Artificial Diet Research Articles

Proteomic Analysis of Midgut of Silkworm Reared on Artificial Diet and Mulberry Leaves and Functional Study of Three UGT Genes

There remains a significant gap in production performance and disease resistance between silkworms reared on artificial diets and those reared on mulberry leaves. This study aims to identify key differential proteins through proteomic analysis of the midgut of silkworms fed artificial diets compared to those fed mulberry leaves. Utilizing molecular docking technology, three anti-nutritional factors that consistently bind to the UGT40B4, UGT340C2, and UGT40A1 proteins were selected, and the differential expression of these UGT genes in response to various anti-nutritional factors was examined. The findings indicate that variations in feed significantly influence the expression of digestive, metabolic, and immune-related proteins within the silkworm midgut. Notably, the expression levels of the UGT40B4, UGT340C2, and UGT40A1 genes vary across different silkworm organs and developmental stages, reflecting their respective physiological roles. Furthermore, the effects of soybean isoflavone, tannic acid, and arabinoxylan on silkworm growth and cocoon quality were found to differ when these substances were incorporated into semi-synthetic feed. This research is anticipated to provide valuable insights for future studies on the role of UGT genes in the silkworm midgut and the formulation of artificial diets for silkworms.

A method to screen sugarcane hybrids against Chilo sacchariphagus indicus using artificial diet

A method to screen sugarcane hybrids against Chilo sacchariphagus indicus using artificial diet

Comparative Analyses of Gut Microbiomes in Hycleus cichorii (Coleoptera: Meloidae) Adults Reveal Their Distinct Microbes, Microbial Diversity and Composition Associated to Food.

Gut microbiota crucially affects metabolism and health. Hycleus cichorii Linnaeus has been listed as a medicinal insect in the Pharmacopeia of the People's Republic of China due to the presence of cantharidin, which has a curative effect on many cancers and skin diseases. In order to analyze the effects of dietary habits and gender on the diversity and composition of gut microbiota in H. cichorii and provide a basis for an artificial diet, in this study, the full-length 16S rRNA sequencing technology was used to analyze the gut microbiota of 35 H. cichorii adults, including wild female adults (WFA), wild male adults (WMA), female adults fed with luffa flowers (LFA), male adults fed with luffa flowers (LMA), female adults fed with artificial diet (AFA), and male adults fed with artificial diet (AMA). The results displayed that the major bacterial phyla present in the gut microbiota of the H. cichorii were Firmicutes, Proteobacteria, Bacteroidetes, Fusobacteria, Teneriicutes, and Actinobacteria. The major bacterial genera were Lactococcus, Lactobacillus, Enterococcus, Ralstonia, Sebaldella, Dysgonomonas, Spiroplasma, Weissella, Klebsiella, and Serratia. Food habits had a significant effect on the diversity and composition of gut microbiota in H. cichorii, whereas gender did not exhibit a remarkable impact on the diversity and composition of gut microbiota. The artificially fed group of H. cichorii had more beneficial microorganisms in the intestine and higher food utilization efficiency. These results provide a basis for subsequent examination of gut microbiota in H. cichorii or other Coleoptera insects, as well as the artificial rearing of blister beetles.

Osmoregulation by sucrose isomerization in the phloem-feeding whitefly Bemisia tabaci involves members of the glycoside hydrolase family 13.

A phloem-sap based diet requires unique enzymatic skills for regulating the osmotic pressure differences in the gut lumen between the sucrose-rich ingested sap and the body fluids, which can lead to desiccation and death. In the phloem-feeding whitefly Bemisia tabaci, members of the glycoside hydrolase family 13 (GH13) are likely to play a critical role in mitigating this risk by oligomerizing and isomerizing the products of sucrose hydrolysis. So far, however, the identities of the family members acting as sucrose isomerases (mainly isomerizing trehalulose) remain unknown. In this study, we focused on four putative sucrose isomerase coding genes of B. tabaci that belong to the GH13 family. The four coding genes were selected based on their phylogeny, expression patterns, and motif analyses. We used artificial diets of sucrose and dsRNA to knockdown the expression of each of the target genes and analyzed the sugar composition of the secreted honeydew. We found that in all cases, gene silencing resulted in a significant reduction of the fractions of trehalulose accompanied by an increase in the fractions of the trisaccharide melezitose, suggesting that the insects attempt to compensate for the inability to isomerize sucrose by synthesizing oligosaccharides. In addition, we found that the downregulation of the target genes also resulted in a significant increase in the mortality rates of the silenced insects and a significant delay in the development of their progeny. Taken together, these findings demonstrate the importance of the osmoregulation-by-isomerization strategy in B. tabaci.

Atmospheric cold plasma alters plant traits and negatively affects the growth and development of fall armyworm in rice

Plasma is considered as the fourth state of matter, and atmospheric cold plasma (cold plasma) is a type of plasma consisting of ionized gases containing excited species of atoms, molecules, ions, and free radicals at near room temperature. Cold plasma is generated by applying high voltage to gases, causing it to ionize thus forming plasma. Although cold plasma has been found to break seed dormancy and improve germination rate, only a few studies have explored the potential of cold plasma against insect herbivory. Given that cold plasma produces reactive oxygen and nitrogen species that can activate plant signalling molecules, it is plausible that cold plasma can have differential effects against insect herbivores. To test this, we evaluated the effectiveness of cold plasma on a polyphagous lepidopteran pest, Fall armyworm (FAW) [Spodoptera frugiperda (Lepidoptera: Noctuidae)] on rice (Oryza sativa L.) using an atmospheric plasma jet reactor that generated cold plasma using ambient air as the source gas. We treated rice seeds from two commonly grown Arkansas cultivars (Jewel and Diamond) with cold plasma, followed by irrigation with Cold Plasma-Activated Water (PAW). We then independently tested FAW growth on an artificial diet partially made with PAW. Our results show that cold plasma significantly affected the feeding, growth, and development of FAW, irrespective of the rice varieties. The effects of cold plasma treatment resulted in reduced damage by FAW, lower mass gain and longer pupation period on FAW compared to the untreated control. However, the effects of cold plasma on rice growth and development were dependent on the rice varieties. Cold plasma treatment also induced detrimental effects on FAW leading to ~ 25% mortality on cold plasma-treated plants when compared to untreated controls. Collectively, these findings offer significant evidence of the potential of cold plasma as a novel component for sustainable pest management.

Salvia connivens Methanolic Extract Against Spodoptera frugiperda and Tenebrio molitor and Its Effect on Poecilia reticulata and Danio rerio

Spodoptera frugiperda (Lepidoptera: Noctuidae) and Tenebrio molitor (Coleoptera: Tenebrionidae) are two prominent pests of maize and its stored grains, respectively. Botanical pesticides have been proposed as an alternative for their management. This study evaluated the insecticidal activity of Salvia connivens (Lamiaceae) methanolic extract and rosmarinic acid against S. frugiperda and T. molitor by adding them to an artificial diet, as well as their ecotoxicological effects on Poecilia reticulata (Cyprinodontiformes: Poeciliidae) and Danio rerio (Cypriniformes: Danionidae) through acute toxicity tests. The methanolic extract showed higher mortality activity against S. frugiperda (LC50 = 874.28 ppm) than against T. molitor (LC50 = 1856.94 ppm) and was non-toxic to fish. Rosmarinic acid, the most abundant compound in the extract (80.45 mg g−1), showed higher activity against S. frugiperda (LC50 = 176.81 ppm). This compound did not cause a toxic effect on adult P. reticulata at the tested concentrations. However, in P. reticulata fingerlings and D. rerio adults, it was non-toxic, except in D. rerio embryos, where it was slightly toxic. These findings suggest that S. connivens methanolic extract has potential as a botanical product for the management of S. frugiperda and T. molitor with low ecotoxicological impact, while rosmarinic acid may be a useful compound for the management of S. frugiperda.

Unveiling the feeding response of Spodoptera litura to natural host and artificial diet

AbstractBehavioral studies play a crucial role in assessing food utilization in insects. However, there exists a gap in our understanding of the phenotypic plasticity in Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) and how it impacts their growth, development, and potential for plant damage. This study aimed to investigate the phenotypic plasticity of S. litura, with a focus on its immature stages, and evaluate the consequences of plant damage and pest management. We conducted in vitro experiments using both a standard artificial diet and tobacco (Nicotiana tabacum L., Solanaceae) plants to assess the growth, development, survival, longevity, reproductive capacity, and egg‐laying capability of S. litura larvae and adults. A type II functional response was estimated for all larval instars, utilizing the Likelihood Holling's Disk model, which provided two key coefficients: the search rate (a) and handling time (Th). Our findings revealed that sixth instars exhibited exceptional agility and efficiency, requiring the shortest time to process each milligram of diet compared with other larval stages. Moreover, when larvae were fed on tobacco, they displayed the shortest developmental time and the highest fecundity. This trend extended to pupal weight, pupal duration, pupal emergence, fecundity, and longevity, which were all significantly higher in individuals fed on tobacco. Additionally, S. litura larvae that fed on tobacco exhibited greater efficiency in converting digested food and lower approximate digestibility compared to larvae fed the artificial diet. These results underscore the importance of focusing on the management of fourth, fifth, and sixth instars, which have the potential to cause severe plant damage. Understanding the functional and nutritional response of S. litura larvae enhances the efficiency of integrated pest management strategies (IPM) at early stages while minimizing ecological impact.

Proteomic Variation in the Oral Secretion of Spodoptera exigua and Spodoptera littoralis Larvae in Response to Different food Sources

The Spodoptera genus is defined as the pest-rich genus because it contains some of the most destructive lepidopteran crop pests, characterized by a wide host range. During feeding, the caterpillars release small amounts of oral secretion (OS) onto the wounded leaves. This secretion contains herbivore-induced molecular patterns (HAMPs) that activate the plant defense response, as well as effectors that may inhibit or diminish the plant’s anti-herbivory response. In this study, we explored the protein components of the OS of two Spodoptera species, Spodoptera exigua and Spodoptera littoralis. We identified 336 and 276 proteins, respectively, with a major role in digestion. Using a label-free quantitative proteomics approach, we investigated changes in protein abundance in the OS of both species after switching from a laboratory artificial diet to detached pepper and tomato leaves. Several proteins, such as various lipases, polycalin and a β-1,3-glucan binding protein, were more abundant in the OS of leaf-fed larvae in both species. Conversely, a tryptophan-aspartic acid (WD)-repeat containing protein significantly decreased upon feeding on plant leaves in both species. Phenotypic plasticity dependent on each Spodoptera-plant combination was observed for several peptidases, potentially related to the need to overcome the effects of proteinase inhibitors differentially produced by the two plant species, and for several REPAT proteins, possibly related to the specific modulation of each Spodoptera-plant interaction. Altogether, our results provide useful information for understanding the interaction of these two polyphagous Spodoptera species with the host plants, and help to identify evolutionary traits that may influence the outcome of herbivory in each of these two related species.

Diet Diversification in Bombyx mori Larvae: The Impact of Dandelion on Nutritional and Bioactive Profiles for Targeted Farming Goals

The domesticated silkworm, Bombyx mori, reared for sericulture, has gained attention as a promising, sustainable protein source. While studies have focused on pupal powders obtained through natural or artificial mulberry-based diets, this research builds on ethnoentomological knowledge of the use of dandelion as a short-term mulberry substitute, in a mixed mulberry–dandelion diet throughout larval development. Through proximate analyses, amino acid and fatty acid profiling, mineral and carbohydrate composition, as well as antioxidant activity assays, we investigated how dietary variation affects B. mori larvae. The mixed diet achieved a distinct nutritional profile, increasing total amino acids to 38.40 g/100 g compared to 32.37 g/100 g in the mulberry-only group, with differences in the content of essential amino acids like isoleucine (2.24 vs. 1.42 g/100 g) and phenylalanine (3.34 vs. 2.82 g/100 g). It also elevated linolenic acid to 74.33% of total fatty acids and introduced sorbitol (13.35 mg/g). Those two compounds were not detected in the larvae reared on a single-plant diet. HPLC-DAD analysis revealed phenolic acids, flavonoids, and riboflavin in both groups, which may serve as potential carriers of antioxidant activity. These preliminary findings demonstrate how dietary modifications can change nutritional profiles and antioxidant properties of B. mori. At the same time, they lay the foundation for further research to fully understand diet-induced effects in edible insects.

Evaluation of different diets for dsRNA-based gene silencing assays in brinjal shoot and fruit borer, <i>Leucinodes orbonalis</i>

The shoot and fruit borer of eggplant, Leucinodes orbonalis, is known to cause huge crop losses and reduce the marketability of the produce. In the current scenario of increased insecticide resistance in pests and concern for ecological sustainability, pest management using target-specific biomolecules such as double-stranded RNA (dsRNA) can be an efficient strategy. To conduct the preliminary lab studies using dsRNA, a diet used for bioassays is crucial as it should support insect growth and development while efficiently delivering the test material. The present study evaluated Artificial Diet (AD) and Potato Diet (PD) through a life table study. The stability of the dsRNA in the diets was assessed at 6, 12 and 24 h post mixing with the diets. The insect survival (62.6%), fecundity (65.48±3.15), sex ratio (1.3:1), and developmental parameters like net reproductive rate were found to be better for PD-reared individuals in comparison to AD-reared insects. The dsRNA was found to be stable for 24 h in AD, while it degraded at 12 h post mixing in PD. Therefore, the AD diet can be used for dsRNA oral feeding and can be replaced with a new diet at every 24 h, and for further rearing after dsRNA feeding, the PD can be used.

Winter fruit contribution to the performance of the invasive fruit fly Drosophila suzukii under different thermal regimes.

Polyphagous insect species develop using multiple host plants. Often considered beneficial, polyphagy can also be costly as host nutritional quality may vary. Drosophila suzukii (Matsumura) is an invasive species that can develop on numerous fruit species over the annual cycle. Here, we assessed the contribution of winter-available fruit to the development of seasonal populations of D. suzukii, under fluctuating late winter/early spring temperature regimes. We infested an artificial diet and three suitable fruit species available in winter/early spring (Aucuba japonica, Elaeagnus ×submacrophylla, Viscum album) with D. suzukii larvae under three temperature regimes: constant 20 °C, fluctuating controlled regime of 8-15 °C (12 h of light at 8 °C and 12 h of dark at 15 °C), and uncontrolled outdoor regime during spring. As expected, fly performance was impaired by early spring-like environmental conditions, whatever the development diet, and the winter fruit were suboptimal diets compared to the artificial diet, whatever the thermal regime. However, under cold fluctuating temperature regimes, the ranking of fruit supporting the best performance changed, highlighting the occurrence of physiological trade-offs. Winter-acclimated females preferentially oviposited in A. japonica and/or E. ×submacrophylla, whatever the thermal regime, which does not support the preference-performance hypothesis. This finding is also discussed in the context of D. suzukii management strategies.

Development and reproduction of Grapholita molesta (Lepidoptera: Tortricidae) on the 3 artificial diets in the laboratory.

Grapholita molesta (Busck) (Lepidoptera: Tortricidae) is a major pest of many fruit trees. The large-scale artificial propagation technology of the insect is the basis for the field application of the sterile insect technique and biological control products based on host mass reproduction. However, a low-cost diet with easily accessible materials remains lacking. In this study, we assessed the insect rearing performance feeding on 3 artificial diets: D1: an artificial diet based on wheat bran and soybean powders; D2: an artificial diet based on soybean powder, maize powders, and tomato sauce; and D3: an artificial diet based on soybean powder, maize powder, tomato sauce, and wheat bran, with apples as a control, using 2-sex life table. At 26 ± 1 °C, 70 ± 5% humidity, and 16:8h L:D photoperiod, the biological indicators of G. molesta fed D1 were consistent with those fed apples, with a larval stage of 14.88 d, a pupal stage of 7.57 d, adult longevity of 22.69 d, egg deposition count of 223.22, intrinsic rate of increase (r) of 0.1359, finite rate of increase (λ) of 1.1456, and net reproductive rate (R0) of 94.50. D1 was used to continuously rear G. molesta population for 5 generations, all life parameters remained normal. These results indicated that the artificial diet based on wheat bran and soybean powder could be used for rearing of the insect. This study proposes an available and cost-effective artificial diet for G. molesta, facilitating the application of green prevention and control technology.

Influence of different temperatures and diets on the life cycle of invasive species Conogethes punctiferalis.

Understanding the interactive effects of temperature and diet on insect life cycles is crucial for effective pest management. Here, the influence of different temperatures and diets on the life cycle of Conogethes punctiferalis was investigated using the age-stage, two-sex life table analysis. The results support the hypothesis that temperature and diets (maize, apple, and artificial diet) significantly influence the entire life cycle performance of C. punctiferalis. The duration of larval development was significantly prolonged, whereas adult lifespan was shortened and showed lower reproductive capacity on apple and artificial diet than maize. The total pre-oviposition period was longer on apples than on maize and artificial diet at both temperatures (20, 26°C). The highest r (0.113 d-1), λ (1.128 d-1), R0 (57.213) , and GRR (75.54) of C. punctiferalis were found on maize at 26°C, while the highest T (45.062) was found on apples. Similar results were obtained in the age-specific survival curves (sxj), fecundity (mx), maternity (lxmx), and reproductive value (vxj) of YPM on different host plants when exposed to 20°C. These findings highlight the need for further research into the complex interactions between temperature, diet, and insect life history traits to develop effective pest management strategies and enhance our understanding of insect ecology in agroecosystems.

Diet particle size influences tropical house cricket life history

Abstract Artificial diets are costly to produce, so diet efficiency is critically important to the success of mass rearing insects. One way to improve feed efficiency is through dietary particle size optimization. We tested whether individual crickets (Gryllodes sigillatus) reared on diets of different particle sizes (0.088-0.125 mm, 0.5-0.7 mm, and 1.0-1.4 mm) would grow differently. Crickets fed a diet ≥0.5 mm grew heavier during the first three weeks but weighed the same after six weeks regardless of diet size. We also tested for dietary size preference, and given a choice crickets consumed the most feed from the 1.0-1.4 mm diet. Next, we tested whether grinding diet to a powder and also pelleting the powder could influence life history. Powdered diet did not influence growth or development, but crickets fed a 2 mm pelleted diet grew larger body size. Overall, our results demonstrate that diet particle size can be leveraged to enhance cricket life history traits important to mass production, as growth was accelerated on larger particle size diets and crickets preferred to eat larger-sized diets. Researchers focusing on physical properties of insect diets should carefully consider the timing of growth and development milestones through which diet particle size may influence feed efficiency.

Functional Analysis of Genes Encoding Juvenile Hormone Receptor Met and Transcription Factor Kr-h1 in the Reproductive Capacity of Coccinella septempunctata Males.

This study focuses on the regulatory effects of genes encoding the juvenile hormone (JH) receptor methoprene-tolerant (Met) and transcription factor krüppel homolog 1 (Kr-h1) on the reproductive capacity of Coccinella septempunctata male adults. Met and Kr-h1 expression levels were analyzed in males fed on artificial diets with and without JH by quantitative real-time PCR, and the effects of Met and Kr-h1 on male reproduction were analyzed by RNA interference technology. Met transcription levels in 5- and 10-day-old males fed with a JH-supplemented diet were lower than those without JH. Kr-h1 expression in 5-day-old adult males was lower in diets lacking JH but was higher in 10-day-old males fed on a diet lacking JH. There were no significant differences in the testes sizes of male ladybugs injected with Met-dsRNA when compared to GFP-dsRNA; however, the testis volume of ladybugs injected with Kr-h1-dsRNA was smaller than those injected with GFP-dsRNA. After males were injected with Met-dsRNA and Kr-h1-dsRNA, the mean egg production by females decreased by 12.75% and 23.10%, respectively, at 20 d postinjection. Our results show that Met and Kr-h1 have important roles in regulating reproduction by directly affecting testes development in males and egg production in females.

Efficacy of azithromycin in alternative chemical management of the fruit flyDrosophila melanogaster (Meigen) (Diptera: Drosophilidae) reared on an artificial diet

Efficacy of azithromycin in alternative chemical management of the fruit flyDrosophila melanogaster (Meigen) (Diptera: Drosophilidae) reared on an artificial diet

Implementing a fishery improvement programme to manage the common cuttlefish (Sepia officinalis) in artisanal sea and lagoon fisheries: The case study of the Chioggia’s fleet

In the light of reducing the impact of fishery, artisanal fisheries hold great potential to achieve the sustainable use of marine resources if locally managed at sub-regional level (i.e., within the same province or fleet) and by implementing mitigation systems. The Chioggia small-scale fishing fleet represents a study case in an overexploited Mediterranean sub-region, operating both in the Venice Lagoon and the North Adriatic Sea. During the spawning period, this small-scale fishery targets the same target species, the common cuttlefish (Sepia officinalis), which, over the past thirty years, has shown a general decline in catch trends. Cuttlefish represent a high-value resource at all life stages, with both adults and juveniles considered targets of the artisanal fishery. Additionally, eggs are consistently laid on fishing gear during the breeding season and must be removed by fishers to prevent a reduction in fishing efficiency. These aspects contribute to the vulnerability of the common cuttlefish stocks, calling for a complementary management approach. We researched methods from the peer-reviewed literature, and adapted methods to reflect the environmental conditions of the sea and lagoon, and small-scale fishing methods. We combined into a complementary management approach: i) mitigation systems to reduce and collect eggs discarded during fishing operations, ii) semi-natural juvenile rearing diets to potentially release fishing pressure and support natural population, and iii) small-scale supply chain to both raise awareness about this resource vulnerability and promote the activity of fishers adopting virtuous behaviours. We tested these three functional management units in collaboration with lagoon and sea fishers and local stakeholders. We showed that the use of egg collectors, as an alternative spawning structure, performed well to limit the loss of the eggs laid upon the fishing gears. Second, we showed that Mixed and Natural diets contributed significantly to the growth rate of hatchlings compared to artificial diets. Finally, we demonstrated a shared interest in products derived from sustainable fisheries from the public, fishers and retailers. Therefore, the small-scale supply chain can represent a valid component to valorise the adoption of the whole management scheme. Overall, this complementary management approach can be adapted to and implemented in other local socio-economic communities of artisanal fishing in coastal environments worldwide. Complementary mitigation systems could work in synergy, overcoming the limitations of individual mitigation measures applied to diverse fishery resources.

The Effect of Different Thermal Treatments on The Chemical Composition and Amino and Fatty Acids Profiles in Fish Artificial Diets

The Effect of Different Thermal Treatments on The Chemical Composition and Amino and Fatty Acids Profiles in Fish Artificial Diets

A novel tank-mix formulation increases the efficacy of alphabaculoviruses on different phylloplanes.

Spodoptera littoralis Boisduval (Lepidoptera: Noctuidae) and Spodoptera exigua Hübner (Lepidoptera: Noctuidae) pose substantial threats to many crops, necessitating the exploration of biopesticides as potential chemical alternatives. One alternative is baculoviruses; however, their instability in the field has hindered their widespread use. Host plant phylloplane affects baculovirus activity at varying levels in different host plants. Formulation contributes significantly to optimizing the baculoviral stability on different phylloplanes against environmental conditions; however, it is expensive and difficult to make in developing or nondeveloped countries. In the current study, we developed a simple tank-mix application (MBF-Tm5) for immediate use, resembling the characteristics of a suspension concentrate formulation for Spodoptera littoralis nucleopolyhedrovirus (SpliNPV) and Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV). We examined their biological activity against 2nd instar larvae first on an artificial diet under laboratory conditions and on eggplant and pepper phylloplane in greenhouse conditions compared to plain viruses. This formulation exhibited no significant improvement in the biological activity of both viruses on an artificial diet under laboratory conditions but significantly improved the biological activity of both viruses on both plants under greenhouse conditions. The original activity remaining (OAR%) of both unformulated and formulated viruses decreased over time under greenhouse conditions; however, the OAR value of both viruses on eggplants was significantly higher than on pepper plants. Overall, the tank-mix simple formulation of baculoviruses might be a great alternative for improved stability in nature, providing better control.

Optimal sugar components provide essential cues for the formation of host‐specialised cotton‐melon aphids

Abstract Host specialisation is a common phenotype in herbivores and is considered as an important driver for species diversity of herbivores. Previous studies have revealed that a distinct plant defence mechanism underlies herbivores' host specialisation. However, the role of plant nutritional status, especially sugar metabolism, is a widely overlooked driver of host specialisation formation. Here, the Cucurbitaceae biotype (CA) and Malvaceae biotype (MA) of cotton‐melon aphids, Aphis gossypii, were used to reveal the potential role of plant sugar metabolism in the formation of host‐specialised aphid biotypes. The abundance, intrinsic rate of increase and net reproductive rate of CA and MA biotypes significantly decreased after reciprocal host transfer, suggesting a host utilisation trade‐off between these biotypes. Further analysis of sugar quality showed differences in sugar components, especially raffinose‐family oligosaccharides (RFOs), between watermelon and cotton plants. The concentrations and ratios of raffinose and stachyose were higher in watermelon leaves than in cotton leaves, respectively. Exogenous application of different sugar substrates showed that CA biotypes performed the best on artificial diets with sucrose and raffinose (3:8) while MA biotypes established populations on artificial diets with only sucrose. Moreover, the level of aphid's galactosidase activity, a key enzyme in RFOs metabolism, decreased in CA biotypes but increased in MA biotypes after reciprocal host transfer for acclimatising themselves to changes in RFOs of host plants. Consequently, optimal sugar components provide essential cues for the formation of host‐specialised cotton‐melon aphids.