Do Tunnel Patterns of Coptotermes formosanus and Coptotermes gestroi (Blattodea: Rhinotermitidae) Reflect Different Foraging Strategies?

Abstract

Tunnel network construction and time to food (wood) discovery by Coptotermes formosanus Shiraki and Coptotermes gestroi (Wasmann) (Blattodea: Rhinotermitidae) (formerly known as Coptotermes vastator Light in the Pacific region) was examined when wood was present in a clumped distribution that mimics field conditions in the subtropical and temperate regions where C. formosanus naturally occurs. Previous research has noted that the tropical species C. gestroi constructs a highly branched tunnel network, while the subtropical C. formosanus constructs longer tunnels with few branches. Grace et al. (2004) hypothesized that this difference in tunneling behavior may relate to a more homogenous distribution of woody resources in the tropics vs. a disjunct and clumped distribution of fallen wood in the cooler subtropics. Thus, C. gestroi may exhibit a thorough search of the immediate area where wood is initially located, while it may be more energetically efficient for C. formosanus to tunnel greater distances in search of scattered resources. To test this hypothesis, we placed two wood resources at the opposite ends of laboratory foraging arenas, and released 1500 termites (1350 workers: 150 soldiers) into each arena. Arenas were observed every 24 hours for 14 days. We measured the total daily tunnel length, number of tunnels created in each quadrant of the arenas, and average time to discover food at both ends. Total daily tunnel length was relatively longer with C. formosanus and average time to discover food at either end was longer for C. gestroi. Although replication was limited in this study, these observations lend support to the hypothesis that C. formosanus is able to locate distant resources more efficiently than C. gestroi.

Assessment of Genetic Markers for the Determination ofCoptotermes formosanus×Coptotermes gestroi(Isoptera: Rhinotermitidae) F1 Hybrids

“…Even if the two termite species did not differ in the time taken to find the first piece of wood, which was possible since the arenas were fairly small, the longer and straighter tunnels constructed by C. formosanus would be expected to give it an advantage in discovering the second piece of wood at the opposite end of the arena, since C. gestroi would be expected to construct a dense network of tunnels around the first piece of wood discovered rather than immediately striking out across the arena. As predicted, C. formosanus did indeed locate the first piece of wood in the arenas an average of one day faster than C. gestroi (2.5 vs. 3.5 days), and then discovered the second piece of wood at the opposite end of the arena an average of 2.5 days faster as well (6 vs. 8.5 days) (Hapukotuwa and Grace 2012c). Yeoh and Lee (2007) also observed that the dense and heavily branched tunneling networks of C. gestroi and C. curvignathus Homgren contrasted with the straight and relatively unbranched tunnels of C. kalshoveni Kemner.…”

Foraging in subterranean termites (Isoptera: Rhinotermitidae): how do Heterotermes tenuis and Coptotermes gestroi behave when they locate equivalent food resources?

“…Nevertheless, in the present study, the multiple-choice tests showed that H. tenuis and C. gestroi display the same behavioral patterns in relation to the consumption and the recruitment of foragers for equivalent food sources, and these facts suggest that subterranean termites did not concentrate their efforts on the consumption of only one food when multiple resources are available. Hapukotuwa & Grace (2012) verified that C. gestroi continues to shift from one food source to another, rather than remaining until each food resource is consumed, confirming the idea that this species does not display a chronological priority in relation to the location of food.…”

Influence of Soldiers on Exploratory Foraging Behavior in the Formosan Subterranean Termite, Coptotermes formosanus (Blattodea: Rhinotermitidae)

“…Additionally, C. formosanus colonies built shorter and wider primary tunnels compared to R. flavipes [ 48 ]. It is proposed that the differences in foraging strategy are partly dependent on resource abundance in the native range of the species, with longer and less branched tunnels associated with clumped and heterogeneous resources, and short and highly branched tunnels efficient for locating homogenously distributed resources [ 49 ]. The ecological drivers of different foraging strategies require further investigation in subterranean termite species.…”