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Individual study: Captive rearing large blue butterflies Maculinea spp. in housed ant colonies works for some species but not others; laboratory experiments at the Institute of Terrestrial Ecology, Dorset, UK

Published source details

Wardlaw J.C., Elmes G.W. & Thomas J.A. (1998) Techniques for studying Maculinea butterflies: I. Rearing Maculinea caterpillars with Myrmica ants in the laboratory. Journal of Insect Conservation, 2, 79-84

Summary

Species of large blue butterfly Maculinea spp., whose larvae live as parasites in ant nests (Myrmica spp.), are protected in most countries. Two species, the alcon blue M. alcon and the mountain alcon blue M. rebeli are brood parasites (‘cuckoos’) tended by worker ants. Three species - the large blue M. arion, the scarce large blue M. teleius and the dusky large blue M. nausithous behave more like predators in ant nests. This study tested methods for captive rearing large blues in a laboratory at the Institute of Terrestrial Ecology, Dorset, UK.

Maculinea eggs were collected on flowering stems of food plants (gentian Gentiana spp., wild thyme Thymus spp, oregano Origanum spp., or great burnet Sanguisorba officinalis). Flowers were kept cool in narrow-necked vases in the laboratory, sprayed daily with water. Eggs in groups were separated before hatching by cutting individual florets carrying eggs and pinning them to other flower heads in potted plants.

Host ant Myrmica spp. colonies were collected from sites without large blues, by excavating nests. Queens, brood and workers were extracted using a pooter and transferred to two-chambered, plastic or plastic and glass nest boxes with separate dark (or red perspex) living chambers and light feeding chambers. Nine different nest designs were tested (numbers of attempts not given). Ants were fed with sucrose crystals or 5% sucrose solution and live fruit fly Drosophila larvae and pupae, kept humid and regularly cleaned (after an anaesthetic dose of CO2).

 

Fourth instar Maculinea caterpillars were introduced to ant colonies using soft-tipped forceps, after they dropped from the flower heads. There is no detail about where caterpillars were placed.

 

Colonies were kept between 7 and 25 °C.

The alcon blue and the mountain alcon blue have been successfully reared for various studies in ant colonies housed like this (success rates not given).

All attempts to rear large, dusky or scarce large blues with this method failed. The authors recommend boosting numbers of these species by rearing individual young caterpillars on potted plants in the laboratory, then introducing them to Myrmica nests at field sites with large populations of host ants.
 
 
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/1366-638X