Many plants that bear hidden or recessed floral nectar experience nectar robbing, the removal of nectar by a floral visitor through holes pierced in the corolla. Although robbing can reduce plant reproductive success, many studies fail to find such effects. We outline three mechanistic hypotheses th

Premise of the Study – Flowering time may influence pollination success and seed set through a variety of mechanisms, including seasonal changes in total pollinator visitation or the composition and effectiveness of pollinator visitors. Methods – We investigated mechanisms by which changes in flower

The outcome of species interactions is often difficult to predict, depending on the organisms involved and the ecological context. Nectar robbers remove nectar from flowers, often without providing pollination service, and their effects on plant reproduction vary in strength and direction. In two ca

Pollinator-mediated reproductive isolation is often a principal factor in determining the rate of hybridization between plant species. Pollinator preference and constancy can reduce interspecific pollen transfer between otherwise interfertile, coflowering species. The importance of this ethological

Changes in the morphology and physiology of Ipomopsis aggregata and changes in en- vironment were assessed along a roughly 1000 m elevation gradient at seven sites in the Rocky Mountains of central Colorado. Sites at the ends of the gradient had the lowest soil moisture, the lowest two being in sage

Hybridization between interspecific angiosperms is common, yet the initial stages are rare (REF- is this even true????). One of the factors that aeffects the rate of hybridization is the behavior of pollinators responsible for transferring pollen and fertilizing the flowers – only for some plants. P

The basic tenet of sex allocation theory is that an organism's reproductive success, through either male or female function, can be represented as a sex-specific, monotonic, increasing function of the organism's investment of resources in that function. The shapes of these curves determine what patt

Based on previous studies, extreme ( 99%) self‐sterility in scarlet gilia (Ipomopsis aggregata) appears to be involved in late‐acting ovarian self‐incompatibility (OSI). Here, we confirm this suggestion by comparing structural events that follow from cross‐ vs. self‐pollinations of I. aggregata. Gro

ABSTRACT Territorial behavior of Broad-tailed (Selasphorous platycercus) and Rufous (Selasphorous rufus) hummingbirds in Colorado was measured at sites with feeders containing10%, 20%, and 30% sucrose solutions, respectively. The presence or absence of territory holders, number of intruders, and int

Despite the strong influence of pollination ecology on the evolution of selfing, we have little information on how distinct groups of insect pollinators influence outcrossing rate. However, differences in behavior between pollinator groups could easily influence how each group affects outcrossing ra