Journal of Insect Science最新文献

The Sudano-Sahelian and the high Guinea savannahs agroecological zones of Cameroon are suitable for the full development of tree crops, including mango. Unfortunately, fresh fruits exported to local and international markets are frequently rejected due to the presence of fruit fly larvae (Diptera: Tephritidae), resulting in drastic income losses and overuse of chemical control products. To promote sustainable management strategies, a 2-yr study (2020-2021) was conducted in 4 and 3 mixed orchards, respectively. Attacked mangoes showing signs of fruit fly damage were collected and taken to the laboratory to rear and identify fruit flies. Repeated grafting and agroclimatic differences were responsible for dissimilarities between the 2 zones, with 18 and 16 cultivars, respectively. From 2,857 attacked mangoes, 26,707 fruit flies belonging to 4 species were identified: Bactrocera dorsalis, Ceratitis cosyra, Ceratitis fasciventris, and Ceratitis anonae. Climate change was the factor determining the distribution of the 2 most important mango fruit flies: B. dorsalis was a wetland species (dominance/occurrence > 70%), while C. cosyra was a dry-land species (dominance/occurrence > 75%). Both species were responsible for high levels of infestations. Bactrocera dorsalis preferred 3 mango cultivars, namely Palmer and Smith in Zone 1, and Ifack 1 in Zone 2 (infestation > 20 individuals/100 g of mango). The host-plant spectrum of C. cosyra was modified by alternative host plants. Both C. fasciventris and C. anonae were rare. Findings from this study could guide researchers in the development of monitoring tools for fruit fly populations and, subsequently, in reducing the damage they cause to mangoes.

Chemical-based interventions are mostly used to control insects that are harmful to human health and agriculture or that simply cause a nuisance. An overreliance on these insecticides however raises concerns for the environment, human health, and the development of resistance, not only in the target species. As such, there is a critical need for the development of novel nonchemical technologies to control insects. Electrocution traps using UV light as an attractant are one classical nonchemical approach to insect control but lack the specificity necessary to target only pest insects and to avoid harmless or beneficial species. Here we review the fundamental physics behind electric fields (EFs) and place them in context with electromagnetic fields more broadly. We then focus on how novel uses of strong EFs, some of which are being piloted in the field and laboratory, have the potential to repel, capture, or kill (electrocute) insects without the negative side effects of other classical approaches. As EF-insect science remains in its infancy, we provide recommendations for future areas of research in EF-insect science.

The parasitoid wasp, Ooencyrtus kuvanae (Howard) (Hymenoptera: Encyrtidae), is a natural enemy of the spongy moth, a significant forest pest in North America. We investigated the oviposition behavior of O. kuvanae females on spongy moth egg masses by (i) presenting female parasitoids with a single spongy moth egg mass that was replaced every day, 2nd day, 4th day, 8th day, or 16th day (which is the total length of the oviposition period) and (ii) presenting female parasitoids with 1, 2, 4, or 8 egg masses at a time. Offspring developmental length ranged from 18 to 24 days. On average, male offspring exhibited faster developmental times, emerging approximately 1 day ahead of females. The amount of time that adult females spent on an egg mass affected the number of parasitized eggs. Specifically, more offspring emerged in the 4-, 8-, and 16-day treatments than in scenarios involving daily or every second-day egg mass replacement. The percentage of male offspring decreased as the number of egg masses presented to females increased. Interestingly, the total number of female offspring remained constant, but the number of male offspring decreased with an increase in the number of egg masses and time spent by the parent within a patch. The observed sexual dimorphism in development time, the influence of resource availability on offspring sex ratios, and flexible oviposition patterns illustrate the adaptability of O. kuvanae in response to varying conditions. These insights have implications for our understanding of parasitoid-host interactions and their potential role in biological control strategies.

Diaphorina citri, also known as the Asian citrus psyllid, is the main vector of 'Candidatus Liberibacter asiaticus' (CLas) associated with citrus Huanglongbing. It has been reported that D. citri could also be infected by Citrus tristeza virus (CTV), a virus that has been previously reported to be vectored by certain aphid species. In this study, the CTV and CLas profiles in different organs, color variants, developmental stages, or sexes of D. citri insects were analyzed. Although no significant differences were found between nymphs and adults in CTV titers, we found that the third instar nymph of D. citri was more efficient in CTV and CLas acquisition compared to the fourth and fifth instars and adults. With the instars of D. citri development, the relationship between the acquiring of CTV and CLas by D. citri seemed to follow an inverse trend, with the titer of CLas increased and the titer of CTV decreased. No significant differences were observed between the 2 sexes of D. citri in acquiring either CTV or CLas titers in the field. However, no differences were drawn among the 3 color morph variants for CTV titers. CTV titers in the midguts of adult D. citri were significantly higher than those in the salivary glands. Both CTV-positive incidence and CTV titers in the midguts of adult D. citri increased with increasing exposure periods. This study provides new data to deepen our understanding of the CTV-involved interaction between D. citri and CLas.

Geometric morphometrics was used to determine whether geographic isolation could explain differences in wing size and shape between and within continental (27°S to 41°S) and insular (Rapa Nui) populations of Culex pipiens s.s. Linnaeus and their biotypes (f. pipiens and f. molestus). Molecular protocols based on polymorphisms in the second intron of nuclear locus ace-2 (acetylcholinesterase-2) were used to differentiate Cx. pipiens s.s. from Cx. quinquefasciatus Say, and an assay based on polymorphisms in the flanking region of a microsatellite locus (CQ11) was used to identify biotypes. Culex pipiens f. molestus and hybrids shared larval habitats in all continental sites, while Cx. pipiens f. pipiens was found in 5 of the 10 sites. Only biotype molestus was found in Rapa Nui (Easter Island) Pipiens and molestus biotypes occur sympatrically in aboveground locations, and only molestus was found in the underground site (ME). Biotype molestus was dominant in rural locations and preferably anthropophilic. These results agree with the ecological descriptions previously reported for the biotypes of Cx. pipiens s.s. Procrustes ANOVA only showed differences in centroid size between biotypes in females and males and did not show significant differences in wing shape. However, we found significant differences among the geographic areas in the centroid size and wing shape of both females and males. Particularly, the population of Rapa Nui Island had shorter wings than the continental populations. The results highlight the effects of geographic and environmental processes on morphotypes in vector mosquitoes.

The Asian citrus psyllid (ACP) is the main vector of Citrus Huanglongbing, the most damaging citrus disease, causing significant financial losses in the citrus industry. Global warming has expanded the habitat of this pest, allowing it to continue its northward migration to China. Population genetic information of ACP is fundamentally essential for species management. This study investigated the genetic diversity and population structure of Chinese ACP using the mitochondrial cytochrome oxidase subunit I gene by dataset comprised 721 sequences from 27 geographic sites in China. Low haplotype diversity (0.323 ± 0.022) and low nucleotide diversity (0.00071 ± 0.00007) were observed in the entire population, which may indicate recent founder events. Twenty-three haplotypes were identified and clustered into 2 haplogroups: haplogroup I and haplogroup II. Haplogroup II included only 2 unique haplotypes, which occurred exclusively in the Southwest China ACP population. Genetic differentiation analyses were also indicative of Southwest China population was significantly differentiated from the remaining populations. Demographic history analysis showed that ACP population in China has experienced demographic expansion. Our results provided a better understanding of the genetic distribution patterns and structures of ACP populations in China.