Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2012
Publication Date: 12/5/2012
Citation: Snodgrass, G.L., Jackson, R.E., Perera, O.P., Allen, K.C., Luttrell, R.G. 2012. Effect of food and temperature on emergence from diapause in the tarnished plant bug (Hemiptera: Miridae). Environmental Entomology. 41:1302-1310.
Interpretive Summary: The tarnished plant bug is the number one pest of cotton grown in the mid-South. It is controlled in cotton almost exclusively with insecticides, and in the mid-South populations are present each year that are highly resistant to many of the insecticides which previously were used for its control. Non-insecticidal control methods are badly needed to reduce and help prevent an increase in the insecticide resistance problem. Most of the possible non-insecticidal control methods require a better understanding of the basic biology of the tarnished plant bug in the mid-South. The research reported in our manuscript provides new knowledge on how tarnished plant bugs overwinter as adults in the mid-South. Diapausing adults were found to be able to break diapause during December when a food stimulus was present. This stimulus was the winter host plant Lamium amplexicaule L. (henbit). Temperature also affected emergence from diapause, and the winter weather had to be mild enough for henbit to bloom in order for overwintering adults on henbit to break diapause. The part of the overwintering population found in plant debris broke diapause in the absence of food or temperature stimuli during January by use of an internal clock.
Technical Abstract: The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), overwinters as a diapausing adult in North America. Overwintering adults were collected near Stoneville, MS from blooming henbit, Lamium amplexicaule L., and from plant debris during December and January and dissected to determine their reproductive status. Averaged over four winters, male and female tarnished plant bugs collected from henbit broke diapause at a significantly higher rate than males and females from plant debris during each week of December and the first week of January. Both sexes in each habitat were nearly all reproductive by the end of January. Adults overwintering in plant debris broke diapause during January in the absence of a food stimulus in all five years studied. This emergence was thought to be controlled by an internal clock. Laboratory and field studies showed that emergence from diapause could be influenced by food, sex, and temperature. Adults overwintering on a suitable food source, blooming henbit, broke diapause during December in the four years studied, and males broke diapause more rapidly than females. Food quality was important in emergence from diapause, and females on blooming henbit broke diapause at a significantly higher rate than females on non-blooming mustard, Brassica juncea (L.) Cosson. Laboratory tests showed that diapausing adults reared in the laboratory and held at a diapause-maintaining photoperiod of 10:14 (L:D) h could be broken from diapause using food and temperature stimuli. The lower thermal threshold for development to reproductive adults was found to be near 10oC. The ability of diapausing adults to respond to food and temperature stimuli in December can enable the tarnished plant bug to take advantage of warm winters and winter hosts to produce a new generation earlier.