◽  
Peter Lüthy ◽  
Mauro Tonolla
Keyword(s):  
Spatial Distribution ◽  
Bacillus Thuringiensis ◽  
Confidence Interval ◽  
Quantitative Pcr ◽  
Mosquito Control ◽  
Soil Samples ◽  
Sampling Point ◽  
Content Type ◽  
Large Numbers ◽  
Continuous Accumulation

ABSTRACTRecurrent treatments withBacillus thuringiensissubsp.israelensisare required to control the floodwater mosquitoAedes vexansthat breeds in large numbers in the wetlands of the Bolle di Magadino Reserve in Canton Ticino, Switzerland. Interventions have been carried out since 1988. In the present study, the spatial distribution of restingB. thuringiensissubsp.israelensisspores in the soil was measured. TheB. thuringiensissubsp.israelensisconcentration was determined in soil samples collected along six transects covering different elevations within the periodically flooded zones. A total of 258 samples were processed and analyzed by quantitative PCR that targeted an identical fragment of 159 bp for theB. thuringiensissubsp.israelensis cry4Aaandcry4Bagenes.B. thuringiensissubsp.israelensisspores were found to persist in soils of the wetland reserve at concentrations of up to 6.8 log per gram of soil. Continuous accumulation due to regular treatments could be excluded, as the decrease in spores amounted to 95.8% (95% confidence interval, 93.9 to 97.7%). The distribution of spores was correlated to the number ofB. thuringiensissubsp.israelensistreatments, the elevation of the sampling point, and the duration of the flooding periods. The number ofB. thuringiensissubsp.israelensistreatments was the major factor influencing the distribution of spores in the different topographic zones (P< 0.0001). These findings indicated thatB. thuringiensissubsp.israelensisspores are rather immobile after their introduction into the environment.

Studies on Theocolax formiciformis Westw. (Hym., Pteromalidae), a parasite of Anobium punctatum (Deg.) (Col., Anobiidae)

1964 ◽  
Vol 54 (4) ◽  
pp. 797-803 ◽  
Author(s):  
Jean M. Taylor
Keyword(s):  
Biological Control ◽  
Life Cycle ◽  
Relative Humidity ◽  
Wood Surface ◽  
Biological Control Agent ◽  
Glass Plate ◽  
Control Agent ◽  
Large Numbers ◽  
Cent Relative Humidity ◽  
Anobium Punctatum

A description is given of the life-cycle in Britain of Theocolax formiciformis Westw. (Pteromalidae), a parasite of Anobium punctatum (Deg.) (Anobiidae). Adults emerge from infested wood in large numbers from April to June. Eggs are laid through the wood surface and use was made of this habit as a means of rearing this parasite under observation in the laboratory. Anobium larvae were placed individually in channels gouged in the surface of 3-inch squares of plywood. They were covered with tracing paper and the parasites were caged on this by means of a glass ring covered with a glass plate. Development from egg to adult at 22 and 25°C., and 75 per cent, relative humidity, averaged about five and six weeks, respectively, compared with 12 weeks outdoors in summer. The number of progeny per female was highest (approximately five) at 22°C., at which the ratio of males to females was 1:3. Only about one per cent, of the adults reared were winged. The use of Theocolax as a biological-control agent is not considered practical.

Feltia submontana (Noctuidae, Noctuinae): Redescription, Taxonomy, Life Cycle, and Spatial Distribution of a Neglected South American Potential Pest Species

2018 ◽  
Vol 48 (1) ◽  
pp. 98-110 ◽  
Author(s):  
F M S Dias ◽  
A Specht ◽  
V F Roque-Specht ◽  
G San Blas ◽  
M M Casagrande ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Life Cycle ◽  
South American ◽  
Pest Species ◽  
Potential Pest

Mission-Level Optimization: Complex Systems Design for Highly Stochastic Life Cycle Use Case Scenarios

2020 ◽  
Author(s):  
Brian Chell ◽  
Steven Hoffenson ◽  
Benjamin Kruse ◽  
Mark R. Blackburn
Keyword(s):  
Life Cycle ◽  
Systems Design ◽  
System Optimization ◽  
Optimization Under Uncertainty ◽  
Modeling And Analysis ◽  
Mission Success ◽  
Large Numbers ◽  
Key Stakeholders ◽  
System Life ◽  
Engineering Modeling

Abstract Mission engineering is a growing field with many practical opportunities and challenges. The goal of mission engineering is to increase system effectiveness, reduce life cycle costs, and aid in communicating system capabilities to key stakeholders. Optimizing system designs for their mission context is important to achieving these goals. However, system optimization is generally done using multiple key performance indicators (KPIs), which are not always directly representative of, nor easily translatable to, mission success. This paper introduces, motivates, and proposes a new approach for performing mission-level optimization (MLO), where the objective is to design systems that maximize the probability of mission success over the system life cycle. This builds on previous literature related to mission engineering, modeling, and analysis, as well as optimization under uncertainty. MLO problems are unique in their high levels of design, operational, and environmental uncertainty, as well as the single binary objective representing mission success or failure. By optimizing for mission success, designers can account for large numbers of KPIs and external factors when determining the best possible system design.

scholarly journals Pollen adaptation to ant pollination: a case study from the Proteaceae

2020 ◽  
Vol 126 (3) ◽  
pp. 377-386 ◽  
Author(s):  
Nicola Delnevo ◽  
Eddie J van Etten ◽  
Nicola Clemente ◽  
Luna Fogu ◽  
Evelina Pavarani ◽  
...  
Keyword(s):  
Seed Set ◽  
Germination Rate ◽  
Pollen Grains ◽  
Relative Effect ◽  
The Other ◽  
Pollen Load ◽  
Pollination Services ◽  
Ant Pollination ◽  
Negative Effect ◽  
Floral Visitors

Abstract Background and Aims Ant–plant associations are widely diverse and distributed throughout the world, leading to antagonistic and/or mutualistic interactions. Ant pollination is a rare mutualistic association and reports of ants as effective pollinators are limited to a few studies. Conospermum (Proteaceae) is an insect-pollinated genus well represented in the south-western Australia biodiversity hotspot, and here we aimed to evaluate the role of ants as pollinators of C. undulatum. Methods Pollen germination after contact with several species of ants and bees was tested for C. undulatum and five co-flowering species for comparison. We then sampled the pollen load of floral visitors of C. undulatum to assess whether ants carried a pollen load sufficient to enable pollination. Lastly, we performed exclusion treatments to assess the relative effect of flying- and non-flying-invertebrate floral visitors on the reproduction of C. undulatum. For this, we measured the seed set under different conditions: ants exclusion, flying-insects exclusion and control. Key Results Pollen of C. undulatum, along with the other Conospermum species, had a germination rate after contact with ants of ~80 % which did not differ from the effect of bees; in contrast, the other plant species tested showed a drop in the germination rate to ~10 % following ant treatments. Although ants were generalist visitors, they carried a pollen load with 68–86 % of suitable grains. Moreover, ants significantly contributed to the seed set of C. undulatum. Conclusions Our study highlights the complexity of ant–flower interactions and suggests that generalizations neglecting the importance of ants as pollinators cannot be made. Conospermum undulatum has evolved pollen with resistance to the negative effect of ant secretions on pollen grains, with ants providing effective pollination services to this threatened species.

Pathogen life-cycle leaves footprint on the spatial distribution of recruitment of their host plants

2020 ◽  
Vol 47 ◽  
pp. 100974
Author(s):  
Antonio J. Perea ◽  
José L. Garrido ◽  
Jose M. Fedriani ◽  
Pedro J. Rey ◽  
Julio M. Alcántara
Keyword(s):  
Spatial Distribution ◽  
Life Cycle ◽  
Host Plants

Apparent Mutualism Between Verticordia nitens and V-Aurea (Myrtaceae) and Their Oil-Ingesting Bee Pollinators (Hymenoptera, Colletidae)

1993 ◽  
Vol 41 (3) ◽  
pp. 369 ◽  
Author(s):  
TF Houston ◽  
BB Lamont ◽  
S Radford ◽  
SG Errington
Keyword(s):  
Fatty Acids ◽  
Seed Set ◽  
Flower Colour ◽  
Sole Source ◽  
Solitary Bee ◽  
Insect Pollinators ◽  
Obligate Mutualism

The prominently-displayed flowers of Verticordia nitens and V. aurea are unattractive to most insect pollinators and yet apparently serve as the sole source of pollen and nectar for two species of solitary bee. Euryglossa (Euhesma) morrisoni forages exclusively on V. nitens and E. (E.) aureophila forages exclusively on V. aurea. These bees carry much pollen on their bodies and appear solely responsible for seed set of 9-31% of ovules, with negligible seed set by V. nitens in the absence of E. morrisoni. Each anther of both Verticordia species releases pollen in copious amounts of oil (pollenkitt) beneath a hood-like appendage which terminates in a spout. Female bees ingest the pollen-oil mixture by touching the appendages with their glossae, and nectar by lapping the floor of the hypanthium. Most of the oils are isopentyl esters of the fatty acids, palmitic, stearic, arachidic (the major component of V. nitens) and behenic (the major component of V. aurea). These oils, as well as significant amounts of glucose, fructose and proline, are also present in the crop of E. morrisoni. The ability ofE. morrisoni and E. aureophila to remove and utilise pollen, oil and nectar from the flowers, their effectiveness as sole pollinators, and flower colour mimicry by E. morrisoni, together suggest an obligate mutualism between these bees and their Verticordia hosts.

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