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In general, population growth roughly follows one of these trends: [1] Logistic growth leveling out at some carrying capacity. Overshoot ("boom" and "bust" cycles). Oscillation at or below the carrying capacity. Insect pest growth rates are heavily influenced by temperature and rainfall, among other variables.
For 203 insect species that had IUCN-documented population trends in 2013, 33% were in decline with variation in documented species across orders. [13] Most scientific and public attention has been focused on the conservation of larger, charismatic vertebrates, and relatively fewer studies have been done on insect groups, especially Diptera ...
Using these techniques, Malthus' population principle of growth was later transformed into a mathematical model known as the logistic equation: = (), where N is the population size, r is the intrinsic rate of natural increase, and K is the carrying capacity of the population. The formula can be read as follows: the rate of change in the ...
Decline in insect populations. An annual decline of 5.2% in flying insect biomass found in nature reserves in Germany – about 75% loss in 26 years [1] Insects are the most numerous and widespread class in the animal kingdom, accounting for up to 90% of all animal species. [2][3] In the 2010s, reports emerged about the widespread decline in ...
Allee effects are classified by the nature of density dependence at low densities. If the population shrinks for low densities, there is a strong Allee effect. If the proliferation rate is positive and increasing then there is a weak Allee effect. The null hypothesis is that proliferation rates are positive but decreasing at low densities.
A 1982 study by Templeton and Johnson showed that in a population of Drosophila mercatorum under K-selection the population actually produced a higher frequency of traits typically associated with r-selection. [37] Several other studies contradicting the predictions of r/K selection theory were also published between 1977 and 1994. [38] [39 ...
Economic threshold. In integrated pest management, the economic threshold is the density of a pest at which a control treatment will provide an economic return. [1] An economic Injury is the insect's population level or extent of crop damage at which the value of the crop destroyed exceeds the cost of controlling the pest. [2] Economic ...
Delayed density dependence has been used by ecologists to explain population cycles. [2] Ecologists have been unable to successfully explain regular population cycles for many decades; delayed density dependence may hold the answer. [2] Here populations are allowed to increase above their normal capacity because there is a time lag until ...