Entomological Science最新文献

Estimating parasitism rates in the field is essential for developing and evaluating biocontrol strategies using parasitoids. In this study, we developed a simple polymerase chain reaction (PCR)-based method for detecting parasitism of the cassava mealybug Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae) by the primary parasitoid Anagyrus lopezi De Santis (Hymenoptera: Encyrtidae) and its hyperparasitoid Prochiloneurus pulchellus Silvestri (Hymenoptera: Encyrtidae). Primers were designed to amplify partial cytochrome c oxidase subunit I genes of each species, and their sensitivity was evaluated with mealybugs that had been parasitized by A. lopezi 0, 3, and 6 days earlier, and mummified mealybugs containing A. lopezi pupae that had been parasitized by P. pulchellus 0, 3, 6, 9, and 12 days earlier. The detection rate of parasitism by A. lopezi was 100% for all ages of A. lopezi. The detection rate of parasitism by P. pulchellus ranged from 94.1% to 100%, depending on its developmental stage. For P. pulchellus, template DNA was diluted 10 times before PCR because PCR with the original concentration showed low detection rates, presumably due to the presence of PCR inhibitors. Overall, our primers can be considered sufficiently sensitive to be used for detecting each species.

Female fritillary butterflies (Lepidoptera: Nymphalidae: Argynnini) are known to have diversified genital structures, especially at the entrance of the bursa copulatrix. However, the origin and function of such elaborated structures are poorly known to date. We examined the male and female genital structures of six Japanese species selected from five genera/subgenera [Argynnis (Argynnis), Argynnis (Damora), Argynnis (Argyronome), Fabriciana, and Speyeria] of the Argynnini tribe and found that traumatic copulation is widespread in Argynnini. Various male genital structures, such as the uncus, valva, and phallus, can cause wounds to the female genitalia. The eighth venter of the female, where the highest morphological diversity in female genitalia was detected, is hooked and held by the male uncus during copulation. It is very likely that the diversified female genital structure coevolved with the male uncus as a counterpart for traumatic coupling.

As differences in sex pheromones usually act as a barrier against interspecific mating, the fact that the closely related moths Xylena fumosa (Butler) and X. formosa (Butler) (Lepidoptera: Noctuidae: Xyleninae) are commonly attracted to the sex pheromone lure for Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae: Heliothinae) seems unlikely, suggesting that some mechanisms exist between them to mitigate a potential reproductive interference in pheromone communications. Thus, we examined the overlaps in ecological niches of the two species, and their attractiveness to commercial pheromone lures for other moths, through pheromone trap surveys and published reports. Long-term field surveys using traps baited with five to six types of artificial sex pheromone lures including those designed for H. armigera, and information in published works revealed that there was a nonnegligible overlap between the two species in terms of seasonal timing of captures, geographic habitats and host plants. These factors, therefore, did not appear to provide conclusive evidence mitigating reproductive interference. However, there was a slight but significant difference between them in the trends of attraction to different artificial pheromone lures; X. formosa was attracted albeit in a small number to the lures for Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae), whereas X. fumosa was only attracted to those for H. armigera. This suggests that differences in pheromone composition, rather than differences in temporal and spatial distributions, between the two species could play a more significant role in premating reproductive isolations.

Invasive insect species threaten the productivity of ecosystems worldwide, and ecological niche models can be used to predict distributions of invaders and guide management efforts. Ecological niche models can also aid monitoring for invasive species that are globally distributed. One such species is the yellow spotted stink bug (Erthesina fullo Thunberg), a polyphagous pest native to Asia that has established in Europe and South America and threatens specialty crops. Here, we used ecological niche models to predict the potential distribution of E. fullo, and created a website to display predictions. We show that E. fullo has peak occurrence probability in areas with annual mean temperatures around 20°C, and that the occurrence probability increases as maximum monthly temperature reaches up to 38°C. The likelihood of occurrence decreased as annual precipitation increased, but increased with greater precipitation in the wettest and driest months. This suggests E. fullo is most suited to regions that are warm and dry and where most precipitation occurs across only a few months, such as southern North America, central and southern South America, southern Europe, southern Africa, and central and eastern Australia. Given that E. fullo is a highly mobile hitchhiking insect that travels through cargo and other containers to new areas, the potential spread of this species into new regions should be carefully monitored.

The giant water bug Kirkaldyia deyrolli is one of the most well-known endangered aquatic insects in Japan. The population of this species in Kyushu, one of the four major islands of the Japanese Archipelago, is extremely limited. In the present study, we identified a new population of K. deyrolli and undertook population genetic structure analyses based on genome-wide nuclear DNA single nucleotide polymorphisms (SNPs). We collected samples using a nonlethal sampling method and obtained 59,279 SNPs. The results of our study confirm that sufficient SNP data for population genetic structure analysis can be obtained through nonlethal sampling. We determined that the newly identified population is genetically differentiated from a previously identified population on Kyushu. Therefore, this population is considered highly important for the conservation of K. deyrolli in Kyushu.