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The threat of Bt resistance in Helicoverpa armigera (Hubner 1808) and H. punctigera (Wallengren 1860) (Heliothinae) is a major impediment to the sustainability of transgenic (Bt) cotton crops in Australia. A resistance management plan has, therefore, been instigated that in part requires farmers to sow their Bt cotton within specified dates to limit the number of generations of Helicoverpa spp. that are exposed to Bt toxins during the growing season. This study evaluated this strategy by utilising industry-wide databases of planting dates and other cropping/pest management events throughout 11 growing seasons. The analysis included model predictions of when Helicoverpa is likely to enter winter (pupal) diapause and emerge as moths in spring, and the long-term pheromone trapping records of moths. In New South Wales and southern Queensland (Qld), most first-generation moths were caught at the same time, or before, cotton was planted (mostly in October). This generation was, therefore, unlikely to have been exposed significantly to Bt toxins as feeding larvae in spring, but some individuals (especially H. armigera) may have been exposed to Bt prior to pupating in the previous autumn. Three subsequent generations, which could have been exposed to Bt during summer–autumn, were recognisable in trap catches before moths became very rare in early April. By then, the majority of Helicoverpa had entered winter diapause as pupae and cotton harvest was well underway. We conclude that the current planting window (pre-mid-November in these regions) achieves little in limiting the exposure of Helicoverpa to Bt. However, insufficient is known of the population dynamics of Helicoverpa in central Qld to be as definitive about the need for planting windows there. Importantly, Helicoverpa are active all year round in central Qld and cotton can be grown over a longer period, thus increasing the risks of greater exposure to Bt.

The Heliothinae comprise some of the world's most injurious agricultural pests. This study reanalyses a subsample of the Heliothis group to determine the monophyly of Chloridea (Heliothis virescens and H. subflexa). Two nuclear gene regions, elongation factor-1α (EF-1α; 1240 bp) and dopa decarboylase (DDC; 687 bp), and the barcoding region of mitochondrial cytochrome oxidase I (COI; 708 bp) were used in this analysis for a total of 2635 bp and a morphological dataset of 20 characters and 62 character states. Sixteen species representing five genera plus two outgroup species were used in the analysis. Analyses used were Maximum Parsimony (MP), Maximum Likelihood (ML) and Bayesian Inference (BI). The revised status for the monophyletic genus Chloridea Duncan and (Westwood) was supported by a very strong bootstrap support (BP = 98–100). Larval host-plant usage is discussed within the Heliothis clade. Polyphagy is most likely the ancestral condition with a host shift to monophagy and oligophagy. Based on known larval hosts, Heliocheilus is oligophagous on Poaceae. Traits of host plant use in Helicoverpa and Chloridea where both polyphagy and oligophagy occur in closely related species are discussed.

A broad molecular systematic survey of Noctuidae was undertaken to test recent hypotheses on the problematic definitions and relationships of the subfamilies, with special emphasis on the ‘trifines.’ An initial hypothesis of noctuid classification to the subtribal level was synthesized from recent reviews, and then sampled as broadly as possible. Concatenated sequences for the nuclear genes elongation factor-1α (EF-1α; 1200 bp) and dopa decarboxylase (DDC; 700–1100 bp) were analysed for a total of 146 exemplar species, twice that of a previous study. Trees were estimated using likelihood, distance, and both equally weighted and ‘six-parameter’ parsimony. Of the 144 possible nodes, bootstrap support (BP) was ≥ 50% for ∼80, and ≥ 80% for ∼60. There was very strong support (BP ≥ 90%) for an ‘L.A.Q.’ clade encompassing nearly all quadrifine noctuids plus Arctiidae and Lymantriidae, decisively rendering Noctuidae paraphyletic. We present a new classification for Noctuoidea in which Noctuidae sensu stricto is restricted to trifines; most quadrifine subfamilies are raised to full families. Within the ‘L.A.Q.’ clade, Aganainae and Herminiinae were strongly grouped, but other relationships were weakly supported, probably due to limited taxon sampling. Nolidae and Euteliinae + Stictopterinae are generally grouped with the ‘L.A.Q.’ clade, but with weak support. All analyses favour the broadest definitions proposed for the trifine clade (our Noctuidae sensu stricto) although support is not strong, except that the exemplar of Eustrotiinae: Eublemmini is placed securely in the ‘L.A.Q.’ clade. Numerous recent proposals for dismantling and recombining the ‘Hampsonian’ traditional trifine subfamilies are strongly supported, most notably a broadly defined ‘true cutworm’ clade (Noctuinae s.l.), encompassing the greater part of the traditional subfamilies Amphipyrinae, Cuculliinae, Hadeninae and Noctuinae s.s. (BP ≥ 95%). Within this clade there is strong support for Apameini s.s.+ Xylenini s.l. and for Noctuinae s.s. and divisions thereof, but little support for monophyly or subdivision of Hadeninae. Noctuinae s.l. invariably are allied with Heliothinae, scattered remnants of the traditional Amphipyrinae, and several smaller groups in a broader ‘pest clade’, albeit with weak support. Relationships among the remaining ‘lower’ trifines are not strongly resolved. Mapping of a preliminary synopsis of species diversities, host use patterns and latitudinal distributions on the phylogeny suggests that the diversification of trifines may have been promoted, to a degree unique among Macrolepidoptera, by the Tertiary expansion of seasonal, open habitats and their associated herbaceous floras.

The glomeruli of the antennal lobes in insects reflect the organization of the olfactory system, which is important for species-specific behaviors in response to insect- and plant-produced odorants. We studied the antennal lobes of the polyphagous moth Helicoverpa armigera and the oligophagous H. assulta (Heliothinae; Lepidoptera; Noctuidae) in order to see whether there are any anatomical differences that might elucidate how information about odorants is analyzed. Three-dimensional models of the antennal lobes were made, based on synaptic antibody staining combined with confocal laser scanning microscopy. These showed 65 glomeruli in each sex of H. armigera and 66 glomeruli in females of H. assulta. Sixty-two of the glomeruli were identified in both sexes and species and were given the same numbers. The sex-specific glomeruli included three macroglomerular units in H. armigera males, as well as three and four female-specific glomeruli in H. armigera and H. assulta, respectively. The species specificity of H. assulta females also appeared by the particular large size of two ordinary glomeruli. The accumulating knowledge on how biologically relevant information is encoded in receptor and antennal lobe neurons in heliothines makes these moths particularly interesting for studying the functional organization of the glomeruli. The anatomical atlases of the antennal lobes, as presented here, are prerequisites for identifying glomeruli ascribed to particular functions across sexes and species.

Helicoverpa gelotopoeon Dyar is a very important pest of economic importance on cotton in Argentina. Analysis of female pheromone gland extracts prepared from 1- to 2-day-old virgin female moths demonstrated the presence of a 1 : 0.84 blend of hexadecanal (16:Ald) and (Z)-9-hexadecenal (Z9-16:Ald), with trace quantities of tetradecanal in some samples, 2.4% of 16:Ald. The average quantity of Z9-16:Ald extracted per female was estimated to be 33 ng, with a range of 18.9-46.4 ng per female when collected 2-3 h into the scotophase. In field trials conducted in both cotton and tomato crops in Santiago del Estero, Argentina 1 : 1 blends of 16:Ald and Z9-16:Ald caught significantly more male H. gelotopoeon than Z9-16:Ald alone, although there was no significant difference between blends containing between a 0.2 : 1 and 2 : 1 ratio of 16:Ald and Z9-16: Ald. There was no analytical evidence for the presence of (Z)-11-hexadecenal (Z11-16:Ald) in pheromone gland extracts, although this compound has been identified in all female sex pheromones of Heliothinae to date. In field trials, the addition of Z11-16:Ald at the 1% level to either a 1 : 1 blend of 16:Ald and 29-16:Ald or Z9-16:Ald alone significantly reduced the catch of male H. gelotopoeon. Sympatric Heliothis virescens were not caught in any of the blends tested for H. gelotopoeon, but were caught in low numbers in traps baited with a 4 : 100 blend of (Z)-9-tetradecenal and (Z)-11-hexadecenal.

Potential host plants of the polyphagous lepidopteran Helicoverpa punctigera (Wallengren) were surveyed in two ways. A broad survey, conducted in southern Queensland and northern New South Wales, indicated that H. punctigera larvae were present on relatively few plant species. A detailed survey of host plant use in a non‐cropping area in which H. punctigera was numerous demonstrated restricted host plant use by this species. The density of H. punctigera on its principal host in the area, the indigenous daisy Ixiolaena brevicompta F. Muell., was much higher (as measured per unit of time searched) than on other plant species available. Also, I. brevicompta was used regularly by H. punctigera after rainfall events. Ixiolaena brevicompta represents a new host record and on the basis of the pattern of its use by H. punctigera should be considered a ‘primary host plant’ of this noctuid. In cropping areas sampled, usually more than one plant species hosted H. punctigera regularly and in large numbers. Usually a crop species was included (e.g. cotton and chick pea). Alternative hosts in cropping areas were Sonchus oleraceus L. (sowthistle) and possibly the native legume Sesbania cannabina (Retz.) Poiret. Our results imply that the polyphagy of H. punctigera is probably not as extensive as previously claimed. The criteria for inclusion of a plant species as a primary host for H. punctigera need to include the regularity of use of that species and the relative abundance of eggs and larvae on it. We suggest that an understanding of the host‐searching mechanism of this species will be best achieved through study of the interaction of H. punctigera with its indigenous primary hosts. The surveys also yielded information on host plants of two other heliothine noctuids, H. armigera (Hubner) and Australothis rubrescens (Walker), and this is also presented. Copyright