Performance of Trichogramma japonicum under field conditions as a function of the factitious host species used for mass rearing

Different factitious hosts were used to mass rear Trichogramma japonicum Ashmead in different parts of the globe because thorough details were lacking in both the laboratory and the field. The objective of this study was to compare, parasitoid, T. japonicum reared in different factitious hosts. Three commonly used factitious host eggs, Corcyra cephalonica (Stainton), Ephestia kuehniella Zeller and Sitotroga cerealella Olivier were tested under laboratory conditions and then in the field over a yellow stem borer, Scirpophaga incertulus (Walker) of rice. The highest parasitism by T. japonicum was observed on E. kuehniella eggs. The parasitoid’s highest emergence (88.99%) was observed on S. cerealella eggs at 24 h exposure, whereas at 48 h it was on E. kuehniella eggs (94.66%). Trichogramma japonicum females that emerged from E. kuehniella eggs were significantly long-lived. The days of oviposition by hosts and the host species were significant individually, but not their interaction. Higher proportions of flying T. japonicum were observed when reared on E. kuehniella and C. cephalonica eggs. Field results showed that T. japonicum mass-reared on E. kuehniella showed higher parasitism of its natural host, S. incertulus eggs. Hence, by considering these biological characteristics and field results, E. kuehniella could be leveraged for the mass rearing of quality parasitoids of T. japonicum in India, the Asian continent and beyond.

Space and Shelter Requirement of Nymphs in the Mass-Rearing of the Edible Ruspolia differens (Orthoptera: Tettigoniidae)

The ability to mass-rear insects in high densities is a precondition for the edible insect industry but the space requirement has to be determined specifically for each species. Mass-rearing methods for Ruspolia differens Serville (Orthoptera: Tettigoniidae), one of the most consumed edible insect species in East Africa, are currently lacking. Though, these methods are urgently needed to enhance the food security in the region and to reduce the pressure on the wild populations. Here, we experimentally evaluated the effect of rearing density and rearing environment on the survival of R. differens nymphs. We conducted two experiments; in Experiment 1 we used small 0.15-liter rearing containers and in Experiment 2, larger 0.75-liter containers. The rearing densities ranged from 4 to 300 individuals per liter and we used three different rearing environments (‘net’, ‘spikes’, and ‘oat sprouts’). We found that the survival of R. differens nymphs is strongly density-dependent. The suitable rearing density for young R. differens nymphs should be ≤36 nymphs per liter, as in higher densities the mortality of nymphs increases rapidly over the course of time. With rearing densities ≤36 nymphs per liter, a survival rate of 60% can be expected up to 28 d after rearing. The studied environments only had a minor effect on the survival. These results create the basis for the efforts to upscale the rearing of R. differens in the future.

‘Minilivestock’ farming: Who is farming edible insects in Europe and North America?

An innovative food sector is emerging in North America and Europe: edible insects. Eating insects is not new; farming insects for human consumption is novel. This article provides an overview of entomophagy to contextualise this upsurge in ‘minilivestock’ farming. It also charts the rise of ‘feeder’ insect farms, because their ability to mass rear invertebrates – for exotic pets, reptiles and other insectivores – is of much interest to those starting and intensifying edible insect farms. A descriptive characterisation of frontier farmers will be provided by preliminary profile findings from 17 semi-structured pilot interviews with people with varying experience of rearing feeder and/or food insects. Since conventional livestock workers were the ‘forgotten pillar’ in agricultural research, this article affords timely insights into the socio-demographic characteristics, lifestyle interests and farming experiences of ‘entopreneurs’ shaping this new ‘insect industry’.

Validation of a methodology for rearingSpalangia cameroni(Hymenoptera: Pteromalidae) onCeratitis capitata(Diptera: Tephritidae)

Spalangia cameroniPerkins (Hymenoptera: Pteromalidae) is a pupal parasitoid of the Medfly,Ceratitis capitata(Wiedmann) (Diptera: Tephritidae), one of the principal pests of Spanish agriculture.Spalangia cameroniis a potential biocontrol agent for this pest if methods can be developed to mass-rear it effectively onC. capitata. Here, we report on the use of freeze-killed pupae ofC. capitatato maintain a laboratory colony ofS. cameroni, with a view to setting up a mass-rearing protocol. Realised fecundity, adult progeny, sex ratio, and superparasitism level were the principal parameters analysed. No significant differences were found in respect of these parameters between living or freeze-killed Medfly pupae used as hosts, although sex ratios showed a bias towards females in the case of freeze-killed pupae. Freeze-killed pupae were concluded to present the best option for the laboratory-rearing ofS. cameroni, on account of ease of rearing, and avoidance of the emergence of Medfly adults.

Development, Preimaginal Phases and Adult Sensillar Equipment in Aganaspis Parasitoids (Hymenoptera: Figitidae) of Fruit Flies

Aganaspis daci and Aganaspis pelleranoi (Hymenoptera: Figitidae) are important parasitoids of fruit flies. Here we studied, with light and scanning electron microscopy, aspects of their morphology that could help with plans to mass rear and thus contribute to improved pest control (preimaginal phases) and to shed light on parasitoid-pest relationships (sensillar equipment). The two species present a stalked egg, eucoiliform first and second-instar larvae and hymenopteriform third instar and mature larvae. The first instar presents tegumental differentiations in the mesoma and first metasomal segment in A. daci, but not in A. pelleranoi, while unlike other figitids, neither species displays setae in the mesosomal processes. Second and third instar and mature larvae present tegumental differentiations in A. daci, but not in A. pelleranoi. The moniliform (female) and filiform (male) antennae of A. daci and A. pelleranoi harbor seven types of sensilla, four of them (sensilla campaniformia, sensilla coeloconica type II, and two types of sensilla trichoidea) described here for the first time in Cynipoidea. The largest sensilla were the multiporous placoid sensilla, which were smaller and more numerous in A. pelleranoi. Species also differed to some extent in morphology of sensilla coeloconica. Observations on the ovipositor revealed the presence of coeloconic sensilla on Valva I in both species.

Aphid parasitoids in biological control

Boivin, G., Hance, T. and Brodeur, J. 2012. Aphid parasitoids in biological control. Can. J. Plant Sci. 92: 1–12. Aphids are important pests of most cultivated crops worldwide. Among the natural enemies that regulate their populations, aphid parasitoids are commonly used in biological control programs in greenhouses and field situations. They belong to the Hymenoptera (Braconidae and Aphelinidae), and a few species are Diptera (Cecidomyiidae). Aphid parasitoids are themselves exposed to a variety of natural enemies including predators, fungi and hyperparasitoids. The most important impediment to the use of aphid parasitoids as biological control agents remains the production cost to mass-rear parasitoids. Rearing either aphids or directly aphid parasitoids in artificial media could be a solution to produce large quantities of aphid parasitoids at low cost, but such an approach still faces numerous challenges related to the nutritional and physiological requirements of developing aphid parasitoids.