Inverse link between density and dispersal distance in butterflies: field evidence from six co‐occurring species

Abstract

A pertinent question in animal population ecology is the relationship between population abundance, density, and mobility. Two extreme ways to reach sufficient abundance for long-term persistence are to inhabit restricted locations at high densities, or large areas in low densities. The former case predicts low individual mobility, whereas the later predicts high one. This assumption is rarely tested using across-species comparisons, due to scarcity of data on both mobility and population sizes for multiple species. We used data on dispersal and local population densities of six butterfly species gained by mark-recapture, and data on their (relative) regional abundance obtained by walking transects in a landscape surrounding the mark-recapture sites. We correlated both local density and regional abundance against slopes of the inverse power function, appropriate for describing the shape of dispersal kernel. Local densities correlated negatively with the dispersal kernel slopes both when sexes were treated as independent data points and if treated together. For regional abundance, the correlation was also negative but only marginally significant. Our results corroborate the notion that a trade-off exists between living in dense populations and having poor dispersal, and vice versa. We link this observation to resource use by individual species, and distribution of such resources as host plants in the study landscape.

Does movement behaviour predict population densities? A test with 25 butterfly species

“…Our result contrasts with previous studies; for example, Konvicka et al . () found a negative relationship between lifetime movement, another ‘simple’ movement metric and local patch densities for six butterfly species. However, a key difference is that we define move lengths over very small steps (on the scale of minutes), whereas Konvicka et al .…”

“…; Konvicka et al . ; Unglaub et al . ), high population densities are assumed to reflect higher quality patches, and the causal relationships are similar to the diffusion‐density relationship we observe: higher resource density leads to slower movement, which leads to higher densities of foraging organisms.…”

Has the currently warming climate affected populations of the mountain ringlet butterfly, Erebia epiphron (Lepidoptera: Nymphalidae), in low-elevation mountains?

“…For the vast majority of temperate zone butterfl ies with a single generation per year (e.g., Konvicka et al, 2012) and those with multiple but temporally non overlapping generations (e.g., Soulsby & Thomas, 2012), annual adult recruitments curves are domed with a rather steep initial increase, distinct peaks and a subsequent gradual decline. This is a result of a rapid emergence of males and more gradual emergence of females (the "protandry" phenomenon, refl ecting male competition for females, cf.…”

Life history influences how fire affects genetic diversity in two lizard species

“…Other factors that may influence gene flow, such as population density (Konvicka et al . ), topography (Cushman et al . ) and geographical distance (Wright ), can be incorporated into landscape genetics analyses, with fire mosaics, to understand the factors influencing genetic structure (Cushman & Landguth ).…”