Responses of coffee berry borer, Hypothenemus hampei (Ferrari)(Coleoptera: Scolytidae), to vertical distribution of methanol: ethanol traps

Captures of the coffee berry borer (CBB) Hypothenemus hampei (Ferrari) were assessed in traps in the field. IAPAR designed traps [plastic bottles (2 L) lured with methanol:ethanol (1:1) in a vessel] were placed either at 0.5, 1.0 and 1.5m high from the ground or simultaneously tested in the 2004 fructification season. Traps placed at the three heights trapped 5.5 times more CBB than the others, mostly at the traps placed at 0.5 m (75%). Treatments using the IAPAR designed trap placed at 1.2 m high; IAPAR trap with a white plastic plate above (IAPAR modified I) at 1.2 m high; IAPAR at 0.5 m high and two additional vessels at 1.0 and 1.5m high (IAPAR modified II) and T-163 trap [three red plastic cups (300 ml) and a red plastic plate as a cover] lured with M:E (1:1) at 1.2m height were compared in the vegetative (2005) and fructification (2006) periods. IAPAR modified II (dispenser vessels placed at 0.5, 1.0 and 1.5 m) trapped more beetles than the remaining types (2.72 times more beetles than IAPAR design); and IAPAR modified I traps trapped more beetles than T 163 and IAPAR traps in the vegetative period. In the reproductive period, IAPAR modified II trapped less beetles than IAPAR and IAPAR modified I. In 2007 vegetative season, IAPAR modified II trap were compared with IAPAR trap and trapped 2.8 times more beetles. The positive responses to a vertical distribution of the volatile attractants in the vegetative period of the planting allow the development of more efficient trapping systems for CBB.     

Improved semiochemical-based trapping method for old-house borer, Hylotrupes bajulus (Coleoptera: Cerambycidae)

The old-house borer, Hylotrupes bajulus (Linnaeus) (Coleoptera: Cerambycidae), has been a very serious pest of structural timber in many parts of the world. The available semiochemical-based trapping method typically results in low capture rates. In this study, efforts were made to improve the semiochemical-based trapping method using screen cage assays conducted in the greenhouse. Ground traps baited with two vials of (3R)-ketol + 1-butanol (pheromone baited) caught >21.0% adults than the alternative trap and were seen to be superior to ramp traps baited with identical compounds. Based on adult catches with pheromone-baited traps with different colors, attraction of H. bajulus adults to black was significantly greater than other colors, followed by brown, gray and yellow, red, white, green, and blue. No differences were found in adult catches to pheromone-baited traps with respect to different trap sizes. There were no statistical differences between the different semiochemicals tested. Therefore, black ground traps baited with two vials of (3R)-ketol + 1-butanol plus two vials of ethyl acetate can be effective in the monitoring and potential control of H. bajulus.     

Female sex pheromone of brinjal fruit and shoot borer,Leucinodes orbonalis (Lepidoptera: Pyralidae): trap optimization and application in IPM trials

Delta and wing traps baited with synthetic female sex pheromone of Leucinodes orbonalis Guenée were found to catch and retain ten times more moths than either Spodoptera or uni-trap designs. Locally-produced water and funnel traps were as effective as delta traps, although 'windows' cut in the side panels of delta traps significantly increased trap catch from 0.4 to 2.3 moths per trap per night. Trap catch was found to be proportional to the radius of sticky disc traps in the range 5-20 cm radius, discs with a 2.5 cm radius caught no moths. Wing traps placed at crop height caught significantly more moths than traps placed 0.5 m above or below the crop canopy. Replicated integrated pest management (IPM) trials (3 x 0.5 ha per treatment) were conducted in farmers fields with young and mature eggplant crops. Farmers applied insecticides at least three times a week in all check and IPM plots. In addition pheromone traps were placed out at a density of 100 per ha and infested shoots removed weekly in the 0.5 ha IPM plots. Pheromone trap catches were reduced significantly from 2.0 to 0.4 moths per trap per night respectively in check and IPM plots in a young crop and 1.1 to 0.3 moths per trap per night in check and IPM plots respectively in a mature crop. Fruit damage was significantly reduced from an average of 41.8% and 51.2% in check plots of young and mature crops respectively to 22% and 26.4 respectively in the associated IPM plots. Significant differences in pheromone trap catches and fruit damage were attained four and two weeks respectively after IPM treatments began in the mature crop whereas in the immature crop significant differences were not observed for the first eight to nine weeks respectively. The relative impact of removing infested shoots and mass trapping on L. orbonalis larval populations was not established in these trials but in both cases there was an estimated increase of approximately 50% in marketable fruit obtained by the combination of control techniques compared to insecticide treatment alone.     

Distribution and dynamics of Japanese beetles along the Indianapolis Airport perimeter and the influence of land use on trap catch

As part of a program to minimize the accidental transportation of Japanese beetles (Popillia japonica) through cargo aircraft to areas where they are not established, a 4-yr trapping project was initiated to study the relative distribution and dynamics of the beetles along a trap line around the Indianapolis International Airport. Land use influence on beetle abundance (trap catch) was assessed using a geographic information system. Trap catch was consistently high in some locations and low in others. In general, high trap catches occurred near agronomic land planted with corn or soybeans, which are both preferred hosts of adult beetles. Low trap catches generally occurred in areas lacking preferred host plants. The amount of agronomic land within 500 m of the traps was always positively correlated with trap catch. Average trap catches were highly correlated by location from year to year, indicating stability of the relative distribution of the beetles along the trap line. Because high trap catches consistently occurred in the same locations, it can be inferred that trapping can be an effective method to monitor Japanese beetle populations. Taking airport-owned agronomic land out of corn and soybean production near the cargo terminals may reduce beetle activity in these areas.     

Visual Responses of Adult Asian Citrus Psyllid (Hemiptera: Liviidae) to Colored Sticky Traps on Citrus Trees

The effects of five differently-colored sticky traps in capturing adult Diaphorina citri were evaluated in citrus orchards. Trap catches of D. citri were monitored fortnightly on blue, green, red, white and yellow sticky cards placed on three citrus varieties during D. citri active flight period from April to July in south Texas. Evaluation of mean trap catches of each color by repeated measures analysis of variance produced three separate groups: yellow traps caught significantly more D. citri adults than the other four traps; red and green traps caught significantly more D. citri than blue and white traps, which were not significantly different. Although the number of adult psyllid captured on all trap types significantly increased with time during the trapping period, the performance of traps did not change with time. Trap catches were also significantly influenced by the citrus species; traps placed on lemon trees captured more D. citri than those placed on sweet orange and grapefruit, suggesting that plant preference exhibited by D. citri may influence the performance of traps. The ratio of trap reflectance between the 680 to 700 nm and the 450 nm was significantly correlated with total trap catches in all host species studied. Thus, this index was a good indicator of the attractiveness of adult D. citri to colored traps. Additionally, we compared the reflectance values of young versus mature flush shoots of the three host plants used in this study as related to densities of D. citri recorded in colored traps. We discussed the importance of visual cues in the host finding behavior of adult D. citri.     

Monitoring spruce web-spinning sawflies Cephalcia spp.: the correlation between trap catches and soil sampling

The web-spinning sawflies of the genus Cephalcia Panzer (Hymenoptera, Pamphiliidae) are usually monitored by sampling prepupae in soil and by catching adults with visual traps, including yellow sticky traps. However, adult catches have never been compared with the actual density of prepupae. In this paper, a relationship is presented between the catches of Cephalcia arvensis Panzer adults (mostly males) and the number of prepupae ready to emerge (pronymphs) in an outbreak area of spruce forest (Picea abies Karsten) in the Southern Alps (Asiago, Italy). A significant linear relationship between the logarithmic estimates of the two variables was found. The model includes a spatial autoregressive parameter because adult catches were spatially correlated. The relationship allows to know whether or not the defoliation threshold of 20 pronymphs/m2 in spring samples is being exceeded, based on the number of adults caught on yellow sticky traps (defoliation threshold of 14.26 adults/trap). The variance not explained by the model is probably due to the flight behaviour of adult males, to the low precision of the estimated pronymph density at low population levels, and to the attraction of males by few females that are trapped and remain alive. The model was validated in a large monitoring programme of undamaged alpine spruce forests and allowed detection of two newly infested stands out of six that were considered at risk of defoliation, because of adult catch exceeded the threshold. Low adult catches were always associated with absence of defoliation. Our conclusion is that trapping of adult sawflies is a cheaper and easier monitoring method than prepupae sampling in the soil. This makes earlier detection of outbreaks possible, and consequently more efficient control.     

Uraba lugens (Lepidoptera: Nolidae) in New Zealand: pheromone trapping for delimitation and phenology

A synthetic sex pheromone trapping survey of the leaf skeletonizer Uraba lugens Walker (Lepidoptera: Nolidae) demonstrated the unexpectedly widespread distribution of the insect across > 40,000 ha of urban Auckland, New Zealand. A survey of eucalyptus trees planted in parks and other public areas showed a significant spatial correlation between trap catch and breeding populations, validating the trap survey results. Traps in trees showing damage had four-fold higher catches than traps placed in undamaged or nonhost trees, and < 1% of damaged trees with traps failed to catch adult moths. Damage by larval feeding was correlated with male trap catch in the previous generation, offering good prospects for a pest management decision support system, provided that an economic threshold is developed. Catches increased by 3.4-fold in the same georeferenced trapping grid between November and December 2003 and between March and April 2004 across two generations, over the summer. A vertical transect showed that catches increased with height up to the top trap at 13 m (60% of mean tree height). Options for managing the insect will need to overcome the high rate of increase, the rate of spread, and the vertical distribution of the insect on tall eucalyptus trees.     

Examining Cuphea as a potential host for western corn rootworm (Coleoptera: Chrysomelidae): larval development

In previous crop rotation research, adult emergence traps placed in plots planted to Cuphea PSR-23 (a selected cross of Cuphea viscosissma Jacq. and Cuphea lanceolata Ait.) caught high numbers of adult western corn rootworms, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), suggesting that larvae may have completed development on this broadleaf plant. Because of this observation, a series of greenhouse and field experiments were conducted to test the hypothesis that Cuphea could serve as a host for larval development. Greenhouse-grown plants infested with neonates of a colonized nondiapausing strain of the beetle showed no survival of larvae on Cuphea, although larvae did survive on the positive control (corn, Zea mays L.) and negative control [sorghum, Sorghum bicolor (L.) Moench] plants. Soil samples collected 20 June, 7 July, and 29 July 2005 from field plots planted to Cuphea did not contain rootworm larvae compared with means of 1.28, 0.22, and 0.00 rootworms kg(-1) soil, respectively, for samples collected from plots planted to corn. Emergence traps captured a peak of eight beetles trap(-1) day(-1) from corn plots on 8 July compared with a peak of 0.5 beetle trap(-1) day(-1) on 4 August from Cuphea plots. Even though a few adult beetles were again captured in the emergence traps placed in the Cuphea plots, it is not thought to be the result of successful larval development on Cuphea roots. All the direct evidence reported here supports the conventional belief that rootworm larvae do not survive on broadleaf plants, including Cuphea.     

Stable fly (Stomoxys calcitrans: Diptera, Muscidae) trap response to changes in effective trap height caused by growing vegetation

Stable flies (Stomoxys calcitrans L.) are blood-feeding pests of cattle, whose populations are often monitored using sticky traps. Trap responses at different heights were compared with: 1) a choice and no-choice test, with sticky cards set at 30 and 121 cm heights (above ground), and 2) tall (120 cm) traps placed in short (3 cm) and tall (40 cm) grass to assess how vegetation height affects trap catches. In the first experiment, the percentage of upper to lower trap catches were similar at choice (16%) and no-choice traps (15%). In the vegetation study, stable fly catch height data were fitted to gamma distributions to determine the most productive trap heights; 20 cm above short grass and 24 cm above tall grass (from lower edge of trap). The results indicate that traps used to monitor stable fly populations should be maintained at a constant distance above surrounding vegetation rather than ground surface, otherwise trap data can be misleading.     

Comparison of pheromone-mediated mating disruption and conventional insecticides for management of tufted apple bud moth (Lepidoptera: Tortricidae)

Large-plot studies were used to compare pheromone-mediated mating disruption and conventional insecticide applications for management of tufted apple bud moth, Platynota idaeusalis (Walker), in North Carolina in 1993 and 1994. Pheromone trap catches were reduced in mating disruption blocks, and traps placed in the lower stratum of the canopy had a higher level of trap capture reduction compared with traps placed in the upper stratum. First-generation tufted apple bud moth exposure to either pheromones for mating disruption or insecticides affected second generation pheromone trap catches in the lower and upper canopy. More second generation male moths were caught in pheromone traps placed in the upper compared with the lower canopy in blocks treated with pheromones for mating disruption during the first generation, whereas the opposite was true in blocks treated with insecticides during the first generation. Despite reduced trap catches in pheromone-treated blocks, egg mass densities were not reduced in these blocks compared with insecticide-treated blocks. Furthermore, fruit damage was not significantly different between mating disruption blocks and conventionally treated blocks in orchards with relatively low populations of tufted apple bud moth, but damage was greater in mating disruption blocks in orchards with higher moth densities.     

Efficacy of CC traps and seasonal activity of adult Bemisia argentifolii (Homoptera: Aleyrodidae) in Imperial and Palo Verde Valleys, California

Adult whitefly Bemisia argentifolii Bellows & Perring trap (CC trap) catches were compared with suction type trap catches. CC trap catches were significantly correlated to the suction trap catches. Higher numbers of B. argentifolii adults were caught in CC traps oriented toward an untreated, B. argentifolii-infested, cotton field as compared with traps oriented toward Bermuda grass fields, farm roads, or fallow areas. CC trap catches at five heights above ground (from 0 to 120 cm) were significantly related to each other in choice and no-choice studies. CC trap catches were low in the Imperial and Palo Verde Valleys from late October to early June each of 1996, 1997, and 1998. Trap catches increased with increasing seasonal air temperatures and host availability. Trap catches were adversely affected by wind and rain. Abrupt trap catch increases of 40- to 50-fold for 1-2 d in late June to early July followed by abrupt decreases in adult catches suggest migrating activity of adults from other nearby crop sources.     

Studies on the effectiveness of coroplast sticky traps for sampling stable flies (Diptera: Muscidae), including a comparison to Alsynite

Stable flies, Stomoxys calcitrans (L.) (Diptera: Muscidae), are a blood-feeding pest of cattle worldwide. A new trapping material, Coroplast, was compared with Alsynite sticky traps based on the number, sex, and parity of stable flies caught. Coroplast sticky traps caught more stable flies than Alsynite (trap catches of 2384 versus 753 on 15 traps), with this increase attributed to catching more males (1531 versus 532) and nulliparous females (817 versus 175); parous catches were similar (36 versus 46). The spectral reflectance of Alsynite and Coroplast sticky traps is reported. We also examine Coroplast traps in detail with respect to trap color. Although clean sheets of Alsynite had a higher solar reflectance than Coroplast (90 versus 82% at 450 nm), Coroplast with debris had a higher reflectance than debris-covered Alsynite (62 versus 30% at 450 nm). White Coroplast was most effective, followed by closely by gray. Black and blue were the least effective trapping colors.     

An effective strategy for trapping Douglas-fir beetle, Dendroctonus pseudotsugae (Col., Scolytidae) using combinations of unbaited and pheromone baited funnel traps

Experiments were conducted to confirm and quantify earlier observations that unbaited funnel traps in conjunction with pheromone baited funnel traps may substantially increase trap catches of Douglas-fir beetles, Dendroctonus pseudotsugae . In 12 replicates of one of these experiments during 1998 and 1999, the catches of a single baited control trap were compared to those of a set of four traps where the central trap was baited and a ring of three traps, 1 m from the central trap arranged in a star configuration, were unbaited. In the second experiment conducted during 1999, a ring of three unbaited traps was placed at 2 m and a second at 5 m from the central baited trap. Statistically robust results demonstrated clearly that the configuration of one central baited trap plus three unbaited satellite traps collected twice as many beetles on average over the season compared to the baited control trap. Addition of a second ring of unbaited traps increased collections by only about 20%, but this experiment indicated that trap catches dropped off exponentially with distance from the centre. The number of beetles caught in the baited traps was essentially the same in all 3 arrangements, suggesting that the additional unbaited traps captured beetles that otherwise may not have been captured.     

Dispersal of adult European corn borer (Lepidoptera: Crambidae) within and proximal to irrigated and non-irrigated corn.

The European corn borer, Ostrinia nubilalis (Hübner), causes economic damage to corn, Zea mays L., throughout the Corn Belt. Because this insect has become the primary target of Bacillus thuringiensis Berliner (Bt) transgenic corn, current efforts addressing the management of O. nubilalis resistance to Bt corn require information on adult European corn borer dispersal and factors affecting its dispersal. In 1998 we conducted mark-release-recapture, release-recapture, and caged-mating studies to directly measure and compare local dispersal patterns of O. nubilalis adults within and proximal to irrigated and non-irrigated cornfields. Releases of marked adults were made corresponding to the first and second flight of O. nubilalis in eastern Nebraska. Adult dispersal was significantly different between irrigated and non-irrigated cornfields. Released adults tended to remain in and near irrigated cornfields, but dispersed out of and away from non-irrigated cornfields. When released at the edge of the cornfield, neither male nor unmated female O. nubilalis displayed an initial tendency to move out of irrigated corn and into the mixed smooth bromegrass (Bromus inermis Leyss) and broadleaf-weed field edge. Mating efficiency in a late-season cornfield was not significantly different than in dense foxtail (Setaria spp.). Generally, we found that adult O. nubilalis dispersal may vary depending on variables such as action-site availability and agronomic practices and their interaction with O. nubilalis life history.     

Performance of irradiated Teia anartoides (Lepidoptera: Lymantriidae) in urban Auckland, New Zealand

The Australian moth Teia anartoides Walker has been the target of a major eradication program in Auckland, New Zealand. Information on cold torpor and dispersal was needed to help interpret catches of sterile and wild males in female-baited delta traps operated in a grid of up to 1,696 traps at 500-m spacings across the city. Laboratory experiments indicated male flight was enabled at temperatures above 17 degrees C (confirmed by field trapping of wild and recaptured moths). Male survival in the field or in field cages was determined to be limited to approximately 4 d. Sterilization of males for dispersal studies was achieved by exposing male pupae to either 160 or 100 Gy by using 1.25 MeV gamma rays from a Cobalt source, before release as fluorescent-dyed emerged adults. Dispersal was determined by recapture of males in the trapping grid of 1,696 delta traps baited with virgin female moths and placed at spacings of 50-500 m. Irradiated sterile males dispersed up to a maximum recorded distance of 4,500 m (160 Gy) and 10,000 m (100 Gy). At 100 Gy, the median dispersal distance was 300 m, with 90% of males dispersing 1,600 m or less.     

Small‐plot studies comparing pheromone and juice baits for mass‐trapping invasive Synanthedon myopaeformis in Canada

Recent introduction of Synanthedon myopaeformis (Borkhausen) (Lepidoptera: Sesiidae) into organic apple‐growing areas of Canada has stimulated research on semiochemical‐based management of this European pest. Replicated, small‐plot (0.16 ha) experiments were conducted to compare sex pheromone, 3Z,13Z‐octadecadienyl acetate (10 mg), Concord grape juice (300 ml), or their combination, as mass‐trapping lures at trap densities equivalent to 12.5, 25, 50, and 100 traps ha^?1. Total numbers of male and female moths removed from test plots increased significantly with trap density in all juice‐based mass‐trapping experiments. In pheromone mass‐trapping experiments, however, total catches of males did not increase significantly as trap densities were increased and catches appeared to plateau with 25–50 traps ha^?1. With pheromone‐based mass‐trapping, significantly fewer males were caught in pheromone‐baited assessment traps at the centre of each mass‐trapping plot than in identical traps in untreated plots. This reduction is indicative of significant trap interference or trap ‘shut‐down’. Increasing the density of juice‐based mass‐trapping had no effect on catches of male or female moths in juice‐baited assessment traps, indicating a short range of attraction and lack of interference between juice traps. Pheromone‐ and juice‐based mass trapping removed similar numbers of males at each trap density tested, respectively, but summed catches of males and females were greatest with juice baits. Combining pheromone and juice into a single mass‐trapping treatment (50 traps ha^?1) did not significantly increase catches of males or females relative to either treatment alone. If a practical bisexual mass‐trapping system is going to be developed for S. myopaeformis, then identification of volatile kairomones in Concord grape juice may be useful.     

Influence of wind conditions and intertrap spacing on pheromone trap catches of male european pine sawfly,Neodiprion sertifer

The spatial distribution of catches of male European pine sawfly,Neodiprion sertifer (Geoffr.) (Hymenoptera, Diprionidae), was studied using different pheromone trap arrays. In hexagonal trap groups, trap interference was evident by reduced catch in the central of seven traps spaced 10 to 40 m apart. When the trap spacings were either 5 or 80 m no significant reduction could be shown. The interaction was more pronounced for strong (100 μg) pheromone ([2S, 3S, 7S]-3,7-dimethyl-2-pentadecanyl acetate) lures than for weak ones (10 μg). Similarly, the inner traps caught less than the outer traps in grids of 6×6 traps spaced 20 or 50 m apart. Mark-release-recapture experiments in the grid array confirmed that a majority of the males originated from outside the trap group and were caught in the first trap they encountered. There were no differences between catches in downwind, crosswind and upwind traps. Thus, no ‘overshooting’ was evident during average conditions, i.e. the sawflies did not divert from the trap initially attracting them by flying to the upwind trap. However, the proportion caught in the upwind traps increased with increasing wind velocity, suggesting more overlapping pheromone plumes at higher wind speeds. Also, the recapture rate of released males increased with increasing wind velocity up to a daily average of 3.1 m/s at 2m, indicating that sawflies more easily find the pheromone source, probably due to a more stable pheromone puff trajectory during higher wind velocities. The application of pheromone traps in e.g. monitoring studies is discussed and a distance of at least 50 m between the traps with strong lures used in the present study is recommended to avoid trap interaction.     

Effect of trap type, trap color, trapping location, and pheromone dispenser on captures of male Palpita unionalis (Lepidoptera: Pyralidae)

Field studies were conducted to evaluate the influence of trap design, trapping location, type of pheromone dispenser, and trap color on the capture of Palpita unionalis (Hübner) males, in olive groves. The experiments were carried out in two regions, Alexandria (northern Greece) and Oropos (central Greece), where olives are cultivated. In both regions, the majority of the males (> 70% of the total) were caught from late autumn to early winter, whereas < 1% was caught during July and August. Among the trap types used, the Funnel was significantly more attractive than Delta, Pherocon 1C, and Pherocon II traps. More males were caught in traps placed at the periphery of the groves than those placed in the center. Among the four colored traps tested, white traps were the most effective. However, a significant difference in trap catches was found between white and brown traps. Traps baited with red rubber septa captured more males than those baited with the white one. The use of these parameters in monitoring and managing P. unionalis is discussed.     

Spatio-temporal dynamics of corn rootworm, Diabrotica spp., adults and their spatial association with environment

Multiyear and multilocation studies were conducted to investigate the within‐ and the between‐year spatial dynamics of corn rootworms Diabrotica spp. (Coleoptera: Chrysomelidae), adults and their spatial associations with environmental factors in cornfields. Grid‐based spatial sampling was conducted by trapping adults emerging from the soil (i.e., ‘emergence‐trap counts’) and by counting the number of adults in the ear zone of corn plant (i.e., ‘ear‐zone count’). Spatial analysis with distance indices (SADIE) was used to determine spatial distribution patterns and to investigate spatial associations. Ear‐zone counts and emergence‐trap counts were spatially dynamic within a year and more frequently aggregated in the middle of growing seasons and random early and late in the season. However, during the peak population periods, spatial distribution of ear‐zone counts and emergence‐trap counts were significantly consistent between years, indicating predictability of future spatial distributions. Spatial distribution of emergence‐trap counts and ear‐zone counts were positively associated with soil moisture and presence of corn plants with silks, respectively. This study demonstrated that within‐year spatial distribution patterns were dynamic and that there was between‐year spatial consistency of corn rootworm adult distributions. Such information can be used to improve preventative management of corn rootworms.     

The influence of trap type on evaluating population structure of the semifossorial and social rodent <Emphasis Type="Italic">Octodon degus</Emphasis>

Trap type may influence captures of individuals in different age-sex categories in small mammal studies, resulting in biased population and demographic information. We deployed 4 live trap types at burrow systems of the rodent, Octodon degus Molina, 1782, in central Chile to determine trap efficacy in capturing individuals of 6 demographic categories. We captured 2672 individuals in 17 709 trap days (15.1% trapping success). Tomahawks were the most efficient trap capturing half of individuals during both years, followed by mesh Sherman traps, large Sherman traps, and medium Sherman traps in 2005. All trap types equally sampled sexes. Large and medium Sherman traps provided similar demographic structure, where half of the individuals captured were pups; Tomahawk traps sampled more adults than pups. Relative captures of pups were similar across different trap types, suggesting that pups are equally sampled by each of the deployed trap types. Relative captures of adults were lower in Sherman traps, suggesting that this age class avoided solid-walled traps. For Octodon degus, the sole use of Tomahawk traps may produce sufficient, unbiased demographic data. Only 4 trap mortalities occurred (0.15%). Researchers may minimize trap mortality without compromising sufficient demographic sampling by trapping during peak animal activity.