Bait Pellets Research Articles

Toxicity of a management bait for grass carp (Ctenopharyngodon idella) incorporated with Antimycin A.

No current technology can specifically target grass carp (Ctenopharyngodon idella) for control within aquatic ecosystems. Rotenone and Carbon Dioxide-Carp are currently the only available registered pesticides for grass carp; they are nonselective and typically applied throughout the water, equally exposing target and native species. A more selective control tool or pesticide application could be used by resource managers to support mitigation efforts. Development of delivery systems that exploit carp feeding strategies could increase selectivity of pesticides and minimize effects on native fishes. A pesticide with selective delivery could be less labor intensive and used within an integrative pest management strategy. The present study examined Antimycin A toxicity in juvenile and sub-adult grass carp and rainbow trout (Oncorhynchus mykiss) across two routes of exposure. Water-based toxicity studies were used to calculate the concentration to cause lethality in 50% of treated fish (LC50) at 24-h, while oral gavage toxicity studies were used to calculate the dose to cause lethality in 50% of treated grass carp and rainbow trout (LD50) 24- to 96-h. Although rainbow trout were more sensitive than grass carp to Antimycin A through water-based exposure, oral toxicity was similar between species, even with inherent gastrointestinal morphological differences. Successful delivery of a lethal dose of Antimycin A to grass carp was achieved through an oral route of exposure using the rapeseed bait and shows promise for registration as a control tool and eventual use in pest management plans. Although a lethal dose of Antimycin A could be incorporated into a single bait pellet, more bait was required to achieve desired mortality when fed to fish under laboratory conditions.

Control of Musca domestica (House Fly) in Poultry Units using Delta Traps

Background: House fly menace is a major problem in poultry farms and nearby households. Though application of insecticides is one of the major approaches in house fly control, development of insecticide resistance is widely prevalent. Use of house fly traps is an ecofriendly alternate strategy in control of house flies. In the present study, delta traps were used to control house flies in poultry units. Methods: Red acrylic delta traps with two different pellet baits (FMP and FMPB) were placed at ground level in poultry units housing caged layer chicken with a distance of 90 cm between two traps for seven days continuously and trial was replicated six times. Trapped flies were counted, sexed and species identified. Spot cards were used to determine house fly density pre-and post-trapping. Correlation of house fly population with meteorological parameters was assessed. Result: Out of the 80410 flies trapped, 52.74 per cent (42415 flies) and 47.25 per cent (37994 flies) were trapped in FMPB and FMP pellet baited traps, respectively. Daily fly trapping pattern showed variations. Overall trap catches were dominated by female flies. Reduction in spot card count was 36.34 per cent after deployment of traps. Trap catches correlated positively with temperature, relative humidity and wind velocity. Two species Musca domestica domestica and Musca domestica vicina were identified.

FLEA CONTROL ON PRAIRIE DOGS (CYNOMYS SPP.) WITH FIPRONIL BAIT PELLETS: POTENTIAL PLAGUE MITIGATION TOOL FOR RAPID FIELD APPLICATION AND WILDLIFE CONSERVATION.

Sylvatic plague is a widespread, primarily flea-vectored disease in western North America. Because plague is highly lethal to endangered black-footed ferrets (Mustela nigripes, BFFs) and the prairie dogs (Cynomys spp., PDs) on which BFFs depend for habitat and prey, minimizing the impacts of plague is a priority at BFF reintroduction sites. We developed a new, flour-based bait pellet containing 0.84 mg of fipronil and weighing ∼1.25 g (FipBits). We measured the degree and duration of flea control on black-tailed PDs (C. ludovicianus) in Montana and on Gunnison's PDs (C. gunnisoni) in Arizona, USA from 2018-2020. FipBits were distributed on treated plots one time at a rate of 125/ha. Fleas were virtually eliminated in Montana from 1 mo posttreatment to 1 yr later and remained substantially depressed 2 yr posttreatment. With the split colony design, we probably underestimated the degree of flea control achieved with FipBits due to crossover edge effects along the arbitrary line dividing the plots. Flea control in Arizona was significant from 1 mo posttreatment to 1 yr later, but flea abundance had recovered by 2 yr posttreatment. Flea control was evaluated from 2020-2021 in South Dakota, USA on four plots treated with three concentrations of fipronil in FipBits (0.68, 0.71, and 0.83 mg/FipBit). Fleas were essentially eliminated for 10 mo on the 0.83-mg plot and were substantially reduced on the two 0.71-mg plots. Fleas were reduced on the 0.68-mg plot, but the degree of control was less than observed on other treated plots. Impacts of plague on PDs and BFFs would probably be greatly reduced by the levels of flea control observed with FipBits. Options for expanded FipBit evaluations are being pursued for what may become a highly practical, affordable, and effective plague mitigation tool.

Numerical Simulation and Analysis of Feeding Uniformity of Viscous Miscellaneous Fish Bait Based on EDEM Software

The feeding characteristics of viscous miscellaneous fish bait were studied in order to place the bait into existing equipment. Through the feeding experiment and discrete element numerical simulation of miscellaneous fish pellet feed, the feeding characteristics of the sticky miscellaneous fish pellet feed in the silo were analyzed. The main factors affecting the uniform feeding of miscellaneous fish pellet bait were obtained, including the size of the feeding mouth of the silo, the size of the inclination angle of the silo, and the effect of external forces. According to the simulation and experiment results, the optimum design of the discharging device was carried out, including the optimization of the structure of the bin, the design of the agitation device and the optimization of the rotating parameters of the agitation device. The research and development of the stirred discharging device was completed, realizing the uniform, continuous and complete discharging of the mixed fish particle bait. Its feasibility was verified through the simulation and prototype experiment.

The effects of brodifacoum cereal bait pellets on early life stages of the rice coral Montipora capitata.

Midway Atoll in the Northwestern Hawaiian Islands is home to ground nesting birds that are threatened by invasive mice. Planned rodent eradication efforts for the island involve aerial application of cereal bait pellets containing the chemical rodenticide brodifacoum. Given the nature of the application method, drift of cereal bait pellets into the coastal waters surrounding Midway Atoll is unavoidable. To understand whether cereal bait pellets impact marine invertebrates, gametes and larvae of the reef-building coral Montipora capitata were exposed to brodifacoum, cereal bait pellets containing brodifacoum, and inert cereal bait pellets without the rodenticide. Fertilization success and larval survival were assessed at nominal brodifacoum concentrations of 1, 10, and 100 ppb. Fertilization success decreased by 15% after exposure to 100 ppb brodifacoum solutions. Larval survival was not reduced by exposure to brodifacoum solutions. Cereal bait pellets containing brodifacoum reduced fertilization success at 10 ppb brodifacoum in 0.4 g per L pellet solutions by 34.84%, and inhibited fertilization at 100 ppb brodifacoum in 4 g of pellet per L solution. Inert cereal bait pellets had similar effects, reducing fertilization success at 0.4 g of pellet per L by 40.50%, and inhibiting fertilization at 4 g per L pellet solutions. Larval survival was reduced by >43% after prolonged exposure to 4 g per L pellet solutions. The highest concentration used in this study was meant to represent an extreme and unlikely condition resulting from an accidental spill. Our findings indicate large amounts of cereal bait pellets entering the coastal environment of Midway Atoll, if occurring during a coral spawning event, would reduce coral reproduction by decreasing fertilization success. It is difficult to know the ecologically relevant concentrations of cereal bait pellets in coastal environments due to unavoidable bait drift after land applications, but results indicate small amounts of pellet drifting into coastal environments would not severely reduce coral reproductive capacity. Best management practices should consider known coral reproductive periods when scheduling applications of pellets on tropical islands to reduce the risk of negative impacts of large-scale accidents on corals.

Relative palatability and efficacy of brodifacoum-25D conservation rodenticide pellets for mouse eradication on Midway Atoll

Invasive mice (Mus spp.) can negatively impact island species and ecosystems. Because fewer island rodent eradications have been attempted for mice compared to rats (Rattus spp.), less is known about efficacy and palatability of rodenticide baits for mouse eradications. We performed a series of bait acceptance and efficacy cage trials using a standard formulation of brodifacoum-based rodenticide on wild-caught mice from Sand Island, Midway Atoll, to help inform a proposed eradication there. Mice were offered ad libitum brodifacoum pellets along with various alternative food sources, and a “no choice” treatment group received only bait pellets. Mortality in the no choice trial was 100%; however, when offered alternative foods, mice preferred the alternative diets to the bait, leading to low mortality (40%). Because there was concern that the bittering agent Bitrex® in the formulation may have reduced palatability, we conducted a subsequent trial comparing brodifacoum bait with and without Bitrex. Mortality in the with-Bitrex treatment group was slightly higher, indicating that the bittering agent was not likely responsible for low efficacy. Laboratory trials cannot account for the numerous environmental and behavioral factors that influence bait acceptance nor replicate the true availability of alternative food sources in the environment, so low efficacy results from these trials should be interpreted cautiously and not necessarily as a measure of the likelihood of success or failure of a proposed eradication.

Delta Traps with Pheromone Pellet Baits to Lure House Flies in Poultry Houses

The field efficacy of pheromone-food bait pellets to lure house flies was evaluated using delta traps in poultry houses. Different pellet baits with fish meal alone (FM), fish meal+(Z)-9-tricosene (FMP), and fish meal+(Z)-9-tricosene+butylated hydroxyl toluene (FMPB) were prepared and evaluated in a poultry house using delta traps to lure house flies. Out of the 30611 flies trapped, a maximum of 30.62% (9374 flies) were attracted to delta traps baited with FMPB pellets followed by 29.97% (9175 flies) with FMP pellets, 19.11% (5850 flies) with FM pellets, and 20.29% (6212 flies) in control without bait. Average number of flies trapped/trap/day (FTD) with FM, FMP, FMPB pellets and control were 119.38, 187.24, 191.30 and 126.77, respectively and averages of flies trapped/trap/week (FTW) respectively were 835.71, 1310.71, 1339.14 and 887.42. Fly attraction towards different pellet baits was statistically significant (ꭓ2 value = 1847.81** p<0.01HS). Overall trap catches were dominated by female flies irrespective of baits (17469 females, 57.00% vs. 13142 males, 42.93%). Male: female sex ratio with FM, FMP, FMPB and control was 5:7, 4:5, 4:5 and 5:8, respectively (ꭓ2 value = 1330.39** p<0.01HS for male flies and 668.75** (p<0.01)HS for female flies). Results revealed that pheromone-food lure- based pellet baits were effective house fly attractants in delta traps.

A lesson for planning rodent eradications: interference of invasive slugs during the Gough Island mouse eradication attempt in 2021

Context House mice (Mus musculus) are the main drivers of biodiversity declines on Gough Island (6500 ha; 40°21′S, 009°53′W), central South Atlantic. A mouse eradication operation was planned, the largest global attempt targeting only this species. Understanding and managing challenges of operating at such scales are crucial for maximising the chance of eradication success. The Gough Island mouse eradication attempt was implemented between June and August 2021, after years of planning and trials. We expected poor weather and negligible non-target bait consumption. Aims We aimed to assess the impact of expected and unexpected challenges faced during the eradication operation on Gough Island, namely poor weather and rapid bait disappearance. Methods We set up bait degradation plots across the primary habitats to monitor the impact of expected heavy rain on bait pellets. In contrast, bait availability monitoring and slug laboratory trials were set up ad hoc in response to unexpected observations of high bait consumption by invasive slugs in the lowlands, where both slugs and mice are more abundant. Key results Bait degradation rates were very different between the highlands and the lowlands, with bait in the highlands lasting about six times longer, despite bait pellets receiving more precipitation and the highlands being persistently under cloud. Bait availability in the lowlands dropped by &gt;80% within a few days of the second and third bait application, down to critically low levels (~2 kg ha−1). Importantly, mouse activity was negligible by this time. Non-native slugs appeared to be the main cause of such a sudden drop in rodent bait availability. Conclusions The expected rainy weather was not a significant direct cause of bait degradation in the short term. In contrast, the unexpected slug interference, overlooked in earlier planning trials, resulted in major adjustments of the baiting strategy. Indeed, the rapid bait disappearance in the lowlands triggered the third bait application over this area, at a higher rate. This was not enough, as mice are still present. Implications This is the first report of slug interference during aerial rodent eradications. Our results illustrate how interference by non-target species could affect future pest eradications using baits and should, as far as possible, be assessed early during planning.

Allogrooming, Self-grooming, and Touching Behavior as a Mechanism to Disperse Insecticides Inside Colonies of a Leaf-Cutting Ant.

Toxic baits, containing the active ingredients sulfluramid or fipronil, are the main methods to control leaf-cutting ants of the genera Atta Fabricius, 1805, and Acromyrmex Mayr, 1865 (Hymenoptera: Formicidae). However, the insecticide dispersion among members of the colony during the control needs further studies. We studied whether the behaviors of allogrooming, self-grooming, and contact among individuals spread the insecticides among those of the colony. The insecticides sulfluramid and fipronil (0.1% and 1.0% (w/w)) were applied topically in groups of workers of Atta sexdens (Linnaeus, 1758), and the social interactions among them with or without insecticide were studied. In addition, toxic baits (sulfluramid or fipronil) were provided to colonies and their behavioral acts were observed. At the end of the experiment, colony mortality, number and mass of dead workers, and mass of wet waste were compared between ant nests receiving baits and ants with topical application. In the topical application, behavioral analysis showed higher interaction between ants in the colonies and touch and allogrooming behaviors as the most frequent in those that received the concentrations of sulfluramid. In the baits, the behavior of licking the pellet and allogrooming was more frequent. Colony mortality was faster for those that received topical application, especially with the insecticide fipronil (0.1%). However, the number and mass of dead workers was similar between topical application and toxic baits. In the toxic baits, the licking behavior of the bait pellets and subsequent allogrooming probably dispersed the insecticides. In the topical application, the route of the insecticide occurred by excessive touches among workers, with subsequent allogrooming. Thus, allogrooming, self-grooming, and touching among workers increased the dispersion of insecticides among members of the ant colonies.

The Efficacy of Pine Wood Pellets reinforced with Active Hexaflumuron Against the Subterranian Termite Coptotermes curvignathus Holmgren

Bait formulation using hexaflumuron is the most used baiting techniques because it is relatively friendly to the environment. One of the potential wood species for bait formulation for termites is pine wood. The resin in pine wood can reduce termites preference. Therefore, the resin contained in pine wood needs to be reduced so that the level of termites preference for pine wood can be increased. This study aims to determine the efficacy of the bait formulation in the form of pellets from pine wood (Pinus merkusii Jungh er de Vries) which was pre-treated with presto (0.4 bar, 100 °C) for one, two, three, four, and five hours with active hexaflumuron (0.25%) against subterranean termites Coptotermes curvignathus. Pine wood chips were treated with presto for one hour, two hours, three hours, four hours, and five hours. The treated pine wood chips then made into sawdust by 40-60 mesh. Pine sawdust then added with hexaflumuron (0.25%) and formed into pellets without adding any adhesive material and then fed to the subterranean termites C. curvignathus (JIS K 1571: 2010). Solid pine wood used as a control sample. The result showed that palatability of formulation pellet bait with active hexaflumuron (14.33%) was higher than solid pine wood (6.58%). The formulation of pellet bait with 0.25% active hexaflumuron with presto pre-treatment was able to eliminate C. curvignathus termites.

Catching performance and catching efficiency of siliconized baits in hand line fishery

The present study investigated the catching performance and catching efficiency of natural mud shrimp (alive) (Upogebia pusilla), siliconized mud shrimp and siliconized pellet in handline fishing. The trials were performed in Kıyıkışlacık Village of Muğla province. The main body of the handline is Ø 0.50 mm, leader and snood are Ø 0.27-0.30 mm, the snood length and distance are 10 cm and 20 cm, respectively. Each handline has 3 hooks and the hook type is 4 no straight. Catches from natural mud shrimp, siliconized shrimp and siliconized pellet bait retained separately, sorted by species and weighed as. 0.01 g sensitivity and measured as the total length. Totally 590 individuals from 30 different species in total were caught including; 28 bony fish (93.33%), and 2 cephalopods (0.66%). While natural mud shrimp captured the 50.7% of fish, 44.7% and 4.6% were caught with siliconized mud shrimp and siliconized pellet, respectively. CPUE values of natural mud shrimp, siliconized shrimp and silicon pellet were calculated as 1.57 n/h, 1.38 n/h and 0.14 n/h, respectively. In addition, YPUE values were determined as 121.84 g/h, 137.73 g/h and 7.62 g/h for natural mud shrimp, siliconized shrimp and silicon pellet, respectively. Despite the fact that the number of individuals that a live mud shrimp catch in a unit of time is high, it was found out that the weight is more in a unit of time when silicone mud shrimp is used. It was concluded that using of siliconized mud shrimp has a high capacity of catching performance and catching efficiency and can be used as bait when natural mud shrimp cannot be utilized as alive or unable to be supplied, due to the weather conditions and time restrictions.

Size-susceptibility of Cornu aspersum exposed to the malacopathogenic nematodes Phasmarhabditis hermaphrodita and P. californica

ABSTRACT Slugs and snails are agricultural pests usually controlled by chemical bait pellets however an alternative method is the commercially produced malacopathogenic nematode Phasmarhabditis hermaphrodita, which is sold across northern Europe. P. hermaphrodita can kill several slug species but is unable to affect larger pestiferous snails. Therefore, we examined whether the closely related species Phasmarhabditis californica, isolated from the U.K. could kill neonate or adult common garden snails (Cornu aspersum). In our first experiment, neonate C. aspersum were exposed to 1000 nematodes per tube containing three strains of P. californica (designated DMG0017, DMG0018 or DMG0019) (as well as the commercial formulation of P. hermaphrodita DMG0001) and feeding inhibition and survival were monitored over 14 days. All nematodes apart from P. californica (DMG0017) killed the snails and caused feeding inhibition. In a follow up experiment we exposed adult C. aspersum to two doses (30 and 90 nematodes per cm2) of P. californica (DMG0019) and P. hermaphrodita (DMG0001) and monitored survival, feeding inhibition and changes in weight over 21 days. Neither nematode species affected survival, feeding inhibition or weight of the adult snails. In summary, P. californica (DMG0018 and DMG0019) are as pathogenic as P. hermaphrodita (DMG0001) and could be used to target neonate snails, however, the use of malacopathogenic nematodes to control large adult snails continues to be problematic.

Contact Efficacy of Different Wood Ashes against Spanish Slug, Arion vulgaris (Gastropoda: Arionidae)

The wood ash from seven plant species (sessile oak, European beech, European hornbeam, silver fir, European spruce, common alder, and Spanish chestnut) was tested against Spanish slug (Arion vulgaris) as an environmentally acceptable alternative to chemical bait pellets. We carried out laboratory and semi-field experiments to assess the contact and barrier efficacy of selected wood ash. To demonstrate the contact efficacy, slugs were rolled in the wood ash. Geochemical analysis of wood ash was carried out as well. The highest concentrations of chemical compounds SiO2, Al2O3, Fe2O3, MgO and MnO and elements Ba, Co, Cs, Ga, Cu, Pb and Zn were identified in the most effective ashes (beech, oak, fir, and spruce) compared to the ineffective ashes (hornbeam, chestnut, black ader). The concentration of cobalt was comparably higher, while the concentration of molybdenum was comparably lower in the four most effective wood ashes. The results of our studies revealed that the wood ash of oak and spruce have great contact efficacy. The oak and beech wood ash showed the strongest barrier efficacy against slugs. In the semi-field trials, only 10% of the plants treated with oak wood ash were damaged by slugs. The oak wood ash is an efficient alternative for slug control, however, further studies and biotechnical enhancement are needed.

Acute toxicity and clotting times of anticoagulant rodenticides to red-toothed (Odonus niger) and black (Melichthys niger) triggerfish, fathead minnow (Pimephales promelas), and largemouth bass (Micropterus salmoides).

Anticoagulant rodenticides (ARs) are used in rat eradication efforts on island wildlife refuges. AR bait pellets can get into coral reef areas during broadcasting and lead to exposure of non-target organisms, such as marine fishes. The objective of this study was to determine the sensitivity of representative saltwater fishes, Red-toothed triggerfish (Odonus niger) and Black triggerfish (Melichthys niger), and common freshwater fishes, fathead minnow (Pimephales promelas), and largemouth bass (Micropterus salmoides) to first generation ARs, diphacinone (DPN) and chlorophacinone (CPN), as well as a second-generation AR, brodifacoum (BROD). Acute toxicity of ARs was evaluated by single dose, intraperitoneal injections. The median lethal dose (LD50) ranges were 137−175 μg DPN/g, 155−182 μg CPN/g, and 36−48 μg BROD/g for Red-toothed triggerfish and 90−122 μg DPN/g, 125−164 μg CPN/g, and 50−75 μg BROD/g for black triggerfish. Laboratory surrogate test fish species fathead minnow and largemouth bass were of similar sensitivity toward AR-induced toxicity compared to triggerfish based on LD50 values. Sublethal effects on elevated clotting time occurred in dose-dependent fashion in all fish tested. Fish appear to have low sensitivity to AR chemicals as compared to other taxa, in particular mammals and birds, based on across-taxa comparisons of species sensitivity distributions of whole body, single dose acute lethality (LD50 values). The sensitivity of fish to waterborne exposures of ARs has yet to be fully evaluated and indeed may prove more hazardous to fish.

ПРАКТИЧЕСКАЯ ЦЕННОСТЬ ПИЩЕВОЙ ПРИМАНКИ ФЛАЙБЛОК® ГРАНУЛЫ ДЛЯ СНИЖЕНИЯ ЧИСЛЕННОСТИ ЗООФИЛЬНЫХ МУХ В УСЛОВИЯХ СВИНОФЕРМ

Bestial flies are widely spred at various types of livestock enterprises (dairy farms, fattening farms, pig farms, sheep farms, stud farms, poultry farms) of the Russian Federa-tion; they are mechanical and biological carriers of many pathogens of infectious and invasive diseases, can cause anemia and stress in productive farm animals and young animals. The economic damage from infec-tious and parasitic diseases, the causative agents of which carry licking and blood-sucking flies, as well as from a decrease in productivity due to stress, is measured in hundreds of millions of rubles a year. In addition, high costs are required for veteri-nary, anti-epizootic and recreational activi-ties. We conducted a test to study the effective-ness of the Flyblock® food pellet bait (organization-developer of NEC Agrovet-zashchita LLC), an insecticidal and attract-ant measurement during the period of the maximum number of bestial flies on a pig farm.The food bait was tested from the sec-ond half of summer until the end of Septem-ber in three commercial pig farms of the Ryazan Region: 50 x 12 m - experimental, 5 x 12 m - control № 1 (fodder kitchen), 50 x 12 m - control № 2. In the experimental room, the Flyblock® drug granules were distributed by the rate of 5 g per 5 m2 in cardboard containers 12 x 8 cm in size with 4 cm high side walls in plac-es not accessible to animals - window open-ings. The Flyblock® pellet food bait was placed once with regular monitoring (starting from the first day and for 2.5 months) of its effectiveness against bestial flies with the obligatory re-moval of dead flies. Studies have showed the high efficiency of Flyblock® food pellets against bestial flies. The effectiveness of the the drug against licking and bloodsucking flies when keeping pigs for fattening in the premises of a com-mercial pig farm is in almost all cases of research more than 95%.

Rodenticide efficacy in sewers in São Paulo, Brazil.

Rodents infest urban environments, causing damage and acting as vectors for disease transmission. Currently, anticoagulants are the most widely used chemical rodenticides, and their extensive and widespread use can contaminate the environment. To ensure effectiveness and avoid accumulation of rodent baits in the environment, it is important to evaluate how long rodent baits maintain their palatability and efficacy. In rodent control programs, rodent baits are placed in locations such as sewers, but after a few days, baits appear altered, causing doubts about the control efficacy. For this reason, baits are replaced periodically, which increases costs and generation of chemical waste. The objective of this study was to evaluate the palatability and efficacy of commercial paraffin-type rodent bait blocks placed in sewers in São Paulo City over a period of 90 days. Bait blocks were placed in sewers and collected after 30, 60, and 90 days. Additionally, in a laboratory two-choice test, wild-caught urban Norway rats were offered 40-60 g of bait and an equal volume of standard rat pellets. The amount of bait and rat pellet consumed was registered, the palatability was calculated, and the efficacy was measured as the percentage mortality over 14 days. The results showed that, even when they had an altered appearance, bait blocks remained palatable to the rats and were effective after at least 90 days. Leaving bait blocks for longer periods could be an effective strategy for reducing costs and could help to ensure the control of urban rodents in an environmentally sustainable way.

Do Workers from Subspecies Acromyrmex subterraneus Prepare Leaves and Toxic Baits in Similar Ways for Their Fungus Garden?

Toxic baits are the most efficient method to control leaf-cutter ants in eucalyptus forests for paper and cellulose production. For the proper use of these baits, insecticide compounds must reach workers and contaminate them. Thus, understanding how these baits are processed inside the nests is vital for a successful control, especially when it comes to genus Acromyrmex. Lack of information on toxic baits and on contamination of Acromyrmex workers raises the question: do workers from subspecies Acromyrmex subterraneus (Forel) prepare leaves and toxic baits in similar ways for their fungus garden? To answer it, this study described and analyzed the behavioral repertoire executed by A. subterraneus workers during the preparation of leaf disks and baits and their incorporation into the fungus garden. Results show that the act of licking the substrate was the most frequently executed behavior, regardless of subspecies or size categories. Moreover, additional behaviors have been observed when workers processed the baits, such as licking and scraping their jaws on the surface of the bait pellet, as well as licking and biting fragments of bait pellets, moistening them. Thus, it is concluded that the preparation of baits is different from that of leaves; baits are more processed and can therefore contribute to contaminating workers via insecticides.

Natural bait additives improve trapping success of common voles, Microtus arvalis

Common voles are serious pests in European agriculture, damaging cereals, rapeseed and other crops and causing substantial losses per outbreak. Not only might the usual approach of applying rodenticides for population management have disadvantages for non-target species, these rodenticides also cannot be used in organic farming. An alternative solution could be an approach related to the concept of ecologically-based rodent management combining environmentally sustainable methods based on knowledge about the target species. Such a method inhibits the dispersal of common voles from field margins to crop habitats via a trap-barrier system. However, little is known about attractants, which could increase the trapping success of common voles. We screened 22 natural substances in T-maze trials. The three most successful substances were further tested during enclosure trials under semi-natural conditions. Bisabolol, eugenol and maltol attracted six of eight voles during the T-maze trials and were mixed into grain pellet bait. Bait containing maltol caught significantly more common voles in enclosures than plain control bait or bait containing bisabolol or eugenol. Of all individuals, 21% chose exclusively baits with maltol. Generalized Linear Mixed Model (GLMM) indicated that every individual would be trapped once in 6 h with this bait type and GLMM predicted that 63% of females and 56% of males would choose this bait over plain control bait. Maltol bait could help either by more efficiently trapping common voles in a trap-barrier system or improving bait acceptance when rodenticides are applied.

Olfactory Dysfunction in Autoimmune Central Nervous System Neuroinflammation.

Olfactory dysfunction is an early sign of neuroinflammation of the central nervous system (CNS). Microgliosis and astrogliosis are representative pathological changes that develop during neuroinflammation of CNS tissues. Autoimmune CNS inflammation, including human multiple sclerosis, is an occasional cause of olfactory disorders. We evaluated whether gliosis and olfactory dysfunction developed in animals with experimental autoimmune encephalomyelitis (EAE), a model of human multiple sclerosis. Neuroinflammatory lesions characterized by infiltration of inflammatory cells and microglial cell activation were occasionally found in the olfactory bulbs of EAE-affected rats. Microglial activation, visualized by immunohistochemical staining of ionized calcium binding protein (Iba)-1, and astrogliosis in the olfactory bulb were also evident in the olfactory bulb of EAE rats. Inflammatory cells were found along the olfactory nerves and in the olfactory submucosa. Western blot analysis of olfactory marker protein (OMP) levels showed that OMP expression was significantly downregulated in the olfactory mucosa of EAE rats. On the buried food test, EAE-affected mice required significantly more time to find a bait pellet. Collectively, the results suggest that the olfactory dysfunction of EAE is closely linked to downregulation of OMP and the development of inflammatory foci in the olfactory system in an animal model of human multiple sclerosis.

Effectiveness of Snap-trapping, Goodnature A24 Automated Traps, and Hand-broadcast of Diphacinone Anticoagulant Baits to Suppress Invasive Rats (Rattus spp.) and Mice (Mus musculus) in Hawaiian Forest

Invasive rodents (rats and mice) commonly occur on islands and often damage natural resources largely by predation of native species. Suppressing invasive rodent populations and their damages is therefore a common practice in many parts of the Hawaiian Islands, and land managers such as the Army Natural Resources Program on Oahu often control rodent populations by using large-scale rat snap-trapping and Goodnature A24 automated rat traps (henceforth A24s). While rat traps can be effective at suppressing rat populations, mouse populations are not generally suppressed and may expand greatly. In an effort to reduce rodent populations to levels below that accomplished with rat traps alone at a 5-ha mesic forest on Oahu (Ohikilolo), we assessed the effectiveness of a one-time (two application) hand-broadcast of anticoagulant (Diphacinone-50) bait pellets applied at 13.8 kg/ha per application while A24s and rat snap-traps were active. We monitored rat and mouse activity during trapping and before, during, and after the bait applications using tracking tunnels, which are baited ink cards placed in tunnels so that foot prints of animal visitors can be identified. We found that rat trapping alone was effective at reducing rat populations but not the mouse population, and that the one-time hand-broadcast of diphacinone bait reduced both rat and mouse activity to 0% tracking for about 1 month. However, rat and mouse populations rebounded 2 months later to 15% rat tracking and 41% mouse tracking, which were roughly pre-treatment levels. Rat suppression using A24s at Ohikilolo appeared much more effective year-round than at a nearby 26 ha site (Kahanahaiki), though mouse suppression was poor at Ohikilolo relative to Kahanahaiki. The hand-broadcast of diphacinone bait at both Ohikilolo and Kahanahaiki was effective but short-lived, so repeated baiting during the seasonal peaks in rodent abundance and increasing the size of the buffer area would more likely protect target natural resources from rats and mice.