The Effect of Growth and Development of Biston suppressaria Fed on Different Host Plants

Biston suppressaria(Guenée) is a significant foliar pest affecting Eucalyptus spp. in China. Given that Eucalyptus is not a native host of B. suppressaria, this study aims to explore the mechanisms underlying the adaptation of B. suppressaria to Eucalyptus and the effects of feeding on different hosts on the growth and development of B. suppressaria, providing insights into the pest's outbreak mechanisms within these areas. Four species of host plants(Vernicia fordii, Camellia oleifera, Sapium sebiferum and Eucalyptus urophylla × E. grandis) were selected to feed on B. suppressaria and measure and calculate indicators such as their developmental duration, pupal weight, survival rate, pupation rate and emergence rate. B. suppressaria larvae successfully completed pupate and emerge fed on E. urophylla × E. grandis, V. fordii and S. sebiferum, while they were largely unable to do so on C. oleifera. The survival rate, pupation rate, and emergence rate of larvae fed on E. urophylla × E. grandis were 80%, 85%, and 96.5%, respectively; for V. fordii, they were 70%, 82.5%, and 90.75%, respectively; and for S. sebiferum, they were 80%, 82.5%, and 93.75%, respectively. In contrast, the survival rate, pupation rate, and emergence rate of larvae fed on C. oleifera were 5%, 10%, and 41.65%, significantly lower compared to those fed on the other three hosts. The average development duration of larvae fed on E. urophylla × E. grandis was 27.06 days, significantly longer than that on V. fordii(22.37 days) and S. sebiferum(23.13 days), with peak larvae weight observed at day 20 for E. urophylla × E. grandis and at day 14 for S. sebiferum. The pupal weight of larvae fed on E. urophylla × E. grandis was 0.57 g, significantly lower than that of larvae fed on V. fordii(0.93 g) and S. sebiferum(0.91 g). Additionally, the relative growth rate(0.087), food utilization rate(20.29%), and nutrient conversion rate(46.56%) of larvae fed on E. urophylla × E. grandis were also significantly lower compared to those fed on V. fordii and S. sebiferum. Although the relative growth rate, food utilization rate, pupation rate, and pupal weight of B. suppressaria larvae fed on E. urophylla × E. grandis were lower than those on V. fordii and S. sebiferum, they were still able to complete pupate and emerge. Furthermore, there was no significant difference in the pupation rates and emergence rates among the above three host plants. This suggests that B. suppressaria may be gradually adapting to feeding on Eucalyptus. As the area of Eucalyptus plantations continues to expand, the potential for increased damage from this pest is likely to escalate in the future.