Floral nectar usually functions as a pollinator reward, yet it may also attract herbivores. However, the effects of herbivore consumption of nectar or nectaries on pollination have rarely been tested. We investigated Iris bulleyana, an alpine plant that has showy tepals and abundant nectar, in the Hengduan Mountains of SW China. In this region, flowers are visited mainly by pollen-collecting po...

We assessed whether prior foraging by wild herbivores affected foraging behaviour of cattle in Laikipia rangeland, Kenya, during February 2001, August 2001 and February 2002. The study compared cattle bite rate, step rate and bites per step in plots exclusively accessible to cattle and those accessible to cattle and large wild herbivores. During February 2001 when conditions were dry, cattle bi...

Abstract Herbivores select host plants depending on plant quality and the presence of predators competitors. Competing herbivores change quantity through consumption, but they can also induction defences, this affects performance that arrive later plant. Some herbivores, such as spider mite Tetranychus evansi , do not induce, suppress later-arriving profit from suppression. It has been suggeste...

Grasses (monocots), forbs and browse (dicots) differ in structure and chemistry. Grasses have a thicker cell wall containing potentially digestible structural carbohydrates, fewer secondary plant chemicals, and have a relatively low and homogenous growth relative to browses. Mammalian herbivores can be classified along a continuum according to which plant type they prefer. Diet choices correspo...

Thorns, spines and prickles are among the rich arsenal of antiherbivore defence mechanisms that plants have evolved. Many of these thorns are aposematic, that is, marked by various types of warning coloration. This coloration was recently proposed to deter large herbivores. Yet, the mechanical defence provided by thorns against large herbivores might be only the tip of the iceberg in a much mor...

Plants have evolved general and specific defense mechanisms to protect themselves from diverse enemies, including herbivores and pathogens. To maintain fitness in the presence of enemies, plant defense mechanisms are aimed at inducing systemic resistance: in response to the attack of pathogens or herbivores, plants initiate extensive changes in gene expression to activate "systemic acquired res...

Predators can influence primary producers by generating cascades of effects in ecological webs. These effects are often non-intuitive, going undetected because they involve many links and different types of species interactions. Particularly, little is understood about how antagonistic (negative) and mutualistic (positive) interactions combine to create cascades. Here, we show that black bears ...

Endogenous jasmonates are important regulators of plant defenses. If and how they enable plants to maintain their reproductive output when facing community-level herbivory under natural conditions, however, remains unknown. We demonstrate that jasmonate-deficient Nicotiana attenuata plants suffer more damage by arthropod and vertebrate herbivores than jasmonate-producing plants in nature. Howev...

Numerous empirical studies over the past two decades have documented substantial effects of plant toxins on diet choice and feeding behavior of herbivores, but analytical models have failed thus far to incorporate toxin-mediated effects of browsing on plant population dynamics. We study a mathematical model that incorporates plant toxicity in the functional response of plant–herbivore interacti...

It is well documented that ants can protect plants against insect herbivores, but the underlying mechanisms remain almost undocumented. We propose and test the pheromone avoidance hypothesis--an indirect mechanism where insect herbivores are repelled not only by ants but also by ant pheromones. Herbivores subjected to ant predation will experience a selective advantage if they evolve mechanisms...