Richard Mankin, Mentor

Brett Miller using the DAVIS program to analyze acoustic signals generated by rice weevil larvae in wheat grain.

Brett Miller's project involved the acoustic detection of insects (rice weevil and Indian meal moth larvae) infesting stored products (wheat grain and dog food).  He was testing the hypothesis that electrical stimulation from a high voltage prod would encourage insect activity (i.e., movement or feeding).  Increasing the level of activity makes the insects easier to detect by acoustic sensors.

Using the AED-2000 to detect acoustic signals from infested wheat in CMAVE's anechoic chamber.

Wheat grain undergoing electrical stimulation.

Ol' Roy Dinner Rounds undergoing electrical stimulation.

Brett's Abstract:

Effects of Electrical Stimulation on Activity Levels in Plodia interpunctella and Sitophilus oryzae

Plodia interpuntella, more commonly known as the Indian meal moth, is one of the most common pests infesting stored products. It is also one of the most troublesome, as the larvae can feed on a large variety of foods ranging from wheat to chocolate, but especially birdseed and dry dog food. The female moth will lay anywhere from 40 to 400 eggs. Infestations are usually characterized by the presence of adult moths and silken threads spun by the larvae. The meal moth is a big problem for companies which store their packaged food products in warehouses where unsanitary conditions can easily lead to infestations. These infestations then cause damage to food products as well as company reputation if the infested goods are not found and disposed of before they reach the consumer. The current solution to this problem is to randomly select different packages from various locations of the warehouse or storage facility and open them to see if they contain any contaminated material. However, there is still the possibility that infested goods may go undetected, and the ones that are found and destroyed result in a loss of revenue. A better solution to the problem is to listen for sounds that the larvae produce when they are feeding, or moving around in the food. This is done with highly sensitive acoustical sensors that are connected to headphones or a computer equipped with an oscilloscope. The problem with this is that the insects don't always make noise. The president of Hot-Shot Products Co., Bill Bartel, Sr., thought that the electricity produced by the livestock prods his company manufactures might be a means of increasing insect activity, making it easier to detect the insects through the use of acoustical sensors. This project was designed to test this idea. Preliminary tests were conducted on rice weevil (Sitophilus oryzae) larvae but showed no consistent results, so the meal moth became the next test subject. Larvae between the ages of seven and nine days were allowed to infest individual pieces of dry dog food (one larva per piece). Each piece was inspected for activity using a piezo sensor until a piece containing an active larva was found. Then two electrodes fashioned from paperclips were inserted into the dog food, and the dog food was placed on the sensor for recording. The output was recorded for three minutes, then the food was prodded with several short bursts of electricity from the Hot Shot livestock prod. Immediately after this, three more minutes of sound data were recorded and a timer was set for ten minutes. When ten minutes had passed, another three minutes were recorded to see if the activity had dropped off after the initial stimulation. Three sets of twenty tests were done this way. After analyzing with a computer signal analysis program and reviewing the results, it was found that activity levels were generally higher after prodding than before. As a control for effects of handling, another three sets of twenty tests were performed in the same manner, except the electricity was replaced with slight agitation. After analyzing these tests, no consistent increase in activity after agitation was found.