A Floral Diet Increases the Longevity of the Coccinellid Adalia bipunctata but Does Not Allow Molting or Reproduction

Abstract

Adalia bipunctata L. (Coleoptera: Coccinellidae) is a generalist aphidophagous coccinellid and an important natural enemy in many agroecosystems including orchards. Coccinellid species have been observed to consume non-prey food like nectar and pollen, but the value of these foods for A. bipunctata is poorly known. The objective of this study was to determine the effect of different prey and non-prey diets on A. bipunctata larval development and adult longevity and fecundity. Larval development was studied on three prey diets: The aphids Dysaphis plantaginea and Myzus persicae and Lepidopteran eggs of Ephestia kuehniella; five flower diets: Matricaria chamomilla, Daucus carota, Fagopyrum esculentum, Anethum graveolens, and Sinapis alba; four pollen diets from three plant species: Typha angustifolia, Malus pumila (two varieties) and A. graveolens; and 1 M solutions of three sugars: glucose, fructose, and sucrose. Adult longevity and fecundity were tested on one prey diet (E. kuhniella eggs), three flower diets (F. esculentum, A. graveolens, and S. alba); the same four pollen diets and three sugar diets with larvae; and finally a mixed diet of sucrose and A. graveolens pollen. A water-only (starvation) control was used for both larval development and adult longevity and fecundity. Adult lipid content was assessed as a measure of how non-prey food affects the ladybeetles' nutritional status. Larvae did not develop beyond the first instar on any of the non-prey diets, but they lived more than twice as long as on F. esculentum and sugar diets than on water. Sugar and flower diets improved A. bipunctata adult longevity (71-92 days and 10-66 days, respectively) over a pure pollen diet (6-7 days). Fecundity was nil on all non-prey diets, and within a normal range on E. kuhniella eggs. The results suggest that pure floral diets do not support A. bipunctata molting or reproduction, but flowering plants can prolong A. bipunctata larval survival and adults longevity considerably when prey are absent. Adults on sugar diets had high lipid content, indicating that sugar feeding can improve overwintering survival. The findings could be used in agroecosystem design, such as the composition of flower strips for optimal functional diversity.

Managing Floral Resources in Apple Orchards for Pest Control: Ideas, Experiences and Future Directions

“…Similar plant species were considered that offer resources in flowers with a short corolla or provide extrafloral nectaries (Table 1). Here, pollen and nectar rewards are easily exploitable by flower visitors with short-tongued or unspecialized mouth parts such as many beneficial flies (Syrphidae, Tachinidae, and others), lacewings, parasitoid Hymenoptera and beetles [14,20,21,22,23,24].…”

“…Natural enemy groups, including those considered exclusively predatory can directly use nectar and pollen provided by flower strips [23,65]. However, in field studies it may be difficult to distinguish between the value of pollen and nectar versus the value of alternative prey and habitat to these predators.…”

Flower diet enhances Adalia bipunctata larval development significantly when prey is limited

“…Besides using a high‐quality prey diet, we also used a high‐quality floral diet, as buckwheat flowers have open nectaries, no documented toxic compounds, and are of high value to predators, including A. bipunctata (Sigsgaard et al, 2013; Bruinsma et al, 2014; Russell, 2015; van Rijn & Wäckers, 2016; He & Sigsgaard, 2019; He et al, 2021). Non‐prey foods can provide supplementary nutrients that sustain coccinellids until they locate prey (Lundgren, 2009a).…”

“…Hemptinne & Desprets (1986) and De Clercq et al (2005) reported that A. bipunctata larvae were able to develop into adults on a pure pollen diet, but with a low survival rate. However, He & Sigsgaard (2019) found that whereas non‐prey diets could prolong survival time for A. bipunctata larvae, larvae did not develop beyond the first instar.…”

Stable Isotope Enrichment (Δ15N) in the Predatory Flower Bug (Orius majusculus) Predicts Fitness-Related Differences between Diets

“…The fitness-related measurements used as reference for diet quality (development time, weight, etc.) are often complemented by biochemical analyses of the body of the predator and/or the prey [1][2][3][4][5][6][7][8][9]. The information on basic components (nitrogen, lipids and carbohydrates) of a given diet can indicate how nutritionally balanced the diet is [10].…”