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Experiments with artificial diets demonstrated that black field cricket (Teleogryllus commodus (Walker)) and Lepidogryllus sp. were highly responsive to presence of lolines in their diet-quantities of diet consumed declined exponentially with increasing loline concentration. Amount consumed by black field cricket and Lepidogryllus sp. on diet containing 5,600 µg/g lolines was only 8 and 2% relative to those on loline-free diet, respectively. Additional experiments with Festulolium seeds demonstrated that both cricket species predated heavily on endophyte-free seed but largely avoided Epichloë uncinata-infected seed. By 12 h, black field cricket had destroyed 98.8% of endophyte-free but only 24.8% of E. uncinata-infected, loline-containing seed. By 36 h, Lepidogryllus sp. crickets had destroyed 40% of endophyte-free but had not fed on E. uncinata-infected, loline-containing seed. Glasshouse experiments demonstrated this aversion to lolines greatly reduces the damage potential of black field cricket in E. uncinata-infected Festulolium. When microswards were sown with E. uncinata-infected Festulolium, seedling numbers were reduced 25-26%, and yields 29-40%, by black field crickets relative to microswards sown without insect infestation. This contrasts with 70-78% reduction in seedling numbers and 67-80% reduction in yields in microswards sown to either endophyte-free Festulolium, endophyte-free perennial ryegrass, or Epichloë festucae var. lolii-infected Festulolium. Yields of mature E. uncinata-infected Festulolium plants were not adversely affected by black field crickets, irrespective of the presence of the endophyte-free standard Festulolium sown as a companion. In contrast, yields of endophyte-free Festulolium, endophyte-free perennial ryegrass, and E. festucae var. lolii-infected Festulolium plants were reduced by 56-61% by crickets.

The South American weevil Listronotus bonariensis (Kuschel) is an important pest of pastures in New Zealand. As a component of management strategies for this pest, the South American parasitoid Microctonus hyperodae Loan (Hymenoptera: Braconidae) was released in northern New Zealand during 1991 as a biological control agent. Over the subsequent 5-6 yr, the reproductive biology of M. hyperodae and its relationship to, and effects on, the reproductive phenology and fitness of L. bonariensis were studied at three sites. M. hyperodae was first recovered in the field in December 1991. Subsequently, the incidence of parasitism in L. bonariensis increased to seasonal maxima of 75-90%. There was variable synchrony between parasitoid generations and the two generations of its host, leading to marked seasonal variation in rates of parasitism and parasitoid abundance. Despite marked inter-year variation, abundance of host adult and egg populations declined in the presence of parasitoids. Parasitized host females had lower ovarian maturity scores, had lower egg loads, and exhibited less investment in wing muscle development than females that had escaped parasitism. There was almost complete elimination of egg maturation in parasitized females and these hosts contributed little to population recruitment. Rate of buildup and seasonal maxima in parasitism, frequency of superparasitism, adult abundances, and wing muscle development in adult L. bonariensis varied among the three sites in a manner that was only partially related to climate differences across the 1.83° gradient of latitude. Site effects were weak to absent in measures of reproductive condition in L. bonariensis females.

The value of biodiversity lies in its option value for the future, the greater the complement of contemporary biodiversity conserved today, the greater the possibilities for future biodiversity because of the diverse genetic resource needed to ensure continued evolution in a changing and uncertain world. From this perspective, biodiversity option value can be equated with richness in the different features expressed by species. An individual species of greater value is one contributing more novel features to a given subset. The feature diversity of species and communities is difficult to estimate directly, but can be predicted by the phylogenetic relationships among the species. The ‘Phylogenetic Diversity’ measure (PD) (Faith, 1992a) estimates the relative feature diversity of any nominated set of species by the sum of the lengths of all those branches spanned by the set. These branch lengths reflect patristic or path-length distances. This study first reviews and expands on some of the properties of PD, and develops simple modifications of the measure (δnPD and enPD) to enable capture of both the phylogenetic relatedness of species and their abundances in each sample. Then the application of PD, δnPD and enPD to a wide range of conservation and resource management issues is demonstrated using avian case studies. Supertree construction procedures (matrix representation using parsimony analysis; average consensus) were used to combine the extensive DNA-DNA hybridization tree of Sibley & Ahlquist (1990) with numerous, recently published phylogenetic reconstructions to derive a phylogenetic tree for the global avian fauna. Using this supertree as a systematic framework, the utility of PD was demonstrated in four case studies: (i) state of the environment reporting, with changes in avian faunas resulting from extinctions quantified as indicators of the state of biodiversity at Global, New Zealand and Waikato region scales, and changes in available habitat quantified as indicators of pressures on biodiversity in the Waikato region; (ii) setting priorities for threatened species management, with PD as a measure of option value integrated with information on survivorship expectations to develop a ranking among threatened New Zealand forest bird species; (iii) monitoring biotic response to management, with data from 5-minute counts used to analyse changes in forest bird communities under three management regimes in New Zealand; and (iv) selection of indicator species, with PD used to objectively identify subsets of species in the Global, New Zealand and Waikato avian faunas that comprise a high proportion of the option value in those faunas.

The South American curculionid Listronotus bonariensis (Kuschel) is an important pest of pastures in New Zealand. Population census data were gathered for L. bonariensis in northern New Zealand pastures during 1980–1983 in the absence of parasitism and again in 1991–1996 after the introduction and establishment of the braconid parasitoid Microctonus hyperodae Loan as a biological control agent. M. hyperodae achieved high rates of parasitism, with 75–90% of overwintering L. bonariensis parasitized within 3 yr of the parasitoid establishing at a site. Multistratum analysis of variance (ANOVA), with allowance for variation in host plant resource (numbers of Neotyphodium-free grass tillers), indicated reduction in the abundance of L. bonariensis life stages in the early part of life cycle. Although providing evidence for suppression of L. bonariensis, these analyses indicated the regulatory role of M. hyperodae was weak because L. bonariensis populations continued to exhibit marked intergenerational ...

Laboratory host specificity of 2 biological control agents, already introduced in New Zealand, was compared with actual field parasitism. The parasitoids were Microctonus aethiopoides Loan and Microctonus hyperodae Loan, braconids imported to control the curculionid forage pests Sitona discoideus Gyllenhal and Listronotus bonariensis (Kuschel), respectively. The nontarget weevil species tested included native, introduced, and beneficial species. M. aethiopoides oviposited in 11 of the 12 species to which it was exposed and successfully parasitized 9 species. M. hyperodae oviposited in 5 of the 11 species to which it was exposed and developed successfully in 4 species. Higher percentage parasitism was recorded with M. aethiopoides than with M. hyperodae . Field collections of weevils from Otago, Canterbury, and Waikato indicated that 10 New Zealand native species and 3 other nontarget species, including the weed biological control agent Rhinocyllus conicus (Froehlich), were parasitized by M. aethiopoides . M. hyperodae has been found parasitizing 1 native species, as well as Sitona lepidus Gyllenhal, which was accidentally introduced to New Zealand recently. In nontarget species, parasitism levels in the field of >70% have been recorded for M. aethiopoides and

Laboratory experiments were done to examine the effect of ryegrass infection by the endophytic fungus Acremonium lolii Latch, Christensen & Samuels (Ascomycetes: Clavicipitaceae) on Microctonus hyperodae Loan, a parasitoid of Listronotus bonariensis (Kuschel). Infection of ryegrass did not influence the rate of parasitism in weevils confined with naive parasitoids to individual plants and to ryegrass swards in small plots. In contrast, M. hyperodae with prior experience of hosts feeding on endophyte infected grass subsequently were more efficient in parasitizing hosts on this diet. Feeding on individual plants and small plot swards by weevil for 3–4 d increased subsequent parasitoid attack rate.

The flight behavior of Listronotus bonariensis (Kuschel) in Waikato (New Zealand) pastures was studied by recording catches on aerial sticky traps and sampling ground populations; this was supported by dissection studies and laboratory experimentation. All flight activity in the field occurred between 25 August and 5 May. Flight phenology and intensity varied greatly between localities and years. Intensity was generally low, although occasional mass flights were observed. Sampled ground populations indicated that only a proportion of the weevils exhibited development of flight musculature and hence flight capability: the proportion of these “flight capable” weevils varied greatly from generation to generation. Field sampling and laboratory experimentation indicated partitioning of reproductive and dispersive effort among individuals in the population. Following emergence, some weevils became reproductive and others developed flight musculature before ovarian development and dispersal. The proportion of weevils in the latter category was highest in the field following peak emergence and was shown by laboratory experimentation to be increased by weevil crowding, particularly on unfavorable host plants. The laboratory experiments also indicated that alleviation of crowding resulted in degeneration of flight musculature and resumption of reproductive activity. Field sampling indicated overwintering in the pastures (summer breeding grounds) and no migration to adjacent potential hibernation sites. These results are discussed in relation to the climate of the Waikato and the dynamics of the populations.