The black soldier fly or Hermetia illucens (Linnaeus, 1758) (Diptera: stratiomyidae) is one of the best-known flies all around the world for its nutritional value. This species is originally a new world species and was described in 1758 by the Swedish naturalist Carl von Linne, from South America, but transportation of food and fruits has caused this species to establish itself worldwide (Üstüner et al., 2003). It is an adaptable saprophagous species with larvae scavenging in various decayed organic matter of fruits, vegetables, and accumulated remains of vegetation, compost, manure, and carrion (Barragan-Fonseca et al., 2017). Black soldier fly larvae have the potential to turn organic waste into abundant fertilizers, besides being an excellent source of oil and protein for animal feed (Diclaro II & Kaufman, 2009). The nutritional values of Hermetia illucens make it the first choice for poultry, aquaculture, and livestock compound diets. Its simple mass-rearing cycle and added value to poultry manure, swine manure, as well as recycling the vegetable and fruit waste, turning bio-waste into a high-quality nutrient source for animal feed are other suitable benefits of this species, making it an important decomposer (Barragan-Fonseca et al., 2017; Bruno, 2018; Joly & Nikiema, 2019; Maquart, 2019).
Eggs
As with most other flies, eggs are milky white, laid by the female fly, and piled in groups resembling white rice grains in clusters (Barros et al., 2019; Sarwar, 2020). They lay their eggs in moist, decaying organic material such as fruits and manure (Fig. 1) (Amrul et al., 2022; da Silva & Hesselberg, 2020; Dzepe et al., 2020).
Larvae
Larvae are large saprophagous maggots with six larval instars and reach 25-30 mm in length and 6-8 mm in width in the last stages (Fig. 2). They are apodal, hemichephalic and holopneustic. The head capsule is a telescopic structure which is strongly sclerotized. The body has 12 segments and is densely covered with hairs and cilia, which often grow longer and thicker caudally; almost every segment has one pair of spiracles laterally (Barros et al., 2019; Oliveira et al., 2016).
Adults
Adults of Hermetia illucens are black at all body parts except the first abdominal segment, which is translucent, and the feet-like tarsi, which are white. The adults resemble wasps; the first segment of the abdomen is translucent and makes the fly mimic the wasp's waist. Eyes are widely separated in all sexes; the antenna has 8 segments with a last elongated flagellum twice as long as the head. Unlike other flies, there is no sexual dimorphism, but the genitalia are different, and females are larger than males. Mouthparts are reduced in Hermetia illucens, so they do not feed except for water. The main purpose after emergence is to mate and lay eggs and the Hermetia illucens adults cannot feed, and they lay their eggs just at near the decomposing material so they cannot be a medically important fly and transmit microorganisms to a human being (Fig. 3)(Bruno et al., 2019; Jeong et al., 2018; Oliveira et al., 2016).
World Distribution
There are several reports of h. illucens all around the world. It is reportedly native to the neotropics and has been reported from North America, Canada, and the United States to Central America and almost all parts of South America. It is believed that h. illucens might have been first introduced to Europe approximately 500 years ago, but the first record is from Southern Europe (Malta) in 1926 (Lindner 1936); nevertheless, now it has been reported from all around Europe, Asia, Africa, Americas, and Oceania.
Nearctic: USA (Alabama, Arizona, Arkansas, California, Connecticut, Delaware, District of Columbia, Florida, Georgia, Indiana, Iowa, Kansas, Louisiana, Maryland, Massachusetts, Mississippi, Missouri, New Hampshire, New Jersey, North Carolina, Pennsylvania, South Carolina, Texas and Virginia).
Neotropical: Argentina, Belize, Brazil, British Virgin Islands, Chile, Colombia, Costa Rica, Ecuador, Dominica, Dominican Republic, El Salvador, Grenada, Guatemala, Guyana, Haiti, Honduras, Jamaica, Mexico (Chiapas, Chihuahua, Jalisco, Nuevo León, Oaxaca, Quintana Roo, San Luis Potosí, Sinaloa, Tamaulipas, Veracruz, Yucatán), Panama, Paraguay, Peru, Puerto Rico, Suriname, Trinidad and Venezuela and Uruguay.
Palearctic: Albania, Canary Islands, Croatia, France, Italy, Japan, Malta, Spain, Switzerland and Yugoslavia.
Afro tropical: La Réunion Island, Liberia, Burundi, Rwanda, Uganda, Ethiopia, Senegal Cameroun, Congo, Ghana, Ivory Coast, Kenya, Madagascar, Mali, Namibia, South Africa, Tanzania, Zaire and Zambia.
Oriental: India, Indonesia (Java, Sulawesi), Japan (Ryukyu Islands), Malaysia, Nepal, Philippines, Sri Lanka, Taiwan, Thailand and Vietnam.
Australian: Australia (Queensland, Western Australia), Belau, Bonin Islands, French Polynesia (Austral Islands, Society Islands), Guam, Hawaiian Islands, Indonesia (Irian Jaya), Kiribati (Gilbert Islands), Marshall Islands, Micronesia, New Caledonia, New Zealand, Northern Marianas, Papua New Guinea (Bougainville Island, Papua New Guinea), Solomon Islands, Vanuatu, Western Samoa (DEMETRIOU et al., 2022; Gladun, 2019; MAQUART et al., 2020; Üstüner et al., 2003; Woodley & Thompson, 2001).
The aim of the current study was to collect the eggs and larval stages of flies from fruit waste decomposing in the field of Zanjan provinces, northwest Iran.