Effect of Styrofoam Waste Feeds on the Growth, Development and Fecundity of Mealworms (Tenebrio molitor)

Abstract

It has been reported that Styrofoam can be biodegraded by Tenebrio molitor beetle larvae within a retention time of less than 24 h and the larvae fed solely with Styrofoam able to survive for more than a month. The question is whether Styrofoam can be used as an economical feed in the cultivation of mealworms? To determine productivity effect of Styrofoam feeds on mealworms, the larvae (n = 120) were grouped into three. Group 1, 2 and 3 were cosecutively fed with yeasts (as the standard diet), Expanded Polystyrene (EPS) and Extruded Polystyrene (XPS) were used. The observations take place in two stages. At stage 1, measurements were made on percent survival of the caterpillar, larval weight, prepupal periods, pupation periods, pupal weight and imago weight. At stage 2, the imago emerged from the pupae were separated between males and females and then mated. The number of eggs laid by the imago females in ten days are noted. The results showed, in comparison to the standard diet, EPS and XPS foam feeds did not give a significant effect on the mortality of the larvae. Both types of Styrofoam promote a significant longer periods of prepupal and pupation and significantly reduce number of eggs. Compared with yeasts and EPS foam, only XPS showed a lower weight of larvae, pupae and imago. It is inferred that the Styrofoam is not worthy as economical feeds in mealworms cultivation. However, given that Styrofoam feeds can maintain the insects life and produce eggs, the use of mealworms in polystyrene foam waste degradation is still worth considering.

Insects as food and feed, a new emerging agricultural sector: a review

“…Styrofoam, expanded polystyrene foam, such as disposable cups and boxes, or cushioning material in packaging, have been proposed for degradation by the yellow mealworm. However, although the foam feeds can maintain the insect's life and produce eggs, it was not economically feasible (Nukmal et al, 2018). Tenebrio obscurus has also been proposed as a likely candidate to be able to degrade plastics (Peng et al, 2019).…”

Growth and survivability of the black carpet beetle fed a whole feather diet

“…It is not uncommon for insects to exhibit stunted growth while reared on waste streams, although this is not always the case and is highly contingent upon the waste source itself. In a study analysing the impact of a Styrofoam diet in the growth and survivability of mealworms, mealworms fed Styrofoam had stunted growth and longer pupation times compared with the specimens reared on the typical yeast diet, although did not exhibit a difference in survivability (Nukmal 2018). This is not dissimilar to what was found in this study, although survivability in this case was adversely affected.…”

Immune Defenses of a Beneficial Pest: The Mealworm Beetle, Tenebrio molitor

“…As previously mentioned, another growing interest for T. molitor concerns its ability to digest polystyrene foam. While polystyrene foam decreases T. molitor fecundity ( Nukmal et al., 2018 ), the insect can fully develop using the plastic as its primary source of food. This makes the insect a relevant alternative to recycle polystyrene.…”