No abstract

Laboratory insect colonies are an essential part of experimental insect science. Formalized naming of laboratory stocks is standard practice in model organisms such as mice and fruit flies, but crucial details such as colony origin and standard names are often lacking in nonmodel systems. For institutions involved in rearing multiple nonmodel species, effective monitoring requires standardized naming and nomenclature, from establishment to production, distribution, and publication. Insect rearing has been the cornerstone of the Insect Production and Quarantine Laboratories (IPQL) at the Great Lakes Forestry Centre for over 70 yr, but the histories of the insect colonies in this facility have not been adequately documented and formal, standardized names do not exist. We propose a standardized naming framework that we applied to the eight species reared at the IPQL to rectify these deficiencies. We also present the origin and history of each colony, essential information that is challenging to obtain post hoc. We suggest that other research institutions consider developing similar standards, so they can accurately document, communicate, and track laboratory insect their within the facilities and through the scientific literature.

Exposing larvae of the spruce budworm, Choristoneura fumiferana (Clemens), to sublethal (≤ 50% lethal dose) levels of Bacillus thuringiensis subsp. kurstaki at various stages of their development significantly increased development time to the pupal stage and reduced pupal size and number of eggs laid per female, but did not affect the proportion of embryonated eggs. The changes in larval development time, pupal weight and fecundity depended on the larval stage that was treated. Exposure of fourth instars delayed larval development and reduced only male pupal weights with no effects on fecundity. Exposure of sixth instars delayed larval development to a lesser extent than exposure of fourth instars but had a pronounced effect on weight of both male and female pupae. The effect on pupal weight was sex dependent, as males tended to be more affected than females. The reduction in male pupal weight did not appear to influence fecundity, because the effect of exposure was explained by the change in female pupal weight. Effects on larval growth and pupal weight were proportional to the dose that was ingested during exposure, and were observed at doses as low as one‐tenth of the LD50. Ingestion of an LD50 caused a 29 or 45% delay in development of, respectively, female or male larvae when exposed as fourth instars and a 30% reduction in female pupal weight when larvae were exposed as sixth instars.

A larval population of spruce budworm, Choristoneura fumiferana (Clemens), was monitored for 5 d following aerial application of a commercial formulation of Bacillus thuringiensis Berliner subsp. kurstaki to investigate dose acquisition and expression (larval mortality, recovery, feeding, and growth) in relation to spray deposition and persistence of spray deposits. The main objective was to test if previous laboratory observations on how B. thuringiensis affects feeding and dose ingestion by spruce budworm larvae hold true under field conditions. About 40% of the treated population ingested a lethal dose within 1 d after spray application. Lethally dosed larvae died without further feeding upon transfer from treated foliage to (untreated) artificial diet. Resumption of feeding by larvae that survived the treatment was delayed relative to larvae from the control population during 3 d following spray application; during that time, normal feeding activity and larval weight gain were suppressed. Inhibited feeding by survivors appeared to prevent further dose uptake because the proportion of lethally dosed larvae in daily collections did not increase despite significant residual spray deposits in budworm feeding sites. Restoration of "normal" recovery times by the fourth day coincided with a 65–85% reduction in persistence of the pathogen on the foliage and did not result in further lethal dose acquisition, as treatment-induced mortality dropped to about 20% on the 4th and 5th days. The observations are consistent with previous laboratory observations of how B. thuringiensis affects larval feeding and with the hypothesis that feeding inhibition may be a limiting factor in the acquisition of a lethal dose.