Abundance Of Mounds Research Articles

Utilization of IGN historical aerial photographs and Google earth for measuring changes in land use and evolution of termite lenticular mound abundance in paddy fields in Cambodia

AbstractThis study was conducted to investigate termite mounds' dynamics in paddy fields in Cambodia. Historical aerial images collected in the 50s by the French Institut Géographique National (IGN) and recent Google Earth (GE) were analysed to study land use changes and mound distribution in 30 plots. A significant decrease in the surface covered by scrublands and forests was measured (from 37% in 1953 to less than 2% in 2021). We observed that most mounds seen in the field in 2021 could also be seen in IGN and GE images (88.6%), indicating that mounds have a long lifespan but also that they can be built in less than 70 years. Mound density was neither influenced by the topography nor by the restructuring of the paddy field boundaries during the Khmer Rouge regime. However, areas that were more recently converted into paddy fields had more mounds compared to areas that were already paddy fields in 1953 (2.92 vs. 1.53 mounds ha−1, respectively). Therefore, deforestation and other environmental changes have turned mounds into remnants of the forests that had almost completely disappeared. This highlights the importance of protecting these specific environments in a changing world facing a major crisis of biodiversity loss.

Mound abundance, the livelihood impacts and determinant factors of termites in Meta Robi district, central Ethiopia

This study aimed to assess mound abundance, the livelihood impacts of termites, and determinant factors in the Meta Robi District, Ethiopia. A descriptive research design was used for primary data collection from the three selected kebeles. Termite nests were counted from each Goxi (the sub-kebele and the smallest unit in Ethiopia) using a transect line. In addition, 190 household heads were selected randomly from each kebele, and a questionnaire survey was used to collect primary data from the respondents. Termite nests were abundant in Warabo (7.25.71 per 1000 m2), but scarce in Warke Walensu Kebele (2.25.50 per 1000 m2). Teff (49.5%) and wheat (32.6%) were the most severely affected crops by termites. The mean annual hectare of land and quintals of teff and wheat damaged per household was higher in Warabo Kebele (p < 0.05). The annual economic loss from termites in crops was higher in Warabo (4722.23 ± 869.67 ETB and 4396.43 ± 852.65 ETB from teff and wheat per household, respectively). Agroecology, deforestation, overgrazing, and crop types were the factors that determined termite abundance and its impact on farmers' livelihoods. Mound opening and smoking are the management methods currently used, but no government support exists. Therefore, integrated and effective termite pest management is critical for long-term food security in the study area.

Suitability of containerized toxicant to control Solenopsis invicta (Hymenoptera: Formicidae) threatening cave species in Bexar County, Texas.

Several protected troglobitic invertebrate species are known to occur in caves on Joint Base San Antonio-Camp Bullis, Bexar County, Texas, United States. The United States Fish and Wildlife Service (USFWS) identified red-imported fire ant Solenopsis invicta (hereafter RIFA) (Buren 1972) as the primary threat to cave species' nutrient sources, cave crickets, Ceuthophilus secretus (Scudder 1894). Per the service's recommendations, Joint Base San Antonio-Camp Bullis currently implements boiling water mound injections with digging for RIFA control. However, treatment effectiveness is highly variable and largely dependent on the time of day, weather, and personnel diligence. Toxicants have been used for RIFA treatment throughout the world, but concerns exist that traditional applications of toxicant bait around caves might be accessible and inadvertently affect nontarget arthropods, including cricket populations. To mitigate this accessibility, physically limiting access to the toxicant from crickets may be an option. Our objectives were to (i) compare and evaluate the effectiveness of Amdro (Hydramethylnon) and Advion (Indoxacarb) granular baits housed in Ants-No-More Bait Stations (Kness MFG. Inc., Albia, IA) and (ii) evaluate the distance of effectiveness of each bait within a bait station. Ultimately, we observed a 98% reduction in RIFA mound abundance from both baits. Additionally, RIFA mounds within 10 m of the containerized toxicant were reduced by 70%. Our pilot study suggested that Ants-No-More Bait Stations are an effective way to reduce RIFA mounds by 70% if placed 10 m from each other. In practice, this could include bait stations completely covering a particular distance to a cave entrance or fewer bait stations in a ring barrier at a single radial distance to a cave entrance. Containerized toxicants may be a cost-effective and safe RIFA control option around protected cave environments, but further studies are needed to determine potential effects on nontarget arthropods, optimal bait station configuration, and potential effects of biomagnification.

Abundance, perceptions and utilizations of termite mounds in Cambodia

AbstractIn the Lower Mekong Basin, paddy fields often appear as mosaics, with soil mounds covered by trees or other plants in a spotty distribution. These soil mounds are commonly named termite ‘lenticular mounds’ because termite bioturbation is considered to be at their origin. Termite mounds host a large diversity of animals and plants, increasing landscape patchiness. Because the preservation of these islands of biodiversity is threatened by modern agricultural practices, the aim of this study was to quantify their abundance and the services they provide to the local population. The abundance of mounds and their use by the population were quantified in a catchment in Cambodia. We found that mounds density reached ~2 mounds ha−1. Interviews carried out within the catchment showed that most of the interviewees used mounds for increasing the fertility of their field and for the cultivation of rice and other plants (e.g. sponge gourd and pumpkin). In addition to their potential to increase plant productivity, the survey revealed that animals (rats and snakes), mushrooms and 13 plant species found on or in mounds were consumed by the population. In addition to potentially contributing to an increase in food diversity, mounds also impacted farmers' health by allowing access to 20 medicinal plant species and indirectly via a reduction in pesticide use. In conclusion, this study is the first attempt to quantify the large number of services provided by termite mounds in Cambodia. This increase in the knowledge of the diversity of environmental and socioeconomic services provided by termite mounds is likely to contribute to their preservation and provide a basis for the sustainable management of biodiversity in paddy fields in the Lower Mekong Basin region.

Red Imported Fire Ant, Solenopsis invicta (Burden) (Hymenoptera: Formicidae), Abundance and Arthropod Community Diversity Affected by Pasture Management

The red imported fire ant, Solenopsis invicta (Buren) (Hymenoptera: Formicidae), is one of the most prolific invasive species in the southeastern US. These invaders preferentially colonize highly disturbed land and grassland habitat. Management of livestock in pasture systems can have a profound impact on the level of disturbance in grassland habitats, and we hypothesized that adaptive multi-paddock pasture management would significantly increase S. invicta abundance in southeastern US pastures where arthropod diversity would decrease as S. invicta abundance increases. We studied the effects that adaptive multi-paddock pasture management systems (based on stocking density, rotation frequency, and insecticide/anthelmintic [wormer] application rates) have on fire ant mound abundance and arthropod diversity for the soil, foliar, and dung communities. Solenopsis invicta mounds and mound areas were documented along transect lines in 6 pastures. Soil and foliar arthropod communities were collected along the same transect lines, and dung communities were sampled from pats within the pasture system. Pastures managed under adaptive multi-paddock practices had 3.4× more S. invicta mounds and 4.6× more mound area than their conventionally managed counterparts. However, arthropod diversity did not correlate with S. invicta abundance in any of the 3 arthropod communities sampled. This study shows adaptive multi-paddock pasture management can increase S. invicta mound abundance, but arthropod communities in adaptive multi-paddock pastures do not suffer decreased diversity from increased abundance of S. invicta.

The Potential of Termite Mound Spreading for Soil Fertility Management under Low Input Subsistence Agriculture

Termites can play a localized prominent role in soil nutrient availability and cycling because mound materials are often enriched in nutrients relative to surrounding soil. Mound materials may thus prove to be useful amendments, though evidently mound spatial arrangement needs to be considered as well. Furthermore, it is not known if gradients of soil properties exist from termite mound to interspace sites. Studying both aspects would be required to decide whether spreading of mounds or spatially differentiated management of surrounding crop to accommodate soil fertility gradients would be valid nutrient-management strategies. Mound abundance and mass were estimated at 9 and 4 mounds ha−1, representing 38.9 and 6.3 t ha−1 on Nitisols and Vertisols, respectively. Soil physical and chemical properties were measured on samples collected from internal and external parts of mounds and adjacent soils at 0.5, 1 and 10 m away from mounds. In general, termite mounds were enriched in plant nutrients and SOC on Vertisols but not on Nitisols. Termite mounds constituted only 0.3 to 1.3% of the 0–15 cm SOM stock on a per ha basis but nevertheless the immediate vicinity of termite mounds was a relative fertile hotspot. Hence, under the studied condition, we suggest spatial arrangement of crop around termite mounds according to soil fertility gradient and spatially differentiated nutrient management strategies. Our result suggests recommendation of termite mound spreading for soil nutrient amendment has to consider plant nutrient stock in termite mounds on per ha basis besides their nutrient enrichment. Interesting topics for future investigation would be growth experiment for different crops with mound materials treatment. It would also be interesting to study the effect mound building termite on soil properties under different soil conditions, slope class and land use.

Termite mound cover and abundance respond to herbivore-mediated biotic changes in a Kenyan savanna.

Both termites and large mammalian herbivores (LMH) are savanna ecosystem engineers that have profound impacts on ecosystem structure and function. Both of these savanna engineers modulate many common and shared dietary resources such as woody and herbaceous plant biomass, yet few studies have addressed how they impact one another. In particular, it is unclear how herbivores may influence the abundance of long‐lived termite mounds via changes in termite dietary resources such as woody and herbaceous biomass. While it has long been assumed that abundance and areal cover of termite mounds in the landscape remain relatively stable, most data are observational, and few experiments have tested how termite mound patterns may respond to biotic factors such as changes in large herbivore communities. Here, we use a broad tree density gradient and two landscape‐scale experimental manipulations—the first a multi‐guild large herbivore exclosure experiment (20 years after establishment) and the second a tree removal experiment (8 years after establishment)—to demonstrate that patterns in Odontotermes termite mound abundance and cover are unexpectedly dynamic. Termite mound abundance, but areal cover not significantly, is positively associated with experimentally controlled presence of cattle, but not wild mesoherbivores (15–1,000 kg) or megaherbivores (elephants and giraffes). Herbaceous productivity and tree density, termite dietary resources that are significantly affected by different LMH treatments, are both positive predictors of termite mound abundance. Experimental reductions of tree densities are associated with lower abundances of termite mounds. These results reveal a richly interacting web of relationships among multiple savanna ecosystem engineers and suggest that termite mound abundance and areal cover are intimately tied to herbivore‐driven resource availability.

A facilitation between large herbivores and ants accelerates litter decomposition by modifying soil microenvironmental conditions

AbstractLarge herbivores and insects commonly coexist and play important functional roles in grassland ecosystems. The interactive effects of these two animal groups in shaping ecosystem processes and functioning are poorly understood. In a semi‐arid grassland of northeastern China, we previously found a reciprocal facilitation between large herbivores (cattle;Bos tarurs) and ants: cattle grazing led to a twofold increase in ant mound abundance compared with ungrazed sites, while the presence of ant mounds, in turn, increased the foraging of cattle during the peak of the growing season.Here, by using a large‐scale, 4‐year (2010–2013) manipulative experiment, we further investigated how such a facilitation between large herbivores and ants can affect a key ecosystem process, litter decomposition. Using a set of small‐scale reciprocal translocation litterbag experiments, we separated the effects of litter quality and soil microenvironmental factors altered by cattle and ants on litter decomposition rates.A significant interaction between the experimental factors, cattle grazing and ant presence, showed that litter decomposition rate was at the highest levels when both cattle and ants were present, with only a small impact when each was present on its own. Mechanistically, cattle and ants exerted limited effects on litter quality (litter C:N ratio). However, these animals greatly altered soil microenvironments by increasing soil N availability, which in turn increased soil microbial biomass and accelerated decomposition process.Synthesis. Our results demonstrate how positive interactions between two groups of animals, large herbivores and ants, can affect decomposition rates, with important consequences for ecosystem carbon and nutrient cycling. Large herbivores, either domestic or wild, often coexist and interact frequently with a diverse of other fauna in terrestrial ecosystems. Assessing their interactive effects will help us to better understand their role in shaping ecosystem processes and functioning with important management implications.A freePlain Language Summarycan be found within the Supporting Information of this article.

Abundance, population density and spatial ecology of mound-building termites in moist tropical deciduous forests of northern India

ABSTRACT Mound-building termites are ecosystem engineers whose abundance and spatial ecology are not adequately addressed in many forest ecosystems. We studied Odontotermes obesus mounds at two moist tropical deciduous forests (pure Sal and Sal-Teak mixed) in the Doon valley, northern India. Mound abundance, spatial pattern and termite population density were determined by direct count, nearest neighbour analyses and destructive sampling, respectively. Relations between mound attributes and stand characteristics such as woody vegetation diversity, density and tree stumps (representing food quality, quantity, open-space availability and disturbance) were tested at fine spatial scale using regression analyses. Active mounds were more abundant in the pure Sal stand (~8.0 mounds/ha) than in the mixed stand (~5.0 mounds/ha). Mean population density (both sites combined) was 2.01 × 105 individuals per mound. Population density was strongly correlated with mound volume. Predominance of young colonies was indicated by high occurrence (≥ = 65%) of small mounds (< 1.25 m3). Mounds were predominantly randomly distributed. However, the pure Sal stand showed a partial tendency towards aggregation. Our results revealed that woody species richness is an important, site-specific regulatory factor. Local-scale variations should be cautiously considered while up-scaling the contribution of O. obesus mounds to various ecosystem processes.

Distribution of the Red Imported Fire Ant Solenopsis invicta (Hymenoptera: Formicidae) in Central Florida Pastures.

Habitat disturbance has been found to facilitate the introduction of a wide range of species, including the red imported fire ant Solenopsis invicta Buren (Hymenoptera: Formicidae: Myrmicinae). Despite the link between S. invicta colonization and disturbance, little is known about how different intensities or types of disturbance might impact S. invicta populations. In this study, we used S. invicta populations in cattle pastures to understand how variation in disturbance type and frequency correlates with the density of S. invicta mounds. In total, 56 plots were surveyed for mound abundance during both the wet and dry seasons on a subtropical south Florida ranch. Explanatory variables were grouped into five categories based on disturbance type: 1) historic pasture conversion; 2) modern pasture management (mowing, dragging, chopping, or aerating); 3) grazing intensity (a measure vegetation height and dung pat abundance); 4) distance to human-made and natural localized disturbance (roads, ditches, and wetlands); and 5) abiotic conditions (soil temperature, soil moisture). Overall, the average number of mounds per plot was not significantly different between seasons, but was significantly higher in intensive pastures, which are converted to nonnative forage grasses than in seminative pastures during the dry season. Time since soil disturbance (aeration and chopping of pasture) was a significant predictor of S. invicta densities in both dry and wet seasons, with an increase in time since disturbance being associated with higher mound densities. Other forms of pasture management that did not disturb the soil, such as dragging and mowing, as well as distance to localized disturbances (wetlands, roads, and ditches) were not found to have a significant correlation in either season.

Reciprocal facilitation between large herbivores and ants in a semi-arid grassland

While positive interactions have been well documented in plant and sessile benthic marine communities, their role in structuring mobile animal communities and underlying mechanisms has been less explored. Using field removal experiments, we demonstrated that a large vertebrate herbivore (cattle; Bos tarurs) and a much smaller invertebrate (ants; Lasius spp.), the two dominant animal taxa in a semi-arid grassland in Northeast China, facilitate each other. Cattle grazing led to higher ant mound abundance compared with ungrazed sites, while the presence of ant mounds increased the foraging of cattle during the peak of the growing season. Mechanistically, these reciprocal positive effects were driven by habitat amelioration and resource (food) enhancement by cattle and ants (respectively). Cattle facilitated ants, probably by decreasing plant litter accumulation by herbivory and trampling, allowing more light to reach the soil surface leading to microclimatic conditions that favour ants. Ants facilitated cattle probably by increasing soil nutrients via bioturbation, increasing food (plant) biomass and quality (nitrogen content) for cattle. Our study demonstrates reciprocal facilitative interactions between two animal species from phylogenetically very distant taxa. Such reciprocal positive interactions may be more common in animal communities than so far assumed, and they should receive more attention to improve our understanding of species coexistence and animal community assembly.

AN INVERTEBRATE ECOSYSTEM ENGINEER UNDER THE UMBRELLA OF SAGE-GROUSE CONSERVATION.

Conservation practitioners often rely on areas designed to protect species of greatest conservation priority to also conserve co-occurring species (i.e., the umbrella species concept). The extent to which vertebrate species may serve as suitable umbrellas for invertebrate species, however, has rarely been explored. Sage-grouse (Centrocercus spp.) have high conservation priority throughout much of the rangelands of western North America and are considered an umbrella species through which the conservation of entire rangeland ecosystems can be accomplished. Harvester ants are ecosystem engineers and play important roles in the maintenance and function of rangeland ecosystems. We compared indices of the abundance of western harvester ants (Pogonomyrmex occidentalis) and Greater Sage-Grouse (Centrocercus urophasianus) at 72 sites in central Wyoming, USA in 2012. The abundance of harvester ant mounds was best predicted by a regression model that included a combination of local habitat characteristics and the abundance of sage-grouse. When controlling for habitat-related factors, areas with higher abundances of sage-grouse pellets (an index of sage-grouse abundance and/or habitat use) had higher abundances of ant mounds than areas with lower abundances of sage-grouse pellets. The causal mechanism underlying this positive relationship between sage-grouse and ant mound abundance at the fine scale could be indirect (e.g., both species prefer similar environmental conditions) or direct (e.g., sage-grouse prefer areas with a high abundance of ant mounds because ants are an important prey item during certain life stages). We observed no relationship between a broad-scale index of breeding sage-grouse density and the abundance of ant mounds. We suspect that consideration of the non-breeding habitat of sage-grouse and finer-scale measures of sage-grouse abundance are critical to the utility of sage-grouse as an umbrella species for the conservation of harvester ants and their important role in rangeland ecosystems.

Rainfall and soil properties influence termite mound abundance and height: A case study with Odontotermes obesus (Macrotermitinae) mounds in the Indian Western Ghats forests

Several fungus-growing termite species build mounds, or termitaria, that are conspicuous features of African and Asian landscapes. Studies of the genus Macrotermes in Africa have established that their mounds provide an environment buffered against extremes of temperature and humidity, as well as protection from predators, and are correspondingly modified in composition. However, no studies are available in the specific context of the Asian continent where termite mounds are also abundant. Hence this study focused on the abundance and properties of mounds built by Odontotermes obesus in relation to rainfall and parent soil properties in southern Indian forests, in the Western Ghats area. Termite mound densities and sizes were measured in 18 forests along a rainfall gradient from 1160 to 3670mmyr−1. The C and clay contents were analyzed in soil samples collected from mounds and the surrounding topsoil. Mound numerical density was positively correlated with mound height and rainfall had a negative relationship with the abundance. Neither vegetation type nor or rainfall influenced the clay content in the mound walls but a positive linear relation was observed between the clay content in the termite mound wall and that in the surrounding topsoil environment, suggesting a rather low impact of termites on the clay content in the mound soil. The C content in mound walls depended mainly on how much clay the termites used. In conclusion, this study shows that the amount of rainfall affects the abundance of O. obesus mounds in India while the amount of clay in the surrounding topsoil determines mound soil properties.

Abundance and Impact on Soil Properties of Cathedral and Lenticular Termite Mounds in Southern Indian Woodlands

Despite the acknowledged roles of termites in tropical ecosystems, the majority of published studies of epigeal mounds still address the African fauna and are principally concerned with spatial patterns and putative inter-colony competition, rather than the links between parent soil properties and mound establishment. Further, information about the effects of habitat disturbance, and especially fragmentation, is lacking. This study assessed the abundance and distribution of the cathedral- and lenticular-type aboveground mounds of fungus-growing termites (Macrotermitinae), which are a common feature of South Indian woodlands, in relation to soil properties (vertisol vs. ferralsol) and habitat fragmentation (forest vs. highway margins). Mound abundance averaged 3.5 (standard error, SE 0.8) ha(-1) (cathedral) and 12.9 (SE 2.1) ha(-1) (lenticular), but was not influenced either by soil properties or disturbance. However, the volume of soil stored in the mounds varied between 27 (SE 8) m(3) ha(-1) (ferralsol) and 47 (SE 6) m(3) ha(-1) (vertisol). At the watershed scale, such volumes are equivalent to a 3.1-mm layer of soil if spread evenly across the landscape, roughly the same as the estimated erosion over the life of a typical mound. Significantly more nutrients were stored in lenticular mounds, especially on the vertisol, but the significance of these at the ecosystem level was considered small. In conclusion, this study suggests that termite mounds, and especially lenticular mounds, have a significant impact on soil dynamics at the watershed scale but a limited impact on the distribution of C and nutrients.

Historical land use and present-day canopy thinning differentially affect the distribution and abundance of invasive and native ant species

Disturbance may play a key role in affecting animal invasions; less appreciated is that past and present disturbances might interact to affect invasion. For example, although large portions of forest ecosystems worldwide are jointly affected by a history of past agricultural land use as well as contemporary timber harvest, it is unclear whether these disturbances facilitate biological invasions. We conducted a large-scale experiment that coupled adjacent non-agricultural and post-agricultural sites and a factorial canopy-thinning manipulation to understand how past agricultural land use might interact with contemporary canopy thinning to affect the distribution (i.e., presence/absence of mounds) and abundance of a highly invasive ant species, Solenopsisinvicta, and common native ant species, Dorymyrmexbureni. Mounds of S. invicta were more likely to be present in unthinned post-agricultural habitats than unthinned non-agricultural habitats, but this legacy effect disappeared with canopy thinning. In unthinned habitats, the presence of D. bureni mounds did not differ based on past land use. However, presence of D. bureni mounds was greater in thinned non-agricultural habitats than thinned post-agricultural habitats. Once present in an area, mound abundance was largely related to temperature near the ground for both species, and negatively related to soil compaction for D. bureni. Our results provide large-scale evidence that an understanding of anthropogenic events that occur decades before present may be essential for interpreting contemporary invasion dynamics and the distribution of some species, and that local contemporary habitat characteristics play a key role in determining ant abundance once an area is colonized.

A case study of termite mound occurrence in relation to forest edges and canopy cover within the Barandabhar forest corridor in Nepal

The Barandabhar forest corridor (BFC) in the Royal Chitwan National Park is an example of a buffer zone implemented to mitigate the effect of local communities on conservation and the effect of conservation on local communities. However, the effectiveness of these actions for conservation may depend on the intensity of human activity and the species considered. We conducted a field survey within the BFC to study how termite mound occurrences relate to forest edges, human activity and canopy cover, and to examine the spatial patterns of the edge effect in terms of dead wood availability, logging and canopy cover. The results show that termite mound abundance was significantly affected by edge effects such that the abundance increased from ~5 mounds/ha along the edge to ~14mounds/ha in the core areas 2 km inside the forest. The forest edge was partly defined by decreased canopy cover and increased signs of logging. Our results suggest that buffer zone practices may be a valid method to mitigate edge effects on termites in core areas. However, we also found indications of human activities effecting canopy cover that could influence the effectiveness of buffer zone management in this area. Key words: Chitwan, isoptera, spatial distribution, dead wood, gap dynamic, disturbance, microclimate, buffer zone, edge effect.

Quantifying the masses of Macrotermes subhyalinus mounds and evaluating their use as a soil amendment

Maintenance of soil quality is critical to environmental sustainability. However, its input cost is becoming unaffordable to small scale farming communities in Africa. Termites are an important element in traditional land-management practices in the Sahel. In their role as regulators of soil ecosystem processes, termites perform a number of vital functions. Although the application of termite mound materials as available nutrient sources is a common practice on the African continent, little is known about the density of masses of mounds and the amounts of nutrients they contain. First, two representative sites of 2km×1km were delineated and then termite mound abundance was recorded (43 and 30 in the two sites). They were used for volume and mass determinations. The study revealed an average abundance of 10moundsha−1 on Calcisols and 14moundsha−1 on Luvisols, with estimated mound soil masses of 13.5tha−1 and 58.9tha−1, respectively. Because termite mounds contain many pores and void spaces, a regression equation that can estimate the correct termite mound mass from mound volume and mound wall bulk density was developed. This revealed that conventional calculations of mound mass without correction for the voids overestimate the true mass by over 10%. Soil samples were collected from top and bottom parts of 6 selected mounds and in the different horizons of adjacent undisturbed soil profiles. Although insignificant differences in organic carbon and total nitrogen contents between the termite mound materials and the surface horizons of the adjacent soils were found, the termite mounds constitute a store of 27–53kgha−1 of total N and 186.3–306kgha−1 of OC. On both sites, the available P and the exchangeable Mg and K contents of termite mound soil were significantly higher than adjacent soils by 90%, 36% and 188%, respectively. Termite mounds contain a considerable store of plant nutrients and the use of mound material as a soil amendment shows great potential for improving soil chemical fertility.

Effects of controlled livestock grazing and annual prescribed fire on epigeal termite mounds in a savannah woodland in Burkina Faso

The diversity and abundance of epigeal termite mounds were investigated in response to controlled livestock grazing and annual prescribed fire in a Sudanian savannah-woodland in Tiogo State Forest. Sampling of termite mounds was carried out in 4×4 subplots of 0.25 ha in a split-plot experimental design during the rainy season in 2002. There were two main plots of which one was fenced to exclude livestock grazing and the second exposed to grazing. Each of the main plots included 4 subplots with annual prescribed fire since 1992 and 4 subplots without fire. Data were collected on the number and characteristics of termite mounds. A mean density of 698 mounds ha−1 was recorded. Mounds built by Trinervitermes spp. were the most abundant followed by Cubitermes spp., Macrotermes subhyalinus and M. bellicosus. The large mound-builders Macrotermes spp. dominated the community interms of basal area (96% of the total) and above-ground volume (99%). The diversity of mound types was notaffected by livestock grazing and annual early prescribed fire (P>0.05). There was no statistical effect of livestock grazing on mound density, whereas a strong depressive effect of annual fire was observed for Trinervitermes spp. mound density (P=0.012). In this ecosystem, annual prescribed fire appeared to be the major determinant for termite mound abundance.

Subsistence Technology of Nigerian Chimpanzees

A trademark of Homo sapiens is the enormous variation in behavioral patterns across populations. Insight into the development of human cultures can be aided by studies on communities of Pan across Africa that display unique combinations of social behavior and elementary technology. Only cross-population comparisons can reveal whether the diversity reflects differential genetics, environmental constraints, or is a cultural variant. However, the recently recognized and most endangered subspecies, Pan troglodytes vellerosus, remains completely unstudied in this respect. We report first evidence from a new long-term study of Nigerian chimpanzees at Gashaka. Their dietary composition is highly varied and they have to cope with high concentrations of antifeedant defenses of plants against consumption. Gashaka chimpanzees use a varied tool kit for extractive foraging. For example, they harvest insects throughout the year, via digging sticks and probes, to obtain honey from stingless-bee and honeybee nests, dipping wands to prey on army ants, and fishing rods to eat arboreal ants. Tools appeared to be custom-made with a considerable degree of standardization in length, diameter, and preferential use of distal ends. Moreover, compared to the rainy season, tools were longer during the dry season when insects retreat further into their nests. Many of the expressions of subsistence technology seem to be environmentally constrained. Most notably, the absence of termite-eating could reflect a low abundance of mounds. Other traits may represent cultural variation. For example, the chimpanzees did not hammer open 2 types of hard-shelled nuts with tools, unlike what occurs elsewhere in West Africa. The prevalence of elementary technology may indicate that the material culture of Gashaka chimpanzees is most related to core cultural tendencies of Central African populations.

Efficacy of Broadcast and Perimeter Applications of S-Methoprene Bait on the Red Imported Fire Ant in Grazed Pastures

The red imported fire ant, Solenopsis invicta (Buren), is a major pest in the United States because of its painful sting. Toxic bait has been an important management tool against fire ants, but site registrations prohibit applications of most baits on grazed pastures. Extinguish, containing the insect growth regulator methoprene, was selected for this study because it has a broad site registration that includes grazed pastures. The primary objective of this research was to evaluate the efficacy for control of red imported fire ants by using broadcast applications of methoprene bait at a label rate of 1,121 g/ha versus applications around the perimeter of a target area at the reduced rate of 280 g/ha. Grazed pastures in Lee County, Alabama, and Chambers County, Alabama, were selected for this study, with broadcast treatments, perimeter treatments, and controls replicated three times at each site. All mounds were counted and rated using the USDA population index before applications and then at 8 and 16 wk posttreatment. Perimeter applications did not significantly reduce S. invicta mound abundance, but bait treatments significantly reduced mound abundance at 16 wk posttreatment at site 1 where applications were conducted in early evening. However, broadcast applications were not effective at site 2 where treatments were conducted in early morning with warmer temperatures. Emergence of winged alates was observed at 12 wk posttreatment, followed by a high density of incipient mounds that may have masked the full treatment effect of methoprene applications at site 2. Methoprene bait was effective in reducing abundance of S. invicta only when full label rates were applied.