Abundance, distribution and habitat preferences of the lizard species present on Motunau Island, off the Canterbury coast of New Zealand, were investigated. The aim of the study was to investigate the extent to which recent vegetation change on Motunau Island has effected the lizard community and what implications this has for the future management of the Island. Three species of lizard occur on Motunau Island; the common gecko (Hoplodactylus maculatus), common skink (Oligosoma nigriplantare polychroma) and spotted skink (O. lineoocellatum). Rabbits (Oryctolagus cuniculus) were present on the island from 1862 until their eradication in 1962. Since then, vegetation on the island has changed from being tussock-dominated to being dominated by exotic weeds. Data from lizard pitfall trap surveys carried out in 1967-75 by Tony Whitaker of the Department of Scientific and Industrial Research (DSIR) were compared with new pitfall trapping data to determine if changes in the lizard population had occurred in response to these vegetation changes. The abundance of O. n. polychroma and H. maculatus does not appear to change significantly. The distribution of these two species were significantly correlated but neither showed any preference for a particular type. The abundance of O. lineoocellatum was significantly greater in 1996/97 than in the earlier DSlR surveys. This could be a result of the vegetation becoming more open and more structurally complex since the early surveys. This would offer greater opportunities for O. lineoocellatum (which is strongly heliothermic) to thermoregulate and forage. O. lineoocellatum showed no consistent significant preference towards any habitat type, although they tended to be found more in 'margin' habitat. Research into pitfall trapping and the way lizard behaviour may influence pitfall trapping data needs to be undertaken as there is a possible trap bias in this study. Management of Motunau Island needs to ensure that a structurally complex environment is maintained to ensure high numbers of all three lizard species can continue to coexist.

This study investigated understorey management in Canterbury, New Zealand, apple orchards for the enhancement of populations of Dolichogenidea tasmanica (Cameron) (Braconidae) for leafroller (Lepidoptera: Tortricidae) biological control. The first objective was to determine the influence of understorey plants on the abundance of D. tasmanica and leafroller parasitism, and to investigate the mechanisms behind this influence. The second was to determine the most suitable understorey plants in terms of their ability to enhance parasitoid abundance, leafroller parasitism, parasitoid longevity, parasitoid fecundity and its ability to not benefit leafroller. Results from three consecutive field trials showed that buckwheat (Fagopyrum esculentum Moench), coriander (Coriandrum sativum L.), alyssum (Lobularia maritima (L.) Desv), and, to a lesser extent, broad bean (Vicia faba L.), enhanced parasitoid abundance and leafroller parasitism. The mechanisms behind the effects of understorey plants had previously been unexplored. However, results here showed that it was the flowers or the buckwheat that 'attracted' the parasitoid to the plant and not the shelter, aphids or microclimate that the plant may also provide. Providing flowering plants in the orchard understorey also increased immigration of parasitoids and enhanced parasitoids and enhanced parasitoid longevity and fecundity in the laboratory. In contrast, the understorey plants had no influence on the female:male ratio of D. tasmanica. Although coriander enhanced leafroller parasitism three-fold in field experiments compared with controls, it failed to enhance the longevity of both sexes of D. tasmanica in the laboratory compared with water-only. Broad bean significantly enhanced parasitoid abundance three-fold and significantly increased parasitism from 0% to 75% compared with the controls on one leafroller release date. However, laboratory trials showed that of male D. tasmancia but it did not enhance female longevity. Also, female D. tasmanica foraging on broad bean produced a total of only three parasitoid cocoons, but this result was based on an overall 6.5% survival of larvae to pupae or to parasitoid cocoon. Furthermore, results suggested that extrafloral nectar secretion decreased as the plants matured. Phacelia (Phacelia tanacetifolia Benth.) did not significantly enhance parasitism rate in the field compared with controls, and numbers of D. tasmanica captured by suction sampling were significantly lower in phacelia treatments compared with alyssum, buckwheat and control plots. Also, laboratory experiments showed that survival of D. tasmanica on phacelia flowers was equivalent to that on water-only and significantly lower than on buckwheat. These results suggest that phacelia does not provide nectar to D. tasmanica, only pollen, and therefore is not a suitable understorey plant for D. tasmanica enhancement in orchards. Buckwheat and alyssum showed the most potential as understorey plants for the enhancement of natural enemies. Buckwheat not only increased numbers of D. tasmanica seven-fold, but also increased numbers of beneficial lacewings (Micromus tasmaniae (Walker)) and hover flies (Syrphidae) captured on yellow sticky traps compared with the controls. It significantly increased leafroller parasitism by D. tasmanica from 0% to 86% compared with the controls (on one date only), and in the laboratory enhanced D. tasmanica longevity and increased fecundity compared with water-only. Similarly, alyssum significantly increased parasitism rate compared with controls, and two-fold more D. tasmanica were suction sampled in these plots compared with controls. It also enhanced longevity of both sexes of D. tasmanica compared with water, and showed the most favourable characteristics in terms of being of no benefit to leafrollers. This is because it was not preferred over apple by leafroller larvae and when they were forced to feed on it, it caused high mortality (94.3%) and low pupal weight (15 mg). Furthermore, alyssum did not enhance the number of fertile eggs produced by adult leafrollers compared with water only. However, further research is required to address the overall effect of buckwheat and alyssum on crop production and orchard management, including effects on fruit yield and quality, frost risk, disease incidence, soil quality, weeds and other pests. Also, research into the ability of these plants to survive in the orchard with little maintenance, and into the optimal sowing rates, would be useful. Sampling natural populations of leafroller within each treatment showed that damage from leafrollers and the number of leafroller larvae were respectively 20.3% and 29.3% lower in the flowering treatments compared with the controls. Furthermore, field trials showed up to a six-fold increase in leafroller pupae in controls compared with buckwheat and alyssum. This suggests that increasing leafroller parasitism rate from understorey management in orchards will translate into lower pest populations, although neither larval numbers/damage nor pupal numbers differed significantly between treatments. Trapping D. tasmanica at a gradient of distances showed that this parasitoid travels into rows adjacent to buckwheat plots, indicating that growers may be able to sow flowering plants in every second or third row of the orchard, and still enhance leafroller biocontrol while minimising the adverse effects of a cover crop. Sowing buckwheat and alyssum in orchard understoreys may enhance biological control of apple pests in organic apple production and reduce the number of insect growth regulators applied in IFP programmes. However, the challenge still remains to investigate whether conservation biological control can reduce leafroller populations below economic thresholds.

In the late 1980s the endangered Chatham Island oystercatcher (Haematopus chathamensis) (CIO) was estimated at less than 110 individuals. Endemic to the Chatham Islands, New Zealand, it was feared to be declining and, based on existing productivity estimates, in danger of extinction within 50-70 years. These declines were thought to be caused by numerous changes since the arrival of humans, including the introduction of several terrestrial predators, the establishment of marram grass (Ammophila arenaria) which changes dune profiles, and increased disturbance along the coastline. The New Zealand Department of Conservation has undertaken recovery planning and conservation management to increase CIO numbers since the late 1980s. Recovery planning raised some key research questions concerning the population dynamics, habitat selection, and breeding biology of Chatham Island oystercatcher (CIO), and the critical factors currently limiting the population. The objectives of this study were to collect and interpret data on: 1) population size, trends, and distribution across the Chathams, 2) basic breeding parameters, 3) recruitment and mortality rates, 4) habitat selection at the general, territorial and nest-site levels, 5) habitat factors that are correlated with territory quality, and 6) cues that elicit territorial behaviour in CIO.

Minimising the potential impact of forest management requires an understanding of the key elements that maintain forest diversity and its role in ecological processes. Invertebrates are the most diverse of all biota and play important roles in maintaining forest processes. However, little is known about invertebrates in New Zealand's beech forests or the degree to which selective beech harvest might impact on their diversity and ability to carry out ecosystem processes. Studying ecosystem responses to disturbance is considered vital for understanding how ecosystems are maintained. One of the main objectives of this research was to assess whether litter-dwelling invertebrates were susceptible to the impacts of selective harvest and, if so, whether they could be used as indicators of forest health. Changes in invertebrate diversity could have important implications for nutrient cycling and primary production in forests. Litter-dwelling invertebrates contribute to the process of decomposition by increasing the surface area of the leaves, mixing soil organic matter and by infecting leaf particles with soil microbes. This investigation into the function of invertebrates in beech forest was carried out in the context of ecological theories which relate diversity to ecosystem stability and resilience. A replicated study was established in Maruia State Forest (South Island, New Zealand) to assess the potential biotic and abiotic impacts of sustainable beech harvest. Litter-dwelling invertebrates and environmental factors were monitored during 1997, before harvest, to determine how much variability there was between study sites. Specifically, litter pH, light intensity, litter fall, litter temperature, moisture as well as invertebrate abundance and diversity were compared before and after selective harvest. On 17 January 1998, two to three trees were selectively harvested from three of the nine study sites. On 15 February 1998 a similar number of trees were winched over or felled manually to create artificial windthrow sites. The remaining three undisturbed sites were used as controls. Invertebrates belonging to the detritivore guild were assessed from litter samples and a series of litter-bags containing pre-weighed leaf litter which were placed in each of the sites to assess rates of litter decomposition. Millipedes (Diplopoda: Polyzoniidae, Schedotrigonidae, Dalodesmidae, Habrodesmidae, Sphaerotheridae), earthworms (Oligochaeta: Annelida), tipulid larvae (Diptera: Tipulidae), weevils (Coleoptera: Curculionidae), moth larvae (Lepidoptera: Oecophoridae, Tortricidae and Psychidae), slaters (Isopoda: Styloniscidae), Oribatid mites (Acarina: Cryptostigmata) and landhoppers (Crustacea: Amphipoda) were extracted from the litter-bags and their abundance and diversity was compared between the three treatments. Weight loss from the litter-bags and the carbon and nitrogen content of litter were used to measure the rate of decomposition in each treatment. An additional study investigated whether exclusion of invertebrates from leaf litter resulted in reduced rates of decomposition. The results indicated that there was an increase in light intensity and a small increase in temperature following selective harvest and artificial windthrow. There was no significant difference in litter moisture or the amount of litter fall between the treatments. Invertebrate abundances were significantly affected by season but did not appear to be affected by selective harvest or artificial windthrow. The diversity of invertebrates remained relatively constant throughout the year, as did the rate of decomposition. When invertebrates were excluded from the leaf litter there was no consequential effect on the rate of litter decomposition. This suggests that there may be compensatory mechanisms taking place between the trophic levels of the food web to maintain processes and that direct links between invertebrates and decomposition are relatively weak. In conclusion, it appears that the effects of selective beech harvest on forest-floor processes were minimal and are comparable to those created by natural windthrow disturbance. It also appears that macroclimatic effects such as seasonal climatic effects have a large effect on forest biota. As none of the invertebrates studied appeared to be detrimentally affected by selective harvest and as there was no direct link demonstrated with decomposition, it was considered inappropriate to advocate the use of this group of invertebrates as indicators of sustainable forest management. The results from this study provide information which may help inform decisions on the future management of diversity in beech forest ecosystems.

<p dir="ltr">Non-native biological invasions are one of the leading concerns for global biodiversity. The establishment of invasive species reduces local biodiversity, shifts species composition, changes successional trajectories, and alters ecosystem functions. This thesis examines two aspects of invasive plants: (1) the distribution and the most important climatic and anthropogenic drivers of invasive trees across the eastern United States, and (2) an evaluation of invasive plant removal and herbaceous recovery from a government cost-share program that provides financial support for invasive plant management by private landowners.</p><p><br></p><p dir="ltr">Our first study focused on identifying the distribution of invasive trees, and the factors associated with their distribution. This is essential to predicting spread and planning subsequent management. Using USDA Forest Inventory Analysis (FIA) data and random forest modeling, we examined the distribution, and variables associated with the distribution, of invasive tree species. Invasive trees were found in 10,511 out of 299,387 FIA plots. Invasive species basal area and density (trees per ha; TPH) were highest within the central and southern Appalachian Mountains, Michigan, the Northeast, and the southern Coastal Plain of the United States. A random forest model of invasive species basal area (R²= 0.47, RMSE = 0.47) and density (R²=0.46, RMSE=0.50) vs. environmental variables found that both invasive basal area and density were most strongly associated with human footprint, followed by various climatic variables. An equivalent model of native tree basal (R²=0.53, RMSE=9.25) and TPH (R²=0.47, RMSE=8.64) found that native tree basal area and density were most strongly associated with aridity followed by various climatic variables. As human footprint increased, invasive tree basal area and density increased. These results suggest that the distribution of invasive trees is reliant on human alterations to forests.</p><p><br></p><p dir="ltr">Our second study focused on Environmental Quality Incentives Program (EQIP), a federal cost-share program that has provided $25 billion of financial assistance to farmers and non-industrial private forest owners. Few studies have examined whether this program facilitates the recovery of the herbaceous layer while decreasing the dominance of invasive plant species. We surveyed the herbaceous layer of EQIP-treated and untreated (reference) forests across three physiographic regions of Indiana. Using non-metric multidimensional scaling (NMDS) ordination and linear mixed effects models, we evaluated the species composition, richness, diversity, evenness, floristic quality index, and herbaceous-layer cover of EQIP and reference sites. We also used linear mixed models to evaluate how EQIP site treatment affected the diversity of native plant species. Sites treated with EQIP contracts typically had significantly higher native species richness, Shannon’s diversity, and floristic quality than reference sites. There were significant separations in species composition between EQIP treated and reference forests state-wide and in the southern non-glaciated region of Indiana, although composition overlapped between EQIP and reference forests. Our study suggests that EQIP-funded treatments promote increased species richness and diversity. However, the persistent overlap in species composition we observed may signify biotic homogenization due to a long-shared history of anthropogenic disturbances between EQIP and reference sites. Therefore, active restoration of the herbaceous layer might be needed to allow a full recovery after invasive removal.</p>

<p>Land use change constitutes a primary driving force in shaping social-ecological systems world wide, and its effects reach far beyond the directly impacted areas. Graph based landscape ecological tools have become established as a promising way to efficiently explore and analyze the complex, spatial systems dynamics of ecological networks in physical landscapes. However, little attention has been paid to making these approaches operational within ecological assessments, physical planning, and design. This thesis presents a network based, landscape-ecological tool that can be implemented for effective use by practitioners within physical planning and design, and ecological assessments related to these activities. The tool is based on an ecological profile system, a common generalized network model of the ecological infrastructure, graph theoretic metrics, and a spatially explicit, geographically defined representation, deployable in a GIS. Graph theoretic metrics and analysis techniques are able to capture the spatio-temporal dynamics of complex systems, and the generalized network model places the graph theoretic toolbox in a geographically defined landscape. This provides completely new insights for physical planning, and environmental assessment activities. The design of the model is based on the experience gained through seven real-world cases, commissioned by different governmental organizations within Stockholm County. A participatory approach was used in these case studies, involving stakeholders of different backgrounds, in which the tool proved to be flexible and effective in the communication and negotiation of indicators, targets, and impacts. In addition to successful impact predictions for alternative planning scenarios, the tool was able to highlight critical ecological structures within the landscape, both from a system-centric, and a site-centric perspective. In already being deployed and used in planning, assessments, inventories, and monitoring by several of the involved organizations, the tool has proved to effectively meet some of the challenges of application in a multidisciplinary landscape.</p>

In this study, buckwheat (Fagopyrum esculentum Moench) and alyssum (Lobularia maritima (L.)) flowers were used to examine the effect of floral resources on the efficacy of the leafroller parasitoid Dolichogenidea tasmanica (Cameron) in vineyards. This was done by assessing the influence of these flowers on parasitoid abundance and parasitism rate, and by investigating the consequences of this for leafroller abundance. In laboratory experiments, alyssum flowers were used to investigate the effect of floral food on the longevity, fecundity and sex ratio of D. tasmanica. Dolichogenidea tasmanica comprised more than 95 % of parasitoids reared from field collected leafrollers in this study. The abundance of D. tasmanica during the 1999-2000 growing season was very low compared with previous studies, possibly due to the very low abundance of its leafroller hosts during the experiment. The number of males of this species on yellow sticky traps was increased (although not significantly) when buckwheat flowers were planted in a Marlborough vineyard; however, the number of female D. tasmanica on traps was no greater with flowers than without. The abundance of another leafroller parasitoid, Glyptapanteles demeter (Wilkinson)(Hymenoptera: Braconidae), on traps was also not significantly affected by the presence of buckwheat flowers, although females of this species were caught in greater numbers in the control than in buckwheat plots. Naturally-occurring leafrollers were collected from three vineyard sites in Marlborough, and one in Canterbury during the 2000-2001 season to assess the effect of buckwheat and alyssum flowers on parasitism rate. Parasitism rate more than doubled in the presence of buckwheat at one of the Marlborough vineyards, but alyssum had no effect on parasitism rate in Canterbury. A leafroller release/recover method, used when naturally-occurring leafrollers were too scarce to collect, was unable to detect any effect of buckwheat or alyssum on parasitism rate. Mean parasitism rates of approximately 20 % were common in Marlborough, although rates ranged from 0 % to 45 % across the three vineyard sites in that region. In Canterbury in April, mean parasitism rates were approximately 40 % (Chapter 4). Rates were higher on upper canopy leaves (40-60 %) compared with lower canopy leaves and bunches (0-25 %). Leafroller abundance was apparently not affected by the presence of buckwheat in Marlborough, or alyssum in Canterbury. Buckwheat did, however, significantly reduce the amount of leafroller evidence (webbed leafroller feeding sites on leaves or in bunches) in Marlborough, suggesting that the presence of these flowers may reduce leafroller populations. Leafrollers infested less than 0.1 % of Cabernet Sauvignon leaves throughout the 1999-2000 growing season, but increased in abundance in bunches to infest a maximum of 0.5 % of bunches in late March in Marlborough. In Pinot Noir vines in the 2000-2001 season, leafroller abundance was also low, although sampling was not conducted late in the season when abundance reaches a peak. In Riesling vines in Canterbury, between 1.5 % and 2.5 % of bunches were infested with leafrollers in April. In the laboratory, alyssum flowers significantly increased the longevity and lifetime fecundity of D. tasmanica compared with a no-flower treatment. However, daily fecundity was not increased by the availability of food, suggesting that the greater lifetime fecundity was related to increases in longevity. Parasitoids were also able to obtain nutrients from whitefly honeydew, which resulted in similar longevity and daily fecundity to those when alyssum flowers were present. The availability of food had a significant effect on the offspring sex ratio of D. tasmanica. Parasitoids reared from naturally-occurring leafrollers produced an equal sex ratio, assumed to be the evolutionarily stable strategy (ESS) for this species. In the laboratory, this ESS was observed only when parasitoids had access to alyssum flowers. Without food, or with honeydew only, sex ratios were strongly male-biased. In the field, floral resources affected the sex ratio of D. tasmanica only when this species was reared from leafrollers released and recovered in Marlborough. In that experiment, buckwheat shifted the sex ratio in favour of female production from the equal sex ratio found in control plots. No firm explanations can be given to account for these results, due to a lack of research in this area. Possible mechanisms for the changes in sex ratio with flowers are discussed. This study demonstrated that flowers are an important source of nutrients for D. tasmanica, influencing the longevity, fecundity and offspring sex ratio of this species. However, only some of the field experiments were able to show any positive effect of the provision of floral resources on parasitoid abundance or parasitism rate. More information is needed on the role these parasitoids, and other natural enemies, play in regulating leafroller populations in New Zealand vineyards, and on how they use floral resources in the field, before recommendations can be made regarding the adoption of this technology by growers.

<p>Eastern black walnut (<i>Juglans nigra</i> L.) ranks among the most highly valued timber species in the central hardwood forest and across the world. This valuable tree fills a critical role in native ecosystems as a mast bearing pioneer on mesic sites. Along with other <i>Juglans</i> spp. (Juglandaceae), <i>J. nigra</i> is threatened by thousand cankers disease (TCD), an insect-vectored disease first described in 2009. TCD is caused by the bark beetle <i>Pityophthorus juglandis</i> Blackman (Corthylini) and the phytopathogenic fungus <i>Geosmithia morbida</i> Kol. Free. Ut. & Tiss. (Bionectriaceae). Together, the <i>P. juglandis</i>-<i>G. morbida</i> complex has expanded from its historical range in southwest North America throughout the western United States (U.S.) and Europe. This range expansion has led to widespread mortality among naïve hosts <i>J. nigra</i> and <i>J. regia</i> planted outside their native distributions.</p> <p> The severity of TCD was previously observed to be highest in urban and plantation environments and outside of the host native range. Therefore, the objective of this work was to provide information on biotic and abiotic environmental factors that influence the severity and impact of TCD across the native and non-native range of <i>J. nigra</i> and across different climatic and management regimes. This knowledge would enable a better assessment of the risk posed by TCD and a basis for developing management activities that impart resilience to natural systems. Through a series of greenhouse-, laboratory- and field-based experiments, environmental factors that affect the pathogenicity and/or survival of <i>G. morbida</i> in <i>J. nigra</i> were identified, with a focus on the microbiome, climate, and opportunistic pathogens. A number of potentially important interactions among host, vector, pathogen and the rest of the holobiont of TCD were characterized. The <i>holobiont</i> is defined as the whole multitrophic community of organisms—including <i>J. nigra</i>, microinvertebrates, fungi and bacteria—that interact with one another and with the host.</p> <p>Our findings indicate that interactions among host, vector, pathogen, secondary pathogens, novel microbial communities, and novel abiotic environments modulate the severity of TCD in native, non-native, and managed and unmanaged contexts. Prevailing climatic conditions favor reproduction and spread of <i>G. morbida</i> in the western United States due to the effect of wood moisture content on fungal competition. The microbiome of soils, roots, and stems of trees and seedlings grown outside the host native range harbor distinct, lower-diversity communities of bacteria and fungi compared to the native range, including different communities of beneficial or pathogenic functional groups of fungi. The pathogen <i>G. morbida</i> was also associated with a distinct community of microbes in stems compared to <i>G. morbida</i>-negative trees. The soil microbiome from intensively-managed plantations facilitated positive feedback between <i>G. morbida</i> and a disease-promomting endophytic <i>Fusarium solani</i> species complex sp. in roots of <i>J. nigra</i> seedlings. Finally, the nematode species <i>Bursaphelenchus juglandis</i> associated with <i>P. juglandis</i> synergizes with <i>G. morbida</i> to cause foliar symptoms in seedlings in a shadehouse; conversely, experiments and observations indicated that the nematode species <i>Panagrolaimus</i> sp. and cf. <i>Ektaphelenchus</i> sp. could suppress WTB populations and/or TCD outbreaks.</p> <p>In conclusion, the composition, function, and interactions within the <i>P. juglandis</i> and <i>J. nigra</i> holobiont play important roles in the TCD pathosystem. Managers and conservationists should be aware that novel associations outside the host native range, or in monocultures, intensive nursery production, and urban and low-humidity environments may favor progression of the disease through the effects of associated phytobiomes, nematodes, and climatic conditions on disease etiology. Trees in higher diversity, less intensively managed growing environments within their native range may be more resilient to disease. Moreover, expatriated, susceptible host species (<i>i.e.</i>, <i>J. nigra</i>) growing in environments that are favorable to novel pests or pest complexes (<i>i.e.</i>, the western U.S.) may provide connectivity between emergent forest health threats (<i>i.e.</i>, TCD) and native host populations (<i>i.e.</i>, <i>J. nigra</i> in its native range).</p>

Arthropod species that have the potential to damage crops are food resources for communities of predators and parasitoids. From an agronomic perspective these species are pests and biocontrol agents respectively, and the relationships between them can be important determinants of crop yield and quality. The impact of biocontrol agents on pest populations may depend on the availability of other food resources in the agroecosystem. A scarcity of such resources may limit biological control and altering agroecosystem management to alleviate this limitation could contribute to pest management. This is a tactic of ‘conservation biological control’ and includes the provision of flowers for species that consume prey as larvae but require floral resources in their adult stage. The use of flowers for pest management requires an understanding of the interactions between the flowers, pests, biocontrol agents and non-target species. Without this, attempts to enhance biological control might be ineffective or detrimental. This thesis develops our understanding in two areas which have received relatively little attention: the role of flowers in biological control by true omnivores, and the implications of flower use by fourth-trophic-level life-history omnivores. The species studied were the lacewing Micromus tasmaniae and its parasitoid Anacharis zealandica. Buckwheat flowers Fagopyrum esculentum provided floral resources and aphids Acyrthosiphon pisum served as prey. Laboratory experiments with M. tasmaniae demonstrated that although prey were required for reproduction, providing flowers increased survival and oviposition when prey abundance was low. Flowers also decreased prey consumption by the adult lacewings. These experiments therefore revealed the potential for flowers to either enhance or disrupt biological control by M. tasmaniae. Adult M. tasmaniae were collected from a crop containing a strip of flowers. Analyses to determine the presence of prey and pollen in their digestive tracts suggested that predation was more frequent than foraging in flowers. It was concluded that the flower strip probably did not affect biological control by lacewings in that field, but flowers could be significant in other situations. The lifetime fecundity of A. zealandica was greatly increased by the presence of flowers in the laboratory. Providing flowers therefore has the potential to increase parasitism of M. tasmaniae and so disrupt biological control. A. zealandica was also studied in a crop containing a flower strip. Rubidium-marking was used to investigate nectar-feeding and dispersal from the flowers. In addition, the parasitoids’ sugar compositions were determined by HPLC and used to infer feeding histories. Although further work is required to develop the use of these techniques in this system, the results suggested that A. zealandica did not exploit the flower strip. The sugar profiles suggested that honeydew had been consumed by many of the parasitoids. A simulation model was developed to explore the dynamics of aphid, lacewing and parasitoid populations with and without flowers. This suggested that if M. tasmaniae and A. zealandica responded to flowers as in the laboratory, flowers would only have a small effect on biological control within a single period of a lucerne cutting cycle. When parasitoids were present, the direct beneficial effect of flowers on the lacewing population was outweighed by increased parasitism, reducing the potential for biological control in future crops. The results presented in this thesis exemplify the complex interactions that may occur as a consequence of providing floral resources in agroecosystems and re-affirm the need for agroecology to inform the development of sustainable pest management techniques.

The sap beetle genus Carpophilus Stephens (Coleoptera: Nitidulidae) is a large genus consisting of over 200 species and are found worldwide. Several species are important pests of crops and stored products, and are frequently intercepted as part of biosecurity operations. The genus is poorly known taxonomically, and there are several species groups that are challenging to identify by morphological methods. In particular, two species found across the Pacific, C. maculatus Murray and C. oculatus Murray are frequently confused with each other. These two species are similar in size and colour, but differ primarily by the shape of the colour pattern on their elytra. However, this colour pattern is highly variable within both species, leading to ambiguity in the indentification of these species. Within C. oculatus, three subspecies have been described based on differences in the male genitalia and pronotal punctation: C. o. oculatus and C. o. gilloglyi Dobson are distributed widely across the Pacific, while C. o. cheesmani Dobson is known only from Vanuatu. A search of literature records and specimen collections revealed 32 species of Carpophilus recorded from the Pacific region. In addition there remain several unidentified specimens representing at least four species, two of which will be described subsequent to this research. A number of species recorded in the literature may have been misidentified, and these require further field collections and inspection of museum specimens to confirm their presence in the Pacific. To test the validity of the subspecies of C. oculatus, and its distinctiveness from C. maculatus, a phylogeny of available specimens of Carpophilus was inferred from one mitochondrial gene (cytochrome c oxidase subunit I (COI)), and two nuclear genes (28S ribsomal RNA (28S) and the internal transcribed spacer 2 (ITS2)). These data show large genetic distances between the three subspecies of C. oculatus of 7-12%. Given these distances are similar to those between other species in the genus, this indicates these subspecies may be elevated to full species. The data also consistently support a monophyletic relationship between C. o. oculatus and C. o. gilloglyi. Nuclear genes also support C. o. cheesmani as part of a clade with the other subspecies, but these relationships are unresolved in COI. Carpophilus maculatus was not supported as being the sister taxon of the C. o. oculatus and C. o. gilloglyi clade. Other relationships within Carpophilus were unresolved, possibly due to a combination of incomplete taxon sampling, and saturation of substitutions within the COI gene. Phylogeographic analysis of specimens collected from several localities within the range of C. oculatus showed that, with only one exception, there were no shared haplotypes between archipelagoes. This result suggests it may be possible to determine the provenence of intercepted specimens, providing further information regarding potential invasion pathways. A degree of geographic structuring was also present within C. o. gilloglyi, being separated into a western clade found in Fiji and Rotuma and an eastern clade distributed from the Kermadec Islands and Tonga to French Polynesia. This separation was most profound in COI data, with a mean pairwise distance between the clades of 7%. ITS2 data also demonstrates a degree of differentiation between the two clades, based on differences in the insertions and deletions between the clades. The variability in the shape and colour of the elytral pattern of C. oculatus was also investigated. Colour was quantified using a method based on Red-Green-Blue (RGB) colour values derived from digital photographs, while an outline analysis of the elytral pattern was conducted using elliptic Fourier analysis (EFA). Principal Components Analysis of the RGB values and EFA coefficients showed no clear separation between subspecies, nor were any trends correlated with host fruit or collection localities. Variation at all levels and all measures studied in this thesis show that this geographic region and this genus of beetles offer intruiging insights into speciation, biogeography and biological invasions. There is much scope for further research on the causes and consequences of this variation and the lives of these interesting insects.