Light conditions effect on bird cherry ermine moth - the main pest of bird cherry

This article studies the effect of light and high temperature on various parameters describing the growth and development of bird cherry ermine moth (Yponomeuta evonymellus L.) – the main pest of bird cherry (Prunus padus L.). We found that light significantly influences the moth masses and dynamics of their development. Moths developed from larvae feeding on leaves growing in full light conditions have a higher mass and shorter time of adult eclosion from pupa in comparison with larvae feeding on leaves growing in shade. However, extremely high summer temperature significantly disturbs pupation process in Y. evonymellus population. Our laboratory experiments indicate that a critical temperature is 36°C. Above this threshold the percentage of pupation drastically decreases (from ca. 70% to 35%). The conditions of intensive sun are better for some parameters of growth and development of bird cherry ermine moth. On the other hand, extreme summer temperatures, related with global warming, may restrict the occurrence of Y. evonymellus gradation

Species composition of arthropods on six understory plant species growing in high and low light conditions

The quality of leaves as food for insects is affected both by plant species and the light conditions present during growth. Little information exists concerning the impact of these factors on the diversity of insects that live in the forest understory. We studied arthropod fauna on six understory plant species commonly occurring in Europe. Different groups of herbivorous insects were identified, as well as predatory insects and arachnids. We analysed the influence of both plant species and light conditions during growth (low light; high light) on the species spectrum, and the number of insect specimens present. The resulting data were investigated in relation to the susceptibility of plant leaves to feeding by folivorous insects, as determined in earlier studies. We compared the similarity in species diversity, based on the Sørensen’s coefficient, and discussed the potential causes of observed differences in leaf damages. We found a total of 153 arthropod taxa on studied plants, under both light conditions. Corylus avellana and Prunus serotina, species characterized by greater leaf damage, have a wider diversity of arthropod species, and a greater number of herbivorous insects. Generally, light conditions had a greater effect on arthropod abundance than on species diversity. For two plant species, C. avellana and P. serotina, light conditions strongly, but reversely, influenced the total number of insects and, thus, the extent of leaf damage. The number and abundance of zoophagous species, and ratio to folivores (except C. avellana) are associated more with plant species than with light condition