Spider mite in the context of Spider web

Haplodiploidy is a sex-determination system in which males develop from unfertilized eggs and are haploid, and females develop from fertilized eggs and are diploid. Haplodiploidy is sometimes called arrhenotoky.

Haplodiploidy determines the sex in all members of the insect orders Hymenoptera (bees, ants, and wasps) and Thysanoptera ('thrips'). The system also occurs sporadically in some spider mites, Hemiptera, Coleoptera (bark beetles), and rotifers.

The term carotene (also carotin, from the Latin carota, "carrot") is used for many related unsaturated hydrocarbon substances having the formula C₄₀H_x, which are synthesized by plants but in general cannot be made by animals (with the exception of some aphids and spider mites which acquired the synthesizing genes from fungi). Carotenes are photosynthetic pigments important for photosynthesis.

Carotenes contain no oxygen atoms. They absorb ultraviolet, violet, and blue light, and scatter orange or red light, and yellow light (in low concentrations).

Pesticide induced resurgence, often shortened to resurgence in pest management contexts, can be described as a constraint of pesticide use, by which they fail to control pests such as insects and spider mites: instead ‘flaring up’ populations that may have been of minor importance. Although there are more than one mechanisms by which this takes place, mortality of natural enemies following the use of broad-spectrum insecticides and acaricides is often implicated. This is sometimes called the “pesticide treadmill”: a term coined by Robert van den Bosch to describe a self-reinforcing over-dependence on agrochemicals and inimical to natural biological controls. Notable examples include the flare-up of rice brown planthopper populations, following over-use of broad-spectrum inscticides.

Ballooning, sometimes called kiting, is a process by which spiders, and some other small invertebrates, move through the air by releasing one or more gossamer threads to catch the wind, causing them to become airborne at the mercy of air currents and electric fields. A 2018 study concluded that electric fields provide enough force to lift spiders in the air, and possibly elicit ballooning behavior. This is primarily used by spiderlings to disperse; however, larger individuals have been observed doing so as well. The spider climbs to a high point and takes a stance with its abdomen to the sky, releasing fine silk threads from its spinneret until it becomes aloft. Journeys achieved vary from a few metres to hundreds of kilometres. Even atmospheric samples collected from balloons at five kilometres altitude and ships mid-ocean have reported spider landings. Ballooning can be dangerous (due to predators, and due to the unpredictable nature of long-distance ballooning, which may bring individuals to an unfavorable environment).

It is observed in many species of spiders, such as Erigone atra, Cyclosa turbinata, as well as in spider mites (Tetranychidae) and in 31 species of lepidoptera, distributed in 8 suborders. Bell and his colleagues put forward the hypothesis that ballooning first appeared in the Cretaceous. A 5-year-long research study in the 1920s–1930s revealed that 1 in every 17 invertebrates caught mid-air is a spider. Out of 28,739 specimens, 1,401 turned out to be spiders.

Micromachines are mechanical objects that are fabricated in the same general manner as integrated circuits. They are generally considered to be between 100 nanometres to 100 micrometres in size, although that is debatable. The applications of micromachines include accelerometers that detect when a car has hit an object and trigger an airbag. Complex systems of gears and levers are another application.