Functional ecology of feeding in elasmobranchs

Feeding behavior in the species of captive chondrichthyans is studied to clarify the functional mechanisms responsible for feeding ecology. Kinematics and pressure in the buccal, hyoid and pharyngeal regions were quantified in Squalus acanthias, Chiloscyllium plagiosum and Leucoraja erinacea using sonomicrometry and pressure transducers. Means and coefficients of variation were analyzed by species and by behavior to test for stereotypy and flexibility in the feeding mechanism. Several instances of mechanical stereotypy as well as flexibility were found in the feeding kinematics and pressure of the three chondrichthyan species. In general, Squalus acanthias shows more stereotyped feeding behavior than C. plagiosum and L. erinacea. Different aspects of feeding behavior stand out among the three species. Chiloscyllium plagiosum generates lowest pressures, S. acanthias achieves the greatest area changes, and L. erinacea has longer durations for manipulating prey. Capture events are functionally and behaviorally stereotyped while processing events are functionally and behaviorally flexible with the ability to use suction or compression to process the same food item. Squalus acanthias is a functional specialist and C. plagiosum is functionally a generalist, with both species exhibiting behavioral flexibility. Leucoraja erinacea is a functional and behavioral generalist. Using functional morphology to explain mechanical stereotypy and flexibility in the feeding behavior of three suction feeding chondrichthyan species has allowed a better understanding of specialist and generalist trophic behaviors.     

Phytoplankton ecology of Loch Achray (Scotland)

Loch Achray is a warm monomictic lake in the Scottish highlands with water temperature ranging from 4 °C to 18.7 °C. The oxygen distribution is mainly clinograde with saturation values ranging from 76 to 112%. The general pattern of nutrient variation is irregular particularly for phosphate. Dissolved silica (measured as silicate) showed a range of 24 μg at. Si l⁻¹; phosphate varied from 0.24 to 0.03 μg at. P l⁻¹ while nitrate ranged from 3.5 to 15.2 μg at. N l⁻¹. The pH remained below 7 for the entire year and the alkalinity was very low, ranging from 2.5 to 6 mg CaCO₃ 1⁻¹. The examination of net samples showed Loch Achray to possess a poor phytoplankton population, consisting mainly of desmids and a few diatoms. The quantitative investigation showed a different picture of variation. There was no clear phytoplankton increase till May when a simultaneous increase occurred involving Melosira, Asterionella, Tabellaria fenestrata and Cyclotella. In July the population was dominated by Anabaena, while Cyclotella and Staurastrum became dominant in August.     

Morphology and ecology of Pacific sturgeons

The six North Pacific members of the genus Acipenser have generally similar environmental requirements and share several specific morphological features. This Pacific group consists of green sturgeon, Acipenser medirostris, Sakhalin sturgeon, A. mikadoi, white sturgeon, A. transmontanus, Chinese sturgeon, A. sinensis, Dabry’s sturgeon, A. dabryanus and Amur sturgeon, A. schrenkii. A qualitative morphological examination of these species revealed synapomorphic characters that suggest close phyolgenetic relationships resulting from common ancestry of eastern and western species within the Pacific Rim. An evolutionary taxonomic approach, considering a reduction of characters from east to west, would suggest an Asian ancestry for all Pacific sturgeons. In contrast however, a phylogenetic approach using derived character states suggests a North American ancestry. Besides a common ancestry for Chinese and American sturgeons, the taxonomic status of A. mikadoi is discussed.     

Taxonomy, phylogeny, and ecology of the heliobacteria

Heliobacteria are a recently discovered group of anoxygenic phototrophic bacteria, first described in 1983. Heliobacteria contain bacteriochlorophyll g, a pigment unique to species of this group, and synthesize the simplest photosynthetic complexes of all known phototrophs. Also, unlike all other phototrophs, heliobacteria lack a mechanism for autotrophy and produce endospores. Four genera of heliobacteria containing a total of 10 species are known. Species of the genera Heliobacterium, Heliobacillus, and Heliophilum grow best at neutral pH, whereas species of Heliorestis are alkaliphilic. Heliobacterium, Heliobacillus, and Heliophilum species form one phylogenetic clade of heliobacteria, while Heliorestis species form a second within the phylum Firmicutes of the domain Bacteria. Heliobacteria have a unique ecology, being primarily terrestrial rather than aquatic phototrophs, and may have evolved a mutualistic relationship with plants, in particular, rice plants. The genome sequence of the thermophile Heliobacterium modesticaldum supports the hypothesis that heliobacteria are “minimalist phototrophs” and that they may have played a key role in the evolution of phototrophic bacteria.     

Understanding the ecology of mammalian carnivorans and herbivores from Valdegoba cave (Burgos, northern Spain) through stable isotope analysis

Stable carbon and oxygen isotope analyses of mammalian carnivoran and herbivore species from the late Pleistocene Valdegoba cave site in northern Spain imply competition and partitioning in resource use. In general, the data support the previously recognized ecology for the analyzed species. δ¹³C values show that the ecosystem around the cave was dominated by C₃ plants. The observed δ¹⁸O values are similar to what is found in modern environments. The analyzed bovids, Bos primigenius, Capra pyrenaica, and Rupicapra rupicapra, showed the most positive δ¹³C values. Bos primigenius had the most positive mean carbon isotope value and is suggested to feed on grasses in open environments. Values for Capra pyrenaica primarily indicate grass feeding, while Rupicapra rupicapra had the widest diet for the analyzed species, likely including grass and browse. Cervus elaphus, Equus ferus, Equus hydruntinus, and Stephanorhinus hemitoechus displayed more negative δ¹³C values indicating the use of similar resources. The smallest species analyzed, Castor fiber, displayed the most negative δ¹³C and δ¹⁸O values, implying a preference for eating C₃ plants and being semi-aquatic. The canids, Canis lupus and Vulpes vulpes, displayed the most positive δ¹³C and δ¹⁸O values, and overlap many of the sampled ungulate species. Positive δ¹⁸O values in canids implies that this group obtains much of its water from its prey, uses a different water source, or has physiological differences from the other carnivorans that influence oxygen isotope values. Lynx pardinus had values similar to the canids. Crocuta crocuta had δ¹³C values more negative than expected for a generalist predator. These values are likely due to concentration of diet on taxa from more forested environments. The most negative δ¹³C values are observed in the bears, Ursus arctos and Ursus spelaeus. These values are the likely result of hibernation and the inclusion of significant vegetation in bear diets.     

种子微生物生态学研究进展

植物种子微生物生态学是研究与种子相联合的微生物的组成﹑功能﹑演替、它们之间关系及其与宿主之间相互关系的科学。种子中蕴含着丰富的微生物资源,它们对种子以及植物的健康具有重要的影响。不同种类植物种子联合的微生物群落由于受到种子本身及外界环境因素的影响而有所差异。论述了种子微生物生态学的概念、主要研究方法、种子微生物生态系统中的微生物种类、相关影响因素,以及种子微生物生态学研究的发展方向。种子微生物生态学的研究对生产实践有重要意义,同时也将丰富种子生物学的内容,对种子科学的发展起到促进作用。     

General base-catalyzed ester hydrolysis as a model of the “charge-relay” system

The validity of the “charge-relay” system in serine esterases was examined by use of the general base-catalyzed hydrolysis of ethyl chloroacetate (I) as a model system. The general base catalytic rate for 2-benzimidazoleacetic acid (II) exhibited an eightfold positive deviation from the Brønsted plot including benzimidazole, imidazole, N-methylimidazole (V), and acetate ion, though in nucleophilic catalysis of the hydrolysis of p-nitrophenyl acetate, the point for II conformed to the Brønsted relationship together with imidazole and benzimidazole derivatives. The positive deviation of II from the Brønsted plot for the general base-catalysis was attributed to the cooperativity of the carboxyl group of II, the imidazolyl group of II, and the hydroxyl group of water. The present result provides support for the “charge-relay” system. Furthermore, the (essentially) total loss of the enzymatic activity due to N-3 methylation of histidine-57 in α-chymotrypsin is discussed in comparison to the general base-catalysis of V in the hydrolysis of I, which is also favorable for the “charge-relay” system.     

The ecology of primate material culture

Tool use in extant primates may inform our understanding of the conditions that favoured the expansion of hominin technology and material culture. The ‘method of exclusion’ has, arguably, confirmed the presence of culture in wild animal populations by excluding ecological and genetic explanations for geographical variation in behaviour. However, this method neglects ecological influences on culture, which, ironically, may be critical for understanding technology and thus material culture. We review all the current evidence for the role of ecology in shaping material culture in three habitual tool-using non-human primates: chimpanzees, orangutans and capuchin monkeys. We show that environmental opportunity, rather than necessity, is the main driver. We argue that a better understanding of primate technology requires explicit investigation of the role of ecological conditions. We propose a model in which three sets of factors, namely environment, sociality and cognition, influence invention, transmission and retention of material culture.     

The ecology of aero-aquatic hyphomycetes

We observed 35 species of aero-aquatic hyphomycetes belonging to 21 genera and 4 unidentified taxa of the Clavariopsis, Dactilella, Helicoon, and Tetracladium genera. Substrate preferences were detected in some species. Species such as Anguillospora longissima, Tetracladium marchalianum, and Fusarium aqueductum were found on different types of substrata. Only 11 species are developed on pine needles, while 20 species were observed on leaves. Eight species of aquatic hyphomycetes (Alatospora acuminata, Angullospora aquatica, Lemonniera aquatica, Tetracladium setigerum, Tricladium angulatum, Tripospermum campelopardus, Septonema secedens, and Spermospora sp.) were revealed on leaves taken from water habitats, whereas 15 species were found in litter. The jointly grown species did not demonstrate any inhibiting effects on each other except for Tripospermum campelopardus, which inhibited the growth of other species (Table 3). The microcyclic development of a Dactilella sp. was detected for the first time while being incubated on leaves in the laboratory. The frequency of appearance changes, and the diversity of the species of aquatic hyphomycetes appears to be higher on intact leaves than on skeletonized ones. The seasonal dynamics of aquatic hyphomycetes with two peaks of mass conidia development (vernal and sharper autumnal) were described. Some species were observed throughout the entire vegetation season. The conidial development in the leaf samples incubated in the laboratory lasted for 30–40 days. Therefore, the method of incubation for 7–10 days recommended in the literature did not allow for the complete investigation of species diversity in aquatic hyphomycetes.     

Reproductive ecology of four subtidal red algae

The reproduction and stature of the red algae Callophyllis cristata (C. Ag.) Kuetz., Membranoptera alata (Huds.) Stackh., Phycodrys rubens (Huds.) Batt., and Ptilota serrata Kuetz. were recorded from subtidal populations at Appledore Island, Maine, U.S.A., with respect to time and depth. Only Membranoptera alata exhibited a conspicuous seasonal fluctuation of reproduction. A vertical gradient of reproduction was evident, with reduced levels of reproduction in shallow populations of Phycodrys rubens and Ptilota serrata, as well as deep populations of Phycodrys rubens, Membranoptera alata and Callophyllis cristata. Differential stratification of the reproductive phases of Ptilota serrata occurred with higher frequencies of tetrasporic plants in deep populations and of cystocarpic plants in shallow populations. In contrast, the haploid and diploid plants of the other three species showed similar distributional patterns. Membranoptera alata, Phycodrys rubens, and Callophyllis cristata showed a conspicuous decrease in stature during maximum reproduction.     

Diversity and ecology of fungal assemblages present in lake sediments at Clearwater Mesa,James Ross Island,Antarctica, assessed using metabarcoding of environmental DNA

We detected the fungal assemblages present in lake sediments on James Ross Island, Antarctica, using DNA metabarcoding. A total of 132 amplicon sequence variants (ASVs) were assigned, dominated by taxa of the phyla Ascomycota, Basidiomycota, Mortierellomycota and Mucoromycota. The less common phyla Chytridiomycota, Rozellomycota, Monoblepharomycota, Basidiobolomycota, Aphelidiomycota and the fungus-like Straminopila were also detected. Fungal sp. 1, Fungal sp. 2, Spizellomycetales sp. 1, Rozellomycotina sp. 1, Talaromyces rubicundus and Betamyces sp. dominated the assemblages. In general, the assemblages displayed high diversity and richness, and moderate dominance. Saprophytic, pathogenic and symbiotic fungi were detected. The metabarcoding data indicated that Antarctic lakes may represent a hotspot of fungal diversity in Antarctica. The sediments of these lakes may accumulate different fungal fragments and active fungal mycelia and their propagules, deposited over long periods of time. Lakes in the Antarctic Peninsula region are sensitive environments threatened by the effects of regional climatic changes. The abundance of sequences of little-known Rozellomycota and Chytridiomycota (Spizellomycetales) taxa in these ecosystems highlights the need for further studies to identify if they are metabolically active in the sediments and whether they have potentially pathogenic capabilities.     

珍稀药用植物白及光合与蒸腾生理生态及抗旱特性

以珍稀濒危药用植物白及(Bletilla striata)叶片为研究对象,应用Li-6400XT便携式光合仪分别在晴天和阴天进行光合生理生态特性研究。结果显示晴天Gs、Pn、Tr日变化呈现双峰型,阴天为单峰型;光合-蒸腾具有极显著线性正相关关系与良好的线性耦合关系(晴天和阴天的相关系数分别为0.883^**、0.954^**,回归直线斜率分别为2.38、3.78);PAR-Pn与PAR-Tr、Tl-Pn与Tl-Tr、Gs-Pn与Gs-Tr 的回归直线形态非常相似,除晴天Tl与Pn外,其余两两相关关系均达到了显著水平;PAR、Tl和Gs三个因子与Pn、Tr均表现为正相关关系,其中Gs是调控Pn与Tr的最主要因子。进行聚乙二醇6000(PEG6000) 渗透胁迫实验以评价白及抗旱能力,分析不同质量分数PEG6000(0、5、20、40、60g/L)下的白及幼苗叶绿素含量、叶片含水量、相对电导率3个生理指标,结果表明叶绿素含量与与胁迫浓度呈负相关(R²=0.7854),随着PEG质量分数的增加,叶片的叶绿素含量持续显著下降;叶片含水量与胁迫浓度呈负相关(R²=0.9936);相对电导率与与胁迫浓度呈正相关(R²=0.8755),相对电导率会随着PEG质量分数的增加而显著增加。试验结果综合分析显示白及为耐荫植物,抗旱能力不强。白及进行人工栽培应适当遮阴保持土壤与空气湿度。     

An adaptive and robust biological network based on the vacant-particle transportation model

A living system reveals local computing by referring to a whole system beyond the exploration-exploitation dilemma. The slime mold, Physarum polycephalum, uses protoplasmic flow to change its own outer shape, which yields the boundary condition and forms an adaptive and robust network. This observation suggests that the whole Physarum can be represented as a local protoplasmic flow system. Here, we show that a system composed of particles, which move and are modified based upon the particle transformation that contains the relationship between the parts and the whole, can emulate the network formed by Physarum. This system balances the exploration-exploitation trade-off and shows a scale-free sub-domain. By decreasing the number of particles, our model, VP-S, can emulate the Physarum adaptive network as it is attracted to a food stimulus. By increasing the number of particles, our model, VP-D, can emulate the pattern of a growing Physarum. The patterns produced by our model were compared with those of the Physarum pattern quantitatively, which showed that both patterns balance exploration with exploitation. This model should have a wide applicability to study biological collective phenomena in general.     

田湾核电站海域浮游动物生态特征

2009年8月在田湾核电站附近海域进行了海洋浮游动物及环境因子的调查,在14个调查站位共鉴定浮游动物10大类43种.其中原生动物5种,水螅水母类17种,栉水母类2种,枝角类2种,桡足类11种,糠虾2种,樱虾类1种,磷虾1种,毛颚类1种,被囊类1种.浮游动物的丰度范围为99-2546个/m3,平均值为834个/m3.主要优势种为薮枝螅水母、太平洋纺锤水蚤、背针胸刺水蚤、鸟喙尖头潘、异体住囊虫、汤氏长足水蚤、强壮箭虫.优势度分别为0.804、0.586、0.569、0.485、0.197、0.140、0.116.各类指数变幅较大(种类数为9-17,丰富度指数为0.913-1.770,多样性指数为1.170-3.212,均匀度指数为0.369-0.803).多样性指数均值为2.188,均匀度指数均值为0.587,丰富度指数均值为1.336.相关性分析表明,水温与浮游动物丰度及种类数之间具有显著的相关性,相关系数(r)分别为-0.615和-0.574,P＜0.05;种类数与多样性指数、丰富度指数及均匀度指数有显著的正相关,相关系数(r)分别为0.730、0.759(P＜0.01)和0.552( P＜0.05),水温升高使浮游动物种类数减少;水温与氨氮含量之间有极显著的正相关性,氨氮含量与浮游动物种类数之间有极显著的负相关性,水温升高使氨氮上升引起浮游动物种类数下降,温排水导致调查海域水温升高引起了浮游动物群落多样性指数、丰富度指数及均匀度指数的下降.调查海域水质状况的生物多样性指数评价显示,目前该海域水质总体处于轻度污染.     

Sayl andghayl: The ecology of water allocation in Yemen

In this article, comparison is made between the two major types of water allocation systems in Yemen: seasonal flood (sayl)and highland spring flow (ghayl).Constraints in the nature of water as a flowing resource are defined for each system. The major distinctions between the two types of systems are variability in water flow (which influences the determination of access rights), techniques of water control, measurement of water turns, the need for supervision of irrigation activities, and the potential for economic expansion of the production system. It is argued that tribal political organization is an adaptive response to highland spring flow allocation in Yemen, but undergoes stress in coastal flood systems where competition for the same water source extends across tribal boundaries in upstream-downstream conflict.     

Co-operative response of chemically excitable membrane III. Three-state model

The general three-state model is formulated first, which is the direct extension of the unified two-state model previously formulated (Kijima & Kijima, 1978). In this model, each protomer in a symmetrically interacting system (oligomers or lattices) can take three states, S, R and Q, where S and R states are the same as in the two-state model and Q state is another state either corresponding to a different open-state of ionophore from R open-state or corresponding to another closed state of ionophore. The model has no restriction on the value of Hill coefficient at the midpoint of the dose-response curves in contrast to two-state models. It is applied on GABA sensitive inhibitory synapse of crayfish muscle to account for anomalous behaviour of the membrane in I^? solution.The simplified versions of the above general three-state model are also formulated (simplified three-state model), in which it is assumed that R and Q state are equivalent in regard to the nearest neighbor interaction. By this assumption, R and Q state are collectively treated as state A and mathematical formula obtained on Ising model are applicable on this model. This model is applied on the insect sugar receptor which was shown to be incompatible with the two-state models (Kijima & Kijima, 1980). Further simplification of the above simplified model results in two convenient models: three-state KNF model and three-state MWC model, which have minimum parameters but sufficient to account for most experiments. They give plausible physico-chemical base on the “classical model” in which the existence of both inactive and active ligand-receptor complex is assumed.     

Reproductive ecology of the basal angiosperm Trithuria submersa (Hydatellaceae)

Background and Aims

Trithuria, the sole genus in the family Hydatellaceae, is an important group for understanding early angiosperm evolution because of its sister relationship to the ancient lineage, Nymphaeales (water lilies). Although also aquatic, Trithuria differs from water lilies in that all species are extremely small, and most have an annual life form and grow in seasonal wetlands. Very little is known about their reproductive ecology. This paper reports on reproductive timing, mode of pollination and characteristics of the breeding system of Trithuria submersa in Western Australia.

Methods

Mass collections of open-pollinated plants from different ecological settings were used to characterize the reproductive developmental sequence and natural pollen reception. Hand-pollination, caging and emasculation experiments were used to measure outcross + geitonogamous pollen reception versus autonomous self-pollination in two populations over two field seasons.

Key Results

Natural outcross or geitonogamous pollination was by wind, not by water or insects, but pollen reception was extremely low. Pollen production was very low and pollen release was non-synchronous within populations. The pollen to ovule (P/O) ratio was 23·9, compared with 1569·1 in dioecious Trithuria austinensis. Stigmas became receptive before male phase and remained so until anthers dehisced and autonomous self-pollination occurred. Natural pollen loads are composed primarily of self pollen. Self- and open-pollinated plants had equivalent seed set (both >70 %). Self-pollinated plants produced seed within 17 d.

Conclusions

Autonomous self-pollination and self-fertilization are predominant in T. submersa. The low P/O ratio is not an artefact of small plant size and is inconsistent with long-term pollination by wind. It indicates that T. submersa has evolved a primarily autogamous breeding system. Selfing, along with the effect of small plant size on the speed of reproduction, has enabled T. submersa to colonize marginal ephemeral wetlands in the face of unpredictable pollination.     

Life cycle,physiology, ecology and red tide occurrences of the fish-killing raphidophyte Chattonella

The marine fish-killing raphidophytes of the genus Chattonella currently consist of five species, i.e. C. antiqua, C. marina, C. minima, C. ovata and C. subsalasa. The distribution of Chattonella species was confirmed in tropical, subtropical and temperate regions in the world accompanying mass mortalities of fishes in nature and in aquaculture. The fish-killing mechanisms are still unclear, but suffocation is the ultimate cause of fish death. Increasing evidence is pointing towards the generation of reactive oxygen species (ROS, e.g. superoxide), which are responsible for the gill tissue injury and mucus production that leads to death of fishes. A taxonomic revision was proposed based on morphology and genetic diversity that Chattonella antiqua and Chattonella ovata should be varieties of Chattonella marina possessing nomenclatural priority. Optimum temperatures for growth are 25 °C for C. antiqua and C. marina, 25–30 °C for C. ovata and 20–30 °C for Chattonella subsalsa. Adequate ranges of salinity for growth were about 20–30 for Chattonella species. Chattonella cells generally divide once a day. Laboratory culture experiments with artificial synthetic medium demonstrated that C. antiqua, C. marina and C. ovata used only Fe chelated with EDTA for growth, although tested diatoms and dinoflagellates used rather many kinds of chelated Fe. A suitable concentration of humic acid supplied with iron also had enhancing effects on the growth of C. antiqua. Diel vertical migration was observed in Chattonella, and the cells reached 7.5 m deep at night in the case of C. antiqua demonstrated by a mesocosm experiment in the Seto Inland Sea. Chattonella species have diplontic life history and have haploid cyst stage in their life cycle. Encystment was observed through formation of pre-encystment small cells after the depletion of nitrogen, and the small cells sink to the sea bottom to complete cyst formation by attachment to the solid surface such as diatom frustules and sand grains. Newly formed cysts are in the state of spontaneous dormancy and they need cold temperature period of four months or longer for maturation (acquisition of germination ability). Cysts germinate in early summer and resultant vegetative cells play an important role as seed populations in blooming in the summer season. However, relatively small part of cyst populations actually germinate from bottom sediments, and success of red tide formation is dependent on the growth in water columns. Since red tides of Chattonella were observed when diatoms were scarce in seawater, diatoms appear to have a key for the predominance of Chattonella in water columns. Diatom resting stages in sediments need light for germination/rejuvenation, whereas Chattonella cysts can germinate even in the dark, implying the selective germination of Chattonella cysts at the sea bottom under calm oceanographic conditions which contribute to bloom formation of Chattonella. As a mechanism of red tide occurrences of Chattonella in coastal sea, “diatom resting hypothesis” was presented. Biological control using diatoms is proposed through the germination/rejuvenation of resting stages suspending from bottom sediments to euphotic layer by sediment perturbation with submarine tractors or fishing trawling gears. Since diatoms have much higher growth rates, and newly joined diatom vegetative cells grow faster and prevent occurrence of Chattonella red tides as a result. As another prevention strategy for Chattonella red tides, algicidal bacteria inhabiting in seaweed beds and seagrass beds are presented. Co-culture of fish and seaweeds in aquaculture areas, and the developments of seaweed- and seagrass-beds would be practical and ultimately environment-friendly strategies for the prevention of harmful red tides of Chattonella by virtue of natural algicidal bacteria supplied from seaweeds and leaves of seagrass.     

The physiological ecology of the supratidal amphipod Talorchestia longicornis

Physiology, behavior, habitat, and morphology are used to determine the degree of adaptation to life on land for amphipod species and systemization within the four functional groups of the family talitridae. Talorchestia longicornis is a semi-terrestrial amphipod found in the supratidal zone of estuaries. The present study investigates the physiological adaptations of this species to life on land through measurements of osmoregulation and respiration. Over the salinity range of 1-40‰, T. longicornis regulated its hemolymph hyperosmotically at low salinities and hypoosmotically at high salinities. The isosmotic point was about 27‰. Analogously, hemolymph chloride levels were well regulated being hyperionic at low salinities and hypoionic at high salinities. This species is capable of respiration in both air and water. Slopes (b values) of the relationship between weight and oxygen uptake rates ranged from 0.316 to 0.590. Oxygen uptake rates were higher in air than water and at night versus day. Q₁₀ values were slightly below 2.0 for respiration in air for amphipods, irrespective of weight. These physiological adaptations, along with its behaviors, habitat, and morphology, place T. longicornis within the Group III sandhoppers of the Talitridae.