Diaphania angustalis Snellen (Lepidoptera: Crambidae) is the main defoliator of Alstonia schalaris. In this article, observation of external morphological and ultrastructure structure of adult antennae of D. angustalis was carried out using the scanning and transmission electron microscope. The results showed that both male and female antennae were filiform and could be divided into scape, pedicel, and flagellum. There are eight types and two subtypes of antennal sensilla, namely, sensilla trichodea, sensilla chaetica (I & II), sensilla coeloconica, sensilla auricillica, sensilla styloconica, sensilla squamiformia, capitate peg, and Böhm bristles. Most sensilla are concentrated in venter and the sides of antennae. Analyses on morphological and quantitative differences of antennal sensilla between male and female adults. The size of SCo is significantly different between male and female. In terms of quantity, only SSt and CP have no significant differences between male and female. By comparing the existing antennal sensilla of Crambidae, it is found that STr, SCh, SCo, and SAu are common sensilla. These results can contribute to further research on the function of sensilla of D. angustalis relating to its behavior. A detailed description is provided of the antennal sensilla in Diaphania angustalis. Diaphania angustalis has the rare sensilla of capitate peg in Crambidae. No sexual dimorphism of sensillum types is found in the species. The number and distribution of sensilla trichodea, sensilla chaetica, sensilla coeloconica, and sensilla auricillica sensillum are different.

Leptocybe invasa Fisher & La Salle (Hymenoptera, Eulophidae) is an invasive pest in Eucalyptus plantations throughout the world. Potential biological control agents for L. invasa were investigated in the Fujian, Guangdong, Hainan, Guangxi, Jiangxi, and Sichuan provinces of China, where Eucalyptus spp. have been severely damaged by the eucalyptus gall wasp. Three hymenopteran parasitoids of L. invasa were identified: Quadrastichus mendeli Kim & La Salle (Eulophidae), Aprostocetus causalis La Salle & Wu (Eulophidae), and Megastigmus viggianii Narendran & Sureshan (Torymidae); M. viggianii is newly recorded in China. The percentages of parasitization by Q. mendeli, A. causalis, and M. viggianii were 2.96%–19.53%, 2.30%–26.38%, and 24.93%, respectively. The longevity and body length of females were significantly greater than for males in A. causalis and M. viggianii. No males of Q. mendeli were found in China. These parasitoids could be used as biological agents for L. invasa in China.

The genus Leptocybe Fisher & La Salle (Hymenoptera: Eulophidae) and its type species L. invasa were first described in 2004. Leptocybe spp. are global pests of eucalyptus plantations, and parasitoids play an important role in their control. In this review, we describe the species, distribution, biology, ecology and parasitism levels of Leptocybe spp. parasitoids and the problems associated with biological control programmes against Leptocybe spp. Additionally, prospects for the use of conservation or augmentative biological control programmes against Leptocybe spp. are discussed. Worldwide, approximately 23 species of parasitoids of Leptocybe spp. in 7 families and 10 genera have been found to date. Comparing the parasitism levels of the parasitoids showed that Quadrastichus mendeli, Selitrichodes neseri and several (approximately 4) native Megastigmus spp. could be exploited to manage Leptocybe spp. Available information on the Leptocybe spp. parasitoids is expected to improve our understanding related to ongoing studies of biological control programmes against Leptocybe spp.

The antennal sensilla of female Quadrastichus mendeli Kim & La Salle (Hymenoptera: Eulophidae: Tetrastichinae) were observed with scanning and transmission electron microscopy in this study. The antenna of Q. mendeli was geniculate, and the flagellum was composed of seven subsegments. Six distinct types of sensory receptors were observed, including sensilla basiconic capitate peg, sensilla böhm, sensilla chaetica, sensilla campaniformia, sensilla placodea and sensilla trichodea. Sensilla basiconic capitate pegs were found on the flagellomeres, and Böhm sensilla were found on the basal part of scape and the pedicel. Two morphological subtypes of sensilla chaetica were found on the antennae, and sensilla campaniformia were only found on the pedicel. Sensilla placodea were divided into two morphological subtypes that were found on the flagellomeres. Sensilla trichodea were found on the 2nd-6th flagellomere. By comparison to existing antennal sensilla, it was found that sensilla basiconic capitate peg, sensilla chaetica, sensilla placodea and sensilla trichodea were the most common sensilla of the parasitoids of Eulophidae. The external and internal morphology, types, number, distribution, length, and width of these sensilla were described, and their possible functions are discussed in conjunction with the host-detection behavior. Future studies on the host location mechanisms in Q. mendeli will be facilitated by these observations.

Background Insects harbor a myriad of microorganisms, many of which can affect the sex ratio and manipulate the reproduction of the host. Leptocybe invasa is an invasive pest that causes serious damage to eucalyptus plantations, and the thelytokous parthenogenesis, low temperature resistance, protection in galls, generation overlap and small body of L. invasa contribute to its rapid invasion and population growth. However, the endosymbiotic bacterial composition, abundance and sex differences of L. invasa remain unclear. Therefore, this research aimed to identify the bacterial communities in L. invasa adults and compare them between the sexes of L. invasa lineage B. Results The Illumina MiSeq platform was used to compare bacterial community composition between females and males of L. invasa by sequencing the V3–V4 region of the 16S ribosomal RNA gene. A total of 1,320 operational taxonomic units (OTUs) were obtained. These OTUs were subdivided into 24 phyla, 71 classes, 130 orders, 245 families and 501 genera. At the genus level, the dominant bacteria in females and males were Rickettsia and Rhizobium, respectively. Conclusion The endosymbiotic bacteria of L. invasa females and males were highly diverse. There were differences in the bacterial community of L. invasa between sexes, and the bacterial diversity in male specimens was greater than that in female specimens. This study presents a comprehensive comparison of bacterial communities in L. invasa and these data will provide an overall view of the bacterial community in both sexes of L. invasa with special attention on sex-related bacteria.

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Allotraeus asiaticus Schwarzer and Callidiellum villosulum Fairmaire are repeatedly intercepted in wood and wood products all over the world. As two common stem borers of Cunninghamia lanceolata (Lambert) Hooker, to further understanding of the differences in their living habits, behaviors and the mechanism of insect-host chemical communication, we observed the external morphology, number and distribution of antennal sensilla of A . asiaticus and C . villosulum with scanning electron microscopy (SEM), respectively. The results showed that 1st-5th subsegments of the flagellum are spined endoapically in A . asiaticus which is different from the previous report (1st-3rd of the flagellomere). Meanwhile, there were five subsegments on the flagellum of C . villosulum that were clearly specialized as serrated shapes on the 4th-8th flagellomeres. Four types (ten subtypes) of sensilla were both found on the antennae of these two fir longhorn beetles, named Böhm bristle (Bb), sensilla trichodea (ST I and II), sensilla basiconica (SB I, II and III), sensilla chaetica (SCh I, II, III and IV). There is one additional kind of morphological type of sensilla found on the antennae of C . villosulum compared to A . asiaticus which was related to their habit of laying eggs only on dry and injured fir branches, named sensilla campaniformia (SCa). These differences may vary according to their own biological habits. For research purposes, the observed difference in the sensillum distribution and function between the two fir longhorn beetles will greatly facilitate the design of better semiochemical control methods of these insect pests.

Little is known of the olfactory mechanisms of host detection in the ovipositors of endoparasitoids and ectoparasitoids. An endoparasitoid Aprostocetus causalis La Salle & Wu (Hymenoptera: Eulophidae) and an ectoparasitoid Quadrastichus mendeli Kim & La Salle (Hymenoptera: Eulophidae: Tetrastichinae) are the two parasitoids of the eucalyptus gall wasp Leptocybe spp. Structures and sense organs of ovipositors of A. causalis and Q. mendeli were studied using scanning and transmission electron microscopy, which provided essential information for exploring the mechanism of host detection by endoparasitoid and ectoparasitoid. The ovipositors of two parasitoids consisted of the first and second valvulae and ended in a pointed tip. There were three types of microtrichia, two types of sensilla chaetica, and one type of sensilla campaniformia on the ovipositors of A. causalis and Q. mendeli. However, Q. mendeli has the fourth type of microtrichia on the ovipositor. The morphology, types, distribution, length, and width of these sensilla and microtrichia were described, and their possible functions are discussed in conjunction with the stinging, oviposition, and the host selection process.