Little is known about the breeding systems of perennial Lupinus species. We provide information about the breeding system of the perennial yellow bush lupine, Lupinus arboreus, specifically determining self-compatibility, outcrossing rate, and level of inbreeding depression. Flowers are self-compatible, but autonomous self-fertilization rarely occurs; thus selfed seed are a product of facilitat...

Biodiversity is increasingly subjected to human-induced changes of the environment. To persist, populations continually have to adapt to these often stressful changes including pollution and climate change. Genetic erosion in small populations, owing to fragmentation of natural habitats, is expected to obstruct such adaptive responses: (i) genetic drift will cause a decrease in the level of ada...

While extensive population genetic theory predicts conditions favoring evolution of self-fertilization versus outcrossing, there is no analogous theory that predicts conditions favoring evolution of inbreeding avoidance or inbreeding preference enacted through mate choice given obligate biparental reproduction. Multiple interacting processes complicate the dynamics of alleles underlying such in...

Inbreeding depression is widely hypothesized to drive adaptive evolution of precopulatory and post-copulatory mechanisms of inbreeding avoidance, which in turn are hypothesized to affect evolution of polyandry (i.e. female multiple mating). However, surprisingly little theory or modelling critically examines selection for precopulatory or post-copulatory inbreeding avoidance, or both strategies...

Inbreeding depression has been documented in many insect species, but the degree to which it varies among traits within populations and among populations within species is poorly understood. We used a single-generation factorial breeding design to examine variation in inbreeding depression among three populations of the seed-feeding beetle, Stator limbatus Horn (Coleoptera: Chrysomelidae: Bruch...

As populations decline to levels where reproduction among close genetic relatives becomes more probable, subsequent increases in homozygous recessive deleterious expression and/or loss of heterozygote advantage can lead to inbreeding depression. Here, we measure how inbreeding across replicate lines of the flour beetle Tribolium castaneum impacts on male reproductive fitness in the absence or p...

Little is known about how inbreeding alters selection on ecologically relevant traits. Inbreeding could affect selection by changing the distribution of traits and/or fitness, or by changing the causal effect of traits on fitness. Here, I test whether selection on egg size varies with the degree of inbreeding in the seed-feeding beetle, Stator limbatus. There was strong directional selection fa...

Levels of inbreeding are highly variable in natural populations. Inbreeding can be due to random factors (like population size), limited dispersal, or active mate choice for relatives. Because of inbreeding depression, mating with kin is often avoided, although sometimes intermediately related individuals are preferred (optimal outbreeding). However, theory predicts that the advantages of matin...