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The rice leafroller Cnaphalocrocis exigua (Butler) in the only species of the rice leaf folder/roller complex in Fiji. It is one of the major rice pests in the country, its pest status being exacerbrated by the cultivation of high-yielding varieties with minimal pest resistance. Detailed studies on the biology of the moth, in particular on the development, emergence, mating and flight behaviour, effect of adult nutrition on fecundity, egg hatchability and longevity, effect of larval nutrition on larval survival, pupation, pupal weight, pupal eclosion, and fecundity, egg hatchability and longevity of resultant adults, parasitism, and population ecology of C. exigua were carried out in Fiji from 1985 to 1987, and from June to August 1990. This study showed that there are several parasitoids of C. exigua in Fiji, and of those the egg and larval parasitoids Trichogramma sp. and Trathala flavo-orbitalis (Cameron) respectively are significant biotic mortality factors. Their impact as natural suppressors of C. exigua in fields of high yielding rice varieties was, however, inadequate to prevent C. exigua reaching damaging levels. Since C. exigua responds strongly to rice varietal differences, plant nitrogen status, and seasonal factors, is suspected to utilise pheromones during mating, and has numerous biocontrol agents in South East Asia and the Philippines, it appears to be an excellent candidate for an integrated pest management (IPM) program in Fiji. Before IPM strategies can be formulated, however, further investigations on rice varietal resistance, exploitation of exotic parasitoids and pathogens, and detailed studies on the possible presence of sex pheromones need to be conducted. / Doctor of Philosophy (PhD)

New Zealand�s fourteen deep-water fiords have complex physical and hydrographic features as well as strong environmental gradients, all of which may influence the population structure of organisms that inhabit the fiords. I examined the population structure of the brachiopod Terebratella sanguinea over ecological and evolutionary time scales in relation to physical and hydrographic features of the fiords. To further explore the role of larval dispersal in this system, comparisons between population genetic structure of T. sanguinea and a brachiopod with a contrasting larval dispersal strategy (Liothyrella neozelanica) were made. Aspects of the life history of the articulate brachiopod Terebratella sanguinea were measured. I measured density and size throughout Doubtful Sound and growth at outer (5 km from outer coast) and inner fiord sites (13.5 km from outer coast). Additionally, reproductive periodicity was measured at a single site within Doubtful Sound. Terebratella sanguinea occurred at significantly lower densities and was significantly smaller at the outer fiord site (p < 0.05), however growth rates between an inner and outer fiord site did not differ significantly. Terebratella sanguinea was found to have separate sexes and synchronous maturation of oocytes with spawning occurring in the austral winter. These results indicated that, on an ecological time scale, the environmental gradient of the fiords influences aspects of T. sanguinea population structure. In order to determine the influence of the fiord environment on genetic population structure, patterns among T. sanguinea from across Fiordland were assessed using two genetic markers, and these data were compared to hydrodynamic variables. Ten sites (322 individuals) were included in a preliminary allozyme analysis, and 20 sites (358 individuals) were used for the amplified fragment length polymorphism (AFLP) analysis. Patchy genetic differentiation was revealed with both markers, and a break between Long Sound and the other Fiordland sites was detected with AFLP markers. My results suggest hydrodynamic features of this region may isolate organisms that can disperse only during a planktonic larval phase, however this isolation is visible in genetic patterns only at the most extreme values of the hydrodynamic variables. To better understand how the fiord environment influences population structure of organisms that disperse via planktonic larvae, I compared population genetic structure of two sympatric brachiopod species that differ in planktonic larval duration. Genetic analysis using the AFLP technique revealed population structuring corresponding to the contrasting modes of larval dispersal. AMOVA analysis indicated Liothyrella neozelanica, a brachiopod that broods its larvae, had more limited exchange among sites within a fiord than did T. sanguinea, a brachiopod that does not brood its larvae. In general, the fiord hydrographic conditions may be creating opportunities for local genetic differentiation (for example Long Sound) in organisms capable of longer distance dispersal, but organisms with lower potential for dispersal are more strongly influenced by ontogeny than by hydrography. Understanding the population structure of some of the marine fauna of Fiordland is an important cornerstone for the developing management plan for the area. Conservation of the underwater resources of this World Heritage Area can be successful if the structure of the system and the mechanisms driving this structure are taken into account.

The purpose of this study was twofold: 1) to identify commercially available feeds that could serve as suitable replacements for newly hatched Artemia in the diets of L. vannamei from Z3/M1 to PL10 without significantly affecting survival, final length and weight, and quality of the larvae and 2) to identify an ideal substitution rate between live Artemia and a replacement feed that maximizes feed and labor costs savings, survival, and PL quality. In Experiment 1, two commercially available Artemia replacement feeds, Zeigler EZ Artemia and Bernaqua Vitellus, were administered according to manufacturer’s guidelines in order to identify which feed served as a more suitable replacement diet. In Experiment 2, the more successful feed from Experiment 1 was administered in three different co-feeding strategies, in which the inert feed replaced a certain percentage of live Artemia. Mean percent survival was not significantly different between the Control, EZ Artemia, and Vitellus treatment groups in Experiment 1 (P<0.05). Both the EZ Artemia and Vitellus treatments yielded significantly different final mean lengths (mm) and weights (mg) from the Control group. The Vitellus feed results for all performance factors (mean percent survival, final length (mm), final weight (mg), and percent stress test mortality) were not significantly different than those of the EZ Artemia treatment, despite receiving no Artemia during the culture period, while the EZ Artemia treatment received 75% Artemia from PL5-PL10. For these reasons, the Vitellus feed was selected as the more successful feed in Experiment 1. In Experiment 2, there was no significant difference between the four treatment groups (Control, V50, V100/50, and V100/75) for mean percent survival and percent stress test mortality (P<0.05). The V100/50 and V100/75 treatments’ mean final lengths (mm) and weights (mg) were significantly different than those of the Control treatment. There were no significant differences between the V50, V100/50, and V100/75 treatments for any of the observed performance factors. These results indicate that the maximum substitution rate of Vitellus for Artemia in this experiment (the V100/75 treatment) was successful in replacing 84.33% of newly hatched Artemia in the larval culture of L. vannamei from Z3/M1-PL10 without resulting in significantly different survival and stress test mortalities compared to the Control group. Feeding schedules such as V100/75 treatment help streamline production efforts in commercial operations and result in increased production cost savings when compared to other replacement feeding schedules that begin in the early mysis stages. The V100/75 feeding schedule influences variable feed and labor costs the greatest because farmers are able to delay the culturing of Artemia an additional 7 days (until PL5) from what is typically performed in larviculture facilities.

Many pathogen infections in nature are accompanied by injury and subsequent coagulation. Despite the contribution of hemolymph coagulation to wound sealing, little is known about its immune function. Based on the molecular knowledge of Drosophila innate immunity, this thesis investigated the immune function of clot both in vitro and in vivo, the immune relevant genes involved in a natural infection model, involving entomopathgenic nematodes (EPN) and the factors leading to crystal cell activation. Transglutaminase (TG) and its substrate Fondue (Fon) have been identified as bona fide clot components in Drosophila larvae. By knocking down TG or Fon via RNAi, we observed an increased susceptibility to EPN in larvae. In addition, this increased susceptibility was associated with an impaired ability of hemolymph clots to entrap bacteria. Immunostaining revealed that both clot components (Fon and TG) were able to target microbial surfaces. All these data suggest an immune function for the Drosophila hemolymph clot. Strikingly, similar results were obtained when we ran parallel experiments with human FXIIIa, an ortholog of Drosophila TG, indicating a functional conservation. We also found evidence for the regulation on both clot and immunity by eicosanoids in Drosophila larvae. The combination of EPN infection with the Drosophila model system allowed us to discover an immune function for TEP3 and Glutactin. However the molecular mechanism underlying the involvement of these two proteins in this particular host-pathogen interaction remains to be elucidated. Prophenoloxidase, the proform of enzyme involved in hardening the clot matrix, has been shown to be released by rupture of crystal cells. This cell rupture is dependent on activation of the JNK pathway, Rho GTPases and Eiger. Our work further identified the cytoskeletal component, Moesin, and the cytoskeletal regulator Rac2 as mediators of cell rupture. Despite the possible role of caspases in crystal cell activation, such cell rupture was turned out to be different from apoptosis. The implication of Rab5 in this process indicated that proper endocytosis is required for cell activation and subsequent melanization. Our findings furthered not only our understanding of the release of proPO via cell rupture but also our knowledge on different paths of immune cell activation. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: In press. Paper 4: Manuscript.<strong></strong></p>

The main objectives of this study is to :¡]1¡^probe into relationship of larval fish communities and environmental water factor in Tan-sui River Estuary, and observe assemblages of larval fish within different time scale¡F¡]2¡^to compare the results of DNA barcode with mophorlogical identification in larval and juvenile¡F¡]3¡^conjecture the recruit phase & the early life cycles of DNA indentified fish groups associated estuaries in Tan-sui. It shows that recruitment family, such as Scorpaenidae, Engraulidae, Sciaenidae, Sillaginidae and Gobiidae are the main fish have significant differences between larval fish community and the four seasons in Tan-sui estuary. Besides, statistical informations show community distribution and most environmental factors have significant differences, but temperature is the most. We compare the communities of twenty years ago, spring, autumn or summer are the opportune time of recruitment, 72 and 31 families of fish larvae were collected over past five and twenty years ago respectively, it shows that Tan-sui estuarine environment have been improved. We used 96 COI sequences in DNA indetification. Comparing the results of specimens identification between DNA barcoding and different morphological resolution power, DNA barcoding could up to the lower level than the tradiontional way. And after counting, the success rate of DNA identification was higher than different morphological resolving power¡Fthe numbers of mophological type are higher than the taxa after DNA indetification, it means that many morphological characters are not constant in early developmental stage, and DNA barcoding can be a useful tool to assist in promoting the success rate of the traditional way. Comparing with references, 34 indentified by DNA Barcode can conjecture recruit phase & early life cycles, most of these specimens are categorized to¡unondependent marine fish¡v, and the others are¡udependent marine fish¡v, but in fact, some of¡utrue estuarine¡v¡B¡ufeshwater¡vand ¡udiadromous¡vspecies can be indetified by morphology, it was due to the incompletion of the sequence database or sampling error. We should be able to understand the early life history of fish and the role of local habitat for the resources conservation and managenment in the future as long as we collect more complete COI database.

This study investigates the tempo-spatial distribution in species composition and abundance of planktonic pteropods in relation to hydrography in the waters around Liu-chiu Yu Island, southwestern Taiwan from February 2006 to October 2007. In total, we recognized 25 pteropod species belonging to 12 genera and six families, with a mean abundance of 7348 ¡Ó 994 ind./ 1000m3. The five most dominant species were Limacina inflata, Creseis virgula var. conica, Creseis acicula, Limacina trochiformis and Creseis clava, together they accounted for 78.7 % of the total pteropods. The surface sea water temperature, salinity, and phytoplankton concen- tration in the waters around Liu-chiu Yu Island were significantly higher in 2006 than in 2007. Pteropod abundance was higher in spring than in other seasons, and higher in deeper waters than in surface waters. Species number of pteropods was significantly higher in 2007 than in 2006, generally higher in summer and lower in autumn, and higher in deeper waters than in surface waters. Species diversity index of pteropods was generally higher in summer and lower in autumn. Cluster analysis of hydrography included 4 clusters (e.g., 2007 summer, summer and autumn, spring and winter, spring), the 2007 summer cluster was different from other seasons. Pteropod assemblage showed apparent difference between seasons, the variation of pteropod assemblages between stations in spring was higher than other seasons. Linear regression showed that the species number (p < 0.01) and diversity index (p < 0.05) were positively correlated with abundance of fish larvae. Abundance of most dominant species of pteropods was significantly and positively correlated with abundance of fish larvae (e.g., Limacina inflata; Creseis virgula var. conica and Limacina trochiformis) and significantly and negatively correlated with phytoplankton abundance (e.g., Limacina inflata, p < 0.001). In addition to the hydrographic factors, the distribution of pteropods might also be affected by predatory fish larvae and phytoplankton supplement.

Sponge population partly depends on larval recruitment. Environmental factors, e.g. light, salinity, pH and temperature, chemical factors and pollution may influence larval settlement and metamorphosis. In this study, the effects of galaxolide¡]HHCB¡^¡Btonalide¡]AHTN¡^and bisphenol A¡]BPA¡^on the settlement and metamorphosis of an intertidal sponge ¡]Spongia ceylonensis¡^ were examined. The experiments included LC50 test, effects of solvent, HHCB, AHTN and BPA on sponge settlement and metamorphosis. In the LC50 tests, the 96 hr¡VLC50 value of HHCB and AHTN all greater than 1.00 mg/L, and the 96 hr¡VLC50 of BPA was 0.58 mg/L. Acetone concentration (1.00 mg/L ) in this study didn¡¦t affect sponge settlement and metamorphosis. Effect of HHCB and AHTN on sponge settlement and metamorphosis concentrations of 0.13, 0.25, 0.50 and 1.00 mg/L was insignificant. In contrast, the settlement rate was decrease by 20 % at treatment of 1.00 mg/L BPA. The metamorphosis rates were also decrease by 20 % and 80 % at concentrations of 0.50 mg/L and 1.00 mg/L BPA. In conclusion, the toxicity of AHTN was greater than that of HHCB to sponge settlement and metamorphosis.

Larval recruitment is influenced by intrinsic biological traits (e.g. swimming behavior) and environmental factors. In this study, I examined the effects of environmental factors (e.g. light, temperature, salinity and pH) on the development of an intertidal keratose sponge from Peng-hu. The experiments included species identification, the observation of larval development, effects of environmental factors on larval choice and development. Based on morphological characters and the mitochondrial COI (cytochrome c oxidase subunit I) gene, the sponge is identified as Spongia ceylonensis which is viviparous. Sponge larva is a typical lecithotrophic, tufted parenchymella, about 500 £gm long and ovoid in shape. The mean swimming speed was 3.9 ¡Ó 0.6 sec/cm. Under natural light condition (3500 ¡V 6500 lux), planktonic stage was 5-6 hours. In the vertical dark/light choice experiments, larvae exhibited a negative phototaxis with larvae distributed in dark areas in all treatments except the light-treated group. A significant shorter time period for metamorphosis in the light-treated group than all other groups (all dark, upper-half dark and lower-half dark) (p < 0.0001) had been observed. Under various light gradients of single light source, i.e. fluorescent, non-UV, UVA, UVB or UVC light, larvae preferred in the darkest area. Under various light sources (fluorescent, non-UV, UVA, UVB and UVC lights) with the same intensity (220 ¡Ó 10 lux), there was no significant differences (p > 0.05) in the distribution of larvae. In all, larvae had strong dark preference and no preference on different light sources. Under various environmental gradients of each experimental factor (i.e. pH 6.5 ¡V 9.0; temperature: 20 ¡V 40¢J; silica: 0.5 ¡V 20.5 mg/L) in all light or all dark conditions, larvae showed no significant preference (p > 0.05). In salinities of 5, 15, 25 and 45 psu, some larvae had abnormal development as ball formation or dead. At pH 8.0 and 8.2, sponge juveniles developed better than the groups of pH 7.0¡B7.5¡B8.5 and 9.0. In addition, there was no significant difference in larval development (p > 0.05) under various silica concentrations (i.e. SiO2 0¡B2.5¡B5.0¡B7.5¡B10.0 mg/L).

Haemonchus contortus is a nematode parasite that infects sheep and goats, and other ruminants, causing substantial economic loss throughout the world. Anthelmintic drugs are the primary method to control these parasites; however, resistance to all broad spectrum anthelmintics, including the newer avermectins and milbemycins, has been developing rapidly in nematode parasites. The mechanism of avermectin resistance is unknown, but previous studies indicate that at least four genes are involved. A single nucleotide polymorphism (SNP) in the Haemonchus contortus HG1 gene has been linked to ivermectin (IVM) and moxidectin (MOX) resistance. This gene encodes a GABA-gated chloride channel thought to control body muscle movement in H. contortus and mediates IVM and MOX paralysis. The present study was designed to determine whether there is an association between variation in this gene and the ability of H. contortus larvae to move in the presence and absence of MOX. The present study also investigated the difference between a laboratory strain (PF23) and an ivermectin resistant field strain (VHR29). Fourteen different MOX concentrations (ranging from 0.078nm to 156uM) and at least 200 third stage (L3) larvae for each concentration were investigated for each strain. An L3 larval motility assay was used to determine the movement phenotype of individual larva. Pyrosequencing was used to identify the genotype of each individual larva. The present study found that in the PF23 strain, the resistant heterozygote genotype GA protected against the effects of MOX, and that the protection was dose dependent. This was not the case, however, in the VHR29 field strain. For this strain, no protective effect of the HG1 variation was observed with moxidectin treatment. One reason for this may be that field strains are selected under higher drug pressure which favors a monogenic response. The present study has shown that while the HG1 variation does play a role in larval movement and resistance to MOX, this effect may be minor compared to other effects selected in the field.