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Author: Admin | 2025-04-28
Primarily to provide their young with a source of protein. Different species of bees require pollen from different plants. Some bees are specialists, relying on pollen from a single or a few closely-related species of plants. For example, in Pennsylvania, three species of melittid bees (species in the genus Macropis) are pollen specialists of loosestrife plants (genus Lysimachia). Notably, these melittid bees also harvest floral oils from the loosestrifes, which are used to line their ground nests and feed their offspring. Many species of mining bees in the state are also pollen specialists. A specialist species that is important for crop pollination in the region is the squash bee (Eucera pruinosa), which relies on pollen from cultivated pumpkins and squash (genus Cucurbita). In contrast, other bee species are generalists, which collect pollen from a wide range of plants. Pollen generalists in the state include many wild species as well as two species commonly used for crop pollination: honey bees and the common eastern bumble bees (Bombus impatiens) (Photos 2C, 3B).At least 13% of the bee species in the state have not been recorded in the past 18 years. These species may be rare or could be in decline. One species of potential conservation concern has not been detected in Pennsylvania since 1911: Epeoloides pilosulus, a cuckoo bee that parasitizes bees in the genus Macropis. An endangered species, the rusty patched bumble bee (Bombus affinis), was last recorded in 2006. Other species of bumble bees that are currently threatened or declining are the American bumble bee (Bombus pensylvanicus) and yellow bumble bee (Bombus fervidus), both last recorded in 2018, and the yellow-banded bumble bee (Bombus terricola) most recently detected in 2009. While these species have been found relatively recently, further studies are needed to determine the status of their and other species' populations within the state.At least 23 exotic bee species are found in Pennsylvania. Some of these species were introduced to North America accidentally, while others were intentionally introduced to provide crop pollination services. Non-native species in the state include the honey bee (Apis mellifera), the alfalfa leafcutting bee (Megachile rotundata), the sculptured resin bee (Megachile sculpturalis), three mason bee species (Osmia caerulescens, Osmia cornifrons, and Osmia taurus), and three wool carder bee species (Anthidium manicatum, Anthidium oblongatum, and Pseudoanthidium nanum) (Photos 3B, 4A–C). Exotic bee species may be beneficial as pollinators of agricultural crops and interesting cases for studying how organisms adapt to new environments. Exotic species may also have negative impacts, such as out-competing native species for food and nest sites, introducing or spreading diseases and parasites, and influencing interactions between plants and their native pollinators. Tracking the distribution of exotic species in the state will allow their
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