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Measurement of time taken by the Formosan termite, Coptotermes formosanus, to pass tunnel intersections.

Ku SJ, Nan-Yao S, Sang-Hee L - J. Insect Sci. (2012)

Bottom Line: The spent time is likely to be directly connected to the termites' survival because depending on the time, the total traveling time taken by the termites for transferring food resources from the site of food to their nest can vary significantly because of many intersections.For (W(1), W(2) ) = (3, 2), (4, 2), and (4, 4), τ(s) was shorter than τ(R) and τ(R) in each case.The experimental results are briefly discussed in relation to the termite foraging efficiency.

View Article: PubMed Central - PubMed

Affiliation: Division of Forest Resources, College of Forest and Environmental Sciences, Kangwon National University, Kangwon, South Korea.

ABSTRACT
Subterranean termites build complex tunnel networks below ground for foraging. During the foraging activity, termites may encounter a considerable number of tunnel intersections. When they encounter the intersections, they spend some time gathering information for making a decision regarding their moving direction by anntenation. The spent time is likely to be directly connected to the termites' survival because depending on the time, the total traveling time taken by the termites for transferring food resources from the site of food to their nest can vary significantly because of many intersections. In the present study, we measured the time spent by a termite to pass an intersection with widths of W(1) and W(2) (W(1) and W(2) : 2, 3, or 4 mm); τ(L) , τ(R) , and τ(s) are the passing time for turning left, turning right, and going straight, respectively. W(1) represents the width of the tunnel in which the termites advanced, and W(2) represents the width of the other tunnel encountered by the advancing termites. For the combinations of W(1) and W(2), (W(1), W(2) ) = (2, 2), (3, 3), (2, 3), (2, 4), (3, 4), and (4, 3), the values of Tτ(L), τ(R), and τ(s) in each case were statistically equal. For (W(1), W(2) ) = (3, 2), (4, 2), and (4, 4), τ(s) was shorter than τ(R) and τ(R) in each case. The experimental results are briefly discussed in relation to the termite foraging efficiency.

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Photographs showing that an advancing termite is likely to be confronted with the corner of the intersection when it changes its moving direction. High quality figures are available online.
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f03_01: Photographs showing that an advancing termite is likely to be confronted with the corner of the intersection when it changes its moving direction. High quality figures are available online.

Mentions: For arenas in which (W1, W2) = (2, 2) and (3, 3), the values of τL, τR, and τs in each case were statistically the same (see Table 1). This was because the selection of different directions provided no advantage with respect to the tunnel width, and in particular, the narrow intersection area in comparison to the termite body length (∼3 mm) made walking difficult, which in turn diluted the time difference in selecting different directions. However, for (W1, W2) = (4, 4), the value of τSwas significantly smaller than the values of τLand τR, while the values of τL and τR were statistically the same in each case. Most termites moving straight passed the intersection without stopping. In the case that termites advanced from a relatively narrow tunnel to the intersection connecting to wider tunnels ((W1, W2) = (2, 3), (2, 4), and (3, 4)), the values of τL, τR, and τs were statistically the same in each case. For (W1, W2) = (2, 3) and (2, 4), turning into wider tunnels at left or right may have saved time (hence τL, τR < τs), but termites also took more time to change their direction, and during the direction change at the intersection they turned their body vertically and walked on the sidewall (Figure 2). This behavior increased τL and τR, which consequently led to the result τL = τR = τS. For (W1, W2) = (3, 4), many termites turning left or right touched the right—angled corner of the intersection because of the deviation in their walking (Figure 3). As soon as the termites touched the corner, they exhibited the anntenation behavior. This diluted the advantage of the relatively large tunnel width, which consequently led to the statistically equal values of τL, τR, and τs. When the termites advanced from a relatively wide tunnel to the intersection connecting to narrower tunnels ((W1, W2) = (3, 2) and (4, 2)), the value of τs was significantly smaller than the values of τL and τR because of the same reason as the case of (W1, W2) = (4, 4).


Measurement of time taken by the Formosan termite, Coptotermes formosanus, to pass tunnel intersections.

Ku SJ, Nan-Yao S, Sang-Hee L - J. Insect Sci. (2012)

Photographs showing that an advancing termite is likely to be confronted with the corner of the intersection when it changes its moving direction. High quality figures are available online.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472922&req=5

f03_01: Photographs showing that an advancing termite is likely to be confronted with the corner of the intersection when it changes its moving direction. High quality figures are available online.
Mentions: For arenas in which (W1, W2) = (2, 2) and (3, 3), the values of τL, τR, and τs in each case were statistically the same (see Table 1). This was because the selection of different directions provided no advantage with respect to the tunnel width, and in particular, the narrow intersection area in comparison to the termite body length (∼3 mm) made walking difficult, which in turn diluted the time difference in selecting different directions. However, for (W1, W2) = (4, 4), the value of τSwas significantly smaller than the values of τLand τR, while the values of τL and τR were statistically the same in each case. Most termites moving straight passed the intersection without stopping. In the case that termites advanced from a relatively narrow tunnel to the intersection connecting to wider tunnels ((W1, W2) = (2, 3), (2, 4), and (3, 4)), the values of τL, τR, and τs were statistically the same in each case. For (W1, W2) = (2, 3) and (2, 4), turning into wider tunnels at left or right may have saved time (hence τL, τR < τs), but termites also took more time to change their direction, and during the direction change at the intersection they turned their body vertically and walked on the sidewall (Figure 2). This behavior increased τL and τR, which consequently led to the result τL = τR = τS. For (W1, W2) = (3, 4), many termites turning left or right touched the right—angled corner of the intersection because of the deviation in their walking (Figure 3). As soon as the termites touched the corner, they exhibited the anntenation behavior. This diluted the advantage of the relatively large tunnel width, which consequently led to the statistically equal values of τL, τR, and τs. When the termites advanced from a relatively wide tunnel to the intersection connecting to narrower tunnels ((W1, W2) = (3, 2) and (4, 2)), the value of τs was significantly smaller than the values of τL and τR because of the same reason as the case of (W1, W2) = (4, 4).

Bottom Line: The spent time is likely to be directly connected to the termites' survival because depending on the time, the total traveling time taken by the termites for transferring food resources from the site of food to their nest can vary significantly because of many intersections.For (W(1), W(2) ) = (3, 2), (4, 2), and (4, 4), τ(s) was shorter than τ(R) and τ(R) in each case.The experimental results are briefly discussed in relation to the termite foraging efficiency.

View Article: PubMed Central - PubMed

Affiliation: Division of Forest Resources, College of Forest and Environmental Sciences, Kangwon National University, Kangwon, South Korea.

ABSTRACT
Subterranean termites build complex tunnel networks below ground for foraging. During the foraging activity, termites may encounter a considerable number of tunnel intersections. When they encounter the intersections, they spend some time gathering information for making a decision regarding their moving direction by anntenation. The spent time is likely to be directly connected to the termites' survival because depending on the time, the total traveling time taken by the termites for transferring food resources from the site of food to their nest can vary significantly because of many intersections. In the present study, we measured the time spent by a termite to pass an intersection with widths of W(1) and W(2) (W(1) and W(2) : 2, 3, or 4 mm); τ(L) , τ(R) , and τ(s) are the passing time for turning left, turning right, and going straight, respectively. W(1) represents the width of the tunnel in which the termites advanced, and W(2) represents the width of the other tunnel encountered by the advancing termites. For the combinations of W(1) and W(2), (W(1), W(2) ) = (2, 2), (3, 3), (2, 3), (2, 4), (3, 4), and (4, 3), the values of Tτ(L), τ(R), and τ(s) in each case were statistically equal. For (W(1), W(2) ) = (3, 2), (4, 2), and (4, 4), τ(s) was shorter than τ(R) and τ(R) in each case. The experimental results are briefly discussed in relation to the termite foraging efficiency.

Show MeSH