| Summary: | Predaceous ladybeetles are highly polyphagous predators that ingest supplementary food from flowering plants. Flowering plants widely grown in agroecosystems can sustain multiple natural enemies of agricultural pests, and the pollen and nectar resources from flowering plants may have a positive role in natural enemies. <i>Cnidium monnieri</i> (L.) Cusson, an annual herb with many flowers, blooms from May to July. <i>C. monnieri</i> can support several predatory natural enemies, and the addition of <i>C. monnieri</i> strips increases the density of <i>Harmonia axyridis</i> (Pallas) and improves the biological control of apple aphids in an apple orchard. <i>H. axyridis</i> is also the most important natural enemy in wheat aphid biocontrol and is attracted to healthy and aphid-infested <i>C. monnieri</i> plants. In addition, adult <i>Propylaea japonica</i> Thunberg survives significantly longer on <i>C. monnieri</i> flowers than on a water-only diet. In this study, a laboratory experiment was conducted to assess (i) the effect of nutritional supplements derived from <i>C. monnieri</i> flowers on the development and reproduction of <i>H. axyridis</i> under a wheat aphids-only diet; (ii) the effect of <i>C. monnieri</i> flowers on <i>H. axyridis</i> adult reproduction performance. We compared the larval durations, survival, weight, adult longevity, and reproduction of <i>H. axyridis</i> reared on wheat aphids-only and aphids plus <i>C. monnieri</i> flower diets. The results showed that <i>H. axyridis</i> larvae reared on aphids plus flowers had significantly greater weights and survival rates, shorter larval durations, and produced 1.62 times more eggs than those reared on wheat aphids-only diets. <i>H. axyridis</i> adults ingesting a <i>C. monnieri</i> flowers plus an aphid diet increased egg production 1.44 times compared to the aphids-only diet. Our study demonstrates that <i>C. monnieri</i> flowers as a supplementary food positively affect the survival, development, and reproduction performance of <i>H. axyridis.</i>
|
|---|