Pollinating arthropods

Number of compounds Agricultural, forest, and ornamental plant pests Medical, veterinary, and urban pests Predator/ parasites Other/ miscellaneous arthropods Pollinators Total cases by chemical class... 

This high elevation plant diversity harbors extended animal communities which have not been sufficiently well studied. However, in as much as cross pollination and non-wind seed dispersal are fundamental mechanisms for plant species survival, this fauna is of crucial importance to vascular plant life. Although animal life is beyond the scope of the present chapter, the interested reader might find some specific reports instruetive (e.g. Pefaur and Duellman, 1980 Pefaur and Diaz de Pascual, 1985 Vuilleumier, 1986 Hoffstetter, 1986 Cei, 1986 Reig, 1986 Holloway, 1986 Villwock, 1986 Durant et al., 1994 Diaz et al., 1997). As far as arthropods and their influence in secondary plant metabolism, their species diversity has been observed to decline with elevation in some places (e.g. Fleishman et al., 1998). Some exceptions exist as the case of mite s abundance and species diversity in the Appalachians illustrates (Lamoncha and Crossley, 1998). However, more important than species richness to herbivory pressure is the number of individuals forming a herbivore population, a subject that requires further attention in high elevations before a clear picture on their influence on secondary plant metabolism may be assessed properly. 

The majority of resistant species (56.1%) are of agricultural importance, but a substantial proportion (39.3%) represents insects of medical importance, especially mosquitoes and flies. Only 4.6% are beneficial species (predators, parasites, or pollinators) (Table III). For a detailed index of cases of resistance see Georghiou, G. P. Lagunes, A., The Occurrence af Resistance to Pesticides in Arthropods, 2nd d., F.A.O. Rome, in press. 

Honey bees are beneficial arthropods playing a key role in pollinating wild and crop plants. Unfortunately, during their foraging activity they can be exposed to pesticides. The members of the colony can also be poisoned indirectly by contaminated food brought back to the hive by the foragers. The aim of this chapter is to discuss some aspects of the acute toxicity of pesticides to Apis mellifera. 

Furthermore, the widespread use of pesticides has contributed to a further simplification of the agro-ecosystem, which has occurred above all at the expense of insects that are reputedly man s allies, i.e. predators, parasitoids, and pollinators. The latter are often more likely to be harmed by pesticides than the target arthropod pests themselves and thus the exposure to potential infestation by phytophaga increases rather than decreases. 

In contrast to such strong insecticidal activity against lepidopterous insects, pyridalyl showed little insecticidal activity against species of Hemiptera, Coleop-tera and Orthoptera. Such selectivity of the compound is reasonably regarded as a preferable characteristic for uses in I PM programs, because some natural enemy insects are included in those families. In fact, pyridalyl showed minimal impacts on various beneficial arthropods such as parasitic wasps, predatory insects and mite and pollinators (Table 30.3.5) [1, 6, 7]. 

Plant-associated small animals inclnde those arthropods that (i) are in obligate association with plants, (ii) are plant pests, (iii) are plant pollinators,or(iv)transmit plant diseaseagents,as well as othersmallanimals snchas nematodes forwhich tests of biological properties necessitate the use of plants. Microorganisms associated with such small animals (e.g., pathogens or symbionts) are inclnded. 

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