Sulfadimethoxine and rhodamine B as oral biomarkers for European badgers (Meles meles)

A field study was carried out on Little Island (County Waterford, Ireland) in June 2000 to evaluate the potential of a bait-marking system for use in European badgers (Meles meles). Two oral biomarkers, sulfadimethoxine (SDM) and rhodamine B, were incorporated into fishmeal baits and distributed by hand at main sets in five test territories for 3 consecutive days. In parallel, non-biomarked baits were distributed at a single control territory. The objectives of the study were to: (1) assess the effects of SDM and rhodamine B on palatability and thus bait acceptance, and (2) investigate the marking capacity of SDM and rhodamine B in serum and hair samples taken from badgers. Trapping was carried out in each territory for 5 consecutive days immediately after bait distribution. Analysis of data revealed that 90-100% of baits were removed in four of the test territories and from the control territory. In the fifth test territory, 61% of baits were removed. Of the badgers (n = 26) trapped in the test territories, 18 (69%) were positive when tested for both biomarkers. In contrast, the remaining eight animals and those captured in the control territory (n = 6 badgers) were negative. In the marked animals, the highest levels of SDM were recorded in serum samples taken soon after bait distribution. Thereafter, the levels declined in each badger over the course of the study. In contrast, rhodamine B was readily detectable by fluorescence microscopy of hair samples throughout the period of study. The results indicate that SDM and rhodamine B act as systemic markers in badgers and have potential future applications for monitoring of oral vaccine uptake.     

Evaluating seasonal bait delivery to badgers using rhodamine B

In the UK and Ireland, research on the control of bovine tuberculosis in badgers includes the development of a palatable bait for oral delivery of a vaccine and a means of its deployment in the field. In the present study, we carried out field deployment of bait according to the established method of bait marking in early spring and early summer to compare the effects of seasonality on bait uptake rates. All baits contained rhodamine B (RhB) which was subsequently detected in the hair and whiskers of captured badgers. During the 8 days of bait feeding at 14 badger setts, 99% of baits deployed in spring, and 100% of those deployed in summer were removed. The presence of RhB in captured badgers indicated high rates of uptake amongst adult badgers in spring (93%) and summer (98%). Only cubs captured in summer showed evidence of having taken bait (91%). Between 67% and 100% of each social group was estimated to have taken bait. The detection of RhB in 96% of badgers captured at outlier setts, where bait was not fed, suggested that deployment at main setts alone may be sufficient to target a relatively high proportion of the badger population. The number of baits deployed per marked badger suggested that a similar level of uptake might be achievable using fewer baits. The results clearly demonstrate the potential value of the bait-marking methodology for delivering vaccine baits to badgers during spring and summer, but that deployment in early summer is necessary to target cubs.     

Iophenoxic Acid as a Long-Term Marker for Wild Boar

ABSTRACT Chemical markers are increasingly used to investigate consumption of baits used to deliver vaccines, toxicants, and contraceptives. We evaluated whether ethyl-iophenoxic acid (Et-IPA) and propyl-iophenoxic acid (Pr-IPA) can be used as long-lasting systemic bait markers for wild boar (Sus scrofa). We presented captive wild boar with baits treated with either Et-IPA or Pr-IPA at 5 mg/kg (low dose), 10 mg/kg (medium dose), and 20 mg/kg (high dose) of body weight. We collected serum from each boar at 5 time points: 5 days, 3 weeks, 6 weeks, 11 weeks, and 39 weeks following ingestion of iophenoxic acid-treated baits. We detected both Et-IPA and Pr-IPA for ≥39 weeks after ingestion. Throughout the trial, the Et-IPA we found in serum was proportional to the amount eaten. At each time point, animals in the high-dose group had significantly more Et-IPA than animals in the low-dose group. We concluded that both compounds can be used as long-lasting markers in wild boar and that Et-IPA can also be employed as quantitative marker to indicate multiple bait uptake. Both compounds have potential applications in the context of vaccination, fertility, and population control campaigns, where baits are used to deliver pharmaceuticals, and in behavioral studies to establish spatial and temporal patterns of bait uptake.     

Comparative study of integrated pest management and baiting for German cockroach management in public housing

This study assessed the cost and effectiveness of a building-wide cockroach integrated pest management (IPM) program compared with bait alone treatment in public housing. In total, 12 buildings (66 apartments) were treated and monitored for cockroach infestations over 7 mo. The buildings were divided into two groups: bait treatment and IPM. Apartments in the bait alone group were treated with Maxforce FC Select (0.01% fipronil) during the first 12 wk and Maxforce Roach Killer Bait Gel (2.15% hydramethylnon) from 16 wk when necessary. For the IPM group, cockroaches were flushed and vacuumed at the beginning of the study; sticky traps were placed in all apartments to monitor and reduce cockroach numbers; educational materials were delivered to the residents; and Maxforce FC Select and Maxforce Roach Killer Bait Gel were applied to kill cockroaches. Two seminars were presented to the manger, and Community Service Program staff of the Gary Housing Authority to help gain tenant cooperation in the program. Effects of the treatments were monitored using sticky traps (six per apartment) at 2, 4, 8, 12, 16, and 29 wk after treatment. More treatments were applied during each monitoring visit when necessary. Those apartments with high levels of infestations (> or =12 cockroaches in six traps) before treatment were used to compare the IPM and bait only treatments. IPM resulted in significantly greater trap catch reduction than the bait treatment. The IPM (n=12) and bait only treatment (n=11) resulted in 100.0 and 94.6%, respectively, reduction in trap catch after 16 wk. At 29 wk, only one apartment in the IPM group had a high level (>12 cockroaches) of cockroach infestation. In contrast, five apartments in the bait treatment group had high level infestations at 29 wk based on overnight trapping counts; thus, IPM is a more sustainable method of population reduction. Sanitation levels in the IPM group significantly improved at 29 wk (n=11) compared with that at the beginning of the study. The sanitation levels in the bait treatment group remained similar throughout the experiment (n=9). The cumulative cost of IPM was significantly higher than that of the bait treatment. The median costs per apartment during 29 wk were 64.8 dollars and 35.0 dollars for the IPM and bait treatment, respectively. The median amount of bait used per apartment in the IPM and bait treatment was 45.0 and 50.0 g, respectively. The cost of the IPM group for the 29 wk service was similar to that of the bait treatment group. We expect that IPM will provide better control at similar cost compared with bait treatment beyond 29 wk.     

Evaluation of attractant flavours for use in oral vaccine baits for badgers (<Emphasis Type="Italic">Meles meles</Emphasis>)

European badgers (Meles meles) are a wildlife reservoir for Mycobacterium bovis infection (tuberculosis) in Ireland and the UK and are implicated in the transmission of infection to livestock. Vaccination of badgers with the human BCG vaccine (Bacille Calmette Guerin) is considered as an important strategy to reduce the burden of disease in this species, and a pragmatic approach is likely to involve oral vaccination. In this study, we evaluated nine different flavours for use as attractants in a prototype oral vaccine bait for European badgers (M. meles): aniseed, apple, cocoa powder, carob powder, curry, fish, garlic, peanut and strawberry. The bait matrix was composed of a natural lipid formulation, developed as a vehicle for oral vaccination against tuberculosis in wildlife. A ‘food for work’ paradigm was employed during the trials to ensure the animals were actively seeking the baits. The trials showed carob and cocoa powders were equally attractive and more attractive than any of the other candidates. Carob and cocoa show potential as bait attractants for badgers and might form part of a novel vaccine delivery system.     

A Behaviorally-Explicit Approach for Delivering Vaccine Baits to Mesopredators to Control Epizootics in Fragmented Landscapes

Despite the widespread use of aerial baiting to manage epizootics among free-ranging populations, particularly in rabies management, bait acceptance and seroconversion rates often are lower than required to eliminate spread of disease. Our objectives in this study, therefore, were to evaluate the performance of stratified bait distribution models derived from resource selection functions (RSF) on uptake of placebo rabies baits by raccoons (Procyon lotor) and Virginia opossums (Didelphis virginiana), as well as the probability of bait uptake as a function of proximity to bait distribution areas in fragmented agricultural ecosystems. Among 478 raccoons and 108 opossums evaluated for presence of Rhodamine B (RB) across 8 sites, only 26% of raccoons and 20% of opossums exhibited marking consistent with bait consumption 14–24 days post-baiting. The effective area treated, based on 90% kernel density estimators of marked individuals, ranged from 99–240 ha larger than bait distribution zones, with RB marked individuals captured up to 753m beyond the bait zone. Despite incorporation of RSF data into bait distribution models, no differences in uptake rates were observed between treatment and control sites. These data likely reflect the underlying constraints imposed by the loss and fragmentation of habitat on animal movement in heterogeneous landscapes, forcing individuals to optimize movements at coarse (i.e., patch-level) rather than fine spatial scales in highly fragmented environments. Our data also confirm that the probability of bait acceptance decreases with increasing distance from bait zone interiors, even within the zone itself. Thus, although bait acceptance was confirmed beyond bait zone boundaries, the proportion of vaccinated individuals may comprise a small minority of the population at increasing distances from baiting interiors. These data suggest focal baiting creates a buffered area of treated individuals around bait zones or bait stations, but repeated treatments may be needed to achieve sufficient uptake to eradicate disease.     

Effectiveness of attract-and-kill systems using methyl eugenol incorporated with neonicotinoid insecticides against the oriental fruit fly (Diptera: Tephritidae)

Laboratory bioassays and field trials were conducted to evaluate an "attract-and-kill" system using methyl eugenol (ME) with neonicotinoid insecticides against male oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae). In laboratory bioassays, mortality of male flies resulting from the conventional toxicant, naled was 98.3-100% at 24 through 72 h after treatment, whereas the neonicotinoid insecticides imidacloprid and acetamiprid caused only approximately 60-80% at 24 through 72 h after treatment. In the assays of residual effect, naled was persistent up to 96 wk, whereas imidacloprid or acetamiprid was persistent up to 150 wk, resulting in 38.9 or 61.2% male mortality, respectively. Imidacloprid, in particular, caused a delayed lethal effect on flies. In another experiment, male mortality within 28 wk from clothianidin, another neonicotinoid insecticide, was approximately 80% after exposure for 24 h, suggesting a delayed lethal effect similar to those treated with imidacloprid, and mortality was up to 91.8%, if observed, 72 h after treatment. In field trials, attractiveness was similar between ME alone and ME incorporated with naled or neonicotinoids, indicating that addition of these insecticides to ME in traps is not repellent to B. dorsalis males. Using an improved wick-typed trap with longer attractiveness for simulating field application, addition of imidacloprid or acetamiprid maintained 40.1 or 64.3% male mortality, respectively, when assayed once every 2 wk from traps placed in orchards for 42 wk without changing the poison, whereas incorporation with naled resulted in as high as 98.1% after 34 wk and approximately 80% at 42 wk, indicating that persistence is increased compared with sugarcane fiberboard blocks for carrying poison attractants. This study also suggests that neonicotinoid insecticides could be used as an alternative for broad-spectrum insecticides as toxicants in fly traps.     

Evaluation of iophenoxic acid and rhodamine B for marking feral ferrets (Mustela furo)

Abstract

The blood marker iophenoxic acid, and the fluorescent dye rhodamine B, were evaluated as means of assessing bait consumption in the ferret, Mustela furo. Iophenoxic acid was elevated above baseline concentrations for a minimum of 28 days after dosing, indicating that it is a suitable medium‐term marker. Rhodamine B marked ferrets for a maximum of 7 days, and would therefore have limited operational use with feral ferrets. Iophenoxic acid was used in a field trial to assess the effectiveness of a newly developed baiting strategy for control of wild ferrets. All 21 ferrets captured after field baiting with iophenoxic acid had elevated levels of serum iodine, indicating that the newly developed baiting strategy is highly effective for marking ferrets.     

Field tests of environmentally friendly malathion replacements to suppress wild Mediterranean fruit fly (Diptera: Tephritidae) populations

This article reports a large-scale field test of two environmentally friendly malathion replacements on wild populations of the Mediterranean fruit fly, Ceratatis capitata (Wiedemann): spinosad, a bacteria-derived toxin, and phloxine B, a red dye with phototoxic properties. The comparison test was conducted on 11 coffee fields infested with wild populations of Mediterranean fruit fly on the Hawaiian island of Kauai with 8-wk protein bait sprays with and without toxicants. To assess effectiveness, adults were trapped and larval infestation levels were evaluated with fruit collections. Malathion was found to be the most effective treatment. However, the two replacements gave significant levels of control, and because they are environmentally safer, should be considered for eradicating incipient populations of this invasive species of fruit fly. Cage tests were also conducted to ensure that the wild flies consumed the bait and to assess how long the bait-toxicant combination remained effective in the field. Although spinosad and phloxine B were found to be effective up to 1 wk, malathion remained effective at least 2 wk.     

Use of Rhodamine B to Reveal Patterns of Interspecific Competition and Bait Acceptance in Raccoons

Abstract: Passive treatment of raccoons (Procyon lotor) through distribution of vaccine-laden baits recently has emerged as a potential solution to address health and economic conflicts associated with raccoon rabies and may have applications in the management of other pathogens carried by raccoons if frequent bait deployments are used. Consumption of baits by nontarget species reduces the efficiency in which baits can be used to manage wildlife disease, although no study has explicitly evaluated the influence of bait competitor density on the ability to treat raccoons. Our objectives were to use the biomarker Rhodamine B (RB) to 1) evaluate patterns of raccoon bait acceptance as a function of competition with Virginia opossums (Didelphis virginiana), the dominant bait competitor; 2) characterize attributes of opossum bait acceptance to improve efficiency of raccoon treatment; and 3) evaluate the effect of repeated bait exposure on rates of bait acceptance as may be required in the management of wildlife disease issues beyond rabies. Identifying bait consumption by individuals based on the presence of an RB mark in a sample of whiskers, we used logistic regression to model raccoon and opossum bait acceptance as a function of bait availability, previous exposure to baits, demographic attributes, and an index of time spent in the baited area (residency index). For both raccoons and opossums, the best measure of bait availability was the variable number of baits per opossum. The most parsimonious logistic regression model for raccoon bait acceptance included the variables baits per opossum, exposure history, and residency index. The strength of the variable baits per opossum relative to competing measures of bait availability indicated bait consumption by opossums significantly limited the ability to treat raccoons. The most parsimonious model for opossum acceptance was composed of the variables baits per opossum, sex, weight, residency index, baits per opossum X sex, and weight X sex. Patterns of opossum bait acceptance likely were driven by effects of bait availability and sex-dependent differences in movement. Our results call attention to the importance of bait competition in limiting the ability to effectively treat raccoon populations through distribution of baits and suggest managers incorporate information on density of bait competitors, particularly opossums, in allocation of baits.     

Efficacy of wax matrix bait stations for Mediterranean fruit flies (Diptera: Tephritidae)

Tests were conducted that evaluated efficacy of wax matrix bait stations for Ceratitis capitata (Wiedemann) adults in Guatemala. Bait stations were exposed to outdoor conditions to determine effect of weathering on longevity as indicated by bait station age. Results of laboratory tests found that bait stations with spinosad and ammonium acetate remained effective for at least 31 d compared with pesticide-free controls, although there was some loss of efficacy over time. Percentage mortality for bait station strips with 2% spinosad and 1% ammonium acetate decreased from 100 +/- 0.0% on day 0 to 70 +/- 7.1% after 31 d. Ammonia concentration had little effect on percentage mortality although there was some indication that ammonia concentration affected number of flies observed on the bait stations. Bait station strips (one per cage) were more effective than controls for 6-8 wk when tests were conducted in field cages (3 m diameter x 2 m), but only 2-3 wk when tests were conducted in large (2.5 m high and 6.0 m wide and 7.5 m long) field cages. Longevity was restored when multiple bait stations (3, 6, or 12) were deployed per cage. Bait stations containing methomyl were used for field tests of efficacy for wild flies. Dipped lure bait stations, which were made by coating two edges of commercial ammonium acetate and trimethylamine lures, killed six times more flies than corn cob bait stations dipped into a Nulure/malathion solution. They also killed more flies than pesticide-free controls for 8 wk.     

Acceptance of simulated oral rabies vaccine baits by urban raccoons

In summer 1986, a study was conducted to evaluate raccoon (Procyon lotor) acceptance of oral baits that could be used for rabies vaccination. One thousand wax-coated sponge bait cubes were filled with 5 mg of a seromarker (iophenoxic acid), placed in polyethylene bags, and hand-distributed in an 80 ha area within an urban National Park in Washington, D. C. (USA). After 3 wk, target and nontarget animals were trapped and blood samples collected to evaluate bait uptake. Thirty-three of 52 (63%) raccoons had elevated blood iodine levels indicating they had eaten at least one bait, 13 (25%) were negative, and six (12%) had marginal values. These results indicate that sponge baits hand-placed at a density of 12.4/ha can reach a significant proportion of an urban raccoon population. Implications for oral rabies vaccination of raccoons are discussed.     

Rhodamine B as a systemic hair marker for assessment of bait acceptance by stoats (Mustela erminea)

Abstract

Rhodamine B (RB) is a dye that becomes incorporated into the structure of growing hair of animals that ingest it, appearing as an orange‐red fluorescent band detectable under a fluorescent‐light microscope. This marker was evaluated as a means of assessing bait acceptance by stoats (Mustela erminea L.). Eleven wild‐caught captive stoats were each fed a broken hen egg injected with 25 mg of RB on two occasions, 5 weeks apart. This was equivalent to 62–108 mg kg^–1, depending upon stoat weight, on each occasion. At least three facial whiskers were collected from each dosed stoat on each of two sampling dates (giving a total of at least six whiskers from each stoat). The sampling dates varied from 1 to 17 weeks after first dosing. Whiskers were also collected from one of the dosed stoats that died of other causes 19 weeks after first dosing, and from four stoats not dosed with RB. All 11 of the stoats fed RB had at least one fluorescent band in at least one of the sampled whiskers. None of the four stoats not fed RB had fluorescent bands in their whiskers. The marking persisted in all dosed stoats for at least 6 weeks, and in one dosed stoat for at least 19 weeks after dosing. However, only 56% of the 91 whiskers inspected from the dosed stoats had fluorescent bands, and only 9% of the whiskers had two fluorescent bands, representing the two doses of RB. The distance between the two fluorescent bands indicated a mean whisker growth of 0.6 mm day^‐1. The distance from the base of the whiskers to the base of the fluorescent bands was broadly related to the time after ingestion of bait containing RB. However, the variation was too great for distance along the whisker to be reliably used as a quantitative measure of time after bait ingestion. The technique can be used to assess bait acceptance in the field provided all stoats are sampled within c. 4–6 weeks of baiting, and at least 6–9 whiskers are sampled from each stoat.     

Use of rhodamine B as a biomarker for oral plague vaccination of prairie dogs

Oral vaccination against Yersinia pestis could provide a feasible approach for controlling plague in prairie dogs (Cynomys spp.) for conservation and public health purposes. Biomarkers are useful in wildlife vaccination programs to demonstrate exposure to vaccine baits. Rhodamine B (RB) was tested as a potential biomarker for oral plague vaccination because it allows nonlethal sampling of animals through hair, blood, and feces. We found that RB is an appropriate marker for bait uptake studies of <60 days in black-tailed prairie dogs (C. ludovicianus) when used at concentrations <0.5% of bait mass dosed to deliver >10 mg RB per kg target animal mass. Whiskers with follicles provided the best sample for RB detection.     

Quantifying the relative predation pressure on bumblebee nests by the European badger (Meles meles) using artificial nests

Bumblebee populations are declining. Factors that impact the size and success of colonies act by either limiting resource availability (bottom‐up regulation) or causing mortality, for example, pesticides, disease, and possibly predation (top‐down regulation). The impact of predation has not been quantified, and so, the current study used novel artificial nests as a proxy for wild bumblebee nests to quantify the relative predation pressure from badgers in two habitats: woodland and grassland, and at two nesting depths: surface and underground. Badgers occur across most parts of the UK and are known to predate on bumblebee nests. We found that significantly more artificial nests (pots containing bumblebee nest material) were dug up compared with control pots (pots without bumblebee nest material). This shows that artificial nests have the potential to be used as a method to study the predation of bumblebee nests by badgers. In a location of high badger density, predation pressure was greater in woodland than grassland, whereas no difference was observed in relation to nest depth. Woodland and grassland are shared habitats between bumblebees and badgers, and we suggest that higher predation may relate to activity and foraging behavior of badgers in woodland compared with grassland. We discuss how badger predation in different habitats could impact different bumblebee species according to their nesting behaviors. Understanding the relative impact of badger predation on bumblebee colonies provides key information on how such top‐down regulation affects bumblebee populations.     

荧光探针在光动力疗法亚细胞损伤位点研究中的应用

目的：应用荧光探针在光动力疗法研究中检测亚细胞损伤位点。方法：传代培养鼠肺毛细血管内皮细胞,将血卟啉单甲醚(HMME)与内皮细胞共同孵育24小时后,加入线粒体探针Bhodamine-123、内质网探针DioC6(3)和溶酶体探针Lucifer yellow分别对细胞器染色。首先采用激光共聚焦显微镜对光敏剂进行亚细胞定位。应用荧光显微镜汞灯照射激发光敏剂的光动力效应,加入ROS探针H2DCF-DA检测产生的单线态氧。分别在激发前后采集Pdloclamine-123、Lucifer yellow和DioC6(3)的荧光图像。结果：线粒体探针Phodamine-123的荧光图像在光动力损伤前后差异显著,原有形态特点发生明显改变;Phodamine-123在光动力损伤后再分布于细胞核区。结论：血卟啉单甲醚介导的光动力效应导致亚细胞水平多位点损伤,线粒体和核膜可能是PDT敏感位点;荧光探针标记检测光动力损伤亚细胞位点方法简便可靠。     

Hair type,intake, and detection method influence Rhodamine B detectability

Rhodamine B (RB) is a popular bait-marking tool in wildlife research, although its use has required many assumptions about marking reliability. These assumptions have limited dosage ranges and detection methods in research applications. Identification of alternate detection methods, hair types, and dosage rates could create new opportunities for RB use and potentially reduce adverse effects on target animals. We examined the relationship between hair types, dosage rate, and detection method for RB applications using black rats (Rattus rattus) in laboratory settings. We gave study animals varying doses of RB, and examined vibrissae and guard hairs for the detection of RB bands using ambient light, ultraviolet (UV) light, and fluorescence microscopy techniques. Fluorescence microscopy detected more RB marked hairs than UV light or ambient light. Fluorescence microscopy was more sensitive to RB dose rate detection; with receiver operating characteristic curves suggesting that the minimum dose rates at which RB intake can be correctly detected are 3.9 and 33 mg/kg for vibrissae and guard hairs, respectively. Guard hair RB detection was less reliable under ambient light and UV lamps, but equally detectable as vibrissae under fluorescence microscopy. Our results confirmed the interrelationship between dosage and detection methods in the efficacy of bait markers. We demonstrated that guard hairs can be a reliable hair type for the detection of RB. This application is less invasive than sampling animal tissues to detect bait uptake. © 2012 The Wildlife Society.     

Spatio-temporal ecology and density of badgers <Emphasis Type="Italic">Meles meles</Emphasis> in the Swiss Jura Mountains

This study reports for the first time data on the spatio-temporal ecology of badgers living in a cold and wet mountain region (Swiss Jura Mountains). The home range, movements, activity patterns and habitat use of three badgers (two males, one female) were examined using radiotelemetry. Average home range size was 320 ha (MCP 100%), but the ranging behaviour of badgers varied at a seasonal scale. As in other regions, badgers were strictly nocturnal or crepuscular and showed a marked reduction of activity in the winter period. From spring to autumn, animals were active for an average (±SD) of 8.1 ± 2.4 h and travelled up to 9,460 m each night (mean±SD, 5,160 ± 2,600 m). The nightly distance travelled by badgers was positively correlated with their travel speed, the duration of the activity period and the used area, but not with night length. Year-round, the radio-collared animals avoided pastures and the vicinity of houses during their night trips. In winter and spring, individual badgers used forests and wooded pastures more than expected according to their availability, whereas cereal fields were actively selected in summer and autumn. Den-watching, night-lighting and radio-tracking data suggest that badgers live in pairs in this wet and cold region. Population density estimates range from 0.4 to 1.5 individuals/100 ha. We discuss the importance of trophic resources and climate as factors influencing badger behavioural ecology.     

Field evaluation of the bait toxicant chlorfluazuron in eliminating Coptotermes acinaciformis (Froggatt) (Isoptera: Rhinotermitidae)

Two aspects of the Exterra Termite Interception and Baiting System (Ensystex, Fayetteville, NC) were evaluated in a field experiment using 13 termite mounds near Townsville, Australia. First, a cellulose-acetate powder containing either 0.05% wt:wt or 0.25% wt:wt chlorfluazuron (Requiem, Ensystex, Fayetteville, NC) was tested for its efficacy in eliminating colonies of the xylophagous mound-building subterranean termite Coptotermes acinaciformis (Froggatt). The moist bait matrix was replenished during the first inspection of 10 mounds (five mounds by two treatments) used in the experiment. Second, a single application of the moist bait matrix was used on three additional mounds to test termite responses and the effectiveness of 0.25% wt:wt chlorfluazuron. Although there was no evidence of repellence, there was little removal of replenished bait. Five colonies were eliminated by 0.05% wt:wt chlorfluazuron and five colonies by 0.25% wt:wt chlorfluazuron: another colony was moribund, and elimination appeared imminent. Colony decline was first suspected some 12 wk after bait application, and colony elimination was confirmed, by destructive sampling, about 5 wk later. Colony elimination may have occurred within 12 wk. One colony was an anomaly and did not succumb to the effects of the toxicant. Another colony was not eliminated because of invasion of the baiting system by ants. Ants, principally Iridomyrmex purpureus (F. Smith) group and Papyrius nitidus (Mayr) group, occurred commonly in the stations during the experiment. Microcerotermes sp. was found in five of the C. acinaciformis mounds, after colony elimination. Inspections of small sections of mounds and wooden dowels inserted into mounds were reliable methods for monitoring colony health.     

Rhodamine-B-marked eggs identify individual predators of artificial nests

Investigations of nest predation are often limited by the researchers’ inability to identify nest predators accurately. I tested a chemical bait marker, Rhodamine B (RB), as an indicator of egg predation at artificial ground nests. In a pen trial, the presence of characteristic fluorescent bands in one or more facial vibrissae from all treatment animals confirmed the suitability of RB as a bait marker in the introduced European hedgehog (Erinaceus europaeus). In a field trial in which artificial ground nests were baited with RB-dosed eggs, five of 21 trapped hedgehogs showed evidence of RB ingestion. One animal showed markings indicating two temporally separate predation events. This ability to identify nest predators to species, demographic class, or individual level could lead to more focused control programmes. Other potential uses of this technique include investigation of individual foraging behaviour, calibration of predation rates in artificial nest studies, estimation of the efficacy of poisoned eggs as a control method, and testing for bait or poison uptake by non-target species.