Food Consumption and Utilization by the Mexican Beetle, Zygogramlna bicolorata Pallister (Coleoptera:Chrysomelidae) on Parthenium hysterophorus Linnaeus

Quantitative food utilization indices were measured in different larval instars and physiological ages of adult Zygogramma bicolorata Pallister. Among the larval and adult stages of the beetle, third instar larvae and egg laying females ingested maximum food. Various growth parameters like relative consumption rate (RCR), relative growth rate (RGR) and approximate digestibility (AD) were relatively higher in the first, third and fourth instar and egg laying females. Efficiency of conversion of ingested food (ECI) and efficiency of conversion of digested food (ECD) were maximum in first, third and fourth instar larvae and decreasing trend was observed in second instar larvae. During preoviposition stage adult, these parameters increased tremendously in contrast to senescent stage.