Phenylacetaldehyde: A chemical attractant for common green lacewings (Chrysoperla carnea s.l., Neuroptera: Chrysopidae)

Keywords. Neuroptera, Chrysopidae, Chrysoperla, green lacewings, attractant, phenylacetaldehyde Abstract. At five sites in Hungary and Italy, traps baited with phenylacetaldehyde caught significantly higher numbers (10 to 100 times more) of green lacewings than unbaited traps, which demonstrates that this compound is an attractant. Traps with three bait dispensers usually caught more than those with one dispenser, but the difference was significant only at two out of five test sites. There was no difference in the numbers caught by sticky delta and funnel traps baited with phenylacetaldehyde. However, funnel traps could be adapted to catch living green lacewings. The vast majority of the specimens belonged to the Chrysoperla carnea spe- cies complex. Ch. carnea sensu lato dominated the catches at all sites. At some sites 3-11% of the insects caught were Ch. lucasina Lacroix. Phenylacetaldehyde-baited traps were attractive to both sexes, but generally more females were caught than males. Funnel traps baited with three dispensers of phenylacetaldehyde caught green lacewing adults throughout the season in Hungary

Polarization of the Sky

International audienceBased on full-sky imaging polarimetric measurements, in this chapter we demonstrate that the celestial distribution of the angle of polarization (or E-vector direction) of skylight is a very robust pattern being qualitatively always the same under all possible sky conditions. Practically the only qualitative difference among clear, partly cloudy, overcast, foggy, smoky and tree-canopied skies occurs in the degree of linear polarization d: The higher the optical thickness of the non-clear atmosphere, the lower the d of skylight. We review here how well the Rayleigh model describes the E-vector pattern of clear and cloudy skies. We deal with the polarization patterns of foggy, partly cloudy, overcast, twilight, smoky and total-solar-eclipsed skies. We describe the possible influences of the changed polarization pattern of smoky and eclipsed skies on insect orientation. We consider the polarization of ‘water-skies’ above Arctic open waters and the polarization characteristics of fogbows. Finally, we deal with the change of skylight polarization due to the transmission through Snell’s window of the flat water surface