DOI: 10.5061/dryad.fxpnvx134
title: Determining oviposition preferences to inform population reinforcement of the specialist chequered blue butterfly (Scolitantides orion)

description: Many Lepidoptera species are declining to the point that active measures
 such as reinforcements and reintroductions are necessary to maintain
 viable populations. To maximise success of such efforts, we need to
 understand the factors influencing habitat preferences for oviposition. In
 a Swedish island population of the red-listed chequered blue butterfly
 (Scolitantides orion), we characterized oviposition preference by
 documenting whether the presence and abundance of eggs increased with size
 and local density of its host plant, orpine (Hylotelephium telephium), and
 was associated with nectar plant abundance, degree of shading, and ground
 cover composition within small and large circular plots (1 m vs. 5 m
 radius) around focal plants. To reinforce a tiny population on a
 neighbouring island, we released 127 pupae and 46 imagos and recorded
 oviposition for two seasons. The probability of receiving eggs increased
 with focal host plant size, and also with mean size of other host plants
 and cover of lichens within the large plots. The abundance of eggs within
 large plots increased with host plant density and amount of lichen cover.
 Habitat characteristics of the large plots predicted oviposition better
 than did those of small plots, and both outperformed models including host
 plant size only. In the reinforcement population, all released pupae
 hatched, and we found a total of 507 eggs on 272 host plants during the
 release season. Eggs were present on 5% of examined host plants, and
 median distance to a release spot was 19.3 m. In the following year, we
 found 420 eggs on 209 plants, and median distance to a release spot
 increased to 35.7 m, indicating diffusion through the habitat. Practical
 implication. The chequered blue butterfly prefers to oviposit on large
 host plants in patches with high host density and high cover of lichens.
 To identify suitable release habitats, environmental conditions should be
 considered in an area of ca 80 m2. The reinforcement shows that small
 releases can be successful, and suggests that similar low-effort
 approaches can be effective to boost local populations of many threatened
 butterflies, provided suitable habitats are available.
description: # Determining oviposition preferences to inform population reinforcement
 of the specialist chequered blue butterfly (Scolitantides orion)
 [https://doi.org/10.5061/dryad.fxpnvx134](https://doi.org/10.5061/dryad.fxpnvx134) ## Description of the data and file structure In a Swedish island population of the red-listed chequered blue butterfly (*Scolitantides orion*), we characterized oviposition preference by documenting whether the presence and abundance of eggs (i) increased with size and local density of its host plant, orpine (*Hylotelephium telephium*), and (ii) was associated with nectar plant abundance, degree of shading, and ground cover composition within small and large circular plots (1 m vs. 5 m radius) around focal plants. ### Files and variables #### File: EcolSolEvi\_data.xlsx **Description:**  ##### Variables | Focal plant scale |   | | :----------------- | :----------------------------------------- | | Variable | Explanation | | plot | 60 study plots (plot ID - number) | | eggs\_0\_1\_focal | Presence of eggs on focal plant (binomial) | | eggs\_total\_focal | Number of eggs on focal plant (number) | | nr\_leaves\_focal | Number of leaves on focal plant (number) | | Small plot scale |   | | :------------------------------- | :-------------------------------------------------------------------- | | Variable | Explanation | | plot | 60 study plots (plot ID - number) | | eggs\_0\_1\_focal | Presence of eggs on focal plant (binomial) | | eggs\_0\_1\_plot | Presence of eggs in plot (binomial) | | arc\_prop\_eggs | Proportion of plants with eggs in plot (proportion) | | eggs\_total | Number of eggs in plot (number) | | nr\_leaves\_focal | Number of leaves on focal plant (number) | | nr\_hosts\_without\_focal | Number of host plants in plot (excluding focal plant) (number) | | nr\_hosts\_with\_focal | Number of host plants in plot (number) | | nr\_leaves\_plot\_without\_focal | Mean number of leaves on host plants (excluding focal plant) (number) | | nr\_leaves\_plot\_with\_focal | Mean number of leaves on host plants (number) | | flowers\_plot | Number of nectar flowers in plot (number) | | canopy\_cover | Canopy cover in plot (%) | | Large plot scale |   | | :------------------------------- | :-------------------------------------------------------------------- | | Variable | Explanation | | plot | 60 study plots (plot ID - number) | | eggs\_0\_1\_focal | Presence of eggs on focal plant (binomial) | | eggs\_0\_1\_plot | Presence of eggs in plot (binomial) | | arc\_prop\_eggs | Proportion of plants with eggs in plot (proportion) | | eggs\_total | Number of eggs in plot (number) | | nr\_leaves\_focal | Number of leaves on focal plant (number) | | nr\_hosts\_without\_focal | Number of host plants in plot (excluding focal plant) (number) | | nr\_hosts\_with\_focal | Number of host plants in plot (number) | | nr\_leaves\_plot\_without\_focal | Mean number of leaves on host plants (excluding focal plant) (number) | | nr\_leaves\_plot\_with\_focal | Mean number of leaves on host plants (number) | | flowers\_plot | Number of nectar flowers in plot (number) | | canopy\_cover | Canopy cover in plot (%) | | pc1 | PC1 axis score (pc score) | | pc2 | PC2 axis score (pc score) | ## Code/software The data are in excel format. No codes are included.