Groups Of Termites Research Articles

Quantitative and qualitative aspects of trail pheromones in Macrotermes subhyalinus (Isoptera, Termitidae)

In the galleries of Macrotermes a differentiated effect of communication was observed, by which the outward running termites could apparently distinguish between going to a feeding place or to virgin ground of exploration. The aim of this study was to investigate trail-activity in the two situations and to find out whether pheromone trails may transmit specific information about the destination of a trail.¶A new device was developed in which running termites could build up their pheromone trails in the context of their natural activity. Such trails were then bio-assayed with another independent group of termites of the same colony, also during their natural activity within an experimentally defined context of behaviour.¶In the described laboratory experiments, it was shown, that termites of Macrotermes subhyalinus, circulating between the nest and an arena filled with soil (situation of exploration), always laid pheromone trails on the substrate. If two channels coming out from the nest led into two identical arenas, an asymmetry of activity was often observed towards the two channels. This asymmetry was also found in the trail bio-assay when comparing the two trails. If one of two paths, however, led to a foraging arena, this path became significantly more active. In this situation the trail bio-assay yielded astonishing results: if the test termites were in the process of exploration, the trail, that previously led to the soil arena, appeared to be significantly more attractive than the foraging trail, even though it was less frequented during the phase before testing. On the other hand, if the test termites were part of a foraging population, the trail which led previously to the food was dominant.¶These results show that pheromone trails in Macrotermes subhyalinus may include both quantitative and qualitative components. The reaction to such information on the trail varies depending on the motivational context of the receivers.

Kinetics of uptake, clearance, transfer, and metabolism of hexaflumuron by eastern subterranean termites (Isoptera: Rhinotermitidae).

The rates of uptake, clearance, insect-to-insect transfer, and metabolism of [14C] hexaflumuron [N-(((3,5-dichloro-4-(1,1,2,2-tetrafluroethoxy)phenyl)- amino)carbonyl)-2,6-diflurobenzamide] were measured in eastern subterranean termite workers, Reticulitermes flavipes (Kollar), fed cellulose diets containing either 0.1 or 0.5% (wt:wt) hexaflumuron. The rate of uptake, level of maximum uptake, and amount of insect-to-insect transfer were concentration dependent. The clearance rate constant for hexaflumuron was independent of concentration, with a mean value of 3.2 x 10(-3)/h. This corresponds to a mean half-life for hexaflumuron inside termites of 9 d. No evidence of metabolism of hexaflumuron to additional products was detected when extracting and examining the radioactivity contained in the fecal and regurgitated material within the termite holding apparatus 40 d after exposure to the chemical. Hexaflumuron was efficiently transferred from treated to untreated termites, through trophallaxis, resulting in spread of the toxicant throughout the insect population. The combination of uptake and efficient transfer of hexaflumuron between treated and untreated termites ensures broad distribution of the material even to insects not directly exposed to the toxicant. The distribution of hexaflumuron by termite workers, along with their minimal ability to metabolize the compound to other metabolites, and their slow ability to clear the material from the termite population results in death of the entire group of termites contained within the holding apparatus.

Interspecific interactions between Coptotermes formosanus and Reticulitermes flavipes (Isoptera: Rhinotermitidae) in laboratory bioassays.

Experiments were conducted to examine competitive interactions between the Formosan subterranean termite, Coptotermes formosanus Shiraki (FST), and the eastern subterranean termite, Reticulitermes flavipes (Kollar) (EST), using groups of termites with different worker:soldier proportions. Experiments were conducted using three connected test chambers: an FST chamber, an unoccupied center chamber, and an EST chamber. When groups of FST were comprised of 20% soldiers versus 2% EST soldiers, only 8% of center chambers were occupied exclusively by EST. When groups of FST were comprised of 10% soldiers versus 1% EST soldiers, 44% of center chambers were occupied exclusively by EST. When the only food source was located in the center chamber, 60% of center chambers were occupied by both species. FST did not completely displace EST in any of these experiments.

Hunting strategy of a generalist ant species proposed as a biological control agent against termites

AbstractWe studied the hunting behaviour of Myrmicaria opaciventris (Hymenoptera: Formicidae) in order to evaluate if it can be used as a biological control agent against the termites that damage sugarcane plantations. Hunting workers foraged in groups and recruited nestmates at short‐range when they encountered large termite soldiers or groups of small termite workers. Differences in prey capture concerned the: (1) means of detection (from a distance or by contact); (2) termite body part seized (small termites seized by the body; large termites by an appendage); (3) percentages of prey abandoned; and (4) use of venom. The sting of the workers is spatulated implying a topical application of the venom on the prey. Large termites were stretched by several workers whose adherence to the substrate is facilitated by well‐developed arolia and claws on the legs while others spread venom on the body and carved it up. An adaptation to termite capture was noted with a distribution of tasks between the workers which subdued prey, and those which transported it. In the former case, the workers easily eliminated termite soldiers, successively attacked several termite workers and even captured new individuals while holding the first ones captured between their mandibles before retrieving them all at once. The remaining individuals were retrieved by the transporting workers. Given this particularly effective predatory strategy, we concluded that, under certain conditions, M. opaciventris can be used as a biological control agent against termites.

Predatory behaviour in the ponerine ant, Centromyrmex bequaerti: a case of termitolesty

Centromyrmex bequaerti is an African ponerine ant who nests in the termitaries of diverse Termitinae and Macrotermitinae and preys almost exclusively on their hosts. Such predatory specificity corresponds to a kind of familiarisation with the host species, because workers are able to capture other termites when experimentally accustomed. Hunting workers showed different capture behaviours depending on whether they were faced with a single termite worker or soldier, or a group of termites, and were particularly well-adapted to eliminate guarding termite soldiers. The strategy for capturing grouped termites was characterised by the recruitment of nestmates and the piling up of the paralysed prey before retrieving them to the nest. Using a group hunting strategy is considered another evolved feature for this termitolestic ant.

Colony Elimination of Reticulitermes speratus (Isoptera: Rhinotermitidae) by Bait Application and the Effect on Foraging Territory

A natural colony of Reticulitermes speratus (Kolbe), the foraging population and territory of which had been estimated previously by a triple mark-recapture program at the Uji campus of Kyoto University, was used to determine the effect of bait applications. Bait stations and bait tubes containing hexaflumuron were placed in the foraging territory in October 1995 to eradicate the colony. The number of monitoring stations with foraging termites decreased after May 1996 and no attack was observed by July 1996. Because a later inspection in October 1996 demonstrated no further termite attacks of monitoring stations in the foraging territory, the colony that was composed originally of >300,000 foraging termites was considered to be eliminated by bait application. Approximately 33 mg of hexaflumuron was consumed by the colony. Ten months after the end of bait application (May 1997) some termites were present at 3 monitoring stations in the foraging territory of the eradicated colony. Reinfestation of a few more stations was found after June 1997. Because no marked termite individuals were recaptured from any station in the foraging territory of the test colony after elimination by baitings, it was impossible to determine whether this group of termites belonged to the original colony or came from a separate colony. Our results supggest limited applicability of mark-release-recapture methodology to determine colony eradication of R. speratus based on the presence or absence of marked termites.

Latency time and absence of group effect

Summary We suggest that group effect need not be invoked to explain the differences in latency times exhibited by groups of different sizes in the initiation of building in the termite Macrotermes subhyalinus (Rambur). A simple, alternative, model is presented, that is fully consistent with experimental data. In a remarkable series of laboratory experiments Bruinsma (1979) studied the building behavior of the fungus-growing termite Macrotermes subhyalinus, in particular the construction of the royal chamber in the presence of a live physogastric queen. Among his observations is the fact that the time it takes for a group of termites to initiate the building of the royal chamber (which, following Bruinsma, we shall call building “latency time”) is a nonlinearly decreasing function of groups size. Such an observation could be interpreted as resulting from a group effect (Grasse, 1946), or socially facilitated behavior (Clayton, 1978). However, a simple model that does not invoke group effect, fully consistent with the data of Bruinsma (1979), can very satisfactorily account for this observation. The behavior of individual workers during building seems to be made up of relatively few and relatively simple activities: a worker picks up a piece of soil close to or underneath the queen, transports the pellet to a site of deposition (a narrow band around the queen at 2‐5 cm from her and determined by a pheromonal template that she emits), where it deposits and cement it. This behavior, combined with an attraction towards sites where pellets have already been deposited, leads to the formation of pillars or columns a few centimeters away from the queen. Pillars are lengthened until they reach a height of between 0.5‐0.8 cm; workers then start to build horizontal lamellae that grow from the pillars to form a roof over the queen; finally, the interpillar space is filled with pellets to form walls. The building latency time, that is, more precisely, the time elapsed between the introduction of workers in the arena with

Latitudinal gradients in the species richness of Australian termites (Isoptera)

Abstract Using data on the geographic range of 260 described species in the Atlas of Australian Termites, seven ‘regions’ with more complete data, across a wide range of latitudes were selected for further analysis. For these regions, mean species richness (± SE) was calculated for (i) all species from all families, (ii) Termitidae (197 spp.), (iii) Amitermes spp. (Termitidae, 58 spp.), (iv) all families excluding Amitermes spp. (139 spp.), (v) Termopsidae (5 spp.), (vi) Kalotermitidae (32 spp.) and (vii) Rhinotermitidae (25 spp.). In addition, we compared the Atlas data with species richness for five regions, across a comparable range of latitudes, based on the pooled species richness of described and un‐described species given in community studies. No group of termites showed a consistent decline in species richness from tropical to temperate latitudes for either data set. The Atlas data showed similar total species richness from the tropics to the mediterranean southwest, before declining to lowest species richness at the highest latitudes. Species richness of Amitermes spp. and Rhinotermitidae was highest in the southwest. Termopsidae and Kalotermitidae showed no latitudinal pattern in species richness. Community studies showed highest and lowest total species richness in the southwest and at the highest latitudes (south‐coastal Western Australia), respectively, and similar species richness from the tropics to arid central Australia. Species richness of. Amitermes spp. was highest in the southwest (31 spp.). Kalotermitidae and Rhinotermitidae showed no clear latitudinal pattern.The latitudinal patterns of species richness for the Australian termites is consistent with that for the Australian vertebrates and ants in that they differ from patterns established for these taxa on other continents.

The Effects of Habitat Fragmentation and Livestock-Grazing on Animal Communities in Remnants of Gimlet Eucalyptus salubris Woodland in the Western Australian Wheatbelt. I. Arthropods

The effects of habitat fragmentation (remnant biogeographic characteristics) and livestock activity (grazing, trampling) on arthropod communities were examined within 26 remnants of gimlet Eucalyptus salubris woodland in the central wheatbelt of Western Australia. Significant correlations between remnant biogeographic variables were between remnant area and connectivity (+ ve, P < 0001), and between connectivity and distance from the study remnant to the nearest patch of native vegetation (- ve, P < 0.001). Remnant disturbance indices (sheep faecal pellet density, percentage cover of weeds) were significantly correlated with remnant biogeographic characteristics (P < 0.01). Small and poorly connected remnants showed significantly higher intensities of disturbance than larger and better connected remnants. When disturbance indices were used to categorize study remnants into groups with high, moderate or low disturbance, remnants with high intensities of disturbance had significantly less lichen, litter and shrub cover. Highly disturbed remnants were associated with : fewer scorpion species, lower termite and ant diversity (Shannon-Wiener); a lower abundance of scorpions, termites and mygalomorph spiders; more beetle species and higher beetle diversity, and greater abundance of earwigs and beetles. Cockroach, earwig and ant species richness showed no significant response to disturbance. Species richness of termites, and the abundance of lycosid and idiopid (mygalomorph) spiders, isopods, cockroaches and ants, was highest under moderate disturbance. Significant biogeographic covariates were area (abundance of araneaomorph spiders, 'associated subordinate' and 'opportunistic' ants; richness of carabid, scarabid and 'other' beetle species, subordinate and opportunistic ants), connectivity (richness of termites, scarabid beetles) and distance to the nearest native vegetation (richness of 'dominant' ants). When disturbance and biogeographic effects were combined, total termite richness, and the richness of termite functional groups, declined markedly in highly disturbed, small and poorly connected remnants. Termite communities in relatively undisturbed remnants were more similar in species composition to communities in moderately disturbed quadrats than to communities in highly disturbed quadrats. Community similarity values for ants and beetles were similar across the study quadrats with different degrees of disturbance. Arthropod communities were also examined by canonical variate analyses across remnants with different degrees of disturbance, using total abundance and richness, and abundance and richness of predators (scorpions, spiders, carabid beetles, ants) and detritivores/herbivores (termites, isopods, earwigs, cockroaches, weevil and scarab beetles). Effective site separation into the three disturbance categories was found for abundance and richness of all arthropods, and for predators alone. Abundance and richness of detritivores/herbivores separated into two groups of sites: high disturbance sites, and sites with low or moderate disturbance with no separation. In stepwise regression analyses, lichen cover, weed cover and sheep faecal pellet density were the most significant indicators of faunal abundance, richness and diversity. Remnant biogeographic variables explained a low percentage of variation in faunal characteristics. Habitat disturbance was the major influence on the arthropod communities, with remnant biogeographic factors consistently explaining low variations in the abundance or diversity of the fauna. The implications of our findings for the management of remnant vegetation are discussed.

Inter- and intraspecific alarm response in the termiteMacrotermes subhyalinus (Rambur)

In laboratory studies we analysed the reaction of aMacrotermes subhyalinus (Rambur) colony in contact with a small group of test termites placed at the head of a gallery system. As test termites we usedMacrotermes subhyalinus of the same nest,Macrotermes subhyalinus of a foreign nest and the related sympatric speciesMacrotermes bellicosus (Smeathman). Contact with an introduced group of foragers evokes a significant recruitment of workers and minor soldiers. The intensity of the response depends on the test groups we introduced. The highest recruitment results withM. bellicosus andM. subhyalinus from a foreign nest. During the recruitment the increase in the number of minor soldiers is greater than the increase in the number of workers, and as a result, the relative proportion of the soldiers in the population leaving the nest is significantly higher than before. Direct observations at the place of contact show thatM. bellicosus individuals are immediately attacked and killed. In the case ofM. subhyalinus from a foreign nest, not all individuals are killed; some are only intensively examined with the antennae or seized with the mandibles.M. subhyalinus from the same nest are rarely attacked. Mostly they are antennally inspected or enter the gallery system unhindered. The recruitment of termites from the nest is released by major workers which, after contact with the test termites, run back into the nest and provoke an alarm by tactile stimuli. On their way back into the nest the major workers, in all probability, lay a pheromone trail which leads the outgoing alarmed termites towards the place of contact.

Intragroup Conflicts and the Evolution of Sterile Castes in Termites

A hypothesis is proposed to account for the onset of a helper phenotype in the ancestors of termites, for the regular expression of this phenotype by a fraction of the individuals composing the colony, and for the subsequent development and diversification of sterile castes (soldiers and workers) This hypothesis rests on the gradual enhancement of behavioral and physiological traits preexisting in noneusocial ancestors Ancestors of termites probably lived in parent-offspring groups, in which parents assumed reproduction while older offspring helped to raise younger siblings. I demonstrate that conflicts (in particular, competition among helpers to reach the alate stage) are expected within such groups. The ancestral character of such conflicts in termites is substantiated by empirical evidence for their existence in all major groups of extant lower termites, in which they can still play an important role in caste determination I suggest that such conflicts produced individuals with lessened abilities for ...

Estimating Oral Toxicity of Slow-Acting Toxicants Against Subterranean Termites (Isoptera: Rhinotermitidae)

A method is described for estimating oral toxicities (μg/g) of slow-acting toxicants against subterranean termites, Coptotermes formosanus Shiraki and Reticulitermes flavipes (Kollar). Groups of termites were fed with a known amount of medium containing a dye marker and a toxicant. Marked termites were evaluated for daily mortality after total consumption of the medium. Toxicant doses ingested by termites were derived from the total amount of toxicant in the feeding medium and the biomass of termites engaged in that feeding. Using oral LD 50 estimates in μg/g, the total amount of toxicant required to control a field colony can be projected

Nutritional factors affecting methane emission from termites

Because of their numbers and diet, termites are important potential producers of atmospheric methane. This methane production is due to the anaerobic degradation of plant material by a symbiotic microflora localized in the termite's hindgut. The bacterial population and the methane production are correlated to the termite's nutrition mode. The xylophageous termites possess primarily acetogenic bacteria and thus are low methane producers; on the other hand, the soil-feeding and some of the fungus-growing termites have numerous methanogenic bacteria in their guts and produce high quantities of methane but no acetate. It is, therefore, essential to take into account the distribution of the different termite alimentary groups before assessing their global annual methane production.

Division of labour between foraging workers of the ponerine antPachycondyla caffraria (Smith) (Hymenoptera: Formicidae)

Two categories of foraging worker were found inPachycondyla caffraria from Senegal. One specialises in hunting and the other in collecting sweet liquid food. In the category of hunters there are two sub-categories: “stingers” and “transporters”. When the workers were offered a group of live termites (20–30Microcerotermes sp.), two types of behaviour were observed: some workers stung and paralysed the prey, while others transported the termites back to the nest. While on a foraging raid, the two roles are undertaken by two distinct groups of workers, and the roles are not interchanged during the course of the raid. The number of hunters, liquid collectors and transporters of prey are highly correlated with colony size.

Agonistic behavior among colonies of the Formosan subterranean termite,Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), from Florida and Hawaii: Lack of correlation with cuticular hydrocarbon composition

Cuticular hydrocarbon patterns of the Formosan subterranean termite, Coptotermes formosanus Shiraki, were similar among colonies from the same geographical location. Hydrocarbon patterns of Florida colonies were easily distinguished from those of Hawaii colonies by using canonical discriminant analysis. Groups of termites from the same colony did not fight one another when placed in an arena. Intercolonial aggression was not recorded among C. formosanuspopulations from Florida but three colonies from Hawaii fought with the other Hawaiian and three Florida colonies. Of the 12 colonies (six each from Florida and Hawaii) tested, 3 Florida colonies did not direct or receive aggression from any other colony. Cuticular hydrocarbon patterns were not correlated with agonistic behavior.

Preference of the Formosan Subterranean Termite (Isoptera: Rhinotermitidae) for Wood Damaged by Conspecifics

In a laboratory choice-feeding test, groups of termites from five colonies of Coptotermes formosanus Shiraki were presented with wood blocks that had been previously damaged by nestmates; by conspecifics from another colony; by another termite species, Reticulitermes virginicus (Banks); and that had no damage. C. formosanus preferred wood previously damaged by conspecifics, regardless of colony origin, over wood damaged by R. virginicus or undamaged wood. Additionally, they preferred wood damaged by R. virginicus over undamaged wood. Covariate analyses and trail-following assay suggested that the results were almost entirely explained by thigmotaxic cues on the surface of damaged wood blocks rather than on pheromonal cues deposited on the wood.

Chemical heterogeneity of soldier defensive secretions in the desert subterranean termite, Amitermes wheeleri

Soldier defensive secretions were analyzed by GC/MS in eight spatially separated groups of Amitermes wheeleri collected in Arizona and California. Eleven sesquiterpenoids, four of known structure, were isolated. Quantitative and qualitative differences among the groups of termites were extensive; composition of the defensive secretions among colonies varied from one to six components. Intraspecific differences between pairs of sympatric colonies at six sites were much less pronounced. The variability found in A. wheeleri suggests that soldier defensive secretions in the genus Amiterines are not reliable markers for interspecific systematic comparisons.

Implications for comparability of laboratory experiments revealed in studies on the effects of population density on vigour in Coptotermes lacteus (Froggatt) and Nasutitermes exitiosus (Hill) (Isoptera: Rhinotermitidae &amp; Termitidae)

AbstractThe vigour, i.e. survival and wood consumption, of groups of Coptotermes lacteus (Frogg.) and Nasutitermes exitiosus (Hill) was measured when termites were kept at different population densities by changing group size and/or volume of the holding container. A characteristic pattern emerged for subterranean termite species. At low population densities (&lt;0·01 g termites/ml), performance improved with an increase in group size; at higher densities, it tended to decline. The impact of altering group size and container volume on termite vigour was most pronounced at low population densities; at higher population densities, performance tended to be more stable but declined markedly when termites became overcrowded. In most jar-type experiments on termites, especially those conducted in Europe and the USA, small groups of termites are housed in disproportionately large jars, resulting in very low, sub-optimal population densities. Suggestions are made for improvement in experimental design that would lead to an enhancement of the comparability of results from different laboratories.

Termite pathogens: Effects of ingested Metarhizium, beauveria, and Gliocladium conidia on worker termites ( Reticulitermes sp.)

Separate groups of subterranean termites ( Reticulitermes sp.) were exposed to whole cultures of Beauveria bassiana, Gliocladium virens, or Metarhizium anisopliae. Individuals were removed after varying time intervals and hindgut contents were plated onto potato dextrose agar. Viable spores first appeared in the hindguts within 8 hr of exposure. Fungi reisolated from the hindguts of diseased termites were pathogenic of healthy termites. Histological examination showed that invasion of the hemocoel by M. anisopliae occurred exclusively through direct invasion of the integument ca. 24 hr after death. B. bassiana invaded, primarily through the alimentary tract, ca. 12 hr prior to termite death.

Abundance and Distribution of Termites (Isoptera) in a Riparian Forest in the Southern Guinea Savanna Vegetation Zone of Nigeria

Thirty-three species of termites were found in a riparian forest in the Southern Guinea savanna zone of Nigeria. Their total abundance and biomass was 2646 m-2 and 6.90 g m-2, respectively. The dominant trophic group was the soil-feeders (2369 m-2 and 6.18 g m-2), although the wood-feeders (28 m-2 and 0.03 g m-2) were underestimated by excluding the arboreal-nesting Nasutitermes and Microcerotermes, and likewise the fungus-growers (249 m-2 and 0.69 g m-2) by excluding the mound-building Macrotermes. Only three of the 20 species of soil-feeders constructed epigeal nests (mounds), the rest being subterranean. Nearly all species were most abundant in the upper 25 cm; some species moved to deeper levels in the dry season although there were no differences in abundance of species between wet and dry seasons. An adjacent cultivated area, cleared of forest, supported only eight species with an overall abundance of 1151 m-2 and biomass of 5.38 g m-2. The most significant quantitative changes resulting from clearing and cultivation were the decrease in abundance of soil-feeders to 81 m-2 and the increase in abundance (from very rare) of the wood-feeding Amitermes evuncifer to 832 m-2. Thirty-one species were found in a semi-deciduous forest in the forest zone. The abundance and biomass of the subterranean population was 3163 m-2 and 8.0 g m-2, respectively, and, in contrast to the riparian forest, the dominant trophic group was the wood-feeders (2530 m-2), fungus-growers comprised 428 m-2 with soil-feeders (205 m-2) being uncommon. The relative abundance of the different trophic groups of termites in Neotropical, Ethiopian, and Oriental forests is discussed in relation to ecological factors (forest type) and the zoogeographical distribution of the different taxa. FOREST AND SAVANNA are the two major biomes in West Africa south of the Sahara desert. The former occupies a narrow zone adjacent and approximately parallel to the coast, while the latter covers an area north of the forest and extends into semi-arid zones adjacent to the Sahara. Forest consists of evergreen and semi-deciduous trees forming a closed canopy over an open, lower stratum of regenerating trees and a discontinuous herbaceous stratum from which grasses are absent. Savanna consists of semi-deciduous trees forming an olpen canopy over a discontinuous shrub stratum and largely continuous herbaceous stratum dominated by grasses. The boundary between forest and savanna is often abrupt, even less than 50 m wide (Hopkins 1974), and the maintenance of the sharp boundary is aided by annual fires in the savanna and their virtual absence from the forest. Within the savanna zone there are localized areas of forest vegetation, although they are frequently very much reduced in diversity and canopy height and probably provide an environment intermediate between savanna and true forest. They take the form of small patches of forest associated with swamps or moist, shaded localities (forest outliers) or narrow,