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Trichogramma leucaniae is believed to be an efficient biological control agent for controlling the soybean pod borer [SPB; Leguminivora glycinivorella]. The large eggs of Chinese oak silkworm, Antheraea pernyi, are one of the best alternative host for mass production of Trichogramma. However, they are considered poor host for the growth and development of T. leucaniae. Here, we determine the feasibility of successive rearings of T. leucaniae on the large eggs for eight generations and evaluated their capacity of parasitizing SPB eggs of different ages. In the first four generations, the suitability of T. leucaniae reared on large eggs exhibited a significant increasing tendency and then decreased with the successive generations thereafter. The percentage of parasitized eggs and number of emerged adults per egg were increased from 40.0% and 10.8 adults/egg in F1 generation to 86.7% and 36.4 adults/egg in F4 generation respectively. In addition, T. leucaniae reared on A. pernyi for four generations significantly parasitized more SPB eggs regardless of egg age compared with those reared on Corcyra cephalonica eggs. These results provided useful information on the feasibility of mass production of T. leucaniae by reared for successive generations on A. pernyi large eggs., Competing Interests: The authors have declared that no competing interests exist.

Bracoviruses associate symbiotically with thousands of parasitoid wasp species in the family Braconidae, working as virulence gene vectors, and allowing the development of wasp larvae within hosts. These viruses are composed of multiple DNA circles that are packaged into infective particles, and injected together with wasp's eggs during parasitization. One of the viral segments of Cotesia vestalis bracovirus contains a gene that has been previously described as a helicase of unknown origin. Here, we demonstrate that this gene is a Rep/Helicase from an intact Helitron transposable element that covers the viral segment almost entirely. We also provide evidence that this element underwent at least two horizontal transfers, which appear to have occurred consecutively: first from a Drosophila host ancestor to the genome of the parasitoid wasp C. vestalis and its bracovirus, and then from C. vestalis to a lepidopteran host ( Bombyx mori ). Our results reinforce the idea of parasitoid wasps as frequent agents of horizontal transfers in eukaryotes. Additionally, this Helitron-bracovirus segment is the first example of a transposable element that effectively became a whole viral circle., (Copyright © 2017 Heringer et al.)

Palmistichus elaeisis Delvare and LaSalle (Hymenoptera: Eulophidae) is a gregarious and polyphagous parasitoid mainly of Lepidoptera pupae. The objective of this paper as to study the developent of parasitoid on Bombyx mori L. (Lepidoptera: Bombycidae) pupae exposed to one, nine, 18, 27, 36, 45 or 54 female P. elaeisis, respectively. The females of the parasitoid remained in contact with pupae for 24 hours in glass tubes (14.0 x 2.2 cm), packed in a climatic chamber regulated at 25 +/- 2 degrees C, 70 +/- 10% relative humidity and photo phase of 12 hours. With the exception of density 1:1 (72.72%), in other densities parasitism was 100%. Adults of P. elaeisis did not emerge from pupae at densities of 1:1 and 9:1, but 100.0% of parasitoid emergence was observed at the density of 45:1 and 54.54% at 54:1. The duration of the life cycle of this parasitoid ranged from 20 to 28 days. P. elaeisis produced 49 to 589 descendants per pupa of B. mori. The sex ratio of P. elaeisis ranged from 0.93 +/- 0.01 to 0.97 +/- 0.01 without differences with 18, 27, 36, 45 and 54 females/host. This parasitoid should be reared with the density of 45 females per pupa of B. mori.

The mass rearing of parasitoids represents a fundamental stage for programmes of biological control. The progeny of the parasitoid Palmistichus elaeisis Delvare and LaSalle (Hymenoptera: Eulophidae) were evaluated on previously refrigerated pupae of Bombyx mori L. (Lepidoptera: Bombycidae). Forty-eight to 72 hours-old pupae of B. mori were stored at 10 degrees C for five, 10, 15 or 20 days and then exposed to parasitism by P. elaeisis females. This parasitoid showed shorter duration of the life cycle when reared on pupae of B. mori which were previously stored at 10 degrees C during 15 days. P. elaeisis parasitized 100% of the pupae of B. mori after storage at 10 degrees C during all periods with emergence of this parasitoid from 78 to 100% of these pupae. P. elaeisis had a higher number of progeny per pupa of B. mori stored for 15 days at 10 degrees C. Pupae of B. mori can be stored for 15 days at 10 degrees C before being used to rear P. elaeisis.