Author
Robyn White
whiter@landcareresearch.co.nz
Bioeconomy Science Institute – Manaaki Whenua – Landcare Research Group
Christchurch, New Zealand
Coauthors
Zane McGrath, Bioeconomy Science Institute – Manaaki Whenua – Landcare Research Group, Auckland, New Zealand
Abstract
The air potato (Dioscorea bulbifera) is a major invasive weed that can be controlled by the air potato leaf beetle (Lilioceris cheni). We have identified the presence of gregarines (Apicomplexa: Gregarinasina) in laboratory and field colonies. Gregarines occupy a spectrum of symbiotic relationships, and their presence raises a critical dilemma for mass-rearing: If the organisms are parasitic, high infection prevalence may negatively impact host fitness and diminish biocontrol efficacy. Conversely, if they act as mutualists, removing them may negatively alter the beetle’s essential gut biota and compromise successful establishment and efficacy. Rearing a “disease-free” colony is necessary for release in some jurisdictions, but the ecological consequences of removal are currently unknown.
Our initial step is to test the feasibility of eliminating gregarines from a rearing population. The most common transmission route is thought to be faecal-oral. We hypothesise that surface contamination of the egg shell by oocysts is the critical vector for early-stage infection. Our primary objective is to determine if surface-sterilising L. cheni eggs breaks the transmission cycle.
The presentation will discuss our knowledge of gregarines in L. cheni to date, detail any recent findings, and explore the implications for biocontrol programmes.
keywords
gregarines
disease
microbiota
biocontrol
Highlights
Disease screening in biocontrol agents
Attempt to remove gregarines
Could removing gregarines affect biocontrol negatively or positively?