Pollen Gathering
My research in this area is published in the Journal of Hymenoptera Research, "A review and updated classification of pollen gathering behavior in bees (Hymenoptera, Apoidea)" https://doi.org/10.3897/jhr.71.32671 How a bee gathers pollen depends on many factors, including the structure of the host flower, the location of the pollen, and the behavioral and evolutionary limitations of the bee. I am interested in documenting the different types of pollen gathering behaviors and how they evolved. In particular, I am exploring the link between different floral and pollen morphologies and how they affect pollen gathering behavior in different bee species. |
Active vs. incidental pollen gathering
Active pollen gathering occurs when when pollen is the primary objective or when nectar (or oil) and pollen are co-objectives. Active pollen gathering can be broken down into six types: scraping with the extremities, buzzing, rubbing with the body and/or scopa(e), tapping, rubbing with the face, and rasping. Each type is broken down below.
Incidental pollen gathering occurs when pollen accumulates on the body, EITHER when a bee nectaring OR performing a primary pollen gathering behavior and pollen accumulates on non-target areas of the body.
Active pollen gathering occurs when when pollen is the primary objective or when nectar (or oil) and pollen are co-objectives. Active pollen gathering can be broken down into six types: scraping with the extremities, buzzing, rubbing with the body and/or scopa(e), tapping, rubbing with the face, and rasping. Each type is broken down below.
Incidental pollen gathering occurs when pollen accumulates on the body, EITHER when a bee nectaring OR performing a primary pollen gathering behavior and pollen accumulates on non-target areas of the body.
The different types of active pollen gathering behavior:
Incidental pollen gathering occurs when pollen accumulates on the body, EITHER when a bee nectaring OR performing a primary pollen gathering behavior and pollen accumulates on non-target areas of the body. The bee then “decides,” based on pollen and floral characteristics, and on need, to discard or keep the pollen. This is demonstrated in the video where both honey bees are gathering pollen incidentally, but only one of them is currently packing the pollen into the pollen-transporting structures. Temporarily accumulating pollen is a behavior that doesn't fit into the active/incidental dichotomy, but it is an important and under-appreciated behavior performed by many different bees. Temporarily accumulating pollen is a two-step process that first involves the accumulation of a large amount of pollen on a specialized hair patch (as opposed to generalized body hairs). Then after a sufficient quantity of pollen has accumulated on the specialized hair patch, it is transferred to the pollen-transporting structures. This behavior is most well-documented in panurgine bees, but it has also been observed in many other groups such as Trigona and various Melittidae. There are two videos to demonstrate this behavior. The first video shows panurgine bees, led off Perdita sphaeralceae. Note how the bee first uses the forelegs to gather pollen onto the venter of the thorax, then it rears back and transfers the pollen to the hind legs. This same behavior is shown for other bees on various flowers, including Perdita minima, Perdita multiflorae, Macrotera mortuaria, and Calliopsis subalpina. The next video shows two melittid bees temporarily accumulating pollen. First is Macropis, which initially gathers pollen by rubbing with the venter of the thorax and abdomen, and then transfers the accumulated pollen in flight. Next is Hesperapis on Eucnides, which initially accumulated pollen onto a specialized patch of hairs on the venter of the head, and then it flops onto its back and transfers the pollen to the scopa. |
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