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No description available.

Ants are key players in ecosystem function, especially in the tropics, yet little is known about the diversity and behavior of tropical ant communities. In a lowland wet forest of La Selva, Costa Rica ants are the primary predators of over a third of the sizes of bird-dispersed seeds. Dominated by the tribes Attini, Pheidolini and Solenopsidini, 35-38 species of ant preyed on seeds or seed baits. This is the most diverse granivorous ant community yet recorded, with the high diversity associated with higher population densities, smaller colony sizes and smaller body sizes than North American granivorous ant communities. The size of a frugivore dropping is isometric with the size of the bird producing it, and decreases with rain. Ant predation on these droppings was highly variable in time and space. Discovery and recruitment to droppings increased with dropping size as predicted by simple models. However, partial predation of large droppings produced the highest seed mortality at intermediate-size droppings. Seeds were found in 29% of meter-square samples of ant nests, suggesting seed rain was not highly localized. Small droppings were used by the greatest variety of species--this corresponded to observations of ant aggression at the largest droppings. Niche breadth increased with body size for both seed size and microclimate. Large ants foraged in a greater range of Vapor Pressure Deficits than small ants, as predicted by the law of surface area to volume. Large ants also took a greater variety of seed sizes than small ants, aided through intraspecific size matching in the large species (mostly attines). The tendency for small ant species to have niches nested within those of large ant species highlights the need to understand how body size and colony size influence interactions in ant communities.

This thesis investigates the roles of embryonic and postembryonic neurogenesis in the transformation of the larval antennal center (LAC) into the adult antennal lobe (AL) in the brain of the sphinx moth Manduca sexta. By means of birthdating methods, postembryonic neurogenesis in the CNS was first observed in the brain of the mid-first larval instar, and then proceeded in an anterior-to-posterior pattern. Five stereotypic neuroblast nests (three lateral, two medial) were identified that appeared to be associated with the LAC. Cell death was observed shortly after onset of postembryonic neurogenesis from the mid-first larval instar until wandering stage W2. Fates of the five LAC-associated lineages were traced histologically with respect to the anterior, medial, and lateral cell groups (AC, MC, LC) of the AL. At pupal stage P3, the three lateral nests coalesce and give rise to the postembryonic component of the LC, which is clearly distinguishable by pupal stage P4. Nests D and E remain separate and give rise to the postembryonic components of the AC and MC, respectively. A pronounced sexual dimorphism in the number of neurons in the MC was observed as early as pupal stage P5. The increased number of neurons in lineage E of males is evident as early as larval stage V-O, suggesting that regulation of postembryonic lineage size may contribute to the dimorphism of adults. The cellular distributions of two neuropeptide phenotypes (allatotropin-like-immunoreactivity, ATIR; and FMRFa-like-immunoreactivity, FIR) were examined immunocytochemically in larval, pupal and adult olfactory regions. Both phenotypes were found in a small number of cells lateral to the LAC, but significantly greater immunostaining was observed in the LC of the AL. For both ATIR and FIR, double-label immunocytochemistry (using BrdU) demonstrated that a subpopulation of the cells observed in the adult are born postembryonically. The larval and adult positions of ATIR and FIR neurons, of an identified serotonin-immunoreactive neuron, and of the five neuroblast nests, were compared. In every case, the lateral position of cells with respect to the LAC neuropil, regardless of embryonic or postembryonic origin, predicts a positional fate in the LC of the AL.

Haloxyfop-methyl, methyl-2-[4-[[3-chloro-5-(triflouromethyl)-2-pyridinyl]oxy]phenoxy]propanoic acid] and fluazifop-butyl, (+)-butyl-2-[4-[[5-(trifluoromethyl)-2-pyridinyl] oxy]phenoxy]propanoic acid are used for selective control of annual and perennial gramineous weeds in broadleaf crops. Annual blue grass (Poa annua L.) is controlled by haloxyfop-methyl but not by fluazifop-butyl. Research was conducted to determine the effect of each herbicide on growth, morphology, lipid synthesis and acetyl-CoA carboxylase activity, of this species, and to determine physiological mechanism of annual blue grass tolerance to fluazifop-butyl. Techniques used in this research were growth measurements, light and electron microscopy, TLC, and enzyme assay for acetyl-CoA carboxylase. Haloxyfop-methyl at 15 μM when applied preemergence caused 96% reduction of root growth of annual blue grass whereas fluazifop-butyl at 15 μM caused 42% reduction of root growth. Haloxyfop-methyl at 5 μM and 15 μM caused 35 and 96% inhibition of leaf growth, respectively. Fluazifop-butyl at same rates caused 19 and 32% inhibition of leaf growth. Haloxyfop-methyl at 5 and 20 μM when applied postemergence caused 20 and 56% reduction of leaf growth, respectively. Fluazifop-butyl at same rates caused 11 and 21% reduction of leaf growth. Haloxyfop-methyl at 20 μM caused 80% reduction of annual blue grass seedlings dry weight whereas fluazifop-butyl caused 40% reduction. Morphological studies showed that postemergence applications of 20 μM of haloxyfop-methyl caused severe tissue injury whereas same rates of fluazifop-butyl caused less injury. Ultrastructural studies showed that haloxyfop-methyl at 20 μM caused disruption, elongation, and reduction of chloroplast thylakoids whereas fluazifop-butyl caused less injury to thylakoids. Acetyl-CoA carboxylase activity from annual blue grass was inhibited by about 40% in the presence of 10 μM haloxyfop acid but fluazifop acid caused 6.5% inhibition. The lipid content was reduced by 56% in seedling treated with 20 μM haloxyfop-methyl whereas fluazifop-butyl caused 19% inhibition. Fluazifop-butyl at all rates caused no loss of lipid classes whereas haloxyfop-methyl at 10 and 15 μM caused loss of phospholipid and glycolipid which are part of the cellular membranes. Haloxyfop caused greater reduction of leaf and root growth, greater degree of tissue injury and chloroplast distortion, greater inhibition of acetyl-CoA carboxylase activity than fluazifop. All these effects lead to degradation of cellular components and eventually to the death of the plant.

No description available.

No description available.

No description available.

<p> Streams along the Copper River Delta, southcentral Alaska, exhibit contrasting thermal and hydrologic variability associated with being primarily groundwater-fed (GWF) or surface water-fed (SWF). Groundwater-fed streams are predictable both thermally and hydrologically year round, whereas SWF streams are unpredictable and exhibit more variable thermal and hydrologic regimes. These differences may strongly influence aquatic insect community structure and secondary production. Four streams, two GWF and two SWF, were sampled twice monthly from late April 2013 through August 2013 and once seasonally in fall (September) and early winter (November). Aquatic insect community structure differed markedly in both hydrologic types. Taxa richness was significantly higher in SWF (43) than in GWF (39) streams and non-metric multidimensional scaling of community structure revealed two distinct groups corresponding to the two hydrologic types. Total secondary production was higher in GWF than in SWF streams with Orthocladiinae (Diptera: Chironomidae) representing 56% of insect secondary production in GWF streams. Results from this study have strong implications for aquatic insect communities in GWF and SWF streams because of differing susceptibilities of these systems to the potential effects of climate change. Due to their thermal stability, groundwater-fed streams are less likely to be impacted by climate change, whereas SWF streams are thermally variable and more likely to be influenced. The effects of altered aquatic insect communities can cascade to higher trophic levels such as salmon and ultimately impact stream ecosystem function and the ecosystem services they provide.</p>

This thesis deals with the synthesis of conjugated dienicand trienic pheromone components- C12-C16alcohols, acetates and aldehydes and theirapplications in pheromone communication studies. Insect pheromones are widely used in modern pest management.The development of effective tools for plant protection is aresult of complex broad, interdisciplinary basic and appliedresearch. A practical use of pheromones for pest managementusually requires that specific active chemicals must beisolated,identified and produced synthetically. The creationof pheromone materials besides requires the identification ofthe active components, determination of the roles of otherpossible isomers or degradation products, the design ofdispensers of suitable substrates and evaporationparameters. The aim of the thesiswas critically to survey methods for the syntheses ofconjugated polyenic compounds and to focus to the synthesis ofseveral conjugated polyenic pheromone components providingsufficient quantities of chemically and isomerically purecompounds for bioassaying. The principal objective of the thesiswas concerned withthe further aim of developing effective synthetic materials forplant protection. The work was focussed: =&gt;To identify the compoundscollected from the leafminer mothPhyllonorycter emberizaepenella(Lepidoptera:Gracillaridae) and perform a detailed identification of thepheromones of the Brazilian apple leafrollerBonagota cranaodes(Meyrick) (Lepidoptera: Tortricidae)and of the codling mothCydia pomonella(L.) (Lepidoptera: Tortricidae). =&gt;Tostudy the effect of non-pheromonal isomers of the mainpheromone component on the sex attraction of B. cranaodes andC.pomonellain wind tunnel and field tests.=&gt;To study the role of identified pheromonecomponents in the pheromone communication of the currant shootborer Lampronia capitella (Cl.) (Lepidoptera: Prodoxidae), andto design and optimize the dispenser for effective trapping.=&gt;To investigate the presence of sex pheromonecomponents in the tobacco hawk mothManduca sexta(L.) (Lepidoptera: Sphingidae). The syntheses of four geometrical isomers of3,5-dodecadienyl acetate; (10E,12E,14Z)- and(10E,12E,14E)-(10,12,14)-hexadecatrien-1-als;(E,Z)-, (Z,E)-,and (Z,Z)-8,10-dodecadienol, codlemone acetate and aldehyde;(9Z,11Z)-9,11-tetradecadienol, corresponding acetate andaldehyde; all geometrical isomers of 8,10-and10,12-tetradecadienols and corresponding acetates wereperformed to ensure all these bioassays with syntheticpheromone components. All compounds were made in high chemicaland stereochemical purity, most of them more than 99%isomerically pure or by using several separation andpurification techniques. The suitable synthetic schemes for the synthesis of all fourgeometrical isomers of four conjugated dienic pheromonecomponents are presented in this thesis. The reactions and purification methods used here exemplifythe wide range of possibilities realized for such syntheses:they present the successful application of many syntheticmethods. The importance of this synthetic work is that thecompounds synthesized are not commercially available or on theother hand the purity of the purchasable compounds is notsatisfactory for research in the field of chemical ecology. Key words:Lepidoptera, sex pheromone, pheromonedispenser, 3,5-dodecadienyl acetate, 10,12,14-hexadecatrienal,8,10-dodecadienol, codlemone atsetate, codlemone aldehyde,8,10- tetradecadienol, 8,10-tetradecadienyl acetate,10,12-tetradecadienol, 10,12-tetradecadienyl acetate,Lampronia capitella, Manduca sexta, Bonagota cranaodes,Cydia pomonella, Phyllonorycter emberizaepenella,conjugated polyenic pheromone, conjugated diene, MPLC,(9Z,11Z)-9,11-tetradecadien-1-ol,(9Z,11Z)-9,11-tetradecadien-1-al