Phenotypic Plasticity of Cuticular Hydrocarbon Profiles in Insects

Abstract

The insect integument is covered by cuticular hydrocarbons (CHCs) which provide protection against environmental stresses, but are also used for communication. Here we review current knowledge on environmental and insect-internal factors which shape phenotypic plasticity of solitary living insects, especially herbivorous ones. We address the dynamics of changes which may occur within minutes, but may also last weeks, depending on the species and conditions. Two different modes of changes are suggested, i.e. stepwise and gradual. A switch between two distinct environments (e.g. host plant switch by phytophagous insects) results in stepwise formation of two distinct adaptive phenotypes, while a gradual environmental change (e.g. temperature gradients) induces a gradual change of numerous adaptive CHC phenotypes. We further discuss the ecological and evolutionary consequences of phenotypic plasticity of insect CHC profiles by addressing the question at which conditions is CHC phenotypic plasticity beneficial. The high plasticity of CHC profiles might be a trade-off for insects using CHCs for communication. We discuss how insects cope with the challenge to produce and "understand" a highly plastic, environmentally dependent CHC pattern that conveys reliable and comprehensible information. Finally, we outline how phenotypic plasticity of CHC profiles may promote speciation in insects that rely on CHCs for mate recognition.

Adaptations to thermal stress in social insects: recent advances and future directions

“…In insects and other arthropods, CHCs can help limit water loss and the risk of desiccation (Blomquist & Bagnères, 2010; Moussian, 2013). CHC quantity and composition vary greatly based on abiotic and biotic environmental conditions (Gefen et al ., 2015; Nation, 2015; Otte, Hilker, & Geiselhardt, 2018). In social insects, CHCs also serve as signals, largely in the context of nestmate recognition (Greene & Gordon, 2003; d'Ettorre & Lenoir, 2010; Leonhardt et al ., 2016).…”

Cuticular Chemistry of the Queensland Fruit Fly Bactrocera tryoni (Froggatt)

“…Bactrocera tryoni is clearly differentiated from B. neohumeralis in the timing of mating behavior [ 112 ], but the species status of B. aquilonis and B. melas is still debated [ 113 ] and the four taxa differ in their pest status and quarantine restrictions in various jurisdictions [ 113 ]. However, before cuticular chemistry can be used to resolve such taxonomic issues it will be important to investigate the extent to which it can be influenced by diet, maturity and the physical environment [ 114 , 115 , 116 ]. Given the population differences found in Ceratitis rosa [ 55 ], it will also be important to determine whether cuticular chemistry varies between geographic regions and during the course of domestication of species in the B. tryoni complex.…”

Mating has opposite effects on male and female sexually selected cuticular hydrocarbons

“…However, CHCs have been identified in a multitude of arthropods (e.g. Grinsted et al, 2011;Otte et al, 2018;Zhang et al, 2011), and in a subset of these species, sex-specific and sexually selected…”