Entomologia Experimentalis et Applicata最新文献

Effects of glyphosate and glyphosate-based herbicide on learning and memory of the buff-tailed bumblebee (Bombus terrestris) – K. Kaakinen, S. Ramula, O. J. Loukola & M. Helander (https://doi.org/10.1111/eea.13418).

Metamasius callizona (Chevrolat) (Coleoptera: Curculionidae) is an invasive weevil destroying Tillandsia utriculata L. (Bromeliaceae) populations in Florida, USA. A T. utriculata population in Belize coexists with M. callizona without adverse effects. Tillandsia utriculata and M. callizona from Belize and Florida were studied in the laboratory to determine how Belize T. utriculata can coexist with Belize M. callizona, using Florida and Belize T. utriculata, as well as pineapple, Ananas comosus (L.) Merr. (Bromeliaceae), as host plants. Florida M. callizona on pineapple leaves produced more eggs per female per day and had a shorter developmental time and pupation period, as well as a smaller adult width, than Belize M. callizona. Florida and Belize weevils did not differ significantly in rates of egg hatch, pupation, and adult emergence. Florida M. callizona laid similar numbers of eggs per day on Florida and Belize T. utriculata. Egg hatch rates were similar on pineapple and Florida and Belize T. utriculata. Pupation rates were similar on pineapple and Florida T. utriculata leaves; no larvae on Belize T. utriculata attained fourth instar. Field and laboratory observations revealed that Belize and Florida M. callizona mined Belize T. utriculata without destroying the meristem, allowing plants to survive, but Belize M. callizona destroyed the core of pineapple tops. Soluble solids were greatest in pineapple and least in Belize T. utriculata. Leaf toughness was greatest in pineapple and least in Florida T. utriculata. Metamasius callizona biology and behavior and T. utriculata plant characteristics may drive the severity of weevil damage on populations of T. utriculata. The discovery of a T. utriculata population in Belize coexisting with M. callizona offers a possible way to control M. callizona in Florida.

Sericulture, the practice of rearing silkworms for the production of silk, is an essential agro-based industry in several countries. However, silkworms are susceptible to a variety of diseases caused by viruses, bacteria and parasites, which may have a significant negative impact on global silk production. Traditional methods of pathogen identification, such as microscopy and laboratory culturing, have limitations in terms of accuracy and efficiency. The development of molecular techniques for pathogen identification has revolutionised the field of sericulture over the last decade. Genomic DNA and RNA-based molecular techniques allow for the rapid and accurate detection of disease-causing pathogens in silkworms. Molecular diagnosis has several advantages over traditional methods, including increased sensitivity and specificity, shorter turnaround time and the ability to detect pathogens that are difficult to culture or visualise under a microscope. Molecular techniques have been applied to detect several important pathogens of silkworms, including Nosema sp., nucleopolyhedrovirus, cypovirus, iflavirus and bidensovirus. The use of molecular diagnostics in sericulture is immensely important as the demand for high-quality silk increases globally and the assessment of emerging pathogens associated with crop loss is essential. Major advancements in the improvement and application of molecular methods for diagnosing widespread silkworm pathogens are discussed.

Fruit fly pests (Diptera: Tephritidae) are a serious problem for fruit production and for local and international trade. Biological control is increasingly included as a pest control tool within integrated pest management (IPM) programmes, seeking to reduce pesticides and improve fruit quality. Ceratitis capitata Wiedemann, the Mediterranean fruit fly (medfly), is probably the most damaging fruit fly pest, with a global distribution and more than 200 host species. The solitary larval endoparasitoid Diachasmimorpha longicaudata Ashmead (Hymenoptera: Braconidae) is a biocontrol agent widely used against Tephritidae fruit fly pests. Previous studies showed that female wasps locate host larvae using visual, mechanical, and chemical cues. Here, we investigated the chemical basis of female parasitoid attraction to cues that guide D. longicaudata to the host, and thus unveil volatile organic compounds that might be used in IPM programmes. Female orientation to chemical cues was tested in a Y-tube olfactometer, where attraction to C. capitata-infested oranges, oranges with residues of larval activity, oranges infected with a green mould, and overripe oranges was confirmed. Volatiles from all these types of fruit were collected and used in gas chromatography-electroantennographic detection (GC-EAD) and GC-mass spectrometry (MS) analyses. These studies allowed us to identify six candidate compounds that were present in all treated oranges but not in the control fruit (ripe and uninfested oranges): D-limonene, acetophenone, linalool, nonanal, decanal, and eugenol. Electroantennography (EAG) showed that acetophenone, nonanal, and decanal triggered dose-dependent responses, suggesting a relevant role in the process of host finding. Although responses to D-limonene, linalool, and eugenol were independent of the dose, they could be involved in host location in areas with high probability of host presence. The fact that these six compounds are shared by the four behaviourally attractive sources opens new possibilities for the development of novel tools to improve biocontrol programmes.

The polyphagous shot hole borer (PSHB), Euwallacea fornicatus Eichhoff (Coleoptera: Curculionidae, Scolytinae), is a significant tree-killing pest recently introduced into South Africa. Many native trees in urban settings are susceptible to infestation, but the presence of PSHB in natural ecosystems is unstudied. The presence and drivers of PSHB colonization in 1682 trees of 68 species were evaluated in 51 plots across a native Afrotemperate forest complex in South Africa. Breeding colonies of PSHB were found in six native species (breeding hosts). An additional 11 species did not contain PSHB colonies but hosted its mutualistic fungus Fusarium euwallaceae Freeman et al. (Hypocreales: Nectriaceae). Invasibility increased when plots were closer to the urban infestation border, further away from surface water, and when containing a larger number of breeding hosts. Invasibility decreased with an increase in tree species richness. Polyphagous shot hole borers were found in climax forest distant to urban areas at sites frequented by tourists. The severity of infestation of trees increased with an increase in host diameter, breeding host abundance, and infested tree abundance. Probability of infestation increased with an increase in the number of infested trees. Infested trees were not spatially clumped. Instead, PSHB preferentially selected eight of the 17 native host species. And the data suggest that larger trees of these species may be more susceptible to PSHB. Eight species were infested at random and two were infested seemingly accidentally. Infestations increased more rapidly on larger trees and on those surrounded by a high abundance of breeding hosts. This study confirms that Afrotemperate forests are highly susceptible to invasion by PSHB. Direct anthropogenic impact had no discernible effect on infestations, but humans aided spread of PSHB to distant sites. Halting movement of contaminated wood is important. Management of PSHB should focus on highly infested areas and trees as these increase the likelihood of further and more severe infestations.

Plants produce various phytochemicals against herbivory, but phytophagous insects have encountered phytochemicals in the co-evolutionary history between plants and insects. Selection pressure exerted by phytochemicals triggers a preadaptation to insecticide resistance in insect pests that is due to detoxification systems that are common to phytochemicals and insecticides in the insect's body. We investigated the interaction between the host plant resistance of rice cultivars and the brown planthopper, Nilaparvata lugens (Stål) (Hemiptera: Delphacidae). Forty brown planthopper resistance gene loci (BPHs) that are related to phytochemicals in various cultivars of rice inhibit feeding by N. lugens, but this planthopper has developed virulence to resistant rice cultivars possessing some genes. Nilaparvata lugens has also developed resistance to some insecticides as a rapid adaptation to human-driven selection. We tested the hypothesis that the evolution of insects' resistance to an insecticide is promoted by their encounters with phytochemicals. We compared the virulence of imidacloprid-resistant and control N. lugens strains toward seven rice cultivars that possess different genes, and we observed that the imidacloprid-resistant N. lugens had reduced virulence to three rice cultivars, Rathu Heenati (BPH3, BPH17), Babawee (BPH4), and Balamawee (BPH27, three quantitative trait loci), meaning that the development of imidacloprid resistance has a negative impact on the virulence of N. lugens to three cultivars. Our results indicate trade-offs rather than a co-relationship between the evolution of insecticide resistance and encounters with host plant defense.

The cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), is a major insect pest of various agricultural crops worldwide. In this study, the effects of eight sorghum [Sorghum bicolor (L.) Moench, Poaceae] cultivars (Payam, Pegah, Sepideh, Spidfid, Kimia, KGS₂₃, KFS₂, and KFS₁₈) on life table parameters, feeding performance, and activities of digestive enzymes in H. armigera were assessed under laboratory conditions. The insects were fed grains of the eight cultivars. Furthermore, the phytochemicals starch, proteins, flavonoids, and phenolic compounds in the grains were quantified to investigate their relationship with ecological and physiological parameters in H. armigera. Our results revealed that H. armigera had the shortest development time when reared on cv. Sepideh and the longest development time when reared on cv. Payam. The insects reached the highest and lowest intrinsic rate of increase (r) on cv. Sepideh and Payam, respectively. The relative growth rate (RGR) and efficiency of conversion of digested food (ECD) of larvae were highest and lowest on cv. Sepideh and Payam, respectively. Larval proteolytic activity was highest on cv. KFS₁₈ and lowest on cv. Sepideh. Concerning phytochemicals, protein content was highest in cv. KFS₁₈ and lowest in cv. Payam and KGS 23. Total phenolic levels were highest in cv. Payam and lowest in cv. Sepideh. According to the correlation analysis, overall, plant protein content was negatively correlated with insect development time, but positively correlated with pupal weight and r. Total phenolic content was positively correlated with insect development time, and negatively correlated with r and RGR. Cluster analysis indicated that cv. Sepideh was the most susceptible host, whereas cv. Payam was the most resistant. Therefore, cv. Payam may be a candidate for use in integrated pest management (IPM) against H. armigera.

The decline of insect pollinators is a global concern, and the use of pesticides has been identified as a potential cause for it. Glyphosate-based herbicides (GBHs) are the world's most used pesticides, but until recent years they have been claimed to be safe for non-target organisms, such as pollinators. Using controlled arena experiments, we investigated the effects on the learning and long-term memory of buff-tailed bumblebees, Bombus terrestris (L.) (Hymenoptera: Apidae), of a single field-realistic dose of glyphosate, both in its pure form and as a commercial herbicide (Roundup Gold) containing the active ingredient (a.i.) glyphosate and other co-formulants. We found that glyphosate in its pure form caused deterioration in the learning ability of bumblebees in a 10-color discrimination experiment; the glyphosate-treated bees discriminated colors over 10% worse than the untreated control bees. However, the commercially used GBH (Roundup Gold) had no observable effect on the learning ability of the bumblebees, despite the fact that this herbicide contained the same amount of glyphosate as its pure form. These findings shed light on the potential risks associated with agrochemicals previously considered safe for pollinators and emphasize the need for comprehensive risk assessments of pesticides, including evaluations of cognitive functions in pollinators. Therefore, we propose that future pesticide testing should incorporate broader assessments to ensure the safety of pollinators in agricultural landscapes.

Understanding of functional responses (i.e., changes in predator feeding rates with prey density) of key predators to different crop pest stages is critical to strengthening biological control, particularly in view of climate change and temperature variation. We investigated prey preferences of Coccinella septempunctata L. (Coleoptera: Coccinelidae) to egg and larval stages of a key brassicaceous pest of canola (Brassica napus L., Brassicaceae), the diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae). First, laboratory choice and no-choice bioassays tested the hypotheses that C. septempunctata accepts and differentially prefers two prey developmental stages (eggs and larvae). Then, C. septempunctata larvae and adults were exposed to six densities of P. xylostella eggs over 24 h in functional response bioassays that determined the number of eggs consumed. Finally, the functional response bioassays were repeated with larval prey and extended with three temperature regimes: 10, 22 and 32 °C. In both choice and no-choice assays, C. septempunctata adults and larvae consumed more P. xylostella larvae than eggs. The functional response of C. septempunctata depended on predator developmental stage and temperature, with reduced handling time and increased attack rates and consumption under warmer conditions. At 10 and 22 °C, the functional responses of both C. septempunctata larvae and adults were of Type II, i.e., rates of prey consumption increase at decelerating rates and then plateau with increasing prey density. Our study demonstrates that both larvae and adults of C. septempunctata can consume high numbers of eggs and early instar P. xylostella larvae; these responses are temperature-dependent with increased consumption rates at higher temperatures. This may lead to improvements in management of P. xylostella in canola.

Dragonflies and damselflies are excellent bioindicators of the quality of both aquatic and terrestrial ecosystems. In our study, we assessed the usefulness of metric and meristic morphological traits as environmentally friendly and cost-effective indicators of the integrative ecological quality of watercourses. Our study species of choice was the damselfly banded demoiselle, Calopteryx splendens (Harris) (Odonata: Calopterygidae). Adult C. splendens specimens were collected at three study sites along the trophic gradient of the Tisza River in Hungary and Ukraine. Body and abdomen length, head width, and distances between wing landmarks were assessed as metric traits, and the number of wing cells as meristic traits. The concentration of chlorophyll-a was used to classify the three study sites into having a low, intermediate, and high trophic condition based on earlier studies. Significant differences were found along the trophic gradient based on the measured metric and meristic traits. Especially, insects from the site with the highest trophic condition had the largest body length, head width, and distances between wing landmarks, as well as the highest number of cells in the fore wings. There were also differences between males and females, but we did not find differences in fluctuating asymmetry (FA), i.e., differences between the left and the right wings. These results indicated that the morphological traits of adult banded demoiselles could be indicative of the environmental quality of a watercourse.