pH of Substrate Impacts Black Soldier Fly Development

Myself and Junhua Ma in China. Junhua helped me engage students at his university on the topic of critical thinking (September 2017).

Hey All-

In previous posts, we have discussed many abiotic factors that impact BSF growth and production ; however, a new article was just published from a join effort with my colleagues in China (Longyu Zheng & Jibin Zhang).  The topic covered was pH.

Ma, J., Y. Lei, K. u. Rehman, Z. Yu, J. Zhang, W. Li, Q. Li, J. K. Tomberlin, and L. Zheng. 2018. Dynamic effects of Initial pH of substrate on biological growth and metamorphosis of black soldier fly (Diptera: Stratiomyidae). Environmental Entomology: nvx186-nvx186.

​My first set of comments is with regards to the first author- Junhua Ma.  Our first encounters were via email with regards to this study and the resulting publication. However, I had a chance to meet him in person this past year and I made a few observations about him (and maybe myself).  

1. He is an undergraduate student!! I was so very impressed with his efforts as a student pursuing his BS degree. To invest the time and produce such a high quality study. His maturity is simply impressive!  I hope that there are other undergraduates, or producers, out in the world reading this blog and are inspired to conduct their own research.  

2. My second observation?  I am getting OLD!!!!! Man- when I met Junhua in person... I thought he was in secondary school!!!  

Well- enough about Junhua Ma!  He has a bright future in research as he is aiming to pursue his PhD in the USA.

Now- how about his (our) paper?  What are the major conclusions?

​First- you should recognize their goal was to determine the impact of initial pH (important factor- not long term pH... over time) of diet on larval development. This could be a critical component of any system when you consider if you do single feeding (batch) or continual feeding.  With continual feeding, you would be adding food periodically to the larval container- which means the larvae are continuously exposed to a set medium pH. On the other hand, if you do a single feeding system, you would be only exposing them to the medium pH one time and then the larvae would modify the pH to a more optimal condition for them to develop (of course, assuming they can modify the pH).

Second- they determined initial pH did impact larval final weights. For larvae exposed to a slightly acidic diet (6.0), larvae were 23% larger than those reared on a more acidic (pH = 2 or 4). 

Third- the same results were determined for prepupae (22% larger on the slightly acidic diet, pH = 6.0 rather than the more acidic medium, pH = 2.0/4.0).

Fourth- pH impacted development with those reared on the slightly acidic diet finishing developing 3 days faster.

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Author

Jeffery K Tomberlin, PhD
Twitter: @FliesFacility
​Director, EVO Conversion Systems