The pine caterpillar (Dendrolimus spectabilis Bulter, Lepidoptera: Lasiocampidae), as an ectotherm, temperature plays a crucial role in its development. With climate change, earlier development of ...insect pests is expected to pose a more frequent threat to forest communities. Yet the quantitative research about the extent to which global warming affects pine caterpillar populations is rarely understood, particularly across various elevations and latitudes. Spring phenology of pine caterpillars showed an advancing trend with 0.8 d/10a, 2.2 d/10a, 2.2 d/10a, and 3.3 d/10a under the SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5 scenario, respectively. There was a maximum advance of 20 d in spring phenology of pine caterpillars during the 2090s, from mid-March to early March, and even late February. This study highlighted the significant advance in spring phenology at elevations >1000 m and lower latitudes. Consequently, the differences in elevational and latitudinal gradients were relatively small as the increasing temperatures at the end of the 21st century. And the average temperature in February–March was effective in explaining theses variability. These findings are crucial for adapting and mitigating to climate change.
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•Global warming has led to a notable advancement in pine caterpillar spring phenology.•Pine caterpillars are earlier by 0 to 48 %, shifting from mid-March to late February.•Significant shifts in pine caterpillar development at >1000 m elevations, 38–38.5°N.
Let G=(V,E) be a connected graph with m edges. An antimagic labeling of G is a one-to-one mapping from E to {1,2,…,m} such that the vertex sum (i.e., sum of the labels assigned to edges incident to a ...vertex) for distinct vertices are different. A graph G is called antimagic if G has an antimagic labeling. It was conjectured by Hartsfield and Ringel that every tree other than K2 is antimagic. The conjecture remains open though it was verified for trees with some constrains. Caterpillars are an important subclass of trees. This paper shows caterpillars with maximum degree 3 are antimagic, which gives an affirmative answer to an open problem of Lozano et al. (2019).
A water-soluble polysaccharide, named NCSP-50, was obtained from natural Cordyceps sinensis by hot water extraction and ethanol fractionation precipitation. It was eluted as a single symmetrical peak ...and had an average molecular weight of 9.76 × 105 Da. The structure was determined by monosaccharide composition, methylation analysis, 1D/2D NMR spectroscopy, and enzymatic hydrolysis and characterization of the oligosaccharides by MALDI-TOF mass spectrometry. The repeating unit of this polysaccharide was proposed as follows: Display omitted
This glucan showed potent immunostimulatory activity on the basis of its significant abilities to promote macrophage proliferation, enhance NO production, as well as and cytokines (IL-1β and TNF-α) secretion.
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•A homogenous polysaccharide (NCSP-50) from natural Cordyceps sinensis was isolated and purified.•NCSP-50 is a 4-linked α-glucan substituted by α-glucose units attached to C-6.•The glucan showed a significant immunostimulatory effect on macrophages.
The pre-excavation activity of the neonate larvae of
Cactoblastis cactorum
(Lepidoptera: Pyralidae) is typically confined to an arena that encircles the base of their egg stick. If the caterpillars ...are unable to penetrate the host plant within the arena, they strike off en masse in search of a more favorable site, marking their pathway with secretions from their mandibular glands. One component of this secretion, 4-hydroxy-2-oleoylcyclohexane-1,3-dione (an acylcyclohexanedione, ACHD), has been previously shown to function as a trail pheromone. In this paper, we report the characterization, synthesis, and bioassays of a family of 3-acyl fatty acid methyl esters (which we named cactoblastins), a chemically distinct group of mandibular gland compounds that also elicit trail following behavior. The relative effectiveness in eliciting trail following of the ACHD and six, chemically distinct, synthetic cactoblastins was determined. The most bioactive of the cactoblastins was also compared to whole mandibular gland extract to assess its ability to disrupt the aggregative behavior of the neonates and to serve as a biorational alternative to pesticides for managing invasive populations of the caterpillar.
Recent climate change has produced a wide range of shifts in the phenology of species and consequent changes in the relationships among them. However, a dearth of studies exists that evaluates an ...entire trophic pyramid over an extended period. Here I characterize changes in several important variables on such a multitrophic suite of species, which contains two primary producers (sensitive and marsh ferns
Onoclea sensibilis
and
Thelypteris palustris
), one herbivore (caterpillars of the fern moth
Herpetogramma theseusalis
), one primary parasitoid (the braconid wasp
Alabagrus texanus
), and three facultative hyperparasitoids (including the eulophid wasp
Aprostocetus
sp.). I ask how the abundance of these species changes over time, how parasitism and mortality change along with the plants an herbivore selects, how the relationships between the different trophic levels change, and what effect these results play in the makeup of a trophic pyramid. Herbivores prospered most on sensitive fern, while levels of parasitism and mortality on herbivores and primary parasitoids remained relatively similar over the study period. However, facultative hyperparasitoids declined strikingly, and the few remaining individuals increased their exploitation of caterpillars (vs.
Alabagrus
), further decreasing the impact of the fourth trophic level. Since a previous study demonstrated that phenological change by these primary parasitoids exceeds that of their herbivore, further breakdown of the system appears likely.
With climate change projected to increase the frequency and severity of episodic insect outbreak events, assessing potential consequences for soil microbial communities and nutrient dynamics is of ...importance for understanding forest resilience. The forest tent caterpillar (Malacosoma disstria) is an important defoliator of deciduous tree species in temperate and mixed forests of eastern North America with an invasion cycle every 10–12 years and outbreak events that can last 3–6 years. Following a defoliation episode on trembling aspen (Populus tremuloides) from 2015 to 2017 in Abitibi-Témiscamingue, QC, Canada, we sought to test if defoliation resulted in changes to soil bacterial and fungal communities. We hypothesized an increase in soil microbial biomass due to increased caterpillar frass inputs and potential changes in community structure following the event. Soils were sampled in August 2018, May 2019 and July 2019 from sites that had been subjected to defoliation during the outbreak and from sites where no defoliation had been recorded. We assessed soil microbial biomass and fungal to total microbial activity ratio on all sampling dates, and Community Level Physiological Profiles (CLPPs) for 2018 only using a substrate-induced respiration method. Contrary to our hypothesis, we observed a significant 50% decrease in microbial biomass (μg biomass-C g−1 soil hour−1) in defoliated stands, suggesting tree carbon normally allocated towards root exudates was reallocated towards foliage regeneration. We noted a differentiated carbon-based substrate usage following defoliation, but no change in the fungal to total microbial activity ratio. The observed changes in the two years following the defoliation event suggest that defoliation episodes above-ground could trigger changes in soil chemistry below-ground with effects on soil microbial communities that may, in turn, feedback to influence forest plant dynamics.
Abstract
Silicon can increase the natural defence of plants against stresses including herbivorous insects. Silicon dioxide (SiO
2
) is one of the forms of silicon, and despite its wide use in the ...industrial sector, its use in agriculture is still poorly adopted. The aim of this study was to evaluate the effectiveness of foliar application of SiO
2
in inducing defence against
Spodoptera frugiperda
in soybean. The experiments were conducted in a completely randomised design with four treatments (0%, 1%, 2.5%, and 5% of SiO
2
). The effect on cannibalism, biological parameters (mortality, duration of the larval stage, duration of the pupal stage and pupal weight) and wear on the mandible of
S. frugiperda
were evaluated. The foliar silicon content was also determined. The supply of SiO
2
prolonged the duration of the larval and pupal stages of the
S. frugiperda
by 0.56 and 0.17 days for each 1% of SiO
2
applied, respectively. The use of SiO
2
at 5% increased the mortality rate of caterpillars in the larval stage by approximately 25%. There was no effect of SiO
2
application on cannibalism and weight of
S. frugiperda
pupae. There was wear on the caterpillars' jaws in the third and fourth instar at the highest SiO
2
concentration. The application of SiO
2
promoted greater accumulation of silicon in soybean leaves. It is concluded that the foliar application of SiO
2
affects the biological performance of
S. frugiperda
through the induction of defence in the soybean crop and presents itself as a promising strategy in integrated pest management programmes.
This study explores the appropriation and distribution of surplus in caterpillar fungus collection in Qinghai using a diverse economies of surplus approach. Ethnographic fieldwork included ...semi‐structured interviews, focus group discussions, oral histories and participant observations during collection. Findings suggest that one particular enterprise type, with more typically capitalist features has come to dominate caterpillar fungus collection in Qinghai. The surplus appropriation and distribution in this enterprise poses problems for rural farmer collectors in terms of insecure incomes and stringent working conditions that deprive them of their dignity of labour. This study suggests a rethink of surplus appropriation and distribution based on culturally valued dignity of labour to design more sustainable and equitable livelihood within and beyond the dominant model.
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