Characterization of fatty acid composition in wax produced by grapevine mealybug, Maconellicoccus hirsutus (Green)

Maconellicoccus hirsutus (Green) is a polyphagous pest with a significant impact on grapevines. This study aimed to characterize the fatty acid composition of the protective wax secreted by M. hirsutus reared on grapevines and potato sprouts using gas chromatography-flame ionization detector. The wax samples from mealybugs and their egg masses revealed a diverse array of methyl esters and hydrocarbons. Key compounds consistently found across all samples included methyl undecanoate, myristoleic acid, gamma-linolenic acid (GLA), and erucic acid. Unique to grapevine-reared specimens were methyl palmito-oleate, gondoic acid, eicosadienoic acid, and eicosatrienoic acid (methyl dihomolinolenate), while potato sprout-reared specimens contained methyl decanoate, methyl heptadecanoate, heptadecanoic acid, and octadecanoic acid. These findings indicate a complex and host-dependent profile of fatty acids in M. hirsutus wax, demonstrating the pest’s biochemical adaptability. GLA emerged as a predominant component, crucial for protecting mealybugs and their eggs from desiccation, and has potential as a dietary source for humans. Methyl undecanoate likely enhances offspring survival through defence mechanisms. Oleic and gondoic acids suggest protective functions in the mealybug wax. Methyl decanoate has antimicrobial properties and suggests defence against microbial threats. Methyl heptadecanoate (margaric acid) plays a role in insect communication and defence, acting as both attractant and repellent. Methyl linoleic acid is essential for reproductive success through sex pheromone synthesis. Erucic acid, present in small amounts, is toxic to many animals and provides hydrophobic and lubrication properties. This detailed characterization of fatty acids enhances our understanding of M. hirsutus’ adaptability and defence mechanisms, offering insights for potential pest control strategies.