Mealworm

Mealworms are the larval form of the yellow mealworm beetle, Tenebrio molitor, a species of darkling beetle. Like all holometabolic insects, they go through four life stages: egg, larva, pupa, and adult. Larvae typically measure about or more, whereas adults are generally in length. The mealworm beetle breeds prolifically. Males insert sperm packets with their aedeagus. Within a few days the female burrows into soft ground and lays eggs. Over her adult lifespan of about 6-12 months, a female will, on average, lay about 500 eggs. After 4 to 19 days the eggs hatch. During the larval stage, the mealworms feed on vegetation and dead insects and molt between each larval stage, or instar (9 to 20 instars). After the final molt, they pupate. The new pupa is whitish and turns brown over time. After 3 to 30 days, depending on environmental conditions such as temperature, it emerges as an adult beetle. A sex pheromone released by male mealworms has been identified. Inbreeding reduces the attractiveness of sexual pheromone signaling by male mealworms. Females are more attracted to the odors produced by outbred males than the odors produced by inbred males. The reduction of male signaling capability may be due to increased expression of homozygous deleterious recessive alleles caused by inbreeding. Tenebrio molitor is often used for biological research. Its relatively large size, ease of rearing and handling, and status as a non-model organism make it useful in proof of concept studies in the fields of basic biology, biochemistry, evolution, immunology and physiology. Mealworms have generally been considered pests, because they feed on stored grains. Mealworms probably originated in the Mediterranean region, but are now present in many areas of the world as a result of human trade and colonization. The oldest archaeological records of mealworms can be traced to Bronze Age Turkey. Records from the British Isles and northern Europe are from a later date, and mealworms are conspicuously absent from archaeological finds from ancient Egypt.