Male Midlegs Keep Bees Attached While Mating

black and yellow bee against black background

Biological Strategy

Bees

Holly Kerstiens

Image: Sam Droege / Flickr / Public Domain - No restrictions

Attach Temporarily

Living systems must sometimes, temporarily, stay in one place, climb or otherwise move around, or hold things together. This entails attaching temporarily with the ability to release, which minimizes energy and material use. Some living systems repeatedly attach, detach, and reattach for an extended time, such as over their lifetimes. Despite being temporary, these attachments must withstand physical and other forces until they have achieved their purpose. Therefore, living systems have adapted attachment mechanisms optimized for the amount of time or number of times they must be used. An example is the gecko, which climbs walls by attaching its toes for less than a second. Other examples include insects that attach their eggs to a leaf until they hatch, and insects whose wings temporarily attach during flight but separate after landing.

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Expel Solids

Living systems must often discharge solids–such as seeds, eggs, pollen, and mineral salts–for reproduction, protection, or other reasons. Solids can be easily moved when a living system applies force to them. But creating that force requires energy, so living systems must either have efficient strategies worth the energy investment or use an outside force (such as gravity). For example, a tropical mistletoe positions its pollen so that the weight of a bird landing nearby triggers the pollen’s release onto the bird’s forehead. The bird then fertilizes other mistletoes that it visits.

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Insects

Class Insecta (“an insect”): Flies, ants, beetles, cockroaches, fleas, dragonflies

Insects are the most abundant arthropods—they make up 90% of the animals in the phylum. They’re found everywhere on earth except the deep ocean, and scientists estimate there are millions of insects not yet described. Most live on land, but many live in freshwater or saltwater marshes for part of their life cycles. Insects have three distinct body sections: a head, which has specialized mouthparts, a thorax, which has jointed legs, and an abdomen. They have well-developed nervous and sensory systems, and are the only invertebrate that can fly, thanks to their lightweight exoskeletons and small size.

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Male bees use their midlegs to hold onto females while coupling. The legs also have brushes for grooming.

Also known as the mesothoracic leg, the midleg is the second pair of legs on the thorax of the bee. Changes in the midlegs of the bees are often a secondary sexual characteristic, affecting male bees and influencing their chances of finding a mate.

Modified midlegs are often used to hold onto the female as the bee mates with her. Many species mate in midair, so the ability to stay coupled together is important. Midlegs can also contain different coloured brushes and keels used for grooming.

This information is also available from the University of Calgary Invertebrate collection, where it was curated as part of a study on design inspired by bees.

Image: Rob Alexander / CC BY NC - Creative Commons Attribution + Noncommercial

Image: Brooke Alexander / Public Domain - No restrictions

A male Anthophora ursina, with the orange brush on his midleg highlighted.

Last Updated April 3, 2019

References

“In the Hylaeinae and Euryglossinae these [Midleg] brushes are weak and limited to the distal part of the tibia and the base of the femur (and sometimes the trochanter). These bees carry pollen to the nest in the crop, thus eating it rather than transferring it to a scopa. The midleg apparatus therefore probably serves only for grooming. The same is true of many male bees.” Michener, 2007:61

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The Bees of the World, Second Edition.

Hopkins Fulfillment Service. | Michener CD.

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