ORCID Profile
0000-0001-6340-5513
Current Organisation
NSW Department of Primary Industries
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Publisher: Wiley
Date: 05-02-2023
DOI: 10.1111/AAB.12818
Abstract: Host plants used by phytophagous insects can have significant consequences on demography parameters, overall lifetime fitness and their subsequent population dynamics. Here, we conduct a comparative demographic study between the specialist Zeugodacus cucumis (French) and generalist Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) to determine whether the host plants used by these fly species play any role in their overall lifetime fitness and explains current host use patterns. These two fly species are pests within the north‐eastern region of Australia and we further aimed to use complete life‐history data to determine the population parameters and models that would help identify the sensitive life‐history stage that could be targeted for effective field management. Eggs collected from laboratory‐reared flies were inoculated into organically grown fruits of both the primary and alternate host plant cultivars of both fly species. The proportion surviving each life stage from egg through to adult and fecundity were monitored for all cohorts from the different plant cultivars. Complete stage‐base life‐tables for cohorts of each fly species developing from each fruit cultivar were constructed, and the key demographic parameters and population models were analysed using PopTools matrix model programme. Our results showed that the host used by each fly species had significant consequences on fly demographic parameters and hence their overall lifetime fitness. The generalist B. tryoni was able to compensate for the fitness loss experienced at the pre‐adult stage by having adults with higher fecundity, but this was not the case for the specialist Z. cucumis . Stage‐base population models revealed that the population growth rate of both species was highly sensitive at the adult reproductive stage, indicating that manipulating probability of survival at this life stage would effectively manage populations of these pest species. This study provides the empirical evidence of undertaking complete life history demography studies of phytophagous insects to accurately understand their lifetime fitness consequences of using a certain host, their observed host use patterns, and overall population dynamics. We suggest that any efforts to manage dacine fruit fly pest population should consider life‐history consequences of host use.
Publisher: Cold Spring Harbor Laboratory
Date: 31-08-2023
DOI: 10.1101/2023.08.30.555036
Abstract: Background : Lineage theory suggests that the development of traits associated with reproductive isolation coupled with traits associated with ecological differentiation are essential for the maintenance of sympatric lineages. However, the relative importance of these factors has rarely been tested simultaneously. Bactrocera tryoni and B. neohumeralis are a tephritid fruit fly species pair that have significant overlap in geographic range and host use, with time of male mating the only known difference in their mating systems. Using this system, we tested the relative importance of ecological differentiation versus assortative mating in sympatric lineage maintenance. Results : Genome-wide SNP analyses found strong genetic differentiation between the species with no evidence for hybridization in the field. Most outlier SNPs were restricted to narrow regions towards the centromeres and telomeres of chromosomes. Enrichment of annotation terms indicated an overabundance of genes with the abnormal neuroanatomy term. Terms of interest associated with sleep and circadian rhythm, potentially important to the allochronic reproductive barrier, were non-enriched. Ecological data found no evidence for ecological ergence or competitive displacement between the two species based on significant positive correlations between species numbers trapped at different times of the year, trapped in different habitats within a region, or when reared from fruit. Conclusions : Our study highlights the significance of assortative mating over ecological differentiation for sympatric lineage maintenance of the B. tryoni/B. neohumeralis sibling pair. The paper represents one of the most well-characterized ex les of the importance of genomic ergence in the coexistence of two closely related species.
Publisher: Wiley
Date: 21-07-2021
DOI: 10.1111/AEN.12561
Abstract: Queensland fruit fly (Qfly), Bactrocera tryoni (Froggatt), is a major quarantine pest of fresh horticultural commodity along the eastern coastal region of Australia and restricts market access of its host commodity. Consequently, various post‐harvest disinfestation treatments are used to facilitate trade and one such treatment for Qfly is ‘cold disinfestation’. Our study evaluated the effect of cold storage as a post‐harvest disinfestation treatment for Qfly on ‘gold3’ kiwifruit ( Actinidia chinensis var. gold3‐sungold), a cultivar grown in New Zealand. Qfly is not present in New Zealand but due to its close proximity to Australia, New Zealand's trading partners have shown concern that Qfly presents a biosecurity risk to their own industry. Our study specifically aimed to demonstrate how this risk would be addressed. Experiment 1 investigated developmental rate of the in idual life stages of Qfly in ‘gold3’ kiwifruit under optimal Qfly development conditions of 26 ± 1°C and 65 ± 5% rh, while experiment 2 focused on determination of the most cold tolerant life stage of Qfly in ‘gold3’ kiwifruits. Experiment 3 was a large‐scale confirmatory trial undertaken using the most cold tolerant life stage. The results revealed that Qfly successfully developed in ‘gold3’ kiwifruit and that the most‐cold tolerant Qfly life stage was the 1st instar. Our study further demonstrated that storage of ‘gold3’ kiwifruit at 2.5°C (fruit temperature) for a period of ≥12 days resulted in zero Qfly survival. The large‐scale verification trial treated 61,412 first instar and confirmed that storage of ‘gold3’ kiwifruit at 2.5°C for a 14‐day period resulted in 99.9951% mortality of first instar at the 95% confidence level, hence demonstrating a probit 8.7 level of efficacy. A 14‐day cold storage period was used in this confirmatory trial to ensure additional quarantine security. We recommend that if there was any Qfly infestation on ‘gold3’ kiwifruit, a post‐harvest quarantine treatment of cold storage at 2.5°C (fruit temperature) for a 14‐day period must be used to disinfest Qfly from ‘gold3’ kiwifruit.
Publisher: Elsevier BV
Date: 2022
No related grants have been discovered for Solomon Balagawi.