On basis of location, host, and morphology the two known collections are conspecific. (Cunningham 1922, Dingley 1953)
Sequence data from the 2014 specimen of C. kirkii for nSSU, nLSU, TEF, RPB1, and RPB2 was incorporated into the Sanjuan et al. (2014) phylogenetic paper on orthopteran Cordyceps of Columbia. C. kirkii is confirmed as a true Cordyceps, but phylogentically distinct from the Colombian orthoptera-associated species. No genetic data is known for other New Zealand species of Cordyceps.
The pathogen Cordyceps kirkii is known from only the holotype (collected 1922) and a second specimen (collected 2014). Both collections are from same small island, Stephens Island, Marlborough Sounds, New Zealand, and from the same host - the threatened Stephens Island Weta, Deinacrida rugosa (Categorised as globally VU (Vulnerable) in 1996 by IUCN).
Preliminary red-list assessment; DD (Data Deficient)
Thanks to the “Threatened Weta recovery plan”, the population size and the distribution of the Weta, the host of C. kirkii, has increased since 1996 and is expanding. Hence, the habitat and therefore also the potential population size of C. kirkii is increasing. However, only two collections have been made of the species, the knowledge of its commonness and distribution within the range of its host is unknown, hence also the status. It could possibly qualify for VU2 (very few localities, area of occupancy or no of mature individuals, if including an estimate of the unrecorded portion of the population). However, at this stage, we rather suggest DD.
Known to date from only one near-offshore island of New Zealand - Stephens Island is 150 ha in size.
Although the obligate host is present on 4 other small islands and 2 islets, Cordyceps has not been recorded from these and may not have been searched for at these locations.
Population status and trend unknown. Obligate host, however, is confined to 5 rodent-free islands and 2 islets in New Zealand, plus recent translocations. - see regional status. Arguably the Cordyceps is more threatened that the “Vulnerable” (IUCN-rated) host.
Population Trend: Uncertain
On the basis of only two known specimens, the species is apparently confined to a single obligate host: Deinacrida rugosa (Stephens Island Giant Weta; Cook Strait Weta). Presumably parasitic, and sporulating on dead weta.
The Cook Strait Weta prefers dense grassland and low growing shrubs in open situations. On Mana Island, they now occur in rank grass and shrubland
including tauhinu (Cassinia leptophylla). Predators include reptiles and birds. (from http://www.doc.govt.nz/Documents/science-and-technical/tsrp25.pdf)
Population decline of only known host, Deinacrida rugosa due to invasive predators (e.g., mice, rats, cats). Host confined to certain offshore, rodent free nature reserve islands - exotic predator-free status needs to be maintained indefinitely. Translocation of host to other reserve islands and recently to mainland predator-free reserve has been successful. A population explosion of the native and also threatened reptile Tuatara, that eat weta, could also potentially diminish the weta population at a local level.
No conservation actions have been undertaken specifically for Cordyceps kirkii.
However, there has been active conservation effort to support survival of the host Deinacrida rugosa, including on Stephens Island (Takapourewa Nature Reserve) where both specimens of the Cordyceps were collected. This island holds the world’s largest population of tuatara, that naturally prey on weta and other invertebrates. Other species found there include fairy prion, seven species of lizard and the endemic Hamilton’s frog (though latter too small to consume weta).
Conservation initiatives to support the Stephens Island / Cook Strait Giant Weta (from Sherley (1998) http://www.doc.govt.nz/Documents/science-and-technical/tsrp25.pdf):
“Cook Strait giant weta (Deinacrida rugosa) A self-sustaining and expanding population has been established by translocating weta from Mana Island to Maud Island. Transfer of weta from Mana Island to Somes Island was initiated in 1996. Captive breeding techniques have been developed. Field research on dispersal behaviour and habitat use has been completed. Mice (presumed to prey on weta) have been removed from Mana Island which is considered to be the species stronghold”
“Distribution and abundance: Deinacrida rugosa is found on five rodent-free islands and two islets in the Cook Strait vicinity; North, South and Middle Trio
Islands, Stephens Island, Maud Island, Matiu/Somes Island, and Mana Island. This weta is abundant on Mana Island, and healthy populations are also present Stephens and Middle Trio Island. The population on Maud Island was introduced in 1976, and is increasing (Meads and Notman 1992a). D. rugosa was introduced to Matiu/Somes Island in 1996.”
Basic understanding of biology of species, and its interaction with its host.
Search on other island habitats of host to evaluate distribution of Cordyceps.
Evaluating population size
Phylogenetic relationships of New Zealand Cordyceps in global context
Cunningham, G.H. 1922: A singular Cordyceps from Stephen Island, New Zealand. Transactions of the British Mycological Society 8(1-2): 72-75
Dingley, J.M. 1953: The Hypocreales of New Zealand. V. The genera Cordyceps and Torrubiella. Transactions of the Royal Society of New Zealand 81(3): 329-343.
Sanjuan, T. et al. 2014: Entomopathogens of Amazonian stick insects and locusts are members of the Beauveria species complex (Cordyceps sensu stricto). Mycologia (in press), doi:10.3852/13-020. http://www.mycologia.org/content/early/2014/01/23/13-020.full.pdf
Sherley, G.H. (1998) Threatened Weta Recovery Plan. Threatened Species Recovery Plan no. 25. Department of Conservation, Wellington, New Zealand. http://www.doc.govt.nz/Documents/science-and-technical/tsrp25.pdf