Herbivorous insects show different degrees of food specialisation. The food experience during early ontogenetic stages might lead to a fixation of preference for this particular diet later in ontogeny. Moreover, early experience might effect the overall behavioural phenotype. Here it will be investigated, whether a reduction of phenotypic plasticity occurs in two chrysomelid species, a specialist and a generalist. Larvae will be kept on either single or mixed diet differing in quality. Adults will then be tested on various sensory levels (olfaction, contact) for food and oviposition preferences and for risk-proneness. It is postulated that fixation occurs more likely, when larvae are reared on pure compared to mixed food; the specialist might show a fixation more readily than the generalist; and individuals reared on pure quality diet might be more risk-prone. To investigate potential physiological mechanisms, food consumption indices and metabolic rates will be measured. Underlying chemical principles of host recognition will be measured in the different rearing groups to determine, whether a fixation to the food experienced in early ontogeny is adaptive.
To investigate effects of early food conditions on adult behaviour, mustard leaf beetle, Phaedon cochleariae
(Coleptera: Chrysomelidae) (top) and tansy leaf beetle, Galeruca tanaceti
(Coleoptera: Galerucinae) (below), are used. Using a specialist and a generalist herbivorous insect species and manipulating their host plant quality (offering suitable and less suitable hosts), it is tested, under which circumstances behavioural plasticity might become more restricted.
Rearing conditions Contact test