The Rhagoletis pomonella species complex is one of the foremost examples supporting the occurrence of sympatric speciation. A recent study found that reciprocal F(1) hybrid offspring from different host plant-infesting populations in the complex displayed significantly reduced olfactory host preference in flight-tunnel assays. Behavioral and electrophysiological studies indicate that olfactory ...

Studies were conducted to examine the deposition of microcapsules and the attractiveness of treated apple leaves, Malus domestica Borkhausen, for codling moth, Cydia pomonella L., after low-volume concentrated sprays [24.7 g (AI) in 12 liters of water/ha] of a microencapsulated (MEC) sex pheromone formulation (CheckMate CM-F). Nearly 30% of leaves collected from sprayed zones within tree canopi...

Rhagoletis pomonella (Walsh) (Diptera: Tephritidae) is a quarantine pest of apple (Malus sp.) inWashington state that is almost identical morphologically to Rhagoletis zephyria Snow, a nonpest of apple. Historically, the longer ovipositor inR. pomonella has been used to separate it from R. zephyria, despite overlap in ovipositor lengths. Here, the objectives were to determinewhether use of mult...

sympatric host race formation in the apple maggot fly, Rhagoletis pomonella. Genetics 163, 939–953 5 Linn, C. et al. (2003) Fruit odor discrimination and sympatric host race formation in Rhagoletis. Proc. Natl. Acad. Sci. U. S. A. 100, 11490–11493 6 Feder, J.L. et al. (1988) Genetic differentiation between sympatric host races of the apple maggot fly Rhagoletis pomonella. Nature 336, 61–64 7 No...

Apple maggot, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae), is a pest of major concern to apple, Malus x domestica (Borkh.) production in eastern North America. Host plant resistance to apple maggot among apple germplasm has been previously evaluated among a small number of exotic Malus accessions and domestic hybrid selections. However, a large number of exotic accessions housed in USDA...

Industry concerns over insect resistance, regulatory action, and the needs of organic processors have renewed interest in nonchemical alternative postharvest treatments to fumigants used for California tree nuts. The development of inexpensive polyvinyl chloride containers capable of holding low pressures has increased the practicality of vacuum treatments for durable commodities such as tree n...

Insects use chemical signals to find mates, food and oviposition sites. The main chemoreceptor gene families comprise odorant receptors (ORs), ionotropic receptors (IRs) and gustatory receptors (GRs). Understanding the evolution of these receptors as well as their function will assist in advancing our knowledge of how chemical stimuli are perceived and may consequently lead to the development o...

Whether phytophagous insects can speciate in sympatry when they shift and adapt to new host plants is a controversial question. One essential requirement for sympatric speciation is that disruptive selection outweighs gene flow between insect populations using different host plants. Empirical support for host-related selection (i.e., fitness trade-offs) is scant, however. Here, we test for host...

Laboratory experiments tested whether two economically-important sibling species of tephritid fruit flies have evolved distinct egg-laying responses to chemical stimuli on the fruits of their respective hostplants. The egg-laying preferences displayed by apple maggot flies, R. pomonella, and blueberry maggot flies, R. mendax, on artificial fruits treated with apple and blueberry extract paralle...

Host shifts of phytophagous insect specialists to novel plants can result in divergent ecological adaptation, generating reproductive isolation and potentially new species. Rhagoletis pomonella fruit flies in eastern North America underwent a host shift ~160 ya from native downy hawthorn (Crataegus mollis) to introduced, domesticated apple (Malus domestica). Divergent selection on diapause phen...