The aardwolf (Proteles cristatm Sparrman) 1783 as predator of termites*

(1) Food selection of aardwolves was studied by a comparison of faecal contents with available termite populations. Observations are reported on the foraging behaviour, and on aspects of termite biology which expose various species to predation. (2) The aardwolf diet shows a very high selectivity for one species of termite, Trinervitermes bettonianus in the Serengeti and ecologically similar species elsewhere. (3) Both morphology and foraging behaviour are very well adapted to feeding on Trinervitermes bettonianus or similarly behaving termites. The aardwolf does not dig for food; hearing is probably an important sense used for locating prey. (4) Various aspects of the termites' protection against aardwolf predation are discussed. (5) The aardwolf diet shows an increase in variety during the rains; the cause of this is discussed. (6) Some brief notes are made about territorial behaviour, scent marking and the use of middens. (7) As a management recommendation regular grassland burning is suggested for areas where the presence of aardwolves is considered desirable.     

A model of litter harvesting by the Western Australian wheatbelt termite,Drepanotermes tamminensis (Hill), with particular reference to nutrient dynamics

A series of papers have been published which describe the influence of vegetation and soil type on the Western Australian wheatbelt termite,Drepanotermes tamminensis (Hill), and also on its litter harvesting levels and contribution to the soil nutrient budget. This paper integrates these findings by means of a computer simulation model. The model consists of three modules which respectively describe the dynamics of litter on the ground, the dynamics of litter within termite mounds and how these in turn influence nutrient loads within the habitat. The outputs of the model suggest that this litter harvesting termite plays an important role in the nutrient dynamics of the area and it provides an estimate of the unmeasured variable, litter consumed in mounds by termites, which is consistent with measurements for other termite species with similar feeding habits.     

Effects of nutrients on feeding activities of the pest termite Heterotermes tenuis (Isoptera: Rhinotermitidae)

Heterotermes tenuis is a native termite of large negative impact on the Brazilian economy. Many studies have focused on optimizing the baiting method for termite control by improving its use and its efficacy. In order to maximize termite bait consumption, this study aimed to select nutrient solutions which are able to enhance termite feeding. The effects of some sugars and urea on feeding preference of the subterranean termite H. tenuis were determined by double choice feeding tests, and the consumption was evaluated by variation in dry mass of filter paper after 28 days of termite feeding. Most of the solutions tested did not significantly influence feeding of H. tenuis . Termites fed preferentially on filter paper treated with 0.03 g/ml trehalose and 0.015 g/ml urea solutions. The data indicate that trehalose and urea solutions are phagostimulants to H. tenuis , and their future use in bait matrices may increase consumption of baits and improve this control technique.     

桉树幼林白蚁的危害、种类及区系分布特点的研究

对白蚁危害桉树幼林进行系统观察,得知白蚁危害桉树幼林的根部,而导致植株枯死类型分为三类,另尚有少部分植株是由于白蚁啃食树干 处树皮而在旱季枯死。蚁害多发生在桉树定植至山场的头4－6个月内,定植1年以后的桉树则很少因白蚁危害而死亡。同时,对桉树幼林的白蚁种类进行全面的普查,结果发现在三明危害桉树的白蚁种类有5种,它们是家白蚁、黑翅土白蚁、黄胸散白蚁、闽华歪白蚁、海南大白蚁,其中后三种为国内首次报道危害桉树,黑翅土白蚁为桉树白蚁的优势种。     

Parallel evolution of termite‐egg mimicry by sclerotium‐forming fungi in distant termite groups

Among the great diversity of insect–fungus associations, fungal mimicry of termite eggs is a particularly fascinating consequence of evolution. Along with their eggs, Reticulitermes termites often harbour sclerotia of the fungus Fibularhizoctonia sp., called ‘termite balls’, giving the fungus competitor‐free habitat within termite nests. The fungus has evolved sophisticated morphological and chemical camouflage to mimic termite eggs. To date, this striking insect–fungus association has been found in eight temperate termite species, but is restricted to the lower termite genera Reticulitermes and Coptotermes. Here, we report the discovery of a novel type of termite ball (‘Z‐type’) in the subtropical termite, Nasutitermes takasagoensis. Phylogenetic analysis indicated that the Z‐type termite ball is an undescribed Trechisporoid fungus, Trechispora sp., that is phylogenetically distant from Fibularhizoctonia, indicating two independent origins of termite‐egg mimicry in sclerotium‐forming fungi. Egg protection bioassays using dummy eggs revealed that Reticulitermes speratus and N. takasagoensis differ in egg‐size preference. A comparative study of termite ball size and egg‐size preference of host termites showed that both fungi evolved a termite ball size that optimized the acceptance of termite balls as a unit investment. Termite‐egg mimicry by these fungi offers a model case of parallel evolution. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 531–537.     

Spatial and temporal hotspots of termite‐driven decomposition in the Serengeti

Ecosystem engineers are organisms that directly or indirectly control the availability of resources to other organisms by causing physical state changes in biotic or abiotic materials. Termites (Insecta, Isoptera) are among the most important ecosystem engineers in tropical ecosystems. We used a field experiment in the tall grasslands of Serengeti National Park, Tanzania, to investigate 1) the consumption by termites of grass litter and dung baits along the landscape gradient of catena position, and 2) seasonal variation in litter and dung removal. Our maps of termitaria and patterns of bait removal revealed clear spatial and temporal hotspots of termite activity. In the dry season termites removed more baits at the top‐catena positions than at the bottom positions, but there was no effect of catena position in the wet season. Spatial hotspots of termite activity overlapped with those of both mammalian herbivores and predators. Within the framework of ecosystem engineering, this study suggests that intraspecific aspects of spatial heterogeneity and temporal variability deserve much greater consideration.     

Root foraging strategies and soil patchiness in a humid savanna

In Lamto (Côte d'Ivoire), the savanna is a patchy environment as far as soil is concerned: tree clumps and termite mounds lead to higher nutrient contents than in the surrounding savanna. Mature Borassus aethiopum (Mart.) specimens are tall palm trees dominating the community, with aerial parts located out of these nutrient-rich patches.Palm root densities were compared under tree clumps and in the surrounding savanna, and were also sampled along transects between palm trees and nutrient-rich patches (two clumps and one mound). Palm root densities were far higher (up to 10 times) in the nitrogen-rich soil of both clumps and termite mounds than in the surrounding savanna. Evidence is given that palm trees are able to extend their root system as far as 20 m towards these nutrient-rich patches where they proliferate. These results point out a particular root foraging strategy, which is one of the first known for a woody perennial. They also provide new insights for understanding nitrogen cycling and savannas high rate of primary production.     

Sampling subterranean termite species diversity and activity in tropical savannas: an assessment of different bait choices

Abstract.  1. Cellulose baits are commonly used for semi-quantitative sampling of subterranean wood-feeding termites, with a single food choice sampling programme implemented most often. In most situations, however, the composition and feeding preferences of the subterranean termite assemblage remain unknown.
2. The diversity, frequency, foraging activity, and intensity of attack of termites were assessed regularly at 144 baits representing 12 different bait choices over 8.5 months, in two northern Australian tropical savanna sites that differed in vegetation structure (closed vs open). Baits differed in type (paper rolls, cardboard, wooden stakes), position (surface, buried), and moisture status at installation (wet, dry).
3. Sixteen species were recorded, including 11 wood-feeders. Average species diversity, foraging activity, and bait consumption were greater at buried baits than at surface baits. Wooden baits were most attractive early in the experiment, and paper baits more attractive later. Mean species diversity was greatest at wooden stakes in the closed site. Species frequency of occurrence varied across bait choices.
4. A composite bait sampling protocol of stakes and paper rolls installed above and below ground gave an accurate assessment of the activity, diversity, and structure of the termite guild sampled across all baits over 8.5 months.
5. The choice of bait, its presentation, and time of examination are critical to the success of a termite baiting programme. If the aim is to characterise the structure and foraging activity of the subterranean termite assemblages that are attracted to baits, composite baiting protocols should be implemented.     

Temperate forest termites: ecology,biogeography, and ecosystem impacts

1. Wood decomposition in temperate forests is dominated by termites, fungi, and some species of ants and beetles. Outside of urban areas, temperate termite ecology is largely unknown, particularly when compared to tropical termites and other temperate organisms in the functional guild of wood‐decomposing animals. 2. This review combines climate habitat modelling with knowledge of species physiology, behaviour, and community interactions to identify and prioritise future research on temperate termite ecology and biogeography. 3. Using a correlative climate model, the regional distributions of three common temperate forest termite species are shown to correlate with different aspects of climate (e.g. mean versus minimum monthly temperature), but that overall their distributions within temperate systems correlate more strongly with temperature variables than with precipitation variables. 4. Existing data are synthesised to outline how the subterranean, wood‐nesting behaviour of most temperate forest termite species links their activity to an additional set of non‐climate controls: wood type and tree species, soil depth, fungal activity, ant abundances and phenology, and competitive asymmetries among termite species. 5. Although fine‐scale estimates of temperate termite abundances are rare, we provide upper bounds on their ecosystem impacts and illustrate how their regional abundances may influence forest structure and habitat availability for other organisms. 6. This review highlights that rigorous ecological studies in non‐urban, intact ecosystems – with a particular focus on community interactions – are critically needed to accurately project future abundances, economic impacts, and ecosystem effects of temperate forest termites.     

白蚁防治技术

白蚁是破坏性很强的社会性昆虫。文章从白蚁的探测和监测、物理防治、化学防治、生物源物质防治和白蚁信息素的利用技术5个方面综述白蚁防治技术的最新研究进展。同时展望白蚁未来的研究领域。     

Decomposition of tissue baits and termite density along a gradient of human land‐use intensification in Western Kenya

Termites are important decomposers and ‘ecosystem engineers’ in tropical ecosystems. Furthermore, termite assemblages are sensitive to human land‐use intensification and often termite density and the importance of soil‐feeding termites decrease with land‐use intensification. These changes in termite assemblages may also lead to a decrease in termite‐mediated ecosystem processes (e.g. soil formation, cellulose decomposition). We compared density and functional composition of termites with cellulose removal from undisturbed primary forests to farmlands (Kakamega Forest, Western Kenya). In contrast to the expectation, we found no response of termite abundance along the gradient of land‐use intensification. However, as expected, the relative abundance of soil‐feeders decreased from primary forests to farmlands. In contrast, frequency of attack on tissue paper baits and removal of tissue showed a clear hump‐shaped relationship to land‐use intensification with high values in secondary forests. These nonconcordant patterns of density and functional composition of termite assemblages with cellulose removal by termites suggest that it may be misleading to infer changes in a process by the characteristics of the assemblage of organisms that mediate that process.     

Ant‐termite interactions: an important but under‐explored ecological linkage

Animal interactions play an important role in understanding ecological processes. The nature and intensity of these interactions can shape the impacts of organisms on their environment. Because ants and termites, with their high biomass and range of ecological functions, have considerable effects on their environment, the interaction between them is important for ecosystem processes. Although the manner in which ants and termites interact is becoming increasingly well studied, there has been no synthesis to date of the available literature. Here we review and synthesise all existing literature on ant–termite interactions. We infer that ant predation on termites is the most important, most widespread, and most studied type of interaction. Predatory ant species can regulate termite populations and subsequently slow down the decomposition of wood, litter and soil organic matter. As a consequence they also affect plant growth and distribution, nutrient cycling and nutrient availability. Although some ant species are specialised termite predators, there is probably a high level of opportunistic predation by generalist ant species, and hence their impact on ecosystem processes that termites are known to provide varies at the species level. The most fruitful future research direction will be to evaluate the impact of ant–termite predation on broader ecosystem processes. To do this it will be necessary to quantify the efficacy both of particular ant species and of ant communities as a whole in regulating termite populations in different biomes. We envisage that this work will require a combination of methods, including DNA barcoding of ant gut contents along with field observations and exclusion experiments. Such a combined approach is necessary for assessing how this interaction influences entire ecosystems.     

Structure and composition of savanna vegetation in northern Bolivia: A preliminary report

The vegetation of seasonally flooded savannas iin the tropical lowland of the Departamento La Paz, northern Bolivia, was studied. A first collection of vascular plants in this area includes about 600 species, at least three of which are new to the Bolivian flora and four are new to science. The eight major vegetation types distinguished within the savannas are dry bunchgrass savanna (“altura”), seasonally flooded bunch-grass community (“sartenejal”), palm swamp (“palmar”), two types of river floodplains (”bajíos”), a tall shrub community (“chaparral”), the vegetation of termite mounds, and gallery forest. The study area is among the least known in Bolivia. There is a strong need for further studies of these savannas.     

Beta‐Diversity of Termite Assemblages Among Primary French Guiana Rain Forests

Termites are an important component of tropical rain forests, and have been included in many studies focusing on the influence of human disturbance. Their distribution among primary rain forest has, however, rarely been investigated. Here we studied the termite fauna in seven mostly undisturbed forest sites, representing several rain forest types. Overall, approximately 70 percent of species were soil‐feeders and 25 percent were wood‐feeders, the remaining 5 percent being classified here as litter‐feeders. Termite species richness did not differ significantly among sites, but sites differed in termite abundance. The palm swamp and the low forest situated on the foothills of an inselberg, hosted different termite communities to the other sites. These two sites presented a singular physiognomy suggesting that forest type is an important factor influencing species composition. We found no correlation between termite species composition and distance between sites, highlighting that at the scale of our study (about 100 km), forest sites share a similar species pool.     

白蚁信息素研究进展

采用信息素防治白蚁这种世界性害虫是当前白蚁研究的一大热点。本文从化学和生物两个方面总结了几十年来国内外白蚁信息素及其类似物研究进展。讨论了影响信息素活性的几个因素。并根据最新的研究情况,对今后的信息素及其类似物的理论研究和应用情况进行了展望。     

Biological alternatives for termite control: A review

Termites are a serious menace to both plants and structures. They are the most problematic pest threatening agriculture and the urban environment. They cause significant losses to annual and perennial crops and damage to wooden components in buildings, especially in the semi-arid and sub-humid tropics. Chemical control has been a successful method of preventing termite attack, but the effects of these chemicals are of concern as they create problems for our health and the environment. Biological methods could be suitable alternatives in this regard. The present paper reviews the various methods (physical, chemical, and biological) for termite control. Recent advances and past research done on termite control emphasizing biological methods are reviewed. Biological methods described include botanicals (essential oil, seed, bark, leaf, fruit, root, wood, resin), as well as fungal, bacterial, and nematode approaches. The relationship between chemical structure of active components responsible for termite control and termiticidal activity is discussed. The plants reviewed show good insecticidal properties against termites. These botanicals can be used for termite control singly and in combination. The active component from biomass can be extracted to prepare efficacious and potent biocidal formulations.     

Mound-building termites and soil microbial biomass: An interaction influencing termite abundance

Termites are more abundant in the warmer lower latitudinal regions of the earth. Within these broad geographic regions, however, the precise nature of the factors influencing termite abundance is poorly understood. In this paper I have examined the abundance of detritivorous, mound-building termites and certain aspects of the climate, soils and vegetation at 14 sites in tropical northeastern Australia. No relationship between termite mound density and the particle-size characteristics of surface soil horizons, plant available phosphorous or rainfall was found. Microbial biomass carbon level of the surface soil was found to have a strong negative relationship with termite mound numbers. The negative interaction between the soil microbial population and termites may be due to the limiting effect of the organic matter processing capacity of the soil microbial population on the success of termites in occupying the decomposer niche in any particular area. Microbial biomass may therefore be a major factor influencing termite abundance in tropical Australian landscapes and elsewhere.     

Assessment of the contamination and genotoxicity of soil irrigated with wastewater

Soil structures built by litter-feeding termites are one of the main soil translocation processes in dry tropical savanna. Runways (soil sheeting) made of soil particles cemented with salivary secretions covering the dead plant pieces collected on the ground surface represent the main soil structures. The aim of this study was to determine the impact of this soil engineering activity on the microbially-mediated N transformations (nitrification and denitrification) associated with termite sheeting. We investigated the hypothesis that the physicochemical and microbial properties of termite soil sheeting depend on (i) the termite species and (ii) the type of organic substrate consumed. Soil sheeting built by two of the main savanna species, Macrotermes subhyalinus and Odontotermes nilensis, were sampled on field plots treated with three different types of litter (Acacia leaves, millet straw, both whole and ground (< 500 µm), and cattle manure). The soils organic C, total N, inorganic N, microbial biomass, potential CO₂ respiration, nitrification and denitrification were measured. For both termite species and all types of litter, the soil sheeting was enriched in organic C and inorganic N, resulting in an increase in soil respiration, whereas the microbial biomass was unchanged with respect to the reference soil. With the exception of the soil nitrification potential, the type of organic substrate did not significantly affect the properties of the soil sheeting measured. However, the nitrogen cycle was affected differently by the two termite species. In O. nilensis sheeting, the denitrification potential was reduced with respect to the reference soil, whereas the nitrification potential was inhibited in M. subhyalinus sheeting. The changes in the nitrogen cycle processes resulted in an increase in NH₄₊ and NO_3– in the termite soil sheeting, increasing the availability of nitrogen to plants. This study reinforces the importance of termites as a keystone savanna group whose building activities have an effect on tropical soil mineralization.     

Infestation of African savanna ecosystems by subterranean termites

This review is an analysis of the dimensions of termite infestation in African savannas. The aim of this work is to draw the attention of ecologists, conservationists, policy makers and farmers to the current and future threats of subterranean termites to the functioning and sustainability of such ecosystem habitats. This study analyzes and describes termite problem (questionable changes in density and assemblage structure) in selected African savannah ecosystems, synthesizes information on the effects of various human induced habitat disturbance regimes on termites’ assemblage structure, predators, nests and feed resources to generate hypotheses relating termite infestation with anthropogenic activities; it describes and critiques existing termite management practices. The review is suggestive that the infestation and resultant undesirable effects of subterranean termites in African savannahs are largely a consequence of the inappropriate savannah management practices (overgrazing, indiscriminate tree cutting and overhunting) undertaken by humans in pursuit of various livelihood options. Based on the evidence presented herein, we hypothesized that (1) human induced habitat disturbance in savanna ecosystems alters the feeding group composition of termites’ assemblages, favoring grass harvesters and polyphagus termite feeders that forage on more abundant food items, paying little attention to rarer food items and (2) habitat disturbance through activities like heavy grazing and overhunting results in decline in the populations of both macro and microscopic termite predators, which eventually enhances the proliferation of termite populations, escalates the density of termite nests particularly epigeal mounds and intensifies consumption of herbaceous savannah vegetation. The review calls for dedicated efforts to develop ecological thresholds of savannah biotic and abiotic ecosystem components in which human induced disturbance regimes trigger the destructive behavior of termites. This would provide information that will act as a precautionary savannah habitat monitoring and decision support tool to prevent future infestation of savannah habitats with termites. Also, the review shows that majority of the termite control practices are ineffective, ecologically unsustainable and above all, do not address the root cause of termite infestation and thus merely provide temporary relief to the problem. As such, termite control methods that attempt to enhance proliferation of termite predators need to be studied, developed and emphasized. This review reveals that human induced habitat disturbance depletes termites’ predator populations, leading to proliferation of termite populations particularly grass harvesters that intensify their consumption on grass biomass and eventually contribute to denudation of herbaceous vegetation cover in savannah ecosystems.     

The influence of climate on patterns of termite eating in Australian mammals and lizards

Abstract The present paper examines patterns of termite eating in Australian mammals and lizards (total numbers of species, volume percentage of diet) relative to climate (arid, semi-arid, temperate-mesic). Most termite eaters in arid and semi-arid Australia are lizards. Termite consumptio as a proportion of total lizard diet decreases from arid to mesic climates. More mammal species are relatively termite specialized (>50%) in arid than in semi-arid and mesic regions. Termite consumption in echidnas resembles that of the lizards: relatively high in the arid and relatively low in the mesic zone. For the Dasyuridae, termites comprise only a minor fraction (< 10%) in their diet, irrespective of climate. It is argued that the climatic peculiarities of inland Australia (scant and variable rainfall) cause marked seasonality in termite availability, supporting specialized termite eaters in only the most energy-frugal forms (lizards, echidnas). Areas of future research are identified.