Preference of the aphid Myzus persicae (Hemiptera: Aphididae) for tobacco plants at specific stages of potato virus Y infection

Potato virus Y (PVY) is a common pathogen affecting agricultural production worldwide and is mainly transmitted by Myzus persicae in a non-persistent manner. Insect-borne plant viruses can modify the abundance, performance, and behavior of their vectors by altering host plant features; however, most studies have overlooked the fact that the dynamic progression of virus infection in plants can have variable effects on their vectors. We addressed this point in the present study by dividing the PVY infection process in tobacco into three stages (early state, steady state and late state); delineated by viral copy number. We then compared the differential effects of PVY-infected tobacco (Nicotiana tabacum) plants on the host selection and feeding behavior of M. persicae. We used Y-shaped olfactory apparatus and electrical penetration graph (EPG) methods to evaluate host selection and feeding behavior, respectively. Interestingly, we found that PVY-infected plants at the steady state attracted more aphids than healthy plants, whereas no differences were observed for those at the early and late states. In terms of feeding behavior, intracellular punctures (closely related to PVY acquisition and transmission) were more abundant on PVY-infected tobacco plants at the early and steady states of infection than in uninfected plants. These results indicate that PVY-infected host plants can alter the host selection and feeding behavior of aphids in a stage-dependent manner, which is an important consideration when studying the interactions among host plants, viruses, and insect vectors. © 2019, Springer-Verlag GmbH Austria, part of Springer Nature

A meta analysis of spray drift sampling

There are many methods available for sampling spray drift, and a great variety of estimates of spray drift have been published. Available data on spray drift were collected from different studies and the measurements of spray drift were analysed to determine similarities and differences between the individual studies. Each of the methods varied significantly in their estimates of spray drift. This variation was due to many factors that differed between the published sources, such as environmental conditions, cropping system, equipment used and the tracer used. It is suggested that in order to compare drift measurements between published studies, measurement techniques and sampling distances must be standardised, and environmental conditions (humidity and temperature) should be restricted to within certain boundaries in the field, and controlled within artificial tests, unless, of course, the effect of this variable on drift is being examined

Up-regulation of cryptochrome 1 gene expression in cotton bollworm (Helicoverpa armigera) during migration over the Bohai Sea

Cryptochromes (CRYs) are flavoproteins and play a pivotal role in circadian clocks which mediate behavior of organisms such as feeding, mating and migrating navigation. Herein, we identified novel transcripts in Helicoverpa armigera of six isoforms of cry1 and seven isoforms of cry2 by Sanger sequencing. Phylogenetic analysis showed that the transcripts of cry1 and cry2 align closely with other insect crys, indicating within-species divergence of Hacry. A dn/ds analysis revealed that the encoding sequence of the cry1 was under purifying selection by a strong negative selection pressure whereas the cry2 was less constraint and showed a less strong purification selection than cry1. In general, Hacrys were more abundantly transcribed in wild migrating populations than that in laboratory maintained populations, and expression of the cry2 was lower than cry1 in all samples tested. Moreover, when compared with the migrating parental population, offspring reared in laboratory conditions showed a significant reduction on transcription of the cry1 but not cry2. These results strongly suggest that cry1 was more related to the migration behavior of H. armigera than cry2

Duplication and expression of horizontally transferred polygalacturonase genes is associated with host range expansion of mirid bugs

Background: Horizontal gene transfer and gene duplication are two major mechanisms contributing to the evolutionary adaptation of organisms. Previously, polygalacturonase genes (PGs) were independently horizontally transferred and underwent multiple duplications in insects (e.g., mirid bugs and beetles). Here, we chose three phytozoophagous mirid bugs (Adelphocoris suturalis, A. fasciaticollis, A. lineolatus) and one zoophytophagous mirid bug (Nesidiocoris tenuis) to detect whether the duplication, molecular evolution, and expression levels of PGs were related to host range expansion in mirid bugs. Results: By RNA-seq, we reported 30, 20, 19 and 8 PGs in A. suturalis, A. fasciaticollis, A. lineolatus and N. tenuis, respectively. Interestingly, the number of PGs was significantly positive correlation to the number of host plants (P = 0.0339) in mirid bugs. Most PGs (> 17) were highly expressed in the three phytozoophagous mirid bugs, while only one PG was relatively highly expressed in the zoophytophagous mirid bug. Natural selection analysis clearly showed that a significant relaxation of selection pressure acted on the PGs in zoophytophagous mirid bugs (K = 0.546, P = 0.0158) rather than in phytozoophagous mirid bugs (K = 1, P = 0.92), suggesting a function constraint of PGs in phytozoophagous mirid bugs. Conclusion: Taken together with gene duplication, molecular evolution, and expression levels, our results suggest that PGs are more strictly required by phytozoophagous than by zoophytophagous mirid bugs and that the duplication of PGs is associated with the expansion of host plant ranges in mirid bugs. © 2019 The Author(s)

Nutritional composition of honey bee food stores vary with floral composition

Sufficiently diverse and abundant resources are essential for generalist consumers, and form an important part of a suite of conservation strategies for pollinators. Honey bees are generalist foragers and are dependent on diverse forage to adequately meet their nutritional needs. Through analysis of stored pollen (bee bread) samples obtained from 26 honey bee (Apis mellifera L.) hives across NW-England, we quantified bee bread nutritional content and the plant species that produced these stores from pollen. Protein was the most abundant nutrient by mass (63%), followed by carbohydrates (26%). Protein and lipid content (but not carbohydrate) contributed significantly to ordinations of floral diversity, linking dietary quality with forage composition. DNA sequencing of the ITS2 region of the nuclear ribosomal DNA gene identified pollen from 89 distinct plant genera, with each bee bread sample containing between 6 and 35 pollen types. Dominant genera included dandelion (Taraxacum), which was positively correlated with bee bread protein content, and cherry (Prunus), which was negatively correlated with the amount of protein. In addition, proportions of amino acids (e.g. histidine and valine) varied as a function of floral species composition. These results also quantify the effects of individual plant genera on the nutrition of honey bees. We conclude that pollens of different plants act synergistically to influence host nutrition; the pollen diversity of bee bread is linked to its nutrient content. Diverse environments compensate for the loss of individual forage plants, and diversity loss may, therefore, destabilize consumer communities due to restricted access to alternative resources

Analysis of phototactic responses in Spodoptera frugiperda using Helicoverpa armigera as control

Light traps are widely utilized to monitor and manage insect pest populations. In late 2018, the fall armyworm (FAW), Spodoptera frugiperda, invaded China through Yunnan Province representing a huge threat to grain production. To estimate the efficiency of light traps on FAW moths, we first identified the opsin genes from FAW by using the transcriptome. Phylogenetic analysis indicated that the four opsins of FAW were clustered with those of other Noctuidae species. The expressed levels of opsins in S. frugiperda were lower than in Helicoverpa armigera, suggesting a different phototactic response between the two species. Then, we determined the phototactic behavior of FAW using H. armigera as a control, which is widely monitored and managed using light traps in China. Our results indicated that the two moths species showed significantly different phototactic behavior and both female and male FAW displayed faster flight-to-light speed than H. armigera. This may be due to a faster flight capacity in FAW compared to H. armigera. However, the capture rate of both female and male of S. frugiperda was significantly lower than that of H. armigera, which was consistent with the expression levels of opsins. These results support the positive phototaxis of S. frugiperda moths and suggest light traps could be used for monitoring and managing the pests, but with a lower efficiency than H. armigera. © 2021 CAAS. Publishing services by Elsevier B.

The role of STAT3/p53 and PI3K-Akt-mTOR signaling pathway on DEHP-induced reproductive toxicity in pubertal male rat

Di (2-ethylhexyl) phthalate (DEHP) is a known environmental endocrine disruptor that impairs development of testis and spermatogenesis. This study aims to explore the effects of STAT3/p53 and PI3K-Akt-mTOR signaling pathway on DEHP-induced reproductive toxicity in pubertal male rat. 24 6-week-old male Sprague-Dawley rats were randomly divided into 4 groups (Control, low-dose, middle-dose and high-dose group) and were treated with increasing concentration of DEHP (0, 250, 500, 1000 mg/kg/day) respectively for 28 consecutive days by intragastric administration. Our results showed that DEHP exposure induced obvious morphological changes of testis, decreased organ coefficient of testis and sperm count, and increased testicular cell apoptosis in the 500 and 1000 mg/kg/day DEHP groups