Offspring performance and female preference of Pagiophloeus tsushimanus (coleoptera: curculionidae) on three Lauraceae tree species: A potential risk of host shift caused by larval experience

Abstract

The weevil Pagiophloeus tsushimanus Morimoto (Coleoptera: Curculionidae), native to Eastern Asia, is a wood‐boring pest that causes severe damage to camphor trees (Cinnamomum sp.) in Shanghai, China. Other Lauraceae tree species that grew sympatrically with this pest in close proximity could face a potential threat. To assess the potential risks of host shift, we explored the phenotypic associations between preference and performance in P. tsushimanus reared on three Lauraceae tree species. In a no‐choice experiment offering branches of each plant as diet material and oviposition sites, we found that individuals reared on Cinnamomum camphora (L.) Presl (Laurales: Lauraceae) exhibited the strongest performance with shorter development time, higher survival and growth rate in the immature stage, longer longevity and greater fecundity in adults. In contrast, those on novel Lauraceae tree species (Cinnamomum chekiangensis Nakai and Phoebe chekiangensis Shang) had difficulty completing their whole life cycle due to significantly lower survival and reproduction. In a multiple‐choice experiment, C. camphora was established as the preferred host. However, we found that the larval experiences on the non‐preferred host plants contributed to an increased preference for that plant species. These results indicated that both the preference‐performance hypothesis and the Hopkins’ host selection principle are applicable in this weevil under experimental conditions. It is possible that although the weevil performed poorly on two novel Lauraceae tree species, under favourable conditions their surviving offspring could evolve into a new host‐specific population. Consequently, this weevil pest needs to be monitored on these novel Lauraceae tree species.

Tolerance to dietary linalool primarily involves co-expression of cytochrome P450s and cuticular proteins in Pagiophloeus tsushimanus (Coleoptera: Curculionidae) larvae using SMRT sequencing and RNA-seq

“…A laboratory colony of Pagiophloeus tsushimanus was established from adults in Cinnamomum camphora plantations in Songjiang district, Shanghai city, China (30°56′6.15″N, 121°12′32.76″E) in May 2021. A complete breeding system for P. tsushimanus in the laboratory was described in our previous study [25]. In brief, the adults were allowed to feed, mate randomly and oviposit on fresh branches of camphor tree in a plastic cage.…”

“…More recently, an emerging insect pest, Pagiophloeus tsushimanus (Coleoptera: Curculionidae) has been found to persist exclusively on camphor trees, and locally cause serious damage in China [24,25]. It evokes our great interest that how this insect pest tolerates host-specific terpenoid defenses from camphor trees without incurring apparent fitness costs.…”

Hormetic response and transcriptome profiling reveal the mechanism underlying metabolic and cuticular resistance to host-specific terpenoid defences in an emerging insect pest, Pagiophloeus tsushimanus (Coleoptera: Curculionidae)

“…Pagiophloeus tsushimanus was obtained from a culture established at the Entomology Biological Laboratory, Nanjing Forestry University (EBL, NJFU), Jiangsu Province, China, in 2019 and originally collected from C. camphora plantations in Songjiang District, Shanghai Province, China (30°56′6.15″N, 121°12′32.76″E). The breeding system applied to P. tsushimanus eggs, larvae, pupae and adults was described in our previous study (Li et al, 2021). In brief, eggs were deposited in a Petri dish (5 cm i.d.…”

“…Nevertheless, only a handful of models for insect-plant interactions offered unbiased transcriptional pro les related to host plant adaptations in herbivorous insects, and few studies have revealed these two resistance mechanisms simultaneously in the same experimental model. The insect pest Pagiophloeus tsushimanus (Morimoto) is a trunk-boring specialist herbivore with only camphor trees as its preferred host in natural environments (Chen et al, 2020;Li et al, 2021). Since this weevil was reported in 2014, it has rapidly reached epidemic levels in Shanghai, China.…”

“…The camphor tree Cinnamomum camphora (L.) Presl (Laurales: Lauraceae), has been widely exploited as a shade tree or as industrial material in several countries, and it is less likely to be vulnerable to various herbivorous insects because of its speci c terpenoid defences (e.g. a class of monoterpene-derived metabolites such as Dcamphor) (Li et al, 2021). Thus, it would be interesting to explore how this pest could mount an e cient counter-defence response.…”