Response of Reticulitermes spp. (Isoptera: Rhinotermitidae) in northern California to baiting with hexaflumuron with sentricon termite colony elimination system

Colonies of Reticulitermes spp. were baited with prototype and commercial Sentricon stations (Dow AgroSciences LLC, Indianapolis, IN) to test the efficacy of hexaflumuron in different concentrations and bait matrices and to document reinvasion of the foraging territories vacated by eliminated colonies. Seven colonies of Reticuliternes spp. from two sites were characterized with cuticular hydrocarbon analyses and mark-release-recapture and agonistic behavioral studies. Three colonies were observed as controls and four colonies were baited. When a connection between the bait station and the monitoring station could not be confirmed by mark-release-recapture studies, the results of the baiting were equivocal. The monitoring stations of a colony at our wildland site were devoid of termites 406 d after baiting with one Sentricon station, but became reoccupied with the same species of termites approximately 6 mo after baiting. A colony at the residential site was baited with 0.5% hexaflumuron in the Recurit II bait matrix; 60 d later termites were absent from all monitoring stations. These monitoring stations remained unoccupied for > or = 18 mo. Foraging Reticulitermes spp. appeared in three of the seven monitoring stations 18, 24, and 36 mo after baiting, respectively. Using cuticular hydrocarbon analyses and agonistic behavior studies, we determined that the Reticulitermes spp. occupying these monitoring stations were from three different colonies; none were members of the original colony destroyed by baiting. Another colony at the residential site was baited using a noncommercial, experimental bait; 52 d later termites were absent from all monitoring stations. The monitoring stations remained unoccupied for > or = 9 mo. A different Reticulitermes sp. colony invaded one monitoring station 9 mo after baiting.     

Dimensionally stable sensors for a continuous monitoring program to detect subterranean termite (Isoptera: Rhinotermitidae) activity

A dimensionally stable sensor composed of a closed-cell polyethylene sheet on which a silver particle circuit was painted and sandwiched between two spruce stakes was tested for use in a monitoring program to detect subterranean termites. Sensors were connected to a datalogger for continuous monitoring of sensor circuit breakages over 12 mo, and were manually inspected monthly to assess sensor performance. The mean monthly sensor accuracy for three field test sites was 98.7%, with most false responses caused by early timing of the monthly inspection when termites entered the station before damaging the sensor circuits. Mean sensor longevity (the time for a sensor circuit to break in the absence of termites) of the dimensionally stable sensors was 11.7 mo; a substantial improvement over the 4.4-mo longevity recorded previously for wooden sensors.     

Porites ulcerative white spot disease: description, prevalence, and host range of a new coral disease affecting Indo-Pacific reefs

The results of an investigation of a new coral disease affecting Indo-Pacific reefs are presented. Porites ulcerative white spot disease (PUWS) is characterized by discrete, bleached, round foci, 3 to 5 mm in diameter, that may either regress or progress to full tissue-thickness ulcerations that coalesce, occasionally resulting in colony mortality. Monitoring of 25 diseased and 5 healthy reference colonies for 17 mo revealed that advanced stages of the disease were characterized by lesion coalescence, partial colony death (i.e. portions of the colony still alive; n = 17) and total colony death (n = 2). Field transmission experiments revealed that 95% of healthy colonies developed lesions within 5 wk after continual exposure to diseased branches, while 60% of the reference colonies remained healthy. The host range of PUWS includes branching and massive Porites spp., and prevalence per species was positively correlated with species density. On 10 reefs surveyed in the Central Philippines, 22 +/- 7% (mean +/- SE) of poritid colonies were infected, and the disease was present on 80% of the surveyed reefs. Poritids are dominant Indo-Pacific reef builders; a disease targeting this genus could cause major shifts in community structure over time. This report contributes to the limited knowledge of PUWS impacts in this region.     

Development of the stages of the cycle in mouse seminiferous epithelium after transplantation of green fluorescent protein-labeled spermatogonial stem cells

To study the mechanism of male germ cell differentiation, testicular germ cells carrying green fluorescent protein (GFP) as a transgene marker were transplanted into infertile mouse testis. Fluorescence-positive seminiferous tubule segments colonized with GFP-labeled donor germ cells were isolated and measured, and differentiated germ cells were analyzed in living squashed preparations. Cell associations in normal stages of the seminiferous epithelial cycle were also studied and used as a reference. Two months after transplantation, the average length of the colonies was 1.3 mm. The cell associations of transplanted colonies were consistent with those of normal stages of the cycle. However, stages of the cycle were not necessarily identical in different colonies. Three months after transplantation, the average length of transplanted colonies was 3.4 mm, and the cell association in every portion of a colony was similar to that of the corresponding stage of the cycle. Even in long fused colonies made by transplantation of a higher concentration of male germ cells, the cell association patterns in various regions of a single colony were similar and consistent with those of some of the normal stages of the cycle. Development of different stages inside the colony was observed by 6 mo after transplantation. These results indicate that the commencement of spermatogonial stem cell differentiation occurs randomly to develop different stages of the cycle in different colonies. Then, each colony shows one single stage of the cycle for a long time, even if it becomes a very large colony or fuses with other colonies. These observations indicate the existence of some kind of synchronization mechanism. By 6 mo, however, normal development of the stages of the cycle appeared in seminiferous tubules.     

A computerized system for remote monitoring of subterranean termites near structures.

Sensors comprising wooden stakes painted with conductive circuits of silver particle emulsion were inserted in Sentricon stations in soil near structures. Sensors were wired to a datalogger that was programmed to test for circuit breakage every 2 h and store the data in its memory. A host computer was programmed to access the datalogger through telephone communication lines for data download every 4 d. The computerized monitoring system was tested in three remote sites, and site visits were conducted monthly for 6 mo to examine system accuracy in detecting termite activity. The mean monthly accuracy for the system to correctly report the presence (true positive) or absence of termites (true negative) in the stations was 85%, but the accuracy at 6 mo after system installation ranged from 41 to 79%. Mean sensor longevity, defined as the time for a sensor circuit to break in the absence of termites, was approximately 4.4 mo.     

Comparison of the behavioural and physiological responses to humidity of five species of dry-wood termites, Cryptotermes species

ABSTRACT. A circular humidity gradient apparatus with a porous cellulose substrate was used to compare the humidity responses of pseudoworkers (immature wood-feeding forms) of five species of dry-wood termites. Four of these species are widely distributed pests of buildings: Cryptotermes brevis (Walker), C. cynocephalus Light, C. dudleyi Banks and C. havilandi (Sjöstedt). The fifth species, C. naudei Coaton, has not been recorded from buildings. C. havilandi, C. cynocephalus and C. naudei were found to tend to group and feed at humidites above 90% r.h., while C. dudleyi pseudoworkers avoided humidities above 90% r.h. and below 70% r.h. These results accord with the results of studies on the effects of relative humidity on feeding and reproduction of these species. The behaviour of the most widespread species, C. brevis , seems to be closely associated with its ability to undergo acclimatization and to feed efficiently at either medium ( c. 60%) or high ( c. 90%) relative humidity. C. brevis kept at 89% r.h. showed an increased tendency to group at humidities above 90%, with a lower temperature preference, changes in faecal pellet formation and, for one population at least, an increased tolerance of exposure to saturated air. The humidity preferences at constant temperature were compared with the temperature preferences of the same individuals examined in uniform humidity. The value of behavioural responses as indicators of physiological differences between species and populations is considered.     

Elimination of subterranean termite (Isoptera: Rhinotermitidae) colonies using a refined cellulose bait matrix containing noviflumuron when monitored and replenished quarterly

Using a quarterly (3-mo) monitoring and bait-replenishment interval, 122 subterranean termite colonies throughout the United States were baited with a refined cellulose bait matrix containing 0.5% noviflumuron. All colonies were eliminated in less than 1 yr after initiation of baiting as determined by long-term monitoring and genetic markers. Sixty-three percent of the colonies were eliminated during the first quarter after the initiation of baiting and 77% of colonies were eliminated after consuming two bait tubes or less. This suggests that a single baiting cycle and bait installed in response to a single active monitoring device were sufficient to eliminate the majority of colonies. Although termites temporarily abandoned stations after depleting bait, workers resumed feeding when baits were replenished. Colonies that consumed large amounts of bait before elimination foraged into multiple stations, thus allowing adequate amounts of bait to sustain feeding. The time to eliminate termite colonies with bait replenished quarterly was similar to that previously reported for laminated cellulose bait replenished monthly. Our data support the conclusion that extending the bait replenishment interval from monthly to quarterly for bait tubes with refined cellulose containing 0.5% noviflumuron did not adversely impact colony elimination.     

Elimination of field colonies of a mound-building termite Globitermes sulphureus (Isoptera: Termitidae) by bistrifluron bait

The efficacy of Xterm, which contains 1% bistrifluron, in the form of cellulose bait pellets was evaluated for its efficacy in eradicating field colonies of the mound-building termite Globitermes sulphureus (Haviland) (Isoptera: Termitidae). The termite mounds were dissected at the end of the experiment to determine whether the colonies were eliminated. By approximately 2 mo postbaiting, the body of termite workers appeared marble white, and mites were present on the body. The soldier-worker ratio increased drastically in the colonies, and the wall surface of the mounds started to erode. Colony elimination required at least a 4-mo baiting period. Mound dissection revealed wet carton materials (food store) that were greatly consumed and overgrown by fast-growing fungi. Decaying cadavers were scattered all over the nests. On average, 84.1 +/- 16.4 g of bait matrix (68.9 +/- 13.4%, an equivalent of 841 +/- 164 mg of bistrifluron) was consumed in each colony. Moreover, we found that a mere 143 mg of bistrifluron was sufficient to eliminate a colony of C. sulphureus.     

Biofilm thickness variability investigated with a laser triangulation sensor

Measurement of the surface roughness and thickness of biological films is laborious and usually destructive, thus hampering research in this area. We developed a laser triangulation sensor (LTS) set-up for the fast and nondestructive measurement of these biofilm parameters during growth. Using LTS measurements, the morphological development of a dichloromethane-(DCM) degrading biofilm cultured on a wetted-wall column was studied. The measurements show that the biofilm develops faster at the entrance of the reactor. The biofilm consisted of a base film in which microbial colonies were embedded. The biofilm-surface area gradually increased by 23% compared to the bare surface due to the formation of a large number of these colonies. The number and shape of these colonies were followed in time. Using LTS measurements, biofilms distinctly different in surface roughness could be distinguished in a laboratory trickling filter removing DCM from a waste gas. The consequences of the observed surface characteristics for the reaction-diffusion process in the biofilm and for the falling film hydrodynamics are discussed.     

Modeling the interactions of Lactobacillus curvatus colonies in solid medium: consequences for food quality and safety

The growth process of Lactobacillus curvatus colonies was quantified by a coupled growth and diffusion equation incorporating a volumetric rate of lactic acid production. Analytical solutions were compared to numerical ones, and both were able to predict the onset of interaction well. The derived analytical solution modeled the lactic acid concentration profile as a function of the diffusion coefficient, colony radius, and volumetric production rate. Interaction was assumed to occur when the volume-averaged specific growth rate of the cells in a colony was 90% of the initial maximum rate. Growth of L. curvatus in solid medium is dependent on the number of cells in a colony. In colonies with populations of fewer than 10(5) cells, mass transfer limitation is not significant for the growth process. When the initial inoculation density is relatively high, colonies are not able to grow to these sizes and growth approaches that of broth cultures (negligible mass transfer limitation). In foods, which resemble the model solid system and in which the initial inoculation density is high, it will be appropriate to use predictive models of broth cultures to estimate growth. For a very low initial inoculation density, large colonies can develop that will start to deviate from growth in broth cultures, but only after large outgrowth.     

Effect of fipronil on subterranean termite colonies (Isoptera: Rhinotermitidae) in the field

To assess possible colony-level effects of fipronil, a commonly used nonrepellent termiticide, we conducted a field study of eight houses in the Raleigh, NC, area with infestations of the eastern subterranean termite Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae). We installed an extensive grid of in-ground monitoring stations on each property (mean = 68.6 monitors per property) and collected samples from these stations as well as from mud tubes in the structure and wood debris in the yard for approximately 6 mo. We genotyped all samples by using microsatellite markers to identify the number and locations of colonies present on each property. Houses were treated with either a full treatment (n = 5) or exterior/localized interior treatment (n = 3). After treatment, the monitors were checked monthly for 3 mo and then quarterly for 3 yr to track the fate of colonies. Wood debris in natural areas was checked semiannually for 3 yr. All 11 of the treated colonies (those attacking structures) disappeared within 90 d of treatment and were not found again. These colonies were presumed to be eliminated. In contrast, 60% of untreated colonies (those located > 6 m from the foundation wall at the time of treatment) continued to persist throughout the study, as did 25% of the likely treated colonies (those occupying monitors 0.5 m from the foundation wall where the treatment was applied). Our results provide strong evidence for potent colony wide effects of fipronil on subterranean termites leading to colony suppression and likely colony elimination under field conditions.     

Population density, species abundance, and breeding structure of subterranean termite colonies in and around infested houses in central North Carolina

Pressure from subterranean termites is known to vary geographically across the United States, but there are few quantitative studies concerning the threat of structural infestation for any geographic region. We assessed the number and locations of termite colonies present on 20 infested residential properties in central North Carolina, where subterranean termite pressure is considered to be heavy. This was achieved by using microsatellite markers to determine colony identity of termites collected over 6-14 mo from mud tubes in structures, below-ground monitors, and wood debris in the yard. In total, we identified 188 distinct colonies and determined their breeding structures. Reticulitermes flavipes (Kollar) was by far the most common species, accounting for nearly 90% of all colonies; the remaining colonies belonged to Reticulitermes hageni Banks and Reticulitermes virginicus (Banks). In four cases, there were two colonies infesting a structure simultaneously; in all other cases only a single colony was detected in the structure. Colony densities were high, averaging 62 colonies per ha (25 per acre) with a maximum of 185 colonies per ha (75 colonies per acre). Foraging ranges of R. flavipes and R. hageni colonies were generally small (<30 linear m), and most colonies were headed by a single pair of monogamous reproductives with nearly all the remaining colonies headed by relatively few inbreeding descendants of the original monogamous pair. These results provide the most detailed picture to date of the number, distribution, and colony characteristics of subterranean termite colonies located in and around residential structures.     

Evaluation of hexaflumuron for controlling the subterranean termite Coptotermes curvignathus (Isoptera: Rhinotermitidae) in Malaysia

Cellulosic bait matrices containing 0.5% hexaflumuron were tested against field colonies of the subterranean termite Coptotermes curvignathus Holmgren in Malaysia. Foraging activities of the termites were first monitored for several months by using survey stakes and wood bundles placed in underground monitoring traps. Infested stakes were replaced with bait devices. Termite workers to act as recruits were collected from infested stakes and placed in the bait devices. Subsequent activities of the termites were monitored by examining and weighing the wood in the monitoring traps. Data show that the four colonies had populations of 166,288-709,052 foragers and mean wood consumption rates of 305.9-508.2 g/mo per trap. These colonies ceased their activities at all monitoring devices 25-44 d after baiting had commenced. Colonies consumed approximately 27-79 g of bait matrix or 137.5-395 mg of hexaflumuron. Thus, C. curvignathus colonies could be monitored, characterized, baited, and foraging eliminated by using a bait matrix containing hexaflumuron.     

Disruption of reproductive activity of Coptotermes formosanus (Isoptera: Rhinotermitidae) primary reproductives by three chitin synthesis inhibitors

Effects of the chitin synthesis inhibitors (CSIs) diflubenzuron, hexaflumuron, and lufenuron on the Formosan subterranean termite, Coptotermes formosanus Shiraki, primary reproductives were studied in the laboratory. Incipient colonies were established by collecting and pairing C. formosanus alates and placing them in dishes containing an artificial diet. Three groups of 56 colonies each were fed with a diet containing 10 ppm of one of each of the CSIs and were compared with a control group fed with an untreated diet. All eggs oviposited by treated young queens failed to hatch at the end of 6 mo. Estimated queen fecundity was significantly lower in the lufenuron treatment compared with the control group. Fecundity of hexaflumuron-treated queens did not differ significantly from that of queens from the control group and the other treatments. Adult mortality was significantly higher in the diflubenzuron and lufenuron treatments than in the control group at the end of 6 mo., but not in the hexaflumuron treatment. All the pairs died within 8 mo. in the diflubenzuron and lufenuron treatments, even after treatment was suspended at the end of 6 mo. Mortality in the hexaflumuron treatment was significantly higher than in the control group by the end of 9 mo. The three CSIs tested eliminated reproduction in C. formosanus by preventing egg hatching and induced adult mortality. Possible mechanisms by which CSIs induce termite adult death are discussed.     

Elimination and reinvasion studies with Coptotermes formosanus (Isoptera: Rhinotermitidae) in Louisiana

Three Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), colonies located inside the 12.75-ha Louis Armstrong Park, New Orleans, were selected for elimination by using the chitin synthesis inhibitor hexaflumuron. Once eliminated, each vacated foraging territory was monitored for reinvasion by neighboring C. formosanus colonies, Reticulitermnes flavipes (Kollar) (Isoptera: Rhinotermitidae) colonies, or both. Each selected colony was eliminated in approximately 3 mo by using baits containing hexaflumuron. Overall activity of each untreated colony in the park remained unchanged during the same period. New C. formosanus and R. flavipes activity was detected in two of the three vacated territories, and in both areas, within days of selected colony elimination. The third vacated territory was completely reoccupied by a new C. formosanus colony approximately 7 mo later. Mark-recapture studies and DNA fingerprinting confirmed the distinctness of the reinvaders from eliminated and neighboring colonies.     

Evaluation of the shaking technique for the economic management of American foulbrood disease of honey bees (Hymenoptera: Apidae)

Shaking is a nonantibiotic management technique for the bacterial disease American foulbrood (AFB) (Paenibacillus larvae sensu Genersch et al.), in which infected nesting comb is destroyed and the adult honey bees, Apis mellifera L. (Hymenoptera: Apidae), are transferred onto uncontaminated nesting material. We hypothesized that colonies shaken onto frames of uninfected drawn comb would have similar reductions in AFB symptoms and bacterial spore loads than those shaken onto frames of foundation, but they would attain higher levels of production. We observed that colonies shaken onto drawn comb, or a combination of foundation and drawn comb, exhibited light transitory AFB infections, whereas colonies shaken onto frames containing only foundation failed to exhibit clinical symptoms. Furthermore, concentrations of P. larvae spores in honey and adult worker bees sampled from colonies shaken onto all comb and foundation treatments declined over time and were undetectable in adult bee samples 3 mo after shaking. In contrast, colonies that were reestablished on the original infected comb remained heavily infected resulting in consistently high levels of spores, and eventually, their death. In a subsequent experiment, production of colonies shaken onto foundation was compared with that of colonies established from package (bulk) bees or that of overwintered colonies. Economic analysis proved shaking to be 24% more profitable than using package bees. These results suggest that shaking bees onto frames of foundation in the spring is a feasible option for managing AFB in commercial beekeeping operations where antibiotic use is undesirable or prohibited.     

Experimental Brucella abortus infection in wolves

Four juvenile male wolves (Canis lupus) each received an oral dose of 1.6-1.7 x 10(12) colony-forming units of Brucella abortus biovar 1 isolated from a bison (Bison bison) in Wood Buffalo National Park (Canada), and two others served as negative controls. Infected wolves did not show clinical signs of disease but did develop high Brucella antibody titers. Small numbers of B. abortus were excreted sporadically in feces until day 50 postinoculation (PI). Very small numbers of the bacterium were isolated from urine of only one wolf late on the same day that it was infected, and very small numbers of colonies of B. abortus were obtained from buccal swabs of three wolves for up to 48 hr PI. Two infected wolves euthanized 6 mo after the start of the experiment had no lesions, and colonies of B. abortus were isolated from thymus and most major lymph nodes. The other two infected wolves euthanized 12 mo after the start of the experiment had no lesions, and smaller numbers of brucellae were recovered from fewer lymph nodes compared with the wolves killed 6 mo earlier. The sporadic excretion of very small numbers of brucellae by the wolves was insignificant when compared with the infective dose for cattle. Brucella abortus, brucellosis, Canis lupus, pathogenesis, serology, wolf.     

Importance of lipids for queen fecundity and colony growth of Coptotermes formosanus (Isoptera: Rhinotermitidae)

The importance of lipids for queen fecundity and colony growth of Coptotermes formosanus Shiraki was studied. Groups of 100 incipient colonies of C. formosanus were reared on artificial diet containing nine different soy lecithin concentrations. Eggs were counted every 15 d for a 5-mo period at 27 +/- 1 degrees C, 93 +/- 5% RH, and 0:24 h (L:D) photoperiod. Fecundity per queen was estimated using a developmental rate-based graphic integration technique. At the end of a 1-yr period, the progeny of each colony was counted and recorded. Analysis of variance showed significant differences in queen fecundity and hatched progeny in colonies raised on various diets. Single linear regression analysis showed a small but significant linear increase in queen fecundity and hatched progeny per colony with increasing lecithin concentration. Increase in lecithin concentration explained approximately 2, 4, and 8% of the increase in queen fecundity of colonies surviving 6 mo and 1 yr and number of workers and soldiers in 1 yr-old colonies, respectively. This indicates that, although intake of lipids increases queen fecundity and colony growth of C. formosanus, other factors not measured in this study alone or in combination with lecithin play major roles.     

Population recovery and spatial dynamics of colony recruitment in a harvester ant: a case study in a park

The recovery process of Messor aciculatus (Fr. Smith) harvester ant colonies from habitat disturbance by construction work in an urban park was investigated from 1989 to 1994. Colonies located in 1989 were considered to be survivors of the disturbance, and colonies located for the first time after 1990 were considered to be recruits. The colonies continuously increased in number after the disturbance, and the population size more than doubled just after the disturbance. Analyses of the nest site distribution of colonies in 1989 and 1994 suggest that landform modification destroyed some of them, and that the changed nest site distribution in 1989 affected the distribution in 1994, or, in other words, the disturbance indirectly affected the nest distribution 5 years later. Analyses of the nearest neighbor to each colony suggested that established colonies would obstruct newly recruited colonies around their nests. Construction may open up space for recruitment colonization by removing established colonies, and may also create suitable conditions by destruction of original vegetation, or returning vegetation to the early stages of plant community succession. As a result, the disturbance may facilitate the subsequent recruitment of new colonies and rejuvenate the population.     

Male germ line stem cells have an altered potential to proliferate and differentiate during postnatal development in mice

Spermatogonial stem cells (SSCs) continuously support spermatogenesis after puberty. However, accumulating evidence suggests that SSCs differ functionally during postnatal development. For example, mutant mice exist in which SSCs support spermatogenesis in the first wave after birth but cease to do so thereafter, resulting in infertility in adults. Studies using a retroviral vector have shown that the vector transduces pup SSCs more efficiently than adult SSCs, which suggests that pup SSCs divide more frequently. Thus, it is hypothesized that the SSCs in pup and adult testes have different characteristics. As an approach to testing this hypothesis in the present study, we investigated the proliferation kinetics of pup SSCs (6-9 days old) and their self-renewal/differentiation patterns for the first 2 mo after transplantation, and compared them to those of adult SSCs. Using serial transplantation, we found that the number of pup SSCs declined over the first week after transplantation. Thereafter, it increased ~4-fold by 1 mo and ~9-fold by 2 mo after transplantation, which indicates that pup SSCs continuously proliferate from 1 wk to 2 mo after transplantation. Compared to the proliferation of SSCs derived from adult intact testes, that of pup SSCs was lower at 1 mo but similar at 2 mo, indicating the delayed proliferation of pup SSCs. However, the pup SSCs regenerated spermatogenic colonies at 1 mo that were similar in length to those of SSCs from adult intact testes. Therefore, these results suggest that some functional differences exist in SSCs during postnatal development, and that these differences may affect the abilities of SSCs to self-renew and differentiate.