Oak Silk Moth Antheraea Pernyi Research Articles

Performance and Cost Comparisons for Continuous Rearing of Arma chinensis (Hemiptera: Pentatomidae: Asopinae) on a Zoophytogenous Artificial Diet and a Secondary Prey

The impact of a zoophytogenous, insect-free artificial diet and a secondary prey, pupae of Chinese oak silk moth Antheraea pernyi (Guérin-Méneville) (Lepidoptera: Saturniidae), on the developmental rate, life history parameters, and fertility was examined for F6, F9, and F12 consecutive generations for domesticated Arma chinensis (Fallou) (Heteroptera: Pentatomidae). This study showed that when fed an insect-free artificial diet during both the nymphal and adult stages, developmental times were prolonged, and fecundity, egg viability, net reproductive rates (R0), and intrinsic rates of increase (rm) declined. As a result, the cost to rear A. chinensis on the artificial diet approached 1.7 times the cost of rearing A. chinensis on pupae of A. pernyi. Future diet improvements should attempt to reduce developmental time, increase fecundity, and egg viability and use less costly nutrient sources.

Characterization of insect cytosolic juvenile hormone binding protein gene: Highly homology with vertebrate glyoxalase domain containing protein 4

Cytosolic juvenile hormone binding protein (cJHBP) is a carrier of juvenile hormone (JH) in insects, however knowledge about its evolution and expression remains extremely limited. In this study, a gene encoding for cJHBP was isolated from the Chinese oak silkmoth Antheraea pernyi. A database search showed that the homologous sequences were present in several animal species including nematodes, insects, tunicates, fish, and mammals. The A. pernyi cJHBP had 54–85% identity with its homolog from other insects, and 58–62% identity with vertebrate glyoxalase domain containing protein 4 (Glod-4). Phylogenetic analysis supported the hypothesis that insect cJHBP shares a common ancestor with vertebrate Glod-4. RT-PCR detection showed that the cJHBP gene was expressed throughout the developmental stages and in all tested tissues of A. pernyi, which agreed with the data from Bombyx mori cJHBP and Homo sapiens Glod-4. These data suggest that insect cJHBP may play a similar function as vertebrate Glod-4.

A meridic diet for continuous rearing of Arma chinensis (Hemiptera: Pentatomidae: Asopinae)

An artificial diet comprised of pig liver and tuna fish but devoid of insect components was developed for continuous rearing of the predator Arma chinensis Fallou. Our results demonstrated less desirable biological parameters in A. chinensis reared on this artificial diet compared to a secondary prey, pupae of Chinese oak silk moth Antheraea pernyi Guérin-Méneville. Weight of eggs and adults, fecundity and egg viability were lower for diet-fed A. chinensis compared to A. chinensis reared on pupae of A. pernyi. Developmental time from 2nd instar to adult and the preovipositional period were significantly longer for diet-fed A. chinensis. Cannibalism was also higher with diet-fed A. chinensis. Over successive generations of rearing on the diet some of the characteristics improved, such as developmental time, survival from 2nd instar to adult, sex ratio (♂:♀), adult weight, fecundity and fertility. These changes may indicate that the predators experience some degree of adaptation to, or genetic selection for, the diet after several consecutive generations. There were no changes in developmental time of egg and 1st instar, or survival from 1st to 2nd instar with successive generations reared on the artificial diet. However, diet-fed adults did live longer than pupae-fed adults.

The potential of trehalose to replace insect hemolymph in artificial media for Trichogramma dendrolimi (Hymenoptera: Trichogrammatidae)

Insect additives have been shown to improve the value of artificial media for Trichogramma species, but at the same time maintain dependence on parallel cultures of host insects. In the present study, Trichogramma dendrolimi Matsumura was reared in vitro from egg to adult on artificial media with different contents of pupal hemolymph of Chinese oak silkmoth Antheraea pernyi (Guérin-Méneville) and with supplements of distilled water, or of trehalose dissolved in water or in Grace's insect medium. The results indicated insect hemolymph was the key component of artificial medium. Developmental parameters, including rates of parasitism, pupation, adult emergence and normal adults, and numbers of produced adults, were increased on media supplemented with trehalose even when the proportion of pupal hemolymph was reduced. Two artificial media, the first containing 30% hemolymph and 10% trehalose in water with 98.9% parasitism rate, 77.7.0% pupation rate, 77.2% emergence rate, 80.0% normal adult rate and 333 produced adults, and the second containing 25% hemolymph and 15% trehalose in Grace's insect medium with 97.8% parasitism rate, 91.0% pupation rate, 85.2% emergence rate, 76.1% normal adult rate and 757 produced adults, were believed to hold potential to mass produce T. dendrolimi. The use of trehalose to partially replace pupal hemolymph in artificial medium of this and other Trichogramma species may contribute to a significant reduction in their production cost and may as such help to evade problems related to short supplies of lepidopteran eggs, which currently constitute the main factitious host for the mass rearing of the parasitoids.

The Nuclear Apparatus and Chromosomal DNA of the Microsporidian Nosema antheraeae

The microsporidian Nosema antheraeae is a pathogen of the Chinese oak silkmoth Antheraea pernyi, the molecular karyotype of which is still poorly understood. Here the diplokaryon of N. antheraeae strain NP-YY has been visualized both by fluorescence and electron microscopy. In addition, pulsed-field gel electrophoresis (PFGE) showed that the haploid genome of N. antheraeae is approximately 9.3-9.5 million base pairs organized into 15 chromosomal bands. The mean fluorescence intensity of N. antheraeae and Nosema bombycis DNA measured by flow cytometry confirmed that the genome size of these two species was congruent with measurements obtained by PFGE. These initial results on the chromosome organization of N. antheraeae provide a foundation for the comparative genomics of N. antheraeae with other species of Nosema.

Cloning, expression and phylogenetic analysis of Hemolin, from the Chinese oak silkmoth, Antheraea pernyi

The Chinese oak silk moth Antheraea pernyi is an important silk producer. To understand microbial resistance of this moth, we cloned Hemolin, encoding a multifunctional immune protein belonging to the immunoglobulin superfamily, and examined the expression in gonads and fat body. The ApHemolin amino acid sequence was compared to other Hemolin sequences in order to predict functional sites. Several sites were conserved; among them a phosphate binding site, which according to 3D structure modelling does not appear in neuroglian, the phylogenetically closest related protein. In addition, two conserved KDG sequences in the C–C′ loop of immunoglobulin domains 1 and 3, give rise to γ-turns, which is a common motif in the C′–C″ loop of the hypervariable region L2 in vertebrate immunoglobulins. The comparisons also show variable regions of specific interest for future studies of hemolin and its interaction with microbial entities.

Regulation of the haemolymph osmolality during metamorphosis in the oak silk moth Antheraea pernyi

The total loss of weight during metamorphosis is about 80 per cent, whereas during pupal life the loss is about 10 per cent. During silk production there is an increase in haemolymph osmolality and ninhydrin-positive substances (NPS). Both the haemolymph osmolality and the haemolymph NPS concentration are constant during the pupal stage and show a decrease during the pharate adult stage. The relative water content of the pupa rises from 77 to 81 per cent between pupation and emergence. Two fluid compartments in the gut show a high content of NPS and a high osmolality. Their participation in osmotic regulation is discussed.