Indianmeal moth

Plodia interpunctella is found on every continent in tropical habitats, excluding Antarctica. Within the United States, the moth is most commonly found in Florida, where it thrives in the tropical habitat. == Taxonomy and etymology ==

The Indian-meal moth is the only known living species of the genus Plodia. It is closely related to the genera Cadra and Ephestia, which include other pest species like E. kuehniella, also known as the "flour moth". The species has been described under a number of junior synonyms, which may occasionally still be found in non-entomological sources. == Description ==

Adults are in length with wingspans. The distal two thirds of their forewings are generally reddish brown in color with a copper luster. They can also be bronze or dark gray. The more proximal parts of the wings are yellow-gray or white-gray, with a dark band at the intersection between the proximal and distal regions. The hindwings, in general, are uniformly gray. The eggs of the Indian-meal moth are white, ovate, and very small. It is difficult to see them with the naked eye. Newly hatched larvae are equally difficult to see. They are mostly off-white in color, have brown heads, and develop through five to seven larval instars. When these larvae mature, they measure about long. Larvae also have three sets of legs near the head and five sets of prolegs protruding from the abdomen. The legs help the larvae move over long distances in order to find pupation sites. ==Food resources==

Indian-meal moths feed on plants, grains, and other human food products. Plant-based foods Moths feed on many plant-based foods including dry pet food (plant based), birdseed, cereal, soup mixes, bread, pasta, rice, flour, spices, dried fruits and nuts. There is strong evidence that the northern Manitoba wheat supports the development of the moth. Other optimal diets include sultanas, American yellow corn and almonds. Groundnuts and maize meal, on the other hand, result in a longer development time for the moths. Non-plant foods Indian-meal moths are also known to cannibalize larvae. This often leads to viral granulosis infections spreading through an Indian-meal moth population. Healthy larvae are picked more often than unhealthy larvae for cannibalism. There appears to be no kin discrimination and siblings can be eaten by caterpillars. Foraging flights Though Indian-meal moths generally do not migrate over long distances, they do engage in long-distance foraging flights. These flights take place during the twilight hours during which blue light (400–475 nm) rather than UV light (10–400 nm) is dominant and attracts the moths. Blue light's role in the Indian-meal moth foraging behavior has recently been harnessed as a form of pest control since it is attractive to the moth. == Life history ==

Eggs Usually the life cycle of an Indian-meal moth colony starts in a location where grain is present. The temperature within a grain bin must exceed . The eggs of the moth are grayish white and have a length between . Eggs can be laid directly on the food source singly or in groups of between 12 and 30. A mature female may lay between 100 and 300 eggs at a time. Diapause Diapause is defined as a delay in animal development due to certain external factors and can end once the adverse environmental conditions wear off. The duration of diapause can vary in Indian-meal moths. Diapause is especially prevalent late in the breeding season. During the egg stage, if the temperature of the moth's environment exceeds , it can cause a delay in hatching. In the moth's early larval stage, temperatures of below can cause a similar diapause. Different strains of P. interpunctella have differing tendencies to enter diapause. Image:Mating_plodia_big.jpg|Mating adults Image:Plodia.interpunctella.eggs.jpg|Freshly laid eggs Image:Plodia interpunctella lrv 79.jpg|Larva on sprinkles Image:Plodia_interpunctella_pup_25.jpg|Empty pupal case ==Enemies==

Predators • Nocturnal insectivores: birds, bats, and owls • Lizards (Lacertilia) • Rodents (Rodentia) • Spiders (Arachnida) • Other cannibalistic Indian-meal moths Diseases • Baculoviruses are double-stranded DNA viruses commonly used as biological control agents for the Indian-meal moth and are considered parasites. They come from a family of viruses that are limited to insects as hosts. Baculovirus isolates have been often isolated from other Lepidoptera. At sub-lethal dosages, baculoviruses decrease reproductive capacity in terms of egg viability and production. Immunity Indian-meal moths are developing a resistance to many kinds of biological agents, such as the granulosis virus. Use of pest-control agents can cause resistance to these agents to be selected for in populations of Indian-meal moths. In populations exposed to the granulosis virus, it was found that the moths were 96 times more resistant to the virus; this led to the prohibition of many such biological agents. Regulations prevent the use of many pesticides near food sources, so these pests are highly suitable for control with natural predators. ==Mating==

Male–male interactions Sperm competition Females mate multiple times, so sperm competition could be an important aspect of male–male competition for being reproductively successful. Males have a limited number of sperm and allocate it depending on various factors. Male Indian-meal moths ejaculate a greater amount of sperm to females that have mated multiple times previously. This is to ensure a greater chance of success in sperm competition in the females' storage organs. Males also ejaculate more sperm when mating with a younger female. Food and pupation site competition The most common type of competition in Indian-meal moths is due to a lack of food. This competition can change the timing of male and female emergence, reducing the chance of early males finding females to mate with, which could encourage emigration. This is considered a form of male–male competition because males that emerge at an appropriate time are more likely to be reproductively successful with the surrounding females. Males are also involved in finding pupation sites. If the larvae do not find pupation sites in the food layer, they may wander long distances to find one. This competition to find a pupation site affects males more than it does females, it indirectly impacts females as well because it results in a delayed population of males to mate with. Male pheromones Male moths also release pheromones. After approaching the female from the back, the male releases a pheromone from wing glands located at the base of each forewing. These pheromones induce the female to remain stationary in the acceptance posture (raised abdomen between wings) which facilitates copulation. Copulation and multiple mating Indian-meal moths are known to mate multiple times. For males, it is vital to ensure paternity after copulation. To ensure this trait, males who mate with a female first (before any other males) will insert a large package of spermatophore, accessory gland fluids, and nutrients into the bursa copulatrix of the female during copulation. Other donations after the first mating are smaller in size. Even so, there is no change in postcopulatory behavior in females after this large donation (with respect to pheromone production and calling behavior). Changes in fecundity It has been observed in many insects that vital resources are tracked using odor plumes. For the Indian-meal moth these odors have other effects as well. The Indian-meal moth's fecundity and fertility was found to be enhanced in the presence of the odor of vital nutrients. This effect is thought to be genetic since it is not related to parental generations or previous experiences in the lifetime of the moth. Females also show a strong preference towards laying their eggs near the site of the odor. It was observed that without antennae, this effect is lost, suggesting that there are olfactory receptors in the antennae. Interspecific courting The Indian-meal moth often takes part in interspecific courtship especially with the almond moth (Cadra cautella). Successful mating between the species does not happen due to multiple isolation mechanisms. The main mechanism that has been identified is the male sex pheromone. This pheromone is a strong species recognition signal. It allows the almond moth to differentiate between members of its own species and members of the Indian-meal moth species. There are also mechanical barriers to insemination that render the species incompatible. Their courtship behaviors are also relatively incompatible. Thus, copulation rarely occurs. Even when courtship does continue to a later stage, the female of the other species rejects the male due to the wrong pheromone being released at the wrong time from scent scales. Even with these fail safes, some male almond moths are still excited by Indian-meal moth females. They may be able to successfully copulate, but insemination is not possible. == Pest status and pest control ==

s Status Indian-meal moth larvae can infest a wide range of dry foodstuffs of vegetable origin, such as cereal, bread, pasta, rice, couscous, flour, spices, dried fruits, and nuts. More unusual recorded foods include crushed red pepper, chocolate and cocoa beans, coffee substitute, cookies, dried mangelwurzel, and even the toxic seeds of jimsonweed (Datura stramonium). They have also been known to infest commercial pet food, such as cracked corn used for bird feed. They often leave webbing in the food they infest. Control After larvae or moths have been found, it is important to throw out all food sources not in very tightly sealed containers. Moth larvae can chew through plastic bags and thin cardboard, so even unopened packages may become infested. They are also notoriously difficult to get rid of, and can crawl on ceilings and spin cocoons in rooms other than where they hatched. Last instar larvae are able to travel significant distances before they pupate. When seeking the source of an infestation, the search thus cannot be limited to the immediate area where pupae are discovered. Nontoxic traps are available to monitor outbreaks. One type of trap is a triangular box with a pheromone lure and sticky walls inside. These traps are known as pheromone traps. Male moths are attracted by the female pheromone (the lure) and stick against the sticky walls inside the box. The efficiency of traps is doubtful as they only capture males, and usually only a fraction of them, while adult females, eggs and larvae are unaffected, enabling a possible reinfestation. It is most effective to treat the infestation by eliminating the source and any affected food items, interrupting their mating processes, and repelling them from the areas where dried food and grains are kept. It is recommended to first eliminate the source of infestation followed by larvae, eggs, and eventually moths. The caterpillars are parasitized by Habrobracon hebetor, a braconid wasp which is a potential biological control agent. Additionally, blue to violet light can be very effective in drawing moths out, which suggests that the deployment of violet light could become another pest control tactic for these moths. == References ==