Behavioral responses of leafroller larvae to apple leaves and fruit

Abstract

Larvae of Epiphyas postvittana and Planotortrix octo were released onto branches cut from apple trees, and allowed to colonize a range of types of artificial nests. Both species exhibited similar strong preferences for nests comprising leaf-leaf or leaf-fruitlet combinations, followed by nests comprising leaf-plastic leaf, leaf-plastic fruitlet or plastic leaf-fruitlet combinations. Nests involving fresh plant material alone (shoot, fruitlet or leaf alone) were also colonized to a lesser extent, but no larvae were found on nests consisting of plastic leaves or fruitlets alone or in combinations of the two. In another experiment, more E. postvittana larvae colonized nests with leaf and fruitlet combinations, compared to leaf and glass ball, or leaf and treated wax ball combinations, where the wax had been in contact with fresh apples or fruitlets. Choice tests, conducted using larval traps, showed that larvae were caught in traps baited with odors collected and released by wax which had been in contact with mature apples and leaves. Chloroform extracts from apple skin also caught larvae in choice tests. These results suggest that both physical and chemical cues are important to leafroller larval establishment.

Response to host plant odors and aggregation pheromone by larvae of the Colorado potato beetle on a servosphere

“…There are many other studies showing successful navigation by larvae to or toward the odor source in a diffusion gradient without airflow, but where behavioral details were not measured directly (Suckling and Ioriatti 1996;Khalifa et al 1973;Rembold et al 1989;Doane et al 1975;Paim and Beckel 1963;Mochizuki et al 1989;Singh and Mullick 2002). These studies involved phytophagous burrowing or surface feeders and the results could be explained by klinotaxis, arrestment or reduced straightness at increased stimulus concentration.…”

Effects of plant micro-environment on movement of Helicoverpa armigera (Hübner) larvae and the relationship to a hierarchy of stimuli

“…Plant-based odours have been implicated in micro-environmental choices of the light brown apple moth, Epiphyas postvittana. Here, larvae showed a preference for leaf-leaf or leaf fruitlet ''nests'', and odours from waxes of mature apples and leaves were important in establishment (MacLellan 1973;Suckling and Ioriatti 1996). Plant odours have been demonstrated to drive a loss of positive phototactic response in silk worms (Bombyx mori), where loss of response occurs after exposure to the volatiles from host plant leaves (Shimizu and Kato 1978).…”

“…Some lepidopteran larvae are often observed in confined spaces such as fruiting bodies, leaves that provide covered areas, or stems (MacLellan 1973;Suckling and Ioriatti 1996). In the case of the stem borers, Sesamia calamistis (Lepidoptera: Noctuidae) and Eldana saccharina (Lepidoptera: Pyralidae), this behaviour was interpreted as an active defense strategy against parasitism by braconid parasitoids (Potting et al 1999).…”

Caterpillar-induced plant volatiles attract conspecific adults in nature

“…Because of the economic importance of apple as an internationally-traded commodity, apple volatiles have been extensively examined, particularly in the context of insect behaviour of codling moth, Cydia pomonella (Linnaeus), apple maggot, Rhagoletis pomonella (Walsh), and apple sawfly, Hoplocampa testudinea (Klug)202122232425. Seasonal patterns of the release of volatiles from mature apple trees have also been investigated in studies of codling moth and apple fruit attack2627. Quantitative and qualitative differences in volatile profiles between apple seedlings infested with LBAM larvae and healthy apple seedlings were recently reported28.…”