The cicadas are a superfamily, the Cicadoidea, of insects in the order Hemiptera. They are in the suborder Auchenorrhyncha, along with smaller jumping bugs such as leafhoppers and froghoppers. The superfamily is divided into two families, the Tettigarctidae, with two species in Australia, and the Cicadidae, with more than 3,000 species described from around the world; many species remain undescribed. Nearly all of cicada species are annual cicadas with the exception of the few North American periodical cicada species, genus Magicicada, which in a given region emerge en masse every 13 or 17 years.
A keystone species is a species that has a disproportionately large effect on its natural environment relative to its abundance. The concept was introduced in 1969 by the zoologist Robert T. Paine. Keystone species play a critical role in maintaining the structure of an ecological community, affecting many other organisms in an ecosystem and helping to determine the types and numbers of various other species in the community. Without keystone species, the ecosystem would be dramatically different or cease to exist altogether. Some keystone species, such as the wolf and lion, are also apex predators.
This glossary of ecology is a list of definitions of terms and concepts in ecology and related fields. For more specific definitions from other glossaries related to ecology, see Glossary of biology, Glossary of evolutionary biology, and Glossary of environmental science.
The term periodical cicada is commonly used to refer to any of the seven species of the genus Magicicada of eastern North America, the 13- and 17-year cicadas. They are called periodical because nearly all individuals in a local population are developmentally synchronized and emerge in the same year. Although they are sometimes called "locusts", this is a misnomer, as cicadas belong to the taxonomic order Hemiptera, suborder Auchenorrhyncha, while locusts are grasshoppers belonging to the order Orthoptera. Magicicada belongs to the cicada tribe Lamotialnini, a group of genera with representatives in Australia, Africa, and Asia, as well as the Americas.
A frugivore is an animal that thrives mostly on raw fruits or succulent fruit-like produce of plants such as roots, shoots, nuts and seeds. Approximately 20% of mammalian herbivores eat fruit. Frugivores are highly dependent on the abundance and nutritional composition of fruits. Frugivores can benefit or hinder fruit-producing plants by either dispersing or destroying their seeds through digestion. When both the fruit-producing plant and the frugivore benefit by fruit-eating behavior the interaction is a form of mutualism.
Biological dispersal refers to both the movement of individuals from their birth site to their breeding site, as well as the movement from one breeding site to another . Dispersal is also used to describe the movement of propagules such as seeds and spores. Technically, dispersal is defined as any movement that has the potential to lead to gene flow. The act of dispersal involves three phases: departure, transfer, and settlement. There are different fitness costs and benefits associated with each of these phases. Through simply moving from one habitat patch to another, the dispersal of an individual has consequences not only for individual fitness, but also for population dynamics, population genetics, and species distribution. Understanding dispersal and the consequences, both for evolutionary strategies at a species level and for processes at an ecosystem level, requires understanding on the type of dispersal, the dispersal range of a given species, and the dispersal mechanisms involved. Biological dispersal can be correlated to population density. The range of variations of a species' location determines the expansion range.
Anti-predator adaptations are mechanisms developed through evolution that assist prey organisms in their constant struggle against predators. Throughout the animal kingdom, adaptations have evolved for every stage of this struggle, namely by avoiding detection, warding off attack, fighting back, or escaping when caught.
Intraspecific competition is an interaction in population ecology, whereby members of the same species compete for limited resources. This leads to a reduction in fitness for both individuals, but the more fit individual survives and is able to reproduce. By contrast, interspecific competition occurs when members of different species compete for a shared resource. Members of the same species have rather similar requirements for resources, whereas different species have a smaller contested resource overlap, resulting in intraspecific competition generally being a stronger force than interspecific competition.
Optimal foraging theory (OFT) is a behavioral ecology model that helps predict how an animal behaves when searching for food. Although obtaining food provides the animal with energy, searching for and capturing the food require both energy and time. To maximize fitness, an animal adopts a foraging strategy that provides the most benefit (energy) for the lowest cost, maximizing the net energy gained. OFT helps predict the best strategy that an animal can use to achieve this goal.
Competition is an interaction between organisms or species in which both require a resource that is in limited supply. Competition lowers the fitness of both organisms involved since the presence of one of the organisms always reduces the amount of the resource available to the other.
Irruptive growth is a growth pattern over time, defined by a sudden rapid growth in the population of an organism. Irruptive growth is studied in population ecology. Population cycles often display irruptive growth, but with a predictable pattern of subsequent decline. It is a phenomenon typically associated with r-strategists.
Mast is the fruit of forest trees and shrubs, such as acorns and other nuts. The term derives from the Old English mæst, meaning the nuts of forest trees that have accumulated on the ground, especially those used historically for fattening domestic pigs, and as food resources for wildlife. In the aseasonal tropics of Southeast Asia, entire forests, including hundreds of species of trees and shrubs, are known to mast at irregular periods of 2–12 years.
Reproductive synchrony is a term used in evolutionary biology and behavioral ecology. Reproductive synchrony—sometimes termed "ovulatory synchrony"—may manifest itself as "breeding seasonality". Where females undergo regular menstruation, "menstrual synchrony" is another possible term.
Bamboo blossoming is a natural phenomenon in which the bamboos in a location blossom and become hung with bamboo seeds.
A functional response in ecology is the intake rate of a consumer as a function of food density. It is associated with the numerical response, which is the reproduction rate of a consumer as a function of food density. Following C. S. Holling, functional responses are generally classified into three types, which are called Holling's type I, II, and III.
Aggressive mimicry is a form of mimicry in which predators, parasites, or parasitoids share similar signals, using a harmless model, allowing them to avoid being correctly identified by their prey or host. Zoologists have repeatedly compared this strategy to a wolf in sheep's clothing. In its broadest sense, aggressive mimicry could include various types of exploitation, as when an orchid exploits a male insect by mimicking a sexually receptive female, but will here be restricted to forms of exploitation involving feeding. For example, indigenous Australians who dress up as and imitate kangaroos when hunting would not be considered aggressive mimics, nor would a human angler, though they are undoubtedly practising self-decoration camouflage. Treated separately is molecular mimicry, which shares some similarity; for instance a virus may mimic the molecular properties of its host, allowing it access to its cells. An alternative term, Peckhamian mimicry, has been suggested, but it is seldom used.
The match/mismatch hypothesis (MMH) was first described by David Cushing. The MMH "seeks to explain recruitment variation in a population by means of the relation between its phenology—the timing of seasonal activities such as flowering or breeding—and that of species at the immediate lower level". In essence, it is a measure of reproductive success due to how well the phenology of the prey overlaps with key periods of predator demand. In ecological studies, a few examples include timing and extent of overlap of avian reproduction with the annual phenology of their primary prey items, the interactions between herring fish reproduction and copepod spawning, the relationship between winter moth egg hatching and the timing of oak bud bursting, and the relationship between herbivore reproductive phenology with pulses in nutrients in vegetation
A food chain is a linear network of links in a food web, often starting with an autotroph, also called a producer, and typically ending at an apex predator, detritivore, or decomposer. It is not the same as a food web. A food chain depicts relations between species based on what they consume for energy in trophic levels, and they are most commonly quantified in length: the number of links between a trophic consumer and the base of the chain.
Flowering synchrony is the amount of overlap between flowering periods of plants in their mating season compared to what would be expected to occur randomly under given environmental conditions. A population which is flowering synchronously has more plants flowering at the same time than would be expected to occur randomly. A population which is flowering asynchronously has fewer plants flowering at the same time than would be expected randomly. Flowering synchrony can describe synchrony of flowering periods within a year, across years, and across species in a community. There are fitness benefits and disadvantages to synchronized flowering, and it is a widespread phenomenon across pollination syndromes.
Pursuit predation is a form of predation in which predators actively give chase to their prey, either solitarily or as a group. It is an alternate predation strategy to ambush predation — pursuit predators rely on superior speed, endurance and/or teamwork to seize the prey, while ambush predators use concealment, luring, exploiting of surroundings and the element of surprise to capture the prey. While the two patterns of predation are not mutually exclusive, morphological differences in an organism's body plan can create an evolutionary bias favoring either type of predation.
