Pollen Ingestion by Chrysoperla externa (Hagen) Adults in a Diversified Organic Agroecosystem

Abstract

Chrysoperla externa (Hagen) larvae prey on pest insects and mites in agroecosystems, and adults mainly feed on pollen, nectar, and honeydew. Therefore, preserving this lacewing in crop systems depends on having plants that provide these resources. The objectives of this research were to identify pollen grains ingested by Ch. externa adults collected in a diversified organic agroecosystem and to evaluate whether there is a difference in the amount of ingested pollen grains between males and females. The adults of Ch. externa were collected in four different crops during 13 months in Seropédica, state of Rio de Janeiro, Brazil, using a collecting net. The adults were killed and underwent acetolysis, in order to recover the pollen in the gut. A total of 37,441 pollen grains from 19 Angiospermae families were found, besides 16 Pteridophyte spores. Among the recognized pollen grains, those of Poaceae were the majority, both in frequency of occurrence (87.5%) and in quantity (33496), and were found and recovered in every month of collection. Females and males ingested, respectively, 71.9 and 28.1% of the total number of Angiospermae pollen grains consumed by both sexes. The highest number of Poaceae pollens was obtained from the females (72.1% of the total number of Poaceae pollen, recovered from females + males). Taken as a whole, this study showed that adults of Ch. externa find possibilities to maintain throughout the year, in different crops, but the main source of pollen to males and females was Poaceae plants.

Using flower strips to promote green lacewings to control cabbage insect pests

“…To analyse pollen consumption, the acetolysis technique was used for protein, lipid and insect tissue digestion, which facilitated accurate pollen identification (Jones 2014). This methodology has been previously used to study gut content in Chrysopidae adults (Medeiros et al 2010;Andrade et al 2017;Resende et al 2017;Villa et al 2019). Prior to acetolysis, wings, legs and antennae were removed from defrosted adults at room temperature to reduce residues following acetolysis.…”

Pollen and nectar have different effects on the development and reproduction of noctuid moths

“…Generally, flower-visiting and nectar-feeding insects exhibit marked preferences for pollen or nectar from certain plant species and can be attracted by floral volatile compounds (Andrade et al, 2018;Haber et al, 2018;Kessler et al, 2019).…”

Biological parameters of adult of Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae) fed on Asteraceae pollen under laboratory conditions

“…Diversas famílias de plantas são utilizadas para obtenção desses recursos, porém Ch. ext erna possuem uma preferência pela família das Poaceae, mas isso não quer dizer que eles se alimentam somente dessa família, eles também se alimentam de outras plantas que são font e de proteína e carboidratos (FREITAS, 2002;OLIVEIRA et al, 2009;MEDE IROS et al, 2010;RESE NDE et al, 2017;ANDRADE et al, 2018).…”