Why herbivores are important

In the study, the research team used large electric fences to exclude cattle, elephants, zebras and other herbivorous mammals from experimental plots on a ranch in central Kenya from May to December During that time, the scientists monitored changes in the populations of trees, beetles, lizards and other plant and animal species.

These results are examples of what ecologists call cascading effects, he added. Although elephants and zebras do not interact directly with insects, they share plants as a food source, Pringle noted. Previous studies have shown that when elephants and zebras are experimentally removed or hunted out, plant matter accumulates and insect populations increase. The authors also found that the strength of the cascading effects varied considerably across the landscape, and that it was possible to predict where the effects would be weak or strong in terms of "primary productivity"—the transformation of solar energy into plant tissue during photosynthesis.

Plants in areas of high primary productivity grow faster, making more energy available throughout the food chain. The study revealed that cascading effects are weaker in places where productivity is high, probably "because more productive plant communities absorb the impacts of herbivory and buffer the remainder of the community," the authors wrote.

Each of these structures may vary in form between plant species. Herbivores have characteristics that allow them to access these structures. These include:. Plants use complex compounds such as cellulose and lignin to maintain their physical structure and support. These compounds are tough, not water soluble and difficult to digest. Herbivores have employed a number of feeding strategies to overcome these chemical structures and tough plant tissues.

They include:. Plants produce many chemicals for defence against herbivores. These chemicals may kill the herbivore, or deter it from feeding or, in the case of insects, laying eggs on the plant. These chemicals can be made in large quantities and have a secondary use such as structure e.

Herbivores have developed special ways of dealing with defence chemicals. Plants have different stages of growth. For instance, new leaves are growing and roots are extending while elsewhere on the same plant leaves are aging and roots are decaying. At each of these stages the structural and chemical features of plant parts change. For example, younger leaves might have a higher nitrogen content than older leaves.

Because of these changes herbivores, particularly insect herbivores, concentrate in different areas of the plant. Actively growing regions of the plant such as root tips, young leaves and flower buds are nutrient rich. Galls are small swellings on plants often found in these nutrient rich areas. They are caused by insects that live and feed inside the swelling where they are protected from predators and have an ample food supply.

The insect releases chemicals that disrupt the normal processes involved in plant growth resulting in a deformation of the plant tissue - the gall. Common gall formers include flies eg. There are also some non-insect gall formers such as mites and nematodes. There are many invertebrate herbivores. These include snails, slugs, mites, millipedes, worms and species of insects. Insect herbivores are the most numerous and varied. It has been estimated that approximately half of all living insects are herbivores.

Some large insect groups are almost exclusively plant-feeders. These include moths and butterflies, weevils, leaf beetles, gall wasps, leaf-mining flies and plant bugs. The Australian Museum respects and acknowledges the Gadigal people as the First Peoples and Traditional Custodians of the land and waterways on which the Museum stands.

Image credit: gadigal yilimung shield made by Uncle Charles Chicka Madden. This website uses cookies to ensure you get the best experience on our website. Learn more. Skip to main content Skip to acknowledgement of country Skip to footer On this page Toggle Table of Contents Nav What is herbivory? Why is herbivory important? Why are there so many types of herbivore?

Plants and herbivores have developed strong relationships How do herbivores deal with plant defenses? Which invertebrates are herbivores? If a media asset is downloadable, a download button appears in the corner of the media viewer. If no button appears, you cannot download or save the media. Text on this page is printable and can be used according to our Terms of Service. Any interactives on this page can only be played while you are visiting our website.

You cannot download interactives. A food chain outlines who eats whom. A food web is all of the food chains in an ecosystem. Each organism in an ecosystem occupies a specific trophic level or position in the food chain or web. Producers, who make their own food using photosynthesis or chemosynthesis, make up the bottom of the trophic pyramid. Primary consumers, mostly herbivores, exist at the next level, and secondary and tertiary consumers, omnivores and carnivores, follow.

At the top of the system are the apex predators: animals who have no predators other than humans. Help your class explore food chains and webs with these resources. An herbivore is an organism that feeds mostly on plants. Herbivores range in size from tiny insects such as aphids to large, lumbering elephants.

An omnivore is an organism that regularly consumes a variety of material, including plants, animals, algae, and fungi.

They range in size from tiny insects like ants to large creatures—like people. Provided by the Springer Nature SharedIt content-sharing initiative. Advanced search. Skip to main content Thank you for visiting nature. Download PDF. Subjects Palaeoecology. Authors Alicia Newton View author publications.

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