Microscopic Identification of Anatomical Elements and Chemical Analysis of Secondary Nests of Vespa velutina nigrithorax du Buyson

Abstract

Vespa velutina accidentally arrived in Europe (France) in 2004, and rapidly expanded throughout the entire country. Its presence in mainland Portugal was first noticed in 2011. Being an invasive species with no natural predators in the region to control it, it has caused enormous environmental and economic damage, particularly on Apis mellifera (honeybee) colonies. Although there is already some research on this species’ biology, little is known about its adaption to European ecological conditions, specifically in terms of nest building. This type of hornet builds a primary nest in the spring to start a colony. During the summer, they build a secondary nest to develop the main colony. These secondary nests are ovoid-shaped and range in size from 18.7 cm to 45.0 cm in diameter and from 19.2 cm to 65.0 cm in length, attaining their highest development in late summer. The external appearance of these nests is characterized by alternating stripes that are beige and brown in color. The main objective of this study is to identify the composition and the origin of the materials that are used by Vespa velutina nigrithorax to build the outer envelope of these secondary nests. This information could be very interesting and will not only increase our knowledge on the biology of the species in regions far from its original area, but will also be relevant for the future implementation of new policies to control this invasive species by means biological control. Several samples were taken from each nest and were observed under different optical magnifying devices. In the second stage, their chemical composition was analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM/EDS). It was noticed that almost all of the materials used in the nests’ construction were lignocellulose from woody materials from both softwood (gymnosperm) and hardwood (angiosperm) forest species as well from leaves and small particles of agricultural origin (grasses). The beige strips were formed almost exclusively from woody softwood cells, while the brown strips were composed of hardwood cells, leaf tissues, and grasses. Chemically, it was noticed that this material mainly consisted of cellulose, with more than 99% being composed of C and O and very little mineral material from elements such as Na, Al, Si, K, and Ca. The achieved results allow us to state that in the construction of these secondary nests, these hornets only used organic materials that are then probably agglomerated through their mouths.

Uncovering floral composition of paper wasp nests (Hymenoptera: Vespidae: Polistes) through DNA metabarcoding

“…We used DNA metabarcoding to identify the plant species used in nest construction by two Polistes wasp species. Most of the plant taxa detected in the nests were woody plants, which is consistent with recent microscopic analysis showing the use of both softwood and hardwood forest species, as well as leaves and small particles of agricultural origin in nest construction 42 . Quercus and Robinia were found to be the most commonly used plants for nest construction by both Polistes species.…”

Investigating the Architecture and Characteristics of Asian Hornet Nests: A Biomimetics Examination of Structure and Materials

“…In a comparative study, a difference was noted in the chemical makeup of the Asian hornet nest paper when compared to N. Crespo et al's [55] research on the same hornet species in a comparable area. N. Crespo et al found that the hornets employed 99% organic matter (C and O), whereas the hornets in this study utilised 97.76% organic matter (C and O).…”

The Little Architect with Its Marvellous Creation: A Study on the Nest Architecture of Tropical Hornet, Vespa affinis

“…Thus, the solid roof cone and its hardened texture coupled with the ability of V. affinis of papering over old cells appear to be characteristic features of the studied nest [18]. The microscopic investigation of the nest material of V. velutina revealed the agglomeration of microelements primarily composed of lignocelluloses spatially arranged into alternating bands of brown and beige stripes [4,19]. The presence of bands of different colours in each papered layer, covering the surface above the nest, provides a spectacular view.…”