Genetic relations between outbreaks of the Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), in Adelaide in 2000 and 2002

Abstract

The Queensland fruit fly (Q-fly), Bactrocera tryoni , is a serious horticultural pest throughout eastern Australia, and apart from isolated outbreaks, is absent from Adelaide and South Australia. Considerable resources are put into preventing the entry of Q-fly into South Australia and the eradication of any outbreaks. Nevertheless, some flies are still trapped in Adelaide and, because known permanent populations are too distant for unaided dispersal, these flies must arrive as larvae in infested fruit. To provide authorities with more information on the nature of and the extent of outbreaks, the authors used 26 microsatellite markers to test the relationships between outbreak flies caught in Adelaide in 2000 and 2002. Groupings between individuals were tested using both a model-based clustering method (implemented in the Structure program) and relatedness testing, using both simple exclusion tests and relatedness coefficients. While many flies appeared unrelated, one group of at least six full sibs was detected, all of which were trapped in the same month. Unexpectedly, these six flies were trapped at sites separated by distances greater than the unaided dispersal distance of Q-fly, implicating human-aided dispersal of infested fruit within Adelaide. Thus simultaneous trappings of flies separated by kilometres are not necessarily separate outbreaks as has been assumed. The implications for current outbreak control strategies are discussed.

Using variation in wing shape to distinguish between wild and mass‐reared individuals of Queensland fruit fly, Bactrocera tryoni

“…This contrasts with tests based on differences in testes morphology (expected to be greatly reduced in sterile flies) that are unreliable because fly bodies may remain in traps for up to 2 weeks, during which time desiccation obscures soft‐tissue morphology. The wing shape test is also much cheaper and faster than DNA microsatellite markers (which can nevertheless be used to distinguish the current sterile strain from wild flies but take 5–10 days; e.g., Gilchrist et al., 2004). Data collection for wing shape analysis is both relatively cheap (requiring only microscope mounted video‐camera) and fast: several hundred wings can be digitised and analysed on the same day (e.g., Houle et al., 2003).…”

Analysis of olive fly invasion in California based on microsatellite markers

“…Microsatellites are particularly informative in the study of recent population phenomena, such as biological invasions (Bruford and Wayne, 1993;Schlö tterer and Pemberton, 1994;Tautz and Schlötterer, 1994). Moreover, they have been successfully used in the analysis of population structure of different Tephritidae species, such as Ceratitis capitata (Bonizzoni et al, 2001;Gasperi et al, 2002), Bactrocera dorsalis (Aketarawong et al, 2007) and B. tryoni (Yu et al, 2001;Gilchrist et al, 2004). In the case of C. capitata, they have provided guidance in establishing the source of recent invasions in different parts of the world (Meixner et al, 2002;Bonizzoni et al, 2004).…”

MarkingBactrocera dorsalis(Diptera: Tephritidae) with Fluorescent Pigments: Effects of Pigment Colour and Concentration

“…This may partly result from the blockage of respiratory surfaces by fine dust particles (Weldon 2005). Excessive dye particles on released marked flies may also influence recapture results as unmarked wild flies can be misidentified as released sterile flies when they collect dye particles in traps (Gilchrist et al 2004;Chen et al 2016). International standards set for pigment marking of tephritid flies for SIT have been reduced from a recommended concentration of Day-Glo ® powder of 2.0-2.5 g/l pupae in 1999 (FAO/IAEA/USDA 1999) to 1.5 g/l pupae in 2003 (FAO/IAEA/USDA 2003).…”