Phenotypic Plasticity of Cuticular Hydrocarbon Profiles in Insects.

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.

Phenotypic plasticity of mate recognition systems prevents sexual interference between two sympatric leaf beetle species.

Maladaptive sexual interactions among heterospecific individuals (sexual interference) can prevent the coexistence of animal species. Thus, the avoidance of sexual interference by divergence of mate recognition systems is crucial for a stable coexistence in sympatry. Mate recognition systems are thought to be under tight genetic control.

The effect of dietary fatty acids on the cuticular hydrocarbon phenotype of an herbivorous insect and consequences for mate recognition.

The cuticular hydrocarbon (CHC) profile of the mustard leaf beetle Phaedon cochleariae is known to mediate mate recognition and is dependent on food plant species; beetles previously were shown to prefer mates that fed on the same plant species and which have a similar CHC pattern. In order to elucidate whether the pattern of ingested fatty acids affects the CHC pattern of P. cochleariae adults, we fed beetles: (a) with two different host plant species differing in fatty acid profile; and (b) artificial diets differing mainly in their composition of mono-, di-, and triunsaturated fatty acids.

Monitoring of microbially mediated corrosion and scaling processes using redox potential measurements.

The use of redox potential measurements for corrosion and scaling monitoring, including microbially mediated processes, is demonstrated. As a case study, monitoring data from 10years of operation of an aquifer thermal energy storage (ATES) site located in Berlin, Germany, were examined. (Fe(2+))-activities as well as [Fe(3+)]-build up rates were calculated from redox potential, pH, conductivity, temperature and dissolved oxygen measurements.

Looking for a similar partner: host plants shape mating preferences of herbivorous insects by altering their contact pheromones.

The role of phenotypical plasticity in ecological speciation and the evolution of sexual isolation remains largely unknown. We investigated whether or not divergent host plant use in an herbivorous insect causes assortative mating by phenotypically altering traits involved in mate recognition. We found that males of the mustard leaf beetle Phaedon cochleariae preferred to mate with females that were reared on the same plant species to females provided with a different plant species, based on divergent cuticular hydrocarbon profiles that serve as contact pheromones.

Insect egg deposition induces indirect defense and epicuticular wax changes in Arabidopsis thaliana.

Egg deposition by the Large Cabbage White butterfly Pieris brassicae on Brussels sprouts plants induces indirect defense by changing the leaf surface, which arrests the egg parasitoid Trichogramma brassicae. Previous studies revealed that this indirect defense response is elicited by benzyl cyanide (BC), which is present in the female accessory reproductive gland (ARG) secretion and is released to the leaf during egg deposition. Here, we aimed (1) to elucidate whether P.

The role of cuticular hydrocarbons in male mating behavior of the mustard leaf beetle, Phaedon cochleariae (F.).

We investigated the role that cuticular hydrocarbons (CHC) play in sexual communication by the mustard leaf beetle, Phaedon cochleariae (Coleoptera: Chrysomelidae). In laboratory bioassays, male P. cochleariae attempted to copulate with living or freeze-killed females as often as with males.

Starving the competition: a proximate cause of reproductive skew in burying beetles (Nicrophorus vespilloides).

Proximate mechanisms underlying reproductive skew are obscure in many animals that breed communally. Here, we address causes of reproductive skew in brood-parasitic associations of burying beetles (Nicrophorus vespilloides). Male and female burying beetles feed and defend their larvae on buried carcasses.

Perceptual filling-in from the edge of the blind spot.

Looking at the world with one eye, we do not notice a scotoma in the receptor-free area of the visual field where the optic nerve leaves the eye. Rather we perceive the brightness, color, and texture of the adjacent area as if they were actually there. The mechanisms underlying this kind of perceptual filling-in remain controversial.

Surround-induced foveal afterimage pulsation: evidence for a long-range neural effect.

We demonstrate that an afterimage resulting from a strong foveal light flash can be made to pulsate by luminance modulation of a surrounding annulus as far as 8 deg away. Afterimage pulsation persists even if all artifacts due to pupil size, stray light and simultaneous contrast are ruled out. This suggests an origin by a long-range neural process acting from the remote surround.