Current predictions regarding the ecological consequences of climate change on animal populations are generally autecological and species‐specific, and/or non‐mechanistic extrapolations of recent short‐term patterns. To better understand and predict the effects of climate change on the distribution of species and the abundance of populations we offer a novel, broad theoretical framework. Climate‐induced changes in trophic structure may actually be more predictable than effects on individual species. The logic is that there are general differences in climatic sensitivity among trophic levels – specifically, that as one moves up trophic levels, there is an increase in the temperature sensitivity of vital rates. More precisely, we provide: (1) a formal mathematical definition of distribution limits that is both operational and conceptual, introducing the concept DL50, defined as the geographic and climatic isoline representing an equilibrium occupancy of half of the suitable habitats; (2) a matrix of the possible changes in trophic structure from climate change and the general theoretical consequences; and (3) a new idea that predicts broad effects of climatic warming on trophic systems. Our intention is to help meet the challenge of developing and testing general theoretical models that can predict which species will be winners and losers in ecological time, which evolutionary traits will be favoured or selected against, and what will be consequences for ecosystem structure and function.

One method proposed for moderating the negative effects of habitat isolation is the preservation or restoration of linear landscape elements that structurally link isolated habitat remnants. An understanding of how animals react to landscape elements and move through the landscape is vital for species management and theory development. To achieve this understanding, detailed information on movement rates and specific movement behavior of individual animals in different ecosystems is essential. In an experimental study, we investigated whether individuals of Roesel's bush-cricket ( Metrioptera roeseli ) prefer to use corridors or move over the matrix when they leave a habitat patch. We examined whether movement rates and movement angles in corridors and matrix differed and whether individuals showed edge-avoidance behavior. Differences in these behaviors were analyzed in relation to the softness of habitat edges. We found that approximately 30% more individuals used the corridor than would be expected if dispersal behavior was random. All individuals using the corridor as a dispersal route moved to the end of the corridor and into the surrounding habitat, which is 1000% more than would be expected if dispersal was random. The edge type (hard or soft) did not influence whether individuals moved through corridors or the matrix. Individuals that moved through the corridor moved straighter but slower than individuals that moved over the matrix. A higher movement rate over the matrix than through corridors may be explained by an increased risk of predation, starvation, or dehydration in the open habitat causing individuals to move more quickly toward the higher vegetation. Our results suggest that individuals avoid the edge and the matrix and that the corridor is a preferred alternative for dispersal. We conclude that for this species, and probably other similar species of Orthoptera, linear elements in the form of corridors have a positive influence on the individual's dispersal through the landscape. This demonstrates the value of corridors in reducing the negative effect of habitat fragmentation on the persistence of local species.Efecto de los Corredores y los Bordes del Hábitat Sobre la Conducta de Dispersión, las Tasas de Movimiento y los Ángulos de Movimiento del Grillo de Arbusto de Roesel ( Metrioptera roeseli ) Resumen: Un método propuesto para moderar los efectos negativos del aislamiento del hábitat es la preservación o restauración de los elementos del paisaje lineal que estructuralmente unen remanentes de hábitats aislados. El conocimiento de la forma en que los animales reaccionan a los elementos de paisaje y se mueven a través del paisaje es vital para el manejo de especies y la teoría del desarrollo. Para alcanzar este conocimiento, es esencial conocer información detallada sobre las tasas de movimientos y las conductas específicas de movimiento de animales individuales en diferentes ecosistemas. En un estudio experimental, investigamos si los individuos del grillo de arbusto de Roesel ( Metrioptera...

The emerging insects-as-food industry is increasingly promoted as a sustainable alternative to other animal protein production systems. However, the exact nature of its environmental benefits are uncertain because of the overwhelming lack of knowledge concerning almost every aspect of production: from suitable species, their housing and feed requirements, and potential for accidental release. If ecological sustainability is to be a hallmark of mass insect rearing for consumption, ecologists need to engage in research related to sustainability criteria that are directly linked to key elements of the development of the industry. There is more to this subject than simply comparing feed-conversion ratios (FCRs) of insects to traditional livestock production, and we highlight areas where research needs to be immediately focused.

Summary1. Fragmentation and habitat loss affects both existing and introduced populations. Small habitat areas may have harsher biotic and abiotic conditions, as well as restricting population sizes. Loss of connectivity reduces the opportunities for individuals to move between patches to rescue populations or to re-colonize patches. Knowledge of how landscape composition affects the introduced populations is therefore essential for successful management and future re-introductions. 2.To study the effect of landscape composition and structure on the success of colonization, population growth and dispersal distances, we introduced Roesel's bushcrickets Metrioptera roeseli to 70 habitat islands in areas previously unoccupied by the species. The introduction sites differed in habitat area and connectivity. The population survival and dispersal were then studied for 5 years after initial introductions. 3. In addition to results showing the importance of suitable habitat for population persistence, connectivity in form of linear landscape elements and nodes was also crucial. Linear landscape elements and / or nodes were important for colonization success, growth and dispersal. Linear landscape elements and nodes also reduced the negative effects of unsuitable habitat (matrix) and isolation from suitable habitat and on the populations. 4. These results stress the importance of connectivity in the landscape for population survival and establishment. Consideration of this should be taken into account in both management and re-introductions of bush-crickets and other invertebrates with similar population characteristics and behaviour.

This study evaluated survival and growth of Cambodian field crickets (Teleogryllus testaceus) during captivity when fed a set of local weed species, agricultural and food industry by-products. Wild individuals were caught at two locations in Cambodia, kept in pens and fed commercial chicken feed until the second generation off-spring hatched. First larval stage nymphs from this generation were collected and used in a 70-day feeding trial with one control treatment (chicken feed) and 12 experimental treatments (rice bran, cassava plant tops, water spinach, spent grain, residue from mungbean sprout production, and Alternanthera sessilis, Amaranthus spinosus, Commelina benghalensis, Cleome rutidosperma, Cleome viscosa, Boerhavia diffusa and Synedrela nodiflora). The crickets were kept in plastic cages and feed intake, weight and survival of crickets were recorded weekly. Overall survival did not differ between chicken feed and the experimental treatments with the exception of crickets fed B. diffusa, which had lower survival. From day 35 to day 49, survival on A. sessilis was also lower (P<0.05) than on chicken feed. There was no difference in weight between crickets fed chicken feed, cassava tops and C. rutidosperma. However, crickets fed A. sessilis, A. spinosus and B. diffusa weighed less than those fed chicken feed already at day 21. The feed conversion rate ranged from 1.6 to 3.9 and was ≤1.9 in crickets fed chicken feed, cassava plant tops and C. rutidosperma. Thus this study shows that it is possible, using simple means, to rear Cambodian field crickets. Cassava plant tops and C. rutidosperma both have great potential as cricket feed and the other weeds, with the exception of A. sessilis, A. spinosus and B. diffusa, agricultural and food industry by-products tested, also showed potential.

Assessing the colonizing ability of a species is important for predicting its future distribution or for planning the introduction or reintroduction of that species for conservation purposes. The best way to assess colonizing ability is by making experimental introductions of the species and monitoring the outcome. In this study, different-sized propagules of Roesel's bush-cricket, Metrioptera roeseli, were experimentally introduced into 70 habitat islands, previously uninhabited by the species, in farmland fields in southeastern Sweden. The areas of introduction were carefully monitored for 2-3 yr to determine whether the propagules had successfully colonized the patches. The study showed that large propagules resulted in larger local populations during the years following introduction. Probability of colonization for each propagule size was measured and showed that propagule size had a significant effect on colonization success, i.e., large propagules were more successful in colonizing new patches. If future introductions were to be made with this or a similar species, a propagule size of at least 32 individuals would be required to establish a viable population with a high degree of certainty.

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Aim The bush‐cricket Metrioptera roeselii is an example of an insect which has expanded its indigenous range beyond expectations based on its natural dispersal potential. Understanding how species colonize new areas is vital for formulating effective species conservation programmes and managing invasive species. The aim of this research is to use mitochondrial sequence and microsatellite data to delineate the likely origin and dispersal pathways of M. roeselii in northern Europe. The well‐known ecology of the species and the detailed colonization data make it a very suitable model species for addressing questions relating to invasiveness. Location Fennoscandia, Baltic Sea coast, northern Europe. Methods Using a 676 bp fragment of the mitochondrial cytochrome oxidase subunit I (COI) gene and seven polymorphic microsatellite loci, we genotyped and compared populations at 28 sites within the continuous range of M. roeselii along the Baltic Sea coast, and 10 isolated populations in Denmark, islands in the Baltic Sea and the Scandinavian Peninsula. The acquired data, information on the species' ecology and historical population establishment records were used to infer the colonization history and pathways of this species. Results Both mitochondrial DNA and microsatellite data indicated that several of the isolated populations did not originate from their nearest locations within the continuous distribution area of M. roeselii. Instead, the likeliest source populations were in some cases situated > 500 km from the isolated populations. Hence the first records of appearance in the isolated sites did not coincide with the species' natural expansion but agreed well with the time of colonization of the founder sites inferred from the genetic data. Main conclusions The limited ability of M. roeselii to cross geographical barriers through active dispersal, the inferred colonization pathways from this study, and the knowledge that transport of eggs can potentially occur with agricultural products collectively suggest that at least some of the isolated populations originate from human‐mediated introductions rather than natural dispersal.