Beetle Activity Research Articles

Dung inhabiting insects, their diversity, abundance and bio ecology of coprine beetles

The insects most prominently colonized in a nutrient-rich fresh dung habitat are mainly beetles and flies and the group is termed collectively, the dung community. Coprophagous insects play an important role in tropical ecosystems by providing essential functions including mechanically breaking down excrement into smaller-sized particles, mixing of organic matter in the soil, soil aeration, nutrient cycling and to remove unhealthy materials from their surroundings. Against this backdrop, present study is an attempt to assess the insect diversity and abundance inhabiting dairy farm dung community in North & South 24 Parganas, West Bengal along with the study on the life cycle pattern of frequently encountered dung beetle taxa, Oniticellus cinctus (Fabricius) and to observe their role in the decomposition. Altogether 2 dung beetles, 4 dung loving beetles, 8 dung loving flies, 17 dung associated insects of different groups, one mesostigmatic mite species are recorded from cow and buffalo dung community during the study period. December is the period of maximum dung beetle abundance. Beetle activity gets greatly diminished with the rise of temperature above 30 °C. The brood ball made by the functional group ‘Dwellers’ is for oviposition. The brood balls provide the immatures with an assured food supply. Egg to adult developmental period ranges between 43-51 days. The teneral adult period observed under laboratory conditions is 2-3 days. Our findings show that extensive management practices result in more pats with higher insect abundances. Data proves that the members of these two orders, Coleoptera and Diptera are almost perfectly separated seasonally. Flies are most abundant in the premonsoon while beetles during monsoon and postmonsoon. Season is therefore the main temporal axis separating ecologically similar species of dung-inhabiting insects in tropical habitats, while succession aggregates species that may have similar environmental tolerances. This separation between ecologically similar taxa of beetles and flies may be attributable to either competition-based niche segregation or to temperature tolerance-based habitat filtering.

Survey on the seasonal incidence of insect pests of soybean in Bemetara district of Chhattisgarh state

Survey work for visualization of real pest problem of four blocks i.e. Bemetara, Berla, Saja and Nawagarh of Bemetara district (C.G.) was conducted during Kharif, 2017-18 and 2018-19. Ten villages in each block were visited during crop growth period. Girdle beetle, S. litura, C. acuta, B. tabaci and E. kerri were observed as major insect pests in soybean ecosystem under the blocks of Bemetara district. The maximum block seasonal mean activity of girdle beetle was recorded in Berla block with 5.3 damaged plants/mrl in which the Damai village of Berla block having maximum intensity of girdle beetle with 9.5 damaged plants/mrl. Bemetara block was earmarked for maximum block seasonal mean population of leaf defoliators i.e. S. litura and C. acuta with 3.2 larvae/mrl and 3.7 larvae/mrl, respectively. However, Mohbatta village of Bemetara block received maximum population of S. litura (7.6 larvae/mrl) and C.acuta (6.2 larvae/mrl). In Nawagarh block, highest block seasonal mean intensity of B. tabaci was recorded with 19.0 whiteflies/five plants. Another sucking pest E. kerri showed maximum block seasonal mean population in Bemetara block (6.9 jassids/five plants). Among the different blocks, Bemetara and Berla blocks were found favourable for maximum activities of predatory insects.

Promotion of ground beetles by integrating perennial energy crops into existing agricultural landscapes

Perennial energy crops as an alternative to maize (Zea mays L.) have the potential to promote biodiversity and associated ecosystem services in agricultural landscapes. Ground beetle (Carabidae) assemblages of cup plant (Silphium perfoliatum L.), Virginia mallow (Sida hermaphrodita L.) and tall wheatgrass (Thinopyrum ponticum Podp.) were assessed in four replicated field trials in Bavaria and compared to an annual crop rotation (winter rye (Secale cereale L.)), maize, winter wheat (Triticum aestivum L.)). Additionally ground beetle fauna in cup plant was compared to that in maize on fields under real farm conditions at six sites in Bavaria with widely diverging soil–climate conditions. Ground beetles were collected in pitfall traps in winter (one field trial), spring (four field trials) and summer (six fields) in 2017.Overall, results for activity density and species richness of ground beetles under perennials compared to annuals were site-specific and there were no pronounced differences of species compositions.The highest activity density of seed-eating ground beetles occurred in Virginia mallow, which was invaded by weeds. Some indication of benefits for hibernation and larval development in cup plant were found. Tall wheat-grass had the lowest ground beetle diversity and activity density of all crops. Species accumulation curves on farmed fields in summer indicated higher species richness of ground beetle fauna in cup plant than in maize. Diversification of cultivated plants with perennial energy crops can provide additional niches for ground beetles, such as undisturbed soil. Effects, however, varied with site and species/genus in a complex manner.

Spatial orientations of common bean (Phaseolus vulgaris L.) influence the activity and population dynamics of bean stem maggot (Ophiomyia phaseoli) and bean foliage beetle (Ootheca mutabilis)

Common bean (Phaseolus vulgaris L.) is an important legume for food and income for smallholder farmers all over the world. Pests such as bean stem maggot BSM (Ophiomyia phaseoli) and bean foliage beetle BFB (Ootheca mutabilis) pose a serious challenge to production. Many practices have been employed to manage these pests. However, little or no emphasis has been on basic agronomic practices such as plant spacing as a tool for pest management. In the present study, the role of plant orientation (plant spacing) on the activities and population dynamics of BSM and BFB was examined in a pesticide-free field trial in Bamenda, Cameroon from March to July, 2020. Different plant orientations namely 15cm x 15cm (~442500 plants/ha), 20cm x 20cm (~250000 plants/ha), 30cm x 30cm (~110000 plants/ha) and 40cm x 40cm (~62500 plants/ha) were test in a randomized complete block design with 4 replicates. Data was collected on oviposition holes on leaves of common bean by BSM, BSM population dynamics, leaf damage score by BFB, and population dynamics of BFB. The number of oviposition holes, the mean cumulative number of BSM, the mean leaf damage scores and the mean cumulative number of BFB were significantly higher (P < .05) in dense plots (15cm x 15cm) than in the other plots. The activity of BSM and BFM increased over time. The Principal Component Analysis revealed that the first two components accounted for 99.17% of the variation. Linear discriminant analysis with Mahalanobus distances with an 87.5% cross-validation by Jacknife procedure revealed that spatial orientation of 20cm x 20cm and 30cm x 30cm were very similar and significantly (F = 99.27, df = 3, 12, P < .001) different from the others. For pest management purposes, plant orientations of 20cm x 20cm and 30cm x 30cm can be recommended since they recorded low BSM and BFB activity. For future perspective, it is important assess the effect of different plant orientation on yield and pest parameters concurrently.

Communities of ground beetles (Carabidae, Coleoptera) in broad-leaved forests of protected and urban areas of the Kaluga Oblast (European Russia).

BackgroundThis sampling-event dataset provides primary data about species diversity, population and seasonal activity of ground beetles (Carabidae, Coleoptera). The study was carried out in broad-leaved forests of protected ("Kaluzhskiye Zaseki" Nature Reserve and Ugra National Park) and urban areas (the Kaluga City) of the Kaluga Oblast. Carabids were collected from April to October during 1995-1998 by pitfall traps. In total, 108,000 adult individuals of the Carabidae family were sampled; 105 species from 38 genera were counted.New informationThis dataset is the first sampling-event dataset about the Carabidae family for the European part of Russia. It provides biodiversity data for new territory (Kaluga Oblast) and contributes to filling gaps in the global biodiversity distribution of the Carabidae family. Part of the data was collected from unique old-growth broad-leaved forests.

Impact of dung beetle activity on the quality of water percolating through Allophanic soil

Dung beetles are described as key ecosystem service providers. Because of ecosystem benefits from their activity, approval has been granted to import dung-burying beetles for release into pasture systems in New Zealand. Concerns remain, however, about the impact of dung beetle tunnelling and burying activity on the leaching of contaminants through soil. To assess the quality of water leaching from soil cores containing dung beetles, a trial was conducted using 12 intact Allophanic soil core lysimeters under in situ soil moisture and temperature regimes. Four lysimeters received dung and beetles (Geotrupes spiniger and Onthophagus taurus), four received dung and no beetles and four (controls) received no dung and no beetles. The quality of water was assessed by monitoring leachate samples for Escherichia coli and total N and P for 6 months. Key findings of the study were that concentrations of E. coli, N and P leaching through the lysimeters treated with dung beetles were not significantly different from soils without dung beetles. In addition, where dung was buried there was a significant decrease in E. coli and total N and P in surface soil compared with the lysimeters receiving dung only. Results from this study suggest dung beetle tunnelling and burying activity does not negatively impact the quality of water leaching through Allophanic soil.

Spread of Dutch elm disease in an urban forest

A complex network model for the spread of Dutch Elm Disease in an urban forest is formulated. American elms are the focus of the model. Each elm can be in one of five states, a combination of their life and epidemiological status. Each tree is also potentially a host to a population of elm bark beetles, the vectors of Dutch Elm Disease. The epidemiological dynamics of trees is governed by a stochastic process that takes into account the dispersal of spore-carrying beetles between trees and potential contacts between tree root systems. The model describes seasonal variations of beetle activity and population dynamics. Numerical simulations and sensitivity analyses of the model are carried out. In this introductory paper, we use data from the City of Winnipeg, where Dutch Elm Disease is prevalent, and focus on two neighbourhoods representative of a residential area and an area with urban parks.

Life cycle of ground beetle Chlaenius tristis reticulatus Motschulsky, 1844 (Coleoptera: Carabidae) in the condition of Western Transbaikalia

In the conditions of Western Transbaikalia, Chlaenius tristis reticulatus Motschulsky, 1844 has a one-year late spring – early summer life cycle with the hibernation of a young generation of beetles. The interpretation of their life cycle is based on the study of sex and age-related structure of imago, the seasonal activity of generative females, the above-ground activity of larvae, and stages of the development of beetles in the laboratory conditions. The changes in the seasonal activity of beetles on meadows with different soil moisture (steppificated, moistened, and marshy meadows) were identified.

Flight activity of rove beetles (Coleoptera: Staphylinidae) in the agricultural landscape in the Leningrad Region

Flight activity of rove beetles (Coleoptera: Staphylinidae) in the agricultural landscape in the Leningrad Region

Do bark beetle outbreaks amplify or dampen future bark beetle disturbances in Central Europe?

Bark beetle outbreaks have intensified in many forests around the globe in recent years. Yet, the legacy of these disturbances for future forest development remains unclear. Bark beetle disturbances are expected to increase further because of climate change. Consequently, feedbacks within the disturbance regime are of growing interest, for example, whether bark beetle outbreaks are amplifying future bark beetle activity (through the initiation of an even‐aged cohort of trees) or dampening it (through increased structural and compositional diversity).We studied bark beetle–vegetation–climate interactions in the Bavarian Forest National Park (Germany), an area characterised by unprecedented bark beetle activity in the recent past. We simulated the effect of future bark beetle outbreaks on forest structure and composition and analysed how disturbance‐mediated forest dynamics influence future bark beetle activity under different scenarios of climate change. We used process‐based simulation modelling in combination with machine learning to disentangle the long‐term interactions between vegetation, climate and bark beetles at the landscape scale.Disturbances by the European spruce bark beetle were strongly amplified by climate change, increasing between 59% and 221% compared to reference climate. Bark beetle outbreaks reduced the dominance of Norway spruce (Picea abies (L.) Karst.) on the landscape, increasing compositional diversity. Disturbances decreased structural diversity within stands (α diversity) and increased structural diversity between stands (β diversity). Overall, disturbance‐mediated changes in forest structure and composition dampened future disturbance activity (a reduction of up to −67%), but were not able to fully compensate for the amplifying effect of climate change. Synthesis. Our findings indicate that the recent disturbance episode at the Bavarian Forest National Park was caused by a convergence of highly susceptible forest structures with climatic conditions favourable for bark beetle outbreaks. While future climate is increasingly conducive to massive outbreaks, the emerging landscape structure is less and less likely to support them. This study improves our understanding of the long‐term legacies of ongoing bark beetle disturbances in Central Europe. It indicates that increased diversity provides an important dampening feedback, and suggests that preventing disturbances or homogenizing post‐disturbance forests could elevate the future susceptibility to large‐scale bark beetle outbreaks.

Understory vegetation response to mountain pine beetle disturbance in northern Colorado lodgepole pine forests

Understory plants are an important element of forests, having a considerable influence on ecosystem functioning and canopy-tree development following disturbance. Recent bark beetle outbreaks across western North American forests have caused extensive canopy mortality, creating new growing conditions that provide the opportunity for changes within the intact understory. Over a five-year period following peak mountain pine beetle (MPB) activity across lodgepole pine-dominated forests in Rocky Mountain National Park, Colorado, we measured the changes in plant diversity, cover, and dominance by lifeform and quantified tree regeneration rates. Average species richness and diversity increased, but overall plant cover did not change. Graminoids appeared to benefit the most, increasing in average cover, richness, and relative dominance. The rise in graminoid dominance was largely at the expense of shrubs, which showed little ability to benefit from overstory mortality within the first years following attack. Most plant responses were positively related to the total tree basal area lost since the peak of the outbreak, suggesting that increased resource availability following tree death may benefit understory plants. However, a negative relationship between several understory variables and tree sapling density provides evidence that understory plants compete with saplings for the newly available resources. Tree seedling density nearly doubled over the duration of the study, indicating a strong regeneration pulse. Among species, lodgepole pine displayed the greatest tree seedling establishment. This is one of the first studies to use repeated measurements to describe this often-overlooked component of forest change associated with MPB disturbance.

Spatial and seasonal patterns of communal latrine use by spotted hyenas (Crocuta crocuta) reflect a seasonal resource defense strategy

Communal marking sites, or latrines, appear to play an important role in intraspecific communication and social dynamics in a wide range of mammal species. The spatial distribution of latrines can provide clues to their function and has been well documented in a number of species. Latrine use may vary considerably through time, however, and a more comprehensive approach to their study that considers spatial and seasonal patterns of use is required to understand more fully the costs and benefits of latrine use, and hence their adaptive significance. This study investigated spatial and seasonal patterns of latrine use by spotted hyena (Crocuta crocuta) in northern Botswana, examining their potential role in resource defense. Latrine characteristics and hyena activity were monitored to test the influence of season and location (relative to clan territories and roads) on latrine use. We conducted monthly scat counts (at 78 latrines) and continuously recorded hyena visitation (to 50 latrines) in five clan home ranges, demonstrating clear seasonal patterns in latrine use. Latrines were smaller in the wet season (November-March), resulting from fewer visits by hyenas, reduced scat accumulation, and the seasonal activity of coprophagous beetles. We speculate that such a seasonal pattern may be driven by reduced competition for food during the wet season. Latrines located within core clan areas were no larger or more frequently used than those in home-range boundary areas, but hyenas did preferentially place latrines alongside roads and were more likely to reuse road-side latrines in subsequent years. This pattern was not due to observer detection bias and adds to the growing body of literature on the impact that roads and other anthropogenic features have on the communication and movement ecology of wild animals. Although most mammals use communal marking sites, very little is known about their function and detailed patterns of use in many species. We investigated latrine use in spotted hyena (Crocuta crocuta) and describe spatial and temporal marking patterns that are consistent with optimizing scent longevity and detection. Spatially, hyenas preferentially located latrines along the edge of man-made vehicle tracks, which may increase signal detection and transmission. Seasonal marking patterns suggest that hyenas optimize their communication by concentrating activity in the dry season, thereby avoiding the disruptive effects of coprophagous dung beetles and rain, and focusing activity during periods when food resources are expected to be scarcer. These results demonstrate seasonal and spatial optimization of communication, including in response to novel anthropogenic features in the environment such as roads, advancing our understanding of communication strategies in mammals more broadly.

Termites and necrophagous insects associated with early Pleistocene (Gelasian) Australopithecus sediba at Malapa, South Africa

This study focuses on two early Pleistocene Australopithecus sediba hominin specimens and associated fauna from Malapa, South Africa. These specimens have been interpreted as having fallen through a shaft opening into a cave, where they died and likely mummified, before being washed into a lower chamber. In order to better understand the taphonomy of the fossils and to identify the invertebrate agent(s) responsible for damage, we examined the fossils using high resolution imagery, and studied the site and associated breccia blocks in the laboratory for traces of invertebrate activity. We also conducted bone modification experiments with termites and hide beetles. Results show the presence of blowfly puparia within the cranium of the juvenile male (MH1), indicating that flies visited the facial orifices of the freshly decomposing corpse. Blowflies, which have a requirement to oviposit in daylight, imply that the body was exposed to sunlight for part of the day. A shaft opening that admitted sunlight is supported by the presence of a fossil fungus garden associated with MH2. Fungus gardens occur subsurface and sprout mushrooms in areas with dappled light. Analysis of the fossil surfaces revealed a pattern comprising 14 damage types that were made on relatively fresh bone. A bone modification experiment conducted with resident termites at the site showed that they created the same suite of microscopic surface features as those observed on the fossils. The features are mostly the result of harvesting symbiotic fungi from fresh bones and mineral-rich coatings from fossils. Damage resulting from the activity of hide beetles is similar to that of termites, apart from invasive edge gnawing produced by the beetles. This research highlights the importance of insect activity in the modification of fossils in the Cradle of Humankind World Heritage Site area and calls for consideration of this agent at other fossil sites in the region.

Peculiarities of the development and seasonal dynamics of the activity of epigean beetles of the Polyphaga suborder (Coleoptera) in fields of winter wheat in the conditions of Southern Ukraine

In total, 168 beetle species from 25 families of the suborder Polyphaga have been recorded on winter wheat crops. 116 species (about 20 families) are registered as stratobionts: 14 were dominants, 32 – subdominants and about 70 species were very rare. The main representatives of stratobios were Staphylinidae, Silphidae, Dermestidae, Histeridae, some Elateridae and Scarabaeidae and most Tenebrionidae. Most staphylinids are more numerous in spring (late April – first half of May) and sometimes in summer (especially dominant Tachyporus hypnorum). A high number of Silphidae was noted by mid-May, but decreased in the summer months. Two peaks of abundance are characteristic of Anthicidae, Latridiidae and Cryptophagidae: the smaller in spring (the first half of May) and the maximum in summer (the second half of June – early July). The number of Dermestidae increases gradually from mid-May and reaches maximum from late May to early or mid-June. Among Tenebrionidae, the species of genera Opatrum and Gonocepalum are more numerous in spring than in summer. Crypticus quisquilius were numerous by mid-summer. Among Elateridae, high number of Agriotes sputator was recorded from May to mid-June, and the appearance of Aelosomus rossi was recorded from mid-April, with a peak in the first half of summer. In spring, some Scarabaeidae (some species of Geotrupinae and Pentodon idiota), Histeridae and some species of weevils were more numerous in summer. In years with different meteorological conditions, significant discrepancies were noted in the timing of the rise and fall in the number of many beetles. But smaller differences in the number of specimens are noted between different years in comparision with individual phases of wheat vegetation. Some features of the sex index of beetles (higher during egg laying) and the development of dominant species are briefly considered.

Wood-borers in Historic Ships

ABSTRACT Using evidence of wood-borers in several of the National Museum of the Royal Navy’s historic ships, this article will examine the threat posed to the historic fabric by non-marine species and the reasons that we struggle to eradicate the problem. The relationship between fungal attack and beetle activity will be discussed, and the need for supporting research into this and other aspects of damage due to wood-boring species. HMS Victory, HMS Warrior and HMS Trincomalee all suffer from attack by wood-boring species, though the infestations are in different stages of development on each vessel. By investigating and employing an integrated pest management strategy on Trincomalee, we hope to learn more about the most effective means of combatting the much more widespread infestation of death watch beetle on Victory. Other wood-borers including weevil, furniture beetle and wharfborer are also present across our collection of ships, and all these species are facilitated by the damp conditions which can never be truly resolved as the ships are located in open coastal environments.

The optic lobe–pars intercerebralis axis is involved in circa’bi’dian rhythm of the large black chafer Holotrichia parallela

The large black chafer Holotrichia parallela exhibits ~ 48-h circa'bi'dian rhythm. Although circabidian rhythm is suggested to involve the circadian clock, no physiological studies have been conducted to verify this involvement. We examined the effects of optic lobe or pars intercerebralis removal on the circabidian rhythm. After removing both optic lobes, all beetles lost their circabidian rhythms (N = 25), but all beetles exhibited circabidian rhythm after removing unilateral optic lobe (N = 18). However, 22% of the latter group exhibited day switching. After removal of the pars intercerebralis, 26.3% beetles showed arrhythmic patterns (N = 19). The number of paraldehyde fuchsin-stained pars intercerebralis cells in the arrhythmic group was significantly reduced compared to in the intact and sham-operated groups. The activity in the pars intercerebralis-removed beetles was significantly higher than that in the control groups. The results show that the optic lobe and at least part of the pars intercerebralis are necessary for circabidian rhythm, and bilateral optic lobes are necessary to maintain regularity of the two-day rhythm in H. parallela. This suggests that a neural circuit of circadian clock cells in the optic lobe to pars lateralis might be evolutionally conserved and used also for the generation of circabidian rhythm.

Forest restoration treatments in a ponderosa pine forest enhance physiological activity and growth under climatic stress.

As the climate warms, drought will increasingly occur under elevated temperatures, placing forest ecosystems at growing risk of extensive dieback and mortality. In some cases, increases in tree density following early 20th-century fire suppression may exacerbate this risk. Treatments designed to restore historical stand structure and enhance resistance to high-severity fire might also alleviate drought stress by reducing competition, but the duration of these effects and the underlying mechanisms remain poorly understood. To elucidate these mechanisms, we evaluate tree growth, mortality, and tree-ring stable-carbon isotope responses to stand-density reduction treatments with and without prescribed fire in a ponderosa pine forest of western Montana. Moderate and heavier cutting experiments (basal area reductions of 35% and 56%, respectively) were initiated in 1992, followed by prescribed burning in a subset of the thinned units. All treatments led to a growth release that persisted to the time of resampling. The treatments had little effect on climate-growth relationships, but they markedly altered seasonal carbon isotope signals and their relationship to climate. In burned and unburned treatments, carbon isotope discrimination (Δ13 C) increased in the earlywood (EW) and decreased in the latewood (LW) relative to the control. The sensitivity of LW Δ13 C to late-summer climate also increased in all treatments, but not in the control. Such increased sensitivity indicates that the reduction in competition enabled trees to continue to fix carbon for new stem growth, even when the climate became sufficiently stressful to stop new assimilation in slower-growing trees in untreated units. These findings would have been masked had we not separated EW and LW. The importance of faster growth and enhanced carbon assimilation under late-summer climatic stress became evident in the second decade post-treatment, when mountain pine beetle activity increased locally, and tree mortality rates in the controls of both experiments increased to more than twice those in their respective treatments. These findings highlight that, when thinning is used to restore historical forest structure or increase resistance to high-severity fire, there will likely be additional benefits of enhanced growth and physiological activity under climatic stress, and the effects may persist for more than two decades.

Pest management and yield in spring oilseed rape without neonicotinoid seed treatments

Use of neonicotinoid insecticides as seed treatments has been prohibited in the EU. As a consequence, concerns of lost production have been raised among producers. It remains, however, unclear to what extent the ban has increased pest attacks and crop damage, and reduced yield and farm profit. It is also unclear to what extent alternative, non-chemical options can protect crops. Flea beetles (Chrysomelidae: Alticini) are the main pests targeted by insecticide seed treatments in spring oilseed rape (Brassica napus L.). Over three years, we conducted 23 field experiments in which we compared seeds treated with neonicotinoids with untreated seeds, grown at normal or doubled sowing rates. The experiments were established during a range of sowing times at the same time as the hosting farmer sowed, which also allowed us to assess the impact of sowing date. We measured flea beetle activity density, crop plant density, cotyledon damage, crop yield and relative economic performance. Flea beetle activity density was eight times higher in 2014 than in 2016, with intermediate activity in 2015. Neonicotinoid seed treatment, increased sowing rate and an earlier sowing date all reduced crop damage. Seed treatment decreased crop yield loss by 521 kg ha−1 and relative profit loss by 144 Euro ha−1 in 2014, but had no effect on yield or profit in 2015–2016. Increased sowing rate did not affect yield, but decreased profit in 2015 (−138 Euro ha−1) and 2016 (−114 Euro ha−1), mainly due to higher costs for seed. Earlier sowing date was consistently associated with higher yield and profit. Our results put prophylactic seed treatments in question, as they gave lower yield losses in only one year out of three. Earlier sowing and somewhat higher sowing rate emerge as viable alternative pest management practices. Because management outcomes depended on pest pressure, which varied from year to year, crop damage prognosis tools are needed based on improved understanding of the population ecology of crop pests, to support the growers’ decisions and avoid unnecessary use of insecticides.

Fine spatial-scale variation in scavenger activity influences avian mortality assessments on a boreal island.

Bird-window collisions are the second leading cause of human-related avian mortality for songbirds in Canada. Our ability to accurately estimate the number of fatalities caused by window collisions is affected by several biases, including the removal of carcasses by scavengers prior to those carcasses being detected during surveys. We investigated the role of scavenger behavior in modifying perceived carcass removal rate while describing habitat-specific differences for the scavengers present in a relatively scavenger-depauperate island ecosystem. We used motion activated cameras to monitor the fate of hatchling chicken carcasses placed at building (under both windows and windowless walls) and forest (open and closed canopy) sites in western Newfoundland, Canada. We recorded the identity of scavengers, timing of events, and frequency of repeat scavenging at sites. Using 2 treatments, we also assessed how scavenging varied with 2 levels of carcass availability (daily versus every third day). Scavenger activities differed substantially between forest and building sites. Only common ravens (Corvus corax) removed carcasses at building sites, with 25 of 26 removals occurring under windows. Burying beetles (Nicrophorus spp.) dominated scavenging at forest sites (14 of 18 removals), completely removing carcasses from sight in under 24 hours. Availability had no effect on removal rate. These findings suggest that ravens look for carcasses near building windows, where bird-window collision fatalities create predictable food sources, but that this learning preceded the study. Such behavior resulted in highly heterogeneous scavenging rates at fine spatial scales indicating the need for careful consideration of carcass and camera placement when monitoring scavenger activity. Our observations of burying beetle activity indicate that future studies investigating bird collision mortality near forested habitats and with infrequent surveys, should consider local invertebrate community composition during survey design. The high incidence of invertebrate scavenging may compensate for the reduced vertebrate scavenger community of insular Newfoundland.

Canopy cover is a key factor to preserve the ecological functions of dung beetles in the southern Atlantic Forest

In general, livestock activities affect the diversity and ecological functions of dung beetles. However, some practices associated with tree retention could reduce this problem while maintaining productivity. The objective of this study was to explore the influence of canopy cover on dung beetle biomass, their burial activity and changes in soil conditions associated with this activity, in the southern Atlantic Forest of Argentina. Four habitat types were compared: (i) native forest, (ii) silvopastoral systems with native trees, (iii) silvopastoral systems with exotic trees (Pinus taeda), and (iv) open pastures. Canopy cover, and microclimatic and soil conditions were also evaluated in each habitat type. The native forest and silvopastoral systems (both native and exotic) showed lower temperatures, higher relative humidity, higher electrical conductivity, and higher nitrate (N-NO3) and sand contents than open pastures, which showed opposite microclimatic conditions and higher clay contents. In addition, field experiments using acrylic plastic beads and cow dung were performed to evaluate the burial activity of dung beetles, and its influence on soil properties. Soil samples were collected after 30 days to compare the soil conditions among habitat types. Total burial (>95%) and depth (5–6 cm) of acrylic plastic beads were higher in habitat types with native trees than in livestock systems with exotic trees and open pastures; moreover, dung beetle total biomass was strongly and linearly related to burial activity among habitat types. We observed no direct influence of burial activity on soil properties. Our results support the idea that livestock systems with native trees improve the environmental parameters, biomass and ecological functions of dung beetles compared with silvopastoral systems with exotic trees and open pastures.