Carbon dioxide (CO₂) released by plants can serve as a cue for regulating insect behaviors. Hyphantria cunea is a widely distributed forestry pest that may use CO₂ as a cue for foraging and oviposition. However, the molecular mechanism underlying its ability to sense CO₂ has not been elucidated. Our initial study showed that CO₂ is significantly attractive to H. cunea adults. Subsequently, 44 H. cunea gustatory receptors (GRs) were identified using transcriptome data, and 3 candidate CO₂ receptors that are specifically expressed in the labial palps were identified. In vivo electrophysiological assays revealed that the labial palp is the primary organ for CO₂ perception in H. cunea, which is similar to findings in other lepidopteran species. By using the Xenopus oocyte expression system, we showed that the HcunGR1 and HcunGR3 co-expressions produced a robust response to CO₂, but HcunGR2 had an inhibitory effect on CO₂ perception. Finally, immunohistochemical staining revealed sexual dimorphism in the CO₂-sensitive labial pit organ glomerulus (LPOG). Taken together, our results clarified the mechanism by which H. cunea sense CO₂, laying the foundation for further investigations into the role of CO₂ in the rapid spread of H. cunea.

Bumblebees are important pollinating insects in crop pollination. Chemical attractants can effectively improve the flower-visiting efficiency of bumblebees, thereby increasing blueberry yields. To identify volatile compounds that attract bumblebees, we collected volatile compounds from blueberry flowers using headspace extraction. Gas chromatography– mass spectrometry (GC–MS) identified 32 volatile compounds, with Linalool and Styrene being the primary substances that accounted for 25.93% and 14.28%, respectively. The olfactory threshold of bumblebee antennae was assessed using electroantennography (EAG), and the behavioral responses from bumblebees were investigated using a Y-tube olfactometer. Results indicate that among the six classes of volatiles—alcohols, aldehydes, esters, ketones, aromatic compounds, and olefins—alcohols constituted the predominant proportion. Among these, six compounds—benzaldehyde, phenylpropylaldehyde, citral, linalool, α-terpineol, and geraniol—induced significant antennal responses in bumblebees. Our assays showed that geraniol, linalool, and α-terpineol at concentrations of 0.1 μg/μL, 1 μg/μL, and 10 μg/μL elicited attraction, whereas higher concentrations of benzaldehyde, benzenepropanal, and citral had repellent effects.

During the cultivation of Taxus cuspidata, significant differences in leaf coloration between different types have emerged, which is of great significance for variety breeding. This study employed transcriptomic and metabolomic analyzes to identify key genes and metabolites associated with leaf color variation between the yellow leaf type and the green leaf type. The results showed: (1) Metabolites such as kaempferol 3-p-coumaroylglucoside, quercetin-3’-glucuronide, kaempferol-3-O-rutinoside, Ridiculuflavone D, phaeophorbide b, and paclitaxel were significantly higher in the yellow leaf type compared to the green leaf type, while the content of tetrapyrrole compounds was significantly lower in the yellow leaf type.(2) Transcriptomic analysis indicated that genes involved in carotenoid synthesis, flavonoid synthesis, and chlorophyll degradation, such as F3H, FLS, ZEP, PSY, and FLN, were significantly upregulated in the yellow leaf type compared to the green leaf type. In contrast, genes involved in chlorophyll biosynthesis (GLK, SGR) and anthocyanin synthesis (DFR) were significantly downregulated. qRT-PCR analysis further validated these results. (3) Integrative transcriptomic and metabolomic analysis revealed significant positive correlations between F3H, FLS, FLN genes and flavonoid compounds, and between GLK, SGR genes and the reduction in tetrapyrrole compounds, promoting chlorophyll and chloroplast degradation. These findings suggest that the acquisition of yellow leaf traits in Taxus cuspidata is mainly achieved by enhancing upstream flavonoid biosynthesis pathways and downstream chlorophyll degradation pathways, including phenylpropanoid biosynthesis, flavonoid biosynthesis, and chlorophyll degradation, while limiting the downstream anthocyanin biosynthesis pathway and related processes.

Previous studies have shown that the threat level posed by a predator can vary with physical features. In this study, we tested whether the wing posture of a raptor could serve as a clue for bird threat assessment. We observed the behavioral response of Japanese tits Parus minor to taxidermy dummies Eurasian sparrowhawks Accipiter nisus with either spread wings and closed wings. The results showed that the response scores to sparrowhawks with spread wings were higher than those to sparrowhawks with closed wings. We suggested that Japanese tits can assess the predation risk associated with changes in wing posture of predators.

Heavy metals in soil can be translocated to floral rewards via specific physiological pathways, potentially altering pollinator behavior and reducing plant reproductive fitness. However, the comparative effects of different heavy metals on floral rewards and pollination remain poorly understood. Here, blueberries were used as a model system to examine the accumulation of four heavy metals (Zn, Pb, Cu, and Ni) in floral rewards and assess their impacts on plant reproductive performance and bumblebee visitation behavior under controlled conditions. Heavy metals accumulated in floral rewards in a concentration-dependent manner, with strong positive relation to soil metal levels; pollen generally contained higher concentrations than nectar. Increasing soil heavy metal concentrations significantly shortened bumblebee visit duration to individual flowers, with the greatest reduction under high Pb treatment (26.32%), followed by Zn (21.49%), Ni (17.70%), and Cu (15.40%). Visit frequency also declined under medium to high concentrations. All heavy metal treatments reduced pollen viability (1.62–24.48%), pollen deposition on stigmas (9.91–40.59%), and single-fruit weight (16.25–32.51%), with effect magnitudes varying by metal (generally Pb > Cu > Zn > Ni). Overall, heavy metal accumulation in floral rewards negatively affects pollinator behavior and compromises plant reproductive fitness, with metal-specific effect strengths.

Diurnal and nocturnal raptors exhibit significant differences in foraging times and predatory behavior, yet little is known about the nesting defense responses of parent birds to these raptors during the breeding season. We observed the behavioral response of Japanese tits Parus minor to taxidermy dummies of Eurasian sparrowhawks Accipiter nisus and Indian scops owls Otus bakkamoena . Our results show that the nest defense intensity of Japanese tits against sparrowhawks is significantly lower than that against owls. Specifically, Japanese tits predominantly engage in distant observation behavior when encountering sparrowhawks, whereas they display more aggressive behavior toward owls. Overall, we propose that Japanese tits discriminate between sparrowhawks and owls, with the latter posing a lesser threat to adult birds.