The rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), is a destructive pest that causes damage to rice crops worldwide. The olfactory system is critical for host or mate location by weevils, but only limited information about the molecular mechanism of olfaction-related behaviour has been reported in this insect. In this study, we conducted SMRT-seq transcriptome analysis and obtained 54,378 transcripts, 38,706 of which were annotated. Based on these annotations, we identified 40 candidate chemosensory genes, including 31 odorant-binding proteins (OBPs), six chemosensory proteins (CSPs) and three sensory neuron membrane proteins (SNMPs). Phylogenetic analysis showed that LoryOBPs, LoryCSPs and LorySNMPs were distributed in various clades. The results of tissue expression patterns indicated that LoryOBPs were highly abundant in the antennae, whereas LoryCSPs were highly abundant not only in the antennae but also in the abdomen, head and wings. Our findings substantially expand the gene database of L. oryzophilus and may serve as a basis for identifying novel targets to disrupt key olfactory genes, potentially providing an eco-friendly strategy to control this pest in the future.

Male mating success depends on various traits and factors, and correctly identifying these traits can be key in the context of pest management. For tephritid pests, controlled through the sterile insect technique (SIT) traits, such as male size, can be manipulated through mass-rearing procedures. Thus, it is particularly important to understand whether male size can favor mating success. Here, we evaluated mating success of males of different sizes in Anastrepha ludens and Anastrepha obliqua, two species controlled through SIT. For both species, a morphometric analysis was performed of mated and unmated mass-reared and wild males in field cages. In both A. ludens and A. obliqua, wild females did not discriminate their mates based on male size and mated more frequently with wild males regardless of size. For mass-reared males, we found no evidence of an advantage of the large males compared to small males in mating success. However, we did find differences between the morphometric traits of mass-reared and wild males. In A. ludens, traits associated to mating success were Face Width (FW), Head Width (HW), Thorax Length (TL) and Wing Length (WL), and for A. obliqua were FW, HW, WL and WW (Wing Width). Overall, FW and TL were more consistent predictors of mating success. In conclusion, female choice seems to suggest multivariate selection, confirming that overall body size (expressed as pupal diameter, which is highly correlated with weight) is not a decisive factor in male mating success in these two species. However, morphological traits such as FW, HW, TL, WL and WW may be relevant in mating preference of wild female.

The quality of biological control agents used in augmentative releases may be affected by rearing conditions due to inbreeding or laboratory adaptation, or to phenotypic effects of the rearing environment. We hypothesized that individuals from a wild population would be in better body condition and kill more prey than individuals from a commercially produced population. We caught wild Orius majusculus (Reuter) in a maize field and compared their initial body mass, survival, and prey reduction capacity to commercially produced O. majusculus. Predation capacity and survival were compared in short-term Petri dish tests with Frankliniella tenuicornis (Uzel) thrips, Ephestia kuehniella (Zeller) moth eggs, or Rhopalosiphum padi (L.) aphids as prey, and in longer-term outdoor mesocosms containing live seedling wheat grass with thrips or aphids as prey. Wild-caught O. majusculus were typically heavier and overall had higher survival during tests than commercially produced O. majusculus. Females were heavier than males and typically killed more prey. However, we found no difference between wild-caught and commercially produced individuals on prey reduction, neither in Petri dishes nor in mesocosms. Our study suggests that commercially produced O. majusculus have lower body condition than wild O. majusculus due to their lower body mass and survival, but that this does not have any negative effect on the number of pest prey killed over the timelines and conditions of our tests. Commercially produced O. majusculus thus did not have a lower impact on pest prey numbers than wild-caught individuals and therefore had similar biological control value under our study conditions.

Tephritid fruit flies in the genus Rhagoletis bridge between predictable periods of fruit availability by becoming dormant. To cope with acyclic unpredictable events (e.g., frost, mast seeding, etc), a proportion of the population can undergo prolonged dormancy. In the case of walnut infesting Rhagoletis, host plant-derived cues such as juglone soil concentration vary seasonally in predictable patterns. Here, we examined the effects of host plant parts and derived compounds on emergence rates and dormancy duration of Rhagoletis completa (Cresson), Rhagoletis zoqui (Bush) (Diptera: Tephritidae), and associated parasitoids. Pupae of both species were exposed to walnut leaves, fruit, or fruit and leaves and compared to a control. In a second experiment, R. zoqui were exposed to 10 mg l−1 of juglone applied to pupation medium during four consecutive 4-week time periods under variable combinations of temperature and frequency of exposure. Overall, the presence of fruit resulted in greater overwintering survival of R. completa but had no effect on the duration of dormancy of either fly species. Application of juglone over two consecutive periods produced greater mortality of R. zoqui than the control. Three parasitoid species emerged from R. completa and one from R. zoqui. Duration of dormancy for parasitoids was longer than that of fly hosts. Regardless of treatment, 13.3–18.4% of R. completa pupae and 1.3–2.8% R. zoqui engaged in prolonged (>year) dormancy. Our results indicate that host plant derived cues have little or no effect on survival and duration of dormancy of walnut infesting Rhagoletis, and at the tested concentration juglone is toxic to R. zoqui pupae. Testing the effect of juglone at lower concentrations is necessary to rule out its role as an environmental cue for regulation of dormancy. So far, host plant fruiting phenology appears to play a greater role than host plant derived cues in selecting for fly eclosion times.

The majority of plant viral disease is transmitted and spread by insect vectors in the field. The small brown planthopper, Laodelphax striatellus (Fallén), is the only efficient vector for rice black-streaked dwarf virus (RBSDV), a devastating plant virus that infects multiple grain crops, including rice, maize, and wheat. Adenosine triphosphate (ATP)-binding cassette (ABC) transporters participate in various biological processes. However, little is known about whether ABC transporters affect virus infection in insects. In this study, RBSDV accumulation was significantly reduced in L. striatellus after treatment with verapamil, an effective inhibitor of ABC transporters. Thirty-four ABC transporter genes were identified in L. striatellus and expression analysis showed that LsABCF2 and LsABCG9 were significantly upregulated and downregulated, respectively, after RBSDV infection. LsABCF2 and LsABCG9 were expressed during all developmental stages, and LsABCG9 was highly expressed in the midgut of L. striatellus. Knockdown of LsABCF2 promoted RBSDV accumulation, while knockdown of LsABCG9 suppressed RBSDV accumulation in L. striatellus. Our data showed that L. striatellus might upregulate the expression of LsABCF2 and downregulate LsABCG9 expression to suppress RBSDV infection. These results will contribute to understanding the effects of ABC transporters on virus transmission and provide theoretical basis for virus management in the field.

Chickpeas (Cicer arietinum L.) belong to the Fabaceae family and are one of the most grown crops in the world and an important source of protein for humans. Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae) is a polyphagous pest that causes significant crop damage. The objective of this study was to examine antibiosis to S. frugiperda in chickpea genotypes. The following genotypes were studied: Jamu 96 and Blanco Sinaloa 92 (Mexico); Nacional 29 (Cuba); BG 1392 (Spain), and BRS Kalifa, BRS Cristalino, BRS Toro, Nacional 27, 004UP, 003UP, BRS Cícero, and BRS Aleppo (Brazil). The chickpea genotypes influenced the biological parameters of S. frugiperda, of which larval period, larval weight, and pupal period were most affected. Nacional 29 caused high mortality in the larval and pupal stages of S. frugiperda. The larvae on BRS Aleppo had the longest larval stage, lowest weight, and longest pupal stage. The genotypes Nacional 29, Nacional 27, and BRS Cícero showed antibiosis resistance to S. frugiperda. These genotypes could be used as a source of resistance to S. frugiperda in conjunction with other methods of pest control in integrated pest management programs for chickpea crops. These resistant genotypes could also be used as donor sources in breeding programs for insect resistance.

Insect crop pests are a major threat to food security in sub-Saharan Africa. Configuration of semi-natural habitat within agricultural landscapes has the potential to enhance biological pest control, helping to maintain yields whilst minimising the negative effects of pesticide use. Fall armyworm (Spodoptera frugiperda, J. E. Smith) is an increasingly important pest of maize in sub-Saharan Africa, with reports of yield loss between 12 and 45%. We investigated the patterns of fall armyworm leaf damage in maize crops in Ghana, and used pitfall traps and dummy caterpillars to assess the spatial distribution of potential fall armyworm predators. Crop damage from fall armyworm at our study sites increased significantly with distance from the field edge, by up to 4% per m. We found evidence that Araneae activity, richness and diversity correspondingly decreased with distance from semi-natural habitat, although Hymenoptera richness and diversity increased. Our preliminary findings suggest that modifying field configuration to increase the proximity of maize to semi-natural habitat may reduce fall armyworm damage and increase natural enemy activity within crops. Further research is required to determine the level of fall armyworm suppression achievable through natural enemies, and how effectively this could safeguard yields.

The influences of different plants on herbivores have recently attracted research interest; however, little is known regarding the effects of wild, local and cultivated varieties of the same plant from the same origin on herbivores. This study aimed to examine the effects of different tobacco varieties from the same origin on the oviposition preference and offspring performance of Spodoptera litura. We selected two wild (‘Bishan wild tobacco’ and ‘Badan wild tobacco’), two local (‘Liangqiao sun-cured tobacco’ and ‘Shuangguan sun-cured tobacco’) and two cultivated (‘Xiangyan No. 5’ and ‘Cunsanpi’) tobacco varieties from Hunan Province, China. We found that female S. litura varied in oviposition preferences across the tobacco varieties. They preferred to lay eggs on the cultivated varieties, followed by the local varieties, with the wild varieties being the least preferred. Furthermore, different tobacco varieties significantly influenced the life history parameters of S. litura. Survival rate, pupal weight, emergence rate and adult dry weight decreased in the following order: cultivated varieties > local varieties > wild varieties. Conversely, the pupal stage and development period decreased in the following order: wild varieties > local varieties > cultivated varieties. Therefore, we conclude that wild tobacco varieties have higher resistance to S. litura than cultivated and local varieties, reflecting the evolutionary advantages of wild tobacco varieties.

Endoparasitoid species devoid of symbiotic viruses inject secretions derived from their reproductive glands into their hosts during parasitism in order to avoid various immune responses of their hosts. Pimpla turionellae L. (Hymenoptera: Ichneumonidae) is an endoparasitoid that lacks polydnaviruses, and its venom has previously been shown to paralyze the host Galleria mellonella (Lepidoptera: Pyralidae) and suppress its immune reactions to ensure the egg survival. The present study demonstrates that another female-injected factor calyx fluid extracted from the P. turionellae ovary is also responsible for the suppression of G. mellonella immunity. The total hemocyte counts of G. mellonella decrease after treatment with calyx fluid in a concentration-dependent manner. Significant reductions in cell viability are also observed at all calyx fluid doses both in vivo and in vitro. The analyses of the beads injected into the insects as encapsulation targets revealed that the number of encapsulated beads reduced significantly compared to controls post-calyx fluid injection. The injection of the highest calyx fluid dose (1 female equivalent calyx) is sufficient to completely inhibit the strong encapsulation and melanization reactions of the last instar larvae 24 h post-injection. These results demonstrate that P. turionellae calyx fluid is required to regulate host immunity for successful parasitization.

Florida red scale, Chrysomphalus aonidum (L.) is a species of armored scales, which attacks citrus crops. Biological control, particularly ladybeetles, are critical for its management in citrus production systems. We evaluated predation of C. aonidum by adult and larvae (3rd–4th instar) of the metallic blue ladybeetle, Curinus coeruleus. C. coeruleus were tested against C. aonidum in three separate treatments on Valencia orange leaves in Petri-dish arenas (1) individuals with armor intact, (2) individuals with armor removed, and (3) mix of individuals with armor intact or removed, to determine if armor inflicts distraction to predator consumption of scale and impact. Within 24 h of exposure to C. aonidum, adult beetle consumption rate averaged 64–68% in the two treatments containing all or half of the individuals with armor, compared to 100% in the treatment with armor removed. The consumption rate in the former two treatments increased to 83–89% within 72 h. Larval consumption of C. aonidum with armor intact was 25% at 24 h and 41% at 72 h, compared to 92–100% in the treatment with armor removed. The adults resulting from the larvae developed on C. aonidum with the armor intact or between the diets of armor intact or removed consumed more scales without armor than with armor. Significant consumption of C. aonidum by adults and larvae of C. coeruleus indicates that it is an efficient predator of this pest species. These novel findings suggest that this predator could be useful for suppressing C. aonidum populations in citrus production systems, particularly in habitats where both species are established such as Florida.

Spodoptera littoralis (Boisd) is globally recognized as a destructive polyphagous insect pest of various crops in the world. It is commonly managed by chemical pesticides, which can cause deleterious effects such as environmental pollution, toxicity to non-target organisms and the emergence of secondary pests. Hence, investigations into alternative pest control strategies such as the use of resistant host plant cultivar against S. littoralis is important. This study aimed to explore the nutritional performance of S. littoralis larvae in dependence on total anthocyanin, flavonoid, and phenol levels across 11 bean cultivars (Phaseolus and Vigna spp.) under laboratory conditions. The results revealed that the Mashhad cultivar accumulated the highest amount of total phenols (13.59 mg ml−1), whereas Yaghout and Arabi cultivars posed the lowest total phenols contents (1.80 and 1.90 mg ml−1, respectively). Across larval instars (third to sixth), the highest consumption index and relative consumption rate were recorded on the Mashhad cultivar. The lowest values of efficiency of conversion of ingested food and the efficiency of conversion of digested food of total larval instars were detected in the larvae which were reared on the Mashhad cultivar. Likewise, the lowest value of the index of plant quality (IPQ) was obtained in the Mashhad cultivar; however, IPQ was figured out at the highest level in the Arabi cultivar. Our findings show that the differential accumulation of secondary metabolites would change the nutritional quality of plants for S. littoralis. Based on the findings, the Mashhad cultivar may serve as a candidate for either integrated pest management or breeding programs aiming at controlling this pest.

Non-crop plant diversity plays a fundamental role in the conservation of predatory mite (PM) and can be proposed as a banker plant system (BPS). BPSs provide plants that host natural enemies in greenhouses or field crops and may improve the efficiency of biological control. The aim of this study was to investigate if a diverse plant composition could be a suitable BPS for PMs in strawberry crops. A plant inventory characterized 22 species of non-crop plants harboring PMs. The most abundant PMs, in decreasing order, were Neoseiulus californicus, Neoseiulus anonymus, Euseius citrifolius, and Euseius concordis. PMs were randomly distributed among plants. We also found specific associations of Phytoseiidae species and phytophagous or generalist mites on plants. Due to this, four species were deemed suitable as banker plants: Capsicum sp., Leonurus sibiricus, Solanum americanum, and Urochloa mutica. Moreover, these plants combined a high PMs density and a low occurrence or absence of pest-mites. This study suggests shifting the traditional view that BPSs are composed of a limited number of species to use plant assemblages. This contributes to both conservation and augmentative biological control.

The giant sugarcane borer, Telchin licus, has been reported as an economically important sugarcane pest in Colombia; however, its taxonomic status has been scarcely investigated and previous reports offer an ambiguous characterization of both the immature and adult stages. The objective of this work is to identify Telchin species affecting sugarcane and alternative hosts in different departments of the country by integrating molecular analysis and conventional morphology. To date, T. licus has been found in the departments of Caquetá, Casanare, and Meta, while T. atymnius has been found in Antioquia, Caldas, Nariño, and Valle del Cauca. Sugarcane, Musaceae, and Heliconiaceae have been found to be hosts to both species. Additionally, the species T. cacica has also been registered in the department of Nariño, affecting heliconias and plantains. Genetic variation within the species allowed differentiation at the molecular level of subspecies of T. licus and T. atymnius, confirming that the subspecies present in Colombia are T. licus magdalena, T. atymnius humboldti, and T. atymnius atymnius. The haplotype diversity of populations is closely related to their geographical distribution, indicating low gene flow between populations and possible speciation inside the country. Analysis of genetic variance showed significant differences among and within T. atymnius populations, which may suggest a high genetic structure along the regions where it is found and the possible presence of additional subspecies to those previously reported. To understand the geographical and environmental conditions that determine the pest's distribution in Colombia, this information needs to be complemented with ecological considerations of possible geographical isolation and association of alternative hosts.

Mosquitoes are vectors of several diseases of medical concern such as malaria or dengue and can also negatively affect tourism and the life-quality of the neighbourhood. The species Aedes mariae (Sergent and Sergent, 1903) is a poorly studied mosquito that breeds in rock-pools of the Mediterranean coast. General Linear Mixed Models (GLMM) were used to determine drivers affecting the presence and abundance of this species. Abiotic and biotic factors were recorded in rock-pools with the presence of Ae. mariae sub-adults across a supralittoral area of Majorca Island (Balearic Islands, Spain) from July 2018 to June 2019. We tested how abiotic factors affected the presence of larvae, while the biotic factors were used to check their effect on larvae abundance. human landing collection was also conducted to assess the adult activity of this species. Valuable data were recorded to improve our knowledge about the bioecology of Ae. mariae in a touristic area of the island of Majorca. Salinity and pH were the most explanatory variables for the presence of Ae. mariae larvae. The presence of Posidonia oceanica (L.) Delile 1813 leaves negatively affected the abundance of Ae. mariae larvae while the presence of other fauna enhanced it. Adult females of Ae. mariae were active for 26 min after sunset in June and its host-seeking activity decreased during autumn months. Control methods against this species should be focussed on rock-pools and planning treatments according to tides, waves and precipitation.

Temperature strongly impacts the rates of physiological and biochemical processes, which in turn can determine the survival and population size of insects. At low temperatures performance is limited, however, cold tolerance and performance at low temperature can be improved after short- or long-term acclimation in many insect species. To understand mechanisms underlying acclimation, we sequenced and compared the transcriptome of the blowfly Chrysomya megacephala under rapid cold hardening (RCH) and long-term cold acclimation (LCA) conditions. The RCH response was dominated by genes related to immune response, spliceosome, and protein processing in endoplasmic reticulum with up-regulation during recovery from RCH. In contrast, LCA was associated with genes related to carbohydrate metabolism and cytoskeleton branching and stabilizing. Meanwhile, mRNA levels of genes related to glycerophospholipid metabolism, and some heat shock proteins (Hsps) were collectively up-regulated by both RCH and LCA. There were more genes and pathway adjustments associated with LCA than RCH. Overall, the transcriptome data provide basic information of molecular mechanisms underpinning the RCH and LCA response. The partly independent molecular responses to RCH and LCA suggest that several avenues for manipulating cold performance exist and RCH might be more effective as it only triggers fewer genes and affects the general metabolisms less. These observations provide some appropriate methods to improve cold tolerance of C. megacephala, and hold promise for developing an extended use of mass-reared C. megacephala with better cold performance as a pollinator of crops at low temperatures.