Increased per-capita investment in egg production by female apple snails in the presence of predatory common carp

We hypothesized that apple snails would change life-history traits in the presence of common carp to reduce or avoid predation risk. Carp of about 150 mm body length were released in small plots set in a rice field in southern Japan at 0, 0.2, or 0.6 carp/m2. Egg-mass size, proportion of hatched eggs, and duration of hatching of the snail were measured once or twice a week from July to September. Snails collected in traps were used to estimate both snail density by the Jolly-Seber mark-recapture method and distribution of shell lengths in each plot. The weight of the snail was regressed on a size-weight equation, and the snail biomass was determined by multiplying the estimated density and the regressed weight. The reproductive effort of the snails was calculated as the number of eggs divided by the biomass of adult females. The egg mass size and reproductive effort were significantly increased in the presence of carp. These increases were considered as life-history changes of apple snails in the presence of a predator.

Population Biology of Orangestriped Oakworm (Lepidoptera: Saturniidae) in Southeastern Virginia

Population biology of orangestriped oakworm, Anisota senatoria (J. E. Smith), was studied in southeastern Virginia. Egg mass size was larger on Quercus palustris Muench., pin oak, compared with Q. phellos L., willow oak. Females produced a sex pheromone that attracted male moths. Blacklight traps were not effective for monitoring A. senatoria adults. Peak male emergence occurred on 2 July, 4 days earlier than female. The mean life span was 33.5 days in the laboratory. Pupal mortality was high and only 1.2% of the pupae produced moths in 1989 and 1990. Pupae were capable of overwintering for two years in the field. The first report of a second generation from September - November was documented. Second generation A. senatoria oviposited more egg masses, infested more trees and had a longer development time compared with first generation. Large egg mass size, pupae that were capable of overwintering for two years and the presence of a second generation may partially explain the consistent A. senatoria populations that have occurred in southeastern Virginia.

Site Selection for Oviposition and Larval Feeding by the Tufted Apple Bud Moth (Lepidoptera: Tortricidae) on Apple in Pennsylvania

Intensive sampling was used to characterize the size and leaf type for tufted apple bud moth, Platynota idaeusalis (Walker), egg mass deposition, and to determine the association and site of larval feeding on fruit and foliage in Pennsylvania apple orchards. Results suggest tufted apple bud moth prefer to oviposit on smaller leaves (<20 cm2), and egg mass size was 0.16 cm2 during first brood and 0.12 cm2 during second brood. Significantly more first and second brood egg masses were oviposited on leaves within nonfruiting spurs than on either vegetative shoots or fruiting spurs. Both larval broods were found in association with leaves only rather than leaves and fruit. Fruit injury due to larval feeding during both broods occurred more on the calyx (sepals) surface area than the side or stem surface areas of the fruit. In cultivar comparisons of fruit, more surface injury was located on the site of the fruit from ‘Stayman’ trees than for ‘Golden Delicious’ trees.