Mobile Insects Research Articles

Transect-based trapping for area-wide delimitation of insects.

Typical delimitation trapping survey designs for area-wide (nonlocalized) insect populations are regularly spaced grids, and alternative shapes have not been evaluated. We hypothesized that transect-based designs could give similar detection rates with significantly shorter servicing distances. We used the TrapGrid model to investigate novel "trap-sect" designs incorporating crossed, spoked, and parallel lines of traps, comparing them to a regular grid, in single survey and multiple-site scenarios. We calculated minimum servicing distances and simulated mean probabilities of detecting a pest population, judging overall performance of trap network designs using both metrics. For single sites, trap-sect designs reduced service distances by 65-89%, and most had similar detection probabilities as the regular grid. Kernel-smoothed intensity plots indicated that the best performing trap-sect designs distributed traps more fully across the area. With multiple sites (3 side by side), results depended on insect dispersal ability. All designs performed similarly in terms of detection for highly mobile insects, suggesting that designs minimizing service distances would be best for such pests. For less mobile pests the best trap-sect designs had 4-6 parallel lines, or 8 spokes, which reduced servicing distances by 33-50%. Comparisons of hypothetical trap-sect arrays to real program trap locations for 2 pests demonstrated that the novel designs reduced both trap numbers and service distances, with little differences in mean nearest trap distance to random pest locations. Trap-sect designs in delimitation surveys could reduce costs and increase program flexibility without harming the ability to detect populations.

Microhabitat conditions remedy heat stress effects on insect activity.

Anthropogenic global warming has major implications for mobile terrestrial insects, including long-term effects from constant warming, for example, on species distribution patterns, and short-term effects from heat extremes that induce immediate physiological responses. To cope with heat extremes, they either have to reduce their activity or move to preferable microhabitats. The availability of favorable microhabitat conditions is strongly promoted by the spatial heterogeneity of habitats, which is often reduced by anthropogenic land transformation. Thus, it is decisive to understand the combined effects of these global change drivers on insect activity. Here, we assessed the movement activity of six insect species (from three orders) in response to heat stress using a unique tracking approach via radio frequency identification. We tracked 465 individuals at the iDiv Ecotron across a temperature gradient up to 38.7°C. In addition, we varied microhabitat conditions by adding leaf litter from four different tree species to the experimental units, either spatially separated or well mixed. Our results show opposing effects of heat extremes on insect activity depending on the microhabitat conditions. The insect community significantly decreased its activity in the mixed litter scenario, while we found a strong positive effect on activity in the separated litter scenario. We hypothesize that the simultaneous availability of thermal refugia as well as resources provided by the mixed litter scenario allows animals to reduce their activity and save energy in response to heat stress. Contrary, the spatial separation of beneficial microclimatic conditions and resources forces animals to increase their activity to fulfill their energetic needs. Thus, our study highlights the importance of habitat heterogeneity on smaller scales, because it may buffer the consequences of extreme temperatures of insect performance and survival under global change.

Sources of Fungal Symbionts in the Microbiome of a Mobile Insect Host, Spodoptera frugiperda

The sources of fungal symbionts of insects are not well understood, yet the acquisition and assembly of fungal communities in mobile insect hosts have important implications for the ecology of migratory insects and their plant hosts. To determine potential sources of fungi associated with the fall armyworm (Spodoptera frugiperda), we characterized the fungal communities associated with four different ecological compartments (insects, infested leaves, uninfested leaves, and soil) and estimated the contributions of each of these potential sources to the insect’s fungal microbiome. Results show that insect fungal community composition was distinct from and more varied than the composition of fungal communities in the environment of those insects (plants and soil). Among the sources evaluated, on average we found a surprisingly large apparent contribution from other congeneric S. frugiperda insect larvae (ca. 25%) compared to the contribution from soil or plant sources (< 5%). However, a large proportion of the insect microbiome could not be attributed to the sampled sources and was instead attributed to unknown sources (ca. 50%). Surprisingly, we found little evidence for exchange of fungal taxa, with the exception of a Fusarium oxysporum and a Cladosporium sp. OTU, between larvae and the infested leaves on which they fed. Together, our results suggest that mobile insects such as S. frugiperda obtain their fungal symbionts from a variety of sources, not limited to plants and soil, but including conspecific insects and other unsampled environmental sources, and that transmission among insects may play an important role in acquisition of fungal symbionts.

Temperature Sensing Shape Morphing Antenna (ShMoA).

Devices that can morph their functions on demand provide a rich yet unexplored paradigm for the next generation of electronic devices and sensors. For example, an antenna that can morph its shape can be used to adapt communication to different wireless standards or improve wireless signal reception. We utilize temperature-sensitive shape memory alloys (SMA) to realize a shape morphing antenna (ShMoA). In the designed architecture, multiple conjoined shape memory alloy sections form the antenna. The shape morphing of this antenna is achieved through temperature control. Different temperature threshold levels are used for programming the shape. Besides its conventional use for RF applications, ShMoA can serve as a multi-level temperature sensor, analogous to thermoreceptors in an insect antenna. ShMoA essentially combines the function of temperature sensing, embedded computing for detection of threshold crossings, and radio frequency readout, all in the single construct of a shape-morphing antenna (ShMoA) without the need for any battery or peripheral electronics. The ShMoA can be employed as bio-inspired wireless temperature sensing antennae on mobile robotic flies, insects, drones and other robots. It can also be deployed as programmable antennas for multi-standard wireless communication.

Predatory Ungulates? Interactions Between Large Mammalian Herbivores and Plant‐Dwelling Arthropods

Photo 1. Herds grazing in the Serengeti (Tanzania): how many arthropods are consumed? Photograph credit: Moshe Inbar. Photo 2. Cattle grazing: mobile insects, aggressive (e.g., ants), or noxious species (such as the caterpillars of Ocnogyna loewii) were not eaten by cattle during grazing. Photograph credit: Tali Berman. These photographs illustrate the article “Revealing cryptic interactions between large mammalian herbivores and plant-dwelling arthropods via DNA metabarcoding” by Tali S. Berman and Moshe Inbar published in Ecology. https://doi.org/10.1002/ecy.3548.

Quantifying the Role of Ground Beetles for the Dispersal of Fusarium and Alternaria Fungi in Agricultural Landscapes.

The spread by arthropods (zoochory) is an essential dispersal mechanism for many microorganisms, like plant pathogens. Carabid beetles are very abundant and mobile ground-dwelling insects. However, their role in the dispersal of economically relevant phytopathogens, like Fusarium and Alternaria fungi is basically unknown. We quantified the total fungal, Fusarium, and Alternaria load of carabid species collected in the transition zones between small water bodies and wheat fields by screening (i) their body surface for fungal propagules with a culture-dependent method and (ii) their entire bodies for fungal DNA with a qPCR approach. The analysis of entire bodies detects fungal DNA in all carabid beetles but Alternaria DNA in 98% of them. We found that 74% of the carabids carried fungal propagules on the body surface, of which only half (49%) carried Fusarium propagules. We identified eight Fusarium and four Alternaria species on the body surface; F. culmorum was dominant. The fungal, Fusarium and Alternaria, load differed significantly between the carabid species and was positively affected by the body size and weight of the carabids. Carabid beetles reveal a remarkable potential to disseminate different fungi. Dispersal by ground-dwelling arthropods could affect the spatial-temporal patterns of plant disease and microorganisms in general.

Cryptic local adaptation of the herbivorous ladybird beetle Henosepilachna pustulosa in the ability to use the thistle Cirsium boreale

AbstractLocal adaptation to different host plants is important in the diversification of phytophagous insects. Thus far, much evidence of the local adaptation of insects with respect to host use at the physiological level has been gathered from systems involving less mobile insects and/or divergent hosts such as plants belonging to different families or genera. On the other hand, the prevalence of such local adaptation of insects with moderate or high dispersal ability to the intraspecific variation of herbaceous hosts is largely unknown. In the present study, we examined the occurrence and degree of local adaptation of the herbivorous ladybird beetle Henosepilachna pustulosa (Kôno) (Coleoptera: Coccinellidae) to its primary host, the thistle Cirsium boreale Kitam. (Asteraceae), through reciprocal laboratory experiments using beetles and thistles from three locations with a range of approximately 200 km. Concerning the larval developmental ability, obvious patterns of local adaptation to the thistles from respective natal locations were detected, at least in some combinations of beetle populations. Similar tendencies were detected concerning adult feeding acceptance, although the statistical support was somewhat obscure. Overall, our results indicate that the degree of local adaptation of insect species with moderate dispersal ability to conspecific herbaceous hosts is occasionally as strong as that involving less mobile insects and/or heterospecific hosts, indicating the potential of such cryptic local adaptation to promote ecological/genetic differentiation of phytophagous insect populations.

Diel activity patterns and arrestment behaviour in host associations of green mirids (Creontiades dilutus).

Many plant bugs (Miridae) are generalist herbivores that feed on multiple host species. The reasons these bugs move across hosts and the behavioural mechanisms responsible for their retention at specific hosts remain elusive. Green mirids (Creontiades dilutus) are endemic to Australia. These insects are important pests of cotton (Gossypium hirsutum) and even in low numbers can cause substantial damage to crops. These bugs are also present in relatively much higher numbers on pigeon pea (Cajanus cajan) planted alongside cotton fields, and evidence shows they move across these crops in both directions. Observations of these highly mobile insects in the field are challenging, but indirect evidence suggests that they may be nocturnal. This study evaluated: (1) the diel (24 h) period in which C. dilutus adults were most active, (2) whether they respond to plant volatiles immediately prior to landing on host substrates, and (3) if their presence on a host is in response to attraction or arrestment cues. The results suggest that C. dilutus bugs are typically most active early in the evenings, after remaining motionless during the day (unless disturbed). Their movement (at night) was arrested by hosts prior to touching plant tissues. There was no evidence to suggest that these bugs are attracted by volatiles beyond 2 cm. These outcomes demonstrate that insect behaviours need to be investigated within their typical activity periods, and that arrestment cues possibly play a central role in the host finding process of generalist C. dilutus and probably, therefore, other mirid species.

Abundance and diversity of pollinators on green roofs are affected by environmental factors

Bees provide a variety of ecological services for urban ecosystems, while green roofs can also be of high value to bees through providing habitats and foraging sites. In this study, four hypotheses about impacts on abundance and diversity of pollinators were proposed from the roof and the surrounding environment. The evidences revealed that the height of the building affected the diversity of some bee species; increasing proportions of surrounding green space helped to increase abundance of bees and wasps; the colonies of bees were significantly affected by habitat connectivity, a frequent movement of bees and other mobile insects between roofs and ground guaranteed pollination of plants; plentiful plants combination was better than a single species in roof ecosystem services, and native forbs were beneficial for pollinations and foraging of pollinators; using fine substrate on green roofs may have a greater ecological value than common soil.

Density Dependence of Egg Recruitment and Moth Dispersal in Spruce Budworms

Egg recruitment quantifies the relative importance of realized fecundity and migration rates in the population dynamics of highly mobile insects. We develop here a formal context upon which to base the measurement and interpretation of egg recruitment in population dynamics of eastern and western spruce budworms, two geographically separated species that share a very similar ecology. Under most circumstances, per capita egg recruitment rates in these budworms are higher in low-density populations and lower in high-density populations, relative to the regional mean: Low-density populations are nearly always migration sinks for gravid moths, and dense populations nearly always sources. The slope of this relationship, measured on a log scale, is negatively correlated with migration rate, and ranges between 0 and −1. The steeper the slope, the more marked net migration. Using our western spruce budworm observations, we found strong evidence of density-dependent emigration in budworms, so migration is not simply a random perturbation in the lagged, density-dependent stochastic process leading to budworm outbreaks. It is itself statistically and biologically density-dependent. Therefore, moth migration is a synchronizing factor and a spread mechanism that is essential to understanding the development and expansion of spruce budworm outbreaks at regional scales in the boreal forests of North America.

Using host-associated differentiation to track source population and dispersal distance among insect vectors of plant pathogens.

Small, mobile insects are notoriously challenging to track across landscapes and manage in agricultural fields. However, genetic differentiation among insect populations and host plants acquired through host‐associated differentiation could be exploited to infer movement within crop systems and damage potential. Although many insects exhibit host‐associated differentiation, management strategies for insect vectors of plant pathogens assume a homogenous population. Nevertheless, phenotypic changes derived from host‐associated differentiation could manifest in altered behavior or physiology affecting the likelihood of vector–pathogen–plant interactions, or the subsequent efficiency of pathogen transmission. We used SNPs to assess genotypic structure and host‐associated differentiation in the cowpea aphid, Aphis craccivora Koch (Hemiptera: Aphididae). To do so, we sampled A. craccivora across the Midwestern United States. from two host plants, alfalfa (Medicago sativa) and black locust (Robinia pseudoacacia)—putative source populations for winged migrants. Simultaneously, we sampled winged A. craccivora landing in pumpkin fields where they transmit viruses. Structure analyses supported host‐associated differentiation by identifying two major genotypic groups: an alfalfa group containing a single multilocus genotype and a locust group containing all others. Winged locust‐group aphids landed at a much greater magnitude within focal fields during year 2 than year 1, while those in the alfalfa group remained fairly consistent. Spatial autocorrelation analyses indicated locust‐group aphid movement was characterized by small‐scale dispersal during year 2, likely originating from populations within 10 km. We also detected strong temporal differences in colonization from the two host plants. Early in the summer, most winged aphids (79.4%) derived from the locust group, whereas late in the summer more (58.3%) were from the alfalfa group. Because early crop growth stages are more susceptible to damage from aphid‐vectored viruses, these data implicate locust as the more important source and illustrate how host‐associated differentiation can be used to track dispersal and inform management of heterogeneous pest populations.

Food mobility and the evolution of grasping behaviour: a case study in strepsirrhine primates

Manual grasping is widespread among tetrapods but is more prominent and dexterous in primates. Whether the selective pressures that drove the evolution of dexterous hand grasping involved the collection of fruit or predation on mobile insects remains an area of debate. One way to explore this question is to examine preferences for manual versus oral grasping of a moving object. Previous studies on strepsirrhines have shown a preference for oral grasping when grasping static food items and a preference for manual grasping when grasping mobile prey such as insects, but little is known about the factors at play. Using a controlled experiment with a simple and predictable motion of a food item, we tested and compared the grasping behaviours of 53 captive individuals belonging to 17 species of strepsirrhines while grasping swinging food items and static food items. The swinging motion increased the frequency of hand-use for all individuals. Our results provide evidence that the swinging motion of the food is a sufficient parameter to increase hand grasping in a wide variety of strepsirrhine primates. From an evolutionary perspective, this result gives some support to the idea that hand-grasping abilities evolved under selective pressure associated with the predation of food items in motion. Looking at a common grasping pattern across a large set of species, this study provides important insight into comparative approaches to understanding the evolution of the hand grasping of food in primates and potentially other tetrapod taxa.

Local vs. landscape characteristics differentially shape emerging and circulating assemblages of carabid beetles in agroecosystems

Knowledge of biodiversity in agroecosystems is crucial for understanding ecosystem functioning, but requires accurate sampling methods. Most studies of ground-active arthropods in fields rely on activity-density measurement using pitfall traps. Assemblages locally observed are likely to composed both resident and immigrant species, and that is especially true for arthropods exhibiting high dispersal abilities and/or larval development that is very different from the adults. Using a spatially paired design of emerging traps vs pitfall traps in 10 pairs of organic (OF) and conventional (CF) fields, we quantified how circulating and emerging assemblages of an abundant taxa of mobile and holometabolous insects, carabid beetles, were impacted by different field farming systems and landscape characteristics. Field sampling was carried out during 5 months of 2015 in Brittany (Western France), during which 24,726 individuals belonging to 85 species were captured. Our results revealed that the number of individuals and species of both emerging and circulating assemblages were significantly higher in OF compared to CF, reinforcing the idea that OF provide more suitable conditions for both resident and mobile arthropods. Landscape and local factors had a similar influence on emerging carabid assemblages, whereas local factors were stronger drivers for circulating carabid assemblages. This study highlights the importance of distinguishing resident (emergent) and mobile (circulating) individuals when assessing the differential role of local vs. landscape factors in community assembly. It also reinforces the idea that spatiotemporal movements of predatory arthropods are impacted by spillover from and between croplands, resulting in source-sink dynamics with habitat quality being the major driver of these processes.

High degree of philopatry is required for mobile insects used as local indicators in biodiversity studies

Local changes in land use and climatic conditions provoke transformations of habitats and therefore, distribution changes of species in the landscape. Different insect groups are repeatedly used as indicators of local ecological conditions in biodiversity research. Here we suggest that only highly philopatric groups can be relevant indicators pointing to differences in ecological conditions among spatially close habitats. For our study in open agriculture landscape, we chose aculeate Hymenoptera and hoverflies as two insect, mostly pollinator groups differing in their degree of philopatry within the registered pool of our survey where hoverflies were represented by common generalist species showing high mobility. We tested if these groups appeared in significantly different species numbers in two most contrasting habitats typical for the European open agriculture landscape: patches of flower-rich, semi-natural habitats around fields with a variety of nesting sites and wheat fields in proximity that represented a non-viable agricultural habitat with no nesting and foraging opportunities. For this purpose, comparison of results from attractant based (pan traps) and observational (transect walks) methods were used. Philopatric species were detected in significantly different species numbers in the two habitat types using both methods. In contrast, highly mobile non-philopatric species showed a mixed pattern. We assume that these species can be attracted at any place if containing a suitable attractant (flowers or pan traps in this case) what may not indicate their actual living in the habitat.

Does Landscape Complexity and Semi-Natural Habitat Structure Affect Diversity of Flower-Visiting Insects in Cucumber Fields?

Presence of insects in agricultural habitat is affected by the surrounding circumstances such as the complexity and structure of landscape. Landscape structure is often formed as a consequence of the fragmentation of semi-natural habitat, which can negatively affect species richness and abundance of insects. This study was aimed to study the effect of complexity and structure of landscape on the diversity, abundance and traits of flower-visiting insects in cucumber fields. This study was conducted in cucumber fields surrounded by other agricultural crops, shrubs, semi-natural habitat and housing area, in Bogor, Cianjur and Sukabumi regencies, West Java, Indonesia. In a total of 16 agricultural areas, complexity and parameter of landscape especially class area (CA), number of patches (NumP), mean patch size (MPS), total edge (TE), and mean shape index (MSI) of seminatural habitats were measured. Sampling of flower-visiting insects was conducted using scan sampling methods. The result showed that landscape complexity affected species richness (but not abundance and trait) of flower-visiting insects both for mobile and less-mobile insects. Flower-visiting insects also responded differently to landscape structure. Species richness, abundance and variation of body size of mobile insects were affected by structure of semi-natural habitat.

Planting of neonicotinoid‐treated maize poses risks for honey bees and other non‐target organisms over a wide area without consistent crop yield benefit

Summary Neonicotinoid insecticides are routinely used as seed treatments on most grain and oilseed crops in the USA, yet the extent and likelihood of spread of insecticide residues during planting has not previously been quantified. Honey bees, Apis mellifera, are highly mobile and highly sensitive to neonicotinoid residues, presenting an opportunity to estimate non‐target exposures to neonicotinoids in mobile insects. We measured neonicotinoid dust drift during maize sowing and used sites of maize fields, apiary locations and honey bee foraging radii to estimate likelihood of forager exposure. We performed a concurrent multi‐year field assessment of the pest management benefits of neonicotinoid‐treated maize. Our results indicate that over 94% of honey bee foragers throughout the state of Indiana are at risk of exposure to varying levels of neonicotinoid insecticides, including lethal levels, during sowing of maize. We documented no benefit of the insecticidal seed treatments for crop yield during the study. Synthesis and applications. We demonstrate movement of neonicotinoid residues well beyond planted fields occurs during maize sowing in Indiana. Based on locations of maize fields and apiaries in the state, the likelihood of neonicotinoid exposure for foraging honey bees is high. Other non‐target organisms are also likely to encounter neonicotinoid residues; we conservatively estimate that deposition of neonicotinoid residues on non‐target lands and waterways will occur on over 42% of the state of Indiana during the period of maize sowing. However, we also demonstrate that the risk to pollinators and other non‐target organisms may be rapidly and dramatically reduced without yield penalties, by aligning use rates of neonicotinoid insecticides with pest incidence.

The first report of massive infestation with Lipoptena Cervi ( Diptera: Hippoboscidae ) in Roe Deer ( Capreolus Capreolus ) in Iasi county, N-E of Romania

ABSTRACT Investigations of four roe deer corpses were carried out from May until October 2014, in the Veterinary Forensic Laboratory and in the Parasitic Diseases Clinic, in the Iasi Faculty of Veterinary Medicine. The roe deer were harvested by shooting during the trophy hunting season. The clinical examination of the shot specimens revealed the presence of a highly consistent number of extremely mobile apterous insects, spread on the face, head, neck, lateral body parts, abdominal regions, inguinal, perianal and, finally, all over the body. The corpses presented weakening, anemia and cutaneous modification conditions. Several dozen insects were prelevated in a glass recipient and preserved in 70º alcoholic solution in order to identify the ectoparasite species. The morphological characteristics included insects in the Diptera order, Hippoboscidae family, Lipoptena cervi species. These are highly hematophagous insects that by severe weakening are affecting the game health and trophy quality. Histological investigations of the skin revealed some inflammatory reactions caused by ectoparasite Lipoptena cervi. Lipoptena cervi was identified for the first time in Iasi County, Romania.

Are floating algal mats a refuge from hypoxia for estuarine invertebrates?

Eutrophic aquatic habitats are characterized by the proliferation of vegetation leading to a large standing biomass that upon decomposition may create hypoxic (low-oxygen) conditions. This is indeed the case in nutrient impacted estuaries of Prince Edward Island, Canada, where macroalgae, from the genus Ulva, form submerged ephemeral mats. Hydrological forces and gases released from photosynthesis and decomposition lead to these mats occasionally floating to the water’s surface, henceforth termed floating mats. Here, we explore the hypothesis that floating mats are refugia during periods of sustained hypoxia/anoxia and examine how the invertebrate community responds to it. Floating mats were not always present, so in the first year (2013) sampling was attempted monthly and limited to when both floating and submerged mats occurred. In the subsequent year sampling was weekly, but at only one estuary due to logistical constraints from increased sampling frequency, and was not limited to when both mat types occurred. Water temperature, salinity, and pH were monitored bi-weekly with dissolved oxygen concentration measured hourly. The floating and submerged assemblages shared many of the same taxa but were statistically distinct communities; submerged mats tended to have a greater proportion of benthic animals and floating mats had more mobile invertebrates and insects. In 2014, sampling happened to occur in the weeks before the onset of anoxia, during 113 consecutive hours of sustained anoxia, and for four weeks after normoxic conditions returned. The invertebrate community on floating mats appeared to be unaffected by anoxia, indicating that these mats may be refugia during times of oxygen stress. Conversely, there was a dramatic decrease in animal abundances that remained depressed on submerged mats for two weeks. Cluster analysis revealed that the submerged mat communities from before the onset of anoxia and four weeks after anoxia were highly similar to each other, indicating recovery. When mobile animals were considered alone, there was an exponential relationship between the percentage of animals on floating mats, relative to the total number on both mat types, and hypoxia. The occupation of floating mats by invertebrates at all times, and their dominance there during hypoxia/anoxia, provides support for the hypothesis that floating mats are refugia.

Earlier activity of Drosophila suzukii in high woodland landscapes but relative abundance is unaffected

Natural habitats can affect the population dynamics of mobile insects, and the spatial and temporal effects on agricultural pest species may be especially relevant for tailoring management strategies to the farm context. Drosophila suzukii Matsumura (Diptera: Drosophilidae) is suspected to utilize woodland habitat for wild hosts and overwintering with possible adverse effects of woods on adjacent fruit crops. A two-year study in the Upper Midwest, USA examined if the amount of woodland in the landscape affects early season activity and relative abundance of D. suzukii in raspberry fields. Thirty-five farms were selected to span a gradient of low-to-high woodland area at the 1.5 km scale. The first capture of D. suzukii occurred earlier at farms in high woodland landscapes. However, woodland area was not correlated with metrics of D. suzukii abundance in raspberry (growth rate, peak, fall, or total fly catch) suggesting similar crop infestation risk across landscapes. However, woodland area was negatively correlated with fall fly catch in the adjacent woods and significantly more flies were captured in the woods than raspberry. This study suggests woodland landscapes affect early season crop risk and the high numbers of D. suzukii in the woods have implications for understanding overwintering.

Commonly Used Intercarcass Distances Appear to Be Sufficient to Ensure Independence of Carrion Insect Succession Pattern

Forensic entomology field researchers have typically placed experimental carcasses ≤50 m apart. Direct observations indicate that this intercarcass distance sufficiently prevents cross contamination by crawling larvae, but seems insufficient to prevent highly mobile adult insects from detecting or visiting more than one carcass. It would be valuable if minimum intercarcass distance ensured independence of replicates, because this is an assumption of common statistical analyses. For 32 domestic pig carcasses exposed during two consecutive summers (range of intercarcass distance 30 to >300 m), possible relationships between: 1) average distance to another carcass and aspects of the succession patterns of forensically important species and 2) intercarcass distance and community similarity indices were estimated with regression analyses. In addition, minimum intercarcass distance was investigated through semivariogram analyses of aspects of the succession interval as well as community similarity indices. Pairwise similarity of time to first occurrence was the only variable that displayed a consistent, in this case negative, relationship to intercarcass distance, although not statistically significant for any single analysis. Semivariogram analysis suggested that under the conditions used for our experiment commonly used intercarcass distances are satisfactory to ensure independence of carcasses.