Does experience with competition matter? Effects of source competitive environment on mean and plastic trait expression in Erodium cicutarium

Interspecific competition is likely to act as an agent for selection on local scales, although evidence in plants is sparse so far. We hypothesize that in annual shade-avoiding grassland species, heterogeneity in the intensity of aboveground competition for light may shape patterns of genetic variation and induce phenotypic plasticity in traits affecting competitive ability. We collected maternal seed families of Erodium cicutarium from replicated high and low competition environments and exposed them to different levels of aboveground competition in a glasshouse. We examined effects of seed source and competition treatment on expression of plant traits related to competitive ability and fitness. Source environments with high levels of competition were significantly more heterogeneous in competition intensity at both intermediate (approx. 10 m) and small (approx. 0.1 m) spatial scales. Seed source and competition treatment both had highly significant effects on trait expression. Greater intensity of competition experienced by maternal plants was coupled with lower vegetative biomass production and slower growth rates, and at the same time lower abortion rates in the offspring. We interpret these findings as an indication of greater reproductive efficiency in the next generation, in response to competition experienced by parents. There was higher total phenotypic variability in the plants from high competition source sites, but equivalent levels of phenotypic plasticity across source-site competition levels; no costs of phenotypic plasticity were detected. We concluded that differences in competition intensity can lead to trait differentiation in the next generation. For E. cicutarium, experience with competition matters: it leads to substantial phenotypic differences and more total variability in the offspring generation.     

Properties of antibacterial bioboard from bamboo macromolecule by hot press

Bamboo macromolecules were pretreated with bamboo vinegar, which has an antibacterial property, and processed into antibacterial bioboard (ABB) by hot pressing. The ABB was then analyzed by conducting Fourier-transform infrared spectroscopy, thermogravimetric analysis and differential thermal analysis. Results showed that ABB samples had average density of 1.0 g/cm³, which is appropriate for application. The physical and mechanical properties were best for the ABB sample pretreated with bamboo vinegar and hot pressed at 165 °C for 10 min. Fourier-transform infrared spectroscopy revealed that the optimum conditions for hot pressing were a temperature of 165 °C, duration of 10 min, and the addition of bamboo vinegar. Thermogravimetric analysis/differential thermal analysis curves indicated that the thermal degradation of the ABB was less than that of bamboo, revealing that hot pressing increased the thermal stability of ABB samples. Analysis revealed that pretreatment with bamboo vinegar improved the antibacterial property of the ABB.     

3-D numerical investigations into the shear strength of the soil–root system of Makino bamboo and its effect on slope stability

This study attempts to quantify the reinforcement effect of the Makino bamboo (Phyllostachys makinoi Hayata) root system on the stability of slopeland through numerical analyses and in situ tests. Based on the field surveys of Makino bamboo root morphology, a three-dimensional (3-D) numerical model of the soil–root system consisting of the reverse T-shape tap root and hair roots was developed and successfully applied to the finite element simulations of in situ pull-out tests. In the simulations, the soil mass was simulated by a soil element with a perfect elastic–plastic (or Mohr–Coulomb) material model whereas the root system was simulated by a ground anchor element with a linear elastic material model. In addition, a mechanical conversion model with simple mathematical form, which enables a direct transformation of the ultimate pull-out resistance into the shear strength increment of soil–root system was proposed. The conversion model offered a convenient way to quantify the reinforcement effect of the Makino bamboo root system required for the 3-D slope stability analyses. The numerical results indicated that the shear strength increment of the Makino bamboo soil–root system ranged from 18.4 to 26.3 kPa and its effect on the slope stability was insignificant when compared with those adverse influence factors such as the steep slope angle (=50–70°), shallow root depth (=0.8–1.0 m) and large growth height (>10 m) of the Makino bamboo forest slopeland. It can be also speculated that the tension cracks widespread over the slope surface due to the wind loading acting on the bamboo stems and the sequential rainwater infiltration is the dominating factor in the collapse failure of slopeland. For a Makino bamboo forest slopeland with medium slope (25° < slope angle β < 40°), the reinforcement effect of the Makino bamboo root system can mobilize its maximum stabilization capacity when compared with those of slopeland with mild (β < 25°) and steep slopes (β > 40°). Conclusively, the contribution of the Makino bamboo root system to the stability of slopeland is not as significant as expected.     

Analyzing the Spatial Structure of Broughtonia cubensis (Orchidaceae) Populations in the Dry Forests of Guanahacabibes,Cuba

A current key issue in ecology is the role of spatial effects on population and community dynamics. In this paper, we test several hypotheses related to spatial structures and coexistence of epiphytic tropical orchid species with special emphasis on the endemic species Broughtonia cubensis. More specifically, we explored the spatial structure of orchid–host plant communities at three different levels of organization (occupied vs. nonoccupied host trees, trees with B. cubensis vs. other orchids, and reproductive vs. nonreproductive B. cubensis plants). We mapped all potential host trees and orchids at three 20 × 20 m plots and applied techniques of spatial point pattern analysis such as mark connection and mark correlation functions to evaluate departures from randomized communities. We found spatial aggregation of trees with epiphytic orchids and segregation between trees with and without epiphytic orchids, and that there was an intraspecific spatial aggregation of B. cubensis in relation to the other seven epiphytic orchid species. Furthermore, we found spatial aggregation of reproductive B. cubensis individuals and segregation between reproductive and nonreproductive individuals on their phorophytes. Thus, orchid–host plant communities show hierarchical spatial structuring with aggregation and segregation at different levels of organization. Our results point to an enhancement of local species in the coexistence of tropical epiphytic orchid communities, by reducing competition through niche differentiation.     

Do nectar feeders in Andean nature reserves affect flower visitation by hummingbirds?

The interactions among plants and pollinators are crucial for plant reproduction because they structure gene flow among individual plants and among populations of plants. Throughout the Neotropics there has been a strong increase in recent years in the use of artificial nectar feeders in private nature reserves to encourage ecotourism through prolonged observations of hummingbirds. Currently, there is considerable uncertainty whether artificial feeders have a detrimental effect on plant reproduction through competition or a beneficial effect through facilitation. This uncertainty is disconcerting given that nature reserves harbour many rare and endangered plants whose successful reproduction is a conservation goal. To assess whether nectar feeders affected hummingbird visitation to flowering plants, we determined visitation rates in ten flowering species in five Andean nature reserves in Ecuador. We found that visitation rates tended to be higher within 5 m around the feeders than they were at 100 m, 500 m, or 1.5 km distance to the feeders, therefore indicating that nectar feeders tended to facilitate flower visitation at close distance. Because visitation rates at 100 m and 500 m distance from the feeders did not differ from those at 1.5 km, we suggest that feeders do not draw hummingbirds away from flower resources, but if they have an effect on flower visitation at all, they tend to facilitate flower visitation rather than reduce plant reproduction.     

The use of spatial ecological modelling as a tool for improving the assessment of geographic range size of threatened species

We analysed endemic threatened tree and reptile species of Socotra Island (Yemen), characterised by different ecological requirements and spatial distribution, in order to evaluate the usefulness of spatial ecological modelling in the estimation of species extent of occurrence (EOO) and area of occupancy (AOO). Point occurrences for the entire species range were used to model their spatial distribution by Random Forest (RF) and Generalised Linear Model (GLM). For each species the suitability area (SA) was obtained by applying the 0% omission error criterion on the probability map, and compared or integrated with EOO and AOO area obtained by topological methods such as the minimum convex polygon (MCP), α-hull and 2 km × 2 km grid.RF showed a lower prediction error than GLM. Higher accuracy was achieved for species with higher number of occurrences and narrower ecological niche. SA was always greater than AOO measured with the 2 km × 2 km grid method. SA was greater than EOO, measured by both MCP and α-hull methods, for species with localised distribution, while it was smaller for widely distributed species. EOO-α-hull area was equal or smaller than that calculated by MCP depending on the spatial distribution of species. AOO measured considering the SA within the EOO-MCP was greater than that measured using the standard 2 km × 2 km grid. Conversely, AOO calculated considering the suitable area within the EOO-α-hull showed variable results, being smaller or greater than the 2 km × 2 km grid AOO depending on the ecological niche and spatial distribution of species. According to our results, SEM does not provide an effective alternative to topological methods for the estimate of EOO and AOO. However, it may be considered a useful tool to estimate AOO within the boundaries of EOO measured by the α-hull method, because it reduces some potential sources of inconsistency and bias.     

Niche differentiation in rainforest ant communities across three continents

A central prediction of niche theory is that biotic communities are structured by niche differentiation arising from competition. To date, there have been numerous studies of niche differentiation in local ant communities, but little attention has been given to the macroecology of niche differentiation, including the extent to which particular biomes show distinctive patterns of niche structure across their global ranges. We investigated patterns of niche differentiation and competition in ant communities in tropical rainforests, using different baits reflecting the natural food spectrum. We examined the extent of temporal and dietary niche differentiation and spatial segregation of ant communities at five rainforest sites in the neotropics, paleotropics, and tropical Australia. Despite high niche overlap, we found significant dietary and temporal niche differentiation in every site. However, there was no spatial segregation among foraging ants at the community level, despite strong competition for preferred food resources. Although sucrose, melezitose, and dead insects attracted most ants, some species preferentially foraged on seeds, living insects, or bird feces. Moreover, most sites harbored more diurnal than nocturnal species. Overall niche differentiation was strongest in the least diverse site, possibly due to its lower number of rare species. Both temporal and dietary differentiation thus had strong effects on the ant assemblages, but their relative importance varied markedly among sites. Our analyses show that patterns of niche differentiation in ant communities are highly idiosyncratic even within a biome, such that a mechanistic understanding of the drivers of niche structure in ant communities remains elusive.     

Assessment of soil-quality index based on microarthropods in corn cultivation in Northern Italy

The aim of this paper is to assess of the stability and repeatability of the biological soil-quality (BSQ) index over time and at short/long distances in agricultural soils of the Po Valley, Northern Italy, to support its correct use in soil-quality monitoring and is based on soil microarthropods representative of the structure, function and composition of ecological systems, but avoiding classification at the species level. Microarthropods are separated from the soil and weighted using the biological form approach to evaluate their level of adaptation to the soil environment. The field test was organized to assess time and scale effects in a landscape within the coordinates 45°00′ to 45°16′N and 9°50′ to 10°15′E for an estimated area of 200 km². The BSQ had, in different soils cropped with corn and fertilized with sewage sludge, an average value of 76.4 ± 23.5; it appears to be reproducible both over short distances as well as over short periods of time, but no significant differences (p > 0.05) between years nor between farms were observed. In the landscape conditions tested, it appears reproducible and stable at a field and basin scale, though very sensitive to seasonal climatic variations. From a practical point of view, the information reported in this paper contributes to the standardization of the application of BSQ and provides reference values for this index in soils of the Northern Italy cropped with corn.     

Seasonal shifts in seagrass bed primary producers in a cold-temperate estuary: Dynamics of eelgrass Zostera marina and associated epiphytic algae

The seasonal dynamics of seagrass and epiphytic algal primary production were measured in an eelgrass (Zostera marina) bed in the Akkeshi-ko estuary, Hokkaido, Japan (43°02′N, 144°52′E). During spring and early summer, eelgrass biomass increased, with a high production (maximum: 2.89 g C m⁻² day⁻¹), but the production and biomass of epiphytic algae remained low. In contrast, epiphytic algae bloomed in August, with a high production (5.21 g C m⁻² day⁻¹), but eelgrass production ceased and its biomass subsequently decreased. Therefore, the major primary producers in this eelgrass bed switched seasonally from eelgrass in spring and early summer to epiphytic algae in late summer and autumn. Epiphytic algae maintained similar productivity because of the change of photosynthetic kinetics and the dominant epiphytic diatom changed from highly adhesive species to less adhesive or filamentous small species during the bloom. This suggests that the change of epiphyte density and biomass was due to change of its loss rate, possibly due to herbivorous grazing rate. Moreover, competition between epiphytic algae and eelgrass for nutrients and light may also affect the dramatic seasonal changes in the major primary producers.     

On the association of giant short-faced bear (Arctodus simus) and brown bear (Ursus arctos) in late Pleistocene North America

Climate change and human impacts are often implicated in Quaternary megafaunal extinctions. The discovery of associated remains of extinct giant short-faced bears (Arctodus simus) and invading brown bears (Ursus arctos) raises the possibility of competition as another potential factor. We describe fossil remains of both genera from Pellucidar Cave, Vancouver Island, Canada. Analyses of ancient mitochondrial DNA support the identifications of post-cranial brown bear specimens and assign these bears to Clade 4. Our results are consistent with the migration of brown bears from Eastern Beringia to the contiguous United States before the Last Glacial Maximum (LGM) and to Vancouver Island as environmental conditions became favorable after the LGM. Radiocarbon age estimates on these specimens indicate the presence of giant short-faced bears approximately 13.5 thousand calibrated years before present (cal. ka BP; uncalibrated 11,775 ± 30, 11,720 ± 50, and 11,615 ± 30 BP) and of brown bears immediately preceding (～14.5 cal. ka BP; 12,440 ± 35, 12,425 ± 30 BP) and following this time (～13 cal. ka BP; uncal. 11,100 ± 30 BP), suggesting niche partitioning to reduce competition among these species. We suggest that shifts in food availability or quality due to post-glacial vegetation and faunal changes were probably of primary importance in the arrival and the disappearance of giant short-faced bears on Vancouver Island. This study focuses on a key time period and geographic location that is useful in understanding Pleistocene extinctions in North America.     

Effects of intraspecific competition on growth and photosynthesis of Atriplex prostrata

We investigated the effect of intraspecific competition on growth parameters and photosynthesis of the salt marsh species Atriplex prostrata Boucher in order to distinguish the effects of density-dependent growth inhibition from salt stress. High plant density caused a reduction of 30% in height, 82% in stem dry mass, 80% in leaf dry mass, and 95% in root dry mass. High density also induced a pronounced 72% reduction in leaf area, 29% decrease in length of mature internodes and 50% decline in net photosynthetic rate. The alteration of net photosynthesis paralleled growth inhibition, decreasing from 7.6 ± 0.9 μmol CO₂ m⁻² s⁻¹ at low density to 3.5 ± 0.4 μmol CO₂ m⁻² s⁻¹ at high density, indicating growth inhibition caused by intraspecific competition is mainly due to a decline in net photosynthesis rate. Plants grown at high density also exhibited a reduction in stomatal conductance from 0.7 ± 0.1 mol H₂O m⁻² s⁻¹ at low density to 0.3 ± 0.1 mol H₂O m⁻² s⁻¹ at high density and a reduction in transpiration rate from 6.0 ± 0.3 mmol H₂O m⁻² s⁻¹ at low density to 4.3 ± 0.3 mmol H₂O m⁻² s⁻¹ at high density. Biomass production was inhibited by an increase in plant density, which reduced the rate of photosynthesis, stomatal conductance and leaf area of plants.     

Temperature-dependent development models of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) Q biotype on three host plants

Temperature-dependent development of the sweet potato whitefly, Bemisia tabaci (Gennadius), Q biotype was examined on three host plants (bell pepper, oriental melon, and eggplant) at nine temperatures (15, 17.5, 20, 22.5, 25, 27.5, 30, 32.5, and 35 °C). Egg development time (least squares [LS]-mean ± LS-standard error [SE]) varied from 31.78 ± 0.29 days at 15 °C to 4.93 ± 0.25 days at 32.5 °C on bell pepper, from 21.27 ± 0.20 days at 17.5 °C to 4.02 ± 0.23 days at 32.5 °C on oriental melon, and from 26.92 ± 0.19 days at 15 °C to 5.14 ± 0.18 days at 30 °C on eggplant. Nymph development time (LS-mean ± LS-SE) varied from 76.54 ± 0.96 days at 15 °C to 12.96 ± 0.68 days at 27.5 °C on bell pepper, from 48.78 ± 0.38 days at 17.5 °C to 11.32 ± 0.38 days at 32.5 °C on oriental melon, and from 73.08 ± 1.23 days at 15 °C to 11.89 ± 0.70 days at 27.5 °C on eggplant. A non-linear relationship between developmental rate and temperature was described by the Taylor model, and developmental variation was described by the two-parameter Weibull function.     

The systematic position of Hoplitomerycidae (Ruminantia) revisited

Hoplitomeryx Leinders was originally described only on cranial characters. The type specimens were found during the 1970's in karstic fissure fillings, most likely of Messinian age, in Gargano (Apulia, southeastern Italy), between Poggio Imperiale (41°49′30′ N, 15°21′58′ E) and Apricena (41°47′06′ N, 15°26′41′ E). During the 1990's, Hoplitomeryx remains were also discovered in the lower Tortonian layered calcarenites near Scontrone (Abruzzo, central Italy; 41°45′15.55′ N, 14°02′13.23′ E). The skull fragments, teeth, and jawbones from both localities have been examined. The dental characters had never been described before, and also some maxillaries and jawbones were not part of the original sample that was analyzed to establish the genus. Because they possess two lacrimal orifices and closed metatarsal gulley, hoplitomerycids have been linked more closely with Cervids, and accommodated in Cervoidea. A cladistic analysis of a character-taxon matrix of 121 morphological features (48 cranial, 51 dental and 22 postcranial characters) is performed. The analysis shows that hoplitomerycids stem either between antilocaprids and bovids, or antilocaprids and giraffids. They are not linked directly with cervids. Hoplitomerycids likely stemmed from a primitive ruminant stock, perhaps around 29 Ma when a land bridge connected the Abruzzo-Apulia platform with the Balkans across the Adriatic Sea. In the new land, hoplitomerycids developed a mosaic of apomorphic and homoplastic (convergent) character states that recall those found in other higher ruminants.     

Heat coma temperature,relative contents of saturated/unsaturated fatty acids and reproductive maturation in the oceanic sea skaters Halobates micans

This study was performed to clarify how the relative volume of saturated/unsaturated lipid and reproductive maturation relate to resistance to high temperature in the oceanic sea skaters, Halobates micans. Heat coma temperature (HCT) was measured in H. micans adults collected from a fixed sampling location (12°00′N, 135°00′E) in the western tropical Pacific Ocean. After measuring HCT, the specimen were dissected to measure the testes size and to determine the presence and number of oocytes in females. Bodies of the specimen were assessed by lipid analysis to evaluate saturated and unsaturated lipid content. A negative trend was seen between heat coma temperature and percentage of a saturated fatty acid, myristic acid (ratio of carbon number to number of double bonds = 14:0) (Pearson's correlation test: r = − 0.520, p = 0.101). In contrast, a positive trend was detected between heat coma temperature and percentage of an unsaturated fatty acid, palmitoleic acid (16:1) (r = 478, p = 0.137). Young males with small testes showed lower heat coma temperatures, whereas females that showed relatively high heat coma temperatures of 36–40 °C tended to have fewer mature oocytes in their ovaries than those that showed low heat coma temperatures of 30–34 °C. As Halobates appears to exhibit embryonic diapause rather than adult diapause, males of H. micans may develop both testes and resistance to high temperature in the parallel as they grow. In females, a trade-off may occur between heat tolerance function and oogenesis in the oceanic sea skaters.     

Formation of di-d-fructofuranose-1,2′:2,1′-dianhydride by three novel inulin fructotransferases from the Nocardiaceae family

In this work, three novel genes encoding di-d-fructofuranose-1,2′:2,1′-dianhydride (DFA I)-forming inulin fructotransferases (IFTases) from Nocardiaceae family, including Nocardioides luteus, Nocardioides sp. JS614, and Nocardioidaceae bacterium Broad-1, were cloned and expressed in Escherichia coli. The recombinant IFTases from N. luteus (NoluIFTase), Nocardioides sp. JS614 (NospIFTase), and N. bacterium Broad-1 (NobaIFTase) were purified, identified, and characterized. SDS-PAGE analysis showed that they had molecular weights of approximately 41–42 kDa, while gel filtration analysis indicated that their native molecular weights ranged from 50 to 62 kDa, suggesting that the three enzymes may be monomers. Their optimum pH values ranged from 5.5 to 6.0, similar to other DFA I-forming IFTases or di-d-fructofuranose-1,2′:2,3′-dianhydride (DFA III)-forming IFTases. NoluIFTase, NospIFTase, and NobaIFTase exhibited maximal activities at 55 °C, 50 °C, and 45 °C and were stable at 70 °C (for 15 min), 70 °C (187 min), and 55 °C (239 min), respectively. Furthermore, by comparing with our previously reported DFA I-forming IFTase, namely CcIFTase, a probable mechanism for the formation of DFA I by the three new enzymes was speculated, and CcIFTase will be selected for future structural resolution to illustrate the catalytic mechanism of DFA I-forming IFTases toward inulin.     

Combined effects of temperature and interspecific competition on the mortality of the invasive garden ant,Lasius neglectus: A laboratory study

The invasive garden ant, Lasius neglectus, is a dominant species due to its capacity to form large supercolonies. This species was assumed to possess a wide thermal niche since it is able to adapt to cold climates, which is a factor that boosted its rapid expansion from south to many central-northern European Countries. However, the effect of variations in environmental temperatures on its competitive ability against other species has still not been investigated. In this paper, we analyzed the change in survival ability of Lasius neglectus during encounters with two Mediterranean dominant ants (Crematogaster scutellaris and Tapinoma nigerrimum) at four different temperatures (15, 20, 25 and 30 °C). Firstly, control tests were performed to provide the baseline survival ability of the three species at different temperatures. Secondly, competition tests were carried out at the same temperatures. Lasius neglectus survival was negatively affected by high temperature (30 °C) in control tests, and this impairment was much more pronounced in competition tests. On the contrary, the two opponent species were only marginally affected by temperatures in control tests. Crematogaster scutellaris was a better competitor than L. neglectus, particularly at high temperatures. Tapinoma nigerrimum was a weaker competitor and was always outcompeted by L. neglectus, particularly at low temperatures. This result could suggest that L. neglectus is at a disadvantage during interspecific encounters when temperatures are high and that the predicted future increase in environmental temperatures may potentially enhance this handicap.     

Valoración de la musculatura isquiosural en personas mayores

Objectiveto evaluate hamstring flexibility in older adults.Materials and methodsa total of 177 subjects (13 men and 164 women) aged between 43 and 80 years old (mean age = 63.4 ± 6.7 years) who attended fitness classes were evaluated. The mean height was 161 ± 10 cm and the mean weight was 74 ± 5.6 kg. Hamstring flexibility was evaluated using the straight leg raise test.Resultsthe mean flexion in the right hip was 72° ± 13.2° and the mean flexion of the left hip was 72.4° ± 13.8°. No significant differences were found in the values obtained from the straight leg raise test in the left and right legs. For the right leg, 48.02% of the subjects’ values were within the normal range, while 28.81% showed grade I shortness, and 23.61% showed grade II shortness. For the left leg, 49.94% showed normal values, 29.94% showed grade I shortness, and 22.03% showed grade II shortness.Conclusionshalf of the adults and elderly individuals that took part in the present study had hamstring shortness, which increased in frequency with age.     

Biological control of invasive apple snails by two species of carp: Effects on non-target species matter

Molluscivorous fish, especially carp, have been adopted as bio-control agents of the invasive apple snail Pomacea canaliculata, but previous studies have focused on their effectiveness, with little attention paid to their undesirable effects on non-target plants and animals. We conducted an 8-week mesocosm study to compare the effectiveness of two indigenous fish, common carp (Cyprinus carpio) and black carp (Mylopharyngodon piceus), in removing P. canaliculata, and their potential side effects on macrophytes and non-target mollusks in a freshwater wetland. Three species of macrophytes and a community of mollusks in the wetland sediment were enclosed in 1 × 1 × 1 m enclosures either with apple snails (AS), with apple snails and common carp (AS + CC), with apple snails and black carp (AS + BC), or without apple snails and fish. Both species of carp were effective predators of P. canaliculata, removing most of the individuals in the enclosures except a few that were too big to fit into their mouth. By reducing apple snail population, black carp reduced grazing of apple snail on macrophytes. In contrast, although common carp controlled apple snail population, it did not reduce overall loss in plant biomass as the fish might also fed on macrophytes. Both species of carp preyed on non-target mollusks. Application of bio-control agents in invasive species management needs to consider their effects on both the pest and non-target plants and animals. Adoption of common and/or black carp to control apple snail populations thus depends on the weight given to their effectiveness and subtle different effects on non-target organisms by wetland management authority.     

The importance of relative humidity and trophic resources in governing ecological niche of the invasive carabid beetle Merizodus soledadinus in the Kerguelen archipelago

Comprehensive studies to identify species-specific drivers of survival to environmental stress, reproduction, growth, and recruitment are vital to gaining a better understanding of the main ecological factors shaping species habitat distribution and dispersal routes. The present study performed a field-based assessment of habitat distribution in the invasive carabid beetle Merizodus soledadinus for the Kerguelen archipelago. The results emphasised humid habitats as a key element of the insect’s realised niche. In addition, insects faced food and water stress during dispersal events. We evaluated quantitatively how water availability and trophic resources governed the spatial distribution of this invasive predatory insect at Îles Kerguelen. Food and water stress survival durations [in 100%, 70%, and 30% relative humidity (RH) conditions] and changes in a set of primary metabolic compounds (metabolomics) were determined. Adult M. soledadinus supplied with water ad libitum were highly tolerant to prolonged starvation (LT₅₀ = 51.7 ± 6.2 d). However, food-deprived insect survival decreased rapidly in moderate (70% RH, LT₅₀ = 30.37 ± 1.39 h) and low (30% RH, LT₅₀ = 13.03 ± 0.48 h) RH conditions. Consistently, body water content decreased rapidly in insects exposed to 70% and 30% RH. Metabolic variation evidenced the effects of food deprivation in control insects (exposed to 100% RH), which exhibited a progressive decline of most glycolytic sugars and tricarboxylic acid cycle intermediates. Most metabolite levels were elevated levels during the first few hours of exposure to 30% and 70% RH. Augmented alanine and lactate levels suggested a shift to anaerobic metabolism. Simultaneously, peaks in threonine and glycolytic sugars pointed to metabolic disruption and a progressive physiological breakdown in dehydrating individuals. Overall, the results of our study indicate that the geographic distribution of M. soledadinus populations is highly dependent on habitat RH and water accessibility.