Tibial Spurs Dig Nests

yellow and black bee digging in multi-colored pebbles

Biological Strategy

Bees

Holly Kerstiens

Image: Will George / Flickr / CC BY NC - Creative Commons Attribution + Noncommercial

Move in/on Solids

To obtain needed resources or escape predators, some living systems must move on solid substances, some must move within them, and others must do both. Solids vary in their form; they can be soft or porous like leaves, sand, skin, and snow, or hard like rock, ice, or tree bark. Movement can involve a whole living system, such as an ostrich running across the ground or an earthworm burrowing through the soil. It can also involve just part of a living system, such as a mosquito poking its mouthparts into skin. Solids vary in smoothness, stickiness, moisture content, density, etc, each of which presents different challenges. As a result, living systems have adaptations to meet one, and sometimes multiple, challenges. For example, some insects must be able to hold onto both rough and slippery leaf surfaces due to the diversity in their environment.

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Physically Assemble Structure

Living systems use physical materials to create structures to serve as protection, insulation, and other purposes. These structures can be internal (within or attached to the system itself), such as cell membranes, shells, and fur. They can also be external (detached), such as nests, burrows, cocoons, or webs. Because physical materials are limited and the energy required to gather and create new structures is costly, living systems must use both conservatively. Therefore, they optimize the structures’ size, weight, and density. For example, weaver birds use two types of vegetation to create their nests: strong, a few stiff fibers and numerous thin fibers. Combined, they make a strong, yet flexible, nest. An example of an internal structure is a bird’s bone. The bone is comprised of a mineral matrix assembled to create strong cross-supports and a tubular outer surface filled with air to minimize weight.

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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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Bees use small spikes on their legs to dig and create nests.

One way to help classify a bee taxonomically is to investigate the tibial spurs. The tibial spurs stick out from where the tibia meets the basitarsus and can be found on any of the legs, though are most commonly on the hind and midlegs. They’re movable and multiple spurs can be found on the same leg. Small, immovable spikes called tibial spines eject from the spurs.

Tibial spurs are used mainly to dig nests into substrate and they vary according to what material the bees use for nesting substrate. European honeybees (Apis mellifera) don’t have tibial spurs because they build wax combs and have no need to dig.

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.

The tibial spurs of a mining bee, for digging in sandy soils.

Image: Soraya Villalobos / CC BY NC - Creative Commons Attribution + Noncommercial

The tibial spurs of a bumblebee, for digging in colder climates.

Last Updated April 3, 2019

References

“The tibial spurs are the movable inferior apical spurs on the tibiae; there is one spur (part of the strigilis) on the front tibia, one on the middle tibia, and in nearly all bees two on the hind tibia. The tibial spines (Fig. 10-9) are immovable, sharp, superior apical projections, usually small in size, often blunt or minute, found in some bees. There are none, one, two, or rarely three spines per tibia; often they are mere angles.” Michener, 2007:51

Book

The Bees of the World, Second Edition.

Hopkins Fulfillment Service. | Michener CD.

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Reference

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Bombus - Natural History Museum

Natural History Museum

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