Bactrocera Tryoni Research Articles

Divergent Heat Stress Responses in Bactrocera tryoni and Ceratitis capitata.

Invasive Tephritid fruit flies rank among the most destructive agricultural and horticultural pests worldwide. Heat treatment is commonly employed as a post-harvest method to exterminate fruit flies in fruits or vegetables. These pest species exhibit distinct tolerance to heat treatments, suggesting that the molecular pathways affected by heat may differ among species. In this study, the Queensland fruit fly (Qfly), Bactrocera tryoni, was utilised as a model investigate its molecular response to heat stress through heat bioassays. RNA samples from flies before and after heat treatment were extracted and sequenced to identify genes with significant changes in expression. These findings were compared to another serious Tephritid fruit fly species, the Mediterranean fruit fly (Medfly), Ceratitis capitata, under similar heat treatment conditions. The analysis reveals only three common genes: heat shock protein 70 (HSP70), HSP68, and 14-3-3 zeta protein. However, despite these shared genes, their expression patterns differ between Qfly and Medfly. This suggests that these genes might play different roles in the heat responses of each species and could be regulated differently. This study presents the first evidence of differing molecular responses to heat between Qfly and Medfly, potentially linked to their varied origins, habitats, and genetic backgrounds. These findings offer new insights into Tephritid fruit fly responses to heat at the molecular level, which may help refine post-harvest strategies to control these pests in the future.

Testing the potential of entomopathogenic nematodes in attract‐and‐kill and autodissemination approaches in the control of Queensland fruit fly, Bactrocera tryoni

Testing the potential of entomopathogenic nematodes in attract‐and‐kill and autodissemination approaches in the control of <scp>Queensland</scp> fruit fly, <i>Bactrocera tryoni</i>

Tracking and modeling the movement of Queensland fruit flies, Bactrocera tryoni, using harmonic radar in papaya fields

Determining movement parameters for pest insects such as tephritid fruit flies is critical to developing models which can be used to increase the effectiveness of surveillance and control strategies. In this study, harmonic radar was used to track wild-caught male Queensland fruit flies (Qflies), Bactrocera tryoni, in papaya fields. Experiment 1 continuously tracked single flies which were prodded to induce movement. Qfly movements from this experiment showed greater mean squared displacement than predicted by both a simple random walk (RW) or a correlated random walk (CRW) model, suggesting that movement parameters derived from the entire data set do not adequately describe the movement of individual Qfly at all spatial scales or for all behavioral states. This conclusion is supported by both fractal and hidden Markov model (HMM) analysis. Lower fractal dimensions (straighter movement paths) were observed at larger spatial scales (> 2.5 m) suggesting that Qflies have qualitatively distinct movement at different scales. Further, a two-state HMM fit the observed movement data better than the CRW or RW models. Experiment 2 identified individual landing locations, twice a day, for groups of released Qflies, demonstrating that flies could be tracked over longer periods of time.

Predicting species invasiveness with genomic data: Is genomic offset related to establishment probability?

Predicting the risk of establishment and spread of populations outside their native range represents a major challenge in evolutionary biology. Various methods have recently been developed to estimate population (mal)adaptation to a new environment with genomic data via so-called Genomic Offset (GO) statistics. These approaches are particularly promising for studying invasive species but have still rarely been used in this context. Here, we evaluated the relationship between GO and the establishment probability of a population in a new environment using both in silico and empirical data. First, we designed invasion simulations to evaluate the ability to predict establishment probability of two GO computation methods (Geometric GO and Gradient Forest) under several conditions. Additionally, we aimed to evaluate the interpretability of absolute Geometric GO values, which theoretically represent the adaptive genetic distance between populations from distinct environments. Second, utilizing public empirical data from the crop pest species Bactrocera tryoni, a fruit fly native from Northern Australia, we computed GO between "source" populations and a diverse range of locations within invaded areas. This practical application of GO within the context of a biological invasion underscores its potential in providing insights and guiding recommendations for future invasion risk assessment. Overall, our results suggest that GO statistics represent good predictors of the establishment probability and may thus inform invasion risk, although the influence of several factors on prediction performance (e.g., propagule pressure or admixture) will need further investigation.

Differential pheromone profile as a contributor to premating isolation between two sympatric sibling fruit fly species.

Bactrocera tryoni (Froggatt) and Bactrocera neohumeralis (Hardy) are sibling fruit fly species that are sympatric over much of their ranges. Premating isolation of these close relatives is thought to be maintained in part by allochrony-mating activity in B. tryoni peaks at dusk, whereas in B. neohumeralis, it peaks earlier in the day. To ascertain whether differences in pheromone composition may also contribute to premating isolation between them, this study used solid-phase microextraction and gas chromatography-mass spectrometry to characterize the rectal gland volatiles of a recently collected and a more domesticated strain of each species. These glands are typical production sites and reservoirs of pheromones in bactrocerans. A total of 120 peaks were detected and 50 were identified. Differences were found in the composition of the rectal gland emissions between the sexes, species, and recently collected versus domesticated strains of each species. The compositional variation included several presence/absence and many quantitative differences. Species and strain differences in males included several relatively small alcohols, esters, and aliphatic amides. Species and strain differences in females also included some of the amides but additionally involved many fatty acid esters and 3 spiroacetals. While the strain differences indicate there is also heritable variation in rectal gland emissions within each species, the species differences imply that compositional differences in pheromones emitted from rectal glands could contribute to the premating isolation between B. tryoni and B. neohumeralis. The changes during domestication could also have significant implications for the efficacy of Sterile Insect Technique control programs.

Assessment of the efficacy of Piper methysticum (Micrembryeae: Piperaceae) as a bioinsecticide, and/or spinosad combined with attractive plant volatiles for a novel lure and kill strategy against Bactrocera tryoni (Diptera: Tephritidae) in laboratory.

The Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), is a crop pest of global economic importance because of its wide range of hosts and its invasiveness capacities. To develop a novel integrated and sustainable crop protection, we have investigated the insecticidal properties of different varieties of kava (Piper methysticum [Frost]) extracted by two methods and the attractive effects of six plant volatiles identified from B. tryoni host plants to female, mated or not. We did not identify any significant insecticidal effect of the traditional Pacific kava plant at the tested concentrations. Among mated females, ethyl acetate compared to the no odor control elicited the highest attraction (87%, of which 60% for this odor), while ethyl butyrate was preferred compared with ethyl acetate in dual choice assays. Flies' preferences for specific odors depended on their mating status and the odor landscape they were confronted with. Combination with the commercial ingestion insecticide (Success 4: spinosad, 480 g/l, Dow AgroSciences, Valbonne, France) with the plant volatiles were tested to detect an increase in mortality related to the addition of an attractant. The 2-heptanone slightly showed a tend to increase the attractiveness of mated females within 4-6 h to the food bait, but the results were not statistically significant after 8 h. Further tests should be performed with other concentrations or mixtures of the identified host plant volatiles to develop a strong lure and kill strategy.

A review on natural phenylbutanoid attractants: Occurrence, distribution, and role in nature, especially in relation to Dacini fruit fly behavior and pollination.

The natural occurrence, distribution (within a plant) and roles of four phenylbutanoid compounds (anisyl acetone, cue-lure, raspberry ketone and zingerone) are elucidated for the Asia-Pacific and Oceania regions. These phenylbutanoids may act individually or in combination to attract true fruit fly males belonging to a tribe Dacini of subfamily Dacinae (Diptera: Tepritidae). Of special interest are the mutualistic interactions between the Dacini fruit fly males and the tropical daciniphilous (attracting exclusively Dacini fruit flies) orchids - leading to cross pollination for the orchids and enchanced mating success for the flies. When offered to male flies, anisyl acetone and cue-lure are generally converted to raspberry ketone. Upon consumption, raspberry ketone and zingerone are individually sequestered in the male rectal (pheromonal) gland unchanged. Attracted male flies readily imbibe the phenylbutanoid(s) in the floral synomone to compliment the endogenously synthesized male sex pheromonal components - to enhance attraction of conspecific females during courtship as well as attract conspecific males to form 'leks'. The phenylbutanoid(s) may also act as an allomone to deter vertebrate predators, especially geckos, besides possessing antimicrobial and antioxidant activities. Cue-lure, raspberry ketone and zingerone are important attractants/lures used in pest surveillance and mass trapping under the integrated pest management (IPM) program against quarantine Dacini fruit fly pest species, particularly Bactrocera tryoni and Zeugodacus cucurbitae.

Larval competition between three endemic fruit flies (Diptera: Tephritidae) of differing phylogenetic relatedness

AbstractWithin a fruit, fruit fly larvae can be subject to scramble competition, in which density‐dependent effects can influence the fitness of subsequent adults. While there is significant research on tephritid interspecific larval competition, it has been conducted in invasive situations where the species are evolutionarily novel to each other. There has been no published research investigating larval competitive interactions between naturally coexisting, endemic species. We ran laboratory‐based, intraspecific and interspecific larval competition trials involving three co‐occurring Bactrocera species of differing genetic relatedness and also measured aspects of juvenile development rate to test possible mechanisms of competitive difference. Larval density had an influence on intraspecific competition in Bactrocera tryoni, Bactrocera neohumeralis and Bactrocera jarvisi, with a decreasing percentage of pupation with increasing larval density. Interspecific competition between B. tryoni and B. neohumeralis, and between B. tryoni and B. jarvisi was influenced by the interaction between species and density. The intensity of competition between B. tryoni and B. neohumeralis was minimal but high between B. tryoni and B. jarvisi. B. jarvisi produced larger eggs and had faster initial larval growth rates than the other two species, but it took the longest time for pupation to occur. Our results conflict with theory, as the greatest competition was observed between the two more distantly related species (B. tryoni and B. jarvisi) rather than between the two most closely related species (B. tryoni and B. neohumeralis). Further, and contrary to other studies, egg size, hatch rate and larval growth rate did not provide B. jarvisi with a competitive advantage; thus, larval size does not appear to be a mechanism of larval competition between B. tryoni and B. jarvisi.

Conservation of shibire and RpII215 temperature-sensitive lethal mutations between Drosophila and Bactrocera tryoni.

The sterile insect technique can suppress and eliminate population outbreaks of the Australian horticultural pest, Bactrocera tryoni, the Queensland fruit fly. Sterile males mate with wild females that produce inviable embryos, causing population suppression or elimination. Current sterile insect releases are mixed sex, as the efficient removal of unrequired factory-reared females is not yet possible. In this paper, we assessed the known Drosophila melanogaster temperature-sensitive embryonic lethal alleles shibire (G268D, shits1) and RNA polymerase II 215 (R977C, RpII215ts) for potential use in developing B. tryoni genetic sexing strains (GSS) for the conditional removal of females. Complementation tests in D. melanogaster wild-type or temperature-sensitive genetic backgrounds were performed using the GAL4-UAS transgene expression system. A B. tryoni wild-type shibire isoform partially rescued Drosophila temperature lethality at 29°C by improving survivorship to pupation, while expressing B. tryoni shits1 failed to rescue the lethality, supporting a temperature-sensitive phenotype. Expression of the B. tryoni RpII215 wild-type protein rescued the lethality of D. melanogaster RpII215ts flies at 29°C. Overexpressing the B. tryoni RpII215ts allele in the D. melanogaster wild-type background unexpectedly produced a dominant lethal phenotype at 29°C. The B. tryoni shibire and RpII215 wild-type alleles were able to compensate, to varying degrees, for the function of the D. melanogaster temperature-sensitive proteins, supporting functional conservation across species. Shibire and RpII215 hold potential for developing insect strains that can selectively kill using elevated temperatures; however, alleles with milder effects than shits1 will need to be considered.

Host reproduction number as an indicator of reproductive advantage in Bactrocera dorsalis over Bactrocera tryoni – can the concept elucidate the invasive threat in northern Australia?

Incursions by exotic tephritids continue to threaten Australia. Host suitability for a specific tephritid is ranked by the number of adults which can emerge from one kg of fruit or the Host Reproduction Number (HRN). Bactrocera dorsalis has previously invaded northern Australia but was eradicated. However, Bactrocera dorsalis remains the largest exotic threat and is likely to invade through northern Australia but B. tryoni and other tephritids are already well established. One question is what hosts would likely provide the best early warning for an exotic incursion. Here, the HRN for 40 hosts for Bactrocera dorsalis and B. tryoni were established from the scientific literature. The reproductive advantages of one species over the other were calculated by dividing the higher HRN by the lower HRN. The fruits with the highest reproductive advantage (> 30) favouring B. dorsalis were soursop, mango and capsicum. The reproductive advantage estimate was compared to surveillance data collected during B. dorsalis eradication in north Queensland from 1995 to 1997. Mangoes and capsicum were among the mostly commonly infested hosts. Capsicums provided the second highest number of samples and would seem ideal candidates as sentinel plants for current surveillance programs. Some inconsistencies are identified and discussed. The HRN and reproductive advantage may have the potential to identify hosts and industries for early warning exotic fruit fly surveillance, better-targeted eradication programs and risk assessments for imports/exports.

An analysis of fruit carried into a quarantine area and an evaluation of infestation rate by Queensland fruit fly Bactrocera tryoni (Froggatt) (Diptera: Tephritidae)

The risk of new establishments of Queensland fruit fly (Qfly), Bactrocera tryoni, in pest-free areas is linked to the fruit carried by road travellers. However, there is little information on what proportion of carried fruit is infested. Previous studies examined the numbers of fruits carried by travellers but not if the fruits were infested. Here, we report on the results of 989 fruit consignments seized on three main entry roads into the Fruit Fly Exclusion Zone and assessed for infestation. We found 1.01% of consignments were infested with tephritids. However, only 0.2% were infested with sufficient Qfly to potentially result in a new establishment. Within the main fruit groups carried, we detected stone fruit, tomatoes, pome fruit, citrus, bananas and tropical fruit in that order. Based on our data and previously published figures, we estimated that there were 1148 consignments infested with tephritids that entered the zone annually. Additionally, we estimated that 227 vehicles carried Qfly-infested fruit consignments into the quarantine zone annually and each of these had the potential to start a new establishment. Our results will help inform managers of quarantine zones.

The hAT family hopper transposon exists as highly similar yet discontinuous elements in the Bactrocera tephritid fly genus.

The hAT family transposable element, hopper, was originally discovered as a defective 3120-bp full-length element in a wild-type strain of the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), and subsequently a functional 3131-bp element, hopperBdwe, was isolated from a white eye mutant strain. The latter study showed that closely related elements exist in melonfly, Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae), a closely related subgenus, suggesting that hopper could have a widespread presence in the Bactrocera genus. To further understand the distribution of hopper within and beyond the B. dorsalis species complex, primer pairs from hopperBdwe and its adjacent genomic insertion site were used to survey the presence and relatedness of hopper in five species within the complex and four species beyond the complex. Based on sequence identity of a 1.94 kb internal nucleotide sequence, the closest relationships were with mutated elements from B. dorsalis s.s. and species synonymized with B. dorsalis including B. papayae, B. philippinensis and B. invadens, ranging in identity between 88.4% and 99.5%. Notably, Bactrocera carambolae (Drew & Hancock) (Diptera: Tephritidae), which is most closely related to B. dorsalis beyond the synonymized species, shared hopper identities of 97.3%-99.5%. Beyond the B. dorsalis complex, Z. cucurbitae,Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) and Bactrocera zonata (Saunders) (Diptera: Tephritidae) shared identities of 83.1%-97.1%, while hopper was absent from the Bactrocera oleae (Gmelin) (Diptera: Tephritidae) strain tested. While the functional autonomous hopperBdwe element was not detected in these species, another closely related hopper element isolated from a B. dorsalis genetic sexing strain has an uninterrupted transposase open reading frame. The discontinuous presence of hopper in the Bactrocera genus has implications for its use for genomic manipulation and understanding the phylogenetic relationship of these species.

Metarhizium spp. isolates effective against Queensland fruit fly juvenile life stages in soil.

Queensland fruit fly, Bactrocera tryoni, Froggatt (Diptera: Tephritidae) is Australia's primary fruit fly pest species. Integrated Pest Management (IPM) has been adopted to sustainably manage this polyphagous species with a reduced reliance on chemical pesticides. At present, control measures are aimed at the adult stages of the fly, with no IPM tools available to target larvae once they exit the fruit and pupate in the soil. The use of entomopathogenic fungi may provide a biologically-based control method for these soil-dwelling life stages. The effectiveness of fungal isolates of Metarhizium and Beauveria species were screened under laboratory conditions against Queensland fruit fly. In bioassays, 16 isolates were screened for pathogenicity following exposure of third-instar larvae to inoculum-treated vermiculite used as a pupation substrate. The best performing Metarhizium sp. isolate achieved an average percentage mortality of 93%, whereas the best performing Beauveria isolate was less efficient, with an average mortality of 36%. Susceptibility to infection during different development stages was investigated using selected fungal isolates, with the aim of assessing all soil-dwelling life stages from third-instar larvae to final pupal stages and emerging adults. Overall, the third larval instar was the most susceptible stage, with average mortalities between 51-98% depending on the isolate tested. Moreover, adult mortality was significantly higher when exposed to inoculum during pupal eclosion, with mortalities between 56-76% observed within the first nine days post-emergence. The effect of temperature and inoculum concentration on insect mortality were assessed independently with candidate isolates to determine the optimum temperature range for fungal biological control activity and the rate required for application in field conditions. Metarhizium spp. are highly efficacious at killing Queensland fruit fly and have potential for use as biopesticides to target soil-dwelling and other life stages of B. tryoni.

Transmission mode predicts coinfection patterns of insect-specific viruses in field populations of the Queensland fruit fly.

Insect-specific viruses (ISVs) can affect insect health and fitness, but can also interact with other insect-associated microorganisms. Despite this, ISVs are often studied in isolation from each other, in laboratory populations. Consequently, their diversity, prevalence and associations with other viruses in field populations are less known, yet these parameters are important to understanding virus epidemiology. To help address this knowledge gap, we assessed the diversity, prevalence and coinfections of three ISVs (horizontally transmitted cripavirus, biparentally transmitted sigmavirus and maternally transmitted iflavirus) in 29 field populations of Queensland fruit fly, Australia's most significant horticultural pest, in the context of their different transmission modes. We detected new virus variant diversity. In contrast to the very high virus prevalence in laboratory populations, 46.8% of 293 field flies carried one virus and 4.8% had two viruses. Cripavirus and sigmavirus occurred in all regions, while iflavirus was restricted to subtropical and tropical regions. Cripavirus was most prevalent (37.5%), followed by sigmavirus (13.7%) and iflavirus (4.4%). Cripavirus coinfected some flies with either one of the two vertically transmitted viruses. However, sigmavirus did not coinfect individuals with iflavirus. Three different modelling approaches detected negative association patterns between sigmavirus and iflavirus, consistent with the absence of such coinfections in laboratory populations. This may be linked with their maternal transmission and the ineffective paternal transmission of sigmavirus. Furthermore, we found that, unlike sigmavirus and iflavirus, cripavirus load was higher in laboratory than field flies. Laboratory and mass-rearing conditions may increase ISV prevalence and load due to increased transmission opportunities. We conclude that a combination of field and laboratory studies is needed to uncover ISV interactions and further our understanding of ISV epidemiology.

Patterns of Variation in the Usage of Fatty Acid Chains among Classes of Ester and Ether Neutral Lipids and Phospholipids in the Queensland Fruit Fly.

Modern lipidomics has the power and sensitivity to elucidate the role of insects' lipidomes in their adaptations to the environment at a mechanistic molecular level. However, few lipidomic studies have yet been conducted on insects beyond model species such as Drosophila melanogaster. Here, we present the lipidome of adult males of another higher dipteran frugivore, Bactrocera tryoni. We describe 421 lipids across 15 classes of ester neutral lipids and phospholipids and ether neutral lipids and phospholipids. Most of the lipids are specified in terms of the carbon and double bond contents of each constituent hydrocarbon chain, and more ether lipids are specified to this degree than in any previous insect lipidomic analyses. Class-specific profiles of chain length and (un)saturation are broadly similar to those reported in D. melanogaster, although we found fewer medium-length chains in ether lipids. The high level of chain specification in our dataset also revealed widespread non-random combinations of different chain types in several ester lipid classes, including deficits of combinations involving chains of the same carbon and double bond contents among four phospholipid classes and excesses of combinations of dissimilar chains in several classes. Large differences were also found in the length and double bond profiles of the acyl vs. alkyl or alkenyl chains of the ether lipids. Work on other organisms suggests some of the differences observed will be functionally consequential and mediated, at least in part, by differences in substrate specificity among enzymes in lipid synthesis and remodelling pathways. Interrogation of the B. tryoni genome showed it has comparable levels of diversity overall in these enzymes but with some gene gain/loss differences and considerable sequence divergence from D. melanogaster.

Genomic signals of local adaptation across climatically heterogenous habitats in an invasive tropical fruit fly (Bactrocera tryoni)

Local adaptation plays a key role in the successful establishment of pest populations in new environments by enabling them to tolerate novel biotic and abiotic conditions experienced outside their native range. However, the genomic underpinnings of such adaptive responses remain unclear, especially for agriculturally important pests. We investigated population genomic signatures in the tropical/subtropical Queensland fruit fly, Bactrocera tryoni, which has an expanded range encompassing temperate and arid zones in Australia, and tropical zones in the Pacific Islands. Using reduced representation sequencing data from 28 populations, we detected allele frequency shifts associated with the native/invasive status of populations and identified environmental factors that have likely driven population differentiation. We also determined that precipitation, temperature, and geographic variables explain allelic shifts across the distribution range of B. tryoni. We found spatial heterogeneity in signatures of local adaptation across various climatic conditions in invaded areas. Specifically, disjunct invasive populations in the tropical Pacific Islands and arid zones of Australia were characterised by multiple significantly differentiated single nucleotide polymorphisms (SNPs), some of which were associated with genes with well-understood function in environmental stress (e.g., heat and desiccation) response. However, invasive populations in southeast Australian temperate zones showed higher gene flow with the native range and lacked a strong local adaptive signal. These results suggest that population connectivity with the native range has differentially affected local adaptive patterns in different invasive populations. Overall, our findings provide insights into the evolutionary underpinnings of invasion success of an important horticultural pest in climatically distinct environments.

Evaluating trap and lure combinations using Biotraps and Lynfield traps for the surveillance of Queensland fruit fly Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) and other tephritids in southern New South Wales, Australia

Fruit fly surveillance remains essential for international and domestic trade. The dry cuelure baited Lynfield trap has been the Australian standard since the early 1990s. Here, we tested the two versions of Biotraps against the Lynfield traps in the Riverina area of New South Wales. The Biotraps using a protein gel performed significantly better in trapping Island fly and female Queensland fruit fly. Also, Biotraps were assessed as at least equal to or superior to Lynfield traps for trapping male Queensland fruit fly. However, the number of Newman fly trapped exhibited no significant difference between the two trap types in both time periods A and B. We discuss differences in trap architecture, toxicants and lures between the two traps, along with benefits for storage and transport.

Female–female aggression in Bactrocera tryoni (Diptera: Tephritidae) and the influence of fruit quality on combat intensity

AbstractFrugivorous tephritid (Diptera: Tephritidae) females compete over access to fruit for oviposition through aggressive interactions. These aggressive displays are for oviposition site maintenance to reduce the probability of subsequent larval competition. While female aggressive behaviours have been described for several frugivorous tephritid species, studies quantifying behavioural frequencies and sequences and examining how quality of the host fruit might modify the intensity of aggressive behaviours are minimal or absent. We used behavioural analysis software of video playback to describe and quantify antagonistic behaviours between pairs of Bactrocera tryoni females and measured changes in the frequency of behaviours when females were defending three fruit types known to vary in their quality for offspring development. Seven behaviours were identified as part of competitive contests between B. tryoni females, which were not performed in any regular order or with any obvious escalation in the intensity of an aggressive display. Crabbing, [wing] supination and pushing were the most common behaviours, constituting 78% of all observed aggressive behaviours. Increasing fruit quality resulted in aggressive behaviours happening significantly sooner and more often. Our results are similar to previous studies in the types of behaviours exhibited by female frugivorous tephritids but are contrary to other studies in that no sequential pattern or escalation of behaviours was documented. Increased female investment in defence of higher quality hosts aligns with theoretical predictions but has not been previously tested.

Priority host plants of the Queensland fruit fly, Bactrocera tryoni (Froggatt), based on the host reproduction number for tephritid management, surveillance and trade

The Host Reproduction Number (HRN) is a measure of the number of adult fruit flies that can emerge from one kilogram of fruit. HRN is a useful tool in surveillance, management and trade. I reviewed the literature for Queensland fruit fly (Qfly) and found data on 297 hosts. There were 81 Qfly hosts with HRN data and 216 Qfly hosts with no HRN data. The HRN will help to inform and triage hosts for target surveillance and management programs. Additionally, HRN will inform disinfestation activities pertaining to incursion response management, risk mitigation and trade options. There is a need for scientists to report HRN in a consistent manner so that Qfly management programs and trade protocols might be optimised.

Raspberry ketone feeding makes Queensland fruit fly, Bactrocera tryoni (Froggatt) more vulnerable to desiccation but not starvation.

Queensland fruit fly (Qfly) males exhibit accelerated sexual maturation when their diet is supplemented with raspberry ketone (RK) for 48 hours following emergence which is beneficial for Sterile Insect Technique (SIT) operation. The present study tests whether RK supplementation makes Qfly more vulnerable to starvation or desiccation. Flies were fed for 48 hours with yeast hydrolysate and sugar diet (1:3) that contained 0% RK (control), 1.25% RK (low dose) or 5% RK (high dose) to test subsequent vulnerability to starvation and desiccation. RK feeding decreased body weight and water content in males and increased lipid levels in both sexes before exposure to any stress treatment. Under nutritional stress, flies fed the low RK dose, but not the high RK dose, had higher survival than controls. Under desiccation stress, flies fed both the low and high RK doses had lower survival than the controls. Body weight, water content and lipid reserves at death were all affected by RK dose when under nutritional stress, but not when under desiccation stress. In the absence of stress, body weight at death was higher than controls in flies provided the high RK dose and lipids were lower than controls in flies provided the low RK dose. Feeding with RK makes Qflies more vulnerable to desiccation but not starvation. In most conditions, it is expected that the disadvantage of increased desiccation vulnerability would be outweighed by the benefits of accelerated sexual maturation in RK-fed young adult Qflies. This article is protected by copyright. All rights reserved.