Specialization and accuracy of host-searching butterflies in complex and simple environments

No Effect of Early Adult Experience on the Development of Individual Specialization in Host-Searching Cabbage White Butterflies

“…First, according to the preference-performance hypothesis, ovipositing female insects should be more likely to lay eggs on host plants that are most suitable for larval development (review [46]). However, at least for the growing conditions in these experiments, cabbage white larvae develop at a faster rate on radish than on cabbage, indicating that the butterflies did not preferentially visit cabbage because of its higher nutritional quality [40]. Alternatively, cabbage white butterflies could have a genetically based population-level preference for cabbage because the host maximizes some other element of larval survival (e.g., enemy-free space, disease resistance, reduced competition) or has been a reliable host over many generations.…”

“…To rear these experimental individuals, wild-caught females were placed inside a mesh 60 × 60 × 60 cm "bug dorm" and allowed to lay eggs on store-bought organic cabbage leaves with a non-host plant for humidity and a sponge soaked in 10% honey water for food. Leaves with eggs were transferred to a climate chamber (23 degrees Celsius, 14L:10D, 60% relative humidity) and, after 7 days, early second instar caterpillars were transferred to artificial diet [40]. Caterpillars remained in the climate chamber on artificial diet until they emerged as adults.…”

“…Tarsal drumming on a host plant is usually followed by "oviposition" which was scored separately from "landing" because the former is a pre-alighting choice (largely visual) and the latter, a post-alighting choice (largely tactile). The likelihood that butterflies will oviposit on a host plant after landing on it ("acceptance rate") is similar for both radish and cabbage [40]. The observer continuously recorded landings and ovipositions, the species of plant each behavior was associated with, and the time they occurred using the software, Jwatcher, on a laptop computer [42].…”

“…Cabbage whites are a good model to explore the effects of early adult experience on host choice because associative learning plays a role in host searching, with individuals remembering color cues over multiple days [24,37,38]. Cabbage whites often show individual variation in host plant and floral preferences [39,40] and they are experimentally tractable in terms of controlled lab rearing and adult behavioral observations [40,41]. Given that these butterflies use associative learning to discriminate host plants from non-host plants, we predicted that the butterflies would learn the cues associated with the most abundant host in their early environment and retain those cues on their second day of foraging, preferentially landing on that host over others.…”

Spatial scale, neighbouring plants and variation in plant volatiles interactively determine the strength of host–parasitoid relationships

“…For example, plant variation in chemical resistance can affect immune responses of herbivores to their parasitoids (Bukovinszky et al 2009, Smilanich et al 2009 and plant variation in the emission and chemical composition of herbivore-induced plant volatiles (HIPVs) that are used by parasitoids to locate their host can affect local parasitoid abundance (Vet and Dicke 1992, Beyaert and Hilker 2014, Turlings and Erb 2018. Because parasitoids and herbivores may respond to different cues (Steck andSnell-Rood 2018, Aartsma et al 2019b), variation in plant traits may affect herbivores and parasitoids differentially and cause spatial variation in the strength of trophic interactions.…”