Gimme H. Walter's research while affiliated with The University of Queensland and other places

Publications (256)

Article
Two stingless bee species, Tetragonula carbonaria and Tetragonula hockingsi , engage in extreme inter-colony fights, both within and between species. Inter species fights can result in one species taking over the nest of the other. Following successful takeovers, brood from the previous colony could be retained and become workers, but this has yet...
Article
Why are most herbivorous insects so specialized? How do generalists and specialists differ ecologically? And what sensory and cognitive processes determine which host species an insect recognizes and uses? We review sensory cues involved at different stages of interaction with host plants and outline a unified scheme of insect–host interaction mech...
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A clear understanding of a species’ diet is crucial in understanding its spatio-temporal dynamics, and is, therefore, pertinent to conservation considerations. The diet of the Grey Falcon (Falco hypoleucos), a rare and threatened predator endemic to the Australian arid and semi-arid zone, is subject to diverging assertions; therefore, we studied it...
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Herbicides are commonly deployed as the front-line treatment to control infestations of weeds in native ecosystems and among crop plants in agriculture. However, the prevalence of herbicide resistance in many species is a major global challenge. The specificity and effectiveness of herbicides acting on diverse weed species are tightly linked to tar...
Article
Acacia auriculiformis is a native Australian tree that has now become a category 1 invasive weed in Florida, USA. Previous research has identified Macrobathra moths as potential biological control agents for this weed, but little is known about the genetic diversity and structuring of these moths. In this study, we compared the genetic structure of...
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Rhyzopertha dominica and Tribolium castaneum are key pests of stored grains globally. These two species often occur together in infestations, and are seldom found outside the agricultural environment. Understanding the movement of these beetle pests is crucial for the development of management strategies, in particular to prevent the spread of phos...
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Biological control is often the most cost effective and environmentally sound method of managing widespread environmental weeds. Earlier detection of cryptic species and improved understanding of host-herbivore associations during the initial screening for effective natural enemies should further boost success rates. We formalise a framework for im...
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Premise: Although maintaining the appropriate mid-day timing of the diel thermogenic events of cones of the dioecious cycads Macrozamia lucida and M. macleayi is central to the survival of both plant and pollinator in this obligate pollination mutualism, the nature of the underlying mechanism remains obscure. We investigated whether it is under ci...
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Rapid learning in the young of most endothermic animals can be expected to be favoured by natural selection because early independence reduces the period of vulnerability. Cases of comparatively slow juvenile development continue, therefore, to attract scientific attention. In most species of birds, including raptors, the young depend on their pare...
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Host plant relationships of Australian native and invasive whitefly species in the Bemisia tabaci species complex, namely AUSI and AUSII and Bemisia argentifolii (also called B. tabaci Middle East-Asia Minor 1 (MEAM1), were investigated with three approaches: ecologically in the field with surveys, experimentally in the laboratory, and using popula...
Article
Endothermic animals that live permanently in hot deserts must avoid harmful hyperthermia when their body temperature increases from heat gained through external and internal sources. This is true particularly for endotherms that are exclusively diurnal. We investigated the Grey Falcon (Falco hypoleucos), a predatory Australian endemic restricted to...
Article
Crocidolomia pavonana F. (Lepidoptera: Crambidae) is a major pest of Brassica crops. No effective natural enemies of C. pavonana were known until the discovery of a population of the egg parasitoid Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae) that was effective in suppressing the pest in Samoa. Records of significantly lower parasit...
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Detecting the number of invasions is crucial to understanding the process of invasion and perhaps the success of some invasive pest species. Detecting multiple invasions can be difficult using partial mitochondrial COI, however, due to lack of variation. To examine the post-invasion history of Bemisia argentifolii (also called B. tabaci Middle East...
Article
Understanding the thermal dynamics of host-parasitoid interactions is crucial to predicting how biological control of pest insects by parasitoids might be affected by geographic location and climate change. We compared performance traits of Plutella xylostella (Lepidoptera: Plutellidae) and its solitary endo-larval parasitoid Diadegma semiclausum (...
Article
The Grey Falcon (Falco hypoleucos) is a rare Australian endemic bird of prey confined for its entire life to the continent's hot arid and semi-arid zone. The prevention of hyperthermia is therefore a crucial challenge. Birds, in general, rely on a dynamic balance between physiological mechanisms and the behaviours that augment them. Effective heat...
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Cycad cone thermogenesis and its associated volatiles are intimately involved in mediating the behavior of their obligate specialist pollinators. In eastern Australia, thrips in the Cycadothrips chadwicki species complex are the sole pollinators of many Macrozamia cycads. Further, they feed and reproduce entirely in the pollen cones. M. miquelii, f...
Article
Acacia auriculiformis is a native Australian tree that has developed into a damaging environmental weed in Florida, USA. We conducted field surveys to collect insect herbivores from A. auriculiformis and three closely related allopatric congeners (A. crassa, A. leiocalyx, and A. concurrens) across the native distribution of each plant species. We c...
Article
Studies of insect movement are hampered by the small size of insects and the associated difficulty in tracking them in the environment. We tested the potential of quantum dots (QDs) to mark large numbers of insects very quickly. Our results demonstrate that green CdTe (cadmium tellurium) QDs were effective markers in the laboratory and can be appli...
Article
Prickly acacia (Vachellia nilotica) has been the target of biological control programmes in Australia for over three decades, with little success. Control efforts may have been hindered by poor characterisation of the plants in Australia, and the ambiguous taxonomy of the species. Nine subspecies of this weed have been described, with only one subs...
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Generalist insect herbivores may be recorded from a great variety of host plants. Under natural conditions, however, they are almost invariably associated with a few primary host species on which most of the juveniles develop. We experimentally investigated the interaction of the generalist moth Helicoverpa punctigera Wallengren (Lepidoptera: Noctu...
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1. Host recognition and movement among plant species is widely studied in adult insects. These behaviours are rarely considered in juveniles despite evidence that they also move between plants. 2. This study investigated what may influence caterpillars of a generalist moth Helicoverpa punctigera to move among individual plants and whether caterpil...
Article
Aim: Understanding the genetic structure of plants in their native range is crucial when reconstructing the invasion history of weeds. This information allows researchers to pinpoint the provenance of invasive plants and to test the importance of genetic admixture in facilitating invasion success. We assessed genetic structuring across the native r...
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(1) The distribution of organisms that inhabit patchy systems is dictated by their ability to move between patches, and the suitability of environmental conditions at patches to which they disperse. Understanding whether the species involved are identical to one another in their environmental requirements and their responses to variance in their en...
Article
The ecology of Tribolium castaneum (Herbst) outside of grain storage facilities is poorly known. However, high densities of T. castaneum adults are known to infest stored cotton seeds (Gossypium hirsutum (L.)) in Queensland, Australia, despite the absence of stored food products in the immediate vicinity. Previous studies suggest that the beetles a...
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Introduction: Brown planthoppers (Nilaparvata lugens) are the most serious insect pests of rice, one of the world's most important staple crops. They reproduce year-round in the tropical parts of their distribution, but cannot overwinter in the temperate areas where they occur, and invade seasonally from elsewhere. Decades of research have not rev...
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Generalist insect herbivores feed mainly on one or more primary host species, but unlike specialists they also accept numerous secondary hosts. This raises the question of how generalists retain a broad host range yet allocate most of their eggs to primary hosts. We considered three possible explanations. 1) Threshold: secondary hosts are accepted...
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The presence of distinct evolutionary lineages within herbivorous pest insect taxa requires close attention. Scientific understanding, biosecurity planning and practice, and pest management decision making each suffer when such situations remain poorly understood. The pest bug Nezara viridula Linnaeus has been recorded from numerous host plants and...
Article
Most cycads have intimate associations with their insect pollinators that parallel those of well‐known flowering plants, such as sexually deceptive orchids and the male wasps and bees they deceive. Despite this, the mistaken belief that cycads are mostly wind‐pollinated is still commonly expressed. Perhaps as a consequence, cycad–pollinator systems...
Article
Many plant bugs (Miridae) are generalist herbivores that feed on multiple host species. The reasons these bugs move across hosts and the behavioural mechanisms responsible for their retention at specific hosts remain elusive. Green mirids ( Creontiades dilutus ) are endemic to Australia. These insects are important pests of cotton ( Gossypium hirsu...
Article
Resistance in pest insects to the grain fumigant phosphine (PH 3) poses a threat to trade and food security. The possible pleiotropic effects of PH 3 resistance on development and reproduction were investigated in the red flour beetle, Tribolium castaneum (Herbst), by introgressing two genes known to be major contributors to strong resistance (tc_r...
Preprint
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Discrepancies in mitochondrial and nuclear genetic data are often interpreted as evidence of hybridisation. We re-examined reports of hybridisation in three cryptic stingless bee species in the genus Tetragonula in South East Queensland, Australia (T. carbonaria, T. davenporti, and T. hockingsi). Previous studies on this group using microsatellites...
Preprint
Full-text available
Brown planthoppers ( Nilaparvata lugens ) are the most serious insect pests of rice, one of the worlds most important staple crops. They reproduce year-round in the tropical parts of their distribution, but cannot overwinter in the temperate areas where they occur, and invade seasonally from elsewhere. Decades of research has not revealed their sou...
Article
The Grey Falcon Falco hypoleucos is one of the world’s rarest raptors, with an estimated population size of fewer than 1,000 individuals. Our knowledge of threats posed to the Grey Falcon remains scant. Understanding the genetic variation in this species would help to assess its conservation status more realistically and its prospects for survival...
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Generalist insect herbivores, those recorded as using numerous hosts (tens or even hundreds of species), are not well understood ecologically. We suggest ways to investigate the ecology of these species beyond the practice of accumulating host records. We present reasons why multiple host use by herbivorous insects needs to be quantified in the fie...
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The genus Vachellia Wight & Arn. has a pantropical distribution, with species being distributed through Africa, the Americas, Asia and Australia. The relationships among the lineages from Africa and America are well understood, but the phylogenetic placement and evolutionary origins of the Australian species of Vachellia are not known. We, therefor...
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An understanding of how sublethal exposure to phosphine affects an organism’s respiration is important for predicting its effects on activities depending on a reliable energy source including movement. After treatment with the appropriate sublethal doses of phosphine (LC10), both resistant and susceptible Tribolium castaneum beetles suffered reduct...
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1. Introduction. 2. The Specific-mate Recognition System (SMRS). 3. The Genetic Change As sociated with Speciation.
Article
The Grey Falcon (Falco hypoleucos) is a desert-living species restricted to the dry centre of Australia. These falcons have a number of unique life-history adaptations that may be crucial for their survival in this harsh environment, but these may, conversely, confine them to these arid regions. In this study we investigated what Grey Falcon feathe...
Article
Managing agricultural pests that use multiple host plant species is a challenge when individuals move between host plants in natural vegetation and agricultural environments. The green mirid (Creontiades dilutus) Stål (Hemiptera: Miridae) is endemic to Australia and routinely invades cotton from local uncultivated vegetation, but may also originate...
Article
Bemisia tabaci (Gennadius) represents a relatively large cryptic species complex. Australia has at least two native populations of B. tabaci sensu lato and these were first found on different host plants in different parts of Australia. The species status of these populations has not been resolved, although their mitochondrial sequences differ by 3...
Article
1. Worldwide, the excessive use of insecticides has resulted in field‐evolved insecticide‐resistant populations of diamondback moth (DBM), Plutella xylostella. A deltamethrin‐resistant DBM population from the field was divided into two subpopulations in the laboratory. One population (S‐strain) was maintained with no further exposure to insecticide...
Article
The rice weevil, Sitophilus oryzae, is a serious global pest of stored grains. Fumigation with phosphine gas is the primary control method for S. oryzae, but the indiscriminate and prolonged use of phosphine gas has led to the development of heritable resistance. Developing and implementing an effective phosphine resistance management strategy for...
Article
Australia’s endemic Grey Falcon is an iconic but elusive bird of the arid interior. Whilst reviews of its ecology and status are more than 25 years old, new targeted studies include a population size estimate that is considerably lower (<1,000 individuals) than the one previously advanced (<5,000 individuals). According to this revised estimate, th...
Article
The reasons for Tribolium castaneum undertaking dispersal flight in the field are poorly known. The research reported here was designed to test, in the field, the predictions generated from our previous laboratory study about the dispersal flight of T. castaneum beetles. The results of that laboratory study suggested that younger beetles with large...
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Cylas formicarius F. and Euscepes batatae Waterhouse are the most damaging sweet potato insect pests globally. Both weevils are thought to have invaded the Pacific alongside the movement of sweet potato (Ipomoea batatas (L.) Lam. Convolvulaceae), with C. formicarius having originated in India and E. batatae in Central or South America. Here we comp...
Article
The larval females of Coccophagus sp. nr gurneyi Compere are primary parasitoids of lantana mealybugs, whereas males develop hyperparasitically through other parasitoids (never their own females), so the species is alloparasitic. Males are seldom even reared from lantana mealybugs (<0.3%, n = 4,212), and have not yet been reared from any other host...
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Background: The rice stem borer, Chilo suppressalis, is a serious pest of rice, but also damages an aquatic vegetable, water oats (Zizania latifolia Turcz.). The time at which mating occurs is different between populations of rice stem borer associated with rice and those associated with water-oats, which suggests that undetected cryptic species m...
Article
Biological control is considered the best management option against the aquatic weed Hydrilla verticillata, one of the most damaging invasive plants in the United States. The search for natural enemies is ongoing. Larval flies from two families (Ephydridae and Chironomidae) were collected feeding on H. verticillata during recent surveys across Chin...
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The flight of Tribolium castaneum (Herbst) in leaving infestations and establishing new infestations, independent of human mediation, has received little experimental attention. This study focuses on the patterns of flight of T. castaneum beetles in the nearby vicinity of an environment that provides all requirements—that is, an environment from wh...
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Rhyzopertha dominica and Tribolium castaneum are key pests of stored grains globally. Fumigation with phosphine gas is the primary control method for these beetles, so the development of phosphine resistant populations threatens the continued use of this fumigant. Developing effective strategies to manage the spread of phosphine resistance requires...
Article
Lygodium microphyllum is considered one of the most damaging environmental weeds in Florida. Despite substantial efforts to control this fern, it continues to spread rapidly through the Greater Everglades ecosystem and other regions of Florida. Biological control is considered a critical component of the management strategy to control this weed, an...
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Finding plants for their eggs is the only parental care shown by many winged insects. Hatched juveniles often feed on one individual plant until gaining the power of flight as adults. Females are therefore predicted to lay more eggs on plants supporting high offspring survival. Many experiments comparing egg-laying and offspring survival across pla...
Article
Cubane was recently validated as a phenyl ring (bio)isostere, but highly strained caged carbocyclic systems lack π character, which is often critical for mediating key biological interactions. This electronic property restriction associated with cubane has been addressed herein with cyclooctatetraene (COT), using known pharmaceutical and agrochemic...
Article
The flight behaviour of Tribolium castaneum was studied in the laboratory by characterising the physiological factors related to flight initiation in these small but long-lived beetles. We investigated the flight propensity of T. castaneum at two different ages at the same time: old beetles (∼12 weeks post-emergence) and young ones (∼2 weeks post-e...
Article
Green mirids, Creontiades dilutus (Stål) (Hemiptera, Miridae), are primary pests of cotton (Gossypium hirsutum) (Malvaceae) in eastern Australia. Severe infestations delay crop development and reduce yield through boll drop (fruit loss). Most cotton farmers employ crop consultants to monitor mirids and recommend pest management options. Effective p...
Article
Pharmaceutical and agrochemical discovery programs are under considerable pressure to meet increasing global demand and thus require constant innovation. Classical hydrocarbon scaffolds have long assisted in bringing new molecules to the market place, but an obvious omission is that of the Platonic solid cubane. Eaton, however, suggested that this...
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The Old World climbing fern, Lygodium microphyllum, is a rapidly spreading environmental weed in Florida, United States. We reconstructed the complete chloroplast genome of L. microphyllum from Illumina whole-genome shotgun sequencing, and investigate the phylogenetic placement of this species within the Leptosporangiate ferns. The chloroplast geno...
Article
An analysis of the population genetics of Cryptolestes ferrugineus, across all major regions in Australia where grain is grown and stored in bulk, provides an initial step in investigating the movement of these insects and implications for the spread of phosphine resistance. Microsatellite data revealed two levels of genetic structure. Across Austr...
Article
• Parasitoid wasps of the Polysphincta genus‐group are highly specialised on their spider hosts, and most of them are known to manipulate their hosts into building a special web in which the parasitoid pupates. Trophic niche and the plasticity of host use were investigated in the koinobiont parasitoid Zatypota kauros Gauld from Queensland, Australi...
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Common blossom thrips, Frankliniella schultzei Trybom (Thysanoptera: Thripidae), feed on pollen and flower tissues. They use multiple host species, but are regularly found in abundance on only some, with the red-flowered Malvaviscus arboreus the primary host in South-East Queensland. Flower-feeding insects commonly use plant odours and colour to re...
Article
Cycads in the Zamiaceae are well known for their host-specific insect pollination mutualisms. Pollination of Cycas in the sister family Cycadaceae is less well-documented, with beetle pollination possibly coexisting with a limited potential for wind pollination, a hypothesis we tested for C. ophiolitica in Central Queensland, Australia. Cones were...
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Resistance to the fumigant phosphine has been demonstrated to impact on the dispersal abilities of the stored product pest Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). A series of behavioural bioassays were conducted in a wind tunnel to further investigate whether the fitness consequences of phosphine resistance on flight propensity an...
Article
Assessing the genetic diversity and structuring of potential biological control agents in their native range can be a vital step in developing efficient biological control programs. These assessments, however, are not routinely conducted prior to release of agents. Assessments of these variables after releases have been made may also provide valuab...
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Sonchus oleraceus, common sowthistle, is an asteraceous weed in Australian agricultural systems and has recently developed resistance to glyphosate. We present the complete chloroplast sequence of S. oleracueus reconstructed from Illumina whole genome shotgun sequencing. This is the first complete chloroplast genome available for the genus Sonchus....