Browsing by Author "Arvind Kumar Patel"

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Ageing and mating status affect food utilization efficiencies and assimilation of macronutrients in adults of Parthenium beetle, Zygogramma bicolorata Pallister
(John Wiley and Sons Inc, 2024) Priyanka Yadav; Priya Patel; Arvind Kumar Patel; Ritabrata Chowdhury; Ankit Upadhyay; Bhupendra Kumar; Dinesh Kumar
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. © 2024 Royal Entomological Society.
Functional complexity of Parthenium beetle, Zygogramma bicolorata (Pallister) under thermal-stress conditions: Insights from Gene Ontology
(Elsevier B.V., 2025) Arvind Kumar Patel; Bhupendra Kumar
We analyzed protein expression profiles in Parthenium beetles exposed to cold (15 °C), optimal (25 °C), and heat (35 °C) temperatures. The beetle is an effective biocontrol agent against the invasive Parthenium weed. We identified 620 proteins under cold stress, 334 proteins at the optimal temperature, and 603 proteins under heat stress, with 181 proteins common to all three temperature conditions. Compared to the 106 proteins expressed at the optimal temperature, 196 proteins were overexpressed under cold stress, while 180 proteins were overexpressed under heat stress. Under cold stress, significant Gene Ontology (GO) terms for molecular functions included pyridoxal phosphate binding, pyrophosphatase activity, and RNA helicase activity. Enriched cellular component terms were trans-Golgi network transport vesicle, endosome, and small ribosomal subunit. Biological processes emphasized small molecule biosynthesis, protein refolding, and carbohydrate metabolism. Under heat stress, significant GO terms for molecular functions involved proton transmembrane transporter activity, poly-A binding, and oxidoreductase activity. Cellular component terms included cytosol, coated vesicle, and nucleosome. Biological processes highlighted regulation of cellular stress response, primary active transmembrane transport, and heterochromatin formation. These findings reveal distinct protein sets and associated functions under thermal stress, providing insights into the beetle's molecular mechanisms of thermal adaptation. The enriched GO terms indicate activation of different molecular pathways in response to cold and heat stress, involving various metabolic, transport, and stress response processes. © 2025 Korean Society of Applied Entomology
Impact of short- and long-duration thermal stress on antioxidant enzyme activity in Parthenium beetles
(John Wiley and Sons Inc, 2025) Priyanka Yadav; Arvind Kumar Patel; Parinita Singh; Sourabh Verma; Ritabrata Chowdhury; Bhupendra Kumar
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. © 2024 Royal Entomological Society.
Impact of short- and long-duration thermal stress on antioxidant enzyme activity in Parthenium beetles
(John Wiley and Sons Inc, 2024) Priyanka Yadav; Arvind Kumar Patel; Parinita Singh; Sourabh Verma; Ritabrata Chowdhury; Bhupendra Kumar
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. © 2024 Royal Entomological Society.
Morphology of Mouthparts and Distribution of Sensilla in Immature Stages and Adults of Parthenium Beetles
(Oxford University Press, 2025) Priyanka Yadav; Arvind Kumar Patel; Desh Deepak Chaudhary; Bhupendra Kumar
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. © The Author(s) 2025. Published by Oxford University Press on behalf of the Microscopy Society of America. All rights reserved.
Morphometric analysis of Parthenium beetle, Zygogramma bicolorata (Pallister) under thermal-stress conditions
(Springer Nature, 2025) Arvind Kumar Patel; Priyanka Yadav; Bhupendra Kumar
This study highlights the effects of thermal stress on the morphology of the Parthenium beetle, Zygogramma bicolorata Pallister. Our findings indicate that temperature significantly influences the body biomass of adults, with optimal (25 ± 2 °C) conditions resulting in the highest biomass. Body size and antennal length were reduced under both cold (15 ± 2 °C) and hot (35 ± 2 °C) conditions, with greater variability recorded at cold temperatures. Moreover, cold stress increased melanization and induced developmental abnormalities, such as fused flagellomeres in the antennae. The abundance of sensilla varied significantly across temperature treatments, except for sensilla chaetica types I and II. Antennal segments also exhibited temperature-dependent variations in length. Eight types of sensilla were identified, with sensilla trichodea I and sensilla coeloconica being more abundant under thermal extremes, potentially influencing host and mate detection. Sensilla chaetica were the most widespread and robust, displaying variability in both length and abundance. Structural differences were observed between sensilla trichodea and sensilla basiconica, particularly in terms of curvature and socket embedding. Overall, the results suggest that thermal stress affects both morphological and sensory traits in Z. bicolorata, which may in turn, impact their survival and reproductive success. © African Association of Insect Scientists 2025.
Physiological responses of Parthenium beetles, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae), to fluctuating temperature stress
(Cambridge University Press, 2025) Arvind Kumar Patel; Priyanka Yadav; Bhupendra Kumar
Phytophagous insects are influenced by various abiotic factors, with temperature being a key determinant. We hypothesised that fluctuating thermal conditions would enhance antioxidant enzyme activity and nutrient assimilation in these insects. We investigated superoxide dismutase, catalase, and lipid peroxidation activity, as well as glucose and triglyceride assimilation in Parthenium beetles, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae), under repeated exposure to short-duration heat (42 ± 2 °C) and cold (10 ± 2 °C), and optimal (27 ± 2 °C) temperatures, along with post-stress recovery. Results revealed that superoxide dismutase, catalase, and lipid peroxidation activity were highest under the heat stress and lowest under the cold stress conditions. Upon returning to optimal conditions, adults previously exposed to thermal stress showed reduced superoxide dismutase and catalase activity and elevated lipid peroxidation product levels compared to those reared continuously at optimal temperatures. Glucose assimilation was highest under cold stress, whereas triglyceride assimilation peaked under optimal temperatures. After stress conditions ended, glucose assimilation decreased in beetles across all temperature groups, whereas triglyceride assimilation increased in adults that had been maintained at optimal temperatures. Adult mortality peaked under heat stress, with male beetles showing higher mortality rates than females did. Moreover, male beetles exhibited higher enzyme activity, whereas female beetles assimilated more glucose and triglycerides, suggesting greater thermal-stress tolerance in the females. These findings imply that female Parthenium beetles are more resilient to thermal stress and are therefore more effective for use in Parthenium (Asteraceae) biocontrol. © The Author(s), 2025.
Repeated short-term thermal stress and its impact on reproductive fitness in parthenium beetle, Zygogramma bicolorata (Coleoptera: Chrysomelidae)
(Cambridge University Press, 2024) Arvind Kumar Patel; Priyanka Yadav; Bhupendra Kumar
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. © The Author(s), 2024.
Semiochemical footprints of the predaceous coccinellid beetle, Menochilus sexmaculatus, deter Zygogramma bicolorata (Coleoptera: Chrysomelidae) from feeding on Parthenium
(Taylor and Francis Ltd., 2019) Arvind Kumar Patel; Vipin Singh; Priya Patel; Bhupendra Kumar; Dinesh Kumar
Present study assessed if semiochemical cues left by an aphidophagous beetle, M. sexmaculatus influenced foraging behaviour of a phytophagous beetle, Z. bicolorata on noxious weed, P. hysterophorus. The lower predation attributes of Z. bicolorata in presence of M. sexmaculatus semiochemical footprints confirms they interfere with weed biological control. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
Stage specific feeding attributes and mobilization of nutrients in Mexican beetle, Zygogramma bicolorata Pallister on Parthenium hysterophorus L.
(Elsevier B.V., 2020) Priya Patel; Shailesh Singh; Arvind Kumar Patel; Bhupendra Kumar; Arvind Kumar Singh; Dinesh Kumar
Parthenium hysterophorus L. (Asteraceae) is a toxic weed of agricultural farms, pastures and wastelands with a pan-tropical distribution. The weed causes a reduction in crop production of agricultural fields and severe health problems in humans. The Mexican beetle, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae) is among the most promising candidates for the weed biocontrol. However, no previous study has evaluated assimilation of nutrients in this beetle. In the present study, feeding attributes and assimilation of nutrients by larvae of Z. bicolorata were assessed on the weed. Results revealed that the first larval instars of Z. bicolorata exhibited lowest consumption rates, and accumulated minimum concentrations of glucose, proteins and triglycerides in their body. They showed compensatory feeding, and displayed highest food utilization efficiencies and developmental rates. In contrast, the fourth larval instars exhibited higher food consumption rates and conversion efficiencies, but displayed lowest developmental rates. Accumulation of food reserves was also recorded maximum for the fourth larval instars. Overall, the findings may aid current mass-rearing efforts for Z. bicolorata in laboratories, but field trials are still needed to strengthen the present findings. © 2020
Temperature modulates feeding attributes, biochemical assimilation of macronutrients and rate of development in larvae of Parthenium beetles
(John Wiley and Sons Inc, 2025) Priya Patel; Arvind Kumar Patel; Priyanka Yadav; Ankit Upadhyay; Bhupendra Kumar; Dinesh Suresh Kumar
The present study assessed the feeding efficiency, macronutrient assimilation and larval development of the Parthenium beetle, Zygogramma bicolorata Pallister, a biocontrol agent for the invasive Parthenium weed, under varying temperature conditions. We hypothesized that deviations from the optimal temperature (~25°C) would impair larval feeding efficiency due to temperature-induced stress. Our results revealed that both larval consumption and growth rates declined at temperatures below (15°C, 20°C) and above (30°C) the optimal temperature (25°C). In contrast, food conversion efficiency improved as temperatures increased from 15 to 30°C. Protein assimilation by larvae decreased across the temperature range, while glucose assimilation increased. Triglyceride assimilation initially decreased from 15 to 20°C/25°C but increased from 20°C/25°C to 30°C. As temperatures increased from 15 to 30°C, both the body size and developmental durations of larvae decreased. These findings suggest that Z. bicolorata larvae adopt different survival strategies depending on temperature conditions. At suboptimal temperatures, larvae grow larger, assimilate more proteins and triglycerides, but consume and utilize food more slowly. Conversely, at supraoptimal temperatures, larvae exhibit reduced body size and food consumption rates, but their food utilization efficiency improves, leading to faster development. Therefore, both low and high temperatures could limit the biocontrol efficiency of Z. bicolorata larvae in the Indian subcontinent. © 2025 Royal Entomological Society.