IsAnastrepha obliqua(Diptera: Tephritidae) a natural host of the Neotropical parasitoidsDoryctobracon crawfordiandOpius hirtus?

Abstract

An understanding of the search, selection and host use behaviours of parasitoids that have the potential to be used as biological control agents is becoming increasingly important. We studied under laboratory conditions the host suitability of Anastrepha obliqua (Macquart) and Anastrepha ludens (Loew) larvae for the parasitoids Doryctobracon crawfordi (Viereck) and Opius hirtus (Fischer), which are native to the Americas. By counting the oviposition scars on the puparium, we found that both types of larvae were equally attacked; however, the pupa dissections revealed that different numbers of eggs were laid in each type of larvae. The A. obliqua larvae were significantly less parasitised than those of A. ludens, and immature insect development or adult emergence was not in either parasitoid species. Dissections of the parasitised A. obliqua pupae also showed that the immature parasitoids of both species died by encapsulation and melanisation, and there was a high proportion of unemerged adult flies. By contrast, A. ludens parasitised pupae contained several viable immature parasitoids that subsequently emerged as adult parasitoids. These results indicated contrasting suitability conditions of A. ludens and A. obliqua larvae as hosts of O. hirtus and D. crawfordi parasitoids, which suggest that A. obliqua is not a natural host for either parasitoid species. These findings will improve the understanding for the use of these parasitoid species in projects for biological control against economically important fruit flies of the genus Anastrepha.

Best Host Age of Anastrepha obliqua (Diptera: Tephritidae) for Multiplication of Four Native Parasitoids from the Americas

“…The ectoparasitic nature of the genus Dirhinus may account for the lower requirement for a more specific age range for parasitism ( Dressner 1954 , Sivinski et al 1998 ). Although A. obliqua can be considered as a low suitable host for Dirhinus , there is also evidence that A. obliqua exerts a high level of antagonism for the immature parasitoid development of other species ( Silva et al 2002 , Poncio et al 2015 ). Higher percent of Dirhinus parasitism (>30%) have been obtained with A. ludens as host ( Cancino et al 2009a , b ).…”

Host-specific demography of Utetes anastrephae (Hymenoptera, Braconidae), a native parasitoid of Anastrepha spp. fruit flies (Diptera, Tephritidae)

“…Regarding the immune response of A. obliqua to parasitoids, it has been reported that its larva possesses 5-6 types of haemocytes that generate a strong immune response (phagocytosis and production of reactive oxygen species) (Silva et al 2002;Gómez-Alonso et al 2022). The presence of these haemocytes resulted in the melanization and encapsulation of the first immature stages of parasitoids (Silva et al 2002;), which has not been observed in A. ludens (Poncio et al 2016; 2020). This high immunity response of A. obliqua larva represents an important factor in increasing parasitoid mortality during development.…”

“…The higher reproductive rates found when A. ludens larvae were the host, compared to A. obliqua, can be attributed to three factors: 1) the effect of host switch, 2) the quality of the host, and/or 3) the immunological response. It is known that host switching may adversely affect the fitness of parasitoid species during the very first generations in a new host, although in subsequent generations their performance can improve (Zenil et al 2004;Jones et al 2015;Poncio et al 2016). When the parasitoid D. longicaudata was previously maintained on A. fraterculus larvae, the adults parasitized more on this host than when Ceratitis capitata larvae (Wiedemann, 1824) were offered as an alternative host (Ovruski et al 2011;Rohr et al 2019).…”

Irradiation and parasitism affect the ability of larval hemocytes of Anastrepha obliqua for phagocytosis and the production of reactive oxygen species

“…This discrepancy could be explained by the different origins of the larvae used; while they worked with wild larvae, our data were obtained from a laboratory strain. Nevertheless, the nondevelopment of D. crawfordi and other sympatric parasitoids in A. obliqua larvae is clear evidence of their high capacity for immunological reactions (Poncio et al, 2015).…”

“…However, it is also necessary to use radiation doses higher than 40 Gy for those parasitoid species that are naturally unable to develop successfully inside larvae of some Anastrepha species (Cancino et al, 2012). This occurs with the Neotropical‐native parasitoid Doryctobracon crawfordi (Viereck) (Hymenoptera: Braconidae), which has been recorded as nonviable in nature on Anastrepha obliqua (MacQuart) (Diptera: Tephritidae) larvae (Poncio et al, 2015). Doryctobracon crawfordi is a larval parasitoid that has coevolved in sympatry with Anastrepha ludens (Loew), in which it successfully develops.…”