Termite mounds in relation to the surrounding soils in the forest and derived savanna zones of southeastern Nigeria

Some physical and chemical properties of the two common termite mounds in southeastern Nigeria, Macrotermes (MM) and Cubitermes (CM) mounds, were compared and their relationships with the surrounding top and subsoils investigated. Percentage sand, silt, pH, calcium, magnesium, potassium, sodium, iron, and organic carbon were higher and clay and penetrometer resistance lower in the CM than the MM. Sand, silt, organic carbon, and calcium decreased and clay increased from the forest to the derived savanna in the CM, but no clear trend was shown with the other properties in both the CM and the MM. Most of the nutrients were higher in the CM than in the adjacent top or subsoil but the reverse was the case with the MM. More nutrients are associated with the inorganic fractions of the soil than with the organic carbon in the mounds and the soils surrounding them. The Ca:Mg ratio in the mounds and the top and subsoils adjacent to them was low for most crops but the K:Mg ratio was mostly adequate. Because of these differences in properties and sizes of the mounds, different management strategies are recommended for them and the soils around them.     

白蚁群体融合性及识别因素研究进展

总结了台湾乳白蚁(Coptotermes formosanus)、黑翅土白蚁(Odontotermes formosanus)、大锯白蚁(Microcerotermes crassus)、黄翅土白蚁(Macrotermes barneyi)和尖唇散白蚁(Heterotermes aculabialis)等不同白蚁群体间的融合性,对影响白蚁群体融合的表皮碳氢化合物、肠道菌、季节和巢源地理位置、环境等因素进行了阐述,以期加深对白蚁群体融合性的研究,了解不同种类白蚁群体的融合性,并加以充分利用.     

Irregular Reproductive Cycles in the Tongaland Loggerhead Sea-Turtle,Caretta Caretta L. (Cryptodira: Chelonidae)

The concept of sea-turtles exhibiting regular reproductive cycles is widely accepted. In Tongaland, Natal, after 12 years of research 2122 female loggerhead turtles have been tagged and the recovery rate of tagged animals back on the nesting beaches has reached SO %. From a sample of these recoveries it is clear that there is no regular reproductive cycle and thus that irregularity is characteristic of this population. The most frequent period of absence from Tongaland is two years but few nnimak repeat this absence cyclically. Results so far indicate that a loggerhead female can nest for at least four seasons spread over a period of at least nine years.     

Chemical,physical and micromorphological properties of termite mounds and adjacent soils along a toposequence in Zona da Mata,Minas Gerais State,Brazil

Little is known about the effects of neotropical mound-building termites in soil chemical and physical properties. The influence of soil termite activity on soil characteristics was studied by assessing chemical, physical and micromorphological properties of a toposequence of Latosols (Oxisols). Soil samples were collected from the walls and inner parts of termite mounds and also from adjacent soil. A high diversity of termite genera was found in the mounds along the toposequence, together with the inquiline termites and other soil-dwelling arthropods. Chemical analyses showed that pH and the contents of organic C and N, P, Ca and Mg were significantly higher in termite mounds compared with adjacent areas, with an inverse trend for Al content. Significant differences in pH and exchangeable Al were observed between soil and mound across the slopes. The mound density across the landscape was higher at the upper slope segment, followed by the hill top, middle slope and lower slope segments. Considering a lifespan of 30 years and dimensions of termite mounds found in the toposequence we conclude that the textural and chemical uniformity of Latosols may be increased, following the pedobiological turnover during mound building, with local rates varying from 2.1 to 7.5 m³ ha^− 1.     

Effect of different termite feeding groups on P sorption and P availability in African and South American savannas

Nest structures of six termite species, four with epigeous (above-ground) and two with subterranean nests were analysed to find out how their building and feeding habits could be related to their nests phosphorus status compared with control soils. Termite nest structure was found to affect significantly the P status in savanna soils: mounds of the African Trinervitermes geminatus and the South American Nasutitermes ephratae (both grass-feeders) displayed a greater amount of available P, especially in the inner part of the nest, than the surrounding soil. The abundant quantities of dead grass material stored in the mound can explain the available soil P increase. A similar increase in P availability was also found for the soil-feeder Cubitermes severus. In mounds of Macrotermes bellicosus, on the other hand, there was a drastic increase in P sorption (and a corresponding decrease in available P) compared to adjacent soils, which was attributed to the building strategy of this species. M. bellicosus selected clay from subsoil to build its nest structure. The data obtained for the subterranean species Ancistrotermes cavithorax and Microtermes toumodiensis indicated also that there is an increase in P sorption in mounds when compared with associated topsoils. Consequently, the nest structures of only certain termite species should be considered, and utilised, as a soil amendment in place of fertilisers. This impact on the P cycle in savannas seems to be related to the termite feeding status and to the type of material utilised in nest building. This should be taken into account before using termite nest material in soil fertility status improvement.     

Nutrient storage in soils and nests of mound-building <Emphasis Type="Italic">Trinervitermes</Emphasis> termites in Central Burkina Faso: consequences for soil fertility

Nest structures of two termite species (Trinervitermes spp.) with epigeal (above-ground) mounds were analyzed to compare their nutrient status with that of adjacent soils. To take into account soil variability, the observations and samplings were made in three toposequences of different and representative West African savanna soils. The data showed the high degree of adaptation of these termite species to a large range of soil types and environments. Mounds of Trinervitermes geminatus and Trinervitermes trinervius, both grass-feeders, contained more clay, organic matter (OM), and exchangeable cations than the surrounding surface layer soil. The storage of OM and exchangeable cations was determined for T. geminatus nests and compared to the surrounding soil. Despite substantial nutrient storage in mounds, its total weight appeared low when compared to the nutrient storage in the surrounding 0–15 cm of soil surface layer. This illustrates how contradictory points of view on the use of termite mounds in agriculture need to be clarified using a classical approach that takes into account data by species; and this also evaluates the contribution of different termite mounds to nutrient fluxes and storage and the exact stocking rate of living mounds.     

Consumption and release of nitrogen by the harvester termite Anacanthotermes ubachi navas in the northern Negev desert, Israel

The harvester termite, Anacanthotermes ubachi Navas (Hodotermitidea) occurs throughout the desert regions of Israel. This species nests in subsurface galleries where dead plant material, the termite's main food source, and feces are stored. We measured potential net nitrogen (N) mineralization and nitrification and soil respiration in 7-day laboratory incubations of plant litter at different stages of termite processing, termite feces and termite gallery soil (carton) following wetting. Our objectives were (1) to characterize the amount of potential N release from termite-affected plant and soil materials, (2) to evaluate the potential for leaching of N from the galleries and (3) to make a preliminary evaluation of the importance of termites to the carbon (C) and N cycles of the Negev desert. Two distinct phases were seen in the dynamics of inorganic N during the 7 day incubations: (1) release of N following wetting and (2) immobilization of N from day 1 to day 7 of the incubation. The percent of inorganic N produced in 1 day that disappeared by day 7 was significantly higher in the surface and gallery litter in comparison to the feces and the carton. High levels of nitrate (NO₃⁻: 87.5 g N kg⁻¹) compared to ammonium (NH₄⁺: 4.5 g N kg⁻¹) release from the surface and gallery litter samples suggest that there is a potential for leaching of NO₃⁻ from the galleries to surrounding environments. Gallery litter, i.e. litter that had been processed by termites, released significantly less inorganic N and had a higher C:N ratio than surface litter that had not been affected by termite activity. These results suggest that termites actively remove N for their own nutrition, leaving behind litter of lower quality than was produced by plants. Comparison of the C:N ratios of litter and feces suggest that approximately 80% of the C and 65% of the N in the surface and the gallery litter was decomposed and released in the transformation to feces. Given mean annual biomass production in the study site (740 kg ha⁻¹ with 296 kg C ha⁻¹ and 6.6 kg N ha⁻¹), this decomposition represents a release of 237 kg C ha⁻¹ and 4.3 kg N ha⁻¹, supporting the idea that termites function as keystone species in desert ecosystems.     

硅溶胶预处理对炭化橡胶木防白蚁及阻燃性能的影响

通过硅溶胶浸注预处理获得橡胶木浸注材,再将橡胶木和浸注材分别于185℃和200℃下热改性处理,研究了硅溶胶预处理对炭化橡胶木防白蚁及阻燃性能的影响。结果表明:蚁蛀等级分别从4提升至3.8和4提升至3.75;埋地1 a后完好指数分别从1.3提升至5.9和2.5提升至5.4;氧指数分别提高16.40%和20.16%;EMC无显著变化;气干密度分别提高18.58%和22.03%;弦向气干湿胀率分别降低了10.27%和9.17%,径向气干湿胀率分别降低了15.00%和17.57%;弦向ASE分别提高了21.75%和11.56%,径向ASE分别提高了20.00%和19.71%。     

淮南市白蚁种类调查及分布特点研究

对淮南市白蚁种类进行系统调查,共采集114瓶白蚁标本,经鉴定有白蚁2科2属7种白蚁（另有1种待定）。淮南市白蚁区系分布特点：南北地区白蚁分布比中部少,白蚁在东部的活动范围较中部广,尤以东部大通区蚁害范围最广。室内采到的白蚁基本是危害房屋木构件的散白蚁,野外采集到的白蚁多为危害林木植被的土白蚁。