Lloyd Stringer

BSc & MSc (Hons) Victoria University of Wellington NZ,

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Doctoral Candidate - Doctor of Philosophy


I have an MSc (Hons) in Ecology and Biodiversity from Victoria University in Wellington NZ. My MSc was on the effect of the Australian Monomorium sydneyense ant on competitive dynamics in a recently invaded area of NZ (2004-05). I am based at Plant & Food Research (Lincoln), where I work in the Biosecurity group, investigating surveillance and eradication options for a variety of insect pests including ants, wasps, moths and flies. I am a doctoral candidate at UoA investigating how population management tools interact with Allee thresholds.

Research | Current

How population management tools interact with Allee thresholds?


Jacqueline Beggs (University of Auckland)

Max Suckling (Plant and Food Research/University of Auckland)

John Kean (AgResearch)


Successful eradications are usually expensive exercises. When the incursion area is small, one eradication tool may do the job, but for larger areas, a suite of tactics used either stepwise or concurrently may be more efficient due to synergistic interactions, reducing overall cost and time taken to achieve eradication. For example the sterile insect technique (SIT), whereby sterile insects are released to mate with wild conspecifics to reduce population size, may not be appropriate when there is a large population due to rearing and release costs. However, a broad spectrum insecticide for the initial population knock down of the invading pest prior to SIT may increase the over-flooding ratio, the ratio between sterile and wild insects. By increasing the over-flooding ratio in favour of the steriles, the likelihood of mating occurring between a sterile and a wild insect increases, leading to a reduction of the wild population. The addition of a Bacillus thuringiensis (Bt) spray, concurrent with SIT, may further enhance SIT as Bt only affects the larvae (unlike concurrent use of broad spectrum insecticides that would kill a proportion of the released sterile insects). Further, it may not be necessary to kill every last individual as Allee effects, such as but not limited to, the inability to find mates, may lead to further population reductions. Once a population’s density is reduced below a critical threshold required for positive population growth, any further interference by managers won’t be required, as the population will become extinct of its own accord.

My PhD project will combine theoretical and experimental approaches to expand knowledge of how combinations of tactics can be best used during eradication. I will investigate the mate-finding Allee thresholds for two species: the economically damaging Queensland fruit fly (Qfly; Bactrocera tryoni) and Drosophila simulans, a cosmopolitan species, as a model for the invasive pest D. suzukii under various population management regimes.

Areas of expertise

Invasive species detection and eradication

Chemical ecology

Selected publications and creative works (Research Outputs)

  • Suckling, D. M., Stringer, L. D., Jiménez-Pérez A, Walter, G. H., Sullivan, N., & El-Sayed, A. M. (2018). With or without pheromone habituation: Possible differences between insect orders?. Pest Management Science, 74 (6), 1259-1264. 10.1002/ps.4828
    Other University of Auckland co-authors: Max Suckling
  • Stringer, L. D., Harland, D. P., Grant, J. E., Laban, J., & Suckling, D. M. (2017). Effect of 40Gy irradiation on the ultrastructure, biochemistry, morphology and cytology during spermatogenesis in the southern green stink bug Nezara viridula (Hemiptera: Pentatomidae). 10.1101/171991 https://pdfs.semanticscholar.org/58c1/730983d9e342b6a08150a4018e49250620a3.pdf.
    Other University of Auckland co-authors: Max Suckling
  • Stringer, L. D., Corn, J. E., Roh, H. S., Jiménez-Pérez A, Manning, L. M., Harper, A. R., & Suckling, D. M. (2017). Thigmotaxis mediates trail odour disruption. Scientific Reports, 710.1038/s41598-017-01958-z
    URL: http://hdl.handle.net/2292/34600
    Other University of Auckland co-authors: Max Suckling
  • Smith, G. R., Fletcher, J. D., Marroni, V., Kean, J. M., Stringer, L. D., & Vereijssen, J. (2017). Plant pathogen eradication: determinants of successful programs. Australasian Plant Pathology, 46 (3), 277-284. 10.1007/s13313-017-0489-9
    URL: http://hdl.handle.net/2292/34613
  • Welsh, T. J., Stringer, L. D., Caldwell, R., Carpenter, J. E., & Suckling, D. M. (2017). Irradiation biology of male brown marmorated stink bugs: Is there scope for the sterile insect technique?. International Journal of Radiation Biology, 93 (12), 1357-1363. 10.1080/09553002.2017.1388547
    Other University of Auckland co-authors: Max Suckling
  • Stringer, L. D., Kean, J. M., Beggs, J. R., & Suckling, D. M. (2017). Management and eradication options for Queensland fruit fly. Population Ecology10.1007/s10144-017-0593-2
    URL: http://hdl.handle.net/2292/40456
    Other University of Auckland co-authors: Jacqueline Beggs, Max Suckling
  • Stephens, A. E. A., Stringer, L. D., & Suckling, D. M. (2016). Advance, retreat, resettle? Climate change could produce a zero-sum game for invasive species. Austral Entomology, 55 (2), 177-184. 10.1111/aen.12162
    URL: http://hdl.handle.net/2292/28999
    Other University of Auckland co-authors: Max Suckling
  • Suckling, D., Kean, J., Stringer, L., Cáceres‐Barrios C, Hendrichs, J., Reyes‐Flores J, & Dominiak, B. (2016). Eradication of tephritid fruit fly pest populations: Outcomes and prospects. Pest Management Science, 72 (3), 456-465. 10.1002/ps.3905
    URL: http://hdl.handle.net/2292/31441
    Other University of Auckland co-authors: Max Suckling

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