Recommendations on the use of alcohols for preservation of ant specimens (Hymenoptera, Formicidae)

Collectors use a variety of concentrations and types of alcohols to preserve ant specimens. We evaluated existing literature, experimental evidence, and expert myrmecological advice to determine what kind and concentration of alcohol will result in the best preserved specimens for card-point mounting and DNA extraction. For our experimental evaluation, we killed and stored Solenopsis invicta, Camponotus floridanus, and Dorymyrmex bureni workers in isopropanol and ethanol at four concentrations (70, 85, 95, 100%) over three time periods (24 h, 1 month, 6 months). We then compared specimen condition and amenability to manipulation for mounting on card points. Specimens stored in either 95% isopropanol or 95% ethanol for time periods longer than 24 h produced the best specimens for mounting. A literature review revealed that DNA is best preserved in 95-100% ethanol due to the ability of ethanol to more rapidly penetrate cellular membranes and deactivate DNase activity than other primary alcohols. We recommend that general collections of adult ant specimens should be killed and stored in 95% ethanol. Following this recommendation will result in ant specimens that are easier to mount for museum collections and better preserved for molecular studies. A variety of other killing and preservation techniques relevant to the study of ants are also discussed.