Insects

The Chinese oak silkworm is commonly used in pupal diapause research. In this study, a long photoperiod was used to trigger pupal diapause termination. Genes encoding three hormones, namely prothoracicotropic hormone (PTTH), ecdysis triggering hormone (ETH), and eclosion hormone (EH), were studied. Additionally, ecdysteroids (mainly 20-hydroxyecdysone, 20E) were quantified by HPLC. Pupal diapause stage was determined by measuring respiratory intensity. The pupae enter a low metabolic rate, which starts approximately 1 month after pupal emergence. ApPTTH expression showed a small increase at 14 days and then a larger increase from 35 days under the long photoperiod treatment. A similar pattern was observed for the titer of 20E in the hemolymph. However, ApETH expression later increased under the long photoperiod treatment (42 days) just before eclosion. Moreover, ApEH expression increased from 21 to 35 days, and then decreased before ecdysis. These results suggest that hormone-related gene expression is closely related to pupal development. Our study lays a foundation for future diapause studies in A. pernyi. Full article

Depending on their life cycle, grape phylloxera (Daktulosphaira vitifoliae Fitch) leaf-feeding populations are initiated through asexually produced offspring or sexual recombination. The vine’s initial foliar larvae may originate from root-feeding phylloxera or wind-drifted foliar larvae from other habitats. Though some studies have reported phylloxera leaf-feeding in commercial vineyards, it is still unclear if they are genetically distinct from the population structure of these two sources. Using seven SSR-markers, this study analyzed the genetic structure of phylloxera populations in commercial vineyards with different natural infestation scenarios and that of single-plant insect systems that exclude infestation by wind-drifted larvae. We saw that during the vegetation period, phylloxera populations predominately go through their asexual life cycle to migrate from roots to leaves. We provided evidence that such migrations do not exclusively occur through wind-drifted foliar populations from rootstock vines in abandoned thickets, but that root populations within commercial vineyards also migrate to establish V. vinifera leaf populations. Whereas the former scenario generates foliar populations with high genotypic diversity, the latter produces population bottlenecks through founder effects or phylloxera biotype selection pressure. We finally compared these population structures with those of populations in their native habitat in North America, using four microsatellite markers. Full article

Ceratomegilla undecimnotata (Coleoptera: Coccinellidae) is a common aphidophagous coccinellid predator used in biological control against aphid pests. Knowing toxicity, lethal, and sublethal effects of insecticides on natural enemies is essential in order to incorporate them into Integrated Pest Management (IPM). In the present study, the lethal and sublethal effects of imidacloprid and deltamethrin were evaluated on the fourth instar larvae of C. undecimnotata and subsequently on the full life cycle. Our results strongly suggest that sublethal and low doses of imidacloprid and deltamethrin at LD₁₀ and LD₃₀ affected fourth instar larvae duration time, adult preoviposition period, total preoviposition period, and fecundity. Moreover, the intrinsic (r) and finite (λ) rate of increase and the net reproduction rate (R₀) significantly decreased in populations treated with imidacloprid compared to the control population. The data clearly suggest that imidacloprid and deltamethrin have a negative influence on population growth parameters of C. undecimnotata at sublethal and low doses and, therefore, these insecticides should be used with caution within the context of IPM. Full article

In agricultural systems, chemical ecology and the use of semiochemicals have become critical components of integrated pest management. The categories of semiochemicals that have been used include sex pheromones, aggregation pheromones, and plant volatile compounds used as attractants as well as repellents. In contrast, semiochemicals are rarely utilized for management of insects used in weed biological control. Here, we advocate for the benefit of chemical ecology principles in the implementation of weed biocontrol by describing successful utilization of semiochemicals for release, monitoring and manipulation of weed biocontrol agent populations. The potential for more widespread adoption and successful implementation of semiochemicals justifies multidisciplinary collaborations and increased research on how semiochemicals and chemical ecology can enhance weed biocontrol programs. Full article

Aprostocetus brevipedicellus, a eulophid gregarious egg parasitoid of lepidopterous pests, is a potential biological control agent for the control of many forest pests. A dominant factitious host, Antheraea pernyi, has been widely used for mass rearing several parasitoids in China. However, whether A. pernyi eggs are suitable for A. brevipedicellus rearing remains unclear. Here we evaluated A. brevipedicellus parasitism and fitness of their offspring on A. pernyi eggs with five different treatments, including manually-extracted, unfertilized and washed eggs (MUW), naturally-laid, unfertilized and washed eggs (NUW), naturally-laid, unfertilized, and unwashed (NUUW) eggs, naturally-laid, fertilized and washed eggs (NFW), and naturally-laid, fertilized and unwashed eggs (NFUW). The results showed that A. brevipedicellus could parasitize host eggs in all treatments but significantly preferred MUW eggs to other treatments. Moreover, A. brevipedicellus preferred unfertilized eggs to fertilized eggs and parasitized more washed eggs than unwashed. The pre-emergence time of parasitoid offspring emerging from fertilized eggs was shorter than that from unfertilized eggs. More parasitoid offspring emerged from unwashed eggs than that from washed eggs. The offspring emergence rate was high (>95%) and also female-biased (>85%) among all egg treatments. The egg load of female parasitoid offspring emerging from MUW and NUW eggs was 30–60% higher than the remaining treatments. Overall, MUW eggs of A. pernyi are the most suitable for the mass production of A. brevipedicellus. Full article

Investigation of mating-induced trade-offs between reproduction and survival is conducive to provide evolutionary insights into reproductive strategies and aging. Here, we used RNAseq and bioinformatics to reveal mating-induced changes of genes and pathways related to reproduction and survival in female Cephalcia chuxiongica, a pine defoliator with facultative parthenogenesis and long larval dormancy. Results showed that mating induced substantial downregulation on genes and pathways associated to immunity, stress response, and longevity. However, mating induced divergent reproductive response, with downregulation on genes and pathways related to egg production while upregulation on genes and pathways related to egg fertilization. Considering the nature of limited resources in adults, low fecundity, and egg protection behavior in C. chuxiongica, we suggest that mating triggers trade-offs between reproduction and survival in this insect and females of this species may have evolved specific strategies to adapt to the environmental and hosts’ conditions, e.g., restrict whole fecundity to ensure higher fertilization and offspring’s survival. Moreover, mating induced significant responses on genes and pathways that play important roles in vertebrate reproduction while their function in insects are unclear, such as the progesterone-mediated oocyte maturation pathway; the significant regulation after mating suggests that their function may be evolutionarily conserved in animal kingdom. Full article

Mosquitoes-borne diseases are major public health issues particularly in Africa. Vector control interventions and human-made environmental/climatic changes significantly affect the distribution and abundance of vector species. We carried out an entomological survey targeting host-seeking mosquitos in two different ecological contexts—coastal and inland—in Senegal, by CDC-light and BG-sentinel traps. Results show high predominance of Culex quinquefasciatus (90%) and of Anopheles arabiensis within malaria vectors (46%), with mean numbers of females/trap/nights =8 and <1, respectively, reinforcing previous evidence of changes in species composition and abundance, highlighting thus increasing risk of transmission of filariasis and emerging arboviruses in the Senegambia region. From the methodological perspective, results show a higher specificity of BG traps for Cx. quinquefasciatus and of CDC traps for An. gambiae s.l. and highlight that, despite both traps target the host-seeking fraction of the population, they provide different patterns of species abundance, temporal dynamics and host-seeking activity, leading to possible misinterpretation of the species bionomics. This draws attention to the need of taking into account trapping performance, in order to provide realistic quantification of the number of mosquitoes per units of space and time, the crucial parameter for evaluating vector–human contact, and estimating risk of pathogen transmission. Full article

French broom (Genista monspessulana) (Fabaceae) is a perennial species native to the Mediterranean basin. Introduced in the 19th century as an ornamental plant, it is currently invasive in California and Australia. The current research is focused on biocontrol with the use of the phytophagous weevil Lepidapion argentatum (Brentidae). Its capacity to develop both in the stem galls and pods of French broom makes it a promising candidate. The impact on the reproduction of French broom was studied in Southern France and revealed that it could effectively reduce the number of viable seeds by 18.8%, but also increased the number of aborted seeds by 10% within the attacked pods. To evaluate the specificity of L. argentatum, choice and no-choice tests were performed in 2012 and 2015 on a total of 36 non-target closely related species. Results revealed the presence of galls and larvae in the stems of seven species, including two endemic Californian lupines; i.e., Lupinus arboreus blue and Lupinus chamissonis. In the future, new tests will be conducted to determine if L. argentatum is able to complete its entire development lifecycle on the non-target species where galls have previously been observed. Full article

Sperm storage in the spermathecae of honeybee (Apis mellifera) queens is vital for reproduction of honeybees. However, the molecular mechanisms whereby queens store sperm in a viable state over prolonged periods in the spermatheca are not fully understood. Here, we conducted RNA sequencing analysis of the spermathecae in both virgin and mated A. mellifera queens 24 h after mating and observed that the genes encoding transferrin (Tf) and major royal jelly proteins (MRJPs) were differentially expressed in the spermathecae of mated queens. The concentrations of Tf and antioxidant proteins such as superoxide dismutase 1, catalase, and glutathione peroxidase as well as the levels of reactive oxygen species, H₂O₂, and iron were higher in the spermathecal fluid of the mated queens than in virgin queens. Tf upregulation is likely to perform a protective role against the Fenton reaction occurring between iron and H₂O₂ in the antioxidant pathway in the mated queen’s spermathecal fluid. Furthermore, MRJPs—especially MRJP1, MRJP4, and MRJP6—were upregulated in the mated queen’s spermathecal fluid, indicating that they may serve as antimicrobial and antioxidant agents as well as an energy source for stored sperm in the spermathecal fluid of honeybee queens. Together, our findings show that Tf and MRJPs are upregulated in the spermatheca and spermathecal fluid of mated honeybee queens. Full article

Natural history collections provide an invaluable basis for systematics, ecology, and conservation. Besides being an important source of DNA, museum specimens may also contain a plethora of natural products. Especially, dried insect collections represent a global repository with billions of inventoried vouchers. Due to their vast diversity, insects possess a great variety of defensive compounds, which they either produce autogenously or derive from the environment. Here, we present a case study on fireflies (Coleoptera: Lampyridae), which produce bufadienolides as a defense against predators. These toxins belong to the cardiotonic steroids, which are used for the treatment of cardiac diseases and specifically inhibit the animal enzyme Na⁺/K⁺-ATPase. Bufadienolides have been reported from only seven out of approximately 2000 described firefly species. Using a non-destructive approach, we screened 72 dry coleopteran specimens for bufadienolides using HPLC-DAD and HPLC-MS. We found bufadienolides including five novel compounds in 21 species of the subfamily Lampyrinae. The absence of bufadienolides in the phylogenetically related net-winged beetles (Lycidae) and the lampyrid subfamilies Luciolinae and Lamprohizinae indicates a phylogenetic pattern of bufadienolide synthesis. Our results emphasize the value of natural history collections as an archive of chemical information for ecological and evolutionary basic research and as an untapped source for novel bioactive compounds. Full article

Pollination plays a significant role in the agriculture sector and serves as a basic pillar for crop production. Plants depend on vectors to move pollen, which can include water, wind, and animal pollinators like bats, moths, hoverflies, birds, bees, butterflies, wasps, thrips, and beetles. Cultivated plants are typically pollinated by animals. Animal-based pollination contributes to 30% of global food production, and bee-pollinated crops contribute to approximately one-third of the total human dietary supply. Bees are considered significant pollinators due to their effectiveness and wide availability. Bee pollination provides excellent value to crop quality and quantity, improving global economic and dietary outcomes. This review highlights the role played by bee pollination, which influences the economy, and enlists the different types of bees and other insects associated with pollination. Full article

Oak seed predatory weevils occurring in Poland are prone to increased interspecific competition due to the limited number of Quercus species, compared to southern Europe, in which they can develop. Therefore, analyses on the preferences of three weevil species for acorn sizes chosen for reproduction, as well as on reproductive period duration, were performed. Cafeteria-type experiments were set for females of three species associated with one oak species. Females were allowed to choose and oviposit in acorns of different sizes and growth stages. Research revealed statistically significant differences between the masses of acorns chosen for oviposition by females of Curculio glandium (the biggest), C. pellitus (medium), and C. venosus (the smallest). Studied weevils also differed in terms of the beginning of the reproductive period, which corresponded with the increasing mass of growing acorns. Moreover, C. glandium was observed to be the only species to perform radial egg galleries and lay a considerably higher and varied number of eggs. The results support the hypothesis of a strategy aimed at reducing interspecific competition between Curculio spp. in terms of limited host plant species number. Full article

Belminus santosmalletae, a new triatomine species, is described based on a specimen from Panama, deposited in the collection of the National Museum of Natural History (NMNH), Smithsonian Institution, Washington, DC, USA. Attempts failed to identify this specimen using the keys by Lent and Wygodzinsky (1979) and Sandoval et al. (2007). A comparison was made with specimens of Belminus Stål, 1859 specimens deposited at the Triatominae collection at the Oswaldo Cruz Institute (CTIOC), Rio de Janeiro, Brazil; and with previous descriptions of Belminus species. These comparisons showed the specimen represents a new species, described in the present paper. It differs from other species of the genus mainly by the grainy tegument, scarce pilosity along the body, and the number of tubercles observed on the pronotum. Full article

Pollinators are being threatened globally by urbanisation and agricultural intensification, driven by a growing human population. Understanding these impacts on landscapes and pollinators is critical to ensuring a robust pollination system. Remote sensing data on land use attributes have previously linked honeybee nutrition to land use in the Western Honeybee (Apis mellifera L.). Here, we instead focus on the less commonly studied Apis cerana japonica—the Japanese Honeybee. Our study presents preliminary data comparing forage (honey and pollen) with land use across a rural-urban gradient from 22 sites in Kyushu, southern Japan. Honey samples were collected from hives between June 2018 and August 2019. Pollen were collected and biotyped from hives in urban and rural locations (n = 4). Previous studies of honey show substantial variation in monosaccharide content. Our analysis of A. cerana japonica honey found very little variation in glucose and fructose (which accounted for 97% of monosaccharides), despite substantial differences in surrounding forage composition. As expected, we observed temporal variation in pollen foraged by A. cerana japonica, likely dependent on flowering phenology. These preliminary results suggest that the forage and nutrition of A. cerana japonica may not be negatively affected by urban land use. This highlights the need for further comparative studies between A. cerana japonica and A. mellifera as it could suggest a resilience in pollinators foraging in their native range. Full article

The loss of honey bees has drawn a large amount of attention in various countries. Therefore, the development of efficient methods for recovering honey bee populations has been a priority for beekeepers. Here we present an extended literature review and report on personal communications relating to the characterization of the local and bred stock of honey bees in the Russian Federation. New types have been bred from local colonies (A. mellifera L., A. m. carpatica Avet., A. m. caucasia Gorb.). The main selection traits consist of a strong ability for overwintering, disease resistance and different aptitudes for nectar collection in low and high blooming seasons. These honey bees were certified by several methods: behavioral, morphometric and genetic analysis. We illustrate the practical experience of scientists, beekeepers and breeders in breeding A. mellifera Far East honey bees with Varroa and tracheal mite resistance, which were the initial reasons for breeding the A. mellifera Far Eastern breed by Russian breeders, Russian honey bee in America, the hybrid honey bee in Canada by American breeders, and in China by Chinese beekeepers. The recent achievements of Russian beekeepers may lead to the recovery of beekeeping areas suffering from crossbreeding and losses of honey bee colonies. Full article

The peacock butterfly is abundant and widespread in Europe. It is generally believed to be univoltine (one generation per year): adults born in summer overwinter and reappear again in spring to reproduce. However, recent flight patterns in western Europe mostly show three peaks during the year: a first one in spring (overwintering butterflies), a second one in early summer (offspring of the spring generation), and a third one in autumn. It was thus far unclear whether this autumn flight peak was a second new generation or consisted of butterflies flying again in autumn after a summer rest (aestivation). The life cycle of one of Europe’s most common butterflies is therefore still surprisingly inadequately understood. We used hundreds of thousands of observations and thousands of pictures submitted by naturalists from the public to the online portal observation.orgin Belgium and analyzed relations between flight patterns, condition (wear), reproductive cycles, peak abundances, and phenology to clarify the current life history. We demonstrate that peacocks have shifted towards two new generations per year in recent decades. Mass citizen science data in online portals has become increasingly important in tracking the response of biodiversity to rapid environmental changes such as climate change. Full article

Black soldier fly (BSF, Hermetia illucens) larvae are considered as insects with a high potential to convert organic waste into high-value products. The objective of this study was to investigate the growth performance, waste reduction efficiency, and nutritional composition of BSF reared on different ratios of coconut endosperm (C) and soybean curd residue (S), with or without supplementation, compared to standard diets (Gainesville: G and starter chicken diet: CK). Seven-day-old larvae were randomly divided into eight experimental groups (G, CK, and three different ratios of C and S with or without supplementation) with three replicates with an equal weight of larvae. The supplement contained calcium, phosphorus, amino acids, and a mineral–vitamin premix which was formulated to correlate with CK. Each replicate was terminated, measured, and evaluated when 40% of larvae had reached prepupal stage. The highest larval weight gain was presented in BSF fed CK, followed by those fed coconut endosperm and soybean curd residue at a ratio of 20:80 (C20S80), and coconut endosperm and soybean curd residue at a ratio of 50:50 (C50S50) without supplementation (numbers after C and S represent their percentage in the formulation; p < 0.001). Harvesting was delayed in the BSF fed C80S20 with and without supplementation (p < 0.001). The number of total larvae and prepupae was not significantly different between groups (p > 0.05). The greatest waste reduction efficiency was observed in the G, C50S50, and C20S80 groups without supplementation (p < 0.001). All groups with supplementation had a higher proportion of ash in both larvae and prepupae compared to non-supplemented groups (p < 0.001), but lower growth performance. The highest percentage of crude protein in larvae was presented in the Gainesville and C20S80 groups followed by the CK and C50S50 groups (p < 0.001). Equal proportions of C and S without supplementation are suggested as a rearing substrate. However, growth performance was lower than for CK; therefore, further studies could investigate cost-efficient techniques to promote this parameter. Full article

The harlequin ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), is a generalist predator and an effective biocontrol agent of various insect pests that has been exploited for the control of aphid pests in the greenhouse and field. However, insecticides are widely used to control aphid pests worldwide and the potential non-target effects of sulfoxaflor and imidacloprid for controlling aphid pests towards this biocontrol agent are little known. Although both sulfoxaflor and imidacloprid act on nicotinic acetylcholine receptors of insects, sulfoxaflor has a novel chemical structure compared with neonicotinoids. We assessed the lethal, sublethal and transgenerational effects of sulfoxaflor and imidacloprid on H. axyridis simultaneously exposed via ingestion of contaminated prey and via residual contact on the host plant at LC₂₀ and LC₅₀ doses estimated for the cotton aphid. Imidacloprid significantly reduced the survival of H. axyridis adults compared to sulfoxaflor at the same lethal concentration against cotton aphid. Both concentrations of imidacloprid and sulfoxaflor reduced the proportion of ovipositing females, and both concentrations of imidacloprid and sulfoxaflor, except LC₂₀ dose of sulfoxaflor, reduced the fecundity and fertility of the parental generation. In the progeny of imidacloprid- and sulfoxaflor-exposed parents, both tested LC₅₀ concentrations significantly decreased the juvenile survival rate, and both concentrations of imidacloprid and sulfoxaflor, except LC₂₀ dose of sulfoxaflor, prolonged the development time. Our findings provide evidence of the negative influence of imidacloprid and sulfoxaflor at low lethal concentrations on the harlequin ladybird and on the progeny of exposed individuals, i.e., transgenerational effects. Hence, these findings stress the importance of optimizing the applications of imidacloprid and sulfoxaflor for the control of aphid pests, aiming at preserving the biocontrol services provided by H. axyridis throughout the integrated pest management approach. Full article