<p class="first" id="d19611165e192">Current pesticide risk assessment for bees relies
on a single (social) species, the
western honey bee, Apis mellifera L. (Hymenoptera: Apidae). However, most of the >20,000
bee species worldwide are solitary. Differences in life history traits between solitary
bees (SB) and honey bees (HB) are likely to determine differences in routes and levels
of pesticide exposure. The objectives of this review are to: 1) compare SB and HB
life history traits relevant for risk assessment; 2) summarize current knowledge about
levels of pesticide exposure for SB and HB; 3) identify knowledge gaps and research
needs; 4) evaluate whether current HB risk assessment schemes cover routes and levels
of exposure of SB; and 5) identify potential SB model species for risk assessment.
Most SB exposure routes seem well covered by current HB risk assessment schemes. Exceptions
to this are exposure routes related to nesting substrates and nesting materials used
by SB. Exposure via soil is of particular concern because most SB species nest underground.
Six SB species (Hymenoptera: Megachilidae - Osmia bicornis L., O. cornifrons Radoszkowski,
O. cornuta Latreille, O. lignaria Say, Megachile rotundata F., and Halictidae - Nomia
melanderi Cockerell) are commercially available and could be used in risk assessment.
Of these, only N. melanderi nests underground, and the rest are cavity-nesters. However,
the three Osmia species collect soil to build their nests. Life history traits of
cavity-nesting species make them particularly suitable for semifield and, to a lesser
extent, field tests. Future studies should address basic biology, rearing methods
and levels of exposure of ground-nesting SB species.
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