Harmonic radar: assessing the impact of tag weight on walking activity of Colorado potato beetle, plum curculio, and western corn rootworm

Behavioral Effects and Retention of Protein Immunomarkers on Plum Curculio Conotrachelus nenuphar (Coleoptera: Curculionidae)

Protein immunomarking can be used to track the dispersal of insects in the field or identify plant-insect interactions. By marking insects with known proteins and recapturing them, their movement or host use can be quantified with Enzyme Linked Immunosorbent Assay (ELISA). Before using this technique, retention and behavioral effects of these markers should be evaluated to ensure that the insect's natural behaviors are conserved. Here, we tested the effects of protein markers on the plum curculio, Conotrachelus nenuphar (Coleoptera: Curculionidae) using two different application methods. This weevil is native to North American and a pest of tree fruit and blueberry in the United States and causes damage resulting in near complete crop loss if left untreated. We tested the effects of marking adult C. nenuphar with two inexpensive food-based immunoprotein markers, bovine casein (cow's milk) and chicken albumin (egg whites) on climbing distance (total cm), lateral movement (total cm), and lateral movement speed (cm/s), as well as retention time of protein immunomarkers. Neither protein immunomarker affected C. nenuphar movement or climbing, although females climbed significantly greater distances than males. ELISA assays detected 37.5-56.2% of milk protein and 56.2-59.3% of egg on the insect 7 d after application depending on application method. Our findings indicate that food-based protein immunomarkers can be used in future studies to test C. nenuphar movement within host plants without impacting behavior. The use of protein immunomarking will allow studies that will lead to behaviorally based management tactics.

Estimating the effect of tracking tag weight on insect movement using video analysis: A case study with a flightless orthopteran

In this study, we describe an inexpensive and rapid method of using video analysis and identity tracking to measure the effects of tag weight on insect movement. In a laboratory experiment, we assessed the tag weight and associated context-dependent effects on movement, choosing temperature as a factor known to affect insect movement and behavior. We recorded the movements of groups of flightless adult crickets Gryllus locorojo (Orthoptera:Gryllidae) as affected by no tag (control); by light, medium, or heavy tags (198.7, 549.2, and 758.6 mg, respectively); and by low, intermediate, or high temperatures (19.5, 24.0, and 28.3°C, respectively). Each individual in each group was weighed before recording and was recorded for 3 consecutive days. The mean (± SD) tag mass expressed as a percentage of body mass before the first recording was 26.8 ± 3.7% with light tags, 72 ± 11.2% with medium tags, and 101.9 ± 13.5% with heavy tags. We found that the influence of tag weight strongly depended on temperature, and that the negative effects on movement generally increased with tag weight. At the low temperature, nearly all movement properties were negatively influenced. At the intermediate and high temperatures, the light and medium tags did not affect any of the movement properties. The continuous 3-day tag load reduced the average movement speed only for crickets with heavy tags. Based on our results, we recommend that researchers consider or investigate the possible effects of tags before conducting any experiment with tags in order to avoid obtaining biased results.

Characterizing and Simulating the Movement of Late-Instar Gypsy Moth (Lepidoptera: Erebidae) to Evaluate the Effectiveness of Regulatory Practices

The European gypsy moth, Lymantria dispar L., is an invasive insect in North America that feeds on over 300 species of trees and shrubs and occasionally causes extensive defoliation. One regulatory practice within quarantine zones to slow the spread of this insect recommends that wood products (e.g., logs, pulpwood) originating from quarantine areas are staged within 100 foot-radius buffer zones devoid of host vegetation before transport outside the quarantine boundary. Currently, there are little data underpinning the distance used. We conducted field experiments in Wisconsin to assess buffer zone efficacy in reducing risk of larval gypsy moth encroachment on wood staging areas. We released late-instar gypsy moth larvae in groups around the perimeter of a 100-ft radius zone and tracked their movements for 10-h periods using harmonic radar and tested whether host vegetation staged around the perimeter or food availability before release altered movement patterns. Three larvae moved over 300 ft in 10 h, but 93% of larvae moved <100 ft total. The presence of host vegetation reduced the likelihood of larvae entering the buffer zone by 70%. Food availability before release did not affect movement. Using these field data, we parameterized a Monte Carlo simulation model to evaluate risk of larvae crossing zones of different sizes. For zones >100 ft in radius, <4% of larvae reached the center. This percentage decreased as zone size increased. Implications of these results for the regulatory practices of the gypsy moth quarantine are discussed.

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.

Harmonic radar tagging for tracking movement of Nezara viridula (Hemiptera: Pentatomidae)

Harmonic radar tagging was investigated as a method for monitoring the movement of the southern green stink bug, Nezara viridula (L.) (Hemiptera: Pentatomidae). Because adhesive toxicity and tag weight limit the use of this technology, initial efforts focused on selection of the optimal adhesive and design of harmonic radar tags to reduce impact on the movement of stink bugs. A design consisting of a 6-cm-long 0.10-mm-thick silver-plated copper monopole on the anode terminal of a three-contact Schottky barrier diode attached with Gorilla super glue provided a compromise between unimpaired movement and tracking range, adding an additional 8% to the weight of the stink bug while not significantly (P > 0.05) reducing walking or flying mobility in the laboratory. Recovery of tagged stink bugs in cotton, Gossypium hirsutum (L.), and fallow fields ranged from 10 to 75% after 24 h, whereas marked stink bugs were recovered at rates of 0-35% by using sweep net or drop cloth sampling. The distance dispersed in the field was not impacted (P > 0.05) by crop, tagged status, or gender of the insect. Future research should examine possible improvements to the harmonic radar transceiver and the wire antenna to decrease encumbrance.

Effectiveness of glues for harmonic radar tag attachment on Halyomorpha halys (Hemiptera: Pentatomidae) and their impact on adult survivorship and mobility

We evaluated the effectiveness of three cyanoacrylate glues (trade names: Krazy [Elmer's Products Inc., Westerville, OH], Loctite [Henkel Corporation, Rocky Hill, CT], and FSA [Barnes Distribution, Cleveland, OH]) to attach harmonic radar tags securely on adult Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) and quantified the effect of the radar tag attachment on insect survivorship and mobility. In the laboratory, the strength of the glue bond between the radar tag and H. halys pronotum was significantly increased when the pronotum was sanded to remove cuticular waxes. The adhesive bond of the radar tag to the sanded pronotum of H. halys had strength of 160-190-g force and there was no significant difference among the three types of glue tested. The three glues had no measurable effect on the survivorship of radar-tagged H. halys over 7 d, compared with untagged insects. Over a 7-d period in the laboratory, horizontal distance traveled, horizontal walking velocity, and vertical climbing distance were all unaffected by the presence of the tags regardless of glue. A field experiment was conducted to compare the free flight behavior of untagged and radar-tagged H. halys. Adults were released on a vertical dowel and their flights were tracked visually up to ≍200 m from the release point. There was no significant difference in take-off time or in flight distance, time, or speed between untagged and radar-tagged individuals. In addition, prevailing flight direction was not significantly different between untagged and radar-tagged individuals. The absence of measurable impact of the radar tag attachment on H. halys survivorship or mobility validates the use of harmonic radar tags to study the dispersal ecology of this insect in field conditions.

Dispersal of Warren root collar weevils (Coleoptera: Curculionidae) in three types of habitat

Warren root collar weevil, Hylobius warreni Wood, is a native, flightless insect distributed throughout the boreal forest of North America. It is an emerging problem in young plantings of lodgepole pine, Pinus contorta variety latifolia, in western Canada, where larval feeding can kill young trees by girdling the root collar. Susceptible plantings are becoming more abundant following salvage harvesting and replanting activities in the wake of an ongoing epidemic of mountain pine beetle, Dendroctonus ponderosae (Hopkins). Previous studies using mark-trap-recapture methods found that movement rates of adult H. warreni were elevated in areas with high numbers of dead trees, consistent with a hypothesis that the insects immigrate from stands with high mountain pine beetle-caused tree mortality to young plantings in search of live hosts. Sampling methods were necessarily biased to insects captured in traps; however, potentially missing individuals that had died, left the study area, or simply remained stationary. Here, we used harmonic radar to examine weevil movement in three different habitats: open field, forest edge, and within a forest. We were able to reliably monitor all but two of 36 insects initially released, over 96 h (4 d). Weevils released in the open field had the highest rates of movement, followed by weevils released at the forest edge, then weevils released within the forest. Movement declined with decreasing ambient air temperature. Our results suggest that weevils tend to be relatively stationary in areas of live hosts, and hence may concentrate in a suitable area once such habitat is found.

Harmonic radar: efficacy at detecting and recovering insects on agricultural host plants

BACKGROUND

In pest management research, harmonic radar systems have been largely used to study insect movement across open or vegetation-poor areas because the microwave signal is attenuated by the high water content of vegetation. This study evaluated whether the efficacy of this technology is sufficient to track insects in vegetative landscapes.

RESULTS

Field efficacy data were collected using portable harmonic microwave radar and electronic dipole tags mounted on adults of three economically important pests: Leptinotarsa decemlineata (Say), Diabrotica virgifera virgifera (LeConte) [corrected] and Conotrachelus nenuphar Herbst. Detection and recovery of tagged Colorado potato beetles, plum curculios and western corn rootworms was high within and among potato plants, moderate within apple trees and high within, but not between, corn plants respectively. The efficacy of the radar depends on the ability of the operator to move around the host, scanning for a signal 'sightline' with the tagged insect among plant structures.

CONCLUSION

The detection rate of tagged insects by harmonic radar systems is high enough to track the walking path of pests through low row crops such as potato, tall row crops such as corn or tall but well-separated trees of orchard-type crops by adapting the scanning procedure to the vegetative architecture.

Evaluation of tag entanglement as a factor in harmonic radar studies of insect dispersal

The observation of insects and other small organisms entangled in the habitat after the addition of vertical or trailing electronic tags to their body has generated concerns on the suitability of harmonic radars to track the dispersal of insects. This study compared the walking behavior of adult Colorado potato beetle (Leptinotarsa decemlineata (Say) Chrysomelidae), plum curculio (Conotrachelus nenuphar (Herbst) Curculionidae), and western corn rootworm (Diabrotica virgifera virgifera (LeConte) Chrysomelidae) with and without vertical and or trailing tags in field plots or arenas. The frequency of the larger Colorado potato beetles crossing bare ground or grassy plots was unaffected by the presence of an 8 cm trailing harmonic radar tag. However, plum curculios and western corn rootworms, were either unable to walk with a 4 cm trailing tag (plum curculio) or displayed a reduced ability to successfully cross a bare ground arena. Our results revealed the significant impact of vegetation on successful insect dispersal, whether tagged or not. The vertical movement of these insects on stems, stalks, and tubes was also unaffected by the presence of vertical tags. Trailing tags had a significant negative effect on the vertical movement of the western corn rootworm. Results show that harmonic radar technology is a suitable method for studying the walking paths of the three insects with appropriate tag type and size. The nuisance factor generated by appropriately sized tags was small relative to that of vegetation.