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Subterranean termites in the genus Reticulitermes Holmgren 1913 are among the most economically important wood-destroying pests in the western United States. Yet, there remains uncertainty regarding the taxonomy and biology of the species in this genus. The 2 species described as having distributions in this region are the western subterranean termite, Reticulitermes hesperus Banks, and the arid land subterranean termite, Reticulitermes tibialis Banks. Taxonomic studies utilizing cuticular hydrocarbon (CHC) profiles, agonistic behavior, flight phenology, and mitochondrial DNA (mtDNA) suggested that R. hesperus is a species complex comprised of 2 or more sympatric, yet reproductively isolated species. To further delineate these taxa, we examined multiple genes from samples of Reticulitermes collected in the western United States. Alates collected after recent spring and fall mating flights, as well as previously collected workers, were subjected to CHC phenotyping and DNA sequence analyses that targeted mitochondrial cytochrome oxidase subunit II (COII), mitochondrial 16S rRNA, and nuclear Internal Transcribed Spacer 1 and 2 (ITS1 and 2). Phylogenetic analyses conducted also included published sequences of other putative western Reticulitermes species. Results suggest that at least 5 species of Reticulitermes may be present in California and that Reticulitermes in Arizona consistently group into multiple clades, including samples previously identified as R. tibialis in a sister clade. These analyses further support the species status of qualitatively different CHC phenotypes and that alates swarming in spring vs. fall are reproductively isolated species. [ABSTRACT FROM AUTHOR]

Cuticular hydrocarbon (CHC) mixtures from workers of five distinct CHC phenotypes of Reticulitermes Holmgren 1913 from two locations in northern California were examined from monthly collections taken over a 3-yr period. The objectives of this study were (1) to identify and quantify variations of the CHCs of multiple colonies of each of these phenotypes (= species or subspecies) to demonstrate consistency, (2) to assess the potential of CHC mixtures to separate or identify colonies within each phenotype, and (3) to detect any temporal changes in each of the hydrocarbons in the CHC mixtures. Nonmetric multidimensional scaling of all CHC mixtures of all samples collected at both locations separated the samples into five clearly visible, different groups of CHC phenotypes (taxa or species) of Reticulitermes. The degree of variability of the CHC mixtures among colonies of each phenotype was such that nonmetric multidimensional scaling did not separate or identify colonies. Strong seasonal fluctuations were evident in some of the CHCs of all five phenotypes and were significantly consistent with a sine curve. Maximum proportions of seasonal CHCs within a phenotype occurred in all seasons of the year but occurred mostly in the winter and summer. In general, the CHCs displaying maximum values in the winter were short-chained (C23–C27) methyl-branched alkanes, whereas the CHCs displaying maximum values in the summer were long-chained (C35–C43) methyl-branched alkanes, which likely influences water retention. These consistent chemical fingerprints are probably responsible for inter-phenotype recognition patterns and are thus useful for chemical taxonomy. [ABSTRACT FROM AUTHOR]

Acoustic emission (AE) activity patterns were measured from seven loquat [Eriobotrya japonica (Thunb.) Lindl.] logs, five containing live western dry wood termite [Incisitermes minor (Hagen)] infestations, and two without an active drywood termite infestation. AE activity, as well as temperature, were monitored every 3 min under unrestricted ambient conditions in a small wooden building, under unrestricted ambient conditions but in constant darkness, or in a temperature-controlled cabined under constant darkness. Logs with active drywood termite infestations displayed similar diurnal cycles of AE activity that closely followed temperature with a peak of AE activity late in the afternoon (1700-1800 hours). When light was excluded from the building, a circadian pattern continued and apparently was driven by temperature. When the seven logs were kept at a relatively constant temperature (≈23 ± 0.9°C) and constant darkness, the pattern of activity was closely correlated with temperature, even with minimal changes in temperature. Temperature is the primary driver of activity of these drywood termites, but the effects are different when temperature is increasing or decreasing. At constant temperature, AE activity was highly correlated with the number of termites in the logs. The possible implications of these findings on our understanding of drywood termite biology and how this information may affect inspections and posttreatment evaluations are discussed. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate lufenuron termite bait (1,500 ppm) for the elimination of colonies of Reticulitermes hesperus Banks (Isoptera: Rhinotermitidae). Dispersion of colonies in six baited and six unbaited sites near Placerville, CA, was determined by genetic (mic– rosatellite) analyses. Twenty–one colonies of R. hesperus inhabited the six baited sites and eight colonies of R. hesperus occurred in the six unbaited sites. Five criteria provided a cause–and–effect link between the deployment of lufenuron termite bait and elimination of baited colonies: 1) association of foragers, as members of the same colony, in the independent monitoring stations and bait stations; 2) quantity of bait consumed; 3) abnormal physical appearance of foragers in bait stations; 4) disappearance of foragers from, and cessation of feeding in, independent monitoring stations visited by baited colonies; and 5) presence of foragers from, and continuation of feeding in, independent monitors visited by unbaited colonies. Baited colonies were devoid of foraging termites within a mean of 70.6 d (range, 37–93 d) of bait deployment. Colonies consumed a mean of 8.0 g of bait (range, 2.2–16.0 g). Wood consumption by baited and unbaited colonies was not significantly different during the 2 mo before baiting, 281.4 versus 590.5 mg⁄d per colony, respectively, nor during the 3 mo immediately after baiting, 112.5 versus 436.8 mg⁄d per colony, respectively. However, from 10 to 16 mo after baiting, wood consumption by baited colonies essentially ceased and was significantly less than the unbaited colonies, 7.9 versus 470.1 mg⁄d per colony, respectively. [ABSTRACT FROM AUTHOR]

Mark-release-recapture studies were conducted on foraging populations of Heterotermes aureus (Snyder) (Isoptera: Rhinotermitidae) associated with three structures in Tucson, AZ. Foraging population estimates ranged from 64,913 to 307,284 termites by using the Lincoln Index and from 75,501 to 313,251 termites using the weighted mean model. The maximum distance between monitors ranged from 26 to 65 m, with minimum total foraging distance ranging between 297 and 2,427 m. Characterizations of the cuticular hydrocarbons of foraging groups were qualitatively identical. Quantitative similarities within sites and differences among sites suggested that each site was occupied by a single colony during the sampling period. The colony at each site had a proportion of soldiers (0.135, 0.069, and 0.040) that was significantly different from the colonies at each of the other sites. From this study, we question the assumption of equal mixing of marked H. aureus foragers throughout the occupied collars around structures. [ABSTRACT FROM AUTHOR]

Current taxonomic and biogeographical information on Reticulitermes in the United States suggests the only species found in Arizona is Reticulitermes tibialis Banks. Reticulitermes occurs naturally throughout Arizona with the exception of much of the Sonoran and Colorado deserts. Collections of Reticulitermes from disparate locations in Arizona and neighboring states were made to characterize their cuticular hydrocarbons for taxonomic purposes. We identified five phenotypes based on cuticular hydrocarbon mixtures of worker termites. The predominant hydrocarbons in AZ-A have 25 and 27 carbons in the parent chain, including 5,17-dimeC27. The late-eluting compounds are composed primarily of dienes, trienes, a homologous series of internally branched mono- and dimethylalkanes, and 5,17-dimethylalkanes. AZ-B differs from AZ-A by lacking the late-eluting dienes and trienes and by producing smaller amounts of hydrocarbons with 27 carbons in the parent chain. The cuticular hydrocarbons in AZ-C are composed primarily of olefins; C29:1 is the most abundant, and, with C27:1, C31:2, and C33:2, predominates the hydrocarbon mixture. This phenotype also has a homologous series of 5,17-dimethylalkanes from C27 to C43. AZ-D is distinguished by the absence of any 5-methylalkanes, 5,17-dimethylalkanes, or late-eluting dienes or trienes. The hydrocarbon mixture of AZ-D most closely resembles that of Reticulitermes hesperus Banks from northern California. NM-A can be distinguished from the other phenotypes by the significant amounts of the hydrocarbons coeluting in two peaks: C27 + C27:3 and 7-, 9-, 11-, 13-meC27 + C27:2. AZ-A was not common; the few samples we collected were all at the higher elevations, from 2,000 to 2,250 m, in northern Arizona. AZ-B was the most common and was found throughout the state from Fairbank (≈ 1,300m) to Jacob Lake (≈ 2,600 m). This phenotype also was found in eastern Nevada and southern Utah. AZ-C was sympatric with AZ-B over most of the distribution of the latter regions but was elevationally allopatric in southern Arizona. AZ-C occurred at high elevations (>1,500 m) on the desert islands of southeastern Arizona, such as the Santa Catalina, Santa Rita, Chiricahua, and Pinaleno mountains, whereas AZ-B occurred at lower elevations (<1,250 m), usually associated with a riparian area. AZ-D was collected only once in northern Arizona near Jacob Lake, AZ (≈ 1,800 m) but also on Mt. Charleston in southern Nevada. NM-A was collected near Jemez Springs and Chaco Canyon, NM, as well as in the vicinity of Moab, UT. Additional data from morphology, behavior and/or DNA may confirm that these phenotypes represent distinct species as it has with California Reticulitermes. [ABSTRACT FROM AUTHOR]

High-value trees, such as those located in residential, recreational, or administrative sites, are particularly susceptible to bark beetle (Coleoptera: Curculionidae: Scolytinae) attack as a result of increased amounts of stress associated with drought, soil compaction, mechanical injury, or vandalism. Tree losses in these unique environments generally have a substantial impact. The value of these individual trees, cost of removal, and loss of esthetics may justify protection until the main thrust of a bark beetle infestation subsides. This situation emphasizes the need for ensuring that effective insecticides are available for individual tree protection. In this study, we assess the efficacy of bifenthrin (Onyx) and carbaryl (Sevin SL) for protecting: ponderosa pine, Pinus ponderosa Dougl. ex. Laws., from western pine beetle, Dendroctonus brevicomis LeConte, in California; mountain pine beetle, Dendroctonus ponderosae Hopkins in South Dakota; and Ips spp. in Arizona; lodgepole pine, Pinus contorta Dougl. ex Loud., from D. ponderosae in Montana; pinyon, Pinus edulis Engelm. in Colorado and Pinus monophylla Torr. & Frem. in Nevada from pinyon ips, Ips confusus (LeConte); and Engelmann spruce, Picea engelmannii Parry ex. Engelm. from spruce beetle, Dendroctonus rufipennis (Kirby) in Utah. Few trees were attacked by Ips spp. in Arizona and that study was discontinued. Sevin SL (2.0%) was effective for protecting P. ponderosa, P. contorta, and P. monophylla for two field seasons. Estimates of efficacy could not be made during the second field season in P. edulis and P. engelmannii due to insufficient mortality in untreated, baited control trees. Two field seasons of efficacy was demonstrated in P. ponderosal D. brevicomis and P. monophylla for 0.06% Onyx. We conclude that Onyx is an effective individual tree protection tool, but repeated annual applications may be required in some systems if multiyear control is desired. [ABSTRACT FROM AUTHOR]

The diurnal flights of Reticulitermes spp. have been reported to occur in the spring and early fall in northern California. From the spring of 1994 until the fall of 2001, we collected hundreds of alates of Reticulitermes spp. cuticular hydrocarbon phenotypes CA-A/A' and CA-D during flights from multiple locations in the San Francisco Bay Area. As predicted, there were two flight seasons: one in the spring from February to May and one in the fall from October to December. The flights in the spring were made only by phenotypes CA-A/A'; those in the fall exclusively included phenotype CA-D. These disparate flight times indicate that reproductive isolation is complete and provide further biological evidence that phenotypes CA-A and CA-A' are variants of one taxon and are distinct from CA-D. [ABSTRACT FROM AUTHOR]

Presents a study that examined the interactions between worker reticulitermes in California through an agonism bioassay. Factors affecting the expression of agonism; Methodology of the study; Hierarchy in agonism among Reticulitermes phenotypes; Results and discussion.

Long-term growth and survivorship of individual arboreal nests were studied in three species of Neotropical termites in the genus Nasutitermes. Of the 29 N. corniger (Motschulsky) and seven N. ephratae (Holmgren) nests monitored in an area of young second-growth in Panama, 12 (41%) N. corniger and four (57%) N. ephratae nests remained active throughout the 9- to 11-mo study. There was no significant differencein survivorship between small and large nests of either species. In surviving N corniger nests with a single queen, the net increase in volume was highly correlated (r = 0.87, n = 9) with queen wet weight. There was a marked seasonality to nest expansion in both N. corniger and N. ephratae, with growth occurring almost exclusively during the wet season. Seventeen N. acajutlae (Holmgren) nests were monitored for 4-9 yr on Guana Island, British Virgin Islands. Four of the 17 (23.5%) N. acajutlae nests survived the study period, and two more abandoned their original nest and relocated. Within this limited sample of colonies, N. acajutlae nests that were large (> 150,000 cm3) at the beginning of the study had a higher probability of survivalthan did small (<100,000 cm3) nests. Nest budding, relocation, and resprouting are mechanisms that Nasutitermes may use to create a new nest for all or a portion of an established colony. The ontogeny of incipient Nasutitermes colonies is discussed as a sequence in which a young colony remains cryptic within wood, building its population size to a point where the colony can maintain and defend a nest. Early in a wet season, termites then venture from within wood to build and occupy a small arboreal nest. [ABSTRACT FROM AUTHOR]

Seasonal activity of Reticmliterines was observed at 2 sites using AB8 pipe monitoring stations. At a wildland site, 68 of the monitoringstations were occupied by termites during the study; 53, 10. and 5 for hydrocarbon phenotypes A, B, and C, respectively. At the residential site. 26 monitoring stations were occupied; 1-4 and 12, for hydrocarbon phenotypes A' and D. respectively. Live body weights of workersaveraged 2.28, 1.16, and 1.66 mg for phenotypes A. B. and C. respectively, at the wildland site. The workers had similar live body weights at the residential site; phenotype D averaged 2.40 mg, slightly more than the 2.26 mg for phenotype A'. There were no discernible seasonal or monthly trends in live body weights. The percentage of the monitoring stations occupied ranged from 76.7-89.3% and 81.2-93.5% at thewildland and residential sites, respectively deg. . The estimated number of termites was low in the late fall through the early spring and peaked from June to October at the wildland site and peaked from June to November or December at the residential site. Wood consumption by Reticulitermes followed similar trends at both sites. Wood consumption was minimal during the winter, increased slightly in the spring and early summer, peaked in the summer and early fall, then declined in the late fall. Wood consumption reached 1.1-1.3 g per day per monitoring station at the wildland site and 0.8 g per day per monitoring station at the residential site. [ABSTRACT FROM AUTHOR]