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Nitrogen fixation is often cited as an important nitrogen source for termites. However, the rate of nitrogen fixation between experiments and termite species is highly variable due to termite diversity and sampling limitations. New evidence suggests that subterranean termites (Coptotermes formosanus Shiraki) (Blattodea, Rhinotermitidae) seek alternative dietary nitrogen sources for colony growth and development. This study compares N2 fixation rates and nitrogenase gene expression rates to a diverse assemblage of feeding groups. It was observed that nitrogenase expression was much higher in one-piece nesting termites from the family Kalotermitidae which lack access to soil. On the other hand, subterranean termites from the family Rhinotermitidae fix nitrogen at much lower rates, not differing from ambient nitrogenase activity in soil. [ABSTRACT FROM AUTHOR]

Facilitating efficient resource transfer requires building an optimized transportation network which balances cost minimization with benefit maximization. For animals which forage for food located remotely, optimizing their transportation networks is critically related to survival. This process often involves finding and using the shortest route to save time and energy. Subterranean termites forage for wood resources by excavating underground foraging networks for search and transport. Because termites have no prior knowledge of food location during the food searching phase, establishment of a short tunnel between the nest and feeding site is difficult at the beginning of foraging. Thus, finding a short route should logically follow initial food discovery. However, it remains elusive as to how subterranean termites find the shortest route for food transportation. We simulated different scenarios using Coptotermes formosanus by providing different shapes and distances of pre-formed tunnels (straight, detour, and detour + twisting arenas) to food, where food items were located at a fixed distance from the arena entrance. Termites in the straight arena continuously used the pre-formed tunnel, showing negligible branching efforts. However, termites in the detour and detour + twisting arenas followed the pre-formed tunnel only for the initial few hours before excavating many branching tunnels. This branching activity ultimately resulted in termites finding shorter commuting routes than the pre-formed tunnels. In addition, the shortest established routes were widened over time. This study demonstrated that C. formosanus could actively alter tunnel networks to minimize the cost in food transportation by using short and wide tunnels. [ABSTRACT FROM AUTHOR]

Tseng, C-T., Su, N-J., Sun, C-L., Punt, A. E., Yeh, S-Z., Liu, D-C., and Su, W-C. 2013. Spatial and temporal variability of the Pacific saury (Cololabis saira) distribution in the northwestern Pacific Ocean. – ICES Journal of Marine Science, 70: 991–999.Logbook data for the Taiwanese Pacific saury fishery and multi-sensor satellite images for 2006–2010 were used to characterize the habitat of Pacific saury (Cololabis saira) in the northwestern Pacific (NWP). An empirical cumulative distribution function (ECDF) approach identified that high cpue (catch per unit of effort) of Pacific saury occurred when sea surface temperature (SST) ranged from 14 to 16°C, chlorophyll-a concentration (Chl a) ranged from 0.4 to 0.6 mg m−3, and net primary production (NPP) ranged from 600 to 800 mg C m−2 d−1. A generalized additive model (GAM) and spatial non-stationary geographically weighted regression (GWR) were applied to predict the habitats of Pacific saury in the NWP. The spatial distributions of Pacific saury in the NWP estimated using the two approaches were similar and matched the nominal cpue distributions and those inferred from preferred habitat ranges based on ECDF. The density of Pacific saury is higher in coastal waters close to the island of Hokkaido and near the southern Kuril Islands than in the open sea. SST, Chl a, and NPP were substantially higher in the fishing grounds for Pacific saury during the main fishing season (September and October), corresponding to a high cpue for Pacific saury (23.1 t fishing day−1). The GAM explained more variability in spatial distribution (35.7%) than GWR (20.5%) VGPM (Vertically Generalized Production Model). Results derived from this study could improve our understanding of Pacific saury habitat distributions, which could be used to forecast fishing grounds and to develop fishery management advice based on oceanographic conditions that might be impacted by climate change. [ABSTRACT FROM PUBLISHER]

Su, N.-J., Sun, C.-L., Punt, A. E., Yeh, S.-Z., DiNardo, G., and Chang, Y.-J. 2013. An ensemble analysis to predict future habitats of striped marlin (Kajikia audax) in the North Pacific Ocean. – ICES Journal of Marine Science, 70: 1013–1022.Striped marlin is a highly migratory species distributed throughout the North Pacific Ocean, which shows considerable variation in spatial distribution as a consequence of habitat preference. This species may therefore shift its range in response to future changes in the marine environment driven by climate change. It is important to understand the factors determining the distribution of striped marlin and the influence of climate change on these factors, to develop effective fisheries management policies given the economic importance of the species and the impact of fishing. We examined the spatial patterns and habitat preferences of striped marlin using generalized additive models fitted to data from longline fisheries. Future distributions were predicted using an ensemble analysis, which represents the uncertainty due to several global climate models and greenhouse gas emission scenarios. The increase in water temperature driven by climate change is predicted to lead to a northward displacement of striped marlin in the North Pacific Ocean. Use of a simple predictor of water temperature to describe future distribution, as in several previous studies, may not be robust, which emphasizes that variables other than sea surface temperatures from bioclimatic models are needed to understand future changes in the distribution of large pelagic species. [ABSTRACT FROM PUBLISHER]

Recent research has shown that a subterranean termite (Coptotermes formosanus Shiraki) is dependent on dietary nitrogen in order to fulfill it's nitrogen requirements for colony growth and development. Crypototermes brevis (Walker) was chosen as a model for comparison, as it has no access to dietary nitrogen outside of it's wood diet. A full nitrogen inventory before and after colony growth was conducted in order to determine the species' dependence on atmospheric N2 fixation. In addition, an expression assay was conducted for a gene encoding a nitrogenase subunit (nifH). Nitrogenase expression was then compared between C. formosanus and Cr. brevis. Results showed that N2 fixation was an important source of nitrogen acquisition for Cr. brevis , and nitrogenase expression was approximately four-fold higher in Cr. brevis than in C. formosanus. The nitrogenase assay used in this study is proposed as a potential tool to measure dependence on N2 fixation versus dietary nitrogen roles in diverse species of termite. [ABSTRACT FROM AUTHOR]

This study compared percentage of total body water (%TBW), water loss rate under desiccative conditions, and cuticular permeability (CP) of four termite species (Order: Blattodea, Infraorder: Isoptera) from different habitats, including one subterranean termite, Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae), one dampwood termite, Neotermes jouteli (Banks) (Blattodea: Kalotermitidae), one 'wetwood' termite, Cryptotermes cavifrons Banks (Blattodea: Kalotermitidae), and one drywood termite, Cryptotermes brevis Walker (Blattodea: Kalotermitidae). There was no consistent pattern associated with the habitat relative humidity (RH) levels and the %TBW among the four termite species tested. Because C. formosanus forage for food, its lowest %TBW may be due to its ability to access water sources, and its need to be more mobile than kalotermitids that remain in wood. Body water loss rate and CP were lower for xeric species such as Cr. brevis than hydric species such as N. jouteli. An RH equilibrium represents the capacity of termite water retention mechanisms that may include the physical structure of cuticular layers, behavioral manipulation of natural openings, and physiological means. As with water loss rate and CP data, RH equilibria were lower for xeric species such as Cr. brevis than hydric species such as N. jouteli. Moreover, RH equilibria for dead individuals of the four termite species were significantly higher than those of live individuals, indicating dead termites lost more water after losing their physiological and behavioral means of retaining water. RH equilibria represent termites' capability in water retention, and there is a strong linear relationship between RH equilibria and CP values. Hence, RH equilibria may offer simpler alternatives to CP estimates. [ABSTRACT FROM AUTHOR]

With recent evidence of hybridization events in the field, the phenotypic traits of F1 hybrid colonies of 2 destructive subterranean termite species, Coptotermes formosanus Shiraki and Coptotermes gestroi (Wasmann) remain to be investigated. In this study, laboratory colonies of 2 conspecific pairings and 2 heterospecific pairings (hybrid F = ♀ C. formosanus  × ♂ C. gestroi , hybrid G = ♀ C. gestroi  × ♂ C. formosanus) were examined in Florida, USA, and in Taiwan. Colony nest architecture for both hybrids displayed disorganized carton materials compared to the defined trabecular carton of both parental species. Soldier head measurements were not a reliable approach for diagnostic purposes, as soldier morphometric traits widely overlapped across all mating combinations, except for hybrid F soldiers displaying abnormally long mandibles. Hybrid F soldiers' mandibles also remained parallel when at rest. However, 4 qualitative morphological differences in soldiers were determined for diagnostic purposes. First, the fontanelle in both hybrids is horizontally ellipsoid whereas subcircular in C. gestroi and trianguliform in C. formosanus. Second, sclerotized striations along the postmental sulcus are present in C. gestroi , absent in C. formosanus , and intermediate in both hybrid soldier types. Third, each lateral margin of the fontanelle is flanked by 2 setae in C. formosanus and both hybrids, while a single seta resides on each side of the fontanelle in C. gestroi. Finally, C. gestroi and hybrid soldiers' heads are characterized by a bulging vertex that is lacking in C. formosanus. Therefore, a combination of these 4 characteristics now allows for soldier identification of hybrid Coptotermes. [ABSTRACT FROM AUTHOR]

Nitrogen, a limiting growth factor in wood-feeding insects, was hypothesized to play a role in the recently discovered behavior of subterranean termites returning to the nest to molt. Coptotermes gestroi (Wasmann) exuviae is approximately 11% N by dry weight, and therefore a potentially rich source of recyclable nitrogen. Exuviae from a C. gestroi colony were marked with immunoglobulin G (IgG) and were fed to two-year-old C. gestroi colonies. IgG-marked exuviae were detected with an enzyme-linked immunosorbent assay. The IgG marker was later detected in every caste and life stage except first-instar larvae (L1). The proportion of individuals positive for the marker varied by caste, with the queens always being positive for the marker. The queens and second-or-higher-instar workers (W2+) had significantly higher concentrations of the marker than the eggs and L1. The trophic path of exuviae includes individuals that directly fed on marked exuviae (workers and possibly second-instar larvae) and individuals that secondarily received marked exuviae through trophallaxis (queens, kings, and soldiers). This study described the trophic path of consumed exuviae and demonstrated its role in the recycling of nitrogen in a subterranean termite. Molting at the central nest may be an efficient means to transfer nitrogen from shed exuviae to recipients and may be a nitrogen recycling behavior conserved from a termite ancestor. [ABSTRACT FROM AUTHOR]

Cellulose is the most abundant polymer in the biosphere, and termites are one of the most important metazoan cellulose processors. Termites are a rich source of digestive enzymes such as endo-β-1,4-glucanases, β-glucosidases, xylanases, amylases, pectinases, and laccases, regardless of whether they are termite derived or of microbiotic origin. Molecular identification of the termite's digestive enzyme is a critical initial step toward using termites as bioresources for industrial applications. Here, we report five β-glucosidase sequences obtained from four species of higher termites (Anoplotermes schwarzi Banks, Macrotermes carbonarius (Hagen), Rhynchotermes bulbinasus Scheffrahn, Sphaerotermes sphaerothorax (Sjoestedt)) with differing nutritional biologies. The deduced amino acid sequences indicated that they were most similar to β-glucosidases in the glycosyl hydrolase family 1 (GHF1). All complete coding sequences are 490 amino acids long and contain conserved motifs involved in substrate binding and catalysis. Each sequence was also predicted to be glycosylated at two sites. [ABSTRACT FROM PUBLISHER]

Chang, Y.-J., Sun, C.-L., Chen, Y., Yeh, S.-Z., DiNardo, G., and Su, N.-J. 2013. Modelling the impacts of environmental variation on the habitat suitability of swordfish, Xiphias gladius, in the equatorial Atlantic Ocean. – ICES Journal of Marine Science, 70: 1000–1012.We developed a habitat suitability index (HSI) model to identify the optimal habitats of swordfish (Xiphias gladius) in the equatorial Atlantic Ocean. Environmental variables, including sea surface temperature (SST), mixed layer depth (MLD), chlorophyll-a concentrations, and sea surface height anomaly, as well as catch and effort data from Taiwanese longline fisheries, were used. The geometric mean model including all the above environmental variables was identified as the most parsimonious model for yielding HSI predictions coinciding with productive fishing grounds with high fishing effort. Swordfish mainly aggregated in the northwest region during March–May and spread southeast thereafter in response to seasonal shifts in oceanographic conditions. There was annual variation in the distribution of habitat patches, and the habitat quality was reduced in the northwest region of the equatorial Atlantic Ocean during 2005. The apparent spatial shifts in optimal habitats might be linked to reduced MLD and elevation in sea surface height, which might be related to climate variability (e.g. Niño-Southern Oscillation and/or Northern Atlantic Oscillation). Because environmental data regarding climate change scenarios are becoming readily available, we can utilize the proposed HSI models to evaluate possible changes in habitat suitability resulting from climate change and provide scientific advice for the development of management regulations. [ABSTRACT FROM PUBLISHER]

Effective entomological surveillance planning stresses a careful consideration of methodology, trapping technologies, and analysis techniques. Herein, the basic principles and technological components of arthropod surveillance plans are described, as promoted in the symposium “Advancements in arthropod monitoring technology, techniques, and analysis” presented at the 58th annual meeting of the Entomological Society of America in San Diego, CA. Interdisciplinary examples of arthropod monitoring for urban, medical, and veterinary applications are reviewed. Arthropod surveillance consists of the three components: 1) sampling method, 2) trap technology, and 3) analysis technique. A sampling method consists of selecting the best device or collection technique for a specific location and sampling at the proper spatial distribution, optimal duration, and frequency to achieve the surveillance objective. Optimized sampling methods are discussed for several mosquito species (Diptera: Culicidae) and ticks (Acari: Ixodidae). The advantages and limitations of novel terrestrial and aerial insect traps, artificial pheromones and kairomones are presented for the capture of red flour beetle (Coleoptera: Tenebrionidae), small hive beetle (Coleoptera: Nitidulidae), bed bugs (Hemiptera: Cimicidae), and Culicoides (Diptera: Ceratopogonidae) respectively. After sampling, extrapolating real world population numbers from trap capture data are possible with the appropriate analysis techniques. Examples of this extrapolation and action thresholds are given for termites (Isoptera: Rhinotermitidae) and red flour beetles. [ABSTRACT FROM PUBLISHER]