A Comprehensive Survey of Population Ecology in Insects
Authors: L Shirani-Bidabadi 
Published: August 2024

Population ecology focuses on studying populations and their relationship with the environment, including parameters such as birth, death, migration, density, and age distribution. Population ecology involves laboratory work, field observations, and the use of mathematical and statistical models to study groups of organisms. By studying populations, researchers gain insights into population dynamics, growth, distribution, density, and age structure. Insects play a vital role in population ecology by influencing ecosystems and human societies. They contribute to ecological processes such as decomposition, pollination, and nutrient cycling. In addition, some insects produce valuable substances, and predatory insects help control pests. Understanding population dynamics and interactions is crucial for conserving and managing natural resources effectively. Population ecology is a branch of ecology that focuses on studying the lives of organisms within populations and their interactions with the environment and other populations. Different species have developed various strategies to deal with organisms of their species or other species. Some species compete directly with individuals of the same species, while others form social groups and cooperate to secure resources. Population ecologists examine complex interactions between organisms and their environment, which lead to different selective pressures for animals that compete with individuals of the same species. Humans, for example, have been successful in part because of their social nature and ability to cooperate to obtain vital resources. The field of population ecology seeks to answer questions about the carrying capacity of the environment, the optimal population size, the causes and mechanisms of population growth, and population distribution. Insects play a significant role in biodiversity, accounting for 64% of the world's biodiversity. They have diverse functional roles in ecosystems, including herbivores, hunting, parasitism, decomposition, and pollination. Various factors influence the number, population, and survival of insects, including insect diversity, abundance, evolution, and habitats. Population ecology studies these factors to understand the survival and current population dynamics of insects. The distribution of insects is an important indicator of species diversity and is influenced by factors such as time, conditions, and food resources. For example, the leopard beetle Cicindela longilabris is found at higher latitudes and elevations, with populations ranging from northwestern Canada to the coastal states of eastern Canada. Ecologists believe that historical climate changes, such as the last Ice Age, have influenced the current distribution of this species. In studying insect populations, ecologists use sampling techniques to estimate population size and abundance. Statistical methods, such as the rarefaction method, are employed to compare species abundance in different areas and estimate the number of species present in a sample. Understanding changes in insect population density over time is important, and ecologists study population life cycles and population explosions to gain insights into these fluctuations. By comprehending and predicting changes in insect populations, ecologists can mitigate potential damage and obtain valuable information about insect abundance. Certain species of locusts, including the desert locust, migratory locust, tree locust, and Australian locust, experience periodic population eruptions. In South America, various species of desert locusts are also significant pests. Climatic factors play a significant role in the formation and migration of locust swarms. Locust eggs can remain dormant in the soil until rain triggers their hatching. The rainy season is optimal for egg development, and rainfall also promotes the growth of green plants, which serve as food for nymphs and adult grasshoppers. The El Nino phenomenon, characterized by periodic changes in flight patterns, has a significant impact on locust populations, causing substantial damage every few years. Satellite imagery is commonly used to identify locust groups by detecting areas of new plant growth following rain. Once the nymphs have exhausted their food sources, the locust swarm enters the migratory phase, guided by wind direction. These swarms can persist for months or even years under favorable weather conditions, but population declines occur when dry weather or significant temperature drops occur. In conclusion, population explosions in migratory locusts are primarily influenced by density-independent factors like climate change, rather than density-dependent factors.