Nutritional indices and feeding preference of the Plutella xylostella L. (Lepidoptera: Yponomeutidae) in several Brassicaceae plants

The quantity and quality of food consumed by insects affect their growth, development; likewise, the diamondback moth Plutella xylostella (Lepidoptera: Yponomeutidae), one of the important pests of Brassicaceae plants. The study aimed to determine feed preferences and the effect of four Brassicaceae, namely cabbage (Brassica oleracea var. capitata), caisin (B. rapa), broccoli (B. oleracea var. italica), and Rorippa indica, on the nutritional indices of P. xylostella larvae. The research methods consisted of insect rearing, nutrition indices test, preference test, and proximate analysis. The results showed that the highest preference was found in R. indica (47.81%), while the other three plant species were not significantly different. Cabbage treatment showed the highest efficiency of conversion of ingested food (ECI) (8.56%), followed by R. indica, caisin, and broccoli. The same thing, cabbage treatment showed the highest efficiency of conversion of digested food (ECD) (13.02%), followed by caisin, R. indica, and broccoli. Broccoli had the highest approximate digestibility (AD) (89.38%), followed by R. indica, cabbage, and caisin. In general, the results of the nutritional indices showed that cabbage was the most suitable feed for P. xylostella larvae; in addition, with a high feeding preference, R. indica could potentially be used as a trap crop.

Insect rearing protocols in forensic entomology: Benefits from collective rearing of larvae in a carrion beetle Necrodes littoralis L. (Silphidae)

Forensic entomologists frequently use a developmental method to estimate a post-mortem interval (PMI). Such estimates are based usually on the blow fly larvae or puparia. Data on their development is obtained by rearing them in colonies. In the case of beetles, which can be also useful for PMI estimation, development data is frequently collected by rearing them individually. However, some carrion beetles are gregarious, for instance, Necrodes littoralis (Linnaeus, 1758) (Silphidae). We compared mortality, rate of development and body size of emerged adult beetles reared individually and in aggregations. Mortality was much higher for beetles reared individually, particularly at low temperatures. The rearing protocol affected the time of immature development and the size of adult insects. Individually reared specimens developed much longer at 16°C, whereas at 20°C and 26°C development times of individually reared beetles were slightly shorter. Significant differences in the body size were observed only at 16°C; beetles that developed in aggregations were larger at this temperature. These findings demonstrate that aggregating is particularly beneficial for larvae of N. littoralis at low temperatures, where it largely reduces mortality and facilitates growth. Moreover, these results indicate that in forensic entomology the protocol of individual rearing is unsuitable for gregarious beetles, as it produces reference developmental data of low quality.

Recent Advances in Insect Rearing Methodology to Promote Scientific Research and Mass Production

The benefits obtained from our ability to produce insects have encompassed a wide array of applications, from the early stages of examining different species, to the present day of mass production for multiple purposes [...]

Entomoponics: combining insect rearing and greenhouse vegetable production – a case study with Tenebrio molitor and high-wire cucumber cultivation

Insect production is generally a monoculture where insects are kept in an enclosed environment with a stable climate to maximise production. To maintain these conditions air treatment is necessary, which results in high operational costs. Combining insect rearing with hydroponic greenhouse cultivation (HGC) of fruit vegetables might offer an opportunity for cost reduction. Fruit vegetables generally require more elevated air temperature, while leaving enough space under the substrate supporting gutters to allow insect rearing. In this study the feasibility of combining both production systems was evaluated with mealworms (Tenebrio molitor) and cucumber HGC serving as model species. The influence of the greenhouse climate was assessed by rearing mealworms simultaneous at two locations (a climate room and a cucumber HGC). Furthermore, pruning waste and aesthetically declined fruits could serve as a feed for insects. This was tested by comparing 4 different wet feeds (whole and mashed cucumber pruning, tomatoes and agar-agar). Larval growth was monitored and at harvest the mealworm yield was compared among treatments. Mealworm growth in the greenhouse was on average 8.1% slower than growth in a climate room even though the average ambient temperature in the greenhouse was lower and more variable (22.1±3.30 °C standard deviation compared to 27.0±0.34 °C). Moreover, the results showed that the tested HGC residues can be used as wet feed given that mashed cucumber pruning gave similar results as agar-agar (control) and tomatoes even outperformed the control significantly in terms of growth. ‘Entomoponics’ is introduced as the name for the combination of insect production and HGC of vegetables as a way to create added value in unused heated space inside a greenhouse and valorise greenhouse residues.

A Novel Concept for Sustainable Food Production Utilizing Low Temperature Industrial Surplus Heat

Low temperature industrial surplus heat represents a major energy source that is currently only rarely utilized due to its low quality. An agricluster allows for the leveraging of this low-quality heat and, hence, may improve the overall energy efficiency. This paper presents the novel concept of an agricluster driven by available surplus heat from industrial processes. We propose the integration of greenhouse production, insect rearing, fish rearing, and drying of seaweed using low temperature surplus heat from the aluminum industry. Each of these processes is already used in or investigated for utilization of surplus heat and partly coupled with other processes, such as in aquaponics. However, the integration of all processes in an agricluster—as proposed in this paper—may result in improved utilization of the surplus heat due to the different seasonality of the heat demand. The potential synergies of this integration approach are discussed in this paper. Furthermore, waste from one process can be utilized as an input stream to other processes, reducing the demand for external material input to the system. The proposed concept of an agricluster is especially interesting for the Nordic countries, as they are dependant on fresh food imports due to the low outside temperatures.