A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat non-vascular autotrophs such as mosses, algae and lichens, but do not include those feeding on decomposed plant matters or macrofungi.
In evolutionary ecology, a parasitoid is an organism that lives in close association with its host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionary strategies within parasitism, distinguished by the fatal prognosis for the host, which makes the strategy close to predation.
Chemical ecology is a vast and interdisciplinary field utilizing biochemistry, biology, ecology, and organic chemistry for explaining observed interactions of living things and their environment through chemical compounds. Early examples of the field trace back to experiments with the same plant genus in different environments, interaction of plants and butterflies, and the behavioral effect of catnip. Chemical ecologists seek to identify the specific molecules that function as signals mediating community or ecosystem processes and to understand the evolution of these signals. The chemicals behind such roles are typically small, readily-diffusible organic molecules that act over various distances that are dependent on the environment but can also include larger molecules and small peptides.
Jasmonate (JA) and its derivatives are lipid-based plant hormones that regulate a wide range of processes in plants, ranging from growth and photosynthesis to reproductive development. In particular, JAs are critical for plant defense against herbivory and plant responses to poor environmental conditions and other kinds of abiotic and biotic challenges. Some JAs can also be released as volatile organic compounds (VOCs) to permit communication between plants in anticipation of mutual dangers.
A hyperparasite, also known as a metaparasite, is a parasite whose host, often an insect, is also a parasite, often specifically a parasitoid. Hyperparasites are found mainly among the wasp-waisted Apocrita within the Hymenoptera, and in two other insect orders, the Diptera and Coleoptera (beetles). Seventeen families in Hymenoptera and a few species of Diptera and Coleoptera are hyperparasitic. Hyperparasitism developed from primary parasitism, which evolved in the Jurassic period in the Hymenoptera. Hyperparasitism intrigues entomologists because of its multidisciplinary relationship to evolution, ecology, behavior, biological control, taxonomy, and mathematical models.
Plant defense against herbivory or host-plant resistance is a range of adaptations evolved by plants which improve their survival and reproduction by reducing the impact of herbivores. Many plants produce secondary metabolites, known as allelochemicals, that influence the behavior, growth, or survival of herbivores. These chemical defenses can act as repellents or toxins to herbivores or reduce plant digestibility. Another defensive strategy of plants is changing their attractiveness. Plants can sense being touched, and they can respond with strategies to defend against herbivores. Plants alter their appearance by changing their size or quality in a way that prevents overconsumption by large herbivores, reducing the rate at which they are consumed.
Herbivores are dependent on plants for food, and have coevolved mechanisms to obtain this food despite the evolution of a diverse arsenal of plant defenses against herbivory. Herbivore adaptations to plant defense have been likened to "offensive traits" and consist of those traits that allow for increased feeding and use of a host. Plants, on the other hand, protect their resources for use in growth and reproduction, by limiting the ability of herbivores to eat them. Relationships between herbivores and their host plants often results in reciprocal evolutionary change. When a herbivore eats a plant it selects for plants that can mount a defensive response, whether the response is incorporated biochemically or physically, or induced as a counterattack. In cases where this relationship demonstrates "specificity", and "reciprocity", the species are thought to have coevolved. The escape and radiation mechanisms for coevolution, presents the idea that adaptations in herbivores and their host plants, has been the driving force behind speciation. The coevolution that occurs between plants and herbivores that ultimately results in the speciation of both can be further explained by the Red Queen hypothesis. This hypothesis states that competitive success and failure evolve back and forth through organizational learning. The act of an organism facing competition with another organism ultimately leads to an increase in the organism's performance due to selection. This increase in competitive success then forces the competing organism to increase its performance through selection as well, thus creating an "arms race" between the two species. Herbivores evolve due to plant defenses because plants must increase their competitive performance first due to herbivore competitive success.
In ecology, a community is a group or association of populations of two or more different species occupying the same geographical area at the same time, also known as a biocoenosis, biotic community, biological community, ecological community, or life assemblage. The term community has a variety of uses. In its simplest form it refers to groups of organisms in a specific place or time, for example, "the fish community of Lake Ontario before industrialization".
Insect ecology is the interaction of insects, individually or as a community, with the surrounding environment or ecosystem. This interaction is mostly mediated by the secretion and detection of chemicals (semiochemical) in the environment by insects. Semiochemicals are secreted by the organisms in the environment and they are detected by other organism such as insects. Semiochemicals used by organisms, including (insects) to interact with other organism either of the same species or different species can generally grouped into four. These are pheromone, synomones, allomone and kairomone. Pheromones are semiochemicals that facilitates interaction between organisms of same species. Synomones benefit both the producer and receiver, allomone is advantageous to only the producer whiles kairomones is beneficial to the receiver. Insect interact with other species within their community and these interaction include mutualism, commensalism, ammensalism, parasitism and neutralisms.
Robert F. Denno (1945–2008) was an influential insect ecologist. He published more than 130 research papers that helped advance the study of plant–insect interactions, interspecific competition, predator prey interactions and food web dynamics. He studied the ecology of sap-feeding insects, both in natural and cultivated settings. His study of wing polymorphism expanded into the fields of life history evolution, plant and herbivore interactions, community ecology, and many aspects of predator ecology, reviewed recently in Denno et al. (2005).
Green leaf volatiles (GLV) are organic compounds released by plants. Some of these chemicals function as signaling compounds between either plants of the same species, of other species, or even different lifeforms like insects.
Plant use of endophytic fungi in defense occurs when endophytic fungi, which live symbiotically with the majority of plants by entering their cells, are utilized as an indirect defense against herbivores. In exchange for carbohydrate energy resources, the fungus provides benefits to the plant which can include increased water or nutrient uptake and protection from phytophagous insects, birds or mammals. Once associated, the fungi alter nutrient content of the plant and enhance or begin production of secondary metabolites. The change in chemical composition acts to deter herbivory by insects, grazing by ungulates and/or oviposition by adult insects. Endophyte-mediated defense can also be effective against pathogens and non-herbivory damage.
Ian Thomas Baldwin is an American ecologist.
Cotesia glomerata, the white butterfly parasite, is a small parasitoid wasp belonging to family Braconidae. It was described by Carl Linnaeus in his 1758 publication 10th edition of Systema Naturae.
Anurag Agrawal is an American professor of ecology, evolutionary biology, and entomology who has written over a 150 peer-reviewed articles, which earned him an h-index of 92. He is the author of a popular science book, Monarchs and Milkweeds from Princeton University Press, and is currently the James Alfred Perkins Professor of Environmental Studies at Cornell University.
Tritrophic interactions in plant defense against herbivory describe the ecological impacts of three trophic levels on each other: the plant, the herbivore, and its natural enemies. They may also be called multitrophic interactions when further trophic levels, such as soil microbes, endophytes, or hyperparasitoids are considered. Tritrophic interactions join pollination and seed dispersal as vital biological functions which plants perform via cooperation with animals.
Naomi Cappuccino is an associate professor of biology at Carleton University in Ottawa, Canada. Her research primarily focuses on population ecology and biological control of invasive species.
John Norton Thompson is an American evolutionary biologist. He is Jean H. Langeheim Professor of Plant Ecology and Evolution at the University of California, Santa Cruz.
Marcel Dicke is a Dutch professor of entomology who has been affiliated with Wageningen University since 2002. He conducts research on insects and has published in the scientific journals Science and Nature. Dicke received the Spinoza Prize in 2007 for his research on the interactions between plants and insects.
Elizabeth A. Bernays was an Australian entomologist who was a Regents Professor at the University of Arizona. She was known for studies of physiological, behavioural, and ecological interactions between plants, herbivorous insects and their predators. Bernays worked on the feeding behaviour of a variety of insects including aphids, grasshoppers, and hawkmoths. She was known for championing the idea that predation drove many insects to specialise on a few species of hostplants, rather than specialisation being solely the outcome of a chemical arms race between plant and insect herbivores.
