nectar sources (Shreeve 1995). Nevertheless, understanding the effects that conspecific density

has on dispersal is key in this study of butterfly abundances at butterfly farms, which have

artificially high conspecific densities due to their butterfly stock and/or dense planting of nectar

sources inside and outside the cages.

Conspecific density

 Previous studies have observed that individuals disperse at a higher rate away from an area

when the area exhibits a low conspecific density, suggesting a negatively density-dependent

dispersal (Gilbert & Singer 1973; Kuussaari et al. 1996, 1998), while other observations find that

individuals disperse at higher rates away from areas exhibiting high conspecific density,

suggesting a positively density-dependent dispersal (Dethier & MacArthur 1964; Odendaal et al.

1989; Baguette et al. 1996, 1998). The next two sections will concentrate on the differences

between these two concepts and common arguments in favor of one or the other.

Negatively density-dependent dispersal

 Negatively density-dependent dispersal is a term used to describe a situation in which

individuals disperse at a higher rate away from an area when the area exhibits a low conspecific

density (Gilbert & Singer 1973; Kuussaari et al. 1996, 1998). According to Hanski et al. (1994)

and Kuussaari et al. (1998), this could be the result of mate scarcity, as a butterfly inhabiting an

area with low conspecific density would have a lesser chance of finding an appropriate mate and

may choose to leave the patch in order to hopefully increase chance of finding a mate elsewhere.

The concept of high disperal rates away from areas of low conspecific density gave rise to the

conspecific attraction hypothesis, which states that high density populations will result in higher

immigration rates to and lower emigration rates away from the habitat in question (Ray et al.,

1991). There are two supporting arguments to this hypothesis. The first, given by Odendaal et

al. (1989), is that butterflies are attracted to and ultimately remain in habitats with high