A Novel Strain of Steinernema riobrave (Rhabditida: Steinernematidae) Possesses Superior Virulence to Subterranean Termites (Isoptera: Rhinotermitidae)

Subterranean termites are major global pests of wood structures and wood products. Among the most economically important subterranean termite species in the US are Heterotermes aureus, Reticulitermes flavipes, and Coptotermes formosanus. In prior studies, the entomopathogenic nematode, Steinernema riobrave strain 355, exhibited a high level of virulence to H. aureus compared with other nematode species. However, S. riobrave 355 was reported to be poorly or only moderately virulent to R. flavipes and C. formosanus, respectively. We hypothesized that other strains of S. riobrave may possess a high level of virulence to all three termite species. Under laboratory conditions we compared three novel strains of S. riobrave (3-8b, 7-12, and TP) with the 355 strain for virulence to H. aureus, R. flavipes, and C. formosanus workers. H. aureus was very susceptible to all the S. riobrave strains, and termites in all nematode treatments were dead after 4 d. The TP strain of S. riobrave caused greater mortality in R. flavipes and C. formosanus compared to the other nematode strains. Specifically, the TP strain caused 75% and 91% mortality in R. flavipes and C. formosanus, respectively, which was more than 300% and 70% higher than the mortality caused by other strains. Additional studies are warranted to determine the ability of S. riobrave (TP) to control the targeted termite species under field conditions.     

Tunnel formation by Reticulitermes flavipes and Coptotermes formosanus (Isoptera: Rhinotermitidae) in response to wood in sand.

The tunneling responses of two subterranean termite species, Coptotermes formosanus Shiraki and Reticulitermes flavipes (Kollar), to the presence of sound wood in laboratory arenas were studied. Branching pattern and the speed of tunnel construction between R. flavipes and C. formosanus also were compared. Patlak's residence index (rho) was generated using the length, width, speed of construction, and area of the primary tunnels built by termites. In the same allotted time, C. formosanus built wider and shorter primary tunnels, whereas R. flavipes built thinner and longer primary tunnels. The presence of wood did not affect termite tunnel formation. This lack of variation in tunnel formation parameters was evidenced by the inability of the termites to locate wood sources over distance, even as short as 2.5 mm, and by the similar tunneling behaviors in areas of the arena with or without wood. Patlak's model predicted the densities of tunnels with an error between 9 and 28%. in experiments with R. flavipes exposed to a range of 0-8,000 g of wood, and between 61 and 87% in experiments with C. formosanus. These results indicated that the residence index can provide a qualitative measure of the effect of habitat heterogeneity on the individual termite tunnels. The tunneling constructions strategy of these subterranean termites is discussed.     

Behavioral Interactions Between <Emphasis Type="Italic">Aphaenogaster rudis</Emphasis> (Hymenoptera: Formicidae) and <Emphasis Type="Italic">Reticulitermes flavipes</Emphasis> (Isoptera: Rhinotermitidae): The Importance of Physical Barriers

Predation pressure from ants is a major driving force in the adaptive evolution of termite defense strategies and termites have evolved elaborate chemical and physical defenses to protect themselves against ants. We examined predator–prey interactions between the woodland ant, Aphaenogaster rudis (Emery) and the eastern subterranean termite, Reticulitermes flavipes (Kollar), two sympatric species widely distributed throughout deciduous forests in eastern North America. To examine the behavioral interactions between A. rudis and R. flavipes we used a series of laboratory behavioral assays and predation experiments where A. rudis and R. flavipes could interact individually or in groups. One-on-one aggression tests revealed that R. flavipes are vulnerable to predation by A. rudis when individual termite workers or soldiers are exposed to ant attacks in open dishes and 100% of termite workers and soldiers died, even though the soldiers were significantly more aggressive towards the ants. The results of predation experiments where larger ant and termite colony fragments interacted provide experimental evidence for the importance of physical barriers for termite colony defense. In experiments where the termites nested within artificial nests (sand-filled containers), A. rudis was aggressive at invading termite nests and inflicted 100% mortality on the termites. In contrast, termite mortality was comparable to controls when termite colonies nested in natural nests comprised of wood blocks. Our results highlight the importance of physical barriers in termite colony defense and suggest that under natural field conditions termites may be less susceptible to attacks by ants when they nest in solid wood, which may offer more structural protection than sand alone.     

Behavioral responses of two subterranean termite species (Isoptera: Rhinotermitidae) to instant freezing or chilling temperatures

The behavioral responses to instant freezing or chilling temperatures and survivorship of the Formosan subterranean termite, Coptotermes formosanus Shiraki, and the Eastern subterranean termite, Reticulitermes flavipes (Kollar), were studied using a novel experimental design that closely simulated subterranean termites' natural in-ground environment. Both termite species responded to changes in temperature by exhibiting a downward mass movement from the cold to warmer area of constant temperature. However, the degrees of response were specific to the species and temperature regimen. Approximately 88 and 96% of R. flavipes escaped from instant 0 degrees C and chilling regimens (from 24 to 0 degrees C at a rate of 1 degrees C/h or 1 degrees C/12 h), respectively, compared with approximately 77 and 91% of C. formosanus. No significant difference was detected between the two cooling regimens in either termite species. Controls resulted in a relatively even distribution within test tubes in both termite species. The small portion of the termites that did not escape endured a cold coma at a 24-h 0 degrees C and had low mortality of 2.2 and <1% in R. flavipes and <5.2 and <3% in C. formosanus at instant and chilling regimens, respectively. This result may have implications for understanding group intelligence and decision making evolved by subterranean termites to survive temporary freezing cold.     

Tunneling and mortality of eastern and Formosan subterranean termites (Isoptera: Rhinotermitidae) in sand treated with thiamethoxam or fipronil

Thiamethoxam and fipronil were examined for their termiticidal properties against the Formosan subterranean termite, Coptotermes formosanus Shiraki, and the eastern subterranean termite, Reticulitermes flavipes (Kollar). Concentrations > or =8 ppm thiamethoxam and > or =1 ppm fipronil provided an effective barrier against C. formosanus and R. flavipes. Sand was penetrated to some degree at all concentrations of thiamethoxam (0-800 ppm for C. formosanus and 0-1000 ppm for R. flavipes) and fipronil (0-64 ppm for both C. formosanus and R. flavipes) tested, indicating that both termiticides are nonrepellent. Thiamethoxam was found to be more toxic against C. formosanus than R. flavipes whereas fipronil showed similar toxicity for both species. Higher mortality prevented termites from penetrating the entire 5-cm segment of treated sand.     

Agonistic behavior among colonies of the Formosan subterranean termite,Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), from Florida and Hawaii: Lack of correlation with cuticular hydrocarbon composition

Cuticular hydrocarbon patterns of the Formosan subterranean termite, Coptotermes formosanus Shiraki, were similar among colonies from the same geographical location. Hydrocarbon patterns of Florida colonies were easily distinguished from those of Hawaii colonies by using canonical discriminant analysis. Groups of termites from the same colony did not fight one another when placed in an arena. Intercolonial aggression was not recorded among C. formosanuspopulations from Florida but three colonies from Hawaii fought with the other Hawaiian and three Florida colonies. Of the 12 colonies (six each from Florida and Hawaii) tested, 3 Florida colonies did not direct or receive aggression from any other colony. Cuticular hydrocarbon patterns were not correlated with agonistic behavior.     

Wood excavations of three species of subterranean termites

We compared the feeding excavations on wood blocks of three species of subterranean termites, Coptotermes formosanus Shiraki, Reticulitermes flavipes (Kollar), and R. virginicus (Banks). Feeding rate followed the order C. formosanus > R. flavipes > R. virginicus. Wood surface area (mm²) exposed per unit feeding was higher for C. formosanus and R. flavipes than for R. virginicus. This was caused by the tendency of C. formosanus and R. flavipes to make internally penetrating tunnels, thereby increasing surface area, whereas R. virginicus made trough- and bowl-like depressions on the outside of blocks, sometimes decreasing the size of blocks outwardly without a corresponding high increase in surface area typical with the tunnels of the other species. Consequently, wood surface area was sometimes reduced, rather than increased as a result of feeding by R. virginicus. Different patterns of wood excavation suggest that these termites have divergent roles in wood decay processes.

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Résumé Les organismes pionniers qui modifient le bois et le rendent acceptable par les insectes qui le perforent sont généralement des champignons du bois pourri. Cependant, une fois que les termites ou autres insectes perforant le bois ont pénétré, leurs galeries favorisent les bactéries fixatrices d'azote, permettent l'invasion d'autres organismes décomposeurs, et de ce fait régularisent la décomposition du bois (Ausmus, 1977). L'exposition de la surface à l'intérieur des perforations jouant un rôle très important dans le processus de pourrissement, il est souhaitable de pouvoir quantifier la surface des galeries dues à l'alimentation des termites. Une courbe type permettant de prédire l'aire de la surface perforée a été construite en perçant 109 morceaux de bois de trous cylindriques de différents diamètres, en calculant l'aire de la surface des morceaux de bois, en appliquant et pesant une couche de vernis pour bois au polyuréthane, et en divisant la masse de polyuréthane par l'aire de la surface. Le modèle prédictif qui en découle est: Y=0,01443×-3,51825 (P=0,0001; r=0,68), y étant la masse de polyuréthane (en g) et x la surface (en mm²) du morceau de bois. En traitant de la même façon au polyuréthane les morceaux de bois perforés par les termites, nous pourrions déduire leur surface.Une expérience a été effectuée avec 3 espèces de rhinotermitides,- Coptotermes formosanus Shiraki, Reticulitermes flavipes (Kollar) et R. virginicus (Banks). Des groupes de chaque espèce se sont alimentés pendant 11 ou 12 jours sur des morceaux de bois non contaminés par des champignons. Nous avons déterminé la survie, la consommation, la modification de la surface du morceau de bois (par utilisation du modèle prédictif) et le changement de surface par terminte.La survie est la même, mais la consommation est dans l'ordre suivant: C. formosanus > R. flavipes > R. virginicus. L'aire de la surface exposée par unité d'alimentation était plus élevée pour C. formosanus et R. flavipes que pour R. virginicus (Tab. 1). Ceci est dû à la tendance de C. formosanus et R. flavipes de creuser des galeries vers l'intérieur, tandis que R. virginicus fait des cuvettes à la surface du bois. Les attaques superficielles de R. virginicus réduisent parfois le volume du morceau de bois sans accroître proportionnellement la surface comme le font les espèces creusant des galeries. Ainsi, avec R. virginicus la surface peut être réduite au lieu d'augmenter. Des différences entre colonies s'observent avec toutes les variables (Tab. 2).Nos résultats suggèrent que C. formosanus et R. flavipes contribuent plus que R. virginicus à exposer le bois aux autres organismes décomposeurs. Cependant, ces résultats peuvent être modifiés par un conditionnement préalable du bois par des champignons.

     

Interspecific Interactions Between Coptotermes formosanus and Reticulitermes flavipes (Isoptera: Rhinotermitidae) in Laboratory Bioassays

Experiments were conducted to examine competitive interactions between the Formosan subterranean termite, Coptotermes formosanus Shiraki (FST), and the eastern subterranean termite, Reticulitermes flavipes (Kollar) (EST), using groups of termites with different worker:soldier proportions. Experiments were conducted using three connected test chambers: an FST chamber, an unoccupied center chamber, and an EST chamber. When groups of FST were comprised of 20% soldiers versus 2% EST soldiers, only 8% of center chambers were occupied exclusively by EST. When groups of FST were comprised of 10% soldiers versus 1% EST soldiers, 44% of center chambers were occupied exclusively by EST. When the only food source was located in the center chamber, 60% of center chambers were occupied by both species. FST did not completely displace EST in any of these experiments.     

Diversity of Gut Bacteria of <Emphasis Type="Italic">Reticulitermes flavipes</Emphasis> as Examined by 16S rRNA Gene Sequencing and Amplified rDNA Restriction Analysis

The phylogenetic species richness of the bacteria in the gut of the termite Reticulitermes flavipes was examined using near full-length 16S rRNA gene sequencing and amplified rDNA restriction analysis (ARDRA). We amplified the genes by polymerase chain reaction (PCR) directly from a mixed population of termite gut bacteria and isolated them using cloning techniques. Sequence analysis of 42 clones identified a broad taxonomic range of ribotypes from six phyla within the domain Bacteria: Proteobacteria, Spirochaetes, Bacteroidetes, Firmicutes, Actinobacteria, and the recently proposed “Endomicrobia.” Analysis of the sequence data suggested the presence of a termite specific bacterial lineage within Bacteroidetes. The ARDRA data included 261 different ARDRA profiles of 512 clones analyzed. These data suggest the gut flora in R. flavipes is extremely diverse.     

Toxicity of seven termiticides on the formosan and eastern subterranean termites

Using both topical application and substrate (sand) treatments the toxicities of seven new generation soil termiticides were evaluated to determine the LD50 and LC50 against two economically important subterranean termite species, eastern subterranean termite, Reticulitermes flavipes (Kollar), and Formosan subterranean termite, Coptotermes formosanus Shiraki. The lethal dose toxicity (LD50) rankings for R. flavipes from highest to lowest were: fipronil > bifenthrin > chlorantraniliprole > cyantraniliprole > imidacloprid > chlorfenapyr > indoxacarb; the rankings for C. formosanus were fipronil > imidacloprid > chlorantraniliprole > cyanthraniliprole> bifenthrin > chlorfenapyr > indoxacarb. The respective lethal concentration toxicity (LC50) rankings were fipronil > bifenthrin > chlorfenapyr > indoxacarb > cyantraniliprole > chlorantraniliprole > imidacloprid for R. flavipes; and fipronil > chlorfenapyr > bifenthrin >imidacloprid > cyantraniliprole > chlorantraniliprole > indoxacarb for C. formosanus. The study provides an opportunity to directly compare toxicity, action speed, and bioavailability among this group of newer generation soil termiticides.     

A novel approach to characterize branching network: Application to termite tunnel patterns

We defined a novel “branch length similarity” (BLS) entropy, S, on a simple network consisting of a single node and branches. This simple network is referred to as “unit branching network” (UBN) because UBNs are components of larger networks. As an application of BLS entropy, we considered the characterization of termite tunnel patterns because termite tunnel patterns can be broken down into a collection of simple units consisting of a single node and branches. These simple units correspond to UBNs. To this end, in additional to the entropy, we introduced the standard deviation (σ) of the difference in S between UBNs connected by a single tunnel branch. Forty simulated tunnel patterns were created for each of two termite species, Reticulitermes flavipes (Kollar) and Coptotermes formosanus Shiraki. These patterns were projected into <S>–σ phase space in order to assess their topological properties. This approach showed that for R. flavipes, their coordinates were relatively more clustered than those of C. formosanus. This result reflected that these two species were differently constrained by emergent property resulting from simple worker's tunneling behavior. We believe that the approach proposed in this study can be a useful tool to explore termite tunnel systems, but not limited to termite system.     

Time trends in mortality for thiamethoxam and fipronil against Formosan subterranean termites and eastern subterranean termites (Isoptera: Rhinotermitidae)

Time trends in mortality for the Formosan subterranean termite, Coptotermes formosanus Shiraki, and eastern subterranean termite, Reticulitermes flavipes (Kollar), were determined for thiamethoxam and fipronil. Filter paper treated with 50 ppm thiamethoxam led to >80% mortality in 2-4 d for R. flavipes, whereas 5 ppm thiamethoxam resulted in >80% mortality in 2-3 d for C. formosanus. Filter paper treated with 1 ppm fipronil resulted in >80% mortality in 5 d for R. flavipes and 9 d for C. formosanus, indicating that thiamethoxam is faster acting than fipronil. As concentration decreases for slow-acting termiticides, the time required for adverse effects to be fully expressed increases.     

Antitermitic effect of the Lantana camara plant on subterranean termites (Isoptera: Rhinotermitidae)

Abstract The insecticidal effects of Lantana camara L. (flowers, leaves, stems and roots) and the soil where lantana had been growing, on foraging activity and survival of the subterranean termites Coptotermes formosanus and Reticulitermes flavipes were examined in a 3-week experiment. The soil in which lantana had been growing had no effect on termite tunneling and survival. Incorporation of chipped fresh lantana leaves and stems into soil had no effect on mortality but caused significant reduction in tunneling. The 5-cm wide barrier of soil with lantana tissue incorporated effectively repelled groups of both species from penetrating the barrier and thus prevented infestation of a piece of wood on the other side of the barrier. C. formosanus was more sensitive in avoiding the barrier than R. flavipes. Leaves, stems and flowers were more repellent than roots. These results provide preliminary evidence that fresh-cut lantana leaves, stems and flowers may have use as additives to garden mulches against termites.     

两种鼻白蚁之间的入侵关系

设计了5个实验以研究台湾乳白蚁(Coptotermes formosanus)和黄肢散白蚁(Reticulitermes flavipes)的种间斗争关系。所试白蚁来自阿拉巴马州。实验1将两组白蚁的兵蚁和工蚁以自然比例混合(台湾乳白蚁工蚁：兵蚁＝20：5,黄肢散白蚁工蚁：兵蚁＝24：1);实验2观察了双方同数量(各25头)工蚁的种间斗争能力;实验3观察两者同数量(各5头)兵蚁的种间斗争关系;实验4、5分别研究双方工蚁与兵蚁的斗争关系。因两种工蚁形态相似,所以在实验前用0．1％Nile blue A染过的滤纸饲喂一方白蚁24h使虫体着色以便观察。所有实验在22℃,65％RH荧光灯下进行。每个实验将两方白蚁同时放入一培养皿中,观察至一方100％受伤,然后把培养皿移到培养箱内,24小时后统计死亡率。结果表明,实验一开始,双方的工蚁和兵蚁都立即进入残酷的厮杀斗争,台湾乳白蚁兵蚁和工蚁的斗争能力都明显强于黄肢散白蚁;兵蚁的斗争行为不受工蚁的影响,工蚁的斗争能力也不受兵蚁的制约。实验中台湾乳白蚁的工蚁与黄肢散白蚁的兵蚁攻击能力相当,但黄肢散白蚁的工蚁却远弱于台湾乳白蚁的兵蚁。上述结果说明,自然界中不可能出现此两种白蚁群体的偶然性融合;外来的台湾乳白蚁很可能在其群体建立的地区占据优势[动物学报49(3)：295—302,2003]。     

Volatile Fatty Acid Production by the Hindgut Microbiota of Xylophagous Termites

Acetate dominated the extracellular pool of volatile fatty acids (VFAs) in the hindgut fluid of Reticulitermes flavipes, Zootermopsis angusticollis, and Incisitermes schwarzi, where it occurred at concentrations of 57.9 to 80.6 mM and accounted for 94 to 98 mol% of all VFAs. Small amounts of C₃ to C₅ VFAs were also observed. Acetate was also the major VFA in hindgut homogenates of Schedorhinotermes lamanianus, Prorhinotermes simplex, Coptotermes formosanus, and Nasutitermes corniger. Estimates of in situ acetogenesis by the hindgut microbiota of R. flavipes (20.2 to 43.3 nmol · termite⁻¹ · h⁻¹) revealed that this activity could support 77 to 100% of the respiratory requirements of the termite (51.6 to 63.6 nmol of O₂ · termite⁻¹ · h⁻¹). This conclusion was buttressed by the demonstration of acetate in R. flavipes hemolymph (at 9.0 to 11.6 mM), but not in feces, and by the ability of termite tissues to readily oxidize acetate to CO₂. About 85% of the acetate produced by the hindgut microbiota was derived from cellulose C; the remainder was derived from hemicellulose C. Selective removal of major groups of microbes from the hindgut of R. flavipes indicated that protozoa were primarily responsible for acetogenesis but that bacteria also functioned in this capacity. H₂ and CH₄ were evolved by R. flavipes (usually about 0.4 nmol · termite⁻¹ · h⁻¹), but these compounds represented a minor fate of electrons derived from wood dissimilation within R. flavipes. A working model is proposed for symbiotic wood polysaccharide degradation in R. flavipes, and the possible roles of individual gut microbes, including CO₂-reducing acetogenic bacteria, are discussed.     

Protein marking reveals predation on termites by the woodland ant, <Emphasis Type="Italic">Aphaenogaster rudis</Emphasis>

Subterranean termites provide a major potential food source for forest-dwelling ants, yet the interactions between ants and termites are seldom investigated largely due to the cryptic nature of both the predator and the prey. We used protein marking (rabbit immunoglobin protein, IgG) and double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) to examine the trophic interactions between the woodland ant, Aphaenogaster rudis (Emery) and the eastern subterranean termite, Reticulitermes flavipes (Kollar). We marked the prey by feeding the termites paper treated with a solution of rabbit immunoglobin protein (IgG). Subsequently, we offered live, IgG-fed termites to ant colonies and monitored the intracolony distribution of IgG-marked prey. Laboratory experiments on the distribution of protein-marked termite prey in colonies of A. rudis revealed that all castes and developmental stages receive termite prey within 24 h. In field experiments, live, protein-marked termites were offered to foraging ants. Following predation, the marker was recovered from the ants, demonstrating that A. rudis preys on R. flavipes under field conditions. Our results provide a unique picture of the trophic-level interactions between predatory ants and subterranean termites. Furthermore, we show that protein markers are highly suitable to track trophic interactions between predators and prey, especially when observing elusive animals with cryptic food-web ecology. Received 19 January 2007; revised 23 March 2007; accepted 26 March 2007.     

Resistance of insecticide-treated foam board insulation against the eastern subterranean termite and the Formosan subterranean termite (Isoptera: Rhinotermitidae)

Three foam board types, one untreated control, one containing 2,000 ppm disodium octaborate tetrahydrate (DOT), and one containing 1,000 ppm deltamethrin, were exposed to field populations of the eastern subterranean termite, Reticulitermes flavipes (Kollar), and the Formosan subterranean termite, Coptotermes formosanus Shiraki. There was no significant difference in termite damage between foam boards treated with 2,000 ppm DOT and the untreated control. Form boards containing 1,000 ppm deltamethrin were not damaged by R. flavipes, whereas only minor damage occurred after exposure to C. formosanus.     

In situ morphology of the gut microbiota of wood-eating termites [Reticulitermes flavipes (Kollar) and Coptotermes formosanus Shiraki].

Light microscopy and scanning and transmission electron microscopy were used to examine the in situ morphology of the gut microbiota of Reticulitermes flavipes and Caoptotermes formosanus. Laboratory-maintained termites were used and, for R. flavipes, specimens were also prepared immediately after collection from a natural infestation. The latter endeavor enabled a study of different castes and developmental stages of R. flavipes and revealed differences in the microbiota of field versus laboratory specimens. The termite paunch microbiota consisted of an abundance of morphologically diverse bacteria and protozoa. Thirteen bacterial morphotypes in the paunch were described in detail: seven were observed only in R. flavipes, three were observed only in C. formosanus, and three were common to both termite species. The paunch epithelium was densely colonized by bacteria, many of which possessed holdfast elements that secured them tightly to this tissue and to other bacterial cells. Besides bacteria, the protozoan Pyrsonympha vertens adhered to the paunch epithelium of R. flavipes by means of an attachment organelle. Cuplike indentations were present on the paunch epithelial surface and were sites of bacterial aggregation. Ultrastructural features of cups suggested their involvement in ion absorption. In addition to the paunch, the midgut was also colonized by bacteria that were situated between epithelial microvilli. Results suggest that bacteria are an integral part of the gut ecosystem.     

The influence of branching tunnels on subterranean termites' foraging efficiency: Considerations for simulations

In our previous study, we constructed a lattice model of termite tunnel pattern to explore the relationship between tunnel geometry and foraging efficiency. The model was based on experimental data obtained from homogeneous soil substrates without food resource. In the present study, we adopted a more general rule in the model to determine branching tunnel lengths. The rule was described by two variables, the probability of tunnel branching, P_branch, and the probability for a branching tunnel to terminate, P_term. With the modified model, we explored the influence of the geometry of branching tunnel on foraging efficiency, γ, for two termite species, Coptotermes formosanus and Reticulitermes flavipes (Isoptera: Rhinotermitidae). For C. formosanus, γ map consisting of the two variables were partitioned in three regions by the level of γ value, while γ for R. flavipes was categorized as two regions: higher γ and lower γ. This result was discussed in termite foraging strategy.     

Tunneling activity of subterranean termites (Isoptera: Rhinotermitidae) in sand with moisture gradients

Tunnel formation by Coptotermes formosanus and Reticulitermes flavipes was studied in a two-dimensional foraging arena with a moisture gradient. Moisture did not appear to affect tunneling when termite first emerged from the central release chamber. But as termites of both species moved further away from the chamber and into a moisture gradient, they tunneled significantly (P < 0.05) more in sand with a higher moisture content than in sand with a lower moisture content. Over the 10 d test period, both termite species tunneled more in sand with a higher moisture content. Fractal analysis indicated that regardless of the sand moisture content, termite tunnel geometry had a fractal dimension and termites generally tunneled more in higher moisture sand.