Pseudococcus markharveyi Gullan, 2013
Banksia montana mealybug
Taxonomy & Nomenclature
Synonym/s: Pseudococcus sp. 15 (Moir et al., 2012)
Conservation Status
Missing (Moir, 2021)
Last record: November 2019 (Moir, 2021)
This species was only discovered in the Stirling Range in 2007 (Gullan et al., 2013), and was discussed in the literature prior to its scientific description as Pseudococcus sp. 15 (Moir et al., 2012). Its only known host (Banksia montana) is critically endangered due to dieback (Phytophthora cinnamomi) and increasingly frequent/intense fires, with only a few dozen plants (45 mature, 16 young) extant around the time it was discovered (Gillfillian et al., 2005; Gullan et al., 2013), leading to P. markharveyi being likewise considered critically endangered (Gullan et al., 2013; Moir & Leng, 2015). The species comprised two small populations c.7km apart (Bluff Knoll & Pyungorup Peak), with no evidence of dispersal between these sites which were likely continuous in the past prior to a recent increase in fire frequency/extent. Plans were thus underway to translocate individuals to create an insurance population more than 30km south (Moir et al., 2012), with a first attempt using first and second instars failing (Moir & Leng, 2013) and a second attempt using adults also later failing (Moir, 2021).
At their natural sites, the species appeared to exclusively occupy older B. montana at Bluf Knoll and to not disperse to younger plants, likely due to the very low density of plants that did not create contact ‘bridges’ from one plant to the next for the species to traverse (Moir, 2021; Marsh et al., 2023), due to the increased rate at which the host plants were being burned relative to their natural rate of regeneration (Marsh et al., 2023), leading to fragmentatoon of stands of B. montana and thus exacerbating the species’ poor dispersal ability in the absence of ideal conditions (Moir et al., 2021; Marsh et al., 2023).
In 2018, a controlled burn got out of control and burned one of the sites, and in late December 2019–early January 2020, 40,000ha of bush was burnt by a series of fires, destroying the other known population (Moir, 2021; Marsh et al., 2023). The only hope for the species would be to discover that it is not host-specific and can thus occupy other Banksia sp. Indeed, there is a potential third population in the Fitzgerald River National Park c.135km to the east, where mealybugs of an unknown species were discovered in 1985, but so far only nymphs have been found that appear to be genetically non-identical to P. markharveyi, but adult specimens are needed to confirm or reject this.
Distribution
Stirling Range National Park (Bluff Knoll and Pyungorup Peak), Western Australia, Australia
Biology & Ecology
Hypodigm
Media
References
Original scientific description:
Gullan, Penny J., Moir, Melinda L. and Leng, M. C. (2013). A new species of mealybug (Hemiptera: Pseudococcidae) from critically endangered Banksia montana in Western Australia. Records of the Western Australian Museum 28(1): 13-20.
Other references:
Gilfllian, S. et al. (2005). Strling Range Dryandra (Dryandra montana) Recovery Plan. Department of Environment and Conservaton, Albany. 23 pp.
Marsh, Jess R., Bal, Payal, Fraser, Hannah, Greenville, Aaron, Latty, Tanya, Moir, Melinda L., Rumpff, Libby, Umbers, Kate and Woinarski, John C. Z. (2023). Impacts of the 2019–20 wildfires on Australian invertebrates, pp. 141-153. In: Rumpff, Libby, Legge, Sarah M., van Leeuwen, Stephen, Wintle, Brendan A. and Woinarski, John C. Z. (eds.). Australia's Megafires: Biodiversity Impacts and Lessons from 2019-2020. Clayton South, Victoria: CSIRO Publishing.
Moir, Melinda L. (2021). Coextinction of Pseudococcus markharveyi (Hemiptera: Pseudococcidae): a case study in the modern insect extinction crisis. Austral Entomology 60(1): 89-97. https://doi.org/10.1111/aen.12506
Moir, Melinda L. and Leng, M. C. (2013). Developing management strategies to combat increased coextinction rates of plant-dwelling insects through global climate change. National Climate Change Adaptation Research Facility, Gold Coast, QLD. 104 pp.
Moir, Melinda L. and Leng, M. C. (2015). Pseudococcus markharveyi. The IUCN Red List of Threatened Species 2015: e.T68974289A68974294. https://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T68974289A68974294.en. Accessed on 06 August 2022.
Moir, Melinda L., Vesk, P. A., Brennan, K. E. C. et al. (2012). A preliminary assessment of changes in plant-dwelling insects when threatened plants are translocated. Journal of Insect Conservation 16: 367-377.