Artificial Nests Research Articles

Fluctuating population density of the goby Lubricogobius exiguus during the breeding season with artificial nests at Oto Beach, Kagoshima, southern Japan

AbstractCryptobenthic reef fish (CRF), which are benthic reef fish with body lengths of less than 50 mm, generally exhibit life history characteristics, such as a short lifespan, early maturation, high mortality, and microhabitat specialization. In this study, we investigated breeding season and population fluctuation patterns of a gobiid CRF fish Lubricogobius exiguus. At our field study site, the breeding season of L. exiguus extended from April to November. The population densities of L. exiguus fluctuated considerably, starting at low density early in the breeding season, increasing to a peak in the middle of the season, and stabilizing at a medium density by the end of the season. This seasonal pattern was influenced by two peaks in juvenile recruitment, and the adult population increased after these peaks. The fluctuating numbers of juveniles and adults suggest that some individuals may have a short post-settlement lifespan of less than 80 days.

Don’t count your eggs before they hatch: differential survival of artificial bird nests in an anthropogenically modified landscape in western Mexico

Don’t count your eggs before they hatch: differential survival of artificial bird nests in an anthropogenically modified landscape in western Mexico

Predator-specific mortality of sage-grouse nests based on predator DNA on eggshells.

Greater sage-grouse (hereafter sage-grouse; Centrocercus urophasianus) populations have declined across their range. Increased nest predation as a result of anthropogenic land use is one mechanism proposed to explain these declines. However, sage-grouse contend with a diverse suite of nest predators that vary in functional traits (e.g., search tactics or hunting mode) and abundance. Consequently, generalizing about factors influencing nest fate is challenging. Identifying the explicit predator species responsible for nest predation events is, therefore, critical to understanding causal mechanisms linking land use to patterns of sage-grouse nest success. Cattle grazing is often assumed to adversely affect sage-grouse recruitment by reducing grass height (and hence cover), thereby facilitating nest detection by predators. However, recent evidence found little support for the hypothesized effect of grazing on nest fate at the pasture scale. Rather, nest success appears to be similar on pastures grazed at varying intensities. One possible explanation for the lack of observed effect involves a localized response by one or more nest predators. The presence of cattle may cause a temporary reduction in predator density and/or use within a pasture (the cattle avoidance hypothesis). The cattle avoidance hypothesis predicts a decreased probability of at least one sage-grouse nest predator predating sage-grouse nests in pastures with livestock relative to pastures without livestock present during the nesting season. To test the cattle avoidance hypothesis, we collected predator DNA from eggshells from predated nests and used genetic methods to identify the sage-grouse nest predator(s) responsible for the predation event. We evaluated the influence of habitat and grazing on predator-specific nest predation. We evaluated the efficacy of our genetic method by deploying artificial nests with trail cameras and compared the results of our genetic method to the species captured via trail camera. Our molecular methods identified at least one nest predator captured predating artificial nests via trail camera for 33 of 35 (94%) artificial nests. We detected nest predators via our molecular analysis at 76 of 114 (67%) predated sage-grouse nests. The primary predators detected at sage-grouse nests were coyotes (Canis latrans) and corvids (Corvidea). Grazing did not influence the probability of nest predation by either coyotes or corvids. Sagebrush canopy cover was negatively associated with the probability a coyote predated a nest, distance to water was positively associated with the probability a corvid predated a nest, and average minimum temperature was negatively associated with the probability that either a coyote or a corvid predated a nest. Our study provides a framework for implementing an effective, non-invasive method for identifying sage-grouse nest predators that can be used to better understand how management actions at local and regional scales may impact an important component of sage-grouse recruitment.

Decades of artificial nests towards African penguin conservation—Have they made a difference?

Abstract African penguins are among the most threatened seabird species globally and an African Penguin Biodiversity Management Plan (BMP) published in 2013 guides conservation strategies to prevent their extinction. To counter the impact of past guano exploitation which reduced the nesting habitat of these burrowing seabirds, rendering them vulnerable to predators and extreme weather events, a suite of artificial nests was deployed in various colonies over the past decades with varying success. The BMP called for new nest designs to maximise breeding output. This study assesses African penguin breeding success over the past 14 years in four types of artificial nests and in natural nests at all major colonies in South Africa. Overall, artificial nests outperformed natural nests and successfully increased breeding output of African penguins by 16.5% (95% CI: 6.7–26.2). No design was, however, consistently most effective across locations. For example, fibreglass nests had the poorest hatching success of all nest types at one colony (Bird Island), but outperformed cement nests at another (Boulders Beach). The latest design of double‐layered ceramic nests tended to perform better than other artificial nests, although not consistently at all colonies and occupancy rates were low in some areas. Practical implication. The deployment of artificial nests proved to be a successful conservation measure for African penguins although the variety of habitats in the different colonies seems to have prevented a one solution‐fits‐all approach. The consistent poor breeding output in some areas in all nest types (<30% at the mainland colony in Simons' Town and the islands in Algoa Bay) further calls for colony‐specific conservation strategies beyond artificial nests, while the continuous decline in African penguin numbers globally calls for broader measures urgently, primarily increasing access to their forage fish prey.

Assessing population viability and management strategies for species recovery of the critically endangered Puerto Rican parrot

AbstractRecovery of endangered species is challenging and lengthy, especially when it involves reintroduction and dynamic environmental conditions. Because managers often need to decide between many management strategies with uncertain outcomes, periodically assessing progress toward recovery using population viability analysis (PVA) can help guide decision‐making. We developed a PVA for the critically endangered Puerto Rican parrot (Amazona vittata) to evaluate current status and potential future management strategies to reach goals set in the Recovery Plan. Having grown from their nadir of 13 birds in 1976 to 686 in 2021, the recovery effort has made great progress. Using 15 years of data, we built an individual‐based PVA that included interactions between two captive and three wild populations connected via annual releases. If management continues as planned, the wild populations have no to moderate risks of extinction (0–32%) over the next 100 years. However, wild populations remain dependent on releases to sustain growth, and recovery targets for stable population growth and connectivity have not yet been reached. Our analysis suggests that hurricanes are an impediment to reaching recovery targets and impact some wild populations more than others based on geography. Projections with climate‐change‐induced higher hurricane impact resulted in wild populations being less likely to stabilize. We identified demographic rates and associated management strategies that could positively impact wild populations: increasing reproduction (e.g., via increasing artificial nests, improving nest success) and decreasing first‐year mortality (e.g., via targeted predator control). Based on our current understanding of Puerto Rican parrot demographics, species recovery will continue to be management‐dependent unless demographic rates can be altered. As more data are gathered, especially for data‐sparse populations and in the face of environmental change, future iterations of this model can re‐evaluate progress, update management strategies, and provide support for deciding if and when to delist this iconic species.

Landscape structure and site characteristics influence whether the northern house martin Delichon urbicum occupies artificial nests.

Artificial nest sites can support populations of endangered species when they are correctly installed. Here we analysed the characteristics and conditions that determined whether the northern house martin Delichon urbicum occupied more than 300 artificial nests around the city of Münster, Germany. We found that artificial nest occupation rates were influenced by various environmental and temporal factors. Positive influences included a longer time since installation and, to a lesser extent, the number of artificial nests at the same site. Negative impacts were observed from higher proportions of sealed surface cover in the surrounding area and, to a lesser extent, southward exposure. The distance to the nearest water body and the number of occupied natural nests showed no significant effect. We compared our results with descriptive evidence from the grey literature and published reports, and we give recommendations for installing artificial house martin nests for conservation practitioners. Future studies should also investigate the potential negative effects of 'dirt boards' below the nests and of gaps between the roof and the artificial nests.

Slit in a Nest Site Influences the Nest Site Selection in Cavity Nesting Ant Colonies.

For ants, nests provide a refuge against predators and protection from environmental factors. Thus, choosing a good nest site is important for an ant colony, but nest sites are limited resources. Ants of the genus Temnothorax inhabit small cavities in, e.g., acorns, twigs and under rocks. Earlier, it was shown that the ants are able to choose a superior site. In this study, using binary choice tests, we studied the nest site selection by Temnothorax crassispinus ant colonies that typically inhabit empty acorns. For this purpose, we used artificial nest sites without and with an additional slit in the nest wall, mimicking the cracks in potential nest sites under natural conditions. We found that the ant colonies preferred artificial nest sites without these slits. However, no difference in the number of colonies inhabited nest sites with a slit vs. those without a slit was found when the slits were closed using transparent food foil, which prevented the air flow while keeping an inflow of light. What is more, additional light through the hole in the red filter covering the artificial nest sites had no influence on the nest site selection. The results of this study suggest that the air flow through a slit in the nest site wall, rather than additional light, influences the nest site selection. The absence of cracks, e.g., in acorns, could be an indication of the durability of potential nest sites. Thus, choosing a cavity without such damage could be beneficial for the ant colonies.

Satellite-derived measures of habitat structure perform as well as locally recorded measures in predicting predation on artificial nests in central European agricultural landscapes

Ground nesting birds have declined throughout Europe, with the reduction of habitat structure in agricultural areas being a key contributing factor. Habitat structure is vital not only for providing food and suitable microclimates for these species but also limits nest predation. Field assessments of habitat structure have, historically, been the most common way of identifying areas of low nest predation. However, they are limited in their applicability over wide areas due to time, money, and logistics. Remotely sensed measures (e.g., recorded by a satellite) can address these issues. Normalised difference vegetation index (NDVI) is a measure of the ‘greenness’ of an area and correlates with habitat structure. We conducted an artificial nest experiment over three years (2019, 2020, 2023) in Baden, Austria to test the relationship of NDVI to nest predation in an agricultural landscape. Critically, we compared whether NDVI could predict nest predation as well as locally recorded variables (ground cover, vegetation height, etc, ). We report that NDVI performs equally well at predicting nest predation, with predation decreasing with higher values of NDVI, signifying greater habitat structure. This was supported by our finding that predation probability decreased with greater ground cover (a locally recorded variable). Additionally, we found that areas with greater partridge numbers had higher predation and circumstantial evidence that birds are the primary predator in our study area. Overall, our study shows that satellite-derived measures of habitat structure have untapped potential in identifying areas of high nest predation for European ground nesting birds in agricultural landscapes.

Disentangling ground-nest predation rates through an artificial nests experiment in an area with western capercaillie (Tetrao urogallus) presence: martens are the key

The western capercaillie (Tetrao urogallus) is a species of conservation concern that has been experiencing a severe decline in many regions of Europe. The poor breeding success rather than mortality of full-grown birds has been suggested to be responsible for its decline, been the nest loss a potential driver of the low productivity (number of chicks per female and year) of capercaillie. Working in a capercaillie population in the Pyrenees, we aimed to provide further insights into nest predation by monitoring 82 artificial nests (58 of them with camera traps), and estimating the population density of predators using camera traps and applying random encounter model and camera trap distance sampling. Pine/stone martens -Martes foina, Martes martes- were the species with higher nest predation rates (23%) despite being the less abundant (0.49 ind/km2), followed by foxes -Vulpes vulpes- (11%) and a population density of 3.37 ind/km2, and wild boar -Sus scrofa- (4%) and 6.95 ind·km− 2; predators could not be identified at 27% of the events. After fitting statistical models on the nest predation data, we observed that the martens’ encounter rate (i.e. number of martens detected per camera and day) and the altitude had a positive significant effect on the artificial nest predation probability. While caution is recommended in artificial nest experiments, our results are valuable highlighting the importance of martens and red foxes when addressing nest predation to promote the breeding success and population recovery of western capercaillie populations.

Evaluating deterrents to reduce depredation of wood duck eggs in nest boxes

AbstractWood ducks (Aix sponsa) are secondary natural cavity‐nesting species that also nest in artificial nest boxes. Since the early 20th century, nest boxes have been widely deployed in North America to increase nesting sites for wood ducks and bolster production. Equipping nest boxes with a predator guard beneath the box is a common practice to deter climbing predators from accessing boxes; however, there is no device to repel avian predators. We found that eastern rat snakes (Pantherophis alleghaniensis) and woodpeckers (Picidae) were primary predators of wood duck eggs in boxes in North Carolina and South Carolina. Accordingly, we designed experiments to deter snakes and woodpeckers using a commercial brand of snake repellent pellets and a plastic raptor decoy, respectively. Male and female snakes that accessed boxes averaged 1.4 m (SE = 2.0 cm) in length. Digital camera data indicated that snakes climbed nest box posts and thrust their anterior body atop predator guards to continue their ascent into the box. We recorded 671 nest failures of which rat snakes accounted for 39.9% (n = 268) and woodpeckers 22.4% (n = 150). Snakes consumed ≥649 eggs, observed as protuberances in their stomachs. Our experiment showed that commercial snake repellent pellets did not deter snakes (P = 0.957). Placing a plastic hawk decoy atop nest boxes when females were incubating ≥12 days increased nest survival during the incubation stage (P = 0.001). Wood duck nest boxes at our study sites may be experiencing increased nest predation by rat snakes due to poor maintenance and installation of predator guards. Rat snakes and woodpeckers may be depredating wood duck eggs in the southeastern United States at unknown rates, potentially decreasing production and recruitment from these structures.

Groupings of arthropods in nest boxes inhabited by Phoenicurus phoenicurus in pine forests of Northeastern Ukraine

The common redstart Phoenicurus phoenicurus (Passeriformes, Muscicapidae) is one the most appealing insect-eating birds living in parks, gardens, and other cultured landscapes of Europe, Central and Western Asia, and Northern Africa. We analyzed the nests of Ph. phoenicurus after the chicks had flown away. Throughout the reproductive period, in the pine forests of Northeastern Ukraine, those nests contained 23 species of arthropods, belonging to 15 families, 9 orders. The analysis of the distribution of arthropods by ecological groups revealed a correlation between the number of arthropods and parameters of breeding success and air temperature in the national nature parks. To attract Ph. phoenicurus to the pine forests of the region, we used standard-sized artificial nests made of wooden sections. The results of the study demonstrated a high level of biodiversity of nidicolous arthropods in the nests of Ph. phoenicurus in the pine forests in 2019–2023. The largest share of nidicolous invertebrates among the ecological groups was comprised of “nourishment for chicks”. A large portion of arthropods in the nest of Ph. phoenicurus was polyphages. The results provide a better understandanding of the dynamics of invertebrates’ populations in artificial nests occupied by Ph. phoenicurus, their effect on the breeding successfulness of this species, and also other significant factors. This is important for designing effective strategies of preserving the populations of this species in the region of research. Further research is needed to specify the factors influencing the distribution of the bird and species composition of arthropods in its nests in other types of ecosystems within the bird’s range.

Proximity of shrub nests to ground nests increases the chance of ground nest predation

In nature, ground-nesting birds rarely nest under an active shrub nest of another species. In the case of the proximity of the two nest types, we assumed that if a nest predator finds one nest, it will most likely rob the other nest as well. To test this, we exposed artificial nests with one quail and one plasticine egg on shrubs and underneath on the ground, in oleaster shrub rows and forest edges. We found a higher predation on ground nests than on shrub nests in both habitats. More importantly, predation events in shrub nests resulted in a higher predation of more concealed ground nests too. Our results suggest that proximity of two nest types can be detrimental to predation pressure, especially in forest edges.

Distribution of brood of the acorn ant Temnothorax crassispinus in artificial nests after forced migration

Nest sites are important for social insects, as they provide refuge against enemies and ensure optimal conditions for the brood development. In large nests, the different chambers can be used for different reasons; for example, for food storage or as a brood chamber. Acorn ants from the genus Temnothorax dwell in small cavities in acorns and wood; however, even such small chambers can have a high degree of spatial heterogeneity. During this study, the distribution of brood items of the acorn ant Temnothorax crassispinus inside artificial nest cavities composed of three chambers in a linear system was analysed. 29 ant colonies were photographed 13 times during a period of approximately one month: during three consecutive days, and after forced migrations. I found that the distribution of the brood inside the nest cavity was similar during the consecutive days; however, after the forced migration, the distribution typically changed. Almost all the brood items were kept farther from the entrance. Keeping the brood farther from the entrance could be explained as a safer option.

Does Nesting Material Affect Wood Duck (Aix sponsa) Nest Box Selection, Reproduction, and Eggshell Bacteria?

Wood Ducks (Aix sponsa) are secondary cavity nesters that use natural cavities and artificial nest boxes, the latter of which has been attributed to the recovery of populations across the southeastern US. Continual use of these boxes results in a buildup of bacteria, parasites, and other pathogens. To avoid the accumulation of these deleterious organisms, best management practices include the occasional removal of old nesting material (i.e., wood shavings) and replacement with fresh wood shavings. No studies have been performed on the effects of shaving material on nest box selection, nest success, and bacterial growth. We monitored 142 and 111 nest boxes in Florida and Georgia, USA, respectively, and filled a random sample with aspen or cedar shavings. We then swabbed the surface of 144 and 150 eggs during 2020 and 2021, respectively, to screen for culturable bacteria. We detected no effect of shaving type on nest box selection, nest success, or egg surface bacterial growth. We found 3-8 bacterial colony types (1-123 colony-forming units [CFU]/box) and 1-8 bacterial colony types (3-382 CFU/box) among the Georgia and Florida samples, respectively. We detected no effect from shaving type on Wood Duck reproduction or bacterial growth in the sampled nest boxes. We concluded that both shaving types are suitable nesting materials for box-nesting Wood Duck populations and the continued use of either would be a reasonable decision for managers.

Osmia3DNest—Novel designed 3D printed artificial nest for solitary cavity‐nesting bees

Abstract The availability and appropriateness of nesting sites significantly influence the reproductive success and overall welfare of wild bees. Human‐induced factors contribute to the destruction of natural nesting habitats. To address these limitations, innovative solutions such as the development of artificial nests, offer alternative nest sites to support wild bee populations. We designed the Osmia3DNest, a 3D printed standardized nest tube for solitary cavity‐nesting bees, aiming to provide a safe for the environment, long‐life, time‐saving and biodegradable product that anyone can print. We proudly present the two Osmia3DNest models for mason bees—closed and open—using polylactic acid filament. We demonstrate the effectiveness of Osmia3DNest on mason bee reproduction parameters compared with traditional reed nests. Osmia3DNest can be an alternative to the other artificial nests, which people can customize for their necessity depending on their place of living (rural or urban area), and they can also be washed and reused several times and then decomposed. Osmia3DNest holds potential for wildlife biologists, management of pollinators, and educational outreach, offering adaptability for different bee species and experimental needs.

Etnobotani Tikung Masyarakat Melayu Dusun Batu Rawan Kabupaten Kapuas Hulu dalam Budidaya Madu Secara Tradisional

Wild Honey is produced directly from the hives of Apis dorsata bees or wild bees that live in forest areas. Wild Honey is produced through traditional methods that utilize plants and are not livestock. Plants that are utilized in the form of plant wood as artificial nests called tikung and flowers from bee food trees. The purpose of this study was to determine the types of plants as tikung wood and bee food trees and document the knowledge of traditional honey farmers about the ethnoecology of Batu Rawan Hamlet, Kapuas Hulu Regency. This study used purposive sampling method in determining respondents and 15 respondents were obtained, then continued with semi-structured interviews. Data analysis was conducted with citation frequency. The results showed that there were 5 species of tikung wood and 15 species of bee food trees belonging to 12 families. Fagraea fragrans, Shorea belangaran, Litsea resinosa, Gluta renghas, Shorea sp., are plant species used as tikung wood trees, the dominant species reported by respondents is Litsea resinosa which is 93.3%. Mesua hexapetala, Syzygium claviflorum, Barringtonia acutangula, Ternstroemia sp., Carallia brachiata, Teysmanniodendron sarawakanum, Syzygium sp., Gomphia serrata, Eugenia sp., Syzygium inophyllum, Timonius flavescens, Ixora mentangis, Syzygium attenuatum, Memecylon edule, Crudia teysmannii are plant species used as bee fodder trees, bee fodder tree species reported dominantly by respondents are Barringtonia acutangula species which is 100%.

Factors influencing the occurrence of the House Sparrow Passer domesticus (Linnaeus, 1758) (Aves: Passeriformes: Passeridae) in Bhavnagar, Gujarat, India

The present study aims to understand key factors influencing the House Sparrow population across different habitat scales in Bhavnagar, Gujarat, India. Correspondingly, different variables such as changes in habitat composition, sound levels, and density of mobile phone base stations were considered with reference to the occurrence of the House Sparrows across the study area. During the study period (December 2016 to November 2018), the number of House Sparrows was recorded through point count without distance estimate method. Non-parametric tests were employed to assess variations in different variables and their correlation with the presence of House Sparrows, revealing that changes in local habitat composition significantly influence their occurrence. Shrubby vegetation, cowsheds, and old/traditional structures emerged as crucial predictors positively impacting House Sparrow’s presence, particularly in urban areas where suitable habitat patches are scarce due to urbanization and modern lifestyles. The decline in these habitats has significantly impacted House Sparrow populations. To counter this decline, implementing strategies like providing artificial nest sites is being considered. However, it’s crucial to ensure that there are adequate shelter and food resources available to effectively conserve the species.

Evaluating diversionary feeding as a method to resolve conservation conflicts in a recovering ecosystem

Abstract The recovery of mammalian predators of conservation concern in Europe is a success story, but their impact on some prey species of conservation concern may cause conservation dilemmas. This calls for effective intervention strategies that mitigate predator impacts without compromising their recovery. We evaluated diversionary feeding as a management intervention tool to reduce depredation on nests of rapidly declining Western capercaillies in Scotland. We studied the influence of diversionary feeding provision on the fates of artificial nests deployed using a replicated and representative randomised landscape‐scale experiment. This comprised 30 'paired' control (no diversionary feeding) and treatment (diversionary feeding applied) sites, 60 in total, each containing six artificial nests distributed across 600 km2. The experiment was replicated over 2 years, and in the second year, the control‐treatment pairs were reversed, yielding 60 treatment and 60 control sites and 720 artificial nests. Diversionary feeding substantially reduced depredation of artificial nests, translating into an 82.5% increase in predicted nest survival over 28 days of incubation. The increase in survival was mostly accounted for by a reduction in the probability that a pine marten, the main nest predator, consumed or cached eggs. Diversionary food also significantly reduced nest predation by badgers, although the magnitude of this effect varied by year. Synthesis and applications. Diversionary feeding is an easily employable method shown in this study to reduce predator impact (functional) without lethal (numerical) intervention. Managers should proceed with its application for conserving capercaillie in Scotland without delay.

Analysis of Artificial Nest Inhabitancy and Factors Affecting Their Inhabitation of Different Avian Species in Uvas C-Block Pattoki Pakistan

Artificial nesting is considered as a common experimental practice throughout the world. Artificial nest boxes offer a convenient way for carrying out experiments, identifying birds and capturing birds for research and conservation. Studies on the effects of urbanization on birds has revealed that species richness is negatively impacted by urbanization and fragmentation which decreases bird diversity while increasing bird density. This study was designated to determine the inhabitancy of birds inside artificial nests as well as enlists the factors which affect the inhabitation of birds in such nests. The experiment was conducted at the University of Veterinary and Animal Sciences, C-Block, Ravi Campus, Pattoki. Google Earth Pro (a software) was used to take the satellite image of experimental site. Further, geo-referencing and digitization of image were done by using ArcGIS version 10.1. This digitized image was categorized into four classes as roads, barren, buildings, ponds and agricultural land for quantification of land use of experimental site. Ten types of artificial nests varied by nests shapes, size and material were installed at five selected sites named as building site, barren site, pond site, road site and agriculture land site. Total sixty (n=60) artificial nests were installed at five nest sites, hence each site possessed twelve nests supported with iron wire and nails. All of these nests were installed approximately among 4 and 5m above ground. A measuring tape (40 feet) was used to measure the height of each tree by the yardstick measuring method. The area obtained after the digitization of the boundary of (UVAS) C-Block was 46.03 hectares. The findings indicated that throughout the trial's last three months (January, February, and March), twelve nests out of sixty were occupied at the ponds site, H.S-1, and botanical garden whereas others were remained unoccupied. The overall rate of occupancy was 20%. Further, eight nests were those where in birds’ activities were observed. It is concluded that inhabitancy of birds inside artificial nests is influenced by both natural and anthropogenic factors including the presence of water, food sources, human activities nesting sites and predators. This study will contribute to provide information that helpful that will be helpful for the future conservation of birds and wildlife management.

Attractant spray enhances nesting preference and reduces macroparasite infestation of Osmia cornuta

AbstractMason bees (Osmia. spp) can provide an alternative for crop pollination management in addition to the Western honeybees (Apis mellifera). Targeted evidence‐based guidelines can improve cost‐effective management of mason bees. Here, I test the effect of an attractant spray developed in the United States for improving the nesting preference for artificial trap nests of mason bees in Belgium. More specifically, this study investigates the effect of the attractant spray on the nesting preference and nesting performance of the European orchard bee (Osmia cornuta), as well as its effect on the infestation of nest‐associated macroparasites. The number of sealed nesting cavities was twice as high in the trap nests that were treated with the attractant spray. Nesting performance expressed as number of brood cells per cavity, successful cocoon formation, adult emergence, proportion of female bees in the offspring and the number of dead larvae was not different between the treated and the untreated nests. Overall infestation of macroparasites, and infestation of drosophilid flies in particular, were both twice as high in untreated nests. This study provides evidence that the attractant spray improves nesting preference and reduces macroparasite infestation in O. cornuta. The use of this attractant can provide growers and stakeholders with an effective management strategy to prevent infestation by macroparasites and promote efficient bee breeding.