Singing Mice and IPM (Integrated Pest Management)

By Dr. Yori Sasaerila

Love me tender, love me dear … is most likely not the tune sung by male mice when in love, but we now know that they can sing when they are in that mood. Timothy E. Holy and Zhougsheng Guo, from Washington University School of Medicine, St. Louis, USA, conducted experiments to find out how male mice respond to the scent of female mouse urine. They found that male mice responded by squeaking. This response, of course, is not a surprise; it has been known for decades that mice squeak. What is surprising about this finding is that when they further analyzed the ultrasonic signals (high-frequency sounds - undetected by human ears), using computerized voice analysis technology, Holy and Guo discovered that they were not just random signals. These ultrasonic signals have two main properties of a song: (1) distinct syllables - recognizable distinct categories of sound, instead of just one sound repeated over and over; and (2) recurring themes - "like the melodic hook in a catchy tune" (Holy and Guo, 2005). In other words, male mice sing in the presence of female mice, a behaviour that so far is only known to a very small group of organisms, including songbirds, humpback whales, porpoises, insects and possibly bats.

This discovery has a significant impact to human beings. For health sciences, this study could be used to help build a model for higher-level tasks such as pattern recognition and hearing in the human brain. This model is essential to developing treatments for autism and other communication disorders. To the pest control industry, it could open an exciting new era. Future Pest Management Professionals may be able to put down mousetraps lured with male-mice song-baited microspeakers.

The baited songs or sounds may vary from songs of virgin females, pregnant females, or even the purring sound of baby mice, or the combination thereof.
From a practical point of view, this finding explains the difficulty in eliminating established rodent infestations. It could also, however, serve as an excellent reminder of the importance of exclusion, sanitation and structural maintenance in an Integrated Pest Management (IPM) program. In food warehouses and/or food plants, for example, this study gives a stronger reason to:

1. keep food in well-sealed containers;
2. remove food that is often found in floor drains, under food preparation equipment, stored products, and around refuse and entry areas;
3. install adequate drainage grates or screens to prevent mouse entry;
4. regularly clean and inspect space under equipment mixers, stoves, counters or refrigerators;
5. look closely at corners and edges of metal or other material covering the insulation for mouse openings; and
6. immediately repair any physical damage to outside doors that are often left ajar due to heavy use.

These points are crucial because when a mouse discovers a food source, it will not only release its pheromone, it will also sing to attract mates. To human ears, the mouse's song might not be as beautiful as those of a songbird, but it certainly is attractive to a female mouse. Once a pair of mice coupled, it's just a matter of time before a new colony will be established. Lastly, the songbirds have been called the Sinatras of the animal world. Should mice be the Presleys?

Reference: Holy TE, Guo Z (2005) Ultrasonic Songs of male mice. PloS Biol 3(12):e386

Garlic Butter Fried Insects

1/4 cup butter
6 cloves garlic, crushed
1 cup cleaned insects*
Melt butter in fry pan. Reduce heat. Sauté garlic in butter for 5 minutes. Add insects. Continue sautéing for 10 - 15 minutes, stirring occasionally.

* Mealworms are especially delicious prepared in this manner.