Overlooked Scents: Chemical Profile of Soma, Volatile Emissions and Trails of the Green Tree Ant, Oecophylla smaragdina

Abstract

The green tree ant, Oecophylla smaragdina, is one of only two recognized species of weaver ants. While the identity and functions of chemicals produced and emitted by its congener O. longinoda have been studied quite extensively and serve as a valuable model in chemical ecology research, little comparable information is available about O. smaragdina. Although some analyses of chemicals produced and emitted by O. smaragdina have been reported, the literature is fragmentary and incomplete for this species. To address this knowledge gap, and to enable comparisons in the chemical ecology of the two weaver ant species, we here describe diverse chemicals from the cuticle, Dufour’s glands, poison glands, head, headspace volatiles, and trails of O. smaragdina.

Re-Analysis of Abdominal Gland Volatilome Secretions of the African Weaver Ant, Oecophylla longinoda (Hymenoptera: Formicidae)

“…This suggests that further studies to investigate the composition of O. longinoda gland secretions from different populations are necessary to enhance our understanding of gland chemistry. Nonetheless, our results agree with the composition of hydrocarbons recently reported for the poison gland secretions of the Asian weaver ant, O. smaragdina, which identified undecane, tricosane, and heneicosane as the most abundant components of the gland secretions [14], and formic acid previously identified as a major component of the poison gland secretions of carpenter ants (Camponotus spp.) [21]; the lemon ant, Myrmelachista schumanni [22]; and the red wood ant, Formica rufa [23].…”

“…These additional components include a complex mixture of 32 hydrocarbons (51.6%), dominated by unsaturated alkanes, which ranged in chain length from 13 to 25 carbon atoms; saturated alkanes of chain length from 6 to 31 carbon atoms were also detected, as were 12 carboxylic acids (19.4%), dominated by short-chain fatty acids of chain length from two to seven carbon atoms; 5 aldehydes (8.1%); 3 alcohols (4.8%); 2 ketones (3.2%); 4 terpenes (6.5%); 3 sterols (4.8%) and 1 benzenoid (1.6%). Solvent-extracted glands and headspace volatiles gave similar profiles, dominated by hydrocarbons, which were also identified in the gland secretions of O. smaragdina [ 14 ]. However, we found that the headspace volatiles were richer in fatty acids than the solvent-extracted glands.…”

“…These ants possess different glands located in the abdomen, which are used for various purposes [ 12 , 13 ]. The poison gland of Oecophylla longinoda contains a large quantity of formic acid, whereas in O. smaragdina , the key component in the gland secretion is undecane [ 13 , 14 ]. Dufour’s gland, in both species, contains a mixture of hydrocarbons, including undecane and other n-alkanes (decane, dodecane, pentadecane, heptadecane, nonadecane, heneicosane, docosane, and tricosane) [ 13 , 14 ].…”

“…The poison gland of Oecophylla longinoda contains a large quantity of formic acid, whereas in O. smaragdina , the key component in the gland secretion is undecane [ 13 , 14 ]. Dufour’s gland, in both species, contains a mixture of hydrocarbons, including undecane and other n-alkanes (decane, dodecane, pentadecane, heptadecane, nonadecane, heneicosane, docosane, and tricosane) [ 13 , 14 ]. The two major compounds in the glands, formic acid and undecane, are used as an alarm/defense system in O. longinoda [ 13 ].…”

“…This study, which was carried out over four decades ago, used less sensitive analytical chemical techniques based on mass spectrometry fitted with packed glass columns and degradative reactions of isolates obtained from preparative chromatographic analysis to identify compounds. A recent study using modern and more sensitive analytical chemical techniques provided a comprehensive comparison of the chemical profiles of the cuticle, Dufour’s glands, poison glands, the head, headspace volatiles, and trails of a related species, O. smaragdina [ 14 ]. In this study, a total of 59 compounds were identified from these glands of worker ants, including aldehydes, alcohols, carboxylic acid, esters, fatty acids, terpenes, and hydrocarbons.…”