Thermal Stress-Induced Metabolic Shifts in the Parthenium Beetle: An Untargeted Metabolomics Study.

Male traits are expected to evolve on the basis that they help maximize reproductive success. Prolonged copula duration is a commonly observed trait and this may sometimes be an adaptive male tactic that results in increased paternity against rival males. This study evaluated direct and indirect influences of prolonged copula duration on reproduction and offspring development in the parthenium beetle, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae). Prolonged copula duration was correlated with a reduction in the time until oviposition and with increased fecundity in female beetles. Furthermore, extended copula duration was correlated with increased offspring survival and reduced offspring development times. Thus, there appear to be both direct and indirect benefits associated with prolonged copula in the parthenium beetle (i.e., increased adult reproductive performance and improved offspring fitness). Possible explanations for these reproductive benefits may be that a longer copula increases the availability of sperm for females and seminal fluid may boost maternal protein reserves which can then be invested in higher quality of offspring.

Slow and fast development in Parthenium beetle and its effect on reproductive attributes

Insects experience variable temperature conditions in their natural environment, making constant temperature conditions in studies unrealistic. To address this, we investigated the effects of repeated short-term heat stress (STH) and short-term cold stress (STC) conditions on the pre-oviposition, oviposition, and post-oviposition periods, as well as on fecundity and egg viability of the parthenium beetle, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae). We found that pre-oviposition periods were shortest under STH conditions and at the optimal temperature and longest under STC conditions. Conversely, oviposition and post-oviposition periods were longest at the optimal temperature. Oviposition periods were shortest under STH, whereas post-oviposition periods were shortest under both STH and STC conditions. Age-specific fecundity trends were triangular, and egg-viability trends were plateau-shaped at all temperatures. Females subjected to STH conditions experienced the highest oviposition peaks early in their adult life. Conversely, lifetime fecundity and longevity were highest at the optimal temperature, whereas egg viability was maximal under STH conditions. Regardless of the temperature they were maintained at, middle-aged females exhibited the highest fecundity and egg viability. Based on these results, despite reducing overall fecundity and longevity, STH conditions enhanced daily oviposition in females, with the peak occurring early in adult life. Additionally, both STH and STC conditions increased percentage egg viability in parthenium beetles.

Size-based intraspecific variations along altitudinal gradient and follow of Bergmann’s rule in Parthenium beetle, Zygogramma bicolorata Pallister

Insects encounter variable temperature conditions in their natural habitats. Under non‐optimal temperatures, they experience thermal stress and oxidative damage, which are mitigated by antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT) and lipid peroxidation (LPO). While short‐term effects of thermal stress on antioxidant enzyme activities in insects are well understood, the long‐term effects are less explored. We investigated both short‐term (3 and 6 h) and long‐term (24 h) effects of thermal stress on SOD, CAT and LPO activities in the Parthenium beetle, Zygogramma bicolorata Pallister at cold (15°C), control/optimal (25°C) and hot (35°C) temperatures. Although Z. bicolorata is an effective biocontrol agent for noxious Parthenium weed, no prior study assessed the impact of thermal stress on antioxidant enzyme activities in this beetle. Our results revealed that antioxidant enzymes activities increased above control levels in both larvae and adults when exposed to thermal stress for short durations. Under long‐term thermal stress, CAT and LPO activities decreased below control levels, while SOD activity increased. Regardless of temperature conditions, early larval instars exhibited higher enzyme activities compared to later instars. In adults, males showed higher SOD and CAT activities, whereas LPO activity did not differ significantly between sexes. Our findings suggest that short‐term thermal stress can stimulate protective enzyme activity in these beetles and help them adapt to suboptimal temperatures. However, prolonged exposure may lead to excessive stimulation, potentially inhibiting protective enzyme activity and causing the beetles to activate alternative pathways to manage thermal stress. Moreover, fourth instars and adult females are the most thermal stress‐tolerant stages for Parthenium biocontrol.

Short-chain chlorinated paraffins (SCCPs) are an emerging class of persistent organic pollutants (POPs) that are widely detected in environmental matrices and human samples. Because of their environmental persistence, long-range transport potential, bioaccumulation potential, and biotoxicity, SCCPs pose a significant threat to human health. In this study, metabolomics technology was applied to reveal the metabolomic interference in human normal hepatic (L02) cells after exposure to low (1 μg/L), moderate (10 μg/L), and high (100 μg/L) doses of SCCPs. Principal component analysis (PCA) and metabolic effect level index (MELI) values showed that all three SCCP doses caused notable metabolic perturbations in L02 cells. A total of 72 metabolites that were annotated by MS/MS and matched with the experimental spectra in the Human Metabolome Database (HMDB) or validated by commercially available standards were selected as differential metabolites (DMs) across all groups. The low-dose exposure group shared 33 and 36 DMs with the moderate- and high-dose exposure groups, respectively. The moderate-dose exposure group shared 46 DMs with the high-dose exposure group. In addition, 33 DMs were shared among the three exposure groups. Among the 72 DMs, 9, 9, and 45 metabolites participated in the amino acid, nucleotide, and lipid metabolism pathways, respectively. The results of pathway enrichment analysis showed that the most relevant metabolic pathways affected by SCCPs were the lipid metabolism, fatty acid β-oxidation, and nucleotide metabolism pathways, and that compared with low-dose exposure, moderate- and high-dose SCCP exposures caused more notable perturbations of these metabolic pathways in L02 cells. Exposure to SCCPs perturbed glycerophospholipid and sphingolipid metabolism. Significant alterations in the levels of phosphatidylcholines, phosphatidylethanolamines, and sphingomyelins indicated SCCP-induced biomembrane damage. SCCPs inhibited fatty acid β-oxidation by decreasing the levels of short- and medium-chain acylcarnitines in L02 cells, indicating that the energy supplied by fatty acid oxidation was reduced in these cells. Furthermore, compared with low- and moderate-dose SCCPs, high-dose SCCPs produced a significantly stronger inhibition of fatty acid β-oxidation. In addition, SCCPs perturbed nucleotide metabolism. The higher hypoxanthine levels observed in L02 cells after SCCP exposures indicate that SCCPs may induce several adverse effects, including hypoxia, reactive oxygen species production, and mutagenesis in L02 cells.

Coconut is an important tropical and subtropical fruit and oil crop severely affected by cold temperature, limiting its distribution and application. Thus, studying its low-temperature reaction mechanism is required to expand its cultivation range. We used growth morphology and physiological analyses to characterize the response of coconuts to 10, 20, and 30 d of low temperatures, combined with transcriptome and metabolome analysis. Low-temperature treatment significantly reduced the plant height and dry weight of coconut seedlings. The contents of soil and plant analyzer development (SPAD), soluble sugar (SS), soluble protein (SP), proline (Pro), and malondialdehyde (MDA) in leaves were significantly increased, along with the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and the endogenous hormones abscisic acid (ABA), auxin (IAA), zeatin (ZR), and gibberellin (GA) contents. A large number of differentially expressed genes (DEGs) (9968) were detected under low-temperature conditions. Most DEGs were involved in mitogen-activated protein kinase (MAPK) signaling pathway-plant, plant hormone signal transduction, plant–pathogen interaction, biosynthesis of amino acids, amino sugar and nucleotide sugar metabolism, carbon metabolism, starch and sucrose metabolism, purine metabolism, and phenylpropanoid biosynthesis pathways. Transcription factors (TFs), including WRKY, AP2/ERF, HSF, bZIP, MYB, and bHLH families, were induced to significantly differentially express under cold stress. In addition, most genes associated with major cold-tolerance pathways, such as the ICE-CBF-COR, MAPK signaling, and endogenous hormones and their signaling pathways, were significantly up-regulated. Under low temperatures, a total of 205 differentially accumulated metabolites (DAMs) were enriched; 206 DAMs were in positive-ion mode and 97 in negative-ion mode, mainly including phenylpropanoids and polyketides, lipids and lipid-like molecules, benzenoids, organoheterocyclic compounds, organic oxygen compounds, organic acids and derivatives, nucleosides, nucleotides, and analogues. Comprehensive metabolome and transcriptome analysis revealed that the related genes and metabolites were mainly enriched in amino acid, flavonoid, carbohydrate, lipid, and nucleotide metabolism pathways under cold stress. Together, the results of this study provide important insights into the response of coconuts to cold stress, which will reveal the underlying molecular mechanisms and help in coconut screening and breeding.

Investigations of age‐based food conversion and utilization efficiencies in phytophagous insects are very few. Studies examining the effects of age, sex and mating status on biochemical assimilation of macronutrients by phytophagous insects are scarce as well. Hence, we designed the present study to evaluate the combined effect of age, sex and mating status on food consumption and utilization efficiencies, and the assimilation of macronutrients by the Parthenium beetle, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae), on the invasive weed, Parthenium hysterophorus Linnaeus (Asterales: Asteraceae). We hypothesized that mated adults would consume and utilize more food than unmated adults, that assimilation of nutrients by old adults would be lower than young adults and that females would consume and utilize food more efficiently than males. However, our results revealed that as adults aged, their food consumption and utilization efficiencies decreased, and they assimilated less proteins and glucose in their body. Despite that, their mean body biomass and assimilation of triglycerides increased. While mated adults had higher food utilization efficiencies and increased assimilation of triglycerides and glucose, unmated adults assimilated more proteins. Females had higher food consumption rates and increased assimilation of nutrients, whereas males had higher food conversion efficiencies and growth rates. Furthermore, middle‐aged adults had higher food utilization efficiencies and they assimilated more nutrients than young and old adults. Our results therefore suggest compensatory feeding in adults of Z. bicolorata with ageing. We also recommend the release of more numbers of mated middle‐aged females to control P. hysterophorus in agro‐ecosystems.

In the Parthenium beetle, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae), variation in body size exists between and within the sexes. The females are larger than the males. Darwin (1874) proposed the fecundity advantage hypothesis, i.e. large sized female produce more progeny, with subsequent studies supporting as well as refuting the hypothesis. Thus, in order to evaluate whether this hypothesis stands in Z. bicolorata we performed experiments to investigate the role of body size in influencing: (i) assortative mating, (ii) reproductive attributes, and (iii) growth, development and survival of offspring. It is the first attempt in this beetle. We found that size influenced assortative mating, reproductive output and offspring fitness. Larger males and females were preferred as mates over smaller ones. The pairs having larger adults as mates had higher fecundity while the egg viability was influenced by the male size only. The offspring of larger parents had fast development and higher survival indicating thereby possible better nutrient allotment by the female and supply of accessory gland proteins by the male in addition to better quality of genes.

The Parthenium beetle, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae) is a notable biocontrol agent against invasive Parthenium weed in Australia, South Africa, and the Indian subcontinent. While larvae consume both inflorescences and leaves, and adults feed exclusively on leaves, no prior study has compared the mouthparts of Z. bicolorata larvae and adults. Present study utilized scanning electron microscopy to investigate the morphology and distribution of sensilla on mouthparts of fourth-instar larvae, pupae, and adults. Our results revealed that fourth-instar larvae had 9-different sensillum types: sensilla chaetica (Sch I-III), sensilla basiconica (Sb I-V), and sensilla digitiformia (Ds) on their mouthparts, whereas pupal sensilla were fewer and less distinct. In adults, 13-different sensillum types were present: sensilla chaetica (Sch I-III) on labrum, labium, mandibles, and maxillae; sensilla basiconica (Sb I-VI) on labium, epipharyx, lacinia, maxillary palps, and labial palps; sensilla digitiformia (Ds) on maxillary palps; and sensilla campaniformia (Sca), and sensilla coeloconica (Sco I-II) on epipharyx. These sensilla likely play vital roles in feeding behavior, sensory perception, and host plant detection. Our findings provide a microscopic morphological foundation for further research on food recognition mechanisms and local adaptations in specialist phytophagous insects.

Purpose: Parthenium hysterophorus L. is a globally recognized one of the most invasive noxious weeds. It has invaded more than 17 districts in Sri Lanka, and is listed under weed of national significance for eradication. Biological control using parthenium beetle Zygogramma bicolorata is one of the promising eco-friendly strategies for Parthenium management and is successful in many countries.Research Method: The biennial survey was conducted to explore the potential biocontrol agent Z. bicolarata of the parthenium and its dispersal around Northern Sri Lanka. Preliminary survey data identified sampling sites that were chosen to draw the distribution and density maps of Parthenium beetle (Z. bicolarata) using GPS tools. The field and greenhouse damage incidence of Z. bicolarata on Parthenium was calculated and subjected to ANOVA using SAS 9.1. Tukey's HSD multiple comparison test to identify the best treatment combination at P <0.05.Findings: The results exhibit that the Z. bicolarata distribution is confined to the Jaffna district in Northern Sri Lanka, and occurrence was first time in Valikamam North in the year 2019/20. The highest density of the Z. bicolorata population was 35-62 per m2 in the Valikamam North DS division in the years 2019/20 and 2020/21, respectively. The damage incidence varied from <10%-100%, but maximum field damage was 25->50% in Valikamam North whereas in the greenhouse 10 grubs inflicted 75-100% defoliation in 9±0.75 days.Originality/Value: This is the first report of occurrence of Z. bicolorata and detailed study of its distribution, damage on Parthenium to decide the biological Parthenium control programme.

Transcriptomic and metabolomic investigations of methyl jasmonate-mediated enhancement of low temperature stress resistance in Cassia obtusifolia L.

Parthenium hysterophorus L. (Asteraceae) is a noxious weed found in agricultural fields, pastures, and wastelands across tropical regions. It significantly reduces crop yields and poses serious health risks to humans. The Mexican beetle, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae), has emerged as one of the most effective biological control agents against this weed. However, no previous research has examined the beetle's nutrient assimilation. This study evaluated the feeding behavior and nutrient assimilation in the larvae of Z. bicolorata when feeding on P. hysterophorus. The findings showed that the first instar larvae had the lowest food consumption rates and accumulated minimal amounts of glucose, proteins in their bodies. These larvae demonstrated compensatory feeding behavior, achieving the highest food utilization efficiency and developmental rates. In contrast, the fourth instar larvae exhibited the highest food consumption and conversion efficiency but had the slowest developmental rates. Notably, the fourth instar larvae accumulated the largest food reserves. These results provide valuable insights for laboratory-based mass-rearing programs for Z. bicolorata, though further field trials are necessary to validate these findings.

Global warming is predicted to increase prolonged thermal challenges for aquatic ectotherms, i.e. it causes metabolic performance declines, impacts food intake, and finally causes impaired growth. In this research work, we investigated whether a tropical fish, Danio rerio (zebrafish), could tolerate prolonged thermal challenges and whether the temperature increase has a significant impact on growth and metabolism. To answer our questions, we evaluate the metabolomic performance, a question that has received little attention so far, using differential chemical isotope labeling (CIL) liquid chromatography-mass spectrometry (LC-MS). Three groups of fish were exposed to various temperatures of 27.6 ± 2°C, 30.7 ± 2°C or 32.2 ± 2°C during 270 days post fecundation (dpf) to evaluate the impact of the temperature increase on the growth and metabolomic performance. The results obtained demonstrated different metabolomic changes in response to acclimation to the different temperatures. After 270 days, the fish maintained at the highest tested temperature (32°C) showed reduced growth, reduced condition factor, and elevated levels of metabolites associated with amino acid catabolism and lipid metabolism pathways in the liver and intestine compared with fish kept at lower temperatures (27.6 ± 2°C). These findings demonstrate an explicit redistribution of energy stores and protein catabolism in fish at the highest temperature, thus showing a preference for maintaining length growth during limited energy availability. Moreover, here we also screened out both the marker metabolites and the altered metabolic pathways to provide essential insights to ascertain the effects of the water temperature increase on the growth and development of tropical fish.

True morels (Morchella, Pezizales) are a popular edible and medicinal fungus with great nutritional and economic value. The dynamics and regulatory mechanisms during the morphogenesis and maturation of morels are poorly understood. In this study, the metabolomes and transcriptomes of the mycelium (MY), primordium differentiation (PR), young fruiting body (YFB), and mature fruiting body (MFB) were comprehensively analyzed to reveal the mechanism of the morphogenesis and maturation of Morchella sextelata. A total of 748 differentially expressed metabolites (DEMs) and 5342 differentially expressed genes (DEGs) were detected, mainly enriched in the carbohydrate, amino acid, and lipid metabolism pathways, with the transition from the mycelium to the primordium being the most drastic stage at both the metabolic and transcriptional levels. The integrated metabolomics and transcriptomics highlighted significant correlations between the DEMs and DEGs, and specific amino acid and nucleotide metabolic pathways were significantly co-enriched, which may play key roles in morphological development and ascocarp maturation. A conceptual model of transcriptional and metabolic regulation was proposed during morphogenesis and maturation in M. sextelata for the first time, in which environmental factors activate the regulation of transcription factors, which then promote metabolic and transcriptional regulation from vegetative to reproductive growth. These results provide insights into the metabolic dynamics and transcriptional regulation during the morphogenesis and maturation of morels and valuable resources for future breeding enhancement and sustainable artificial cultivation.