Search Results (152)

Oviposition site selection is critical for mosquito population dynamics. Gravid mosquitoes rely on chemical cues to identify suitable breeding habitats. However, the sensory mechanisms governing this behavior in Anopheles stephensi remain poorly understood. Here, we examined the role of indole, a microbial volatile associated with aquatic environments, in oviposition site choice and assessed the involvement of sensory organs in its detection. In two-choice oviposition assays, water conditioned with first-instar larvae attracted gravid females (OAI = 0.56). In contrast, water from fourth-instar larvae was repellent (OAI = −0.20), consistent with avoidance of suboptimal, resource-depleted habitats. Single indole cue elicited strong oviposition attraction across a broad concentration range (0.5–50 µM), with no clear dose–response relationship. Surgical ablation of antennae and maxillary palps did not abolish indole-mediated preference but significantly reduced behavioral variability, suggesting that these structures modulate, rather than solely mediate, indole detection. Reanalysis of transcriptomes of antennae, maxillary palps, and legs in An. gambiae and An. coluzzii, along with quantitative RT-PCR in An. stephensi revealed the expression of chemosensory genes (including Obp1, Obp13, Obp25, Obp71, Or2, and Or10) in the legs, suggesting a potential role for leg chemosensation in oviposition decisions. These findings underscore the complexity of chemoperception in mosquito habitat assessment. Full article

Proximate visual cues play a crucial role for flies (Order: Diptera) in locating suitable foraging and oviposition sites. This study examined the behavioural responses of two sheep myiasis-causing blowfly species in Australia, Lucilia cuprina (Wiedemann) and Chrysomya rufifacies (Macquart), to six different reflectance levels of green and yellow hues. Both species were influenced primarily by reflectance intensity and proximity to the light source. Lucilia cuprina displayed a nonsignificant preference for moderate yellow (p = 0.25), whereas Ch. rufifacies showed a significant attraction to moderate green (p = 0.004) when presented with a two-choice comparison between moderate green and yellow. When exposed to three reflectance levels under each hue, both species responded most strongly to mid-range intensities in green but not yellow, with no significant differences observed among light and dark shades (p > 0.05). Zonal analyses revealed a significant aggregation of individuals near the light source (Zone C; p < 0.05), indicating that spatial orientation cues may be stronger determinants of attraction. Overall, L. cuprina was more responsive to moderate yellow and Ch. rufifacies to moderate green, but both species were predominantly guided by light-related spatial and intensity cues. These findings provide valuable insight into the visual ecology of blowflies and may be useful in optimising colour and reflectance parameters in the design of future commercial fly traps. Full article

Zeugodacus tau (Walker) is a major invasive pest that targets cucurbitaceous plants and other economically significant crops, causing substantial yield and quality losses. The pest’s method of infesting the fruit, however, limits the efficacy of conventional chemical control strategies. This study comprehensively evaluates the insecticidal efficacy of seven insecticides from two key classes—macrolides and neonicotinoids—against various developmental stages of Z. tau. Additionally, it investigates the distribution and degradation patterns of pesticide residues on sponge gourd. Laboratory toxicity tests showed notable differences in sensitivity among the three pest stages. Larvae were the most sensitive to insecticides, followed by adults, with eggs being relatively resistant. Four macrolide insecticides showed high activity against both adults and larvae, while three neonicotinoids displayed low activity against eggs, larvae, and adults of Z. tau. Field residue trials using common recommended dosages demonstrated rapid degradation of pesticide residues on sponge gourd, with residue levels dropping below the national maximum residue limits (MRLs) within 2 to 24 h after application. Further results indicated that pesticide residues accumulated mainly on the peel, with low or undetectable levels in the flesh. Among the macrolide insecticides, residues were nearly undetectable, whereas neonicotinoids, due to their systemic nature, sometimes showed trace residues in the fruit flesh. Oviposition hole measurements revealed an average depth of 0.57 ± 0.29 cm, just beneath the skin, with the hole’s structure effectively protecting the eggs laid by females. Based on the comprehensive analysis of insecticide toxicity and residue degradation, control strategies should primarily target adults. Macrolide insecticides, which have low residue risks and high efficacy against both adults and larvae, are recommended as the preferred option for management. This study, considering the unique damage characteristics of Z. tau, offers valuable insights into chemical control strategies, focusing on insecticide sensitivity at different life stages, residue distribution, and degradation, providing important references for the scientific use of pesticides and the optimization of pest management approaches. Full article

Insect infestation poses a significant threat to global agriculture by impairing plant growth and reducing crop yields. The western flower thrip (WFT) causes substantial damage through both direct feeding and transmission of plant viruses. Although the jasmonic acid (JA) signaling pathway is known to participate in plant defense against WFTs, the underlying molecular mechanisms in non-model crops such as peppers, remain largely elusive. This study investigates the role of suppressor of prosystemin-mediated responses2 (Spr2) within JA-mediated defense against WFTs in pepper. Through an integrated approach employing virus-induced gene silencing (VIGS), transcription analysis, phytohormone quantification, insect behavior assays and life history investigations, we demonstrated that silencing CaSpr2 significantly reduced JA and JA-Ile accumulation, and led to a strong feeding preference of WFTs for CaSpr2-silenced plants. Furthermore, the adult lifespan, survival rate, female fecundity, oviposition rate, and population parameters of WFTs were significantly improved on CaSpr2-silenced plants. Spr2 functions as an essential component within the JA signaling pathway, thereby playing a critical role in conferring resistance to WFTs in cultivated pepper. These findings provide profound insights and practical implications for breeding thrips-resistant cultivars in non-model plants, through genetic manipulation of JA signaling, offering a promising avenue for sustainable agricultural pest management. Full article

The codling moth (Cydia pomonella L.) is a major pest of pome fruits worldwide, guided by semiochemicals to locate hosts and oviposition sites. Quince (Cydonia oblonga Mill.), although less studied, is also affected by this pest. This study aimed to identify behaviorally active compounds for codling moth by characterizing the volatilome of quince cultivars. Volatile profiles were analyzed across four phenological stages (flowering, unripe, growth, and ripe fruit) using solid-phase microextraction and GC–MS. The cultivars evaluated were Champion, INTA 37, INTA 117, and INTA 147. Female oviposition behavior and neonate larval host choice were also assessed. Identified volatiles included esters, sesquiterpenes, monoterpenes, alcohols, aldehydes, and norisoprenoids. Among monoterpenes, limonene, consistently detected across all cultivars and stages, emerged as a key kairomone. Volatile composition varied across phenological stages, with the fruit growth stage exhibiting the highest diversity and abundance of compounds previously reported as behaviorally active. This pattern coincided with peak female oviposition and larval host selection. Females oviposited mainly on leaf surface, whereas during ripening, eggs were deposited on fruit lacking pubescence. Overall, INTA 147 was the most preferred cultivar. These findings highlight quince volatiles, particularly Limonene, as potential candidates for the development of semiochemical-based tools to improve codling moth management. Full article

Drosicha corpulenta (Hemiptera: Monophlebidae) is a major polyphagous pest affecting street and garden trees in arid regions of northern China, causing increasing damage in newly developed cities like Cocodala, Xinjiang. This study was conducted from 2024 to 2025 to investigate this pest’s life cycle, key damage periods, and spatial distribution in seven host plants, focusing on nymph emergence, female soil entry, and overwintering egg distribution. The results show that D. corpulenta has one generation per year, which overwinters as eggs. Nymphs emerge in early March, and male pupation occurs from mid-April to early May. Females mate after the third molt in early to mid-May and enter the soil to lay eggs from late May to early June, with consistent timing over two years. The suitability of the host varied significantly: Platanus × hispanica was the most preferred, with the highest daily nymph emergence of 840.8 individuals in 2024 and 1196.0 in 2025, followed by Prunus padus and five other plant species (Populus spp., Fraxinus chinensis, Styphnolobium japonicum, Pinus spp., and Malus spectabilis). Female soil entry reached a maximum on 23 May (979.8 individuals⁻¹ day⁻¹) and gradually decreased with increasing distance from the trunk. Overwintering eggs showed no obvious azimuthal bias, but were mainly concentrated near the trunk (0–30 cm) and in shallow soil (0–10 cm; 179.8 eggs per 100 g composite soil sample per sampling point), decreasing sharply in number with distance and depth. Both Taylor’s power law and Iwao’s regression confirmed the aggregated distribution. This study identifies key phenological stages, highly susceptible hosts, and the near-trunk shallow soil layer as critical for oviposition and overwintering and provides a basis for precise monitoring and targeted control in urban green spaces. Full article

Spodoptera eridania (Cramer, 1792) is increasingly reported from potato (Solanum tuberosum L., Solanaceae) in the Brazilian Cerrado, where infestations can cause substantial yield losses. Insecticides may alter the behavioral ecology of agricultural pests. The adaptability of S. eridania mediated by insecticides, especially regarding oviposition behavior, remains poorly understood. This study aimed to evaluate the spatial distribution and oviposition traits of S. eridania on potato plants under chlorfenapyr spraying. Egg masses were collected weekly, day after planting (DAP), totaling 322 collections up to the 91st DAP. Evaluations included the vertical plant strata (upper, middle and lower thirds), leaf surface (adaxial vs. abaxial), and density of scales covering egg masses (high, low, or absent). Results showed that nearly 90% of egg masses were deposited in the upper and middle thirds of the plants. Insecticide spraying modulated oviposition behavior because females preferred the middle third in treated plants, whereas oviposition predominated in the upper third of untreated plants. Moreover, under chlorfenapyr, 93.0 ± 1.2% of egg masses were placed on the abaxial surface. These findings highlight the role of insecticide-mediated behavioral shifts in shaping host-pest interactions and provide relevant insights for integrated pest management of S. eridania in potato field systems. Full article

This study presents the first successful laboratory rearing of Eremobelba eharai, with the establishment of a sustainable multigenerational breeding system. We document for the first time its complete morphological ontogeny across all developmental stages (from larva to adult) and characterize its life cycle. We supplement the original adult description with detailed morphological characterization and illustrations of the gnathosomatic structures, including the subcapitulum, palps, and chelicerae. Scanning electron microscopy showed that its surface is covered with a granular cerotegument. Under isolated rearing conditions, this species can complete the entire egg-to-egg developmental cycle. In addition, preliminary behavioral observations during rearing revealed preferences for dark environments, characteristic leg-shaking movements, and gregarious oviposition on active dry yeast particles, with no evidence of cannibalism. Full article

The South American tomato leaf miner, Tuta absoluta (Meyrick, 1917) (Syn.: Phthorimaea absoluta), is a pest of great economic importance worldwide. Although T. absoluta shows a strong preference for tomato, it can also attack potato, eggplant, and various wild solanaceous plants, thereby posing new challenges for pest control. To assess the adaptability of this pest to different potato varieties, an age-stage, two-sex life table method was used to determine the development, survival, reproduction, and key population parameters of the pest on six common potato varieties (Hezuo No. 88, Lishu No. 6, Weiyu No. 3, Zhongshu No. 5, Qingshu No. 9, and Qingshu No. 10) in China. The results showed that T. absoluta could complete its entire life cycle on all cultivars. However, key life history parameters varied significantly. On cultivars Qingshu No. 9 and Qingshu No. 10, the pest exhibited significantly prolonged preadult duration and total pre-oviposition period (TPOP), as well as reduced adult fecundity. In contrast, Hezuo No. 88 supported the highest intrinsic rate of increase (r) and net reproductive rate (R₀). The 60-day population projections further highlighted this contrast, showing that the T. absoluta population on Hezuo No. 88 increased by a factor of 4.26 and 3.52 times compared to that on Qingshu No. 9 and Qingshu No. 10, respectively. We conclude that cultivars Qingshu No. 9 and Qingshu No. 10 exhibit antibiosis resistance against T. absoluta. This study not only provides a theoretical foundation and candidate materials for breeding pest-resistant potato varieties, but also establishes a basis for IPM strategies against T. absoluta that are founded on host resistance. Full article

Tephritid flies employ visual and chemical cues to locate and assess suitable habitats, food sources, mating sites, and ovipositional resources. Bactrocera dorsalis and Zeugodacus tau are economically significant pests that infest a wide range of fruits and fleshy vegetables. Understanding their visual sensitivity is crucial for developing effective and ecologically friendly management strategies. Thus, in this study, we compare the responses of these two species to various visual stimuli across laboratory, greenhouse, and closed-orchard environments. Our experiments reveal that, across the tested physiological states, both species exhibit a preference for certain wavelengths in the laboratory, particularly 520 nm and 560 nm. In the greenhouse, green and yellow models captured significantly more females of both species. Z. tau females showed greater sensitivity to the yellow model than B. dorsalis females. Additionally, Z. tau showed a higher affinity for both spherical and cylindrical shapes, while B. dorsalis flies were only attracted to the spherical model. In a closed orchard area, traps modified according to the best-performing combination used in the laboratory and greenhouse (shape and light) increased the capture counts of both species over time, with Z. tau exhibiting greater visual attraction sensitivity than B. dorsalis. These findings provide a theoretical and scientific foundation for improving trapping techniques targeting these two species. Full article

Luteolin, as one of the flavonoids, has demonstrated repellent and toxic effects on various insect pests; however, its influence on thrips development and fecundity remains poorly understood. In this study, we investigated the toxicity of luteolin on the survival of a worldwide insect pest, the western flower thrips (WFT) (Frankliniella occidentalis Pergande), its effects on WFT feeding and oviposition preferences, and its sublethal impacts on development and fecundity. Results showed that both adult and nymphal WFT mortality rates increased with luteolin concentration. In choice assays, luteolin exhibited repellent effects on nymphal feeding and adult oviposition. At a sublethal concentration of 0.1 mg/mL, luteolin significantly shortened the adult lifespan, and reduced fecundity, intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rate (R₀), suppressing WFT population growth. This study demonstrates that luteolin has the potential to be developed as a botanical pesticide for thrips management, combining with toxic and reproduction-inhibiting activities. Full article

Invasive seed predators can severely affect the reproduction of long-lived trees, especially when host range expansion occurs. The beetle Specularius impressithorax (Chrysomelidae: Bruchinae), native to Africa, has become established in Hawaiʻi where it attacks the endemic coral tree (Erythrina sandwicensis; Wiliwili). Here, we report the infestation of an African coral tree (E. livingstoniana) by this beetle and assess its performance and oviposition patterns on native and non-native hosts. Field surveys showed that eggs were aggregated on both hosts but more abundant on E. sandwicensis than on E. livingstoniana. Laboratory assays revealed no difference in larva-to-adult survival between the two hosts, although adults emerging from E. sandwicensis were larger. Choice tests indicated no oviposition preference between the two Erythrina species, despite the larger seed size of E. sandwicensis. To explore potential host range expansion, trials were run on economic legumes with varying phylogenetic distance from Erythrina, which showed oviposition on peanut (Arachis hypogaea) with low but successful survival (10.3%), while no development occurred on broad bean or pigeon pea. More E. sandwicensis seeds germinated when infested by a single early-stage larva (70% germination) than when uninfested (20%), suggesting that minimal seed predation may facilitate germination because previously reported greater damage induced by infestation through adulthood reduces germination. Our findings highlight the ecological flexibility of an invasive bruchine, its potential to exploit other Faboideae plants, and the dual role of seed predators as both threats and facilitators of seed germination. These results have implications for conservation of endemic coral trees and for understanding invasion dynamics of shared seed predators. Additionally, we examined non-botanical substrate filled with seed powder for oviposition and compiled global host records of S. impressithorax to contextualize its host range expansion. Full article

Some special volatile organic compounds (VOCs) that significantly induce female oviposition preferences may be utilized to disrupt oviposition behavior and to enhance trapping strategies; such approaches offer a promising avenue for reducing insect infestations in stored commodities. Based on the significant differences in the oviposition preference of P. interpunctella among six normal-oleic varieties (NOPs), the key VOCs involved were further explored. Seventeen VOCs that may contribute the oviposition preference and that exhibited a high content in the peanut varieties were measured through electroantennogram (EAG) response measurements of female moths. The VOCs that produced significant EAG responses by the females were further assayed for behavioral responses by the Y-tube olfactometer method, wind tunnel tests, and a multiple-choice device for female oviposition. Heptanal, acetophenone, nonanal, hexanal, benzaldehyde, octanal, hexanoic acid, decanal, phenylacetaldehyde, and 1-octen-3-ol from peanuts elicited strong antennal EAG responses. These VOCs (especially heptanal, nonanal, hexanal, octanal, and decanal) attracted more females in both Y-tube olfactometer and wind tunnel assays and increased oviposition rates in oviposition tests. The results indicate that heptanal, decanal, octanal, nonanal, and hexanal may be utilized to develop oviposition attractants for female moths further. Full article

Drosophila suzukii is a key invasive pest, and infestation in peach orchards can lead to significant economic losses. This study monitored the spatial distribution and reproductive biology of D. suzukii in central Italy to inform integrated pest management (IPM) strategies. In the surveyed orchard, the pest exhibited multiple generations, with captures highest along mixed-species-orchard edges, highlighting these margins as potential hotspots for targeted mass trapping. Seasonal dissections of females revealed delayed ovarian development during winter, while maturation progressed during fruit ripening and post-harvest periods. This result provides relevant information on the likely timing of oviposition, useful for informing pest management. A laboratory oviposition trial on nectarines revealed a clear preference for healthy, mechanically damaged fruits, whereas fungal infection reduced the attractiveness. This suggests that field sanitation, especially the timely removal of damaged or fallen fruits, could reduce pest presence and inoculum for the following season. Overall, these findings offer practical insights to support sustainable IPM approaches against D. suzukii in peach production systems. Full article

Establishing refuges is a primary strategy for managing resistance in target pests against Bt maize. The larval feeding and dispersal, and adult oviposition behaviors of Spodoptera exigua (Hübner) on Bt and non-Bt maize plants are critical factors in determining optimal refuge configurations. This study employed laboratory and field experiments to evaluate the larval feeding and dispersal behaviors, as well as the oviposition preferences of S. exigua moths, on Bt (Cry1Ab + Vip3Aa19) and non-Bt maize plants. Results showed that as time of the choice test increased, the larval selection rate on Bt maize leaves declined progressively, with all instars (1st–5th) preferring to feed on non-Bt maize. After 48 h, the selection rates of larvae for non-Bt and Bt maize were 40.63–66.25% and 9.38–33.75%, respectively. Female moths exhibited no significant oviposition preference between Bt and non-Bt plants under undamaged conditions; however, when non-Bt maize was infested by the larvae, females preferentially oviposited on Bt maize plants (73.55%). Under the seed-mixture refuge pattern in field conditions, increasing the proportion of non-Bt maize significantly enhanced larval dispersal distances and facilitated larval transit damage between Bt and non-Bt plants. Our research clarifies the behavioral patterns of S. exigua on Bt and non-Bt maize, provides a scientific basis for optimizing refuge strategy to delay the development of resistance. Full article