Scientists found a new recipe for feeding tobacco cutworm caterpillars that costs less money and helps them grow faster and healthier. By swapping soybean flour for corn flour in the caterpillar food, researchers created a diet that saves farms about 6% on costs while producing bigger, more fertile insects. This matters because these caterpillars are used to breed tiny wasps that farmers release to control pests naturally. The new diet could help farms produce more beneficial insects cheaply, making natural pest control more affordable for farmers around the world.

The Quick Take

  • What they studied: Whether changing the ingredients in artificial caterpillar food—especially using corn flour instead of soybean flour—could make the insects grow better while costing less money
  • Who participated: Laboratory experiments with tobacco cutworm caterpillars (Spodoptera litura) raised under controlled conditions with consistent temperature, humidity, and light
  • Key finding: The new diet formula (number 15) made caterpillars develop 2-3 days faster, grow 25% heavier, lay 2,658 eggs per female instead of fewer, and cost 5.9% less to produce than the original diet
  • What it means for you: If you’re a farmer using natural pest control methods, this research suggests you could save money while getting better results. However, these findings are from laboratory tests, so real-world farm results may vary depending on local conditions

The Research Details

Researchers created 18 different recipes for artificial caterpillar food by starting with a standard diet and changing the ingredients, particularly replacing soybean flour with corn flour. They organized these recipes into three groups based on cost: expensive, medium-priced, and cheap. Each diet was tested with caterpillars kept in identical laboratory conditions—the same temperature (26°C), humidity (70%), and light schedule (16 hours light, 8 hours dark).

The scientists measured how well the caterpillars grew on each diet by tracking how long it took them to develop from caterpillar to adult, how heavy they became, how many eggs the females laid, and how many of those eggs successfully hatched. They also calculated population growth rates to understand how quickly the insect population would expand under each diet.

This type of controlled laboratory study allows researchers to test one variable at a time (the diet ingredients) while keeping everything else the same, making it easier to see which diet changes actually made a difference.

This research approach is important because farmers who use natural pest control need to breed millions of beneficial insects cheaply and efficiently. By testing different diet recipes in controlled conditions first, scientists can find the best formula before recommending it to farms. This saves farmers money and time compared to testing expensive changes on their own.

This study was published in a peer-reviewed scientific journal, meaning other experts reviewed the work before publication. The researchers used controlled laboratory conditions, which makes results reliable and repeatable. However, the study only tested caterpillars in a lab environment, not on actual farms, so real-world results might differ slightly. The sample size for individual diet tests isn’t specified in the abstract, which is a limitation for understanding how many insects were tested per diet.

What the Results Show

The best-performing diet (formulation 15) significantly outperformed the original diet across multiple measures. Caterpillars on this new diet completed their larval stage (the caterpillar phase) in just 19.52 days compared to longer periods on other diets, and their pupal stage (the transformation phase) took only 10.46 days. The insects grew heavier, reaching an average of 500 milligrams, which is important because larger insects typically produce more offspring.

Females raised on this diet laid an average of 2,658 eggs each—a substantial increase in reproduction. Additionally, 73.77% of these eggs successfully hatched into caterpillars, showing excellent egg quality. These improvements mean that farms using this diet would produce more insects in less time.

The population growth calculations showed that the new diet allowed the insect population to increase faster and more efficiently than with the original diet. Specifically, the intrinsic rate of increase (how quickly the population grows) and the finite rate of increase (the multiplication factor per generation) both improved significantly. Meanwhile, the mean generation time (how long it takes for one generation to replace the next) decreased, meaning faster population turnover.

Beyond the biological improvements, the new diet reduced production costs by 5.9% compared to the original formula. This cost savings comes from using corn flour—a cheaper ingredient—instead of soybean flour as the primary protein source. While 5.9% might seem small, for large-scale insect farming operations producing millions of insects, this savings adds up quickly. The research also demonstrated that the cost-saving diet didn’t sacrifice quality; in fact, it improved it.

This research builds on existing knowledge that artificial diets can successfully replace natural food sources for mass-rearing insects. Previous studies have shown that diet composition significantly affects insect development and reproduction. This study advances that knowledge by showing that a simple substitution (corn flour for soybean flour) can simultaneously improve biological performance and reduce costs—a rare combination that makes the finding particularly valuable for practical farming applications.

The study was conducted entirely in laboratory conditions with controlled temperature, humidity, and light. Real farms have variable conditions that might affect results differently. The abstract doesn’t specify how many individual insects were tested for each diet, making it difficult to assess the statistical reliability of the findings. Additionally, the research focused specifically on one pest species (tobacco cutworm), so results may not apply equally to other insects. The study also doesn’t address potential long-term effects of the diet on insect genetics or quality over many generations of breeding.

The Bottom Line

Based on this research, farmers and insect-rearing facilities should consider testing the new corn flour-based diet (formulation 15) in their operations. The evidence is strong for laboratory conditions, but implementation should start with small-scale trials to verify results in your specific farm environment. Confidence level: Moderate to High for controlled breeding facilities; Moderate for variable farm conditions.

This research is most relevant for: (1) farmers using biological pest control with parasitoid wasps, (2) commercial insect-rearing facilities, (3) agricultural extension services advising farmers, and (4) pest management companies. It’s less immediately relevant for home gardeners or farmers using chemical pesticides exclusively, though it supports the broader goal of making natural pest control more affordable and accessible.

If you switch to the new diet, you should see faster insect development (2-3 days shorter development time) immediately. Cost savings would be noticeable within the first production cycle. However, to fully assess whether the diet works well in your specific conditions, plan for at least 2-3 complete breeding cycles (several months) of observation and data collection.

Want to Apply This Research?

  • Track weekly: (1) Average development time from egg to adult (in days), (2) Average pupal weight (in milligrams), (3) Number of eggs laid per female, (4) Percentage of eggs that hatch, and (5) Total production cost per 1,000 insects. Compare these metrics before and after switching diets.
  • If using an agricultural app: Log your current diet formula and costs, then create a new entry for the corn flour-based diet. Set reminders to weigh pupae weekly and count eggs daily. Use the app’s comparison feature to track cost savings and development improvements side-by-side over 2-3 breeding cycles.
  • Establish a baseline by tracking your current diet’s performance for one full cycle. Then switch to the new diet and track the same metrics for at least two complete cycles. Use the app to create visual charts showing development time, weight, egg production, and costs. If results match the research findings, gradually scale up production with the new diet while continuing to monitor quality.

This research describes laboratory findings for insect breeding and does not provide medical advice for humans. The study was conducted under controlled conditions that may not reflect real-world farm environments. Before implementing these findings in commercial operations, consult with agricultural extension services or pest management specialists familiar with your local conditions. Results may vary based on factors including temperature fluctuations, humidity levels, diet ingredient quality, and local pest populations. This summary is for informational purposes and should not replace professional agricultural guidance.