Submitted to: Chinese Journal of Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/20/2006
Publication Date: 4/16/2007
Citation: Zhang, L., Li, B. 2006. Mating and oviposition behaviors of Diorhabda elongata deserticola Chen (Chrysomelidae, Coleoptera), an effective biocontrol agent of the saltcedar. Chinese Journal of Biological Control. 22(2):109-113. Interpretive Summary: Exotic saltcedars (in the plant genus Tamarix) from Asia, introduced into the U.S. in the 1820s, have invaded riverbottoms and lakeshores of the western U.S. where they cause great damage to native plant and animal communities. The leaf beetle, Diorhabda elongata, is one of the important insects that feed on saltcedars in China and help to control its abundance there. As part of a program on biological control of saltcedar in the U.S., the authors in China studied its mating behavior and measured its rate of egg laying in the laboratory and in the field and the rate of egg parasitization in the field. This will help researchers in the U.S. to produce laboratory colonies and help to estimate the degree of control of D. elongata after release in the field in the U.S.
Technical Abstract: Diorhabda elongata deserticola Chen is an important biocontrol agent for management of the invasive alien saltcedar in the United States. The mating and oviposition behaviors, including, the relationships between mating frequency and fecundity, and between oviposition style and parasitized eggs, of the leaf beetle were evaluated. Multiple mating and oviposition occurred during the life-time of the female. A mating behavior always consisted of three successive stages, pre-copulation, copulation and post-copulation, and the different behavior performances at each stage were described. Females started to lay eggs in 28 h after mating. Eggs were laid in masses each containing an average of seven eggs in the laboratory but more than half of the eggs (57.7%) was singly laid in the field. The oviposition time last 11.4 +/- 5.2 d and 141.0 +/- 88.1 eggs were laid per female during this period. More than half of eggs were laid in 14 d and over 80% eggs were laid in 28 d after adult eclosion. The numbers of parasitized eggs were negatively correlated with the sizes of egg masses. Mating activity peaked in the early morning and early afternoon and oviposition activity peaked at noon and in the evening. The percentage of parasitized eggs (Mymaridae) during the 2nd generation was 23.6%, higher than that during the 3rd generation (5.96%). Multiple mated females laid an average of 141.0 +/- 88.1 eggs and the oviposition period lasted 11.4 +/- 5.9 d, which were nearly 19 and 6 times more/longer than those of females mated once (7.5 +/- 2.8 eggs and 1.9 +/- 0.8 d, respectively).