Author
 |
Ugine, Todd |
|
Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/3/2011 Publication Date: 2/1/2012 Citation: Ugine, T.A. 2012. Developmental time and age-specific life tables for Lygus lineolaris (Heteroptera: Miridae). Environmental Entomology. 41(1):1-10. http://dx.doi.org/10.1603/EN10210. Interpretive Summary: Insect developmental rates are known to be influenced by temperature. Knowledge of developmental rates is important when considering tactics to manage insect pests. Tarnished plant bugs, Lygus lineolaris, are a particularly damaging insect pest of cotton and many seed and forage crops. They also are able to readily develop resistance to synthetic chemical pesticides. Studies were conducted to determine exactly how temperature affects the growth rate of tarnished plant bugs. This information will inform researchers about how lygus populations are likely to grow during field seasons and may also help to make better guesses about what alternatives to chemical pesticides are worth pursuing. It was determined that increasing temperature led to faster development times for all of the different life stages of tarnished plant bug. Temperature also had a large influence on the number of eggs laid each day by female tarnished bugs and on the number of total eggs laid. The results of this research will help to predict insect age for use in tests of alternatives to chemical pesticides, will make mass rearing operations more efficient in that the optimum temperature for development and egg laying are know known, and will help to predict the growth patterns of lygus field populations when used with field temperature data. Technical Abstract: Developmental times and survivorship of tarnished plant bug (TPB) nymphs, Lygus lineolaris (Palisot de Beauvois), and longevity and reproduction of adult tarnished plant bug adults reared on green beans were studied at multiple constant temperatures. The developmental time for each life stage and the total time from egg to adult decreased with increasing temperature. Eggs required the longest time to develop followed by fifth instars and then first-instars. Total developmental time from egg to adult was shortest at 32ºC, requiring 18.0 ± 0.3 d and 416.7 ± 31.3 degree days above 7.9ºC, the estimated minimum temperature for development from egg to adult. Sex did not affect total developmental times and did not affect median survival time. Adults lived significantly fewer days at high temperatures (30-32ºC: 17-19 d) compared to temperatures below 30ºC (range: 24.5–39.4 d) and the number of eggs laid per day increased from ca. 4 at 18ºC to a maximum of 9.5 eggs per day at 30ºC. Total egg production over the lifetime of female TPB increased with temperature reaching a maximum of 175 eggs on average at 27ºC, total egg production declined at temperatures above 27ºC (30ºC: 110.8, 32ºC: 77.3 eggs per female). The highest net reproductive rate 74.5 (R0) was obtained from insects maintained at 27ºC. The intrinsic rate of natural increase (rm) increased linearly with temperature to a maximum value of 0.1852 at 30ºC, and then decreased at 32ºC. Generation and doubling times of the population were shortest at 30ºC, 21.0 and 3.7 d, respectively. |
