Temperature dependent development of Lygus hesperus (Hemiptera: Miridae) nymphs

Authors: Cooper, William - Rodney; Spurgeon, Dale

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/17/2012
Publication Date: 6/13/2012
Citation: Cooper, W.R., Spurgeon, D.W. 2012. Temperature dependent development of Lygus hesperus (Hemiptera: Miridae) nymphs. Journal of Economic Entomology. 105: 860-865.

Interpretive Summary: The western tarnished plant bug is a major crop pest in the western United States. Improved knowledge of the effects of temperature on plant bug development is needed to better understand seasonal changes in plant bug population levels. We assessed the development of plant bugs from egg hatch to adulthood at nine constant temperatures from 50 to 100 degrees F. Plant bugs developed faster as temperature increased from 50 to 90 degrees F, but development slowed with further increases in temperature. Although plant bugs grew and developed at 50 and 100 degrees, at these temperature bugs died during or shortly after molting and none survived the entire period from hatch to adult. Development rates of males and females did not differ. Our non-linear models of temperature-dependent development will facilitate improved prediction of plant bug development compared with existing linear models. Our results will also improve design and interpretation of ecological studies by providing insights into the relationships between environmental conditions and plant bug development and survival.

Technical Abstract: Lygus hesperus Knight (Hemiptera: Miridae) is a key pest of fruit and vegetable crops, forages, and cotton (Gossypium spp.) in the western United States. Accurate models describing relationships between temperature and L. hesperus development are critical to the study of seasonal L. hesperus population dynamics. Development of L. hesperus nymphs was assessed at nine constant temperatures from 10 to 37.8 degrees C. The relationships between temperature and development for each L. hesperus instar, and for the entire nymphal stage, were best described by six-parameter biophysical models indicating both low- and high-temperature inhibition of development. Development rates asymptotically approached zero with decreasing temperature in the lower thermal range, and decreased with increasing temperatures above 32.2 degrees C. Nymphs did not survive from egg hatch to adulthood at either 10 or 37.8 degrees C, and nymph mortality was >90% at both 12.8 and 35.0 degrees C. The fifth instar exhibited the longest stadium, whereas the shortest stadia were associated with the second and third instars. Development rates of males and females did not differ, and the ratio of males to females was not different from 1:1 at any temperature. Our temperature-dependent development rate models for L. hesperus nymphs will facilitate control of insect physiological age in controlled laboratory experiments, and should be useful in planning and interpreting field studies on L. hesperus population dynamics.