Temporal variability in host availability alters the outcome of competition between two parasitoid species.

Variability in the availability of resources through time is a common attribute in trophic interactions, but its effects on the fitness of different consumer species and on interspecific competition between them are not clearly understood. To investigate this, we allowed two parasitoid species, Trichopria drosophilae and Pachycrepoideus vindemiae, to exploit Drosophila host pupae under different temporal variability treatments, either on their own or simultaneously. When tested individually (in the absence of interspecific competition), both parasitoid species had lower fitness when hosts were exposed for a short duration at high density than when exposed for a long duration at low density.

Herbivory limits success of vegetation restoration globally.

Restoring vegetation in degraded ecosystems is an increasingly common practice for promoting biodiversity and ecological function, but successful implementation is hampered by an incomplete understanding of the processes that limit restoration success. By synthesizing terrestrial and aquatic studies globally (2594 experimental tests from 610 articles), we reveal substantial herbivore control of vegetation under restoration. Herbivores at restoration sites reduced vegetation abundance more strongly (by 89%, on average) than those at relatively undegraded sites and suppressed, rather than fostered, plant diversity.

Herbivory by European Earwigs (Forficula auricularia; Dermaptera: Forficulidae) on Citrus Species Commonly Cultivated in California.

Agricultural plant species differ in susceptibility to herbivores; therefore, identifying natural resistances or tolerances to pests can be leveraged to develop preventative, integrated pest management approaches. While many Citrus species are grown in California, most pest management guidelines are based upon research conducted on navel oranges [Citrus sinensis (L.) Osbeck; Sapindales: Rutaceae].

Characterizing Herbivory by European Earwigs (Dermaptera: Forficulidae) on Navel Orange Fruit with Comparison to Forktailed Bush Katydid (Orthoptera: Tettigoniidae) Herbivory.

In establishing Integrated Pest Management (IPM) plans for understudied pests, it is crucial to understand the nature of their herbivory and resulting damage. European earwig (Forficula auricularia L.; Dermaptera: Forficulidae) densities are increasing in citrus orchards in Central California.

Rare plant species are at a disadvantage when both herbivory and pollination interactions are considered in an alpine meadow.

Rare plant species often suffer less damage than common species because of positive density-dependent herbivory, and it has been suggested that this 'rare species advantage' fosters plant species coexistence. However, it is unknown whether rare species have an advantage when pollination interactions are also considered. We hypothesized that a 'positive density-dependent pollination success' across plant species would result in common plants experiencing higher seed set rates compared to rare species, and that positive density-dependent effects would negate or even override the positive density-dependent damage due to herbivory resulting in higher seed loss rates in common plant species.

Profile of Fork-Tailed Bush Katydid (Orthoptera: Tettigoniidae) Feeding on Fruit of Clementine Mandarins.

Sweet oranges (Citrus sinensis (L.) Osbeck Sapindales: Rutaceae) dominated commercial citrus production in California until recently when there has been a shift to mandarins, mostly Citrus reticulata (Blanco) mandarins and Citrus clementina (hort. ex Tanaka) clementines.

Metacommunity robustness of plant-fly-wasp tripartite networks with specialization to habitat loss.

Recent observations have found plant-species-specific fly-host selection (i.e., specialization) of wasp parasitoids (wasps) in plant-fly-wasp (P-F-W) tripartite networks, yet no study has explored the dynamical implications of such high-order specialization for the persistence of this network.

Asymmetric interactions of seed-predation network contribute to rare-species advantage.

Although the asymmetry of species linkage within ecological networks is now well recognized, its effect on communities has scarcely been empirically investigated. Based on theory, we predicted that an asymmetric architecture of antagonistic plant-herbivore networks would emerge at the community level and that this asymmetry would negatively affect community-common plants more than rare ones. We tested this prediction by analyzing the architectural properties of an alpine plant and pre-dispersal seed-predator network and its effect on seed loss rate of plants in the Tibetan Plateau.

Domestic honeybees affect the performance of pre-dispersal seed predators in an alpine meadow.

Flowering plants interact simultaneously with mutualistic pollinators and antagonistic herbivores such that plant-mediated interactions between pollinators and herbivores must exist. Although the effects of herbivores on pollinator behavior have been investigated extensively, the effect of pollinators on herbivore performance has seldom been explored. We hypothesized that insect pollinators could improve the survival and growth of pre-dispersal seed predators by increasing seed production.

Differential responses of body growth to artificial warming between parasitoids and hosts and the consequences for plant seed damage.

Temperature increase may disrupt trophic interactions by differentially changing body growth of the species involved. In this study, we tested whether the response of body growth to artificial warming (~2.2 °C) of a solitary koinobiont endo-parasitoid wasp (Pteromalus albipennis, Hymenoptera: Pteromalidae) differed from its main host tephritid fly (Tephritis femoralis, Diptera: Tephritidae; pre-dispersal seed predator), and whether the plant seed damage caused by wasp-parasitized and unparasitized maggots (larval flies) were altered by warming.

Plant-mediated resource partitioning by coexisting parasitoids.

Although it has been frequently suggested that resource partitioning of species coexisting at the same trophic level can be mediated by interactions with species at non-adjacent trophic levels, empirical evidence supporting this claim is scarce. Here we demonstrate that plants may mediate resource partitioning for two parasitoids that share the same herbivorous host. The tephritid fly Tephritis femoralis is the primary pre-dispersal seed predator of two Asteraceae species, Saussurea nigrescens and Anaphalis flavescens, both of which dominate the plant community in the alpine meadows of the Tibetan Plateau.

Soil drainage facilitates earthworm invasion and subsequent carbon loss from peatland soil.

Human activities have been a significant driver of environmental changes with tremendous consequences for carbon dynamics. Peatlands are critical ecosystems because they store ~30% of the global soil organic carbon pool and are particularly vulnerable to anthropogenic changes. The Zoige peatland on the eastern Tibet Plateau, as the largest alpine peatland in the world, accounts for 1‰ of global peat soil organic carbon storage.

Experimental warming and precipitation interactively modulate the mortality rate and timing of spring emergence of a gallmaking Tephritid fly.

Global climate change is mostly characterized by temperature increase and fluctuating precipitation events, which may affect the spring phenology and mortality rate of insects. However, the interaction effect of temperature and precipitation on species performance has rarely been examined. Here we studied the response of the gall-making Tephritid fly Urophora stylata (Diptera: Tephritidae) to artificial warming, changes in precipitation, and the presence of galls.

The sign of cascading predator effects varies with prey traits in a detrital system.

Theory and experiments show that the nature of 'green' trophic cascades, between predators, herbivores and plants, varies with several key species traits: predator hunting mode and predator and prey habitat domains. Meanwhile, 'brown' cascades between predators, environment-modifying detritivores and plants have been largely overlooked and the roles of species traits, particularly prey traits, in determining the nature of these cascades remains unclear. We hypothesize that, in predator-detritivore-plant interaction chains, the burrowing ability of plant-facilitating detritivores determines their response to predators and thus the sign of indirect effect transmitted.

Artificial asymmetric warming reduces nectar yield in a Tibetan alpine species of Asteraceae.

Background And Aims: Asymmetric warming is one of the distinguishing features of global climate change, in which winter and night-time temperatures are predicted to increase more than summer and diurnal temperatures. Winter warming weakens vernalization and hence decreases the potential to flower for some perennial herbs, and night warming can reduce carbohydrate concentrations in storage organs. This study therefore hypothesized that asymmetric warming should act to reduce flower number and nectar production per flower in a perennial herb, Saussurea nigrescens, a key nectar plant for pollinators in Tibetan alpine meadows.

Parasitoid wasps indirectly suppress seed production by stimulating consumption rates of their seed-feeding hosts.

In parasitoid-herbivore-plant food chains, parasitoids may be simultaneously linked with both herbivore hosts and plants, as occurs when herbivores attacked by parasitoids continue to consume plants although they are destined to die. This peculiar property may cause parasitoids to confer a differential trophic cascading effect on plants than that known for typical predators. We hypothesized that larval koinobiont parasitoids would confer an immediate negative effect on plant seed production by stimulating consumption of their seed-predator hosts.

Artificial warming facilitates growth but not survival of plateau frog (Rana kukunoris) tadpoles in presence of gape-limited predatory beetles.

Background: Global warming has been frequently demonstrated to increase growth rate in larval amphibians that have considerable phenotypic plasticity; this may lead to an increase in larval survival because large larvae are less likely to be captured by gape-limited predators. This study is to test whether warming could improve tadpole growth and thereby enhance the tadpole survival in plateau frog Rana kukunoris.

Methodology: We conducted an experiment involving growing tadpoles under two contrasting temperatures, i.