Do Bioflavonoids in Juniperus virginiana Heartwood Stimulate Oviposition in the Ladybird Coleomegilla maculata?

Abstract

Maximizing the reproductive potential of ladybird beetles fed factitious foods or artificial diets, in lieu of natural prey, is a major challenge to cost-effective mass rearing for augmentative biological control. In this study, we tested the hypothesis that compounds in redcedar, Juniperus virginiana, stimulate oviposition in the ladybird Coleomegilla maculata. We also tested the prediction that several bioflavonoids, identified in heartwood fractions, elicited this behavioral response. Phenolic compounds were extracted from J. virginiana heartwood sawdust, separated into several fractions, then presented to adult beetles, in a powdered, pure form, in the laboratory. Females preferentially oviposited within 1 to 2 cm of fractions B, C, D, and E, but not A or the unfractionated extract, at the base of test cages. Chemical analysis identified bioflavonoids in heartwood fractions and subsequent bioassays using several identified in fractions C, D, and E confirmed that quercetin, taxifolin, and naringenin (to a lesser extent) stimulated oviposition. All tested fractions and bioflavonoids readily adhered to the chorion of freshly laid eggs but did not reduce egg hatch. This study demonstrates that several bioflavonoids stimulate oviposition by C. maculata and could be useful for mass rearing programs.

Utilization of Quercetin as an Oviposition Stimulant by Lab-Cultured Coleomegilla maculata in the Presence of Conspecifics and a Tissue Substrate

“…In a recent investigation, it was discovered for the first time that three bioflavonoids, quercetin, taxifolin, and naringenin (to a lesser extent), in bioassays in 250 mL cages, stimulated oviposition by C . maculata [ 13 ]. We have expanded our knowledge of the relationship between quercetin and this ladybird in this study.…”

“…The observation that quercetin occasionally increased the number of egg clutches per female in 500 mL solitary cages was expected on the basis of previous research. For example, quercetin and naringenin stimulated slightly more egg clutches per female in 250 mL cages, than in the control cages—lacking any bioflavonoid [ 13 ]. The mechanism of action that triggers the physiological response in females to oviposit in close proximity to quercetin and to occasionally produce more egg clutches is unknown.…”

“…In our recent study, several fractions (containing polyphenols) that were isolated from redcedar heartwood stimulated oviposition by C . maculata in cage bioassays; some of the active fractions were bioflavonoids, such as taxifolin, quercetin, and naringenin (to a lesser extent) [ 13 ]. Additional bioassays using synthetic compounds confirmed the strong, stimulatory effect of taxifolin and quercetin on oviposition by C .…”

Biopesticide synergy when combining plant flavonoids and entomopathogenic baculovirus

“…Analytical methodology. HPLC analysis was conducted following the protocol described in Dowd et al, 2018 andRiddick et al, 2018, on a Shimadzu LC-20 HPLC system (LC-20AT quaternary pump, DGU-20A5 degasser, SIL-20A HT autosampler, and a SPD M20A photodiode array detector, running under Shimadzu LCSolutions version 1.22 chromatography software, Columbia, MD, USA) 13,14 . The column used was an Inertsil ODS-3 reverse phase C-18 column (5 µ, 250 ×4.6 mm from Varian, Palo Alto, CA).…”

“…Five-point standard curves for the evaluation of the concentration of the identified flavonoids in soybean leaves were prepared with commercially purchased kaempferol, genistein, and daidzein for the determination of extinction coefficients at 280 and 340 nm. 13,14 . For phenolic analysis, the initial solvent system was 10% methanol verses water with 0.25% formic acid at a flow rate of 0.25 mL per minute.…”