Development of underground detection system using a metal detector and aluminum tag for, Copris ochus (Coleoptera: Scarabaeidae).

Tracking of soil-dwelling insects poses greater challenges compared to aboveground-dwelling animals in terrestrial systems. A metal detector system consisting of a commercially available detector and aluminum tags was developed for detecting dung beetle, Copris ochus Motschulsky (Coleoptera: Scarabaeidae). First, detection efficacy of the system was evaluated by varying volumes of aluminum tags attached on a plastic model of the insect and also by varying angles. Then, detection efficacy was evaluated by varying depths of aluminum-tagged models under soil in 2 vegetation types. Finally, the effects of tag attachment on C. ochus adults were assessed for survivorship, burrowing depth, and horizontal movement. Generally, an increase in tag volume resulted in greater detection distance in semi-field conditions. Maximum detection distance of aluminum tag increased up to 17 cm below soil surface as the tag size (0.5 × 1.0 cm [width × length]) and thickness (16 layers) were maximized, resulting in a tag weight of 31.4 mg, comprising ca. 9% of average weight of C. ochus adult. Furthermore, the detection efficacy did not vary among angles except for 90°. In the field, metal detectors successfully detected 5 aluminum-tagged models in 20 × 10 m (W × L) arena within 10 min with detection rates ≥85% for up to depth of 10 cm and 45%-60% at depth of 20 cm. Finally, aluminum tagging did not significantly affect survivorship and behaviors of C. ochus. Our study indicates the potential of metal detector system for tracking C. ochus under soil.

Dispersal and oviposition patterns of Lycorma delicatula (Hemiptera: Fulgoridae) during the oviposition period in Ailanthus altissima (Simaroubaceae).

The spotted lanternfly (SLF), Lycorma delicatula (Hemiptera: Fulgoridae), has the potential to become a global pest and is currently expanding its range in the United States. In this study, we investigated the dispersal patterns of SLF in Ailanthus altissima during its oviposition period in South Korea using a fluorescent marking system. Oviposition patterns of SLF were then analyzed by surveying egg masses in A. altissima patches. The recapture rate of fluorescent-marked SLF rapidly decreased to 30% within the first two weeks. During the oviposition period, seven cases of among-patch dispersal of SLF adults were observed. The minimum distance that SLF could have traveled to achieve these among-patch dispersal events ranged from 10 to 1740 m, with most events spanning under 60 m. Also, the number of A. altissima trees on which fluorescent marked SLF were detected increased until September. Based on the egg mass survey, a total of 159 egg masses were detected from 38 out of 247 A. altissima trees. Furthermore, 79.2% of egg masses were located < 2.5 m above the ground. Finally, a generalized linear mixed model showed that tree height and diameter at root collar (DRC) of A. altissima trees had significant effects on the number of egg masses.

Characterization of overwintering sites of Haemaphysalis longicornis (Acari: Ixodidae) and tick infection rate with severe fever with thrombocytopenia syndrome virus from eight provinces in South Korea.

Haemaphysalis longicornis (Acari: Ixodidae) is an important vector of pathogens causing tick-borne diseases such as severe fever with thrombocytopenia syndrome (SFTS) in eastern Asia. Although an understanding of the overwintering ecology of ticks is fundamental to management of this vector, its winter biology remains unclear. Therefore, we conducted a field survey from eight provinces in South Korea to characterize overwintering sites of H. longicornis and investigate their SFTS virus infection rates. First, we conducted flagging which consists of horizontal sweeping of a 1 m2 cloth back-and-forth to collect ticks that may exhibit questing behaviors in four different landscapes: grassland, shrub, coniferous forest, and deciduous forest. From 640 sweeps of flagging (where each sweep covered 3.8 m2), we collected five unfed ixodid ticks. However, H. longicornis was not found. After the flagging, to locate overwintering ticks, we inspected a total of 679 samples consisting of three different structures: ground (leaf litter, soil surface, and topsoil layer), rocks, and dead trees. From the samples inspected, 85 unfed overwintering ixodid ticks were found. Haemaphysalis longicornis was the dominant species (88 %), and mostly nymphs were collected (94 %). This species was collected from ground samples, especially from the topsoil layer. Most H. longicornis were found in herbaceous landscapes such as grassland (46 %) and shrub (52 %). SFTS virus was found in 3 out of 38 pools of unfed nymphs (minimal infection rate: 4 %). Our results can serve as baseline information for the development of vector management programs.

Seasonal Occurrence of Haemaphysalis longicornis (Acari: Ixodidae) and Haemaphysalis flava, Vectors of Severe Fever With Thrombocytopenia Syndrome (SFTS) in South Korea.

The seasonal abundance of Haemaphysalis longicornis Neumann and H. flava Neumann (Acari: Ixodidae) was monitored from 2015 through 2017 in Gyeonggi-do, South Korea. The hard ticks were surveyed monthly using CO2 bait traps from April to November and flagging from July to September in a coniferous forest, a deciduous forest, shrubs, and a grassland vegetation types. Haemaphysalis longicornis and H. flava were most abundant in the grassland and shrubs, which yielded over 50% of the total number of ticks in all 3 yr. Furthermore, H. longicornis comprised up to 90% of the ticks collected. Generally, peaks of nymph, adult, and larva numbers were observed from April to June, from June to July, and from August to September, respectively. Half of the ticks were pooled and tested for the presence of the SFTS virus with negative results.

Assessment of potential effects and detection efficacy of a fluorescent marking system on a medically important hard tick, Haemaphysalis longicornis (Acari: Ixodidae).

BACKGROUND: Although Haemaphysalis longicornis (Acari: Ixodidae) is an important disease vector, its small size restricts the tracking methods applicable. Recently, fluorescent marking as a conventional detection method for small arthropods has been improved by combining it with an ultraviolet laser. We examined the application potential of this new fluorescent marking system (FMS) for tracking H. longicornis by evaluating the effect of fluorescent marking on the ticks and detection efficacy. RESULTS: Under laboratory conditions, fluorescent marking did not significantly affect the survivorship, movement patterns, and CO2 response of H. longicornis at all three developmental stages. Fluorescent-marked individuals could be detected at distances ranging from 12 to 29 m under dark, increasing with the body size. Finally, in grassland, >90% of fluorescent-marked individuals were retrieved at night regardless of developmental stage. However, the overall detection rate (<42%) was substantially reduced during the day. CONCLUSIOIN: Our results show that FMS can reliably detect H. longicornis at night. Nevertheless, fluorescent-marked individuals are not as conspicuous under sunlight when they are illuminated with ultraviolet lasers, limiting the use of FMS during the day. Therefore, the development of an alternative tracking method is warranted for an effective detection of ticks during the day. © 2019 Society of Chemical Industry.

Evaluating the efficacy of two insect detection methods with Riptortus pedestris (Hemiptera: Alydidae): portable harmonic radar system and fluorescent marking system.

BACKGROUND: Although portable harmonic radar system and fluorescent marking system are two widely used detection methods, their comparative effectiveness has not been studied. Therefore, we first tested the applicability of fluorescent marking system on Riptortus pedestris (Hemiptera: Alydidae). Then, we evaluated the efficacy of the two methods used either alone or combined in a grass field and bean field, varying with complexity, during day and night. RESULTS: Fluorescent marking did not affect the behavior or fitness of Riptortus pedestris except for vertical walking, while allowing the detection from >25 m when paired with a handheld laser. Generally, the portable harmonic radar system and both methods combined were more successful in sample detection, although the fluorescent marking system in the bean field at night was as competitive as the two. Combining both methods made sample retrieval easier at night than the portable harmonic radar system. Nevertheless, the total detection time showed a large variance across the methods. CONCLUSION: The portable harmonic radar system can be an effective detection method in either landscape during both day and night. Furthermore, the fluorescent marking system can be a reliable tool at night as well. Lastly, combining both methods can improve the night detection. © 2018 Society of Chemical Industry.