[Show abstract][Hide abstract]ABSTRACT: This study investigated age polyethism and the frequencies of behaviors in relation to the distance from the egg cluster in nests of Coptotermes formosanus Shiraki, a lower termite. Juvenile colonies of C. formosanus were introduced in planar arenas and termite activity was recorded with camcorders. The results showed that there were differences in distribution of caste/instar between the royal chamber and the secondary feeding site. There was a gradient of termite distribution within the vicinity of the royal chamber, with the egg cluster as the center. A negative correlation between the number of behavioral events per individual and distance of the behavioral event from the egg cluster was found for many behaviors. However, some behaviors were positively correlated with the distance from the egg clusters in the royal chamber, implying that not all behavior frequencies were termite density dependent. Finally, most motionless termites were found near the royal chamber, presumably about to molt or recently molted. Our study confirmed the occurrence of age polyethism in C. formosanus and there was heterogeneous distribution of caste/instar and behaviors away from the egg clusters. Task division was not only instar dependent but also location dependent, although behavioral compartmentalization was not as distinct as found in higher termites. This observation suggests that the complexity of age polyethism in Coptotermes is intermediate between lower termites and higher termites, as a case of evolutionary step.
Full-text available · Article · Nov 2016 · Insectes Sociaux
[Show abstract][Hide abstract]ABSTRACT: Molt frequency of workers in laboratory-reared juvenile colonies and foraging population from field colonies of Coptotermes formosanus Shiraki was determined using planar arenas in laboratory. Given that, chitin synthesis inhibitor (CSI)-incorporated baits disrupt the molting process of workers that comprises the major population of a termite colony, temporal assessment of molting frequency in workers can give insights into potential methods of reducing the time to eliminate a CSI-baited colony. In our study the 10-d observation of juvenile colonies of C. formosanus suggested average daily molting incidence of workers in a colony is 1.7 ± 0.3% (mean ± SD). The results from a time lapse study on foraging population of workers showed that on average there is a 44-d intermolt period for second-instar workers molting to third instar and 45 d for third-instar workers molting to fourth instar. At low temperature (21 °C), molting frequency of workers (0.6% per day) was significantly lower than that of workers at 27 °C (2.2% per day). Information from this study suggests that time to molt is an important component of total time for eliminating colonies treated with CSI baits and reduction in time lapse between two consecutive molts may reduce the time required for colony elimination.
Full-text available · Article · Aug 2016 · Journal of Economic Entomology
[Show abstract][Hide abstract]ABSTRACT: Juvenile colonies of Coptotermes formosanus Shiraki were investigated to determine the social interactions among all individuals near the central nest of a colony. The behavioral repertoire of whole colonies of subterranean termites has yet to be identified because of their cryptic nests. Colonies were placed in planar arenas, and their behavioral repertoire and activities were recorded with video cameras. All castes and larval instars were determined and behavioral interactions were monitored and described, including feeding behaviors, grooming, nest maintenance, and inactivity. When two termites interacted, it was also determined which one was the donor or the recipient of the act. An ethogram was constructed by calculating relative frequency of each behavior for first instar larvae, second instar larvae, first instar workers, second instar workers or older, queen, king, soldiers and presoldiers. Larval instars, primary reproductives and soldiers were mostly passive during interactions. Workers performed most of the tasks; however, there was a difference of task divisions among worker instars. Young workers (W
1) performed most of the grooming of individuals in the central nest, while older workers (W
2+) provided nest maintenance and sanitation, by collecting fecal matter from most nest mates. In addition, older workers were mostly in charge of caring for the primary reproductives and the maintenance of the royal chamber. This study identified instar-specific activities and provides a first insight into caste and age polyethism in C. formosanus.
Full-text available · Article · Feb 2016 · Insectes Sociaux
[Show abstract][Hide abstract]ABSTRACT: This laboratory study reports the ability of Formosan subterranean termite, Coptotermes formosanus Shiraki, colonies to survive for at least 9 yr while restricted to a sweater box. Colonies survived by limiting queen size and worker numbers, allowing these bonsai colonies to thrive. Queen physogastry appeared to plateau with 9-yr-old queens not larger than 6-yr-old queens, but nearly triple the size of 2-yr-old queens. Nine-year-old colony worker numbers were not greater than 6-yr-old colonies, but worker numbers were greater than in 2-yr-old colonies. Such colony survival under conditions of restricted resources provides a mechanism for re-infestation of areas following extensive area-wide control efforts. "Bonsai" colonies are relevant to the ability of marginalized colonies to avoid detection and then expand and invade into areas once the large, mature colonies are eliminated, and their potential to produce alates to start new C. formosanus colonies in areas which have been subjected to colony elimination programs impacts termite management strategies.
Full-text available · Article · Dec 2015 · Journal of Economic Entomology
[Show abstract][Hide abstract]ABSTRACT: The purpose of this study was to evaluate survival and wood consumption of the Formosan subterranean termite, Coptotermes formosanus Shiraki, on ten different species of wood used as commercial lumber. Six of the wood species had natural resistance to termites and caused an average of >75% mortality. Southern yellow pine and spruce were the most palatable and teak was the most resistant of the wood tested. A test was also conducted to compare survival of termites on resistant wood with survival under starvation conditions after three and six weeks. After six weeks, survival of termites on teak was significantly lower than in the starvation control, suggesting that at least some of the termite mortality on teak may have been due to toxicity. Toxic chemical components of teak hold the most promise as wood preservatives.
Full-text available · Article · Jul 2015 · International Biodeterioration & Biodegradation
[Show abstract][Hide abstract]ABSTRACT: The common bed bug, Cimex lectularius (L.) (Hemiptera: Cimicidae) is undergoing a rapid resurgence in the United States during the last decade which has created a notable pest management challenge largely because the pest has developed resistance against DDT, organophosphates, carbamates, and pyrethroids, the latter class of insecticide being most commonly used today. Eight nonconventional insecticides Orange Guard (a.i., d-limonene), Natria Home Pest Control (a.i., soy bean oil and eugenol), RestAsure (a.i., sodium laurel sulfate, sodium chloride, and potassium sorbate), CedarCide (a.i. cedar oil), Essentria Broadcast Insecticide (a.i., 2-phenethyl propionate, rosemary oil, and peppermint oil), EcoSmart Organic Home Pest Control (a.i., 2-phenethyl propionate, clove oil, rosemary oil, peppermint oil, and thyme oil), Cirkil (a.i.,neem oil) and CimeXa (a.i., silica gel) were compared with two pyrethorids Bonide Bedbug Killer (a.i.,permethrin) and D-Force (a.i.,deltamethrin) as positive controls, and water for direct contact spray knockdown and lethal effects in the laboratory over 4 days. Orange Guard, CedarCide, Essentria, EcoSmart, and Cirkil provided extensive knockdown within 15 min (recovery was, at most, negligible), and caused 80 to 100% mortality within a day making them as effective as the two pyrethroids. CimeXa did not cause appreciable knockdown, but nearly complete mortality was achieved within a day. Product effects in terms of active ingredients and factors that might increase and decrease product effectiveness, such as cimicid aggregation behavior and residual effects, are discussed.
[Show abstract][Hide abstract]ABSTRACT: The giant reed, Arundo donax L. (Poaceae), is an invasive weed pest in the United States and other parts of the world, particularly in riparian habitats where it can hinder the flow of water and choke out indigenous vegetation. Conventional approaches to controlling A. donax have not been particularly effective, including burning, mowing, synthetic herbicides, bulldozing, and introduction of exotic biological control agents. One of the most commonly used botanically-based herbicidal compounds is d-limonene from citrus oil, but such natural, or organic, herbicides have not been assessed for their effects on A. donax. We tested two commercial citrus-based organic herbicides, BurnOut II (also contains eugenol) and Worry Free Weed and Grass Killer using topical applications at the recommended rates on mature (woody) plants, culms (lateral shoots on mature stalks that can propagate vegetatively), immature (< 1 year-old) stalks, and in soil and water for effects on culm shoot and root production. Although application to mature stalks and culms growing from the stalks resulted in rapid tissue injury, the plants recovered by producing more culms at internodes and a new dominant apical meristem. Different concentrations mixed into soil and water growing substrates where culms were planted caused stunting and delays in shoot and root production. Topical application to immature stalks were effective at killing the treated stalk, but the rhizome from which multiple stalks can grow was likely not affected by the local contact action of the organic herbicides.
[Show abstract][Hide abstract]ABSTRACT: Site fidelity by molting termites in Coptotermes formosanus colonies is a new addition to our understanding of lower termites’ behavior and biology. In our studies, workers in the colonies traveled from foraging sites to the central nest and molted in the proximity of eggs and reproductives. Although molting is an important issue when attempting to eliminate a subterranean termite colony using molt disrupters like chitin synthesis inhibitors (CSIs), our knowledge on spatial distribution of molting individuals that die under the effect of CSI in a colony is limited. Here we report the spread of death and response of the surviving individuals including reproductives to dead individuals in a colony. The aversion to the dead and decaying individuals causes physogastric queen to leave the original inhabited site in a colony and refuge at newer site every few days. Because mortality was an event observed only in the individuals undergoing molting under the effect of CSI, death was observed only around reproductives in the form of molting individuals with molting site fidelity. In the final few days of senescence of CSI baited colony, some reproductives were spotted in the bait chamber; which agreed with field observations.
[Show abstract][Hide abstract]ABSTRACT: A termite colony is composed of workers of different ages, but an age polyethism has yet to be reported in lower termites. We hypothesized the presence of age polyethism in workers of juvenile colonies of Coptotermes formosanus Shiraki (4yrs-old) and that individuals display a different behavior as a function of the distance from the central part of the nest, represented by the egg cluster. Two larval instars and two worker instars were determined by the head width of individuals of juvenile colonies placed in planar arenas. Grooming behavior and wood consumption of first and second instar workers were monitored at different distances from the egg cluster with a video camera. We observed that grooming behavior was mostly performed by the first instar workers close to the egg cluster, while second instar workers consumed wood throughout the nest most of the time. In addition, we observed that second instar workers performed larvae transportation near the egg cluster and groomed arena walls near the royal pair, while significantly smaller number of first instar workers were involved in these two tasks. Our results showed that age polyethism is present in C. formosanus workers and that the distance from the egg clusters affected the task performed by first and second instar workers.
[Show abstract][Hide abstract]ABSTRACT: This field study investigated the colony effect of a fipronil spot treatment applied to active infestations of Formosan subterranean termite, Coptotermes formosanus Shiraki. Spot treatments were applied to a single active independent monitor from each of four colonies in which multiple independent monitors were established. All treated monitors were abandoned, and the contents of the treated monitors were replaced with untreated wood at the approximately 30-d posttreatment inspection. All colonies survived treatment and only one colony exhibited long-term effects, which included significant reductions in termite collections and increased worker size. The affected colony was treated within 1 m of its primary nest. Two colonies exhibited a correlation between monitor termite production and distance from treatment. Distance appears to be a factor limiting fipronil's colony effects. The Formosan subterranean termite may not be a good candidate for the exterior perimeter and localized interior treatment label option because of the large range and size of the colony.
Full-text available · Article · Apr 2014 · Journal of Economic Entomology
[Show abstract][Hide abstract]ABSTRACT: Three-year old incipient colonies of Coptotermes formosanus Shiraki were placed in planar arenas, and their behavioral repertoire and activities at different distance from the colony center, i.e. egg pile, was recorded by using a video camera. Two instar each of larva and worker caste were identified by measuring the head width of individuals. Larvae were fed and groomed by workers. First instar workers did most of the grooming in the colony, but second instar workers tunneled through sand to feed on wood. There was trophallaxis between workers of the same instar and between the first and second instar. Larvae were primarily fed by the first instar workers through stomodeal feeding, suggesting an age polyethism among workers of the young colonies of C. formosanus.
[Show abstract][Hide abstract]ABSTRACT: Podophyllotoxin is currently in high demand as the lead chemical precursor for the anti-cancer drugs etoposide and teniposide. We conducted a two-phase study: (i) screening of Juniperus and other related species and identified Juniperus virginiana as the species with the highest podophyllotoxin concentration and (ii) established the limits of variations of podophyllotoxin and essential oil content and composition in J. virginiana in the United States. In the second phase of the study. J. virginiana trees at 49 locations in Mississippi. Alabama, Tennessee, and North Dakota were sampled and analyzed for both podophyllotoxin and essential oil. Both the essential oil and podophyllotoxin had similar concentration ranges as percent of dry J. virginiana leaves. Hence the following qualitative grouping with respect to concentration of natural products in the leaves was assigned: very high (>0.3%), high (0.2-0.3%), medium (0.1-0.2%), and low (<0.1%). Based on the above qualitative grouping, the J. virginiana accession were divided into 10 different groups (chemotypes). The J. virginiana accessions also differed in essential oil composition, with wide variation of individual constituents. Based on the essential oil composition, the J. virginiana accessions were divided into the following groups (chemotypes): (1) safrole-limonene-linalool; (2) safrole-beta-pinene-limonene-linalool; (3) beta-pinene-limonene; (4) limonene; (5) limonene-linalool; (6) limonene-safrole; (7) limonene-safrole-beta-pinene; (8) beta-pinene-limonene-bornyl acetate; (9) beta-pinene-limonene-linalool-bornyl acetate; and (10) myrcene-limonene chemotype. The essential oil of two of the J. virginiana chemotypes showed differential antioxidant activity. J. virginiana leaves, a by-product from the timber industry could be used as a sustainable source for both podophyllotoxin and essential oil. The availability of various chemotypes offers an opportunity for the development of cultivars for commercial production of podophyllotoxin and essential oil with specific compositional profile to meet the market requirements.
Full-text available · Article · May 2013 · Industrial Crops and Products
[Show abstract][Hide abstract]ABSTRACT: The AED 2000 and 2010 are extremely sensitive listening devices which can effectively detect and monitor termite activity through a wave guide (e. g. bolt) both qualitatively and quantitatively. Experiments conducted with one to ten thousand termites from differing colonies infesting wood in buckets demonstrated that acoustical emission detector readings significantly increased when number of termites increased. Termites were also detected in infested trees with the installation of several wave guides into their trunks. These devices can detect termites and changes in termite activity caused by changes in termite numbers, making it an effective pest management professional and research tool for finding and evaluating termite infestations and efficacy of treatments in specific locations.
Full-text available · Article · Apr 2013 · Sociobiology
[Show abstract][Hide abstract]ABSTRACT: Nine years of periodic acoustical monitoring of 93 trees active with Formosan subterranean termite, Coptotermes formosanus Shiraki, were evaluated for imidacloprid tree foam and noviflumuron bait to reduce termite activity in trees. Long term, imidacloprid suppressed but did not eliminate termite activity in treated trees. Noviflumuron bait did not significantly reduce the proportion of trees with high termite activity but significantly increased the number of trees with no termite activity. Noviflumuron changed termite distribution by possibly eliminating only some fraction of numerous colonies whereby surviving colonies avoided trees containing dead termites.
Full-text available · Article · Apr 2013 · Sociobiology
[Show abstract][Hide abstract]ABSTRACT: Two new polyacetylene thiophenes, echinopsacetylenes A and B (1 and 2), were isolated from the roots of Echinops transiliensis. The structures of 1 and 2 were elucidated on the basis of spectroscopic analyses and chemical transformations. Echinopsacetylenes A (1) is the first natural product possessing an α-terthienyl moiety covalently linked with another thiophene moiety. Echinopsacetylenes B (2) is the first natural thiophene conjugated with a fatty acid moiety. Echinopsacetylene A (1) showed toxicity against the Formosoan subterranean termite (Coptotermes formosanus).
[Show abstract][Hide abstract]ABSTRACT: Among the termite infestations in the United States, the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), is considered to be the most devastating termite pest. This pest most likely invaded North America as a result of the disembarkation of wooden military cargo at the port of New Orleans that arrived from Asia during and after World War II. It has now spread over other states, including Texas, Florida, South Carolina and California. Devastation caused by C. formosanus in North America has been estimated to cost $ US 1 billion a year. Over the past decades, organochlorines and organophosphates, the two prominent classes of termite control agents, have been banned owing to environmental and human health concerns. At the present time, phenylpyrazoles, pyrethroids, chloronicotinyls and pyrroles are being used as termite control agents. Mammalian toxicity and seeping of these compounds into groundwater are some of the drawbacks associated with these treatments. The instruction for the application of these termiticides indicate ground water advisory. Hence, with the increasing spread of termite infestation there is an increased need to discover effective, environmentally friendly and safe termite control agents with minimal mammalian toxicity.
Chromene analogs derived from a natural-product-based chromene amide isolated from Amyris texana were tested in a collaborative discovery program for effective, environmentally friendly termite control agents. Several chromene derivatives were synthesized and characterized as a novel class of potential termiticides, followed by bioassays. These compounds exhibited significantly higher mortalities compared with untreated controls in laboratory bioassays.
Chromene derivatives have been shown to be a potential novel class of termiticides against Formosan subterranean termites.
[Show abstract][Hide abstract]ABSTRACT: The effect of barriers of dry soil on the ability of Formosan subterranean termites, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), to construct tunnels and find food was evaluated. Termite movement and wood consumption in a three-chambered apparatus were compared between treatments with dry soil in the center container and treatments where the soil in the center container was moist. When a wood block was located in the release container, termites fed significantly more on that block, regardless of treatment or soil type. In the treatment with dry clay, none of the termites tunneled through the dry clay barrier to reach the distal container. When termites had to tunnel through a barrier of dry sand, topsoil, or clay to reach the sole wood block, there was no effect on wood consumption for the sand treatment, but there was significantly less feeding on wood in the treatments with dry topsoil or clay. When foraging arenas had a section of dry sand in the center, the dry sand significantly reduced tunneling in the distal section after 3 days, but not after 10 days. There was a highly significant effect on the ability of termites to colonize food located in dry sand. Only one feeding station located in dry sand was colonized by termites, compared with 11 feeding stations located in moist sand.
Full-text available · Article · Nov 2011 · Journal of Insect Science
[Show abstract][Hide abstract]ABSTRACT: Periodic sampling of 43 independent monitors, initially active with Formosan subterranean termite, Coptotermes formosanus Shiraki, or the eastern subterranean termite, Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae), was conducted to evaluate the effects of cellulose baits containing one of three chitin synthesis inhibitors (CSIs)-diflubenzuron, hexaflumuron, or chlorfluazuron-on termite populations. Diflubenzuron at 0.1% active ingredient (AI, wt:wt) had no noticeable effect on termite populations. Chlorfluazuron (0.25% [AI]) significantly reduced termite populations in approximately 3 yr. Chlorfluazuron used after > 2-yr diflubenzuron treatment significantly reduced termite populations within months. This suggests diflubenzuron exposure increased the termite's sensitivity to chlorfluazuron accelerating population collapse. Hexaflumuron (0.5% [AI]) also reduced termite populations in approximately 2 yr. The process of removing most detectable termite populations from the approximately 160,000-m2 campus of the Southern Regional Research Center, New Orleans, LA, with CSIs baits required approximately 3 yr. Adjustments in the specific bait formulations and application procedures might reduce time to suppression. Establishment of new independent termite populations provides a mechanism to minimize the effects of baits. Remedial control measures around and under structures should be considered when implementing an area wide management strategy.
Full-text available · Article · Jun 2011 · Journal of Economic Entomology
[Show abstract][Hide abstract]ABSTRACT: The objective of this study was to determine how seasonal changes affect the foraging activity and wood consumption of the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), in New Orleans, LA. There was a significant correlation between wood consumption and air temperature, soil temperature, and soil moisture, but not precipitation or number of rainy days. In the first year of the study, wood consumption was the lowest in December, February, and March. Wood consumption in January was not significantly different from consumption during the rest of the year. There were no seasonal changes in the number of underground monitoring stations occupied by termites. In the second year of the study, wood consumption was lowest from January to March. There was a significant decrease in the number of monitoring stations occupied by termites during the winter. This study determined that C. formosanus will remain in monitoring stations and resume feeding during warmer periods of a mild winter if average soil temperatures remain above 15 degrees C. Only prolonged periods of cold weather, with average soil temperatures below 15 degrees C, caused a significant number of termites to abandon underground monitoring stations. Seasonal changes in foraging activity would probably only disrupt baiting programs during severe winters in New Orleans, LA.
Full-text available · Article · Jun 2011 · Journal of Economic Entomology