Extrafloral Nectar Consumption and Its Influence on Survival and Development of an Omnivorous Predator, LarvalChrysoperla plorabunda(Neuroptera: Chrysopidae)

Abstract

We examined the role of extrafloral nectar in the ecology of a larval common green lacewing, Chrysoperla plorabunda (Fitch). Larval lacewings were observed foraging freely in cotton fields and almond orchards to quantify their consumption of extrafloral nectar. Extrafloral nectar was a major component of the diet of neonate lacewing larvae foraging on cotton. Extrafloral nectar consumption increased strongly as the local availability of aphid prey declined. Lacewing larvae also fed frequently on extrafloral nectar when foraging in almond orchards. A manipulative diet experiment in the field demonstrated that in the absence of arthropod prey, extrafloral nectar contributed only slightly to neonate lacewing growth and did not support lacewing development. Nevertheless, extrafloral nectar did promote substantial longevity of first-instar lacewing larvae, which were able to maintain a high level of searching activity. Both the field experiment and a laboratory experiment showed that extrafloral nectar provides nutritional benefits that extend beyond those provided by a simple water source. Lacewing larvae are highly omnivorous: they feed on plant-based resources (extrafloral nectar), on herbivorous arthropod prey (e.g., aphids), and on other predatory or omnivorous arthropods.