Nasute Termites Research Articles

Worker Dimorphism in Nasute Termites Reflects Different Tasks during Food Collection

This study combines information on the differences in foraging behavior and morphological dimorphism for workers of the termite Constrictotermes cyphergaster. We observed through morphological analyzes that the workers of this species are dimorphic. Through comparisons between major and minor workers signal emissions, we can assume that each of these groups of workers performs different foraging tasks. The crop volumes of minor and major workers were measured, noting it are statistically different and this can be associated to differences in food collection. This study also provides information that during the foraging the major workers may be mistaken for soldiers by having a similar posture and coloring, which reduces their predation and enables a quick predator detection due to their position on the trails’ edges.

Evidence for a complex evolutionary history of mound building in the Australian nasute termites (Nasutitermitinae)

Evidence for a complex evolutionary history of mound building in the Australian nasute termites (Nasutitermitinae)

Parallel evolution of mound-building and grass-feeding in Australian nasute termites.

Termite mounds built by representatives of the family Termitidae are among the most spectacular constructions in the animal kingdom, reaching 6-8 m in height and housing millions of individuals. Although functional aspects of these structures are well studied, their evolutionary origins remain poorly understood. Australian representatives of the termitid subfamily Nasutitermitinae display a wide variety of nesting habits, making them an ideal group for investigating the evolution of mound building. Because they feed on a variety of substrates, they also provide an opportunity to illuminate the evolution of termite diets. Here, we investigate the evolution of termitid mound building and diet, through a comprehensive molecular phylogenetic analysis of Australian Nasutitermitinae. Molecular dating analysis indicates that the subfamily has colonized Australia on three occasions over the past approximately 20 Myr. Ancestral-state reconstruction showed that mound building arose on multiple occasions and from diverse ancestral nesting habits, including arboreal and wood or soil nesting. Grass feeding appears to have evolved from wood feeding via ancestors that fed on both wood and leaf litter. Our results underscore the adaptability of termites to ancient environmental change, and provide novel examples of parallel evolution of extended phenotypes.

Sandsitermes gen. nov., a new nasute termite genus from South America (Isoptera, Termitidae, Nasutitermitinae).

We establish herein a new genus of Neotropical termites of the subfamily Nasutitermitinae, Sandsitermes gen. nov.. The new genus accommodates a previously described species, Nasutitermes robustus (Holmgren), and is diagnosed by worker characters, including the mandibles, the gut-coiling configuration in situ, and the pattern of cushions and spines of the enteric valve. We characterized and illustrated the imago for the first time and redescribe the soldier and worker castes of Sandsitermes robustus gen. et comb. nov. from syntypes and other samples from eastern Peru. We support our taxonomic decision, presenting morphological differences between the gut pattern and enteric valve of S. robustus and 13 neotropical Nasutitermes species studied for this report, and discuss possible relationships with other neotropical nasute termites.

Physical and Chemical Characteristics of Soils Modified by Earthworms and Termites

Some physical and chemical properties of earthworm casts and mounds of two termite genera were determined. The objective was to characterize soils modified by soil fauna to highlight their effects on agronomic properties. Results of this study showed that fauna modification alters particle‐size distribution and textural classes of soils. Activities of soil fauna increased soil pH, organic matter content, and exchangeable cations. Furthermore, the contents of nitrogen and phosphorus were increased in soils modified by earthworms and nasute termite relative to the unmodified soil. With regard to micronutrient concentration, earthworm casts contained higher concentrations of copper (Cu), molybdenum (Mo), and manganese (Mn) than the other soil materials. Based on macro‐ and micronutrient contents, soils reworked by earthworms and nasute termites appear to have high potential for agronomic use.

Revision of the termitophilous tribe Pseudoperinthini (Coleoptera: Staphylinidae) in New Guinea

AbstractUntil now only one species of the tribe Pseudoperinthini, Austrointhus papuanus, was known from New Guinea. Here, we report the presence of five additional species, four of which are new to science: one species in the genus Pseudoperinthus, one in Austrointhus and two in Papuinthus, new genus. All were found in association with nasute termites of the genera Nasutitermes, Tumulitermes, Niuginitermes and Diwaitermes (subfamily Nasutitermitinae). The absence of distinctive characters and the presence of intermediate species suggest that Indinthus should be considered a synonym of Austrointhus. Some Pseudoperinthini species occur over a broad range and with several related host termites, whereas other species appear to be narrowly distributed and host species-specific. This pattern suggests local speciation, but may also result from insufficient sampling effort.

Family-Group Names for Termites (Isoptera)

Thirty-nine available family-group names are identified within the insect order Isoptera (termites). For all names the correct author, date, type genus, and combining stem are provided for the first time. This nomenclatural compilation is done to stabilize the usage of family- group names in the Isoptera in advance of a world catalog. Several problems of priority are identified and discussed. The little understood subfamily Foraminitermitinae is diagnosed; while generally believed by many authors to be a new, unnamed subfamily, it was in fact established by Holmgren nearly a century ago. The subfamilies Syntermitinae and Sphaerotermitinae are newly proposed for the mandibulate genera of nasute termites and for Sphaerotermes, respectively. The classification of Isoptera is briefly outlined.

Soldier morphogenesis in a nasute termite: discovery of a disc-like structure forming a soldier nasus.

Nasute termites belonging to the subfamily Nasutitermitinae, have a soldier caste that possesses a frontal projection (nasus) on the head, from which defensive substances are secreted. In the course of caste differentiation of the processional nasute termite Hospitalitermes medioflavus, the most dynamic morphogenesis occurs in the stage of moulting from male minor worker to presoldier (the stage preceding the soldier stage). We examined the presumptive nasus epithelium in minor workers and determined that the nasus develops rapidly just prior to the moulting to presoldiers. The rapid growth is associated with two folding layers of cuticle and epithelium, which we termed the soldier-nasus disc, and resembles the imaginal discs found in holometabolous insects.

Environmental Factors Related to the Occurrence of Mound-Building Nasute Termites in Trachypogon Savannas of the Orinoco Llanos

The incidence of termite mounds was determined in twenty-six sites in the Trachypogon savannas at the Orinoco Llanos, including a wide range of physionomic types. A multiple discriminate analysis was utilized to analyze ecological variables as the best indicators of a given area's suitability for support of terrestrial Velocitermes and/or Nasutitermes species. The variables included physical attributes (texture, ineffective soil mass, water holding capacity, and infiltration rate), chemical attributes (cation exchange capacity, base saturation, and organic matter content), soil characteristics, and the above-ground phytomass accumulated at each stand. Results indicated that soil physical variables determining water balance during critical dry periods were of paramount value for the successful establishment of mound-building nasute termites in Trachypogon savannas.

From tetracycles to macrocycles: Chemical diversity in the defense secretions of Nasute termites

Soldiers of the advanced genera of nasute termites (Isoptera: Termitidae: Nasutiternitinae) eject an irritating glue-like defensive secretion containing novel polycyclic cembrene-A derived diterpenes in a monoterpenoid solvent. These soldiers have lost their mandibles through evolutionary processe, but they have developed the ability to biosynthesize diterpenes which is unique in insects. Soldiers of some genera of the primitive mandibulate nasutes produce normal alkanes and simple mono- and sesquiterpenes, while others possess a homologous series of extraordinarily large-ringmacrocyclic lactones containing 22 to 36 carbon atoms. Spectral details for the macrocyclic lactones and hydroxylactones are presented in this paper, and the biochemical, ecological and evolutionary significance of these chemicals will be discussed.

Nitrogen sources for neotropical nasute termites: Fixation and selective foraging.

Studies with Nasutitermes and Rhynchotermes (Isoptera, Nasutitermitinae) in a Costa Rican rainforest suggest that nitrogen fixation by gut symbionts may play a significant role in termite nutrition. Leaf-litter feeders ingest more and fix less nitrogen than do wood-litter feeders; both species feed preferentially on N-rich foods in their foraging repertoire. Unusually high N2 fixation (acetylene reduction) rates were found in Nasutitermes soldiers, thereby reducing their nutritional dependence on workers. Finally, N2 fixation rates of termites diminished rapidly within 24 h after removal of a colony from the field, underlining the importance of conducting future N2 fixation studies under field conditions.

Chemical Ecology: Studies from East Africa

The International Centre of Insect Physiology and Ecology (ICIPE), in Nairobi, provides a laboratory at which a multinational group of scientists pursues interdisciplinary research. In collaboration with their colleagues in biology, ICIPE chemists have characterized the sex pheromones of the tick which serves as a vector of East Coast fever and have identified a termite queen-cell-building pheromone. The structure of many anthropod defensive chemicals have been determined; most interesting of these are the trinervitenes, structurally novel diterpenoids from nasute termites. Several highly active insect antifeedants were discovered using a simple bioassay to screen selected East African plants. These antifeedants may provide leads for the development of new insect-control techniques.