Attraction of Adults of Cyclocephala lunulata and Cyclocephala barrerai (Coleoptera: Scarabaeoidea: Melolonthidae) towards Bacteria Volatiles Isolated from Their Genital Chambers

In the study of the chemical communication of adults of the Melolonthidae family, bacteria have been observed in the epithelium of the genital chamber; possibly, bacteria are involved in the production of sex attractants in their hosts. Therefore, it is important to identify the volatile organic compounds from bacteria (VOCsB) released by these microorganisms and study the biological activity stimulated by VOBCs in adults of Melolonthidae. In this study, bacteria were isolated from the genital chamber of Cyclocephala lunulata and Cyclocephala barrerai, from which VOCsB were extracted using static headspace solid-phase microextraction (SHS-SPME) and dynamic headspace Super Q solid-phase extraction (DHS-SPE) and analyzed using gas chromatography-mass spectrometry. The effect of VOCsB on the hosts and conspecifics was evaluated utilizing an olfactometer and electroantennography (EAG). Two species of Enterobacteria were isolated from the genital chamber of each female species, and VOCsB derived from sulfur-containing compounds, alcohols, esters, and fatty acids were identified. An attraction response was observed in olfactometry studies, and antennal responses to VOCsB were confirmed in EAG bioassays. With these results, new perspectives on the relationship between these beetles and their bacteria emerge, in addition to establishing a basis for management programs in the future.

Comparing Performance of Synthetic Sex Attractants and a Semisynthetic Bisexual Lure in Orthosia and Conistra Species (Lepidoptera: Noctuidae)

The performance of a semisynthetic bisexual lure (SBL, containing isoamyl alcohol, acetic acid and red wine) previously found attractive for a number of noctuids was compared with that of the respective synthetic sex attractants of Orthosia cerasi (=stabilis), O. cruda, O. gothica, O. incerta, Anorthoa munda and Conistra vaccini. The respective sex attractants performed significantly better in the Orthosia spp. than the SBL lure, which, although regularly catching low numbers of both females and males, did not differ significantly from zero catch in unbaited control traps. On the other hand, the SBL lure performed as well as the sex attractant in C. vaccini. Sizeable catches of C. rubiginea, C. rubiginosa and C. erythrocephala were also recorded in traps with the SBL lure. The SBL lure can prove to be a useful tool in ecological and faunistical studies of Conistra and related hibernating Xylenini species.

The application of sex attractant traps for studying the Zygaenidae (Lepidoptera) fauna of Albania

In Albania, the Zygaenidae family comprises a relatively rich fauna in the Balkans. They have been studied so far using specimens collected only by using entomological nets or by hand-picking. Two groups of sticky Delta traps baited with: 1) a synthetic sex pheromone compound of the Asian species Illiberis rotundata Jordan, 1907 and its opposite enantiomer, alone and in a mixture, and 2) known sex attractants and experimental lures of the genus Zygaena were used in the field in seven localities in southern Albania in 2017 for studying the Procridinae and Zygaeninae fauna, respectively. Four species belonging to the genera Zygaena, Adscita and Jordanita were captured and identified: Zygaena (Zygaena) filipendulae (Linnaeus, 1758), Zygaena (Agrumenia) carniolica (Scopoli, 1763), Adscita (Tarmannita) mannii (Lederer, 1853) and Jordanita (Tremewania ) notata (Zeller, 1847). A. mannii and J. notata were newly recorded in the Counties of Korçë and Gjirokastër. Z. filipendulae was recorded for the first time in the Gjirokastër County and in the municipalities of Prrenjas (Elbasan County) and Finiq (Vlorë County), while Z. carniolica was newly recorded in Prrenjas municipality. Some other sex attractants did not work for either the target species or for other related ones, which we discuss in relation to species cross attraction and geographical variation.

Results of long-term use of pheromone traps to monitor harmful tortricid moths in Leningrad Region of Russia

Monitoring the population dynamics of harmful moths using synthetic sex attractants in Leningrad Region was carried out in the fruit experimental orchard of St. Petersburg Agrarian University (Pushkin) and small private orchards of Pushkin district. As a result of the analysis of many years temperature characteristics of vegetation seasons in the Leningrad Region and calculation of the sums of effective temperatures, it has been found that the codling moth had high numbers and developed in two full generations in 1999, 2002, 2006, 2013 and 2018. The complex of phytophagous leaf rollers as a whole can cause sometimes significant harm to both industrial orchards and homestead lands, because the economic threshold of harmfulness by yield losses is often achieved, when plants are damaged by more than one pest species, each of which causing only weak harm. As a general conclusion, the complex of orchard leaf rollers is a dynamic system. Their development and numbers ratio is influenced by weather conditions of a year and climate changes in general.

Bx-daf-22 Contributes to Mate Attraction in the Gonochoristic Nematode Bursaphelenchus xylophilus

Studying sex communication is necessary to develop new methods to control the population expansion of gonochoristic species Bursaphelenchus xylophilus, the pathogen of pine wilt disease (PWD). Small chemical signals called ascarosides have been reported to attract potential mates. However, they have not been studied in the sex attraction of B. xylophilus. Here, we confirmed the sex attraction of B. xylophilus using a chemotaxis assay. Then, we cloned the downstream ascaroside biosynthetic gene Bx-daf-22 and explored its function in the sex attraction of B. xylophilus through bioinformatics analysis and RNA interference. The secretions of females and males were the sources of sex attraction in B. xylophilus, and the attractiveness of females to males was stronger than that of males to females. Compared with daf-22 of Caenorhabditis elegans, Bx-daf-22 underwent gene duplication events, resulting in Bx-daf-22.1, Bx-daf-22.2, and Bx-daf-22.3. RNA interference revealed that the attractiveness of female secretions to males increased after all three Bx-daf-22 genes or Bx-daf-22.3 had been interfered. However, the reciprocal experiments had no effect on the attractiveness of male secretions to females. Thus, Bx-daf-22 genes, especially Bx-daf-22.3, may be crucial for the effectiveness of female sex attractants. Our studies provide fundamental information to help identify the specific components and signal pathways of sex attractants in B. xylophilus.