LARVAE OF THE ELATERID BEETLES GLEN 



METHODS AND PROCEDURE 



The primary purpose of the rearing project at the Saskatoon lab- 

 oratory has been to associate larval and adult stages. Considerable 

 information on the biology of certain species has been obtained, but 

 this has been largely incidental to the main purpose. Through the 

 cooperation of colleagues and friends more than 4,000 elaterids have 

 been collected for rearing. Some 250 larvae have been reared to 

 adults and 30 otliers to pupae. The reared adults represent more than 

 50 species, of which 20 belong to the tribe Lepturoidini and 7 to the 

 genus Ludiiis. 



In the Holarctic region most species of Elateridae pupate in July 

 or early August, and best results have been obtained from collections 

 made just prior to or during that period. Usually a high percentage 

 of the large larvae collected at this time pupate within a few weeks, 

 and in addition pupae and young adults may be found in their pupal 

 chambers along with their larval exuviae. 



The largest larvae of each type were selected for rearing. Only 

 one specimen was put in each container, which usually was a i -ounce, 

 2-ounce, or 3-ounce salve tin. In this way confusion was avoided 

 in associating adults with larval exuviae and losses from disease and 

 predatism were minimized. The containers were nearly filled with 

 appropriate material such as soil, wood, or leaf litter, taken from the 

 exact spot where the larvae were found. Potato, crushed wheat, and 

 fresh grass roots were commonly used for food and predaceous 

 species occasionally were given decapitated coleopterous and lepidop- 

 terous larvae. Small amounts of M^ater were added weekly to each 

 container to keep the contents just slightly moist. Most of the rearing 

 was done at room temperature, but some specimens were reared in 

 controlled-temperature cabinets operating at 60° F. to 80° F. Very 

 little benefit was noted from maintaining the larvae at any constant 

 temperature, and varying temperatures were not thoroughly tested. 



Where exact data on pupation were desired, the pupa or prepupal 

 larva was gently transferred from its pupal chamber to a depression 

 made on the surface of the soil (or litter), where it could be observed 

 daily with a minimum of disturbance. Glass-topped tins or glass 

 vials, partially filled with moist soil or litter, were used occasionally 

 as containers for specimens under daily observation. In every instance 

 the last larval exuvium and the pupal exuvium were preserved. 



