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Volatile chemicals produced by plants mediate host location, mate-finding and oviposition behavior in insects. State-dependent response to plant cues allows for timing of foraging, mating and oviposition on ephemeral host plants or plant parts. Caloptilia fraxinella is a herbivorous specialist on the foliage of ash trees (Fraxinus). Adults are long-lived and undergo a nine-month reproductive diapause over the fall and winter. Mating and oviposition occur in the spring when volatile chemicals released by ash leaves mediate host location. This study tested the plasticity of olfactory response of C. fraxinella to host plant volatiles using both electroantennogram and behavioral bioassays. The effect of moth physiological state on olfactory response was tested on male and female moths in different nutritional, mating, and diapause states. Antennal responses to host plant volatiles were plastic and depended on moth physiological state, and were highest when moths were reproductively active and would be seeking oviposition hosts. Moth sex and nutritional status also impacted antennal response to host plant volatiles. Oriented flight of females to ash seedlings varied with physiological state and nutritional status, with fed, reproductively active females having the highest response. Physiological state impacted oriented flight of males to female-produced sex pheromone signals whether or not a host plant was present, and there was no increase in behavioral response to sex pheromone in the presence of an ash host. [ABSTRACT FROM AUTHOR]

Quinoa, Chenopodium quinoa Willdenow (Amaranthaceae), cultivation has expanded beyond its historical range in South America into Europe and North America due to its high nutritional properties for human consumption. With the introduction of a crop into a novel range comes the potential for insect pest issues. Here, using traditional morphology and DNA barcoding we identify larvae of Scrobipalpa atriplicella (von Röslerstamm) (Lepidoptera: Gelechiidae), an introduced Eurasian moth, feeding on quinoa throughout the Prairie region of western Canada. Larvae can feed within the stem, on foliage, and directly on seed within the panicles, which can result in up to a 100% yield loss. We summarise distinguishing adult characteristics, potential host plants, and give initial remarks on the life cycle of this moth and its known host range in Canada. The potential for high yield losses makes further investigation of S. atriplicella a priority to maintain and expand sustainable quinoa production in Canada. [ABSTRACT FROM AUTHOR]

The preference-performance or 'mother-knows-best' hypothesis states that female insects choose to oviposit on a host plant that increases the performance of their offspring. This positive link between host plant choice and larval performance is especially important for leaf miners with non-motile larvae that are entirely dependent upon the oviposition choice of the female for host plant location. Preference and performance of the ash leaf coneroller, Caloptilia fraxinella ( Ely) ( Lepidoptera: Gracillariidae), a specialist on ash trees, Fraxinus spp. ( Oleaceae), were tested in a series of laboratory and field experiments. Female C. fraxinella were exposed to two closely related hosts, black ash, Fraxinus nigra Marshall, and green ash, Fraxinus pennsylvanica Marshall var. subintegerrima ( Vahl), in oviposition choice and wind tunnel flight experiments to determine which host is most attractive for oviposition. Caloptilia fraxinella females were inconsistent in host choice, yet performance of larvae was greater on green than black ash. In preference studies, C. fraxinella preferred to oviposit on black ash when leaflets were removed from the tree, but preferred intact green ash over black ash seedlings for oviposition and host location in a wind tunnel. In the field, however, more C. fraxinella visited black ash var. 'Fallgold' at leaf flush than green ash at the same sites. Age of the ash leaflet also influences oviposition in this leaf miner and females preferred new over old leaflets for oviposition. Performance of C. fraxinella larvae was evaluated in field and laboratory experiments and was greater on green ash than on black ash in both experiments based on larval survival and development time parameters. The stronger oviposition and host location preference in the field for black ash were not linked to enhanced performance of offspring, as green ash was the superior host, supporting higher larval survival and faster development. A stronger host location preference in the wind tunnel for green ash over black ash, however, suggests that under certain circumstances with this moth species, 'mother (may) know best'. [ABSTRACT FROM AUTHOR]