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For investigating the physiological responses of herbivores to the heavy metal-stressed woody host plants, the activities of antioxidant, detoxifying, and digestive enzymes in the gypsy moth larvae, Lymantria dispar, that were fed with different heavy metal-stressed poplar seedling (Populus alba berolinensis) leaves were studied. The heavy metal treatments included Cd-treated pot soil (1.5 mg/kg), Zn-treated pot soil (500 mg/kg), and Pb-treated pot soil (500 mg/kg), plus an untreated pot soil as the control. Our results showed that compared with the untreated control, superoxide dismutase (SOD) and catalase (CAT) activities in Cd or Zn treatment group were gradually suppressed with the increases of larval ages, but Pb treatment had no significant effects on SOD activities and significantly increased the CAT activities in both fourth and fifth instar larvae; acid phosphatase (ACP) activities were gradually activated and alkaline phosphatase (AKP) activities were gradually inhibited with the increases of larval ages in Cd or Pb treatment group, but Zn treatment significantly increased the activities of ACP and AKP both in fourth and in fifth instar larvae. All three heavy metals tested did not show any significant effects on the amylase and protease activity in the fourth instar larvae but increased their activities in fifth instar larvae. These results suggest that antioxidant, detoxifying, and digestive enzymes constituted the basic defense system for gypsy moth larvae to resist the toxicity originated from the accumulated Cd, Zn, or Pb in poplar leaves, but their defense level varied with metals investigated and larval developmental stages.

Heavy metal contaminations have attracted increasing concern worldwide due to their potential damages to the whole ecosystem. This study investigated the heavy metal-accumulation and excretion in, and food utilization of the gypsy moth (Lymantria dispar) larvae that were fed with leaves plucked from poplar seedlings (Populus alba berolinensis) grown in either noncontaminated soil (control), Zn-contaminated soil (500mg/kg), or Pb-contaminated soil (500mg/kg). Our results showed that excretion of heavy metals via insect feces and exuvia is an effective approach to reduce the internal Zn and Pb concentrations, and result in the decrease of Zn and Pb concentrations in the gypsy moth larvae with the increased larval age. In addition, the gypsy moth larvae seemed to have a strong homeostatic adjustment mechanism [between approximate digestibility (AD) and efficiency of conversion of digested food (ECD)] that maintains a stable level of "efficiency of conversion of ingested food (ECI)" regardless of heavy metal (Zn or Pb) contaminations or not, except the fifth instar larvae in which the increase in AD was insufficient to compensate for the decrease of ECD. These results suggest that heavy metal excretions could help the gypsy moth larvae cope with Zn or Pb stress, and the increased digestion of food could meet their energy requirements for both detoxification and growth. However, further increase in Zn or Pb exposure time seemed to inhibit the larval food utilization.

Native to China and Korea, the Asian longhorned beetle, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae), is a polyphagous wood-boring pest for which a trapping system would greatly benefit eradication and management programs in both the introduced and native ranges. Over two field seasons, a total of 160 flight intercept panel traps were deployed in Harbin, China, which trapped a total of 65 beetles. In 2012, traps using lures with a 1:1 ratio of the male-produced pheromone components (4-(n-heptyloxy)butanal and 4-(n-heptyloxy)butan-1-ol) designed to release at a rate of 1 or 4 milligram per day per component in conjunction with the plant volatiles (-)-linalool, trans-caryophyllene, and (Z)-3-hexen-1-ol caught significantly more A. glabripennis females than other pheromone release rates, other pheromone ratios, plant volatiles only, and no lure controls. Males were caught primarily in traps baited with plant volatiles only. In 2013, 10× higher release rates of these plant volatiles were tested, and linalool oxide was evaluated as a fourth plant volatile in combination with a 1:1 ratio of the male-produced pheromone components emitted at a rate of 2 milligram per day per component. Significantly more females were trapped using the pheromone with the 10-fold higher three or four plant volatile release rates compared with the plant volatiles only, low four plant volatile + pheromone, and control. Our findings show that the male-produced pheromone in combination with plant volatiles can be used to detect A. glabripennis. Results also indicate that emitters should be monitored during the field season, as release rates fluctuate with environmental conditions and can be strongly influenced by formulation additives.