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Submitted to: Entomologia Experimentalis et Applicata
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 8/11/2011 Publication Date: 10/17/2011 Citation: Williams III, L.H., Hagler, J.R., Tonkel, K.C. 2011. Retention of immunolabels by Diorhabda carinulata (Coleoptera: Chrysomelidae), a biological control agent of saltcedar. Entomologia Experimentalis et Applicata. 141:154-162. Interpretive Summary: Beneficial insects are the primary means of controlling most weeds in natural areas and rangelands in the western U. S. These insects are extremely vulnerable to other insects that eat them–if too many of the beneficial insects are devoured then their populations will not multiply and they will not be able to successfully attack the weed. Therefore, it is extremely important to identify insect predators that attack beneficial insects, and understand the role they play in their population growth. We used immunoprotein labels to study the feasibility of marking the saltcedar leaf beetle by submersion in rabbit or chicken protein solution. Duration of label retention was measured in laboratory and field with beetles, and in the laboratory with beetle eggs. For adults, both labels showed >80% retention for 14 days. Retention was not affected by high temperatures. Eggs externally labeled with proteins exhibited 100% retention. Interestingly, larvae emerging from externally labeled eggs were labeled both externally and internally, and internal labels of newly hatched larvae were generally stronger than external labels. To our knowledge, this is the first case of protein being transferred from the egg to immature stages of an insect, as well as the first case of an externally applied label being detected internally. Our study demonstrated that protein marking technology has utility for studies of predator-prey associations in the saltcedar leaf beetle. Technical Abstract: This study examines the feasibility of marking Diorhabda elongata (Brullé) by submersion in rabbit or chicken immunoglobulin G (IgG) solution. Duration of immunolabel retention was measured via enzyme-linked immunosorbent assays in laboratory and field trials with adults, and in the laboratory with eggs. For adults, both labels showed >80% retention for ca. 14 days under all conditions. Retention was not affected by high temperatures. Rabbit IgG sometimes exhibited greater retention than chicken IgG, although both proteins provided acceptable labels. Eggs externally labeled with proteins exhibited 100% retention for both proteins for the duration of the egg stage. Interestingly, larvae emerging from externally labeled eggs were labeled both externally and internally. Moreover, internal labels of 1st instars were generally stronger than external labels for rabbit IgG. To our knowledge, this is the first case of an IgG being transferred from the egg to immature stages of an insect, as well as the first case of an externally applied label being detected internally. Age of eggs at the time of label application affected intensity of external label on neonate 1st instars; larvae emerging from eggs that were >2 days old when labeled exhibited stronger label retention than larvae emerging from eggs <2 days old when labeled. Our study demonstrated that protein marking technology has utility for studies of dispersal and predator-prey associations in D. elongata. |
