Preference Provides a Plethora of Problems (Don't Panic)

This review was solicited as an autobiography. The “problems” in my title have two meanings. First, they were professional difficulties caused by my decision to study oviposition preferences of butterflies that were not susceptible to traditional preference-testing designs. Until I provided video, my claim that the butterflies duplicate natural post-alighting host-assessment behavior when placed on hosts by hand was not credible, and the preference-testing technique that I had developed elicited skepticism, anger, and derision. The second meaning of “problems” is scientific. Insect preference comes with complex dimensionality that interacts with host acceptability. Part Two of this review describes how my group's work in this area has revealed unexpected axes of variation in plant–insect interactions—axes capable of frustrating attempts to derive unequivocal conclusions from apparently sensible experimental designs. The possibility that these complexities are lurking should be kept in mind as preference and performance experiments are devised.

Ozone-Induced Acceptability of Yellow-Poplar and Black Cherry to Gypsy Moth Larvae

The feeding behavior of 3rd instar gypsy moth (Lymantria dispar L. [Lepidoptera: Lymantriidae]) was examined on foliage from black cherry (Prunus seratina L.) and yellow-poplar (Liriadendran tulipifera L.) seedlings exposed to 71 ± 31, 212 ± 37, and 337 ± 31 μg m−3 ozone (O3) for 70 hours to gauge the effect of O3 stress on host acceptability. Normally, black cherry is a suboptimal food source and yellow-poplar is unacceptable. With feeding preference assays conducted in the laboratory using feeding arenas, the leaf area consumption of black cherry control foliage (exposed to ambient air containing 71 μg m−3 O3) by starved larvae was approximately twice that of yellow-poplar control foliage during the first 4 hours. By 8 hours, the leaf area consumed was the same for both species. O3-treated leaves of both species were preferred by the larvae relative to leaves exposed to ambient concentrations. The effect was pronounced for yellow-poplar, where consumption of ozonated foliage was more than twice that of the control, and its acceptability was enhanced to a level approximating that of black cherry.

INFLUENCE OF HOST AGE ON HOST ACCEPTABILITY AND SUITABILITY FOR A SPECIES OF TRICHOGRAMMA (HYMENOPTERA: TRICHOGRAMMATIDAE) ATTACKING AQUATIC DIPTERA

Eggs of Sepedon fuscipennis (Diptera: Sciomyzidae) < 1, 1–2, 2–3, and 3–4 days old were offered to inexperienced female Trichogramma sp. near californicum in a laboratory experiment. Exposure period (2 h) and number of host eggs offered at one time (10) were held constant. Percentage of hosts parasitized, total number of parasitoid progeny found in a group of hosts, percentage of parasitized hosts yielding adult parasitoids, and survivorship of parasitoid progeny to adulthood all decreased significantly with increased host age. Younger hosts yielded more than one adult parasitoid more often than did older hosts. Over 50% of the adult parasitoids emerging from hosts < 1, or 1–2 days old were female. Hosts 2–3 days old produced only males. The data show a somewhat different relationship of host age to host acceptance and suitability than do some published data on lepidopteran hosts of Trichogramma.