The vegetable brassicas of cabbage, broccoli, and cauliflower are grown in Pukekohe for the Auckland fresh-produce markets. These brassicas are attacked by three major lepidopterous pests: diamondback moth (DBM) (Plutella xylostella (L)) (Yponomeutidae), white butterfly (WB) (Pieris rapae (L.)) (Pieridae), and soybean looper (SBL) (Thysanoplusia orichalcea (F.)) (Noctuidae). Current grower strategy to combat these pests is calendar-scheduled insecticide applications. The goal of this thesis is to develop pest management alternatives. The seasonality of these three pests is discussed. DBM and WB are each under biological control by a larval and a pupal parasitoid, but this natural control is not sufficient to allow economic harvests in cabbage and was not synchronized. No parasitoids of SBL were found. The importation of additional natural enemies is discussed. A scouting system of the percent of cabbage plants infested coupled with an action threshold of. 15%-20% infested plants, resulted in good yields in field trials and allowed up to a 50% reduction in insecticide applications over the growth period when compared to a 14-day calendar schedule. Implementation of the 15% infested threshold in commercial cabbage fields resulted in up to an 83% reduction in insecticide applications with no yield decrease in quality or quantity. Application of this 15% infested plant threshold to broccoli and cauliflower decreased insecticide applications by 40% and 17%, respectively. Study of larval biology indicated that all of the lepidopterans preferentially fed on leaves; timing of the first insecticide application in broccoli and cauliflower to coincide with floret initiation decreased insecticide applications by 80% and 67%, respectively. Laboratory and field trials comparing DBM oviposition preference, larval survivability, and parasitism rates between cabbage, broccoli, and cauliflower are discussed. Knowledge of lepidopterous pest seasonality and biology, linked to careful timing of insecticide applications to coincide with threshold levels of pests, can take full advantage of natural enemies and reduce insecticide input in the vegetable brassicas of cabbage, broccoli, and cauliflower with no decrease in crop quality.

Examination of the terminal abdominal ganglia of the New Zealand maritime earwig Anisolabis littorea (White) revealed a paraldehyde fuchsin stainable material in animals which had undergone some degree of dehydration. A Malpighian tubule bioassay preparation enabled the physiological activity of extracts of the terminal abdominal ganglia and pharmacologically actives substances to be monitored. Results obtained suggest that substances are present in the terminal abdominal ganglia which alter the Malpighian tubule secretion rate. These results are discussed in view of current theories of Malpighian tubule secretion in insects.

The vegetable brassicas of cabbage, broccoli, and cauliflower are grown in Pukekohe for the Auckland fresh-produce markets. These brassicas are attacked by three major lepidopterous pests: diamondback moth (DBM) (Plutella xylostella (L)) (Yponomeutidae), white butterfly (WB) (Pieris rapae (L.)) (Pieridae), and soybean looper (SBL) (Thysanoplusia orichalcea (F.)) (Noctuidae). Current grower strategy to combat these pests is calendar-scheduled insecticide applications. The goal of this thesis is to develop pest management alternatives. The seasonality of these three pests is discussed. DBM and WB are each under biological control by a larval and a pupal parasitoid, but this natural control is not sufficient to allow economic harvests in cabbage and was not synchronized. No parasitoids of SBL were found. The importation of additional natural enemies is discussed. A scouting system of the percent of cabbage plants infested coupled with an action threshold of. 15%-20% infested plants, resulted in good yields in field trials and allowed up to a 50% reduction in insecticide applications over the growth period when compared to a 14-day calendar schedule. Implementation of the 15% infested threshold in commercial cabbage fields resulted in up to an 83% reduction in insecticide applications with no yield decrease in quality or quantity. Application of this 15% infested plant threshold to broccoli and cauliflower decreased insecticide applications by 40% and 17%, respectively. Study of larval biology indicated that all of the lepidopterans preferentially fed on leaves; timing of the first insecticide application in broccoli and cauliflower to coincide with floret initiation decreased insecticide applications by 80% and 67%, respectively. Laboratory and field trials comparing DBM oviposition preference, larval survivability, and parasitism rates between cabbage, broccoli, and cauliflower are discussed. Knowledge of lepidopterous pest seasonality and biology, linked to careful timing of insecticide applications to coincide with threshold levels of pests, can take full advantage of natural enemies and reduce insecticide input in the vegetable brassicas of cabbage, broccoli, and cauliflower with no decrease in crop quality.

Examination of the terminal abdominal ganglia of the New Zealand maritime earwig Anisolabis littorea (White) revealed a paraldehyde fuchsin stainable material in animals which had undergone some degree of dehydration. A Malpighian tubule bioassay preparation enabled the physiological activity of extracts of the terminal abdominal ganglia and pharmacologically actives substances to be monitored. Results obtained suggest that substances are present in the terminal abdominal ganglia which alter the Malpighian tubule secretion rate. These results are discussed in view of current theories of Malpighian tubule secretion in insects.

The species status and host range of Heliothis armigera was investigated. DNA profiling, mitochondrial DNA sequencing, RAPD's, along with traditional morphological and crossing methods were used to investigate micro, macro and mega-population structuring. Thirty-six new host records were added, of which a number are important common weeds and crops. Mortality due to parasitoids and fungal infections were quantified on many host species. Genetic analysis of the COII and the AT-rich regions of the mitochondrial DNA showed very high levels of variation, as did the DNA profiling using the probes (CA)n and 33.15. The morphological analyses also showed variation, but to a lesser degree and without statistical significance. The variation found at all levels and in all aspects is discussed with respect to caterpillar host-plants and geographical location. All host-plant populations of caterpillars showed very high levels of genetic variability. However, the population of caterpillars found on Sulla (Hedysarium coronarium) was significantly more variable than those found on Lotus and Lucerne when compared using DNA profiling. The sequences obtained from the two mtDNA regions also showed considerable variation, a great percentage of which was uninformative. This variation did not allude to any structuring of caterpillar populations with respect to host-plant or geographical location. H. armigera is genetically a very variable species which does not equate with any population structuring present in the host-plant or geographical populations investigated here. This study has greatly increased the general understanding of this insect, and has elucidated a portion of the genetic makeup, but not helped in the development any new control methods.

Although Argentine ant(Linepithema humile), a highly invasive ant species, has been in New Zealand for at least l4 years, little is known about their ecology and potential for invasion. Increasing spread and establishment of populations throughout New Zealand is disturbing because of the devastating impacts documented on native invertebrate biodiversity overseas. The primary aim of this study was to determine the impacts of Argentine ants on arthropods in native forest habitats in west Auckland. Pitfall traps at invaded and uninvaded sites were used to quantify ant and non-ant arthropod faunas. Argentine ants did not adversely affect native host ant communities. Moreover, two ant species appeared to be resistant to invasion. Argentine ant invasion reduced the abundance of a few orders of invertebrates while several taxa were more abundant in the presence of Argentine ants. Distribution and foraging activity of Argentine ant populations were monitored in this study from 2000-2003. Also, rate of spread was investigated to evaluate whether native forest habitats would be at risk from invasion. Measurements of foraging ant trails on monitored tree trunks revealed seasonal distribution patterns involving high activity in summer/autumn and low activity in winter/early spring. Argentine ants were found to be established primarily along the edge of the forest and did not invade into the interior of the forest during the study period. An Argentine ant poisoning operation on Tiritiri Matangi Island in January 2001 provided the opportunity to document the results of the eradication trial. In addition, pitfall traps placed at two treated sites and one untreated site were used to compare pre-poison and post-poison effects on ant and non-ant invertebrate communities. Fipronil baiting at 0.01% effectively reduced Argentine ants at the study sites and very few ants were observed in both tree count and pitfall trap recordings two months after poisoning. The invasion of Argentine ants on Tiritiri Matangi Island decimated native host ants and no recovery was detected throughout the study. Several groups of invertebrates appeared to benefit from the removal of Argentine ants while a few showed no detectable changes. Conservation implications resulting from the findings of this study are discussed Also, potential future research involving Argentine ants are outlined.

Aphidius ervi Haliday is a cosmopolitan parasitoid species of several major aphid pests on economically important crops. Prior to this research, little information was available on its reproductive behaviour. Emergence of A. ervi peaks during the first few hours of the photophase with males being protandrous. Females become sexually mature earlier than males and oviposit primarily in the photophase. Aphids parasitised in their early instars die before reproduction but those parasitised in later instars produce a limited number of progeny. Females prefer aphids of 3- to 5-d-old over the younger and older aphids for oviposition. Females ovipositing in 4- to 7-d-old aphids have more fitness gains in terms of progeny body size and egg load at emergence. Fertilised eggs are more likely deposited in large hosts and unfertilised eggs in small ones. Large individuals have greater longevity, large males father more progeny, and large females have higher fecundity, parasitism and greater ability in host searching. However, with increasing body size females gain more than males in longevity and fecundity but males gain more than females in the number of female progeny. Males can inseminate up to nine females and they carry about 82% effective sperm at emergence and replenish about 18% sperm during their adult life. Females adjust the oviposition and sex allocation strategies in response to increasing host density with higher number of aphids parasitised at higher host densities and lower proportion of female progeny produced at lower host densities. Males play an active role in mating behaviour. Males having mating experience, and being large or younger, respond to females more quickly and perform better courtships resulting in higher mating success. Males prefer larger and younger females for mating probably because the latter have greater reproductive potential. Males optimize the use of their sperm based on the availability of their sperm and the reproductive status (age) of females. The switchingoff of female receptivity of male mating attempt after the mating is a gradual process. Some females accept the second males within 1 minute since the termination of the first mating. The shorter mating period in the second mating suggests that females remate probably due to the gradual process of switching-off of female receptivity rather than the insufficient sperm transformation during the first mating. Males prolong their mating duration in male-biased operational sex ratio to reduce the probability of female remating.

Aphidius ervi Haliday is a cosmopolitan parasitoid species of several major aphid pests on economically important crops. Prior to this research, little information was available on its reproductive behaviour. Emergence of A. ervi peaks during the first few hours of the photophase with males being protandrous. Females become sexually mature earlier than males and oviposit primarily in the photophase. Aphids parasitised in their early instars die before reproduction but those parasitised in later instars produce a limited number of progeny. Females prefer aphids of 3- to 5-d-old over the younger and older aphids for oviposition. Females ovipositing in 4- to 7-d-old aphids have more fitness gains in terms of progeny body size and egg load at emergence. Fertilised eggs are more likely deposited in large hosts and unfertilised eggs in small ones. Large individuals have greater longevity, large males father more progeny, and large females have higher fecundity, parasitism and greater ability in host searching. However, with increasing body size females gain more than males in longevity and fecundity but males gain more than females in the number of female progeny. Males can inseminate up to nine females and they carry about 82% effective sperm at emergence and replenish about 18% sperm during their adult life. Females adjust the oviposition and sex allocation strategies in response to increasing host density with higher number of aphids parasitised at higher host densities and lower proportion of female progeny produced at lower host densities. Males play an active role in mating behaviour. Males having mating experience, and being large or younger, respond to females more quickly and perform better courtships resulting in higher mating success. Males prefer larger and younger females for mating probably because the latter have greater reproductive potential. Males optimize the use of their sperm based on the availability of their sperm and the reproductive status (age) of females. The switchingoff of female receptivity of male mating attempt after the mating is a gradual process. Some females accept the second males within 1 minute since the termination of the first mating. The shorter mating period in the second mating suggests that females remate probably due to the gradual process of switching-off of female receptivity rather than the insufficient sperm transformation during the first mating. Males prolong their mating duration in male-biased operational sex ratio to reduce the probability of female remating.

Aphidius ervi Haliday is a cosmopolitan parasitoid species of several major aphid pests on economically important crops. Prior to this research, little information was available on its reproductive behaviour. Emergence of A. ervi peaks during the first few hours of the photophase with males being protandrous. Females become sexually mature earlier than males and oviposit primarily in the photophase. Aphids parasitised in their early instars die before reproduction but those parasitised in later instars produce a limited number of progeny. Females prefer aphids of 3- to 5-d-old over the younger and older aphids for oviposition. Females ovipositing in 4- to 7-d-old aphids have more fitness gains in terms of progeny body size and egg load at emergence. Fertilised eggs are more likely deposited in large hosts and unfertilised eggs in small ones. Large individuals have greater longevity, large males father more progeny, and large females have higher fecundity, parasitism and greater ability in host searching. However, with increasing body size females gain more than males in longevity and fecundity but males gain more than females in the number of female progeny. Males can inseminate up to nine females and they carry about 82% effective sperm at emergence and replenish about 18% sperm during their adult life. Females adjust the oviposition and sex allocation strategies in response to increasing host density with higher number of aphids parasitised at higher host densities and lower proportion of female progeny produced at lower host densities. Males play an active role in mating behaviour. Males having mating experience, and being large or younger, respond to females more quickly and perform better courtships resulting in higher mating success. Males prefer larger and younger females for mating probably because the latter have greater reproductive potential. Males optimize the use of their sperm based on the availability of their sperm and the reproductive status (age) of females. The switchingoff of female receptivity of male mating attempt after the mating is a gradual process. Some females accept the second males within 1 minute since the termination of the first mating. The shorter mating period in the second mating suggests that females remate probably due to the gradual process of switching-off of female receptivity rather than the insufficient sperm transformation during the first mating. Males prolong their mating duration in male-biased operational sex ratio to reduce the probability of female remating.

Uracanthus is a large group of longicorn beetles in the Australian Region. The larvae of this genus are borers of at least 31 genera of trees and parasitic plants, including some economically important crops such as citrus, litchi, peach, plum, and apricot. Several species are important pests of orchards. Adults visit flowers of various tree species and are attracted to the light. In this thesis, I undertook a thorough taxonomic revision, analysed the phylogeny using morphological and molecular characters, and appraised biogeographic distribution of the genus. In the taxonomic revision, I redefine the scope of the genus, describe and illustrate new and previously known species, and provide a key to all species. The revised Australian Uracanthus includes 39 species, eight of which are established as new to science: U. pseudogigas sp. nov., U. maculatus sp. nov., U. griseus sp. nov., U. bicoloratus sp. nov., U. perthensis sp. nov., U. punctulatus sp. nov., U. quadristriolatus sp. nov., and U. bistriolatus sp. nov. Six new synonyms are proposed (senior synonyms last): U. multilineatus McKeown with U. ventralis Lea, U. dentiapicalis McKeown with U. parvus Lea, U. marginellus Hope and U. inermis Lea (not Aurivillius) with U. bivittatus Newman, U. fuscostriatus McKeown with U. lateroalbus Lea, and U. daviumbus Gressitt with U. longicornis Lea. Dorsal views of all species are presented as photographs, terminalia of both sexes illustrated, and distributions mapped. Brief comments are also given on the biology of this genus. In the full morphological phylogenetic analyses of all 39 species, I use 55 informative characters and cladistic method to test the monophylies of Uracanthus and its species groups. My results show that the monophylies of the genus and seven species groups are confirmed. However, several species groups still need additional steps to become monophyletic and are currently considered paraphyletic. In the molecular phylogenetic studies, due to the situations beyond my control (difficulties of extracting DNA from some old species and prohibitions of extracting DNA from type specimens), I analyse only 21 species. I extract and amplify the cytochrome oxidase I (COI) region of the mtDNA from 21 species and perform a phylogenetic analysis using molecular characters. To make the molecular phylogeny comparable to the morphological phylogeny, I also cladistically analyse the phylogeny of these 21 species using morphological and combined morphological-molecular characters. A comparison of trees obtained from morphological, mtDNA and combined data shows that the relationships of several closely related taxa remain constant, for example, the sister relationships of U. gigas + pseudogigas, U. insignis + punctulatus, and U. acutus + loranthi. However, the placement of U. insignis and U. punctulatus on the phylogenetic trees varies from the most basal in the full morphological analysis to the highly derived in the combined and molecular analyses. Considering the amount of available data is more limited in the molecular analysis than in the morphological analysis, the molecular phylogeny presented in this study should be interpreted with caution. The Uracanthus fauna can be divided into five subregions: the Kosciuskan, Western and Eyrean in southern and central Australia, and the Torresian and Timorian in northern Australia. The fauna are richest with highest endemism in the Kosciuskan and Western. The Kosciuskan and Western are similar in faunal composition and closely related; the Eyrean has probably acted as a faunal exchange transit area between the Kosciuskan and Western, and the two northern Australian subregions have no endemic species. When the areas of endemism of each species are attached to the phylogenetic tree generated from the full morphological analysis, a clear picture of the distribution patterns of species groups in relation to phylogeny is obtained. It is suggested that the speciation and species radiation of Uracanthus may have occurred first in the Kosciuskan, then in the Western, and finally in the Eyrean, Torresian, and Timorian.