Temporary Chemical Signals Guide Others

black and yellow bee covered in pollen on a yellow flower

Biological Strategy

Hairy-footed flower bee

AskNature Team

Image: Zac Durant / Unsplash / Free non-commercial use

Send Chemical Signals (Odor, Taste, Etc.)

Tastes, odors, and hormones are all chemical signals that can float through the air or water, or be applied to solid surfaces. Chemicals are important for signaling and communication; even humans, with our underdeveloped sense of smell, are influenced by chemicals more than we realize. Chemical signals are often specific to the living system intended to receive them, and are often relatively weak, dispersing upon moving through liquids or gases. To ensure that chemical signals reach their target, living systems create unique chemical signals and methods of dispersal. One example is an orchid that is pollinated by dung beetles, and therefore distributes a dung-smelling aroma to attract them.

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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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Some species of bees send signals to other bees via temporary scent marks.

“When a bumblebee finds a nectar-rich flower, it tags the blossom with a scent mark, identifying the flower as being worth a return visit. Since bumblebees are social insects that work for the good of the colony, researchers suspect that individual members of a hive leave marks that help their hivemates find the best blossoms.

“Solitary bees are a different story. Foraging only for her own young, each female is in direct competition with all others of the same species. But Francis Gilbert, of the University of Nottingham, and colleagues have shown that solitary bees also rely on scent markings to identify the best food sources…like bumblebees, solitary bees rely on at least two separate components in their scent markings. One is a self-repellent that wears off within about thirty minutes, dissipating as the plant renews its stock of nectar. By the time the flower once again has a full supply, the scent has degraded to the point that the bee is no longer repelled by it. The other component is a short-term attractant, lasting less than three minutes. The scientists suggest that the bee might use this mark if it doesn’t extract all the available nectar during an initial visit, facilitating a return within seconds to finish the job.” (Weir 2001)