Study

Planting California pipevine Aristolochia californica in gardens does not benefit the pipevine swallowtail Battus philenor for 40 years; trials in San Francisco, California, USA

  • Published source details Levy J.M. & Connor E.F. (2004) Are gardens effective in butterfly conservation? A case study with the pipevine swallowtail, Battus philenor. Journal of Insect Conservation, 8, 323-330

Summary

‘Butterfly gardening’ involves planting caterpillar food plants and nectar plants in gardens. Some environmental organisations have suggested that gardens could replace lost natural habitat for butterflies. In California, the pipevine swallowtail Battus philenor lays eggs exclusively on the California pipevine Aristolochia californica. This study compared the butterfly’s use of the plant in gardens where it was planted to encourage butterflies, with that in natural populations, in and around San Francisco, California, USA.

California pipevine plants were monitored in nine gardens and at nine natural sites in 2001, and 23 gardens and 11 natural sites in 2002. The plants were observed for 15 minutes to record visiting adult butterflies, and the foliage was inspected for eggs or caterpillars, every week from March to mid-July each year. The height and area covered by each vine was recorded, and the year of planting. Natural vines, for which there was no record of age, were classed as being 80 years old, equivalent to the oldest garden planting.

Adult pipevine swallowtails visited and laid eggs in significantly fewer garden sites than natural sites (visits to eight of nine natural sites and one of nine gardens in 2001; all natural sites and only eight of 23 gardens, in 2002). All visited natural sites had egg-laying, but only 75% of visited gardens had egg-laying.

Egg survival rates were 18-24% higher in natural sites than gardens.
 
The presence of pipevine swallowtails was related to the age of planting and size of the plant. No garden pipevines less than five years old attracted butterflies, and no garden pipevines less than ten years old supported larvae to maturity. The data suggested that California pipevine plants need to be at least 40 years old and have 185 m2 of foliage before they can support pipevine swallowtail larvae through complete development.
 
The practice of introducing wild-caught pipevine swallowtail larvae to recently planted pipevines in gardens is likely to adversely affect the population rather than helping it. The authors argue that butterfly gardening should not be promoted as a conservation tool for the pipevine swallowtail.
 
 
Note: If using or referring to this published study, please read and quote the original paper, the abstract of which can be viewed at: http://www.springerlink.com/content/k203737076x895r7
 

Output references

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, terrestrial mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 18

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.


Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust