Laboratory Study of the Influence of Substrate Type and Temperature on the Exploratory Tunneling by Formosan Subterranean Termite.

Bal K Gautam,Gregg Henderson

doi:10.3390/insects3030629

Abstract

Using two-dimensional foraging arenas, laboratory tests were conducted to investigate the effect of soil type, soil moisture level and ambient temperature on the exploratory tunneling by Coptotermes formosanus Shiraki. In choice arenas consisting of two substrate types having two moisture levels each, and conducted at a constant temperature of 22 °C, a significantly greater proportion of termites aggregated in sand than in sandy loam. Similarly, the length of excavated tunnels was also increased in sand. In a given substrate, termite aggregation or tunnel length did not differ between 5% and 15% moisture levels. In no-choice tests, where three different substrates (sand, sandy loam and silt loam) were tested at two temperatures (22 °C and 28 °C), excavations were significantly greater in sand than either sandy loam or silt loam at 22 °C. Fewer primary tunnels were constructed in sandy loam than in sand and fewer branched tunnels than either in sand or silt loam. No significant difference in either tunnel length or number of primary or branched tunnels was found between these two temperatures.

Highlights

Subterranean termites search for food by constructing a ramified tunnel and gallery system underneath and above the soil
After 24 h, a significantly greater proportion of released termites were recovered in sand than in the sandy loam (F = 325.37; df = 1, 16; p < 0.0001) but the tested moisture levels had no significant impact on the number of termites found on a given substrate type (F = 0.69; df = 1, 16; p = 0.43) and had no interaction effect of the substrate and moisture levels (F = 0.88; df = 1, 16; p = 0.36) (Figure 1)
Understanding the role of substrate types, moisture levels and temperatures on the search tunnel formation by subterranean termites is important to optimizing the control strategies

Summary

Introduction

Subterranean termites search for food by constructing a ramified tunnel and gallery system underneath and above the soil. The presence and amount of food have been reported to influence the branching and total length of tunnel system constructed by subterranean termites such as C. formosanus [1] and Reticulitermes santonensis De Feytaud [12]. There are studies [13,14] which suggest that food search by C. formosanus is systematic and not affected by food in the foraging arena. These studies agree that the main and branched tunnels are organized in a way that they avoid searching the area that was already explored

Objectives

Results

Conclusion