Type and distribution of sensilla in the antennae of Euplatypus parallelus (F.) (Coleoptera: Curculionidea, Platypodinae).

Euplatypus parallelus (F.) (Coleoptera: Curculionidea) is the most destructive cosmopolitan insect pest of the Platypodinae. Pheromone-based luring agents are used currently in controlling bark beetle. Antennae are the primary insect organs sensing volatiles of host trees and pheromones of pioneer males. We studied the external morphology of antennae and the type, distribution, and the number of the beetle sensilla. Our results show E. parallelus have a geniculate antenna composed of 6 segments, namely the scape, 4-segmented funicle and club. Ninety-seven percent of the antennal sensors were distributed in the club, and 3% were distributed in the scape and funicle. 6 types of sensilla on the antennae were found, including sensilla trichodea (subtypes: STI, STII and STIII), sensilla basiconica (subtypes: SBI, SBII, SBIII and SBIV), sensilla chaetica (subtypes: SChI, SChII and SChIII), as well as sensilla coeloconica, sensilla campaniform and sensilla furcatea. There was no significant difference in the type, distribution and number of sensilla in males and females. No significant difference in the shape and distribution of antennae was found between sexes, but the length of antennae and the number of SChI, SChII, STI, SBI, SBIII and SBIV were significantly larger in females than males. We revealed the external cuticular structure of the antennae in E. parallelus, which can be used to guide future electrophysiological investigations to understand the ability of this beetle to detect semiochemicals

Influence of high-temperature exposure on the mating, oviposition and thermotaxis of Bactrocera cucurbitae (Coquillet) (Diptera:Tephritidae).

BACKGROUND:Bactrocera cucurbitae (Coquillett) is an important pest of cucurbit crops and certain vegetables in Asia, the Middle East, Africa and Hawaii. Most studies on B. cucurbitae have focussed on the effects of prolonged high temperature and very few have examined the effects of short-term exposures to high-temperature on behaviour. RESULTS:In this study, short-term of high-temperature treatments of 33°C, 37°C, 41°C and 45°C were maintained for 1-3hr, and long-term, variable high-temperature treatments were established that consisted of experienced one, two and three times high temperatures stages to 31°C, 33°C, 34°C, 35°C, 36°C, 37°C, 41°C and 45°C for 7hr. We compared the effects of the different high temperatures regimes changes treatments on the mating, oviposition and thermotactic taxis of the flies. The results showed that exposure to a 45°C/1hr treatment, delayed both initiation of mating and oviposition for 8 hr relative to the control but mating and was observed 41 times and oviposition 47 times. By comparison, in the control, mating commenced immediately and was observed 38.3 times and oviposition was observed 41.3 times. Under the other treatments, all the indices for the flies declined with the increase in temperature and duration of exposure. CONCLUSION:Results showed that 1hr of exposure to 45°C significantly stimulated mating, oviposition and thermotactic behaviour of the flies. These results could improve our understanding of the mechanisms responsible for the population dynamics of B. cucurbitae during the high-temperature season

Evaluation of endogenous reference genes in Bactrocera cucurbitae by qPCR under different conditions.

Bactrocera cucurbitae (melon flies) are prominent invasive pests in southern China. To screen for a stable reference gene in melon flies suitable for comparing tissue samples subjected to different conditions in four categories (temperature, insect stage, days of age and gender), the expression of 12 candidate reference genes under different treatment conditions was analyzed by real-time fluorescent quantitative PCR. The results obtained from a comprehensive analysis with geNorm, NormFinder, BestKeeper and RefFinder software showed that the most stable reference gene was RPL60, and the least stable reference gene was actin-5. We used a heat shock protein gene (HSP-90) to verify the results, and the conclusion was consistent. When the reference gene RPL60 was used as the reference gene, the relative expression of HSP-90 was essentially constant with the prolongation of treatment time. When actin-5 was used, HSP-90 expression changed markedly with treatment time. The results of this study can be used for further research on gene expression inBactrocera cucurbitae

Infestation of Platypodine Beetles (Coleoptera: Curculionidae) on Rubber Trees in China

Lai, Shengchang, Wang, Jianguo, Fu, Yueguan, Duan, Bo, Hongchang, A, Zhang, Ling, Tarno, Hagus (2020): Infestation of Platypodine Beetles (Coleoptera: Curculionidae) on Rubber Trees in China. The Coleopterists Bulletin 74 (3): 626-631, DOI: 10.1649/0010-065X-74.3.626, URL: http://dx.doi.org/10.1649/0010-065x-74.3.62

Influence of Temperature, Photoperiod, and Supplementary Nutrition on the Development and Reproduction of <i>Scutellista caerulea</i> Fonscolombe (Hymenoptera: Pteromalidae)

Scutellista ciruela Fonscolombe has a significant controlling effect on the rubber tree pest, Parasaissetia nigra Nietner. To identify the optimal conditions for the population growth of S. caerulea, we assessed how temperature, photoperiod, and supplementary nutrition affected its development and reproduction. The results demonstrated that the number of eggs laid and parasitism rates of S. caerulea were the highest at 33 °C. The developmental rate of S. caerulea was the fastest and the number of emerged adults the highest. The number of eggs laid and the parasitism rates increased when the light duration increased within a day. Females did not lay any eggs when the whole day was dark. At a photoperiod of 14:10 (L:D), the developmental duration was the shortest and the number of emerged adults was the highest. Adult life span was the longest under a 12:12 (L:D) photoperiod. During the adult stage, supplementary nutrition, such as sucrose, fructose, honey, and glucose, increased the life span of S. caerulea. The life span of S. caerulea was longer when provided with a supplementary diet of sucrose or honey, compared to other tested diets. The results suggested that the most suitable conditions for S. caerulea’s population growth were the following: 30 to 33 °C, with 12 to 14 h of daylight, and the provision of sucrose or honey as supplemental diet for the adults