Presence and infestation rate of Senotainia tricuspis (Meigen) (Diptera, Sarcophagidae) on honey bees in the Mediterranean Region

Flies are well known to be endoparasitoids of bees, such Conopidae to bumble bees and leaf-cutter bees, Antrax antrax to several Osmia and other Megachilide species and Senotainia tricuspis (Meigen) to honey bees (Felicioli, Franceschini, & Pinzauti, 2000 Felicioli, A., Franceschini, S., & Pinzauti, M. (2000, 20–26 August). The agony of a honey bee colony parasitized by the Sarcophagid fly Senotainia tricuspis: Temperature and humidity variations. In Proceedings of the XXI International Congress of Entomology, Foz de Iguassù, Brasil. vol. 1, p. 244. ; Morse & Flottum, 1997 Morse, R. A., & Flottum, K. (1997). Honey bee pests, predators and diseases (3rd ed.). Medina, OH: The A.I. Root Compan S. tricuspis with a length of 5–8 mm and gray-black color is similar to a domestic fly. Morphologically, it is characterized by a light strip between the reddish compound eyes (Bedini, Pinzauti, & Felicioli, 2006 Bedini, G., Pinzauti, M., & Felicioli, A. (2006, 25–27th April). Interaction between Apis mellifera and its parasites Senotainia tricuspis and Varroa destructor: A teoric model. International Apicultural Scientific Conference, Pulawy, Poland. ). Females of S. tricuspis are larviparous and attack forager honey bees flying in front of the hive. When S. tricuspis reaches its host, it deposits a first instar larva on the thorax of the honey bee. Then the larva enters the body of the honey bee and develops, feeding on hemolymph and wing muscles, until it kills its host in 2–4 days (Bedini, Pinzauti, & Felicioli, 2006 Bedini, G., Pinzauti, M., & Felicioli, A. (2006, 25–27th April). Interaction between Apis mellifera and its parasites Senotainia tricuspis and Varroa destructor: A teoric model. International Apicultural Scientific Conference, Pulawy, Poland. ). At the third instar, the last larval stadium, the larva exits from the body of the dead host. Sometimes, it can also feed on the body of the dead host as a scavenger. Then the larva enters the soil for pupation, with different depths according the structure of the soil: deeper in clay and shallower in sandy soil. During the late spring or summer, the adult fly emerges 7–12 days after pupation and the new generation can go forward with its own parasitic behavior. Those larvae that pupate in late summer or autumn will undergo diapause until next spring when the adults emerge (Bailey & Ball, 1991 Bailey, L., & Ball, B. V. (1991). Honey bee pathology (2nd ed.). London: Academic Press. [CrossRef] ). Attacks can be repeated every 10 s during the sunniest hours of the day. Each female has 600–700 larvae in its uterus and thus has the potential to kill hundreds of honey bee (Bedini, Pinzauti, & Felicioli, 2006 Bedini, G., Pinzauti, M., & Felicioli, A. (2006, 25–27th April). Interaction between Apis mellifera and its parasites Senotainia tricuspis and Varroa destructor: A teoric model. International Apicultural Scientific Conference, Pulawy, Poland. ). The aim of this work was to confirm the existence of S. tricuspis and to estimate its infestation rate and potential danger in apiaries in Arab countries of North Africa and the Middle East. Samples from Italy were used as a reference indicator for the level of infestation. For the monitoring of S. tricuspis, 124 samples were collected from seven countries: Algeria (33), Egypt (12), Italy (4), Iraq (18), Jordan (27), Palestine (9), and Lebanon (21). A pooled sample was collected from each apiary from three randomly chosen hives. Each sample represented one apiary and contained at least 50 forager bees. Hives were selected according to the beekeepers complaints of unexplained colony depopulation. Each apiary was been geolocalized using GPS, and its coordinates were used to produce a synoptic map of the pest distribution (Figure 1). The bees were kept in a closed glass jar of 390 ml volume. The jar was closed with a net to allow air exchange for the breathing of the bees. Then, the collected honey bees were observed for 72 h and eventual specimens of S. tricuspis larvae were counted and removed. Removal of S. tricuspis larvae is necessary to avoid the behavior of cannibalism, which is known with S. tricuspis larvae (Pinzauti & Santini, 1995 Pinzauti, M., & Santini, L. (1995). On the “apymiasis” caused by Senotainia tricuspis (Meigen) (Diptera, Sarcophagidae) in central Italy. In Proceedings of XXXIVth International Apicultural Congress, Lousanne, Switzerland. (Reprinted from L’Apicoltore Moderno, 86, 179–183). ). The % infestation of each bee sample was then calculated according to the formula: (number of S. tricuspis larvae emerged/number of collected bees) × 100. (Pinzauti & Santini, 1995 Pinzauti, M., & Santini, L. (1995). On the “apymiasis” caused by Senotainia tricuspis (Meigen) (Diptera, Sarcophagidae) in central Italy. In Proceedings of XXXIVth International Apicultural Congress, Lousanne, Switzerland. (Reprinted from L’Apicoltore Moderno, 86, 179–183). ), while the infestation rate among samples was calculated according to the formula: (number positive samples × 100)/total number of samples.