Role of individual chemical compounds of repellent secretion of Graphosoma lineatum towards different predator species

The chemical defence of Heteroptera is based on the repellent secretion that is very complex and consists of dozens chemical compounds. Heteroptera have good ability to produce/store large amounts of chemical components. The repellent secretion of Graphosoma lineatum is composed of many chemicals, such as short-chained aldehydes, which may signal the unpalatability of the bug to its potential predators or be directly toxic for them. The thesis is aimed at the major components of defensive secretion of Graphosoma lineatum - aldehydes - as well as the whole metathoracic scent-glands secretion of Graphosoma lineatum. The aversive reactions of four selected predators were evaluated: (1) leopard gecko (Eublepharis macularius); (2) green lizard (Lacerta viridis); (3) great tit (Parus major) and (4) blue tit (Cyanistes caeruleus). The following major compounds of the repellent secretion were tested: (1) the mixture of three aldehydes: (E)-hex-2-enal, (E)-oct-2-enal, (E)-dec-2-enal; (2) the mixture of three aldehydes and tridecane; (3) oxoaldehyde: (E)-4-oxohex-2-enal; (4) extracted metathoracic scent-glands secretion of Graphosoma lineatum adults; (5) hexane as a non-polar solvent and (6) pyrazine: 2-isobutyl-3-methoxypyrazine in experiments with leopard geckos as a positive control for excluding the..