High mixing ratios of ground-level O threaten trophic interactions. In the present study, we conducted laboratory assays, where insect larvae and adults were not directly exposed to O, to test the feeding behavior and attraction of the coleopteran leaf beetle Agelastica coerulea to early and late leaves of Japanese white birch (Betula platyphylla var. japonica) treated with ambient or elevated O levels. We found that overwintered adults were not deterred from grazing elevated O-treated leaves, but rather preferred them than ambient O-treated ones. We also found that the feeding behavior of 2nd instar larvae fed on early or late leaves was not influenced by the O treatment of the leaves when larvae could choose leaves. These observations of the adults and larvae feeding preferences contradict prior observations in the field conditions where the insects avoided leaves in O-enriched atmosphere. Since adults preferred elevated O-exposed leaves in the present laboratory assays, it is worthy of further investigations whether adults change their grazing preference so as to ensure the leaf palatability as a feeding source for their larvae. Hence, new direction towards detailed ovipositional behavior surveys under field conditions is encouraged.

A series of laboratory no-choice assays were performed to test changes in the feeding, growth, and nutrition of leaf beetle (Agelastica coerulea) larval instars on O-treated leaves of Japanese white birch (Betula platyphylla var. japonica). Larvae fed with O-treated leaves grew and developed significantly faster throughout their developmental cycle than the corresponding controls. The growth rate (GR) and consumption index (CI) were mostly decreased with age for both control and O-treated leaves. Efficiency of conversion of both ingested and digested food (ECI, ECD) showed an increase from the 2nd to the 4th instar, after which they decreased significantly and reached the lowest value in the last larval instars (7th). GR, CI, ECI, and ECD were greater and approximate digestibility (AD) was lower in larvae fed with O-treated leaves than those fed with control leaves. This indicated that the greater rate of growth on fumigated leaves was due primarily to a greater rate of consumption (i.e., O increased the "acceptability" of the host more than "suitability") and efficiency in converting food into body mass. Overall, larval performance seemed to have improved when fed with O-treated leaves in these assays. This study suggests that insects may be more injurious to O-treated plants and warrants further investigations on birch-beetle interactions under field conditions.

Tropospheric ozone (O 3) is a naturally occurring gas in the atmosphere. However, the concentration of O 3 increased in the 20 th century. Although the effects of O 3 on vegetation have been extensively studied since the 1950s, limited information exists regarding the effects of O 3 on insect herbivores. In particular, evidence is lacking regarding the effects of O 3 on the biology of insect herbivores. Agelastica coerulea (Baly, 1874) is a coleopteran species that grazes on Betulaceae plants. In this study, to investigate the effects of O 3 on A. coerulea biology for the first time, female adult insects were collected from Japanese white birch trees grown in a Free Air Controlled Exposure System (FACE) in Sapporo, Japan. These beetles inhabited trees exposed either to ambient or to elevated O 3 for 23 days. After 2 collection, the enzyme activities in the beetles were measured. Elevated O 3 led to a greater total antioxidant activity and lower α-and β-esterase activities, a phenomenon that may suggest an increased resistance of the beetles to stress. Our results are further discussed with regard to biological and toxicological aspects. Collectively, our findings indicate that total antioxidants and α-and β-esterase activities can serve as effective O 3 biomarker systems in this beetle species. This adaptive response of the beetle, which was induced by moderate O 3 exposure, should be further tested across generations and for its protection against greater exposure.

The effect of enriched CO 2 environments on natural plant-insect herbivore interactions is under attention. To understand such effects on insect growth and consumption, early and late instar larvae of the cotton leaf worm, Spodoptera littoralis (Lepidoptera: Noctuidae) reared on the cotton plant leaves Gossypium barbadens (Malvacae) grown under either ambient (350 PPM) or high (700 PPM) CO 2 atmospheres. Despite consuming more foliage, the mean larval fresh weight of the early (2nd) and late (4th) instar larvae increased insignificantly with age when fed cotton plant leaves from both ambient and enriched CO 2 regimes. Early and late Spodoptera littoralis larvae reared on high CO 2 -grown Gossypium barbadens consumed 32.87%, 44.98% respectively more foliage than larvae reared on low CO 2 -grown cotton plant. Larval duration for early and late larvae reared on high CO 2 -grown plants was longer compared with ambient treatments. The Consumption rate (CR) was decreased through the studied instars, with a high significant difference only between the 2nd instars. There was a tendency for ECI and ECD to decrease with age for larvae fed leaves from enriched CO 2 treatment. Differences in growth responses of early and late instar larvae to lower nitrogen and high-CO 2 grown foliage may be due to the inability of early instar larvae to efficiently process the increased flow of food through the gut caused by additional consumption of high CO 2 foliage. Under enriched CO 2 regime cotton plant shoot and root are significantly stimulate length, fresh and dry weights compared with ambient regime. С. А. Абу-Эльэля, В. М. Эльсаид. Влияние эффекта обогащенного СО 2 окуривания на взаимодействие растение-насекомое: питание и рост гусениц ранних и поздних возрастов египетской хлопковой совки Spodoptera littoralis (Lepidoptera: Noctuidae) // Дальневосточный энтомолог. 2018. N 351. С. 17-26.Резюме. Обсуждается влияние повышения концентрации углекислого газа на взаимодействие растений и растительноядных насекомых. Для этого гусеницы египетской хлопковой совки Spodoptera littoralis (Lepidoptera: Noctuidae) разводились на 17 листьях хлопчатника Gossypium barbadens (Malvacae), выращенных в атмосфере CO 2 при низком и высоком давлении (соответственно, 350 и 700 мм. рт. ст.). Гусеницы совки младших и старших возрастов потребляли листьев хлопчатника, выращенного при повышенной концентрации CO 2 , на 32.87% и 44.98% соответственно больше, по сравнению с выращенными при нормальном содержании углекислого газа растениями. Развитие гусениц младших и старших возрастов занимало больше времени при потреблении листьев растений, выращенных при повышенном содержании CO 2 . Норма потребления пищи (CR) уменьшалась у гусениц с возрастом, причем наиболее значительные различия отмечены у гусениц 2-го возраста. Отличия в росте гусениц ранних и поздних возрастов, питающихся выращенным при разной концентрации CO 2 хлопчатником, вероятно, обусловлено неспособностью гусениц младших возрастов эффективно переваривать листья кормового растения, выращенные при высоко...