Landscape fragmentation is also relevant in considering the
dynamics of plant and animal populations in agricultural landscapes
[81]. Kruess and Tscharntke [82] studied several groups
of insect seed feeders in the pods of Vicia sepium and their
parasitoids in an agricultural landscape consisting in patches
of various sizes. They concluded that the patch area was the
major determinant of species diversity and abundance of endophagous
parasites in the seed feeders. Also, colonization
success of the plant pests was greatly reduced in isolated environments.
These results have obvious ecotoxicological relevance.
Phytophagous insects are usual targets of applied insecticides which in most cases also affect their parasitoids.
The complexity of toxic effects on these predator–prey systems
(parasitoid–herbivore host–plant) is further enhanced by the
fragmentation of the habitats where they occur. Similar findings
have been reported in the case of pollinator Apoideae
insects [83] and rape pollen beetles [84].