The velvetbean caterpillar, Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae), is an important soybean pest in the Americas. Tebufenozide, a novel nonsteroidal ecdysone agonist is used to control ...this pest. Bioassays were conducted to assess tebufenozide toxicity and their ultrastructural effects on midgut of A. gemmatalis. The toxicity, survivorship, behavior response, and respiration rate for A. gemmatalis larvae after exposure to tebufenozide were evaluated. Also, A. gemmatalis larvae were treated with LC50 obtained from tebufenozide and changes were observed on their midgut cells after 24, 48 and 96 h. Tebufenozide was toxic to A. gemmatalis (LC50 = 3.86 mg mL−1 and LC90 = 12.16 mg mL−1) and survivorship was 95% for adults that had not been exposed to tebufenozide, decreasing to 52% with LC50 and 27% with LC90 estimated value. Damage to midgut cells was increased with exposure time. These cells show damaged striated border with release of protrusions to the midgut lumen, damaged nuclear membrane and nucleus with condensed chromatin and increase in amount of autophagic vacuoles. Mitochondria were modified into nanotunnels which might be an evidence that tebufenozide induces damage to cells, resulting in cell death, proved by immunofluorescence analyses. This insecticide also caused paralysis movement with change in homeostasis and compromised larval respiration. Thus, sublethal exposure to tebufenozide is sufficient to disturb the ultrastructure of A. gemmatalis midgut, which might compromise insect fitness, confirming tebufenozide a possible controlling insecticide.
•The insecticidal effect of Tebufenozide was tested against A. gemmatalis.•A. gemmatalis showed significant changes in histology and ultrastructure.•Induction of mitochondrial nanotunnels by Tebufenozide.•Tebufenozide compromises respiration and behavior of A. gemmatalis.
Lepidopteran pests such as fall armyworm, Spodoptera frugiperda (JE Smith), and black cutworm, Agrotis ipsilon Hufnagel (both Noctuidae), are serious problems of turfgrass (Poaceae) in the USA. ...Several predators in turfgrass systems attack lepidopteran larvae; however, their predaceous activity is rarely recorded, as they leave hardly any evidence. Predaceous activity can be studied using clay models, an approach still rarely employed in turfgrass. Thus, assays were conducted to determine the types of impressions that common turfgrass arthropods leave on clay models simulating lepidopteran larvae. Nine impression types were characterized after exposing 16 arthropod taxa in enclosed arenas in the laboratory and one taxon in the field to two sizes of clay models, including scratches, paired marks, pricks, deep distortions, disturbed surfaces, detached segments, granulated surfaces, dents, and elongated scratches. Most arthropods produced scratches and paired marks, whereas granulated surfaces and elongated scratches were produced by only a few of the selected arthropods. To ensure that the impressions were correctly identified, non‐expert volunteers reviewed the impressions, and they were accurately identified in >85% of the responses. Video recordings of arthropod interactions were captured to determine the behavior of the arthropods during their first interaction with the clay models. Most arthropods first interacted with the terminal rather than the middle regions of the models. There were no differences between their interactions with the large or small models, and they used their mouthparts as often as their legs. Knowledge of the impression types caused by common arthropods will improve the utilization of the clay model technique for field studies in turfgrass. This could contribute to improved management of natural enemies as part of an integrated pest management approach.
Predaceous activity of arthropods against lepidopteran pests can be studied using clay models. We aimed to adapt this method for use in turfgrass systems. Exposure of turfgrass arthropods to clay models of caterpillars produced nine impression types or marks. Video recordings revealed which arthropods interacted with the terminal vs. the middle part of the models, with small or large models, and with mouthparts or legs. These findings will improve field studies in turfgrass and could contribute to improved pest management.
A model of a caterpillar drive is formulated, by means of RecurDyn software. The interaction of the caterpillar track and the roller is analytically described. The influence of the caterpillar track ...on the vehicle’s vertical dynamics is simulated.
In this paper, we prepare a novel biomimetic caterpillar-like alumina fiber with the characteristic of continuous alumina backbone and fine needle whiskers spine. Then the high-performance ...caterpillar-like alumina fiber composite proton exchange membrane (CAPEM) is obtained by introducing the amino modified biomimetic caterpillar-like alumina fiber into sulfonated polysulfone (SPSF) matrix, which successfully reasonable construction of the proton conducting channels in both vertical and horizontal orientation. The properties of CAPEM, including proton conductivity, methanol permeability, etc. Are systematically studied. The results show that the proton conductivity of CAPEM increases with rising the temperature, which reaches the maximum of 0.263 S/cm at 80 °C and 100% RH, respectively. The excellent proton conductivity of CAPEM is attributed to the long-range continuous proton conducting channel formed by the horizontal continuous alumina skeleton in the in-plane direction and the vertical overlapped fine needle whiskers spine in the through-plane direction. In addition, the interfacial compatibility between amino modified caterpillar-like alumina fiber and SPSF matrix is enhanced through the reasonable construction of proton conducting channels, which effectively inhibits the methanol permeation of the composite membrane with 4.18 × 10−7 cm2 s−1 and improves the comprehensive performance of the CAPEM.
•A novel biomimetic caterpillar-like alumina fiber is successfully prepared.•The proton conducting channels of CAPEM are reasonable constructed.•Proton conductivity of CAPEM is highly of 0.263 S/cm at 80 °C and 100% RH.•The inhibited methanol permeation of the CAPEM is 4.18 × 10−7 cm2 s−1.
Herbivore‐induced plant volatiles (HIPVs) are important cues for female parasitic wasps to find hosts. Here, we investigated the possibility that HIPVs may also serve parasitoids as cues to locate ...mates. To test this, the odour preferences of four braconid wasps – the gregarious parasitoid Cotesia glomerata (L.) and the solitary parasitoids Cotesia marginiventris (Cresson), Microplitis rufiventris Kokujev and Microplitis mediator (Haliday) – were studied in olfactometers. Each species showed attraction to pheromones but in somewhat different ways. Males of the two Cotesia species were attracted to virgin females, whereas females of M. rufiventris were attracted to virgin males. Male and female M. mediator exhibited attraction to both sexes. Importantly, female and male wasps of all four species were strongly attracted by HIPVs, independent of mating status. In most cases, male wasps were also attracted to intact plants. The wasps preferred the combination of HIPVs and pheromones over plant odours alone, except M. mediator, which appears to mainly use HIPVs for mate location. We discuss the ecological contexts in which the combined use of pheromones and HIPVs by parasitoids can be expected. To our knowledge, this is the first study to show that braconid parasitoids use HIPVs and pheromones in combination to locate mates.
We demonstrate that parasitic wasps use herbivore‐induced plant volatiles (HIPVs) in combination with sex pheromones to locate mates, and foraging for hosts and mates are both orientated by HIPVs in parasitoids. To our knowledge, no other study has specifically addressed the use of HIPVs in mate location of parasitoids, and the inclusion of four species of wasps allows us not only to draw several general conclusions but also to call attention to the differences among species in terms of mate‐searching strategies.
Hierarchical ZSM-5 with a caterpillar-shaped morphology is hydrothermally synthesized, and characterized by XRD, SEM, TEM, N
2
adsorption-desorption, and NH
3
-TPD. The synthesis parameters influence ...on the formation of the caterpillar-shaped hierarchical ZSM-5 are investigated and discussed in details. The results suggest that nano-sized ZSM-5 zeolite crystals is yielded from an appropriate precursor and then forms the caterpillar-shaped hierarchical ZSM-5 by in-situ self-assembly of the primary nanocrystals. SEM and TEM images display that the primary crystals in the caterpillar-shaped zeolite samples formed by self-assembly along
b
-axis of MFI zeolite have a size of about 100 nm. Catalytic cracking of triisopropylbenzene (TIPB) is selected as a probe reaction so as to investigate the catalytic performances of the as-synthesized caterpillar-shaped hierarchical ZSM-5 zeolite. The results show that the as-synthesized hierarchical ZSM-5 zeolite with the increased external surfaces exhibits an elevated catalytic activity during the catalytic cracking of TIPB, and the corresponding traditional ZSM-5 zeolite displays very little activity because of the small external surfaces. The results also show that for the hierarchical ZSM-5-40-5.32-2.1, due to the high external surfaces and the interpenetrated hierarchical pore system, a multi-stage cracking process for the reaction TIPB molecule is detected. That may offer a potential highly effective catalyst for the catalytic cracking of bulky reactant molecule.
Monarch butterflies,
Danaus plexippus,
migrate long distances over which they encounter host plants that vary broadly in toxic cardenolides. Remarkably little is understood about the mechanisms of ...sequestration in Lepidoptera that lay eggs on host plants ranging in such toxins. Using closely-related milkweed host plants that differ more than ten-fold in cardenolide concentrations, we mechanistically address the intake, sequestration, and excretion of cardenolides by monarchs. We show that on high cardenolide plant species, adult butterflies saturate in cardenolides, resulting in lower concentrations than in leaves, while on low cardenolide plants, butterflies concentrate toxins. Butterflies appear to focus their sequestration on particular compounds, as the diversity of cardenolides is highest in plant leaves, lower in frass, and least in adult butterflies. Among the variety of cardenolides produced by the plant, sequestered compounds may be less toxic to the butterflies themselves, as they are more polar on average than those in leaves. In accordance with this, results from an
in vitro
assay based on inhibition of Na
+
/K
+
ATPase (the physiological target of cardenolides) showed that on two milkweed species, including the high cardenolide
A. perennis
, extracts from butterflies have lower inhibitory effects than leaves when standardized by cardenolide concentration, indicating selective sequestration of less toxic compounds from these host plants. To understand how ontogeny shapes sequestration, we examined cardenolide concentrations in caterpillar body tissues and hemolymph over the course of development. Caterpillars sequestered higher concentrations of cardenolides as early instars than as late instars, but within the fifth instar, concentration increased with body mass. Although it appears that large amounts of sequestration occurs in early instars, a host switching experiment revealed that caterpillars can compensate for feeding on low cardenolide host plants with substantial sequestration in the fifth instar. We highlight commonalities and striking differences in the mechanisms of sequestration depending on host plant chemistry and developmental stage, which have important implications for monarch defense.
Given a graph G=(V,E), let L(G) denote its line graph and M(G) denote the number of perfect matchings of G. In this paper, for a traceable graph G of order n with a Hamilton path Pn, we first observe ...that M(L(G)) can be expressed as M(L(G))=∑T∈TM(L(T)), where T is the set of caterpillar trees determined by G and Pn. Then by determining the minimum and maximum values of M(L(T)),T∈T, we obtain lower and upper bounds for M(L(G)). We also show that our lower bounds for this kind of graphs are much better than some known lower bounds for general graphs if the average degree of G is larger than 4.
Background and Objectives: Cholesterol hyper-accumulation is a growing factor causing cardiovascular diseases (CVD), a leading cause of global mortality and accounts for 16.7 million deaths ...worldwide. As far as India is concerned, there is an increase from 25.7 to 54.7 million cases of CVD per year since the year 1990, and change in the dietary pattern being the major cause of this condition. Amongst, coronary heart disease and atherosclerosis remain prominent with its major causative agent as high cholesterol levels. However, the current treatment of these diseases is inadequate, and impose systemic toxicity such as stent thrombosis, chronic inflammation, etc., probiotics with cholesterol-lowering ability is an ideal and safe choice for the prevention of the condition. Materials and Methods: The present study involved the culture-dependent method for the enumeration of microorganisms from caterpillar frass. Upon microscopic screening, yeast isolates were further characterized for their in-vitro probiotic potential such as toxicity assessment, tolerance to pH, bile, temperature, and salt conditions, safety assessment by measuring antibiotics susceptibility, evaluating antagonistic activity, assessing survival in simulated gastrointestinal environment, measuring aggregation capability, evaluating cholesterol-lowering activity and identifying microorganisms using molecular identification tools. Results and Conclusion: The culture-dependent approach resulted in the isolation of four yeast cultures from the frass of Pyrrharctia isabella caterpillar. Yeast cultures designated as CP-I, CP-II, CP-III, and CP-IV were resistant for bile (1.2%), wide range of pH (1.5–10), and up to 42ºC temperature along with antimicrobial activity. CP-I culture also possessed bile salt hydrolase while tolerated stressful salt conditions, gastrointestinal environment, and exhibited good aggregation properties and hydrophobicity. Interestingly, CP-I could reduce cholesterol levels by 9.16% under in-vitro conditions. Molecular identification of CP-I showed its genetic similarity 97% with Saccharomyces cerevisiae. This study demonstrated for the first-time isolation of cholesterol-lowering probiotic yeast Saccharomyces cerevisiae from caterpillar frass in in-vitro conditions.
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