Caste and Population Specificity of Termite Cuticule Hydrocarbons

Abstract

The composition of hydrocarbons from the termites Reticulitermes lucifugus Rossi and Kalotermes flavicollis Fabr. belonging to different castes and populations was determined using GC and mass spectrometry. The role of cuticular hydrocarbons in olfactory recognition of termite caste and population status was demonstrated.Insect cuticular hydrocarbons play an exceptionally important role in their lives. They are a component part of the insect exoskeleton and determine many of its properties [1]. Much attention is directed toward the role of cuticular hydrocarbons in insect behavior. Cuticular hydrocarbons are especially significant in social insects [2][3][4], which distinctly differentiate the caste and gender status of individuals [5]. Since the majority of social insects, and termites in particular, live in soil or wood, chemical communication among them is of utmost importance [6]. The nests and tubules of termites are enclosed and their volume is relatively small. Under such conditions, chemical signals should have the ability to transfer large quantities of information and should be relatively involatile in order to decrease the noise levels of information transfer so that the chemicalcommunication system operates effectively. Therefore, termite cuticular hydrocarbons should play an important role in olfactory recognition of the caste, population, and species status of individuals [3, 7-9].The composition of cuticular hydrocarbons of Kalotermes flavicollis Fabr. and Reticulitermes lucifugus Rossi was determined by GC and GC-MS (Tables 1 and 2). The structures of all compounds were established using analytical GC and mass spectrometry. The cuticular hydrocarbons of the studied termite species belong to five classes: normal alkanes, mono-and dimethylalkanes, and mono-and dienes. The hydrocarbon composition of these termite species has much in common and is similar to that of cuticular hydrocarbons of other species [7].We found that the cuticular hydrocarbons of both termite species contained the same set of hydrocarbons for all castes. However, they differed greatly in the quantitative ratios of both pure components and hydrocarbon classes ( Table 3).Analysis of the composition of R. lucifugus cuticular hydrocarbons from various populations showed that termites of all populations also contain qualitatively identical components whereas the quantitative ratios of them, like for termites of different castes, differ (Table 4). The differences in the ratios of different clases are greatest for termites of the Ai-Dere and Magri populations.Our investigation confirms the existence of caste and population specificity for cuticular hydrocarbons of R. lucifugus. The observed differences in the compositions of cuticular hydrocarbons may be the basis for olfactory recognition of the caste and population status of individuals.In order to prove that the specificity of cuticular hydrocarbons is the basis of olfactory recognition of the caste and population status of individuals, we used the recognition reaction of termites f...

Courtship Pheromones in Parasitic Wasps: Comparison of Bioactive and Inactive Hydrocarbon Profiles by Multivariate Statistical Methods

“…Studies on social insects have shown that subtle quantitative differences in cuticular hydrocarbon profiles can be detected by analyzing chemical data with multivariate statistical methods. By this approach, cuticular hydrocarbon profiles of social insects have been shown to be species-(e.g., Kaib et al, 1991;Page et al, 2002), caste-(e.g., Bagnères et al, 1990;Klochkov et al, 2005), and colony-specific (e.g., Butts et al, 1995;Lorenzi et al, 1997).…”

Social Recognition in Invertebrates

“…Therefore, once again, non-volatile chemical signatures on body surfaces are likely to serve as recognition cues and CHCs may potentially be involved. Indeed, several studies focusing on intercaste differences in CHC profiles have detected more or less pronounced caste specificity in CHC signatures, which would allow caste discrimination based on quantitative patterns of CHCs in lower, intermediate, and higher termites (Howard et al 1982a;Haverty et al 1988Haverty et al , 1996Bagnères et al 1990bBagnères et al , 1998Brown et al 1996b;Sevala et al 2000;Klochkov et al 2005). Quantitative caste-specific CHC signatures are neither conserved nor consistent across all colonies of a given species; instead, they change from one colony to the next (Haverty et al 1988).…”