|FREEMAN, THOMAS - NORTH DAKOTA STATE UNIV
Submitted to: Silverleaf Whitefly Research, Action and Technology Transfer Plan
Publication Type: Abstract Only
Publication Acceptance Date: 2/2/2001
Publication Date: N/A
Technical Abstract: Nymphs feed during all four stages of development. Once they begin to feed, they settle down and become flattened and appressed to the leaf surface. The rostrum of the nymph is short and has sensillia on the tip similar to those found on the labium of the adult. The rostrum also has a groove through which the stylet bundle passes similar to the labial groove of adults. The tip of the mandibular stylets are ridged or serrated and probably used in penetration of host leaf tissue. Stylets range from 114 um in first instars to as long as 200 um in fourth instars. The stylets can be at least partially withdrawn and reinserted during the feeding process. The nymphs increase in length and width with each molt and the newly formed stylets are also longer with each molt. However, the stylets do not increase in length proportional to the increase in size of the nymphs. What are the mechanisms involved in the insertion and withdrawal of the nymphal stylet? Do the stylets of subsequent molts use the salivary sheaths developed by an earlier instar? What is the function of the sensillia on the tip of the rostrum in sedentary nymphs? How does the nymph stylet find the phloem tissue in host leaves.