Mineral analysis reveals extreme manganese concentrations in wild harvested and commercially available edible termites

Abstract

Termites are widely used as a food resource, particularly in Africa and Asia. Markets for insects as food are also expanding worldwide. To inform the development of insect-based foods, we analysed selected minerals (Fe-Mn-Zn-Cu-Mg) in wild-harvested and commercially available termites. Mineral values were compared to selected commercially available insects. Alate termites, of the genera Macrotermes and Odontotermes, showed remarkably high manganese (Mn) content (292–515 mg/100 gdw), roughly 50–100 times the concentrations detected in other insects. Other mineral elements occur at moderate concentrations in all insects examined. On further examination, the Mn is located primarily in the abdomens of the Macrotermes subhyalinus; with scanning electron microscopy revealing small spherical structures highly enriched for Mn. We identify the fungus comb, of Macrotermes subhyanus, as a potential biological source of the high Mn concentrations. Consuming even small quantities of termite alates could exceed current upper recommended intakes for Mn in both adults and children. Given the widespread use of termites as food, a better understanding the sources, distribution and bio-availability of these high Mn concentrations in termite alates is needed.

Presence of metals in farmland edible termites in Mazabuka District, Zambia

“…The respondents described alates and soldier termites (99.7%), flying ants (85.9%), caterpillars (84.5%), grasshoppers (83.1%), crickets (63.3%), stink bugs (62.7%) and long-horned beetles (4.1%) as edible insects, in the farmlands with Macrotermes genera of termites predominately being eaten as food and feed, with a frequency percentage (94.2%) as shown in Figure 2. The findings of this study are in line with those of Verspoor et al (2020). Soldiers and alates were used as both food and feed.…”

“…It has therefore been established that termites would serve as a media for heavy metals pick-up due to their feeding on soil as well as termitarium construction and in the process accumulate metals in their bodies (Denloye et al, 2015;Musa et al, 2014). In addition the range and source of difference in mineral content within and between species remains largely unknown (Verspoor et al, 2020). Literature reviews show that most of the studies on edible insects, are on nutritional composition, and studies on the safety of the edible insects as regards to heavy metals are still limited, especially in Africa (Imathiu, 2020;Murefu et al, 2019).…”

A Critical Review on the Multiple Roles of Manganese in Stabilizing and Destabilizing Soil Organic Matter

“…Certain Basidiomycetes are highly effective wood degraders due in part to their production of Mn peroxidase enzymes that act as biocatalysts to degrade lignin . Cultivated fungal combs can concentrate Mn to levels nearly 10 3 × the surrounding soil, and termites that ingest these combs contain 100× more Mn than other insects and store unique Mn nodules in their abdomens . Given that fungal-farming termites are important ecosystem engineers in many arid environments, Mn may be an unrecognized supporter of these ecosystems through its ability to enhance lignin degradation.…”

A Comprehensive Review of the Importance of Selected Trace Elements Present in Edible Insects

“…Some of the common documented edible insects rich in trace elements include beetles, caterpillars, ants, grasshoppers, locusts, crickets, stinkbugs, termites, flies, and cockroaches [3,5,33,34]. For example, edible insects such as termites, mopane worms, house crickets, yellow mealworms, and locusts contain extremely high Mn contents compared to other insects [14,22,35]. According to Payne et al [22], high Mn in insects may be caused by factors such as soil and water composition found in the origin of insects.…”