Diel variation in the difference in air temperature between the forest edge and interior in the Usambara Mountains, Tanzania

The difference in air temperature between the forest edge and interior was simultaneously compared at ten sites at 2‐h intervals over a 229‐day period in the East and West Usambara Mountains in Tanzania. Measurements were recorded with data loggers placed 1.5 m above the ground on the shaded side of trees and positioned 1–2 and 100 m from the forest edge. The difference in air temperature between the forest edge and interior varied regularly over a 24‐h period with mean maximum difference in air temperatures of 0.85°C occurring at 15:00 h and mean minimum diel difference in air temperature of 0.02°C occurring at 21:00 h. Diel variation in the difference in air temperature between the forest edge and interior varied little by season and was unrelated to elevation.     

Fragmentation and Alteration of Seed Dispersal Processes: An Initial Evaluation of Dung Beetles, Seed Fate, and Seedling Diversity1

Given current accelerated trends of tropical land conversion, forest fragments are being incorporated into many conservation programs. For investing in fragments to be a viable conservation strategy, forest fragments must maintain their ecological integrity over the long term. Based on fieldwork in 22 forest fragments in the crater lakes region of western Uganda and in the continuous forest of Kibale National Park, we examined (1) seed predation on experimentally dispersed seeds, (2) abundance and composition of the dung beetle community that may play a major role in removing seeds from sites of high seed predation, and (3) compared the fragments’ seedling community composition to adult tree community composition and the seedling community in continuous forest. First, the rate of seed removal at experimental stations was lower in forest fragments (85% remaining after 1 day) than at stations in the continuous forest (79% remaining) and the probability of stations being discovered by seed predators was lower in fragments (23%) than in the intact forest (41%). Second, there was a 62 percent decline in fragment dung beetle abundance. The magnitude of this decline varied among dung beetle guilds that process dung and seeds in different fashions. The abundance of large rollers that move large seeds away from sites of defecation did not differ, but medium and smaller rollers and burying beetles that process small and medium‐sized seeds were less common in the fragments than in the intact forest. Finally, we compared the seedling community composition relative to adult tree community composition by identifying all adult trees in each fragment and by sampling the composition of the seedling community. We found some evidence to suggest that there was movement of seeds among forest fragments by large‐bodied dispersers, particularly chimpanzees (Pan troglodytes) and hornbills (Ceratogymna subcylindricus).     

Species diversity and community structure of rove beetles (Coleoptera: Staphylinidae) attracted to dung of sika deer in coniferous forests of southwest Japan

Insect communities of mammal dung have been known as excellent model ecosystems for scientific study. Ecological surveys of diversity and seasonal patterns of coprophilous rove beetles in relation to wild mammals have rarely been conducted, although the high potential species diversity and abundance of the rove beetles are known. In order to investigate biodiversity of these beetles, we analyzed species composition, abundance, feeding guild and seasonality of rove beetles that were attracted to sika deer Cervus nippon dung by using dung‐baited pitfall traps for a 1.5‐year study in two plantations (cypress, cedar) and one secondary natural forest (pine) in Fukuoka Prefecture, southwest Japan. Consequently, saprophagous Anotylus sp. (Oxytelinae) was dominant in all forests. Analyses of feeding guild structure showed the number of individuals were dominated by saprophagous beetles, but the number of species were dominated by predatory beetles. Seasonal effects suggested that the species richness and abundance of rove beetles are possibly regulated by scarabaeoid dung beetles. These findings feature one example of a coprophilous rove beetle community.     

Dispersión Primaria de Semillas por Primates y Dispersión Secundaria por Escarabajos Coprófagos en Tikal,Guatemala1

We linked primary dispersal by spider monkeys (Ateles geoffroyi) and howler monkeys (Alouatta pigra) to post‐dispersal seed fate by studying the effects of dung type and defecation pattern on secondary seed dispersal by dung beetles. First, we described the defecation patterns for both primate species. Howler monkeys generally defecated in groups (88% of observed defecations), with each individual producing on average 31 g of dung, resulting in a large area of the forest floor (31 m²) covered by large amounts of dung (clumped spatial pattern). Spider monkeys generally (96% of observed defecations) defecated individually, each individual producing an average of 11 g of dung, resulting in a small area of the forest floor (2 m²) covered by small amounts of dung (scattered spatial pattern). Secondly, we captured dung beetles using as bait the dung of both primate species, to detect differences in the assemblages of these secondary seed dispersers attracted to the dung of both primates. More individual dung beetles, but not more species, were attracted to howler monkey dung than to spider monkey dung. Finally, we assessed experimentally (using plastic beads as seed mimics) how dung type (Ateles vs. Alouatta) and defecation pattern (scattered vs. clumped) affect secondary seed dispersal by dung beetles. We found that post‐dispersal seed fate was affected by dung type, with more seeds being buried when present in howler monkey dung, than in spider monkey dung, but was not affected by defecation pattern. It is important to consider post‐dispersal processes, such as secondary seed dispersal by dung beetles, when comparing species of primary dispersers.     

Diet of the Silvery-cheeked Hornbill Bycanistes brevis during the breeding season in the East Usambara Mountains,Tanzania

The breeding season diet and nesting characteristics of the Silvery-cheeked Hornbill Bycanistes brevis are poorly known. To further understand these aspects of the breeding biology of this hornbill species, 14 nests were studied in and around Amani Nature Reserve located in the East Usambara Mountains, Tanzania. Nesting tree species were identified and the diet composition of nesting hornbills was evaluated between July and November 2001. The ejecta from each nest were collected, inventoried, identified (as completely as possible) and enumerated. Food items were categorised as plant, vertebrate or invertebrate. Plants, represented largely by fruits, were the dominant food type (n = 861), followed by invertebrates (n = 306; mainly millipedes and beetles), and vertebrates (n = 15; mainly smaller birds and chameleons). A comparison of results from the current study to other nesting observations made approximately seven decades earlier in the same area suggest that (1) the invasive tree species Maesopsis eminii, which was the most common food type consumed (n = 4 539 seeds), has become a favoured new food source in the breeding season, and (2) the breeding season appears to have shifted to an earlier period, potentially due to the fruiting phenology and abundance of Maesopsis eminii.     

Short‐term assessment of dung beetle response to carbosulfan treatment against desert locust in Sudan

The beneficial role of dung beetles (Coleoptera: Scarabaeidae) is well known. Potential risks to these beetles from the widespread use of insecticides against the desert locust, a significant plant pest in Africa, the Near East and South West Asia, have not been studied previously. Short‐term responses of dung beetles to carbamate carbosulfan (Marshal®, ultra low‐volume formulation, 100 g active ingredient ha^?1) were assessed during desert locust control operations at five sites within two major biotopes: Acacia tortilis shrubland and cultivated wetland; on the Red Sea Coast of Sudan. The study took place during January–February 2004. At each site, fresh dung from Zebu cows was placed in areas targeted for desert locust control. Dung pats were placed in plots in two areas and left for 24 h, before and after insecticide application. Beetles were extracted by floatation. There was a significant decrease in abundance between the pre‐ and post‐spray period in treated areas for the Scarabaeinae species Onthophagus margaritifer (a dark colour morph). In contrast, it was found that Aphodius lucidus and beetles at the subfamily level of Aphodiinae increased in numbers after insecticide treatment. Mortality and sublethal impacts as well as a repellent effect of the insecticide may explain the decrease in Onthophagus margaritifer, while the increase in Aphodiinae beetles could be an indirect response to lower numbers of Scarabaeinae beetles in competing for the same resource. These organisms and the applied methodology may be useful for environmental monitoring of desert locust control, thus further studies are suggested. The assessment also revealed a marked difference between the two biotopes with high abundance and species richness of dung beetles in A. tortilis shrubland, while these measures were low in the cultivated wetland. Five new species of dung beetles for Sudan were found in this study.     

Forest complexity drives dung beetle assemblages along an edge-interior gradient in the southwest Amazon rainforest

1. The habitat heterogeneity hypothesis predicts that heterogeneous habitats may provide more niches and diverse ways of exploiting environmental resources, thereby allowing more species to coexist, persist and diversify. 2. We aimed to investigate how an edge-interior gradient related to forest complexity influences species composition, abundance and richness of dung beetles in the western Amazon rainforest. We expected dung beetle abundance and richness to increase along the forest edge-interior gradient, in accordance with the habitat heterogeneity hypothesis. We also expected strong changes in species composition driven by species turnover in the forest interior and nestedness along the forest edges. We sampled dung beetles using baited pitfall traps across an edge-interior gradient. We also assessed the variation in forest features along the edge-interior gradient to identify changes in forest complexity. 3. Both species richness and abundance of dung beetles increased along the forest edge-interior, following the gradient of forest complexity. The Sorensen dissimilarity of dung beetle assemblages was higher among sampling units placed near the forest edge, although neither turnover, nor nestedness was different between the extremes of the forest edge-interior gradient. There was a clear compositional change along the edge-interior gradient mostly driven by species turnover. Individual indicator value analysis revealed that species were strongly associated with the forest interior conditions. 4. The simplification of the Amazon rainforest near clearings causes compositional changes in dung beetle assemblages. These changes are characterised by species-poor and low-abundance assemblages and may impair dung beetle ecological functions and therefore forest recovery.     

Tanzanian Forest Edge Microclimatic Gradients: Dynamic Patterns1

Air temperature, vapor pressure deficit, and light intensity microclimatic gradients were examined along four forest edge and four paired forest interior transects in the East and West Usambara Mountains, Tanzania. Between 14 August 1995 and 11 August 1998, 287, 282, and 196 air temperature, vapor pressure deficit, and light intensity gradients, respectively, were measured along the four forest edge and four interior transects. The relationship between microclimate and distance from the forest edge was examined using piecewise linear regression. All microclimatic gradients were classified into one of nine shapes based on the sign and the size of the two estimated slopes. The relative frequency in the shapes of 65 percent of air temperature gradients, 52 percent of vapor pressure deficit gradients, and 62 percent of light intensity gradients along forest edge transects exceeded the relative frequency of these same shapes along forest interior transects, indicating that a majority of the forest edge microclimatic gradients measured were influenced by edge effects. Yet this result also indicated that approximately one‐third of all air temperature and light intensity gradients and nearly one‐half of all vapor pressure deficit gradients recorded during this study were affected by factors independent of edge effects per se, and that forest edge microclimatic gradients were temporally nonconstant. For air temperature and vapor pressure deficit gradients, low spatial but high temporal variation existed in estimated edge width and the relative change in microclimate between the forest edge and interior. For light intensity gradients, both high spatial and temporal variability characterized estimated edge width and relative change in microclimate between the forest edge and interior. The pooled mean edge width and relative change in microclimate between die forest edge and interior across the four forest edge transects for air temperature, vapor pressure deficit, and light intensity gradients were 94.1 m and 2.00°C, 82.6 m and 0.29 kPa, and 60.5 m and 10.6 joules/sec/m², respectively. These results suggest that forest edge microclimatic gradients in general may be inherently dynamic and nonconstant.     

Tamarins and Dung Beetles: An Efficient Diplochorous Dispersal System in the Peruvian Amazonia

Dung beetles fulfill several key functions in ecosystems but their role as secondary seed dispersers is probably one of the most complex ones. Various factors, such as seed characteristics, dispersal pattern induced by the primary disperser, season, and habitat, can affect the seed–beetle interaction. Particularly little is known about the fate of seeds primarily dispersed in small feces. The aim of this study was to investigate the effects of these factors on the dung beetle community (species composition, number and size of individuals) and its consequences on burial occurrence and depth of seeds primarily dispersed by two tamarin species. We captured dung beetles in a Peruvian rain forest with 299 dung‐baited pitfall traps to characterize the dung beetle community. Seed burial occurrence and depth were assessed by marking in situ 551 dispersed seeds in feces placed in cages. Among these seeds, 22.5 percent were buried by dung beetles after 2 d. We observed a significant effect of the amount of dung, season, time of deposition, and habitat on the number of individuals and species of dung beetles, as well as on seed burial occurrence and depth, while the tamarin species significantly influenced only the number and the size of dung beetles. This seed dispersal loop is particularly important for forest regeneration: small to large seeds dispersed by tamarins in secondary forest can be buried by dung beetles. These seeds can thus benefit from a better protection against predation and a more suitable microenvironment for germination, potentially enhancing seedling recruitment.     

Effects of Degradation and Replacement of Southern Brazilian Coastal Sandy Vegetation on the Dung Beetles (Coleoptera: Scarabaeidae)

In this paper we address the effects of anthropogenic disturbance and replacement of Brazilian Coastal sandy vegetation (restingas) on dung beetles communities. We sampled dung beetles in the four main vegetative physiognomies of Guriri Island, Espírito Santo State: forest restinga, restinga Clusia, disturbed restinga (from burning events), and pastures. We placed four sets of two pitfall traps (baited with horse and human dung) in four independent areas of each vegetation type, and collected 14,534 individuals of 13 dung beetle species. Neither log₁₀ of individuals nor log₁₀ of species richness were good predictors of restinga disturbance. However, a significant amount of variation in dung beetle abundance and richness could be explained by bait type. Ordination of these sites using hybrid multidimensional scaling revealed a gradient of habitat disturbance from undisturbed restinga samples to pasture. Dung beetle communities along this gradient demonstrated a complete turnover in species composition, from restinga‐specialists to invasive and generalists species respectively. This complete turnover signals the local extirpation of forest‐adapted species in disturbed and converted areas. Only a single dung beetle species in preserved restingas is protected by Brazilian law (Dichotomius schiffleri). Given the extent of the clearing of restinga habitat, the conservation status of dung beetles associated with restinga forest gives cause for concern.     

Convergence Between Dung Beetle Assemblages of a Post-Mining Vegetational Chronosequence and Unmined Dune Forest

Abstract In Maputaland, South Africa vegetative and microclimatic changes on mined dunes drive the composition of the dung beetle fauna toward convergence with that in natural dune forest on unmined dunes. We assessed the pattern of these changes using a 23‐year vegetational chronosequence on mined dunes, which passes from grassland (approximately 1 year) to open Acacia shrubland thicket to Acacia karroo‐dominated woodland (approximately 9 years). Across this sequence, which represents successional stages in the restoration of dune forest, there was a sequential trend toward convergence in dung beetle species composition in both the entire species complement and, particularly, in shade specialist species. However, species abundance patterns showed a trend toward convergence only in early chronosequence Acacia woodland, followed by a decline in similarity between dung beetle assemblages of older Acacia woodland and unmined natural forest. This trend toward divergence was common both to the entire species complement, which includes widespread taxa, and to species endemic to Maputaland or the east coast. These trends in similarity and dissimilarity between dung beetle assemblages closely parallel the greater physiognomic and microclimatic similarity between early Acacia woodland and natural forest and the relative dissimilarity of older Acacia woodland. In conclusion, although percentage similarities between dung beetle assemblages of approximately 12‐year woodland and natural forests were comparable with those between each natural forest stand, decline in similarity in older woodland stands suggests that lasting convergence in dung beetle species abundance will only be attained once the Acacia woodland is replaced by secondary natural forest.     

Impacts of Small‐scale Clearings due to Selective logging on Dung Beetle Communities

Conservation of biodiversity in production forests is crucial for mitigating biodiversity loss in the tropics. The major ecological impacts of selective logging are often the result of small clearings for skid trails, logging roads, log yards, and logging camps; however, their impacts on forest biodiversity have rarely been examined. The purpose of this study was to assess the impacts of these clearings on a forest‐dependent faunal group, dung beetles, and to identify the environmental factors responsible. Abundance and species richness of dung beetles decreased drastically in clearings, but directly increased in forests with the distance from roads/trails; abundance and species richness at 10 m from roads/trails were almost comparable with those detected in further interior forests. Similarly, species composition was significantly different between forests and clearings (except skid trails) but recovered within a short distance from roads/trails. Canopy openness was the most important environmental factor affecting the abundance, and species richness and composition of dung beetles; most dung beetle species were concentrated under closed forest canopy with less than 10 percent of canopy openness, whereas canopy openness ranged from 16 to 53 percent in clearings. Our study demonstrates that even small‐scale, unpaved clearings affect dung beetle communities through increased canopy openness. Although the effective distance was not very large, a considerable portion of logged areas can be affected when road networks are dense therefore minimizing the density of road networks and enhancing canopy recovery after logging are important for retaining biodiversity in tropical production forests.     

Generalist dung attraction response in a New Zealand dung beetle that evolved with an absence of mammalian herbivores

1. Dung beetles (Scarabaeidae: Scarabaeinae) are integral parts of many ecosystems because of their role in decomposition of dung; particularly mammal dung, which forms the diet of both larvae and adults. 2. New Zealand dung beetles are unusual as they are flightless and evolved on islands with a highly depauperate mammal fauna and thus without the usual dung resource used by dung beetles elsewhere. The diet of New Zealand dung beetles is unknown. 3. We hypothesised (1) that the endemic dung beetle Saphobius edwardsi would be attracted to a broad range of food types, and (2) that S. edwardsi would be able to survive and reproduce on a range of dung types and puriri (Vitex lucens) humus. 4. Laboratory choice tests identified that S. edwardsi was attracted to a range of mammal, bird, invertebrate, and reptile dung types, but not to non‐dung food sources. Five‐month no‐choice tests found that beetle survival rates were lower for beetles fed with humus compared with those fed on mammal, bird, or invertebrate dung. None of the beetles reproduced. 5. This study suggests S. edwardsi have a strong preference for dung, and are likely to be broad dung generalists in their feeding behaviour.     

Tropical rain forest fragmentation,howler monkeys (Alouatta palliata), and dung beetles at Los Tuxtlas,Mexico

In Neotropical rain forests, fresh mammal dung, especially that of howler monkeys, constitutes an important resource used by dung beetles as food and for oviposition and further feeding by their larvae. Tropical rain forest destruction, fragmentation, and subsequent isolation causing reductions in numbers of and the disappearance of howler moneys may result in decreasing numbers of dung beetles, but this has not been documented. In this study, we present information on the presence of howlers and dung beetles in 38 isolated forest fragments and 15 agricultural habitats. Howler monkeys were censused by visual means, while dung beetles were sampled with traps baited with a mixture of howler, cow, horse, and dog dung. Results indicated that loss of area and isolation of forest fragments result in significant decrements in howlers and dung beetles. However, dung beetle abundance was found to be closely related to the presence of howler monkeys at the sites and habitats investigated. Scenarios of land management designed to reduce isolation among forest fragments may help sustain populations of howler monkeys and dung beetles, which may have positive consequences for rain forest regeneration. Am. J. Primatol. 48:253–262, 1999. © 1999 Wiley‐Liss, Inc.     

Rapid Turnover and Edge Effects in Dung Beetle Assemblages (Scarabaeidae) at a Bolivian Neotropical Forest-Savanna Ecotone1

Habitat fragmentation and the widespread creation of habitat edges have recently stimulated interest in assessing the effects of ecotones on biodiversity. Ecotones, natural or anthropogenic, can greatly affect faunal movement, population dynamics, species interactions, and community structure. Few data exist, however, on insect community response to forest–savanna ecotones, a natural analog to anthropogenically cleared areas adjacent to forest. In this study, the abundance, total biomass, average individual biomass, and distribution of scarabaeine dung beetles were examined at a sharp tropical evergreen forest–savanna ecotone in Santa Cruz, Bolivia. The abundance, total biomass, and average individual biomass of dung beetles varied significantly across the forest, edge, and savanna habitats. Species richness (S_obs) also varied significantly across the three habitats, but statistical estimations of true species richness (S_est) did not. Habitat specificity of the dung beetles in this study was extremely high. Of the 50 most common species collected during the study, only 2 species were collected in both the forest and savanna habitats, signaling nearly complete community turnover in just a few meters. Strong edge effects were evidenced by the decline in abundance, total biomass, and species richness at the forest‐savanna boundary.     

Foraging Patterns of Sympatric Hornbills during the Nonbreeding Season in Arunachal Pradesh, Northeast India

The diet and food resource partitioning of three sympatric hornbills (Great Hornbill Buceros bicornis, Wreathed Hornbill Aceros undulatus, and Oriental Pied Hornbill Anthracoceros albirostris) during the nonbreeding season were studied relative to fruit availability in a foothill semievergreen forest of Arunachal Pradesh, northeast India. Hornbills fed on fruits of 49 plant species that comprised over 95 percent of their diet. Hornbill species partitioned food resources by varying the relative contribution of figs and non‐fig fruits in the diet. Similarity in non‐fig fruit diet was low. Ten species contributed to over 90 percent of the non‐fig diet. The availability of non‐fig fruits was much lower in the nonbreeding season than in the breeding season; however, despite lower fruit availability during the nonbreeding season, hornbills had a wide diet breadth and indirect evidence suggests that Wreathed Hornbills foraged widely in this season for fruit. Great Hornbills relied more on figs that were available year‐round. The diverse diet breadth that included rare and patchy fruit resources underscores the importance of conserving large forest tracts for hornbills.     

Dung beetles in continuous forest, forest fragments and in an agricultural mosaic habitat island at Los Tuxtlas, Mexico

With the aim of determining what kind of landscape mosaics might sustainmaximum diversity and minimum species loss, dung beetles were sampled withbaited pitfall traps to compare species richness and species composition in atract of continuous forest, forest fragments and a habitat island consisting ofa mosaic of forest and arboreal crops in Los Tuxtlas, southern Mexico. Wecaptured 7332 dung beetles representing 33 species. Similar numbers of specieswere captured in the three habitats. However, 56% of individuals were capturedin the continuous forest, 29% in the mosaic habitat and 15% in the forestfragments. Eight species (Canthon femoralis,Copris laeviceps, Canthidium centrale,Onthophagus batesi, Deltochilumpseudoparile, O. rhinolophus, Canthonviridis vazquezae and Dichotomius satanus) accounted for 90% of thecaptures, but their relative dominance varied among habitats. A clear trend wasevident in the number of dung beetles captured in the dung processing guilds(rollers/tunnelers) as well as in the diurnal and nocturnal guilds, withcaptures decreasing from the continuous forest to the mosaic habitat to theforest fragments. A similar trend was detected in detection rates for medium andsmall size dung producing mammals. Species richness of forest fragments andmosaic habitat did not differ from that found in the continuous forest, butthese habitats differ significantly in species richness from isolated shaded andunshaded plantations, linear strips of vegetation, the forest–pasture edge andpastures according to rarefaction analysis. The co-occurrence of the continuousforest, the mosaic habitat and the cluster of forest fragments in closeproximity seems to be preserving a diverse assemblage of dung beetle species inthe local landscape.     

Ancient forest fragmentation or recent radiation? Testing refugial speciation models in chameleons within an African biodiversity hotspot

Aim East Africa is one of the most biologically diverse regions, especially in terms of endemism and species richness. Hypotheses put forward to explain this high diversity invoke a role for forest refugia through: (1) accumulation of new species due to radiation within refugial habitats, or (2) retention of older palaeoendemic species in stable refugia. We tested these alternative hypotheses using data for a diverse genus of East African forest chameleons, Kinyongia. Location East Africa. Methods We constructed a dated phylogeny for Kinyongia using one nuclear and two mitochondrial markers. We identified areas of high phylogenetic diversity (PD) and evolutionary diversity (ED), and mapped ancestral areas to ascertain whether lineage diversification could best be explained by vicariance or dispersal. Results Vicariance best explains the present biogeographic patterns, with divergence between three major Kinyongia clades (Albertine Rift, southern Eastern Arc, northern Eastern Arc) in the early Miocene/Oligocene (> 20 Ma). Lineage diversification within these clades pre‐dates the Pliocene (> 6 Ma). These dates are much older than the Plio‐Pleistocene climatic shifts associated with cladogenesis in other East African taxa (e.g. birds), and instead point to a scenario whereby palaeoendemics are retained in refugia, rather than more recent radiations within refugia. Estimates of PD show that diversity was highest in the Uluguru, Nguru and East Usambara Mountains and several lineages (from Mount Kenya, South Pare and the Uluguru Mountains) stand out as being evolutionarily distinct as a result of isolation in forest refugia. PD was lower than expected by chance, suggesting that the phylogenetic signal is influenced by an unusually low number of extant lineages with long branch lengths, which is probably due to the retention of palaeoendemic lineages. Main conclusions The biogeographic patterns associated with Kinyongia are the result of long evolutionary histories in isolation. The phylogeny is dominated by ancient lineages whose origins date back to the early Miocene/Oligocene as a result of continental wide forest fragmentation and contraction due to long term climatic changes in Africa. The maintenance of palaeoendemic lineages in refugia has contributed substantially to the remarkably high biodiversity of East Africa.     

Evidence that sex‐specific signals may support mate finding and limit aggregation in the dung beetle Aphodius fossor

1. In temperate climates, dung is often colonised by several species of endocoprid (dwelling) dung beetles which use pats for feeding, shelter, and reproduction. 2. Endocoprid beetles aggregate even when offered patches (dung pats) of consistent age, size, and origin, suggesting that beetles themselves might influence the attractiveness of patches to members of their own species. Both pheromones, and physical changes to the structure of dung pats caused by colonising beetles have been suggested as mechanisms facilitating intraspecific aggregation, but neither of these hypotheses have been empirically tested. 3. Using a common European dung beetle (Aphodius fossor L.), we conducted a simple choice experiment designed to test whether (i) earlier colonisation by conspecifics could alter dung attractiveness and (ii) whether attraction was influenced by sex‐specific signals. 4. We found that female beetles are repelled by dung colonised by conspecific females and are attracted to dung colonised by conspecific males. Male beetles show no evidence of attraction or repellence for dung colonised by either sex. Neither in females nor males was uncolonised dung found to be significantly more or less attractive than predicted by non‐preference. 5. Our results suggest that for A. fossor male‐produced signals may support mate finding in patchy environments, and that female‐produced signals may serve to discourage subsequent colonisation by additional females.     

Do riparian reserves support dung beetle biodiversity and ecosystem services in oil palm-dominated tropical landscapes?

Agricultural expansion and intensification are major threats to global biodiversity, ecological functions, and ecosystem services. The rapid expansion of oil palm in forested tropical landscapes is of particular concern given their high biodiversity. Identifying management approaches that maintain native species and associated ecological processes within oil palm plantations is therefore a priority. Riparian reserves are strips of forest retained alongside rivers in cultivated areas, primarily for their positive hydrological impact. However, they can also support a range of forest‐dependent species or ecosystem services. We surveyed communities of dung beetles and measured dung removal activity in an oil palm‐dominated landscape in Sabah, Malaysian Borneo. The species richness, diversity, and functional group richness of dung beetles in riparian reserves were significantly higher than in oil palm, but lower than in adjacent logged forests. The community composition of the riparian reserves was more similar to logged forest than oil palm. Despite the pronounced differences in biodiversity, we did not find significant differences in dung removal rates among land uses. We also found no evidence that riparian reserves enhance dung removal rates within surrounding oil palm. These results contrast previous studies showing positive relationships between dung beetle species richness and dung removal in tropical forests. We found weak but significant positive relationships between riparian reserve width and dung beetle diversity, and between reserve vegetation complexity and dung beetle abundance, suggesting that these features may increase the conservation value of riparian reserves. Synthesis and applications: The similarity between riparian reserves and logged forest demonstrates that retaining riparian reserves increases biodiversity within oil palm landscapes. However, the lack of correlation between dung beetle community characteristics and dung removal highlights the need for further research into spatial variation in biodiversity–ecosystem function relationships and how the results of such studies are affected by methodological choices.