Black Soldier Fly School Workshops as Means to Promote Circular Economy and Environmental Awareness

Today, insect applications for food and feed are of strong economic, ecological and social interest. Despite their tremendous potential, insects still elicit negative associations in the mindset of Western consumers, which is attributed to a lack of knowledge and scarce opportunities for engagement in this topic. The citizen science project ‘six-legged livestock’ aims to increase the potential of the insect Hermetia illucens (black soldier fly), merging the topics ‘waste re-valorisation’ and ‘protein production’ as a cross-link to circular economy. Workshops were held in four school classes, involving 89 pupils, aged 15 to 18 years old. Making use of organic wastes, participating school classes ran eight rearing systems containing a total of 1800 H. illucens larvae. In the four-week experiments, the pupils monitored larval growth and development. Evidently, the pupils were highly motivated to run their rearing systems and fulfil their working tasks. Furthermore, negative associations with insects, including phobia and scepticism decreased, while excitement for the topic increased after hands-on work with the insects. The presented project may be considered an innovative approach paving the way for the establishment of insects as an important educational tool, since they are still underrepresented in scholarly curricula, despite the public outrage over insect decline

Correction: Influence of three artificial light sources on oviposition and half-life of the Black Soldier Fly, Hermetia illucens (Diptera: Stratiomyidae): Improving small-scale indoor rearing.

[This corrects the article DOI: 10.1371/journal.pone.0197896.]

Identifying the minimum number of microsatellite loci needed to assess population genetic structure: A case study in fly culturing

<p>Small, isolated populations are constantly threatened by loss of genetic diversity due to drift. Such situations are found, for instance, in laboratory culturing. In guarding against diversity loss, monitoring of potential changes in population structure is paramount; this monitoring is most often achieved using microsatellite markers, which can be costly in terms of time and money when many loci are scored in large numbers of individuals. Here, we present a case study reducing the number of microsatellites to the minimum necessary to correctly detect the population structure of two <i>Drosophila nigrosparsa</i> populations. The number of loci was gradually reduced from 11 to 1, using the Allelic Richness (AR) and Private Allelic Richness (PAR) as criteria for locus removal. The effect of each reduction step was evaluated by the number of genetic clusters detectable from the data and by the allocation of individuals to the clusters; in the latter, excluding ambiguous individuals was tested to reduce the rate of incorrect assignments. We demonstrate that more than 95% of the individuals can still be correctly assigned when using eight loci and that the major population structure is still visible when using two highly polymorphic loci. The differences between sorting the loci by AR and PAR were negligible. The method presented here will most efficiently reduce genotyping costs when small sets of loci (“core sets”) for long-time use in large-scale population screenings are compiled.</p

Influence of three artificial light sources on oviposition and half-life of the Black Soldier Fly, Hermetia illucens (Diptera: Stratiomyidae): Improving small-scale indoor rearing.

Hermetia illucens (L.), the Black Soldier Fly, has received increased scientific attention for its potential in circular waste management where larvae can serve as feedstuff for livestock and for biodiesel production. The flies occur naturally in (sub)-tropical and warm-temperate climates, and their mating depends on space and sunlight. Small-scale indoor rearing of Black Soldier Flies has been challenging because they react sensitive to artificial light sources and cage sizes, but recent studies have shown that small-scale rearing under artificial light is feasible. Here, we test the influence of three artificial light sources (light-emitting diodes, fluorescent lamps, and halogen lamps) on small-scale indoor rearing. Three experiments were conducted to compare oviposition traits (pre-oviposition period, total oviposition-period, and egg mass per female) and half-life among the three light sources. Oviposition did not differ among the three light sources, but male and female half-life did. Based on the performance of the light-emitting diodes and their outstanding energy efficiency, we recommend this light source for small-scale indoor rearing of Black Soldier Flies

Light spectra (μmol m^-2 s^-1) of three artificial light sources: 1) light-emitting diode (LED, green); 2) fluorescent lamp (FL, blue); and 3) halogen lamp (HL, amber) at wavelengths from 300 to 885 nm.

<p>Light spectra (μmol m^-2 s^-1) of three artificial light sources: 1) light-emitting diode (LED, green); 2) fluorescent lamp (FL, blue); and 3) halogen lamp (HL, amber) at wavelengths from 300 to 885 nm.</p

Top view of the position of the three light sources: 1) light-emitting diode (LED, green); 2) fluorescent lamp (FL, blue); and 3) halogen lamp (HL, amber); the contours of polyethylene cages are drawn in black.

<p>Top view of the position of the three light sources: 1) light-emitting diode (LED, green); 2) fluorescent lamp (FL, blue); and 3) halogen lamp (HL, amber); the contours of polyethylene cages are drawn in black.</p

Male and female survival under three artificial light sources: 1) light-emitting diode (LED, green); 2) fluorescent lamp (FL, blue); and 3) halogen lamp (HL, amber) during the 15 days for Experiment 1 [a], Experiment 2 [b], and Experiment 3 [c].

<p>Male and female survival under three artificial light sources: 1) light-emitting diode (LED, green); 2) fluorescent lamp (FL, blue); and 3) halogen lamp (HL, amber) during the 15 days for Experiment 1 [a], Experiment 2 [b], and Experiment 3 [c].</p