Bulletin of Entomological Research (2016) 106, 818-826

J. Rull, E. Tadeo, R. Lasa and M. Aluja (2016)
The effect of winter length on survival and duration of dormancy of four sympatric species of Rhagoletis exploiting plants with different fruiting phenology
Bulletin of Entomological Research 106 (6), 818-826
Abstract: Dormancy has been thoroughly studied for several species of economic importance in the genus Rhagoletis in temperate areas of North America and Europe. Much less is known on life history regulation for species inhabiting high-elevation areas in the subtropics at the southern extreme of their geographical range. Host plant phenology has been found to play a key role in generating allochronic isolation among sibling species and host races of Rhagoletis in the course of sympatric speciation, and has important implications for pest management. We compare the effect of winter length on survival to adult eclosion and dormancy duration among four species of Rhagoletis (three of them sympatric) exploiting hosts with different fruiting phenology in subtropical isolated highlands. Survival and duration of dormancy was found to be different among the four species. At 24°C, a very small proportion (<1%) of R. pomonella, R. turpiniae and R. zoqui completed development without becoming dormant, while in the case of R. solanophaga the majority of the population emerged after development within 40 days of pupation. Also, a large proportion of braconid parasitoids infesting Rhagoletis eggs and larvae emerged as adults without becoming dormant. Greatest survival after artificial winter was obtained for R. pomonella (50–60%) and R. zoqui (30%) after only four weeks at 5°C (a third of the time reported for studies on northern R. pomonella), while R. turpiniae, under identical environmental conditions experienced low adult emergence, and highest survival (11%) was recorded for flies exposed to 5°C during 10 and 12 weeks. For R. pomonella, there was a strong positive relationship between winter length and time to post-winter adult eclosion that was not observed for R. zoqui. In sum, for R. pomonella, mild winters in highland subtropical areas appear to select for flies better able to withstand longer periods of warm temperature before winter than flies exploiting late fruiting hosts and inhabiting northern latitudes. In the case of R. turpiniae and R. zoqui environmental cues such as fluctuations in humidity and/or different temperature thresholds (5°C) may play a more important role than winter length in life history regulation. Continuous host availability for R. solanophaga appears to have selected for non-diapausing flies. From an applied perspective our results are useful for handling flies in the laboratory to conduct research and suggest that non-diapausing strains of flies and parasitoids may be selected for SIT and innundative biological control programs.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Martín Aluja, Rodrigo Lasa

Research topic(s) for pests/diseases/weeds:
population dynamics/ epidemiology
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Rhagoletis pomonella
	Rhagoletis zoqui