Reproductive and Developmental Biology of Acroclisoides sinicus, a Hyperparasitoid of Scelionid Parasitoids

Abstract

Acroclisoides sinicus (Hymenoptera: Pteromalidae) was described in 1988 from China, but recent findings in Europe and North America within the framework of Halyomorpha halys (Hemiptera: Pentatomidae) biological control indicate a Holarctic distribution. The few records and fragmented information on A. sinicus are derived from generic observations of other species belonging to the same genus, and its biological and ethological traits are still completely unexplored. It was suspected to be a facultative or obligate hyperparasitoid of many egg parasitoid species (e.g., Scelionidae and Eupelmidae), especially those parasitizing Pentatomidae eggs. Laboratory colonies of A. sinicus were established from specimens collected in the field in Europe and the USA, which allowed us to investigate for the first time the life traits of this somewhat enigmatic species. Our studies confirmed the obligate hyperparasitoid hypothesis for species of Scelionidae but not of Eupelmidae. Laboratory studies revealed that A. sinicus is extremely selective in its host recognition as only the pupal stage of its host species is exploited for parasitization. Taking into consideration its hyperparasitoid habit, the adventive A. sinicus populations in Europe and North America may potentially be severe threats to pentatomid natural control as new components in the trophic chain of pentatomids and their parasitoid guilds.

Hyperparasitism of Acroclisoides sinicus (Huang and Liao) (Hymenoptera: Pteromalidae) on Two Biological Control Agents of Halyomorpha halys

“…[ 28 ]. Recent findings confirmed what was previously supposed, that A. sinicus acts as an obligate hyperparasitoid of pupae of Scelionidae but not of Eupelmidae [ 29 ].…”

“…The results obtained in the second no-choice test confirm that A. sinicus is a hyperparasitoid of the pupal stage of Trissolcus sp. The differences among oviposition days can be explained by the host’s different developmental stages or ages [ 29 ]. No sign of hyperparasitism was observed in H. halys eggs that were parasitized by the primary parasitoid 2 days previously, since the Trissolcus pupae were probably not formed.…”

“…It seems that the 4th and 5th day from primary oviposition is the optimal period for oviposition of A. sinicus , since high levels of hyperparasitism efficiency were observed. This could be related to the fact that 4 days are needed for the development of Trissolcus pupae [ 29 ]. Additionally, data from the second no-choice experiment suggest that 6th and 7th day-old pupae are not optimal for A. sinicus development.…”

“…Nevertheless, it should be noted that the number of observed eggs in each period reflects the effective maximum egg load of an A. sinicus female. Egg production of A. sinicus females may be stimulated by the presence of the male and the presence of the empty natal egg mass in which traces of the host are present [ 37 ], and this could explain the fact that the number of eggs was higher here than compared to Giovannini et al [ 29 ], where A. sinicus egg load was studied on isolated females.…”

Preempting the Arrival of the Brown Marmorated Stink Bug, Halyomorpha halys: Biological Control Options for Australia

“…(Hymenoptera: Pteromalidae) and Ooencyrtus sp. (Hymenoptera: Encyrtidae) were found in several studies [ 1 , 16 , 25 , 30 ], but these are most likely hyperparasitoid species, as found in other studies [ 16 , 31 , 32 , 33 ], although not all Ooencyrtus sp. are hyperparasitoids [ 34 ].…”