Parasitoid is an organism that attacks any developmental stage of its host, characterized by its larvae which grow on or inside the host and always kill it as part of its life cycle (Godfray and Shimada 1999, Machkour-M’Rabet et al. 2015).
M. scalaris (Loew, 1866) is a cosmopolitan small synanthropic fly (1–6 mm) in the family Phoridae of the order Diptera. Members of this family are commonly known as “scuttle flies” because adults erratically move in rapid bursts with short pauses (Costa et al. 2007). They are also known as “humpbacked flies” due to their humpbacked appearance, and “coffin flies” because adult females are known to dig down two meters deep in order to reach buried corpses and penetrate closed containers such as coffins to lay their eggs (Varney and Noor 2010).
M. scalaris is an omnivorous species, capable of exploring a large variety of environments and ecological niches. It is known as an important detritivore species with larvae (maggots) feeding on a variety of food of both animal and plant origin, and acting as saprophagous, feeding on nourishment from decaying organic matter, sarcophagous, consuming flesh and necrophagous, feeding on corpses or carrion. However, protein food sources are preferred by the females for maturation of their eggs. These feeding habits make this species a facultative predator, parasite, and parasitoid on/in other invertebrates under natural and laboratory conditions (Sukontason et al. 2003, Costa et al. 2007, Disney 2008).
M. scalaris was reported as a parasitoid of some insect species of agronomic and medical importance, including members of the following orders: Hemiptera (Costa et al. 2007), Orthoptera (De Gregorio and Leonide 1980, Quesada-Béjar et al. 2017), Mantodea (Koch et al. 2013), Lepidoptera (Ulloa and Hernandez 1981, Souza et al. 2020), Diptera (Batista-Da-Silva 2012, Marchiori 2018), and Coleoptera (Harrison and Gardner 1991, Arredondo-Bernal and Trujillo-Arriaga 1994).
Some cases of animal myiasis caused by M. scalaris in a rattlesnake were reported in Brazil (Silva et al. 1999), and infestation of frog eggs was reported in Panama (Brown and Horan 2012). Furthermore, facultative and accidental myiases by M. scalaris in nasopharyngeal, intestinal, and leg wound were reported in hospitalized patients in Kuwait and Egypt were recorded (Hira et al. 2004, Mazayad and Rifaat 2005).
The egg of M. scalaris is small and boat-shaped. It is characterized by its gunwale-like palisade of flat platelets that surround the respiratory plastron with its scattered tubercles. Eggshells are more resistant towards unfavorable factors such as bacteria attack and dryness (Wolf and Liu 1996, Disney 2008). The larva (maggot) of M. scalaris is almost creamy white and undergoes two molts leading to three larval instars. The first and second larval instars measure 0.75–2 mm in length, cylindrical, narrowed toward the head, with two cephalic lobes are found on cephalic region and six sensory papillae positioned tangential to the antenna (Boonchu et al. 2004). The third larval instar is similar to the first and second ones. However, it is usually more than 2 mm in length with spiracular hairs appearing centrally at the constriction of the slender spiracular plates (Sukontason et al. 2002), and this instar can be subdivided into two stages, feeding stage and post-feeding stage (Greenberg, 1991). Pupa of M. scalaris is dorsoventrally flattened with an invaginated cephalic segment, with a pair of long and slender pupal respiratory horns at the end of the fifth dorsal segment. Several spiral papillae are arranged on the respiratory surface of these horns. The papillae are oval and domed-shaped with a single longitudinal straight aperture on them. There is an invaginated cephalic segment with a pair of antennae at the ventral part. A pair of round anterior spiracles is found dorsolateral on the prothorax (Sukontason et al. 2005). The adult M. scalaris is small (1–6 mm in length) with a humpbacked appearance, it can be distinguished by the following characters: Frons brownish-yellow, with dense fine microsetae; scutum brown dorsally; scutellum pale brownish-yellow, with two pair of bristles; costa extends more than half wing length, vein R2 + 3 present; legs long, yellowish in color; mid-tibia without paired bristles; hind tibia without differentiated antero-dorsal hairs, with a dorsal hair palisade; hind femur with a brown tip; abdominal tergites dark brown with yellowish markings; palps straw yellow; tip of anal tube with feathered bristles (Alam et al. 2016, Zhang et al. 2017).
M. scalaris was recorded from Egypt (Steyskal and El-Bialy 1967). Abdel-Gawad (2018) and Ismail (2018) reared it in Ain Shams University, Cairo, Egypt, for morphological studies. However, no extensive taxonomic or faunistic studies have been carried out to indicate the exact distribution of this species or its relative phorid species in Egypt.
The southern green stink bug, Nezara viridula (Linnaeus, 1758) (order Hemiptera: family Pentatomidae), is a cosmopolitan bug species distributed throughout the tropical and sub-tropical regions of Africa, America, Asia, and Europe. This bug is considered as one of the most important damaging pests all over the world. It is a highly polyphagous insect, attacking a wide range of grain, fruit, and vegetable crops including beans, cabbage, citrus, cotton, nuts, rice, sugarcane, and wheat, with a preference for leguminous plants. Adults and nymphs of N. viridula feed on plant fluids by piercing plant tissues with their piercing-sucking mouthparts. Adults cause maximum damage attacking all parts of plant including stem, petioles, foliage, flowers, fruits, and seeds. Feeding on flower buds causes premature abscission, and damage to seed pods (Hoffman 1935, Corpuz 1969, Hussain and Saharia 1994, Sudan 2008, Tara and Sharma 2010).
In Egypt, heavy infestations and damaging outbreaks of N. viridula were reported on citrus in some Egyptian governorates including Menofieh, Gharbieh, and Sharkieh in October 1973, the infestation was observed also on some adjacent crops as maize, vegetables (especially cabbage) and sesame (Attiah et al. 1974, Ali et al. 1978). According to El Maghrabi (1998) and our observations, this bug is distributed in all Egyptian ecological zones: coastal strip, lower Nile Valley and Delta, Fayoum, Western Desert, Eastern Desert, upper Nile Valley, Sinai, and Gebel Elba. It was detected throughout the year attacking fruits and major field crops including rice (Oryza sativa L.), sugar cane (Saccharum officinarum L.), wheat (Triticum aestivum L.), corn (Zea mays L.), cotton (Gossypium barbadense L.), alfalfa (Medicago sativa L.), clover (Trifolium alexandrinum L.), sesame (Sesamum indicum), okra (Abelmoschus esculentus (L.)), potato (Solanum tuberosum L.), tomato (Solanum lycopersicum L.), faba bean (Vicia faba L.), mango (Mangifera indica L.), and citrus (Citrus spp.).
