Why Old Comb Is Holding Your Hive Back: New Study Backs the Case for Fresh Wax

A new 2025 study out of the University of Sulaimani has delivered a clear message for beekeepers: if you’re not regularly replacing your old comb, you’re likely sacrificing brood health, worker productivity, and honey yields. The research strongly supports what I’ve previously outlined in my blog post “The Hidden Danger in Your Hive: How Contaminated Beeswax Can Undermine Bee Health and Productivity.” There is more supporting scientific evidence in and it’s unambiguous.

Researchers compared colonies housed on old wax combs (3+ years) to those with fresh foundation over three seasons. Colonies with new comb consistently outperformed those with old comb across all key metrics:

• Brood area: New comb colonies had significantly larger sealed and unsealed brood areas.

• Food storage: These colonies stored more honey and pollen, especially during spring and summer.

• Bee size: Worker bees reared in new comb were measurably larger, with wider abdomens and longer bodies.

  
  

The study confirms that old comb becomes physically restrictive. Over time, larval silk and propolis buildup shrink cell sizes, stunting worker development and reducing storage capacity. This means fewer and smaller bees and less honey.

The common argument against comb replacement is cost, particularly in commercial operations. But this study adds weight to the idea that not replacing the comb is a false economy. The loss in colony performance, honey yield, and bee health could easily outweigh the savings.

For New Zealand beekeepers—especially those managing Mānuka production—this research reinforces the importance of strategic comb rotation as part of your annual management plan. Not only does it reduce contamination and pathogen load, but it also directly improves colony performance.

Takeaway:

If your hives are running on dark, old combs, you’re likely leaving productivity on the table. This new research confirms what many have suspected: fresh comb makes stronger, more efficient hives. Your bees and your bottom line will thank you.

Read the study here: https://jam.utq.edu.iq/index.php/main/article/view/452