Investigation of secondary metabolites in bean cultivars and their impact on the nutritional performance ofSpodoptera littoralis(Lep.: Noctuidae)

Abstract

Spodoptera littoralis (Boisd) is globally recognized as a destructive polyphagous insect pest of various crops in the world. It is commonly managed by chemical pesticides, which can cause deleterious effects such as environmental pollution, toxicity to non-target organisms and the emergence of secondary pests. Hence, investigations into alternative pest control strategies such as the use of resistant host plant cultivar against S. littoralis is important. This study aimed to explore the nutritional performance of S. littoralis larvae in dependence on total anthocyanin, flavonoid, and phenol levels across 11 bean cultivars (Phaseolus and Vigna spp.) under laboratory conditions. The results revealed that the Mashhad cultivar accumulated the highest amount of total phenols (13.59 mg ml−1), whereas Yaghout and Arabi cultivars posed the lowest total phenols contents (1.80 and 1.90 mg ml−1, respectively). Across larval instars (third to sixth), the highest consumption index and relative consumption rate were recorded on the Mashhad cultivar. The lowest values of efficiency of conversion of ingested food and the efficiency of conversion of digested food of total larval instars were detected in the larvae which were reared on the Mashhad cultivar. Likewise, the lowest value of the index of plant quality (IPQ) was obtained in the Mashhad cultivar; however, IPQ was figured out at the highest level in the Arabi cultivar. Our findings show that the differential accumulation of secondary metabolites would change the nutritional quality of plants for S. littoralis. Based on the findings, the Mashhad cultivar may serve as a candidate for either integrated pest management or breeding programs aiming at controlling this pest.

Life Table Parameters and Digestive Enzyme Activity of Spodoptera littoralis (Boisd) (Lepidoptera: Noctuidae) on Selected Legume Cultivars

“…In addition, the intrinsic rate of increase ( r ) of S. littoralis was positively correlated with starch content, which is congruent with the relatively high r value characterizing S. littoralis that developed on Arabi. Furthermore, these results are consistent with the previous investigations that related macronutrient and biochemical traits of various plants to herbivore performance [ 4 , 18 , 39 , 40 ]. The r value is related to life history traits, such as developmental time, survival rate, and fecundity.…”

“…Despite the economic importance of S. littoralis on legumes, there have been no life table or performance investigations published for this pest on this important crop. Previous studies with various other plant species have revealed significant variation in host plant suitability to S. littoralis [ 4 , 26 , 27 , 28 ]. In general, the use of plant tolerance or resistance traits as a means of managing S. littoralis has been relatively neglected.…”

“…The shortest developmental time occurred on the common bean, Arabi, and may be related to the high starch content characterizing this cultivar. Furthermore, secondary plant metabolites could also be factors affecting performance and development of S. littoralis [ 4 ]. Adult reproductive potential depends fully on nutrition acquired during the immature stage and therefore duration of immature stages affects the fecundity and longevity of adults [ 16 ].…”

“…The Egyptian cotton leafworm, Spodoptera littoralis (Boisd) (Lepidoptera: Noctuidae), is a highly polyphagous and destructive pest which attacks a wide range of economically important crops throughout the world [ 1 , 2 , 3 , 4 ]. Lepidopteran larvae are of global phytosanitary concern due to their ability to attack a variety of plant structures, negatively affecting crop quality and causing economic losses [ 5 ].…”

“…Nutritional performance of S. littoralis on bean cultivars, including red kidney bean, common bean, white kidney bean and cowpea was demonstrated by Shishehbor and Hemmati (2022), who reported that the common bean, Arabi, and white kidney bean, Almas, were suitable hosts for S. littoralis . However, the cowpea, Mashhad, was identified as unsuitable [ 4 ].…”