The guava fruit fly, Bactrocera correcta, is one of the most destructive pests in the genus Bactrocera and detects environmental odorants mainly through antennal olfactory sensilla phenotypes with nanopores. However, it is unclear whether there are naturally occurring abnormal antennal olfactory sensilla phenotypes that affect olfaction. Here, we found that there were abnormal bulges besides nanopores on the surface of trichoid and basiconic olfactory sensilla in the antennal flagellum of long-term laboratory rearing colony (LTC), and that nanopore number in these olfactory sensilla was also remarkably reduced. Notably, the electroantennogram (EAG) responses of LTC insects to methyl eugenol or β-caryophyllene were inhibited, and their behavioral responses elicited by the same odorants were also impaired. These results revealed naturally occurring abnormal antennal olfactory sensilla phenotypes which were involved in olfactory deficit in B. correcta, providing a platform to further study nanopore-targeted pest control technologies in the future.

In this study, changes in physiological characteristics of Coridius chinensis (Hemiptera: Dinidoridae) during diapause and post-diapause development period were determined. The moisture content of C. chinensis at the beginning of diapause was significantly lower than that at any other stage, and the moisture content during post-diapause development period was significantly higher than that from October to December 2021 and in February and April of the following year. The fat content gradually declined over time. The glycogen content remained at lower levels during diapause but rose sharply during the post-diapause development period, when it became significantly higher than that during diapause. The trehalose content gradually declined in the early stages of diapause but rose greatly in the middle stage, followed by a gradual decline in the late stages and a significant increase during the post-diapause development period. The protein content was at lower levels in the early stages of diapause, significantly lower than that in the middle and late stages of diapause and that during post-diapause development period. The results indicated significant differences in changes in the moisture, fat, carbohydrate, and protein contents between the diapause and post-diapause development periods, with obvious stage characteristics. This study provides a scientific basis for further research on the diapause physiology of C. chinensis.

The present study assessed the effects of photoperiod and temperature on the development and survival rate of the predatory insect Eocanthecona furcellata under various photothermal gradients in climate-controlled chambers. The eggs of E. furcellata did not hatch at 15°C and exhibited the lowest hatching rate at 35°C, with only 28.0% and 13.0% hatching rates under long and short photoperiods, respectively. Moreover, the nymphs hatched under the conditions mentioned above did not survive. Linear regression analysis identified 17.7°C as the developmental threshold temperature for eggs, with an effective accumulated temperature of 62.3 °C. The developmental threshold temperature for nymphs was 17.0°C, with an effective accumulated temperature of 167.3 °C. These findings indicate that temperature exerts a significant impact on the developmental rate of E. furcellata during early stages unlike photoperiod. Under both long and short photoperiods, the eggs exhibited high hatching rates, while nymphs demonstrated the highest survival rates at 25°C. Further analysis with the Weibull distribution function showed that the survival rate curves for the insect at the early stages fitted Type I category, indicating that mortality rate increased over time. Thus, we recommend rearing eggs under short photoperiod conditions and nymphs under long photoperiod conditions, maintaining the temperature of the growth chamber at 25°C.

The hatching rates and developmental durations of Eupolyphaga sinensis Walker eggs were studied under variable combinations of low temperatures (5 °C and 10 °C) and high temperatures (25 °C and 30 °C). Our findings were intended to provide new evidence on the effect of temperature on the hatching of insect eggs. The results showed that both low temperatures and high temperatures significantly affected the hatching rate and time of E. sinensis eggs. Further analysis revealed a significant interactive effect between low temperatures and high temperatures. The 5 °C + 30 °C treatment achieved the highest egg hatching rate (77.33%) and the shortest hatching time (44.11 ± 1.55 d), which was significant compared with three other temperature treatments. The effects of high temperatures treatments on the hatching rate and the hatching time were more significant than that in the low temperature treatments. Hatching began earlier at 5 °C + 30 °C and 10 °C+30 °C temperatures, and single-day hatching first increased rapidly before declining afterwards within a short period. Comparatively, the hatching of eggs under the (5 °C+25 °C) and (10 °C+25 °C) temperatures was initially significantly delayed, including the peak single-day hatching rate. Under these treatments, the hatching rate tended to be gradual in terms of the temporal dynamics without showing any prominent peak. These results showed that low and high temperatures significantly affect the hatching rates of E. sinensis eggs. This study provided basis for the large-scale breeding of E. sinensis.