DistributionThe large white is common throughout Europe, north Africa, and Asia to the Himalayas often in agricultural areas, meadows and parkland. It has managed to establish a population in South Africa and in 1995 it was predicted to spread to Australia and New Zealand.
The large white is a strong flier and the British population is reinforced in most years by migrations from the continent. Scattered reports of the large white from the northeastern United States over the past century are of a dubious nature and indicate either accidental transport or intentional release. Such introductions threaten to establish this agricultural pest in North America.
In 2010 the butterfly was found in Nelson, New Zealand where it is known as the great white butterfly. It is classed as an unwanted pest due to the potential effect on crops. For a limited period in October 2013 the Department of Conservation offered a monetary reward for the capture of the butterfly. After two weeks, the public had captured 134 butterflies, netting $10 for each one handed in.
BehaviorMales do not display considerable amounts of territorial behavior. It has been suggested that this could be a reason why there is no observed significant sexual dimorphism between the male and female large white butterflies.
ReproductionThe large white eggs appear as a pale yellow color. They turn into a darker yellow within twenty-four hours of being oviposited. A few hours prior to hatching, they will become black in color, and the shell will become more transparent, and the larvae will appear visible.Large white larvae experience four moltings and five instars. The first instar follows hatching of the egg into large white larvae. The larvae are a light yellow in color with distinctive brown heads and have soft bodies. The larvae appear as if they are very hairy. Following a molting, the larvae enter the second instar. They have tubercles covered with black hair. In the third instar, large white larvae display more activity. This instar is when the larvae are observed to eat voraciously, and cause significant amounts of damage to their host plant. At this point, they are observed to be more yellow in color, studded with black dots. Following the third instar, the larvae go through the fourth instar, with similar appearances as the larvae of the third instar, but with more aggrandized size and feeding behavior. The large white larvae are observed to be cylindrical, robust, and elongated by the fifth instar, yellow in color and with bright coloration on their abdomen and thorax. They are also observed to have a gray and black head. This instar requires maximum food quality and quantity in order to aid in full development, otherwise the larvae dies before becoming an adult butterfly.
Large white larvae are continuously growing in size with each molting and instar.The large white eggs hatch approximately one week after being laid and live as a group for some time. The hatching period constitutes around two to seven hours. Upon hatching, they cause a lot of damage to the host plant by eating away at and destroying the host plant.
FoodLarge white butterflies have a preference for what types of food plant they usually eat. Studies have shown that the preference for certain plants is reliant upon the butterflies’ previous experiences. The large white butterflies, then, are shown to rely on the species of food plants, the time of experience, and the choice-situation. Thus, the large white butterflies learn what types of foods they prefer, rather than relying on their sense organs or physiological changes. In contrast, this preference for adult foodplant differs from the preference of female large whites using visual cues such as plant color to determine the best host plants for oviposition.
Plants with mustard-oil glucosides are important for this butterfly because it dictates their eating behaviors, and resultant survival rates, as specified in the section regarding oviposition. This is so beneficial for large whites because their large consumption of plants containing mustard oils is the specific reason they are so distasteful to predators, such as birds. Thus, caterpillars are protected from attack, despite them being brightly colored; in fact, the bright coloration is to signal to predators that they taste bad.
However, there is more benefit to this species’ use of mustard oil glucosides. In addition to predator protection, these glucosides belong to a class of stimuli that produce the biting responses associated with eating. Some plants contain alkaloids and steroids; these reduce and inhibit the butterflies’ responsiveness to mustard oil glucosides. Thus, this utilization of mustard oil glucosides dramatically affects the behavior of the butterfly, and the resulting food selection for survival.
PredatorsLarge white butterflies do not have a specific group of predators. Instead, they are preyed upon by a wide range of animals, and even the occasional plant. This butterfly’s main predators include certain species of birds; however, large whites can also be preyed upon by species in orders such as hymenoptera, hemiptera, coleopteran, diptera, arachnids; some species of mammals, one of reptilia, one species of insectivorous plant, and species in amphibian orders, as well as other miscellaneous insect species. The butterflies are typically preyed upon as eggs, larvae, and imagines.
MigrationThe large whites are found throughout most of Eurasia, though there are some seasonal fluctuations present due to migration. The northern populations tend to be augmented during the summer migration season from butterflies from southern areas. The large whites fly starting early spring, and keep migrating until seasons shift to autumn and the resultant cold weather. This means the large whites typically take two to three flights per butterfly reproductive season.
Large white butterfly migration patterns are typically observed only when there is a disturbance. In general, the large white butterfly’s migratory patterns are atypical; normally, butterflies fly towards the poles in the spring, and towards the more temperate Equator during the fall. However, they fly in random directions, excluding North, in the spring, and there is little return migration observed. However, it has been hard to track entire migratory paths, since these butterflies can migrate more than 800 kilometers; thus, individual butterflies may not migrate the 800 kilometers, but rather that other butterflies start their migrations from where the other butterflies ended.
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