Life History Characteristics ofDiorhabda CarinulataUnder Various Temperatures

Abstract

Tamarisk leaf beetles, Diorhabda spp., have been released in the western United States as a biological control agent for the invasive weed Tamarix spp. There have been a few studies on the life cycle, host preferences, and field observations of Diorhabda; however, their ecophysiological characteristics under various temperature regimes are not clearly understood. In this study, life history characteristics such as growth, fecundity, and mortality of Diorhabda Carinulata (Desbrochers), the species established in the Colorado River basin, were investigated under various temperatures. Beetles were housed at various temperatures (room, constant high, and variable high) and their life cycle from eggs to reproductive adult was observed. Body size at various larval and adult stages, as well as their developmental time decreased with increasing temperature. Between the two temperature treatments, beetles at diurnally fluctuating temperature (variable high treatment) grew slower and produced fewer eggs per clutch when compared with the constant high treatment. Despite smaller in size, beetles grew fastest at the constant high temperature and produced most eggs per clutch compared with the other two treatments. Overall, severely high temperatures seem to have a debilitating effect on Diorhabda at early larval stages with nearly 50% mortality. The study has potential implications for the tamarisk beetle biocontrol program in the southwestern United States.

Effect of short-term high-temperature exposure on the life history parameters of Ophraella communa

“…communa to short intervals of high temperature exposure in the range of 42 to 44 °C was indicated by an immediate decline in survival. Rapid death under short-term heat exposure has also been reported in other beetles, including the Japanese beetle Popillia japonica 36 , the tamarisk leaf beetle Diorhabda carinulata 37 , and the ladybird beetle C . montrouzieri 25 .…”

“…avenae 35 , D . carinulata 37 , the bollworm Helicoverpa armigera 33 , the leafminer Liriomyza huidobrensis 51 , the flesh fly Sarcophaga crassipalpis 52 , the fruit fly Drosophila buzzatii 50 and the whitefly T . vaporariorum 23 .…”

Integrating conventional management methods with biological control for enhanced Tamarix management

“…Although there were stands of Tamarix inaccessible to mowing, the integration of mowing led to an overall reduction in food source and a greater likelihood beetles would emigrate in search of a food source, as noted on the San Juan and Dolores River (Jamison et al 2016). Elevated temperatures in laboratory conditions (up to 40 C) increased egg, larval, and pupal mortality in D. elongata (Herrera et al 2005) and larval mortality in D. carinulata (Acharya et al 2013). High summer temperatures were correlated with low humidity rates, and Lewis et al (2003) noted high D. elongata pupal mortality in outdoor mesh bags, attributing it to low humidity levels.…”